Monday, May 31, 2010

June 1st -- Start of Meteorological Summer

Although your calendar at home says summer begins on June 21st, meteorologists consider June 1st to be the start of summer! Part of this has to do with simplifying climatological data, since meteorologists and climatologists collect data on a month-by-month basis. Another reason is that the June 1st through August 31st time period is climatologically warmer in most areas of the northern hemisphere than the June 21st through September 22nd time period. Rockford, for example, has its climatologically warmest day around July 18th when our average high is 83 and our average low is 63. And the 18th of July is at the heart of the June 1st - August 31st time frame.

In addition, I found this information from a Wikipedia article that gives more insight into the start of meteorological summer:

"In 1780 the Societas Meteorologica Palatina, an early international organization for meteorology, defined seasons as groupings of three whole months. Ever since, professional meteorologists all over the world have used this definition.[5] So, in meteorology for the Northern hemisphere: spring begins on 1 March, summer on 1 June, autumn on 1 September, and winter on 1 December."

The June 21st date is called the astronomical first day of summer. This occurs when the suns rays are most direct in the northern hemisphere, or when they are directly above the Tropic of Cancer. From June 21st through the first astronomical day of Autumn (Sept. 23rd this year), the sun's most direct light gradually receeds from the Tropic of Cancer to the equator. This system has worked for astronomers for centuries. But now meteorologists and climatologists have come along, and they find that the June 1st date works better for them.   --TS

A Cool Front Shifts East Across the Area

A weak cool front is moving across northern Illiniois this morning.  Several areas of showers and thunderstorms have developed in the viscinity of the front.  A severe thunderstorm with large hail moved across Green and Rock counties early this morning.  A heavy thunderstorm formed just east of Rockford and moved across Boone into McHenry county between 8 am and 9 am this morning.  Another area of strong thunderstorms with severe weather moved into Bureau county around 10:30 am and diminished to below severe levels. That area will pass south of Rockford during the noon hour. So, it appears as if the showers and thunderstorms are over for northwestern Illinois, and are over for most of north central Illinois close to the Wisconsin border.  Drier air is moving in behind the front, and the clouds will break up during the afternoon.  High pressure will move into the Stateline from the northern plains tonight making for mostly clear skies, and cooler temperatures down into the upper 50's.  Tuesday will be mostly sunny and warmer with highs rebounding back up into the middle 80's.  A thunderstorm complex is expected to develop over northwestern Iowa on Tuesday afternoon.  That complex will move eastward, and may reach parts of norhtern Illinois during the ovenight hours on Tuesday night.  The threat of more storms will continue off and on Wednesday into Thursday as fronts continue to waver back and forth across the area.
By Meteorologist
Eric Nefstead

Few Storms this Morning

Watch for a few storms to develop this morning as the cold front continues to move through.  Any of the storms that do develop will have the possibility to produce heavy rain and hail.  Once the front passes through things should quiet down as the atmosphere becomes a little more stable later this afternoon.

Saturday, May 29, 2010

Storms Hold Off Until Sunday Night

It will be a clear and mild night, and Sunday will start off with sunshine, but there will partly cloudy skies by afternoon. It will be very warm with afternoon temperatures approaching 90 degrees. A cool front stretches southwest across the Dakotas and western Nebraska tonight.  It will be approaching the area Sunday evening.  There could be some scattered thunderstorms on Sunday night lasting through the morning hours on Memorial Day, and possibly through the afternoon, if the front slows down as it tries to move southeast across the area.  It appears as if Tuesday will be a dry day with lots of sunshine, but with fronts nearby there could be more showers and thunderstorms on Wednesday and Thursday. 
By Meteorologist
Eric Nefstead

Friday, May 28, 2010

Beach Weather This Weekend?

With forecast highs in the middle to upper-80s Saturday and Sunday, it might be tempting to take a dip in the lake. If you do so, just be forewarned that water temperatures are still very chilly on Lake Michigan! The southern Lake Michigan buoy is still only at 51 degrees! (Yes, it takes awhile for such a large body of water to warm-up.) Nearshore waters may be in the upper-50s or so, but that's still colder than most folks want to deal with. However, the smaller inland lakes are probably between 65 and 70 degrees right now. Still cool, but a little more tolerable! Have a great weekend, and happy Memorial Day!  --TS

Rain free weekend?

The first part of this holiday weekend looks just beautiful!  High pressure will remain in control today and Saturday keeping temperatures fairly comfortable with highs in the low to mid 80s.  By Sunday an area of low pressure will begin to move in from the northwest adding a few more clouds through the day.  The cold front will weaken some as it moves through during the day.  As it looks right now, the front will move through late Sunday night/early Monday morning.  If that were the case then most of Sunday will remain dry.  However, some indications are suggesting that the front may pass through a little earlier bringing rain into the forecast late Sunday afternoon.  I'm not too sold on the earlier solution, but it will be something to watch. 

Thursday, May 27, 2010

NOAA Expects Busy Atlantic Hurricane Season

According to NOAA, an active to extremely active hurricane season is expected for the Atlantic Basin this year, with 14 to 23 named storms, 8 to 14 hurricanes (winds of 74 mph or higher) and 3 to 7 of them possibly becoming major hurricanes (category 3 or higher). 

The outlook ranges exceed the seasonal average of 11 named storms, 6 hurricanes and 2 major hurricanes due to these factors:

Upper atmospheric winds will be conducive for storms.  Wind shear, which can tear storms apart, is expected to be weaker since El Nino is dissipating in the eastern Pacific.  Stronger wind shear during the 2009 hurricane season helped to suppress storm development.

Warm Atlantic Ocean Water.  Sea surface temperature are expected to remain above average where storms often form.  Record warm temperatures are now present in this region.

 High activity era continues.  Since 1995, the tropical multi-decadal signal has brought favorable ocean and atmospheric conditions in sync, leading to more active hurrican season.  Eight of the last 15 seasons rank in the top ten for the most named storms with 2005 in first place with 28 named storms.

According to Gerry Bell, Ph.D., lead seasonal hurricane forecaster at NOAA's Climate Prediction Center - "The main uncertainty in this outlook is how much above normal the season will be.  Whether or not we approach the high end of the predicted ranges depends partly on whether or not La Nina develops this summer.  We are currently in a neutral state, but conditions are becoming increasing favorable for La Nina to develop."

Wednesday, May 26, 2010

Lingering Evening Storms

A line of thunderstorms is developing from central Wisconsin back into northwest Illinois as of this writing. These storms are not severe, but they are moving slowly which means they could drop some heavy rain in a few spots. These storms don't have enough wind shear to last longer than an hour or so, but their outflow could trigger some new cells through this evening. Any new cells that develop are not expected to be severe, but could also produce some brief heavy downpours.

Earlier this afternoon, the town of Sycamore (in DeKalb county) had pea-size (or slightly larger) hail stones along with heavy rain. In Elburn, the power went out around 2:45pm as a tree fell on a powerline at Keslinger Rd. Other than that, I must admit this afternoon and evening were quieter than I expected!  --TS

Tuesday, May 25, 2010

Record Warmth Here, Record Cold out West!

As noted in a previous post, Rockford set a new record high on Monday of 93 degrees. While we are baking in an unseasonably warm and humid airmass, the western states are wishing they were so lucky! On Monday morning. 0.2" of snow fell on Salt Lake City, UT. This is the latest that measurable snow has ever fallen in that city! The previous record was May 18th when 1/2" of snow fell back in 1977. No snow in Sacramento, CA, but boy was it cold over the weekend! It was 45 degrees on Sunday morning, matching a record set back in 1960. On Saturday morning in nearby Redding, CA, the low was 34 degrees. This broke a record of 39 degrees set back in 1960!  --TS

Storm Reports

In addition to the 58mph gust at the Rockford Airport this afternoon, here are a couple more storm reports from the Stateline:

New Milford: Large tree down on South Bend Rd.
Polo (Ogle County): 3" of rainfall with standing water several feet deep in some areas.  --TS

Storms moving through

7:00pm Update:  Storms winding down this evening but more could be on the way Wednesday. 

Heavy rain continues to fall across Winnebago County.  Flood Advisory for Boone, Green and Rock Co.  Rainfall rates could reach 2" per hour!

3:45pm Update: Storms will continue to rapidly develop across northern Illinois and southern Wisconsin through the late afternoon.  Any one of these storms will be capable of producing heavy rain, hail and damaging winds.

3:45pm: 0.25" hail being reported in Rochelle in Ogle Co near the intersection of Flagg and Brooklyn Roads
3:36pm: 58 mph wind gust at the Chicago/Rockford Int'l Airport

3:30pm: Strong thunderstorms continue to move into southern Green Co. in southern Wisconsin this afternoon.  Doppler radar beginning to indicate the possibilty of large hail with this storm just south of Monroe.  Storms will continue to move north very slowly through the afternoon.  Watching a few more on the radar just south of Rockford and in Carroll Co.

Watching the Radar

Watching one storm just north of Belvidere this afternoon that has been sitting over the same spot.  Heavy rain, lightning and strong winds can be expected with this storm. 

(1:22:48 PM) nwsbot: LOT: Rockford [Winnebago Co, IL] broadcast media reports HAIL of pea size (E0.25 INCH) at 01:15 PM CDT -- near downtown rockford.

1:00pm Update:  Severe Thunderstorm Watch may be needed this afternoon as storms continue to develop in an unstable airmass. 
12:45pm Update: Storms will continue to develop through the afternoon and evening.  Storms that do develop will produce heavy rain, lightning, gusty winds and possibly hail.  Storms beginning to develop just southeast and east of the Rockford metro area this afternoon and will move north/northwest.  Also watching some storms in Dubuque Co, Iowa that may clip the western part of Jo Daviess County within the next hour or two.

Storms will continue to fire through the afternoon thanks to outflow boundaries from storms earlier this morning in Iowa - as we're already starting to see them develop in eastern Iowa early this afternoon.  While we're not looking at any too severe today, any storms that do develop will have the capability to produce gusty winds, heavy rain and hail.  Going to keep the thunder wording in the forecast tonight and Wednesday as a weakening cold front moves through during the late afternoon/evening hours.

Thunderstorms Moving through for Some

9:35am Update:  Storms will continue to diminish through the morning hours, but we are watching one storm near Amboy.  Watch for heavy rain, frequent lightning and possibly hail as this storm continues to move very slowly to the northwest.

We'll continue to see sunshine as we go through the morning and into the afternoon.  Any boundaries that are left over from this morning could produce more storms through the afternoon. 

6:30am: Thunderstorms continue to move slowly to the west/northwest this morning thanks to a couple of outflow boundaries left over from storms last night.  The first boundary is moving in from the east from Lake Michigan (the storms we were seeing this morning), the second is a boundary moving through Iowa currently from storms left over in the Plains.  You can see by the radar image how quickly these storms "pop up" because of all the heat and humidity.  This will be the trend as we go through the morning and into the afternoon.  Since there is really nothing to push the storms through, heavy rainfall and frequent lightning will be the primary threat.

Monday, May 24, 2010

Record High Tied at Rockford Airport

Rockford hit a high temperature of 93 degrees today. That was hot enough to tie a record high set back in 1921! Here are some other toasty numbers from across the area:

Freeport: 95
Rochelle: 93
Sterling: 93
DeKalb: 89

The heat will subside a little bit on Tuesday, although it will still be very warm and humid. Highs will be in the upper-80s most areas, with an isolated afternoon thunderstorm possible. Storms will grow increasingly likely as we head through Wednesday and into Thursday morning as a weak cold front slowly begins to push across the area. Until then, stay cool out there!  --TS

Nearing Record Warmth Today

It's going to be another hot and humid afternoon with temperatures pusing 90° once again today.  Sunday we topped off right at 90° and today we may be just a little warmer.  While Sunday's record high wasn't in jeopardy, today we may be pushing it.  The record high for today is 93° set back all the way in 1921.  We'll be close, but I think one thing that may hold us back will be the dew points.  The higher the moisture is in the atmosphere, the harder it is for the temperature to warm.  We'll have to see!  Either way it's going to be a hot one today!

Sunday, May 23, 2010

An Extended Period of Very Warm Temperatures

An upper level ridge is situated over the eastern part of the USA, and a trough of low pressure is over the western part of the country.  With the ridge in place over the next several days, the very warm conditons will continue through Thursday.  There will be lots of low level moisture in place for most of the week, so the combination of heat and humidity will serve to make it uncomfortably warm for most people.  There is lots of low level moisture, but it is not very deep, so no widespread heavy thunderstorm activity is expected this week.  There may be some isolated thunderstorms on Monday, and some scattered thunderstorms on Tuesday.  On  Wednesday and Thursday there could be some more isolated thuderstorms.  On early Friday morning a backdoor cool front will slip southward out of Wisconsin across northern Illinois.  The moist air will be pushed southward by the cool front, and temperatures will be knocked down a few degrees under sunny skies with cooler Canadian air moving into the Stateline.  High temperatures on Friday, Saturday, and Sunday will be in the upper 70's to low 80's.
By Meteorologist
Eric Nefstead

Saturday, May 22, 2010

The Hottest Weather So Far...

The season's first heat wave is about to settle into the Stateline. Temperatures will seem more like July than late May for the next few days. There will be lots of sunshine along with increasing humidity. This will make for some isolated afternoon thunderstorms beginning on Monday aftternoon. That same pattern will continue thru Thursday with plenty of sunshine, warm temperatures and those isolated afternoon thunderstorms. Temperatures will top out around 90 Sunday and Monday, and continue well into the 80's during the afternoon's for the entire week.
By Meteorologist
Eric Nefstead

Friday, May 21, 2010

Good 'ole humidity

With the warm up expected late weekend/early next week, wanted to talk a little more about humidity.  It's been a while since it has felt "muggy" outside and I think we will get our first dose Sunday afternoon.  Water molecules (vapor) are all around us; we can't see them, but they're there.  Temperature and dew point play a role in what the relative humidity is.  The higher the dew point (and relative humidity), the more discomfort you feel.  The reason: the more moist the air is, the larger the resistance of moisture loss (and therefore to heat loss due to evaporation) from the human body to the air, because the air is closer to its saturation point.  Think of it as, when you get out of the shower you often times feel cool because evaporation is a cooling process.  But, have you ever gotten out of the shower on a humid day when maybe your a/c wasn't working and you just couldn't seem to dry off?  That's because the water doesn't evaporate as quickly as it would normally, making you feel uncomfortable and sticky.  Dew points are expected to rise into the 60s through next week and whenever dew points reach those values the air begins to feel just a little more humid.

Thursday, May 20, 2010

Heat Wave Coming!

It's only mid-to-late May, but it's going to feel more like mid-July by the second half of the weekend! A big ridge of high pressure will set-up it's office in the mid-section of the country and hang-out through the majority of the coming week. Beneath this ridge, the air will sink and heat by compression into the upper-80s or hotter! In fact, our global model is predicting a high of 90 degrees both Sunday and Monday.

Be sure to wear sunscreen and drink lots of water (not alcohol) if you're going to be spending extended periods of time outdoors this coming week. 88 to 90 degrees might not seem too terribly hot, but it's been awhile since we've seen those types of highs around here and most people probably aren't used to it. In fact, the last time we saw highs in the upper-80s was June 27th, 2009 when we hit 89 degrees.

Rain Moving In

Rain is moving in a little quicker than first thought this morning.  Already seeing some showers south of I-88 as of 4pm.  Look for rain to begin to move into the Stateline around 6pm.  Any plans on heading out tonight, you'll want to pack the umbrella and jacket.

Warm Up in the Making

It will feel a little more summer-like through the end of the weekend and into next week.  Once we get past the storm system slated for tonight and Friday, a ridge of high pressure will begin to build and allow temperatures to warm into the mid 80s by next week!  Saturday will be more of a transition day, with clouds hanging around and tempertures in the mid 70s.  The high will hold steady through Tuesday and then start to break down some as a trough begins to shift east allowing storms to develop midweek.

Wednesday, May 19, 2010

Water Skiers on the Rock River!

Today was a beautiful day along the Stateline. So nice that someone tried water skiing along the Rock River! (Our Skytrack cam caught the action in-between shows this afternoon.) Hopefully they had a wetsuit on as water temperatures are probably only in the 50s or low 60s at this time! (If you do come across any websites that have water temperatures for the Rock River, let us know.)

Water temperatures will probably have a chance to warm-up a little over the next week. Friday looks like the only cool, damp day out of the next seven. Otherwise, highs will warm into the 80s by Sunday and lows should be in the lower or middle 60s!  --TS

Large Sinkhole on I-24 in Tennesse


A large sinkhole has developed along I-24 eastbound at the Coffee-Grundy counties line. As a result, the eastbound lane had to be closed by the Tennessee Department of Transportation.

According to Jennifer Flynn, with TDOT, the sinkhole is approximately 25 feet deep, 40 feet long and 18 feet wide.
Read the full story here.

Thanks Central School!

A big THANK YOU  to the 2nd graders at Central School in Rochelle, IL for inviting me to come to their class and talk all about weather.  We had a great time and they all had very interesting questions!   There were three 2nd grade classes combined: Mrs. Ebert, Mrs. DaCosta and Mrs. Lieving

Thanks again!

Tuesday, May 18, 2010

NOAA: Warmest April Global Temperature on Record

According to NOAA's National Climatic Data Center (NCDC), the combined global land and ocean surface temperature was the warmest on record for the month of April and for the period from January to April.  Additionally, April's average ocean surface temperature was the warmest on record for any April and the global land surface temperature was the third warmest on record!

Highlights of the global temperature anomalies:

-The combined April global land and ocean average temperature was the warmest on record at 58.1°, which is about 1.37° above the 20th century average.  The previous record was set back in 1998!
- The warmest anomalies during the month of April occurred in southern Asia, northern Africa, the north central and northeastern US, Canada, Europe, and parts of northern Russia.  Cooler than average conditions prevailed across Argentian, Mongolia, eastern and southern Russia and most of China.
- This was the 34th consecutive April with average global land and ocean temperatures above the 20th century average.  The last April with below average temperatures occurred in 1976!
- The El Nino Southern Oscillation (ENSO) did weaken in April, although the temperature anomalies across the equatorial Pacific Ocean remained above 0.9°F.  The weakening contributed significantly to the warmth observed in the tropical belt and the warmth of the overall ocean temperature for April.  According to the Climate Prediction Center, a transition to ENSO neutral conditions is possible through June with some indications even pointing to a transition to La Nina conditions into the upcoming winter.

Highlights of January-April Global Temperature Anomalies:
- Temperature anomalies for the first four months of the year were very warm over much of the world's surface, especially in Canada, northern Africa, South Asia and a majority of the tropics.  Cooler than average conditions prevailed across the higher-latitude southern oceans, the Gulf of Alaska, the western South American Coast, Mongolia, northern China, the southern US, northern Mexico and much of Europe and Russia.
- The Northern Hemisphere land and ocean temperature during January-April 2010 was the third warmest on record.  The Southern Hemisphere land and ocean temperature was the second warmest, behind 1998.
- January-April was the 34th consecutive year with above average temperatures.  The last January-April with below average temperatures occurred in 1976!

You can find more information by clicking on the  National Oceanic and Atmospheric Administration's  website.
image courtesy: NOAA

Monday, May 17, 2010

Where's the Warmth? Head North!

It has been a rather cool start to May along the Stateline, and today was no exception. On a day when our average high is 72, Rockford topped-out at a modest 65 degrees. A chilly, slow-moving area of low pressure moving across Indiana and Ohio today kept us in a northeasterly flow regime. And it was cooler close to Lake Michigan... Chicago's O'Hare Airport only hit 58 degrees for a high with overcast skies and a little bit of light rain.

I was actually on the phone with my parents -- who live in the Upper Peninsula of Michigan -- a little while ago. They said it was a beautiful day up there, and that it was probably warmer there (about 290 miles NNE of Rockford) than it was here. Sure enough, I checked the daily climate report from Negaunee, MI and the high there today was 73. High pressure centered over Lake Superior actually gave much of the Upper Great Lakes region a warm day. It was 74 degrees in Duluth, MN, 75 in International Falls, and 78 in Grand Forks, ND today!

Sunday, May 16, 2010

There Won't be Much... Rainfall that is...

Skies will remain mostly cloudy overnight, and continue to be mostly cloudy on Monday. A disturbance passing well to the south of the Stateline will put our area on the northern edge of it's precipitation shield later tonight through late afternoon on Monday. Dry air continues to feed into northern Illinois from the northeast, and it is eroding precipitation as it comes in from the southwest. Radars are showing precipitation over northwestern Illinois and southwestern Wisconsin. Most of it is virga. Virga is precipitation that evaporates before it reaches the ground. As we go through the evening, dew points are expected to rise a few degrees, and that should allow some of the precipitation to reach the ground. It will be mostly cloudy and sprinkley on Monday. Any light rain that falls is expected to end by 6 pm on Monday evening as the are of low pressure causing the rain moves slowly off to the east. Weak high pressure will begin to take control, and with some strong May sunshine on Tuesday, temperatures will recover to near 70 degrees in the afternoon. A warming trend with lots of sunshine will be the weather senario for the rest of the week, with temperatures edging up a couple of degrees each day, and by the weekend it will be close to 80 degrees.
By Meteorologist
Eric Nefstead

Saturday, May 15, 2010

A "dirty" high pressure over the Great Lakes will move slowly eastward on Sunday.  There is a southwesterly flow over the top of the high accounting for high level clouds over the weekend.  Temperatures will remain a little bit on the cool side because of the continued cloud cover from Sunday through the early part of the week. A disturbance moving out of the southern plains on Sunday could scatter some showers into the area on Sunday evening.  It will pass well south of our region on Sunday night, but there will be enough of a moisture feed in from the south that showers will be likely after midnight, and enough instability may be in place to cause some rumbles of thunder.  The low will stall out over southern Indiana, and we will have a continuing chance of showers on Monday, and some may even pop up on Tuesday. By Wednesday high pressure will be in firm control of Stateline area weather, and a warming trend will begin, and continue right into next weekend.  Temperatures will be well into the 70's by late in the week under the influence of a southerly breeze and mostly sunny skies.
By Meteorologist
Eric Nefstead

Friday, May 14, 2010

Rainfall Record

Rainfall totals Thursday were pretty impressive across the Stateline and actually broke the record for the amount of rain in one day in Rockford.  The old record for rainfall was 1.50" set back in 1978.  Yesterday we received 1.74".  Looking back at the past three days, we received almost 3.50" pushing our monthly precipitation total to 4.18", which is 2.59" above average!  So, I think we'll be set on rainfall for a little while!

Thursday, May 13, 2010

Some Rain Tallies

Did we ever get a lot of rain in a relatively short period of time! Rockford got 2.47" of rain since last night! Half of that total -- about 1.24" -- fell between 2 and 4:00 this morning. Due to the continued run-off, the entire viewing area is under a small stream flood warning through 10am Friday. Here are some other rain totals across the area:

Marengo: 3.35"
Galena: 3.33"
Byron: 3.01"
Belvidere: 2.90"
Stockton: 2.79"
Oregon: 2.78"
Shabbona: 2.60"
DeKalb: 2.41"
Roscoe: 1.96"
Monroe: 1.62"
Beloit: 1.37"
Steward: 1.23"

Fortunately, we'll have some time for the rain to soak-in just a bit. Our next chance of rain doesn't get here until late Sunday.  --TS

Rainfall Update

10:45am Update: 24 hour rain totals so far this morning

Rain will continue on and off through the morning hours.  So far looking at rainfall totals averaging close to 3 inches in some locations!  Be careful for localized flooding and ponding on roadways and streams/creeks rising.  If you have any pictures or rainfall amounts, we would love to see them.  You can send them to!

Storm Update


(9:07:10 AM) nwsbot: DVN: 4 Ne Freeport [Stephenson Co, IL] trained spotter reports HEAVY RAIN of M2.75 INCH at 09:05 AM CDT --

(7:34:16 AM) nwsbot: LOT: 3 Nnw Dixon [Lee Co, IL] trained spotter reports HEAVY RAIN of M2.73 INCH at 07:00 AM CDT -- 24 hour total. cocorahs observer.

(7:34:16 AM) nwsbot: LOT: Genoa [Dekalb Co, IL] co-op observer reports HEAVY RAIN of M3.24 INCH at 07:00 AM CDT -- 24 hour total

(7:27:20 AM) nwsbot: DVN: 6 Sse Council Hill [Jo Daviess Co, IL] trained spotter reports HEAVY RAIN of M3.50 INCH at 07:26 AM CDT -- 2.75 inches in the last 12 hours.

(7:17:45 AM) nwsbot: LOT: Rockford [Winnebago Co, IL] asos reports HEAVY RAIN of M2.41 INCH at 07:00 AM CDT --

(6:56:08 AM) nwsbot: DVN: Stockton [Jo Daviess Co, IL] co-op observer reports HEAVY RAIN of M2.79 INCH at 06:55 AM CDT -- 24 hour rainfall total.

(6:37:40 AM) nwsbot: DVN: Galena [Jo Daviess Co, IL] co-op observer reports HEAVY RAIN of M3.33 INCH at 06:36 AM CDT -- storm total since yesterday.

(6:16:41 AM) nwsbot: LOT: Dixon [Lee Co, IL] airplane pilot reports FLASH FLOOD at 06:10 AM CDT -- law enforcement reports flooding still ongoing with high standing water in many locations.

(5:36:56 AM) nwsbot: LOT: Woodstock [Mchenry Co, IL] co-op observer reports HEAVY RAIN of M1.96 INCH at 05:30 AM CDT -- 24 hour total of 1.96 inches. standing water in fields.

(4:58:28 AM) nwsbot: LOT: Rockford [Winnebago Co, IL] co-op observer reports HEAVY RAIN of M2.31 INCH at 04:55 AM CDT -- measured since 7pm.

(3:29:10 AM) nwsbot: LOT: Dixon [Lee Co, IL] trained spotter reports FLOOD at 03:00 AM CDT -- six to eight inches of water at the intersection of illinois route 2 and willett avenue.

(3:29:11 AM) nwsbot: LOT: Dixon [Lee Co, IL] trained spotter reports FLASH FLOOD at 03:20 AM CDT -- river road closed one half mile east of galena avenue with a car stranded in flood water up to the bumpers.

Heavy rain continues to come down across much of the Stateline this morning with the heaviest hugging I-39.  Radar rainfall estimates so far have indicated at least two inches of rain has fallen in some spots.  Rain, heavy at times, will continue through a good part of the morning.  Surface low has moved a little further to the northwest and that has allowed the axis of heaviest rain to form right along northern Illinois/southern Wisconsin.  As a result, Flash Flood Warnings have been issued for Winnebago, Ogle, Lee, Boone, DeKalb and McHenry Co. until 8:15am.  A long line of convection stretches just south of the Rockford Metro area down through west central Illinois as of 3:30am.  While the entire rain shield will slowly move to the east through the morning hours, several rounds of heavy rain will be likely in some locations.  After the rain moves out, our next focus will be the cold front as it moves through later in the day.  Any type of sunshine/daytime heating could potentially allow the atmosphere to destabilize some with more storms possible late in the afternoon.  We'll continue to monitor trends through the morning hours.

Wednesday, May 12, 2010

Flood Watch/Flash Flood Watch

The National Weather Service office out of the Quad Cities has issued a Flash Flood Watch for Stephenson county through 7am tomorrow. This means brief, heavy downpours may produce localized flooding in some areas of Stephenson county. The National Weather Service office in Chicago has issued a Flood Watch for Winnebago, Boone, Ogle, Lee, and DeKalb counties from 1am Thursday morning through 11pm that night. This means that moderate to heavy rainfall over a prolonged period may cause local rivers and streams to overflow their banks. Expect over an inch of rain by tomorrow afternoon in most areas, while some spots may locally see 2-3" of rain.  --TS

Watching the Radar

With the warm front running south through southern Illinois, temperatures this morning have had a hard time rising much above the upper 40s this afternoon.  The front will gradually begin to work its way north through the late afternoon/evening hours and into the Great Lakes overnight.  As it does, moisture will continue to stream in across the Mississippi River Valley with showers and thunderstorms becoming more widespread overnight.  There are a couple things we will have to watch as we go through the afternoon.  One, the placement of the front.  There is the potential for heavy rain once again through the overnight and into Thursday morning.  The second, storm development to the south.  If storms fire along the front this afternoon, they may actually take away some of the moisture needed to provide some of the heavier showers overnight.  With the already saturated ground in some parts, especially to the southwest, Flash Flood Watches have been issued for counties just south of the WTVO viewing area.  We'll keep an eye on things this afternoon.  Flood watches may need to be issued as we go into the evening.  Either way, it will be a soggy start to Thursday.

Tuesday, May 11, 2010

Slight Risk of Severe Storms Wednesday Night

An active southwest to northeast flow in the upper levels of the atmosphere continues to send a train of low pressure areas through the central Plains and into the Great Lakes region. Another low in central Colorado as of this writing will quickly move to the east and then northeast on Wednesday. An approaching warm front Wednesday night will trigger some showers and thunderstorms across the Stateline. According to the Storm Prediction Center out of Norman, OK, there is a slight risk that some of these storms will be severe in Ogle, Lee, and DeKalb counties. We'll be watching this situation as it unfolds!

Tom Skilling Chases Tornadoes

WGN-TV's Chief Meteorologist Tom Skilling was out in the field Monday where he witnessed his first ever tornado.  Unfortunately, they quickly learned that they were the ones being chased!  He also provides a scientific look into why we are tying to better understand how these storms form and how chasers can help in the field.  Video courtsey WGN-TV



Rainfall Totals this Morning

Rain will continue through the next hour or two before completely moving out of the WTVO viewing area by this afternoon.  Clouds will stick around through a good part of the day with a little bit drizzle.  Doppler estimated rainfall amounts through 9am have much of Northern Illinois picking up on close to an 1" of rain over the past 24 hours, with a few locally higher amounts.  Southeast Iowa has once again received close to 2" of rain with this last system.  While we will see a break in the rain later tonight and for the first part of Wednesday morning, we could get another round of heavy rain Wednesday night into Thursday morning.  By the time it's all done, some may be looking at close to 2"-2.5".  The nice thing about the rain that moved through this morning is that it was a good soaking rain.  Most of the local farmers have a lot of the corn planted, with some of it beginning to come up, and are now working on the beans.  The rain that we could potentially see with the next system shouldn't have too much of an impact other than farmers getting out into the fields.  The one thing we don't want to see is and inch of rain in an hour!
Some other local rainfall reports from the Stateline:

3 S Oregon: 1.38"
1 WNW Morrison: 1.30"
Bob in Kingston: 1.00"
Ken in Rochelle: 0.93"
Rockford Airport: 0.84"
Freeport: 0.82"

Severe Weather Rips through the Plains

It was a significant severe weather day for parts of Oklahoma and Kansas Monday afternoon.  At least 5 fatalities are being reported along with numerous injuries.  The National Weather Service issued 70 tornado warnings, 31 of which came from the office in Norman, and 88 severe thunderstorm warnings!  There were 37 preliminary reports of tornadoes through Kansas and Oklahoma, but a final count will be conducted by the National Weather Service within the next couple of days.

From the National Weather Service in Norman, OK....

The National Weather Service is in the process of compiling information on the tornado outbreak.  Here are some things that we know, and some important things to remember:

- As a result of the the widespread nature of the outbreak, it will take some time to sift through all the data and reports.  Bear with us as we attempt to provide the most complete picture of the events that occured.
- We do NOT have a count of the total number of tornadoes at this point.  That will take a complete survey analysis to determine.
- Storm survey teams will be out surveying some of the damage on Tuesday, May 11th.
- The possible tornado damage paths are spread over a north-south area of over 200 miles from near the Kansas-Oklahoma border to near the Red River.
- Very large hail was reported in several locations, up to the size of softballs (4.25")

Monday, May 10, 2010

Cooler Start to May

So far the weather has been a little closer to average in the 5th month of 2010. Temperatures are just a fraction of a degree below average through May 10th. This is a big change from April when temperatures averaged 6.9 degrees above average. That's a big departure from normal for an entire month... In fact, St. Louis, MO averages about 7 degrees F warmer than us in April. So we had weather more typical of eastern Missouri than northern Illinois!

The more seasonal May weather will continue for us. In fact, it looks colder than average for a change for most of this week with the potential for some heavy rain both Tuesday morning and Thursday.

Stormy in the Plains; Rainy in the Great Lakes

We are going to be getting into a more active weather pattern over the next couple of days, beginning tonight and lasting through Thursday evening. Two storm systems will be impacting the Stateline with the first moving through tonight and the second Wednesday night. While high pressure over the northern Great Lakes will dominate our skies through the morning and even into the afternoon, a very strong storm system will begin to spin through the southern Plains later today. A very strong jetstream moving out of the southwest, combined with the surface low and copious amounts of gulf moisture will lead to a potentially dangerous situation through parts of central Oklahoma and southeast Kansas. A high risk for severe weather has been outlined by the Storm Prediction Center for this afternoon and evening. For us, the low will begin to move into Missouri later this evening and overnight keeping the warm front to the south. Moisture will begin to ride over the warm front providing enough lift to keep a few heavy showers going by Tuesday morning. We could also see a few thunderstorms as well. That system will depart by Tuesday night just in time for our next one to move in by Wednesday. As of right now, this one looks to follow almost the same path as the first keeping a heavy rain scenerio across the Stateline into Thursday morning before the cold front moves through by Thursday evening. Looking at some of the rainfall total forecasts this morning, some are highlighting over 2" by Thursday morning. Of course, this could change as I have seen it do many times. But the potential is there for someone to end up with a lot of rain!

Sunday, May 9, 2010

An Active Week for the Stateline....

Cold Canadian high pressure which caused frost last night is shifting to the east tonight.  Clouds will be a factor ovenight, and keep temperatures from dropping any lower than the middle to upper 30's, so frost should not be a problem tonight.  A new area of low pressure will kick out of the central Rockies into plains on Monday, and will move to central Kansas by supper hour on Monday eve, and could bring scattered showers to the Stateline during the afternoon on Monday. A soaking rain will  occur on Monday night with some rumbles of thunder.  Rainfall totals with this system could be around 1" across northern Illinois, and more than that is expected across southern Wisconsin.  On Tuesday there could be some lingering showers and thunderstorms as the front associated with that system edges slowly to the southeast.  Tuesday night will be dry, and so will Wednesday morning, but by Wednesday afternoon the front will start to move back toward the north, and moisture overrunning the front could scatter some showers and thunderstorms back across the Stateline in the afternoon.  The low pressure associated with that system will approach the area on Wednesday night, and could bring some locally heavy rainfall to northern Illinois.  Stay turned to WTVO 17 and WQRF Fox 39, and our weather team will keep you posted all week as these systems move through the area.
By Meteorologist
Eric Nefstead

Saturday, May 8, 2010

It's the 9th of May on Mother's Day, and the Day Starts with Frost!

FREEZE WARNINGS for northwestern Illinois, and FROST ADVISORIES for the rest of the are extend from 3am Sunday night until 8 am Sunday morning.  A ridge of Canadian high pressure extends from Canada through a center over Fargo, North Dakota through Iowa through another center in nothern Missouri, and then southward into the lower Mississippi River Valley as midnight Saturday night.  The Stateline lies just east of  the ridge with drier air dissipating the stratocumulus clouds that were across the area all day on Saturday.  With clearing skies, light winds and lower dew point air moving in from the northwest, frost will form in the overnight, and become widespread after 3 am persisting through daybreak on Sunday.  This frost event is likely to cause damage to the most vulnerable  sensitive annual garden vegetables and flowers.  If you have not covered them up, you may have to replant.  You will be able to tell by late morning the extent of the damage.  The strong May sun will boost temperatures rather rapidly on Sunday morning to comfortable levels by the noon hour.  It will be a very pleasant afternoon with some high level cirrus filtering the sunshine a bit with temperatures in the low 60's along with light winds.  The high pressure will shift off to the east on Sunday night as the next weather system to affect the Stateline develops over the plains.  Winds will become southeast on Sunday night, and continue southeasterly on Monday. with a warm front approaching from the southwest, moisture overrunning the front will cloud skies over  on Monday, and may scatter some showers into our region on Monday afternoon.  Significant rains are possible Monday night into early Tuesday as the warm front and assoicated low pressure storm center move across Illinois.  That is the first of two sytems that will move though the area next week.  Another system has the potential for producing some more heavy rains on Thursday night.  Stay tuned.
By Meteorologist
Eric Nefstead

Friday, May 7, 2010

Rainfall Amounts

Some needed rainfall moved across the stateline this morning. Here are some reports:

Sterling: 0.86"
O'Hare: 0.73"
Rockford: 0.68"
Rochelle: 0.60"
DeKalb: 0.38"

A few stray showers are possible behind a departing area of low pressure overnight and Saturday morning. Otherwise, expect a dry weekend with our next chance of rain coming on Monday night.  --TS

Temperatures Tumble

It's no surprise that the month of April was a warm one.  Even the beginning of May has started off pretty mild.  Unfortunately, that will be changing over the next couple of days.  Thursday's high was right at average with temperatures topping off at 68°.  Temperatures through the weekend will run about 10° below average with highs on Saturday only reaching the mid 50s!  We may continue to see temperatures a little on the cool side throughout the month of May and then really start to warm things as we get into summer.  I guess time will time!

Rain Almost Done

The heaviest of the rain now beginning to move to the east this morning as the low begins to pull into central Illinois.  Most locations across the Stateline have picked up between three quarters inch to one inch rainfall.  Some impressive rainfall amounts out of Van Buren Co. in Iowa and Henderson Co. in western Illinois of amounts close to 3"- 3.50"!  A few wrap around showers could linger throughout the afternoon.  Actually starting to see some clearing to the southwest in the cloud cover.  But I think we'll remain mostly cloudy through the day.

Thursday, May 6, 2010

Uh oh - it's the four letter "S" word again!

....hopefully not for us, though!  Temperatures this weekend will fall below average not only here but all across the Great Lakes with our next storm system.  When I was looking at the model guidance this morning I didn't feel too bad about the cooler weather and rain in the forecast because it could be a lot worse!  With the cool air that will be pulled into the low, parts of northern and central Wisconsin could pick up on a little snow Friday night as temperatures cool into the low 30s!  While we are done with average montly snowfall totals, parts of Wisconsin can still average a "trace" of snow into May.

Wednesday, May 5, 2010

WTVO Loses Power

If you caught the 6pm news tonight, you may have noticed the screen in front of you suddenly go black and/or heard some sudden static. That's because we briefly lost power here on the far west side of Rockford! The outage didn't last long, but it did interrupt our newscast.

The question everyone around here is asking now is whether the wind caused it. The highest gust I saw on the RFD hourly observations was 37mph. There may well have been a stronger gust in-between hourly observations, but I'd still be somewhat surprised if winds of this magnitude were strong enough to knock down a powerline.

Regardless, it looks like the wind will die-down tomorrow and we should enjoy plenty of sunshine. More wind, however, is expected Friday night and Saturday.  --TS

Tuesday, May 4, 2010

Cold Front Coming At Wrong Time for Severe Weather

A cold front will move through the stateline overnight with showers and perhaps a rumble of thunder. But the severe weather they had north of us into central Wisconsin won't hold-together when the front moves through here. (In fact, the severe weather is already ending as of this writing.) If this cold front were coming through during the peak heating of the afternoon, severe weather would be more of a concern. But since it's coming through overnight when the atmosphere is more stable, we'll probably just see some showers and a few rumbles of thunder. (Also, we don't have a lot of moisture at the surface to fuel severe storms.)

By the way, that severe weather in central Wisconsin really was! A tornado touched down in Winnebago County (which is near Osh Kosh), and there were funnel cloud sightings south and east of Green Bay. And strong winds in Waupaca downed a tree.  --TS

Few rumbles to the north

Our weather pattern remains fairly quiet, but active for some across the US.  The jetstream remains in more of a zonal flow with storm systems tracking across much of the northern tiers of the US.  Strong winds in the jetstream will push a low pressure system through the northern Plains and into the northern Great Lakes by this afternoon.  As it does, a warm front will continue to lift off to the north through the afternoon with a trailing cold front sweeping through later this evening and overnight.  A few showers/rumble of thunder may be possible through the night before the front passes Wednesday morning.  Stronger storms will be likely into north-central Wisconsin and back through Iowa closer to the main area of low pressure.  Daytime heating and moderate instability will allow some of the storms to produce gusty winds and hail through the afternoon hours. 

Monday, May 3, 2010

Yet Another Dry Month

All four months of 2010 have been drier than normal in the Rockford area. We've seen 5.84" of precipitation (including melted snow) so far this year, which is 3.30" below our normal-to-date value of 9.14". April continued along this same trend-line of below normal precipitation. We had 2.89" of rain in April 2010... nearly 3/4 inch below our average value of 3.62". Although the warm, dry weather might feel nice, it's obviously bad news for farmers and for fire danger. There is hope for rainfall this coming week with chances of rain in the forecast for Wednesday, Friday, and Saturday.  --TS

A couple rumbles here and there

With a weak disturbance passing through this afternoon, there will be just enough instability to get an isolated thunderstorm during the afternoon/early evening hours.  The main threat for any severe weather looks to remain east and south, but a thunderstorm or two can't be ruled out across the Stateline.  Once the sun sets, any storm activity should diminish and leave partly cloudy skies overnight.

Fourth Warmest April

If you thought it was a little extra warm during the month of April, you weren't alone!  The average montly temperature for Rockford was 54.8°, making it the fourth warmest April on record!  Records date back to July 1906.  Looking back at the last ten years, April 1915 holds the record for the warmest average temperature of 56.3°.  So, what does this hold for the upcoming summer.  According to the Climate Prediction Center above normal temperatures are possible for parts of the Western US, Alaska and parts of the Southeast.  Below normal temperatures are possible for portions of the Great Plains while equal chances for above or below normal temperatures are possible for the Great Lakes.

Sunday, May 2, 2010

A Little Cooler Monday

A front has been pushing across the upper midwest on Sunday. By Sunday evening it was approaching the Stateline, and was generating showers, and some thunderstorms over eastern Iowa. Those storms produced some quarter inch hail just west of the Mississippi River. By the time the precipitation reached northern central Illinois it dissipated into light rain. It will end by 1 am. With relatively cold unstable air aloft, and a continuing southwest upper air flow, showers and thunderstorms will pop on Monday afternoon.  They will end quickly as the air stabilizes in the evening.  Warmer air will move in under mostly sunny skies on Tuesday boosting temperatures into the middle  70's by late afternoon.  A series of systems moving across the midwest from Wednesday through Friday with generate several periods of showers and thunderstorms.  Some fairly significant amount of more than 1" may add up by Friday night.  Progressively colder air will bring a noticable cooling trend to the area  by late week, and into the early part of next weekend.
By Meteorologist
Eric Nefstead

Saturday, May 1, 2010

Stalled System Tonight...Sunday Afternoon Looks Good

The cold front that generated severe weather on Friday afternoon, and evening has pretty much stalled out this evening.  It stretches from a vertically stacked large upper low over Lake Winnipeg in Manitoba Provience, Canada across Lake Superior, western lower Michigan, southwest to near St. Louis, to southwest Arkansas, to a surface low over Texarkana, and then southwest to the lower Rio Grande Valley.  The front pretty much parallels the upper jet stream.  A mid level disturbance over Texas will get caught up in the northeast flow overnight, and enhance the surface low as it moves across Arkansas and Missouri through east central Illinois by morning.  A band of precipitation has developed in association with this system from Oklahoma, across Missouri, and western Illinois into the north central Illinois area.  Within that band, an area of thunderstorms has developed from extreme northeastern Oklahoma though Missouri to just south west of Quincy, Illinois.  As the entire system moves northeast tonight, enhanced by a 50 knot low level jet, precipitation will overspread the entire Stateline region by late evening.  Conditions appear to be too stable in this area to be able to  to support any thunderstorm activity.  It looks as if any thunderstorms that do occur, will be well off to our southeast.  Rain will be likely from late evening until 4 or 5 am in the morning.  Right now it appears as if it will be mostly light rain, but totals by morning may be a quarter of an inch in some areas.  The rain will scatter on out during the early daylight hours on Sunday, and should be all finished by late morning leaving the day partly sunny with warm afternoon temperatures reaching the low 70's once again.  The large upper low over Manitoba will move slowly into western Ontario on Sunday, and spin a trough of low pressure southeast across the northern plains reaching the Stateline overnight on Sunday night.  Although, this does not appear to be a moisture rich environment, it does look to be quite unstable with some very cold air aloft, so, again showers will probably develop overnight on Sunday with even the possibliity of some thunderstorms over southern Wisconsin.  Any scattered light showers remaining on Monday will not amount to much.  A warm front will push back northward  across the area on Tuesday taking temps back into the low 70's again. No precipitation is expected because of limited moisture availability.  Another front will move through the area on Wednesday with very little affect on the weather.  That front will stall out near the Ohio River Valley on Thursday as the upper flow becomes more westerly, and disturbances moving from west to east across the plains to the north of the front cause showers and thunderstorms to break out in our area from Thursday into Friday.  A push of colder air from Canada will end the precipitation on Friday night. In fact, it may be cold enough Friday night for some patchy frost over parts of southern Wisconsin, with low temperatures below 40 degrees.  Next weekend looks like it will be dry at this time.
By Meteorologist
Eric Nefstead