Coating to 1"+ of snow possible by Friday noon along the I-94 corridor including the metro
1" to 3"+ snowfall for western & south central Minnesota through Friday morning (Generally either side of a Wheaton-Redwood Falls-Mankato-Rochester line)
December 3rd last 1" snowfall at MSP Airport (4.2")
Potentially slick roads early Friday!
40s in metro New Year's Eve between 2pm and 6pm
30s with a chance of snow by midnight to ring in 2012!
Pattern changes ahead:
Don't look now, but it looks like Old Man Winter may finally wake up from a deep sleep.
The first meaningful snow since December 3rd arrives into early Friday. It looks like a coating to an inch in most areas, but it should be enough to get your attention Friday morning!
The models have been all over the place with this system. First they leaned toward light totals, then the NAM churned out suggested snowfall of over 4" for the metro. Now the NAM is printing out a big fat zero for the metro, a change that did not go unnoticed in Friday afternoon's forecast discussion from the Twin Cities NWS.
AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE TWIN CITIES/CHANHASSEN MN
320 PM CST THU DEC 29 2011
WAS FAIRLY CONFIDENT EARLIER TODAY LOOKING AT 12Z MODEL RUNS THAT
WE WOULD SEE A STRIPE OF 2-4 INCHES OF SNOW ACROSS WC MN TO MSP
OVERNIGHT. NOW THE 18Z NAM AND THE 12Z ECMWF ARE TAKING THE TRACK OF
THE SURFACE LOW FARTHER SOUTH...INTO SE IA BY 12Z AS 700 MB LOW
TAKES A MORE SLY TRACK. MORE SOUTHERLY TRACK WOULD AT LEAST SHINK
THE AREA WHICH WOULD BE AFFECTED BY RAIN AS SYSTEM LOOKS LIKE IT
WILL BE A BIT COLDER. MUCH OF THIS CHANGE SEEMS TO BE DUE TO MODELS
NOW TYING MORE INTO THE VORT MOVING ACROSS WY INTO W NEB RATHER THAN THE VORT DROPPING OUT OF SASK INTO NW MT. AN EXAMPLE OF THE HUGE CHANGE IN MODEL OUTPUT IS THE .42 QPF THAT THE 12Z NAM FOUS67 DUMPED ON MSP TO THE BIG ZERO PRODUCED FROM 18Z OUTPUT. PRETTY FRUSTATING WITH SUCH SWINGS IN GUIDANCE. CUT BACK ON THE QPF/SNOW AMOUNTS THAT ORIGINALLY CONTEMPLATED...AND PUT SOME SNOW AMOUNTS INTO THE SC AREAS WHERE COLUMN LOOKS LIKE IT WILL NOW COOL SUFFICIENTLY FROM UPPER LOW TRACKING ACROSS IA. ENDED UP WITH A BROADER BAND OF 1-3 INCHES SNOW.
The rapid model changes have lead to changing graphical forecasts today.
Here's the NWS update frm Thursday morning.
Here's the midday Thursday update...
And Thursday night...
Model trends do the system sliding further south with each passing run. The 18Z NAM has it missing the metro to the south. The GFS likes 1.3" of snow at MSP Airport.
(Click image below to enlarge snowfal output.)
My sense is that the northern end of snow band should be centered along the I-94 corridor from Alex to St. Cloud into the Twin Cities and over to Eau Claire. Latest model trends favor heavier snow in south central Minnesota along the Minnesota River, generally either side of a Wheaton-Redwood Falls-Mankato-Rochester line
Temps should be just cold enough in the lowest mile of the atmosphere for mostly snow tonight into early Friday. Roads may be a bit slick in spots for Friday AM rush hour. Remember snow... and rush hour?
It won't be a big deal by Minnesota standards but it should get your attention!
Let's see if tonight's 0Z model run sheds any new light on this fickle system.
Changeable New Year's!
New Year's Eve and Day will be a bit of a roller coaster ride this year.
Mild air will be drawn up ahead of approaching and deepening low pressure Saturday. Temps should crack the 40s New Year's Eve afternoon, then fall into the 30s between 6pm and midnight.
As the low pulls by, winds will shift into the west and northwest, and rain may bust out...changing to all snow on New Year's Eve. It may be snowing in the metro and much of eastern Minnesota by the time you ring in 2012!
The overnight models runs have backed off snowfall potential a bit (1" to 2" range?) but we'll have to watch this system closely.
Colder air will gush in on gusty northwest winds for New Year's Day. It may be a blustery, cold and white New Year's Day to open 2012!
Feels more like January?
The first few days of January should feel like it with highs in the teens north and 20s south and lows in the single digits and teens.
According to the GFS model, one more gush of milder Pacific air comes spilling over the Rockies about January 5th...with another shot at 40 degrees.
After that the overall weather pattern begins to look more like winter. Models are pushing colder, potentially arctic air into Minnesota around January 12-13th.
There may also be increasing chances for meaningful snow that could produce lasting snow cover as we move into mid-January.
Alaskan Chill Factor:
Temps are running between -30 to -45 in Alaska's interior today.
It's finally getting cold in Alaska, and chunks of that bitter air may break off and head south in the next 2 weeks.
The bottom line is our extended premature January thaw may be about to end. It may happen in stages...but it looks like winter is finally on the way!
Question for you Paul: Is the ground frozen, or still somewhat permeable to moisture? Thanks
Another question -- so far as I can tell, we've not had a below zero reading yet this season here in MSP. What's the latest date in a Twin Cities meteorological winter that we've had a first low below zero?
The latest the Twin Cities went without a subzero reading was in the winter of 2001-2002 when it took until January 18th to get that cold.
Here's the relevant information from the State Climatology Office: