Area Forecast Discussion
Issued by NWS Twin Cities, MN

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FXUS63 KMPX 170430 AAC

Area Forecast Discussion...UPDATED
National Weather Service Twin Cities/Chanhassen MN
1030 PM CST Fri Feb 16 2018

Issued at 744 PM CST Fri Feb 16 2018

Hi-res models (HopWRF, HRRR, RAP) are in good agreement in a band
of snow developing very late tonight over south central MN (in
the vicinity of Mankato) and spreading northeast into Saturday
morning. The northwest edge appears to be roughly from Redwood
Falls, to the metro, and New Richmond and Rice Lake, WI. One to
two inches are possible. PoPs have been increased to at least 70%
and QPF/snowfall amounts have been adjusted accordingly. Updates


.SHORT TERM...(This evening through Saturday)
Issued at 314 PM CST Fri Feb 16 2018

Early this afternoon the center of a large surface high was
centered over the southeast corner of Nebraska, with clear skies
and below normal temperatures across southern MN and western WI.
Today demonstrated the importance of surface albedo this time of
year, as western MN and it`s snow-free ground saw temperatures
rise into the upper 20s. Not too far away, in places such as New
Ulm, Mankato, and the Twin Cities, the snow pack held temperatures
in check with afternoon readings ranging from 10 to 15 degrees.

The high pressure will slide to the east tonight with southerly
winds continuing through the night.  While it won`t necessarily be a
warm night with the cool airmass in place, overnight temperatures
will bottom out in the teens, near normal for this time of year.

Tomorrow a quick moving upper level shortwave will move through from
west to east, and weak isentropic lift will bring some light snow to
the area during the day.  Accumulation is generally not expected,
except in west central WI where up to an inch of snow could fall
later in the day.

.LONG TERM...(Saturday night through Friday)
Issued at 314 PM CST Fri Feb 16 2018

Not a lot has changed from the previous forecast with the Sunday-
Tuesday timeframe in terms of the evolution of the system and the
deep trough to the west.  We still expect some freezing rain to be a
possibility from the metro and south.  The highest ice potential is
along I-90, so it will be something to watch.  The snowfall
potential with this system is not real impressive. The initial
wave that ejects from the main longwave trough over the western
CONUS will move across North Dakota and northern Minnesota. It
could graze central MN from Alexandria to Mille Lacs with 1-3" of
snow. South of there, accumulation will go from less than an inch
to zero by the time you get south of St. Cloud.

So, Monday is the best potential for area-wide precip.  Thermal
profiles look warm enough at about 800H to melt snow into liquid
form, and with temperatures around 30 or colder, freezing rain still
looks likely.  The QPF did come down some from the previous shift.
There looks to be a few inches of snowfall accumulation across much
of central MN, but the chance for ice accumulation is more of a
concern, albeit a slight jog south with the evolution of the system
would keep our entire area in snow as the primary p-type.

Beyond that, temperatures will cool below normal once again for
midweek, with a warming trend looking more likely near the end of
the forecast period.


.AVIATION...(For the 06Z TAFS through 06Z Saturday night)
Issued at 1030 PM CST Fri Feb 16 2018

The band of snow has shifted north a bit from previous forecasts
for late tonight and Saturday morning and now impacts RWF, MSP,
and RNH more. In fact, 1 to 2 inches are possible with IFR
conditions at MSP and RNH in addition to MKT and EAU.

KMSP...Will lower visibilities to IFR levels between 11-14Z with
the expected band of snow this TAF issuance. Snowfall rates of
1/2 to 1 inch per hour could occur if the band develops as
currently expected. Will continue to watch it overnight with
amendments made as necessary.

Sun...VFR. Winds SE 10 kts becoming SW late afternoon, then NE
during the evening.
Mon...IFR/-SN likely. Winds NE 10-20 kts.
Tue...Chc MVFR/-SN. Winds N 10 kts.




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