What's up with the fog?

A Dense Fog Advisory will continue through noon today for almost all of southern Wisconsin and northern Illinois.  Low level moisture has been very slow to leave the past couple days and now that high pressure has moved into the upper Midwest winds have remained fairly calm and we haven't been able to mix our atmosphere very well.

This is the upper level sounding (snapshot of the atmospheric profile) from Davenport, IA this morning.  The red line indicates temperature and the green line indicates dew point.  On the right hand side is the wind, both the direction the wind is coming from and the speed of the wind.  Notice how the temperature and dew point line are almost on top of each other in the lowest levels of the atmosphere.  This shows a very saturated layer.  Also, notice how the temperature line increases with height.  The temperature readings are on the bottom of the graph and in Celsius.  Just like yesterday morning, there is an inversion in our atmosphere and with very little wind and light wind speeds we won't be able to bring down the drier air from above and this is probably going to keep the fog around for a little while.  This will also keep temperatures down today as we've been stuck at a chilly 29° the past several hours.  Once the fog does lift we won't see much sun today thanks to cloud cover overhead.

Dense Fog Again Tonight

Visibilities are already less than 1/2 mile in Freeport this evening, and the NWS Quad Cities has issued a Dense Fog Advisory for northwestern Illinois until noon tomorrow. Green and Rock counties in Wisconsin are also under a Dense Fog Advisory until noon. We'll continue to watch for an advisory from the NWS Chicago for the rest of our counties, and let you know if they issue one. In the meantime, drive with your low-beam headlights tonight and tomorrow and watch for slick spots on bridges and overpasses.

URGENT - WEATHER MESSAGE
NATIONAL WEATHER SERVICE QUAD CITIES IA IL
606 PM CST THU FEB 2 2012

...DENSE FOG BECOMING WIDESPREAD...

DENSE FOG WAS BECOMING WIDESPREAD ACROSS PORTIONS OF EASTERN IOWA AND NORTHWEST ILLINOIS EARLY THIS EVENING. THE FOG SHOULD CONTINUETHROUGH THE NIGHT AND FOR MUCH OF FRIDAY MORNING. VISIBILITIES WILL FREQUENTLY BE 1/4 MILE OR LESS. LOCATIONS THAT HAVE TEMPERATURES BELOW FREEZING MAY HAVE SLICK SPOTS ON ROADS...ESPECIALLY ON BRIDGES AND OVERPASSES.

JO DAVIESS-STEPHENSON-CARROLL-WHITESIDE-INCLUDING THE CITIES OF...GALENA...FREEPORT...MOUNT CARROLL...
STERLING...ROCK FALLS 606 PM CST THU FEB 2 2012

...DENSE FOG ADVISORY IN EFFECT UNTIL NOON CST FRIDAY...

THE NATIONAL WEATHER SERVICE IN QUAD CITIES HAS ISSUED A DENSE
FOG ADVISORY...WHICH IS IN EFFECT UNTIL NOON CST FRIDAY.

* TIMING...THROUGH THE EVENING AND OVERNIGHT HOURS AND THROUGH
MUCH OF FRIDAY MORNING.

* VISIBILITY...WIDESPREAD 1/4 MILE OR LESS.

* IMPACTS...THE DENSE FOG COMBINED WITH TEMPERATURES BELOW THE
FREEZING MARK MAY RESULT IN SOME SLICK SPOTS ON ROADWAYS...
ESPECIALLY BRIDGES AND OVERPASSES.

PRECAUTIONARY/PREPAREDNESS ACTIONS...

A DENSE FOG ADVISORY MEANS VISIBILITIES WILL FREQUENTLY BE
REDUCED TO LESS THAN ONE QUARTER MILE. IF DRIVING...SLOW DOWN...
USE YOUR HEADLIGHTS...AND LEAVE PLENTY OF DISTANCE AHEAD OF YOU.

February 2011 Blizzard: One Year Later

It's one year later but still fresh in everyone's mind.  The third largest snowfall in Rockford's history hit on the eve of January 31st and lasted through February 2nd.  Hard to believe one year has passed and how things have been so different this year than they were last winter. 

The snow that fell came in two parts; an upper level disturbance out ahead of the main low January 31st and then the main storm itself.  The upper level disturbance didn't produce much snow...only 0.8" fell.  What was most memorable for everyone was the 10.9" that fell on the first of February followed by the 3.4" that fell on the second.  The first signs of this possible winter storm started to develop in our computer weather models about a week before it actually hit.  With each run that came out, morning and evening, most models were holding on to the idea that there would be a winter storm and it would likely hit somewhere in the Midwest and Great Lakes.  It was just a matter of where the exact track would go that we wouldn't know until a few days before.  The storm brought extremely strong winds, heavy snowfall: rates of 2" to 3" per hour for some time, and crippling conditions across northern Illinois.

 A Blizzard Watch had been issued a few days in advance of this storm because the National Weather Service felt very confident that this system would have major impacts on the region.  When the storm moved closer Blizzard Warnings were issued on the first of February.

Early on February 1st the main low started to move out of the south Plains.  As it did, there were a few lake effect snow showers that had set up across northeastern Illinois.  Those lake effect snow showers even extended as far west as Rockford, which was quite impressive.  It wasn't until mid-afternoon that we started to feel the full effect of this system; winds started to increase and the snow grew heavier.  Around 2pm & 3pm drifting snow was already becoming a problem in open locations and visibility was going down.  I can still remember thinking as I was traveling to a hotel where I would try to catch a little sleep: "This is going to be a bad one".

Further south across Missouri and central Illinois blizzard like conditions continued to pour into the National Weather Service offices as the snow fell.  Winds were increasing and would soon gust as high as 50-55mph across northern Illinois later that evening.  A large area of moderate to heavy snow was falling just north of the strengthening low pressure system as it moved through southern Illinois.  What made this system so dynamic and intense was the fact it had a lot of upper level support with it.  The upper level trough began to move in and actually took on a negative tilt.  A negatively tilted upper level trough means the system, as a whole, is strengthen.  The surface low is being enhanced by the low pressure system several thousand feet above.  As long as the air continues to rise in the storm the storm will continue to strengthen.  A positively tilted trough isn't as strong.  At the same time this was occurring there were intense pressure falls out ahead of the surface low; another indication the storm would continue to intensify.  Smaller scale features, known as mesoscale features, also aided in the intense snow that set up across northern Illinois.

Later that evening on the 1st and into the wee hours of the 2nd is when the most intense snow fell.  Snow plows were called off due to safety concerns...highways were closed due to the intense nature of the blowing and drifting.  Visibility was at zero and we were experiencing true blizzard conditions.  During the overnight, the low continued to move east but as it did moisture continued to get wrapped into the storm producing lake effect snow across northeast Illinois.

Some other features that made this storm so impressive were the lightning strikes that were observed along with the thundersnow.  I'm sure many have seen The Weather Channel's Jim Cantore and his reaction to the thunder that occurred while he was live in Chicago.  To get thunderstorms in the spring and summer you need three components: lifting/forcing, moisture and instability.  You can also get these components in winter weather too.  It's just not as frequent and when it does occur you know you're dealing with an impressive storm.  With such strong features in the upper levels of the atmosphere the forcing, or lift, was not lacking.  This storm was also able to keep it's moisture supply due to the warm, moist conveyor belt pulling in moisture from the gulf.  Instability was also in full supply across northern Illinois.  The wind was also a major factor with this storm.  Strong winds not only at the surface but aloft aided in the blinding blizzard conditions.  Peak wind gusts at the Chicago/Rockford International Airport reached 48 mph.  In Rochelle winds peaked at 49 mph, DeKalb 52 mph and at the Chicago Lakefront a peak wind gust of 70 mph was recorded!

All in all, a total of 15.1" fell at the Rockford airport making this snowstorm the third largest in Rockford's history.  Significant blowing and drifting occurred with visibility near zero through the most intense part of the storm.

Here is a break down of how much snow fell  in six hour periods from the 31st through the 2nd from the Chicago National Weather Service.

Rockford, IL
Date
Time
Snowfall Amount (inches)


1/31
12PM-6PM
0.3

6PM-12AM
0.5


2/1
12AM-6AM
0.1


6AM-12PM
0.2


12PM-6PM
1.9


6PM-12AM
8.7

2/2
12AM-6AM
3.0

6AM-12PM
0.4


Rockford Statistics
January 31st-February 2nd Three-Day Storm Total Snowfall: 15.1" (Third Highest on Record)
Snowfall Total from the Afternoon of February 1st through the Morning of February 2nd: 14.0"
Calendar Day Total for February 1st: 10.9"

Dense fog and slick spots this morning

12:50pm Update: This is the sounding from the NWS in Davenport, IA and it shows a pretty strong inversion just above the surface with light winds through about 900 mb.  An inversion is when the air at the surface is cooler than the air above.  The layer is also fairly saturated so it's no wonder the fog has stuck around for so long.  With limited atmospheric mixing the fog isn't able dissapate easily.  Temperatures as a result will remain in the upper 30s to near 40° today. 

(9:02:06 AM) nwsbot: LOT extends Dense Fog Advisory for Boone, De Kalb, DuPage, Ford, Grundy, Iroquois, Kane, Kankakee, Kendall, La Salle, Lee, Livingston, McHenry, Ogle, Will, Winnebago [IL] till 3:00 PM CST

A Dense Fog Advisory continues through 10am for southern Wisconsin and northern Illinois.  Calm winds and clear skies late last night allowed the thick, dense fog to develop and expand eastward.  Visibility in almost all locations through Wisconsin and Illinois have dropped to less than a quarter mile.  Another concern this morning have been the temperatures.  A few slick spots have been reported from some of our weather watchers due to the fact temperatures have fallen below freezing.  Be sure to give yourself plenty of time this morning and watch for those slick spots; especially on bridges, overpasses, sidewalks and parking lots.  Those are most likely to become slippery. 

Despite high pressure overhead the atmosphere is fairly 'calm'.  This leads me to believe the fog is going to have a hard time lifting as we go through the morning so it's possible we could still be dealing with the fog through noon.  This will play an impact on our temperatures today, especially if the fog holds.  I did lower highs this morning to 41° rather than the 45° I had yesterday.  Should the fog lift sooner, we will have a better shot of reaching the warmer temperatures, but if it holds then we'll remain cooler.

Dense Fog Advisory

10:30pm Update: NWS Chicago has now issued a Dense Fog Advisory for the remainder of the Stateline area until 9am tomorrow. Here it is:
WINNEBAGO-BOONE-OGLE-LEE-DE KALB
INCLUDING THE CITIES OF...ROCKFORD...BELVIDERE...OREGON...DIXON...
DEKALB.

1014 PM CST WED FEB 1 2012

...DENSE FOG ADVISORY IN EFFECT UNTIL 9 AM CST THURSDAY...

THE NATIONAL WEATHER SERVICE IN CHICAGO HAS ISSUED A DENSE FOG
ADVISORY...WHICH IS IN EFFECT UNTIL 9 AM CST THURSDAY.

* TIMING...PATCHY DENSE FOG HAS DEVELOPED THIS EVENING AND WILL
CONTINUE TO INCREASE TO AREAS OF DENSE FOG THROUGH THE OVERNIGHT
PERIOD. EXPECT DENSE FOG TO PERSIST THROUGH MID MORNING BEFORE
CONDITIONS BEGIN TO IMPROVE.

* VISIBILITY...DENSE FOG WILL REDUCE VISIBILITIES TO UNDER A
QUARTER MILE AT TIMES.

* IMPACTS...TEMPERATURES WILL STEADILY COOL TO AROUND FREEZING OR
A FEW DEGREES BELOW FREEZING ACROSS THE ADVISED AREA...ALLOWING
FOG TO FREEZE ON CONTACT WITH THE GROUND. AS A RESULT...AREA
ROADS MAY BECOME SLICK. LOW VISIBILITIES WITHIN THE FOG WILL
ALSO MAKE TRAVEL HAZARDOUS. MOTORISTS ARE URGED TO TAKE EXTRA
TIME TO REACH THEIR DESTINATIONS THIS MORNING...AND TO USE EXTRA
CAUTION AT UNCONTROLLED INTERSECTIONS AND AT RAIL ROAD CROSSINGS.

PRECAUTIONARY/PREPAREDNESS ACTIONS...

A DENSE FOG ADVISORY MEANS VISIBILITIES WILL FREQUENTLY BE
REDUCED TO LESS THAN ONE QUARTER MILE. IF DRIVING...SLOW DOWN...
USE YOUR HEADLIGHTS...AND LEAVE PLENTY OF DISTANCE AHEAD OF YOU.

The National Weather Service office out of the Quad Cities has issued a Dense Fog Advisory for Stephenson, Jo Daviess, Carroll, and Whiteside counties until 10am. So far an advisory from the Chicago NWS office has not been issued for our central and western counties, but fog could still be dense in some of these areas too. Here's the full advisory from the Quad Cities office:

NATIONAL WEATHER SERVICE QUAD CITIES IA IL
933 PM CST WED FEB 1 2012

...WIDESPREAD DENSE FOG...

MOSTLY CLEAR SKIES...CALM WINDS AND FALLING TEMPERATURES HAS
DEVELOPED WIDESPREAD DENSE FOG ACROSS MUCH OF EASTERN IOWA AND NORTHWEST ILLINOIS...ESPECIALLY NEAR AND NORTH OF INTERSTATE 80. VISIBILITIES IN MANY AREAS WERE NEAR ZERO TO 1/4 MILE. THE DENSE
FOG IS EXPECTED TO CONTINUE THROUGH THE NIGHT AND INTO THURSDAY
MORNING. CONDITIONS SHOULD IMPROVE BY LATE MORNING ON THURSDAY.

JO DAVIESS-STEPHENSON-CARROLL-WHITESIDE-INCLUDING THE CITIES OF...GALENA...FREEPORT...MOUNT CARROLL...STERLING...ROCK FALLS
933 PM CST WED FEB 1 2012

...DENSE FOG ADVISORY REMAINS IN EFFECT UNTIL 10 AM CST
THURSDAY...

* TIMING...TONIGHT THROUGH MOST OF THURSDAY MORNING.

* VISIBILITY...WIDESPREAD 1/4 MILE OR LESS.

* IMPACTS...THE DENSE FOG COMBINED WITH TEMPERATURES BELOW THE
FREEZING MARK MAY RESULT IN SOME SLICK SPOTS ON ROADWAYS...
ESPECIALLY BRIDGES AND OVERPASSES.

PRECAUTIONARY/PREPAREDNESS ACTIONS...

A DENSE FOG ADVISORY MEANS VISIBILITIES WILL FREQUENTLY BE
REDUCED TO LESS THAN ONE QUARTER MILE. IF DRIVING...SLOW DOWN...
USE YOUR HEADLIGHTS...AND LEAVE PLENTY OF DISTANCE AHEAD OF YOU.

Two more billion dollar disasters added to the weather extremes of 2011

NOAA: 2011 a year of climate extremes in the United States

NOAA announces two additional severe weather events reached $1 billion damage threshold, raising 2011’s billion-dollar disaster count from 12 to 14 events

Selected Annual Climate Records for 2011 - Green dots show the wettest, yellow dots the driest, red dots the warmest and blue dots the coolest records.

According to NOAA scientists, 2011 was a record-breaking year for climate extremes, as much of the United States faced historic levels of heat, precipitation, flooding and severe weather, while La Niña events at both ends of the year impacted weather patterns at home and around the world.

NOAA’s annual analysis of U.S. and global conditions, conducted by scientists at NOAA’s National Climatic Data Center, reports that the average temperature for the contiguous U.S. was 53.8 degrees F, 1.0 degree F above the 20th century average, making it the 23rd warmest year on record. Precipitation across the nation averaged near normal, masking record-breaking extremes in both drought and precipitation.

On a global scale, La Niña events helped keep the average global temperature below recent trends. As a result, 2011 tied with 1997 for the 11th warmest year on record. It was the second coolest year of the 21st century to date, and tied with the second warmest year of the 20th century.

Key highlights of the report include:

U.S. weather and climate disasters
NOAA has identified two additional events in 2011 that caused an economic impact of $1 billion or greater, bringing the total number of major billion-dollar weather and climate disasters to 14 (not including the pre-Halloween snowstorm in the Northeast, which is still being analyzed).

From extreme drought, heat waves and floods to unprecedented tornado outbreaks, hurricanes, wildfires and winter storms, a record 14 weather and climate disasters in 2011 each caused $1 billion or more in damages — and most regrettably, loss of human lives and property.







Tropical Storm Lee, which made landfall on the Gulf Coast on September 2, caused wind and flood damage across the Southeast, but considerably more damage to housing, business and infrastructure from record flooding across the Northeast states, especially Pennsylvania and New York. The storm occurred in an area that had experienced high rainfall from Hurricane Irene barely a week earlier.

A Rockies and Midwest severe weather outbreak, which occurred July 10-14, included tornadoes, hail and high winds. Much of the damage was from wind, hail, and flooding impacts to homes, business, and agriculture.

Together, these two events resulted in the loss of 23 lives (21 from Tropical Storm Lee, 2 from the Rockies/Midwest outbreak).

Nationally
Warmer-than-normal temperatures were anchored across the South, Mid-Atlantic and the Northeast. Delaware had its warmest year on record, while Texas had its second warmest year on record. The U.S. has observed a long-term temperature increase of about 0.12 degrees F per decade since 1895.

Summer (June-August) 2011 was the second warmest on record for the Lower 48, with an average temperature of 74.5 degrees F, just 0.1 degree F below the record-warm summer of 1936. The epicenter of the heat was the Southern Plains, where Louisiana, New Mexico, Oklahoma and Texas all had their warmest summer on record. The 3-month average temperatures for both Oklahoma (86.9 degrees F) and Texas (86.7 degrees F) surpassed the previous record for warmest summer in any state.

With the exception of Vermont, each state in the contiguous U.S. had at least one location that exceeded 100 degrees F. Summertime temperatures have increased across the U.S. at an average rate of 0.11 degrees F per decade. Much of this trend is due to increases in minimum temperatures (“overnight lows”), with minimum temperature extremes becoming increasingly commonplace in recent decades.

Despite a “near normal” national precipitation average, regional precipitation outcomes varied wildly. Texas, ravaged by exceptional drought for most of 2011, had its driest year on record. In contrast, seven states in the Ohio Valley and Northeast — Connecticut, Indiana, Kentucky, New Jersey, New York, Ohio, and Pennsylvania — had their wettest year on record.

The past nine years have been particularly wet across the Northeast region - since 2003, the annual precipitation for the region is 48.96 inches, 7.88 inches above the 20th century average. Precipitation averaged across the U.S. is increasing at a rate of about 0.18 inches per decade.

Precipitation extremes and impacts were most prevalent during spring (March - May) 2011. Across the northern U.S., ten states were record wet, and an additional 11 states had spring precipitation totals ranking among their top ten wettest. These precipitation extremes, combined with meltwater from a near-record snow pack, contributed to historic flooding along several major rivers across the central United States.

Meanwhile, drought rapidly intensified in the southern Plains, where Texas had only 2.66 inches of precipitation, its driest spring on record. This led to record breaking drought and wildfires, which devastated the southern Plains. Following 2010, during which drought across the country was nearly erased, the 12 percent of the continental U.S. in the most severe category of drought (D4) during July 2011 was the highest in the U.S. Drought Monitor era (1999-2011).

The spring brought a record breaking tornado season to the United States. Over 1,150 tornadoes were confirmed during the March-May period. The 551 tornado-related fatalities during the year were the most in the 62-year period of record. The deadliest tornado outbreak on record (April 25-28th) and the deadliest single tornado (Joplin, Missouri) contributed to the high fatality count.

Globally
This year tied 1997 as the 11th warmest year since records began in 1880. The annual global combined land and ocean surface temperature was 0.92 degrees F above the 20th century average of 57.0 degrees F. This marks the 35th consecutive year, since 1976, that the yearly global temperature was above average. The warmest years on record were 2010 and 2005, which were 1.15 degrees F above average.

Separately, the 2011 global average land surface temperature was 1.49 degrees F above the 20th century average of 47.3 degrees F and ranked as the eighth warmest on record. The 2011 global average ocean temperature was 0.72 degrees F above the 20th century average of 60.9 degrees F and ranked as the 11th warmest on record.

Including 2011, all eleven years of the 21st century so far (2001-2011) rank among the 13 warmest in the 132-year period of record. Only one year during the 20th century, 1998, was warmer than 2011.

La Niña, which is defined by cooler-than-normal waters in the eastern and central equatorial Pacific Ocean that affects weather patterns around the globe, was present during much of 2011. A relatively strong phase of La Niña opened the year, dissipated in the spring before re-emerging in October and lasted through the end of the year. When compared to previous La Niña years, the 2011 global surface temperature was the warmest observed.

The 2011 globally-averaged precipitation over land was the second wettest year on record, behind 2010. Precipitation varied greatly across the globe. La Niña contributed to severe drought in the Horn of Africa and to Australia’s third wettest year in its 112-year period of record.

Arctic sea ice extent was below average for all of 2011, and has been since June 2000, a span of 127 consecutive months. Both the maximum ice extent (5.65 million square miles on March 7th) and the minimum extent (1.67 million square miles on September 9th) were the second smallest of the satellite era.

For the second year running, NCDC asked a panel of climate scientists to determine and rank the year’s ten most significant climate events, for both the United States and for the planet, to include record drought in East Africa and record flooding in Thailand and Australia. The results are at http://www.ncdc.noaa.gov/climate-monitoring.

Scientists, researchers and leaders in government and industry use NOAA’s monthly and annual reports to help track trends and other changes in the world's climate. This climate service has a wide range of practical uses, from helping farmers know what and when to plant, to guiding resource managers’ critical decisions about water, energy and other vital assets.


NOAA’s mission is to understand and predict changes in the Earth's environment, from the depths of the ocean to the surface of the sun, and to conserve and manage our coastal and marine resources. Join us on Facebook, Twitter and our other social media channels.





A look back at January

January 2012 will go down in the record books as a mild month.  As far as temperatures, January ended almost 6° above the monthly average and really wasn't too far behind in terms of precipitation.

There were six 50° days during the month, two in the beginning, two in the middle and two to round out the end of the month.  A few record highs were also tied.  So, is this any indication as to what the remainder of winter will be like?  Weather tends to continue what it has been doing in the past.  While we've had a few cold spells here and there, it has always warmed quickly after.  Going into February we're starting above average; temperatures will be in the upper 30s/low 40s today, the low 40s tomorrow and Friday.  There will be a cool down next week following the passage of an area of low pressure, but it's not expected to be a major one as the chilly air will be modified as it travels south.

The latest outlook from the Climate Prediction Center for the month of February has above average temperatures for much of the U.S and above average precipitation near the Great Lakes.