Tuesday, December 18, 2012

A light dusting of snow Tonight/Wednesday; Big snowstorm well to our south Wed-Fri; Cool temps-but nothing arctic thru Christmas.

/Issued 3:45 PM CST, Tuesday, December 18th, 2012/

-The surface map below screams blizzard potential on Thursday from Central/Eastern Iowa, to Southern and Eastern Wisconsin with deep low pressure centered in Western Missouri at 6am Thursday.  The black lines are the isobars, the closer together they are, the stronger the winds.  (Source, 12z European Ensemble model)

-Big time trouble ahead for Wednesday-Friday for much of the Central Plains into the Central Great Lakes as a major winter storm dumps 6+" of snow along with very strong winds of greater than 30 mph from Kansas and Nebraska, northeast to Wisconsin and Michigan.  Blizzard warning and watch has already been issued for Eastern Colorado and Western Kansas.  I wouldn't be surprised to see the NWS upgrade to a blizzard warning farther northeast, including portions of Iowa and Wisconsin.

-Storm track for mid to late week per HPC.  Kansas/Oklahoma border Wednesday Evening to Central Illinois Thursday Morning to Lake Huron by Friday Morning.  This type of track is too far southeast of Duluth to give us any snow.

Today's Weather Summary for Northeast Minnesota and Northwest Wisconsin

Mostly cloudy to partly sunny skies were common Today with some flurries and light snow showers.  Highs were in the 20s to around 30 degrees with light and variable winds at around 10 mph.

Today's Upper Level Analysis:

Several disturbances were over the Northern U.S. Today.  The most potent one was moving into Northern Illinois late This Afternoon per water vapor satellite imagery, that system dropped a quick couple inches of snow Today in parts of Southern Minnesota.  A second disturbance is churning east through North Dakota, a 3rd disturbance was in Western Ontario.  A powerhouse jet of up to 160 knots stretched from Southern California to the Central Rockies, east to Iowa, and into the Southeast U.S. per RAP model analysis with a powerful storm digging SE into the Southwest U.S. Today with height falls of 60-150 meters.  850mb temperatures as of 3 PM ranged from -2 to -10C in Minnesota.

Forecast Discussion for Northeast Minnesota and Northwest Wisconsin

Short Term - Confidence:  High.

Tonight (December 18th)

A weak system will move east out of the North Dakota Tonight, some flurries and light snow showers will be found in Northeast Minnesota and Northwest Wisconsin Tonight due to that disturbance.  Accumulations if any will stay under 1".  Partly to mostly cloudy skies are forecast with lows in the single digits to lower 20s.  Winds will be out of the south or west at 5 to 15 mph.

Wednesday and Wednesday Night (December 19th)

A weak area of low pressure along with a cold front will affect the Northland's weather on Wednesday, may see some more flurries Tomorrow along with partly to mostly cloudy skies.  A much bigger storm will head into the Southern Plains on Wednesday before it takes the turn toward the northeast Wednesday Night.  Snow associated with that storm will stay well to our south Tomorrow Night.  Highs on Wednesday will be in the 20s and 30s with lows Wednesday Night in the teens and 20s.  Southwest winds will become west or northwest Tomorrow Night.  Wind speeds will range from 10 to around 20 mph.

Extended Forecast - Confidence:  High.

Thursday through Saturday (December 20th-22nd)

A high impact winter storm will hit Southern, Eastern, and possibly even Central Wisconsin on Thursday into Friday Morning as deep low pressure passes near or slightly east of Chicago, Illinois.  This storm will move into the Eastern Great Lakes on Friday.

Lake effect snow showers could develop Thursday and Friday in Ashland and Iron Counties in Northwest Wisconsin as N/NW winds on the backside of that low pressure system combine forces with colder air rushing over Lake Superior, this could lead to several inches of lake effect snow later this week along the South Shore of Lake Superior, mainly affecting Ashland and Iron Counties the way it looks now.

The rest of the Northland should be dry Thursday through Saturday.  High temperatures on Thursday will range from the teens in Northern Minnesota with 20s and lower 30s elsewhere.  Teens and 20s are expected for daytime highs for both Friday and Saturday.  Low temperatures will range from the single digits to around 20 Thursday Night with lows of -5 to +15 for Friday Night.

-HPC still has slight and moderate probabilities for at least 12" of snow Wednesday Night-Thursday Evening from Eastern Iowa to Eastern Upper Michigan.

-Here's the 4" or greater snowfall potential for Wednesday Night-Thursday Evening per HPC.

Long Range Forecast - Confidence:  Medium.

(December 23rd-28th)

Near normal to perhaps a bit below average temperatures are forecast through this period.  Really aren't any big signs of a major storm impacting our weather during the Christmas holiday, and days after Christmas, but we still could get some light snow or flurries at times from the 24th-27th, there's even a chance (albeit small at this point) that we get an E-NE wind coming down Lake Superior early-mid part of next week which could lead to some North Shore lake effect snow.


.Tonight...  Flurries and light snow showers at times.  Considerably cloudy skies.  Low 15 to 20.  Wind south at around 10 mph.

.Wednesday...  Partly sunny.  Flurries possible.  High 26 to 31.  Wind southwest at 10 to 15 mph.

.Wednesday Night...  Partly to mostly cloudy.  Low 15 to 20.  Wind becoming northwest at 10 to 15 mph.

.Thursday...  Partly sunny.  High 20 to 25.

.Thursday Night...  Partly cloudy.  Low 5 to 10.

.Friday...  Partly cloudy.  High 13 to 18.

.Friday Night...  Partly cloudy.  Low 0 to 5.

.Saturday...  Partly cloudy.  High 17 to 22.

Normal temperatures for Today

High:  21
Low:    6

Sunrise Wednesday:  7:50 AM CST
Sunset Wednesday:   4:22 PM CST