Area Forecast Discussion
Issued by NWS Twin Cities, MN

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FXUS63 KMPX 251145
AFDMPX

Area Forecast Discussion
National Weather Service Twin Cities/Chanhassen MN
545 AM CST Sun Feb 25 2018

.SHORT TERM...(Today and tonight)
Issued at 348 AM CST Sun Feb 25 2018

Early this morning, the snow has come to an end across the forecast
area, and all winter headlines have been lifted. The surface low was
over the UP of Michigan as of 3AM CST, and continuing quickly
northeast. For us, this means the final light bands of snow on the
back side have just departed eastward, with our concern mainly the
breezy conditions and sky cover. Low stratus on the backside of the
system continues to progress east, already bringing clearing to most
of southwestern MN.

The clearing skies from the main cloud shield associated with the
system will continue eastward this morning, but there is a secondary
area of stratus dropping southeast across North Dakota. The
guidance agrees that these clouds will erode as they mix with drier
air to the south, so kept a partly cloudy forecast.  Overall, most
of the area will see plenty of sunshine today with temperatures
warming to around freezing.  It will be a windy day through, with W
or WSW winds of 10-20 MPH and gust up to 25-30 MPH as the surface
low deepens to our northeast.  Winds will taper tonight and
temperatures will fall into the lower teens, possibly single digits
under clear skies.

.LONG TERM...(Monday through Saturday)
Issued at 348 AM CST Sun Feb 25 2018

Two main chances for precipitation next week. The first chance is
Wednesday night into Thursday. This has the potential to be a
significant winter storm across the northern part of Iowa and
southern part of Minnesota along the I-90 corridor. The second
chance for precipitation is over the weekend. There is high
uncertainty with both of these storms, and both will be warm enough
that there could be rain/snow issues.

Monday through Wednesday will be dry as upper level ridge off the
west coast breaks across a longwave trough over the Rockies. The end
result is subsidence and high pressure over the Upper Midwest, with
a shortwave trough that is cut off at H500 that is located over the
desert southwest Tuesday night. This trough will get caught up in
the strong subtropical jet and propagate eastward, while the
northern stream sends a shortwave across the high plains.

The 25.00 GFS/GEM/ECMWF are in good agreement with these two PV
anomalies through about 18Z Wednesday, but beyond that confidence in
the forecast deteriorates quickly.  The reason being eventually the
two PV anomalies will phase and a strong cyclone will develop with
over an inch of QPF in the form of snow on the cold side, and severe
weather on the warm side. The GFS is quicker, and dumps this heavy
snow across southwest Minnesota into western Wisconsin Wednesday
night into Thursday. The ECMWF and GEM are a bit slower and develop
most of the precipitation to the east of the forecast area with
slightly warmer solutions meaning more rain/snow. Given the high
variability of the ingredients that precede this cyclogenesis, did
not have the confidence to latch on to any one particular solution.
Odds are this will be a low-confidence, but potentially high-impact
forecast for the next couple of days.

Friday will be dry, but another strong upper level trough will set
up over the Pacific Northwest and send shortwave energy across the
Upper Midwest brining a chance of rain/snow. Needless to say the
active weather pattern will continue into early March.

&&

.AVIATION...(For the 12Z TAFS through 12Z Monday morning)
Issued at 541 AM CST Sun Feb 25 2018

The low pressure system continue to lift northeast through Lake
Superior this morning. The main cloud shield with ceilings around
800 to 1200 feet will continue to plague eastern MN and western WI
early this morning. The stratus will lift northward, from east to
west leading to clearing skies. However, a secondary area of MVFR
cigs is quickly approaching the region from the northwest.
Guidance suggests it will break up and eventually fall apart
through the day. Winds today will generally be W or WSW of around
15G23kt.

KMSP...No additional concerns.

/OUTLOOK FOR KMSP/
Mon...VFR. Wind SW at 10-15kt.
Tue...VFR. Wind N at 5 kts.
Wed...MVFR with SN possible late. Wind E at 5 kts.

&&

.MPX WATCHES/WARNINGS/ADVISORIES...
WI...None.
MN...None.
&&

$$

SHORT TERM...SPD
LONG TERM...JRB
AVIATION...SPD



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