Thursday, September 19, 2019

Dry Stretch Comes to an End

High pressure has kept the Stateline dry for most of the week. Whether you like it or not, the dry stretch of weather that we have become accommodated to over the past few days has come to an end. This morning started off with a line of heavy rain and storms that slowly pushed into the Stateline from the northwest. A few of our viewers actually captured the shelf cloud that was on the leading edge of these storms. The photo to the left was captured by Jason Grey in Dakota, IL. Thanks to Jason and to everyone who sent in a photo this morning.

Now, there was plenty of moisture in the atmosphere as this line materialized earlier this morning which means rain fell heavy at times. Especially over Jo-Daviess and Stephenson counties. That is why these two counties and also Carroll county are under a Flash Flood Watch until 4 PM this afternoon. Because of how slow moving these storms were at the start, these areas have received 2″ to 4″ of rainfall on top of an already saturated terrain.

This area of heavy rain continues to inch toward the southeast. No severe weather is expected, but these storms have had a history of producing very heavy rainfall. Models tend to weaken this activity as it moves through northern and central Illinois, curbing the flash flood potential locally. After taking that into consideration, rain totals will likely remain well under one-inch for most. The exception to that will be areas that got under the slower moving thunderstorms earlier. The rain looks to taper off by 3 p.m. and drier weather should take over for the rest of the day. All of the clouds and rain shower activity this morning into early afternoon will keep our highs in the same ballpark as the past few days. Winds will be out of the south through the day so the humid conditions will continue.

If you have outdoor plans this evening, most of us will see drier conditions until the overnight hours.An isolated evening shower cannot be ruled out. Cloudy to mostly cloudy skies will linger through the night, keeping overnight lows held into the middle 60’s. Scattered thunderstorms redevelop during the hours of before sunset. This means a wet morning commute is possible as we head into the end of our work week. It would definitely be a good idea to have the umbrella ready before you head out there door tomorrow morning. Condition seems to dry out by tomorrow afternoon to partly sunny skies. The humidity will also stick with us as we head into our Friday and also the weekend. 

Wednesday, September 18, 2019

Heavy Rainfall Threatens the Weekend

Heavy rainfall and severe weather have impacted parts of Texas and Louisiana as Tropical Depression Imelda moves onshore. As the remnant low pressure system becomes caught in the flow of the jet stream, it will pull quite a bit of Gulf moisture northward into the lower Great Lakes.

Isolated showers and thunderstorms will be possible both Thursday and Friday, but heavy
rainfall will be possible Saturday and Sunday across Iowa, Illinois and Indiana. It's yet to be seen where exactly the heavy rain will set up, but where it does rainfall totals could add up to another couple inches. This next system comes after over 7 inches of rain have fallen over northern Illinois and southern Wisconsin just within the past week and a half. The long range outlook through the end of the month features temperatures remaining above average, but also the possibility for above average precipitation.

So far, the month of September is the 4th wettest September on record (this is through the 18th). The wettest September on record was September 1961 when 10.68 inches fell. 

Rain Chances on the Rise Thursday Morning

We've had some pretty nice weather these past few days, and while the warm weather will continue the chance for rain and thunderstorms will be on the increase. Light showers west of the Mississippi River in northeast Iowa will continue to weaken, but may hold together long enough to bring a light shower or two over northwest Illinois Wednesday evening. Otherwise, skies are expected to remain mostly to partly cloudy overnight.

Thunderstorms will develop overnight from Iowa to Minnesota, moving east into Wisconsin through sunrise Thursday. The early hours of Thursday will most likely remain dry, but thunderstorms will slowly sink south through mid to late morning. The heaviest rainfall may stay focused more to our north, but a few heavier downpours are possible through mid-morning. After that, skies will turn partly sunny with an isolated shower/storm chance through the afternoon.

Widespread heavy rainfall is not expected, but there could be some rainfall totals nearly half an inch to three quarters of an inch by Thursday afternoon. The highest rainfall totals will likely occur to our northwest, stretching from southwest Wisconsin into northeast Iowa.

The Tropics Are Heating Up

Hurricane Season takes up six months of the year and spans from June 1st through November 30th. We just passed the statistical peak of the season which is around September 10th. Things have began to pick up across the Atlantic and Pacific basins as we now head into the second half of hurricane season. As of right now, we have 6 named storms spanning across the two basins. The only tropical cyclone that is not listed on the graphic is Tropical Storm Kiko which is now on the farther west side of the eastern Pacific Ocean.
First, we have Hurricane Humberto. The latest update continues to show this system tracking to the north of Bermuda and eventually moving out to sea. Hurricane hunters have found that this storm has strengthened into a major hurricane (category 3+ on the Saffir-Simpson Scale), with winds up to 120 mph. This is the second major hurricane of the 2019 season, the first being Hurricane Dorian. Humberto could bring some huge impacts such as dangerous winds, heavy rainfall, and storm surge to the island of Bermuda tonight into Thursday. As of a result, the National Hurricane Center has posted a hurricane warning for the island.

A quick developer, Imelda started out as an upper-level low over the southeast U.S that gained tropical-like characteristics as it churned over the Gulf of Mexico. 15 minutes before this system made landfall in southeast Texas, they gave it the name Imelda. Now, the National Hurricane Center has stopped issuing advisories for Imelda due to the fact that it has become post-tropical. Hurricanes are warm core storms.
When a tropical cyclone becomes post or extra-tropical, it loses its warm core and then turns into a cold core storm. However, 10-15 inches of rainfall have fell over portions of the southeast coast of Texas, including the city of Houston. In the last advisory, it states that rainfall totals could range from 20-25 inches when it is all said and done.

Now the one to watch is now the tenth named storm of the Atlantic hurricane season, Tropical Storm Jerry. This storm is already showing signs of intensification as it churns across the Atlantic Ocean. You have strong thunderstorm activity around the center of circulation, and you have traverse banding overhead. Traverse banding is an indication that the tropical cyclone is well ventilated. Meaning that Jerry is breathing well and is healthy at the moment. Maximum sustained winds have increased to near 50 mph with higher gusts. Jerry is forecast to become a hurricane by late Thursday, with little change in strength anticipated on Friday and Saturday.

Tuesday, September 17, 2019

Another Foggy Start, Sunshine to Follow

Aside from the patchy fog, today will see a repeat of the tranquil weather we experienced yesterday. If you’re preparing to walk out the door, don’t forget the sunglasses today. Despite the cloudy and foggy start, sunny skies will return later in the day. Today will feature a bit more cloud cover than what the Stateline experienced on Monday, but the dry stretch will continue. Most spots today will climb into the low 80s. Some areas of patchy fog could linger through the late morning hours before fully tapering off by this afternoon. Moisture will continue to stream in from the southeast today and tomorrow, before winds turn to the southwest as we head into the second half of the work week. This will help keep the humid weather around for a little while longer, meaning more foggy morning’s are possible this week.

Models continue to hint that we could experience some patchy fog during the morning commute tomorrow. Any fog that forms will quickly burn off to partly sunny skies which will allow our highs to climb into the low 80s once again. As high pressure continues to slide east, increasing moisture will get pulled into the Stateline. Thursday morning will bring the next chance for rain as our next system approaches. Rain chances will remain early on in the day, especially around the time when you are heading out the door. So having the rain gear on hand Thursday morning wouldn't be a bad idea. Rain should begin to taper off by the early afternoon.

Along with Thursday's early rain chances, the overall threat for severe weather is low. But  heavy rain will be possible with any showers that do move through. Thursday will be the first of several unsettled days. Over the next five to seven days, widespread rainfall totals could be between .5″ to as much as 1.5″. Due to the large amount of rainfall we received last week, flood warnings remain in effect for the Pecatonica and flood advisories remain in place along portions of the Rock River. Despite having a good stretch of dry weather, this newly added rainfall could cause river levels to rise leading to more flooding issues across the Stateline.

The unsettled weather pattern will continue into the weekend. A few things remain uncertain as we still have much of the week left. Models generally agree that Saturday features the best chance for rain with a passing cold front. This cold front giving us showers and storms this weekend will sweep through, bringing a return to more fall-like temperatures just in time for the official start of fall next Monday. As of a reminder, the Autumn Equinox occurs on Monday, September 23rd at 2:50 A.M central time. Typically, our average highs are in the low 70s and our average lows end up in the upper 40s.

Monday, September 16, 2019

Areas of Fog Possible Again Tuesday Morning

Locally dense fog may once again develop early Tuesday morning, however, increasing cloud cover from the west could limit just how dense the fog gets. Clouds have slowly begun to increase from the west as a fairly strong upper level low moves through the central Plains.

Wind speeds will also be a little higher than what they were Sunday night which may help to mix the atmosphere through the morning. Where clouds aren't too thick, however, dense fog could rapidly develop given how much moisture is present in the atmosphere. Early commuters Tuesday morning should allow a little more extra time for their drive, and make sure to pay close attention around bus stops in the morning.

Foggy Start Leads to Afternoon Sunshine

Dense fog this morning slowed things down a bit as we started off our work week. Most spots as you woke up were already registering visibility under a 1/2 mile. Now that the sun is up and has began to heat the surface, the fog layer is dissipating which has resulted in improving conditions across the Stateline. A dense fog advisory remains in effect for the entire viewing area until 10 A.M.

When you are driving in a layer of dense fog, it is important to keep these safety tips in mind. Remember to always with your low beams. If you are driving through dense fog with your high beams on, the bright light from your high beams will reflect off the ice crystals of the fog reducing your visibility even more. Also, make sure to give yourself enough space between you and the car in front of you. Just in case of any unexpected stops. This will lessen the chances of you or other drivers getting into an accident.

Dense fog should burn off by around 10-11 AM, but patchy areas of fog may remain through the late-morning. Besides the foggy start, conditions look to stay dry for the first half of the work week. As more dry air is filtered into the region, partly sunny skies will dominate most of our day. Highs will climb into the low 80s. As the official start of fall approaches, summer-like warms seems to settle in for the entire work week. Highs temperatures will remain anywhere from 5° to 10° above average. You can thank a large dome of high pressure over the deep South.There may be a slight cool down as we head into our weekend as a cold front passes through. However, temperatures are likely to remain above-average between now and late in the month.