Area Forecast Discussion
Issued by NWS Twin Cities, MN

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FXUS63 KMPX 111729

Area Forecast Discussion
National Weather Service Twin Cities/Chanhassen MN
1129 AM CST Sun Feb 11 2018

.SHORT TERM...(Today and tonight)
Issued at 255 AM CST Sun Feb 11 2018

The main storm track will remain well off to our southeast during
the short stream, but a northern stream wave dropping down from
Canada will bring us another re-enforcing shot of arctic air this
afternoon. There`s no moisture to work with, so this wave will mean
nothing more than an uptick in mid/upper level clouds, but we will
be seeing low level CAA kicking in by the afternoon, so did knock
back highs a few degrees from what we had going. Similarly, trimmed
lows tonight a few degrees from the previous forecast, with another
sub zero morning expected Monday across the entire area. Of course
these cooler temperatures will bring back the threat of needing a
wind chill advisory tonight across our northern tier of counties
from central MN into northwest WI. Looks marginal, but is something
we`ll let the next shift take a closer look as it won`t take much of
a nudge in the forecast in terms of temperatures or winds to send
apparent temps mostly warmer that -25F (no advisory) or colder than
that (advisory needed).

.LONG TERM...(Monday through Saturday)
Issued at 255 AM CST Sun Feb 11 2018

What the long term does not include is any significant precipitation,
but it does offer a couple of brief breaks from this relentless cold
Wednesday and again next weekend.

Model agreement remains good through Wednesday, with split flow
developing as the compact upper low currently west of Seattle
becomes cut off from the flow Monday night over California. Model
continuity and agreement continues to suffer after Wednesday as the
two streams phase, with an impressive jet of over 200 kts developing
over the Great Lakes post merger. Though there are differences,
there is at least general agreement that we will see heights build
over the weekend as that phased jet works east, before the jet
stream takes a dive back south of the upper Midwest and we head back
into a below normal pattern.

We will start the long term with a cold arctic high, which means
another day of highs in the single digits and teens Monday. We`ll
get into return flow Monday night, with a small chance of seeing
some precip in western/central MN Monday night into Tuesday morning.
Does not look like anything impressive and forcing is fast moving
and may not stick around long enough to allow the atmosphere to
moisten enough to allow precip to reach the ground.

Tuesday we`ll finally see highs near normal as southwest winds kick
in and this WAA looks to carry straight into Wednesday. Wednesday
still has all the looks of an overachieving day for highs, with
southwest winds developing ahead of a cold front. SuperBlend has
widespread highs in the 40s now for Wednesday, though there is
potential for highs to still get warmer than this, as those
southwest winds will keep any stratus/fog at bay (southeast winds
would be a different story) and skies mostly sunny.

After Wednesday, we start to see large timing differences on when
the next shot of arctic air arrives.  The GFS has it blasting
through here Wednesday night, but the ECMWF holds off until Thursday
afternoon/evening, so there`s large spread in potential highs for
Thursday ranging from mainly the teens (GFS) to still getting into
the 30s (ECMWF). There`s also little continuity on if this return of
arctic air will bring any light snow with it as well, so kept the
forecast dry for Thursday-Friday as well.

For the weekend, we should quickly see highs rebound back to near to
above normal as heights build and we transition to a WSW flow,
though the weekend looks to end with you guessed it, another arctic

For precip, any chances look fleeting locally until the week of the
19th. That week, the GEFS/EPS show ridging becoming quite strong
from the Bahamas up toward Newfoundland. This would result in a
rather wet and active pattern to the west of the ridge. Depending on
how far west this ridge axis sets up will determine whether we end
up with more cold and dry weather, or if we open up the door to
seeing southwest type systems again.


.AVIATION...(For the 18Z TAFS through 18Z Monday afternoon)
Issued at 1125 AM CST Sun Feb 11 2018

MVFR cigs upstream across northwest Minnesota may provide an hour
or two this afternoon of MVFR cigs in central Minnesota. However,
these clouds are very scattered and most areas will remain VFR.
Winds will shift to the west/northwest this afternoon with gusty
winds likely through early evening, especially in central/west
central Minnesota where the best mixing in the boundary layer
occurs this afternoon. Otherwise, VFR conditions overnight with
winds becoming light and variable Monday morning.


No additional concerns, with only a brief time frame of MVFR
clouds after 21z thru 02z. Confidence remains high that VFR
conditions will continue. Winds will shift to the west-northwest
and begin to gust above 18 kts this afternoon.


Mon Night...VFR. Winds SE 5 kts.
Tue...Chc MVFR in aftn. Winds SW 10 kts.
Wed...VFR. Winds SW 10 kts.




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