Satellite images can tell us a lot

Current cloud trends upstream are beginning to show a little growth in the cloud layer in response to an upper level disturbance moving through the Midwest.  While it's hard to find much precipitation reaching the ground this morning, there have been a lot of radar returns popping up.  The atmosphere is still fairly dry, but going through this morning I wouldn't be suprised if a few flakes/sprinkles were able to make it to the ground.  Some of this cloud cover may thin out but a clipper system will move through later in the day keeping the slight chance of showers in the forecast.

This (Mild) Winter To-Date

Valentine's Day has come and gone, and I noticed buds on the trees in my neighborhood this morning with sunshine and balmy temperatures. Skies quickly clouded-over during the afternoon, but we still managed to reach 40 degrees or higher for the 32nd time in Rockford this Meteorological Winter.

If you have a heart for 40-degree weather and a lack of snow, this has certainly been your year! (I don't, but that's besides the point...) We've been 40 degrees or better on 42% of our days this winter, and have only had 2 days with 6" or more of snow cover. Here's more from the NWS office in Chicago, including how this winter compares to last.

I'm hoping my cross country skis see more action next winter.  --TS

Temperatures are the key to what we'll see

Temperatures at the surface and aloft are all key as to what type of precipitation we'll receive later today and tonight.  The initial push of warm air this morning was experienced in the form of cloud cover and fog.  While we've still got the fog (dew points continue to rise) the clouds are beginning to depart and this will mean we've got a better shot of highs this afternoon reaching the lower 40s. 

The cloud cover will begin to move back in tonight ahead of a surface low currently lifting east/northeast out of the Texas/Oklahoma panhandles.  This low will move into Missouri by late this afternoon and then into southern Illinois overnight.  Southerly winds out ahead of the low will continue to bring a warm air mass in not only at the surface, but several thousand feet above.  Light rain may begin to spread northward by this afternoon, but the chance for rain will increase this evening and overnight.  Temperatures are likely to remain mild enough to support rain through the majority of this event; totals could possibly near 0.25".  A cold front will move in from the northwest with the northern branch of the jet stream, however, there really isn't that big of a punch of colder air behind it.  So, without that cold air in place it may be difficult to get a complete change over to snow.  It's likely we'll have a rain/snow mix overnight with some wet snow flakes flying Thursday morning.  Another aspect to consider will be our dew points.  These numbers will be rising into the low 30s and typically when you have dew point readings near 30° or higher it's hard to get a complete change over to snow.  Of course, as this system evolves today we'll continue to provide updates here as needed.  But, I think the fact that we've got sunshine this morning and the possibility of reaching the low 40s this afternoon will be in our favor once the precip does start to fall.

Light snow falling now: Watch for slick spots

An upper level trough in eastern Iowa helped redevelop light snow early this morning.  This snow is now passing through north-central Illinois and south-central Wisconsin.  What I've noticed the past hour or so is the snow is expanding a bit in coverage and there has been a little enhancement with a few embedded snow bands.  While it's likely not going to amount to much it may be enough to cover the ground and slicken up your morning commute.  There was a little freezing drizzle overnight that had caused secondary roads, bridges/overpasses, sidewalks and parking lots to become slick, but the threat for this morning will remain the snow.

Visibility has dropped where the snow is falling so make sure you use your headlights while traveling.  The clouds will probably last through the better part of the afternoon.

Freezing Drizzle Tonight

The NWS office in Chicago has issued a special weather statement for the potential for freezing drizzle overnight. Although this freezing drizzle will not amount to more than 0.1", this will still be enough for tricky travel... Especially on untreated roads. Here is the NWS statement:


WINNEBAGO-BOONE-MCHENRY--OGLE-LEE-DE KALB-
INCLUDING THE CITIES OF...ROCKFORD...BELVIDERE...WOODSTOCK...
...OREGON...DIXON...DEKALB...
SNOW TO END TONIGHT WITH PATCHY FREEZING DRIZZLE POSSIBLE...

LIGHT SNOW WILL CONTINUE THROUGH THE MIDNIGHT TIME FRAME TONIGHT
BEFORE SLOWLY SHIFTING EAST OUT OF THE AREA. WITH THE DEPARTURE OF
THIS SNOW...A PERIOD OF PATCHY LIGHT FREEZING DRIZZLE WILL BE
POSSIBLE ACROSS PORTIONS OF NORTHEAST ILLINOIS AND NORTHWEST INDIANA. ALTHOUGH THE EXTENT OF THIS FREEZING DRIZZLE AND THE
EXACT TIMING OF THIS TRANSITION REMAIN UNCERTAIN AT THIS
TIME...THE CHANCES FOR THIS LIGHT FREEZING DRIZZLE WILL BECOME
MORE LIKELY FOR AREAS ALONG AND WEST OF A ROCKFORD TO WATSEKA LINE
EARLY TUESDAY MORNING. WITH TEMPERATURES IN THE UPPER 20S...SOME
SLIPPERY SPOTS MAY FORM ON AREA ROADS AND POSSIBLY LINGER INTO THE
MORNING COMMUTE.

ANYONE PLANNING TRAVEL OVERNIGHT SHOULD BE AWARE OF SLIPPERY ROAD
CONDITIONS. BE ESPECIALLY CAUTIOUS ON ELEVATED ROAD SURFACES SUCH
AS BRIDGES AND OVERPASSES WHICH TYPICALLY SEE ICE FORMATION BEFORE
OTHER AREAS.

Snow chances this week

Two systems will impact our weather this week; the first has been bringing widespread snow across Iowa and Missouri early this morning.  This snow will continue to spread into Wisconsin and Illinois with accumulations nearing two inches or so.

The second is currently punching into northern Canada and will be with us late Wednesday night and Thursday. 



Probability of snow > 4" Wednesday



The track of the second one will be one to pay close attention to in the following days.  As this low moves into the southwest a surface low pressure system will develop along the Oklahoma/Texas panhandles and lift northeast Wednesday to near Chicago by Thursday morning.  As we may remember, lows that take this track could be big snow producers.  With this type of track the heaviest snow band would set up just northwest of the surface low track placing the snow across north-central and northeast Iowa, southeast Minnesota and central Wisconsin.  Warm air lifting northward in the upper levels and surface would likely leave us with rain or a rain/snow mix Wednesday night.  Should this low track further south in the coming days then the heaviest snow band would shift further south as a result leaving us with accumulating snow; possibly over 4" or more.  Stay tuned!

Snow moves in later today

High pressure dominated the weekend with blue skies and chilly temperatures.  This morning clouds have replaced the clear skies and those clouds will continue to thicken through the morning and afternoon.  Light to moderate snow has been moving through Iowa all morning with accumulations ranging between 1" to 3". 

Looking at current surface observations the snow is now falling from Cedar Rapids up through Waterloo and this snow will continue to move northeast and likely enter our far northwest Illinois counties later this morning.  All of us will experience snow going into the afternoon and for the evening commute.

While there are no advisories for the immediate Stateline area, there are Winter Weather Advisories extending through much of the middle of the U.S.  Warm, moist air out ahead of an upper level low will continue to advance north and east.  The forecast sounding (atmospheric profile) from Davenport, IA this morning still shows a fairly dry layer of air above the surface but the precipitation that has been falling so far out west has helped to quickly saturate the air mass and allow the snow to fall and accumulate.  Totals from the snow could near 2", but if a heavier bout of snow falls some of those totals may increase a little.  The snow will last into the overnight and may mix with a little freezing drizzle as dry air once again moves into the system.  This will linger into Tuesday morning with mostly cloudy skies expected for the remainder of the day.

The commute this morning will be fine but as you head home from work or school later this afternoon and evening roadways may become a little slick with the freshly fallen snow.