Area Forecast Discussion
Issued by NWS Twin Cities, MN

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FXUS63 KMPX 170954

Area Forecast Discussion
National Weather Service Twin Cities/Chanhassen MN
354 AM CST Fri Nov 17 2017

.SHORT TERM...(Today and tonight)
Issued at 355 AM CST Fri Nov 17 2017

Light precipitation is occurring over the west central Wisconsin
portion of the forecast area this morning, in response to weak
moisture advection north/east of a warm front edging into
southwestern Minnesota. So far either light rain or light snow has
been observed, but cannot entirely rule out a brief window of
light freezing drizzle this morning over Polk/Barron/Rusk/Chippewa
counties where surface temps are currently at 32 degrees. Any
freezing precipitation would be light and brief, so ice
accumulations are not expected.

This afternoon a healthy band of 700-600mb frontogenesis develops
from central MN across southeast MN and west central WI. Expect
fairly widespread rain to occur, briefly mixing with snow tonight
prior to ending by daybreak Saturday.

Despite the blanket of stratus clouds, temperatures will be mild,
with highs in the upper 30s to mid 40s.

.LONG TERM...(Saturday through Thursday)
Issued at 355 AM CST Fri Nov 17 2017

For a time of year that can often have significant storm systems and
high impact weather, weather will be considerably lacking, with
no precip currently forecast through the entirety of the long term
period. Instead, the long term looks to be marked by fairly
progressive flow that will feature dry fropas every 2-3 days. Ahead
of these fronts, we`ll see highs poke up into at least the 40s, with
breezy northwest winds and highs in the 20s/30s in their wake.

We`ll start the long term in one of those cold NW wind patterns as a
surface low deepens on its trek across the Great Lakes, with high
pressure coming at us from the Plains. Though relatively cool, it
does look like the weekend will offer us periods of sun/clear skies
as the stratus will be quickly pushing off to our east Saturday
morning, with nothing but some passing mid/high clouds expected the
rest of the weekend. Monday will see a good surge of warm air.
Though this time, it will not come with dewpoints in the 40s, but
rather dewpoints staying back in the 20s. So this time around the
warm air will not come with dense stratus, but will rather have
mainly clear skies to work with. Based on 925mb temps between 6c and
10c and mainly sunny skies, could certainly see highs ending up a
few degrees warmer than what we have, with 50 not out of the
question even for the Twin Cities.

The warmth of Monday will be quickly pushed out though Monday night
as another strong cold front moves through. Monday night into
Tuesday looks similar to what we are expecting tonight, though winds
could be a bit stronger as the CAA really kicks in late Monday
night. This CAA will result in cool days Tuesday and Wednesday.
Depending on where a surface ridge axis sets up Wednesday morning,
we could certainly see lows dip into the single digits in spots.

For Thanksgiving we get back into a WAA regime and like Monday, our
current forecast is on the conservative side of the envelop for max
temperatures, with the next cold front coming through either
Thursday night or later in the day Friday. At either rate, the
second half of the holiday weekend looks to be considerably colder
than the first half.  The good news though is through all of this,
we only look to be dealing with Pacific moisture that the Rockies
will have adequately rung out of the atmosphere before getting here.
In fact, the full 10 days of the Canadian/GFS/ECMWF show no
additional precip locally after what we get past today/tonight.


.AVIATION...(For the 06Z TAFS through 06Z Friday night)
Issued at 1127 PM CST Thu Nov 16 2017

Low clouds have been eroding across most of southern and central
MN, with some MVFR still from north of KSTC to northwest WI. These
should continue slowly moving northward and eroding.

Main concern will be incoming and developing MVFR/IFR with reduced
visibility in drizzle. This should be widespread by 15z across
central and southern MN and western WI. One large batch has been
moving north-northeast out of Oklahoma and eastern Kansas, while
some has also been developing over central Iowa. A third area in
southwest Wisconsin and far southeast MN may clip KEAU before
12Z, but this is uncertain. Regardless, short term models have
been in excellent agreement as to timing of low clouds. Have gone
with IFR ceilings for all but west central MN.

Incoming cold front from the northwest will enter west central MN
around 15Z. Lowest level will dry out slightly and ceilings should
lift, but it will take a few hours.

KMSP...Expecting MVFR to develop around 14Z, with IFR quite likely
soon thereafter, probably around 16Z. Confidence is above average,
although timing may vary by an hour or two. Drizzle should begin
late Friday morning and persist through the afternoon as surface
low approaches from the southwest and gradient weakens. Improvement
to MVFR will not take place until later Friday evening, a few
hours after front from the northwest has moved through.

Sat...VFR with MVFR early. Wind NW 10-20 kts.
Sun...VFR. Wind SW-W 5-10 kts.
Mon...VFR. Wind S 5-10 kts.




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