Area Forecast Discussion
Issued by NWS Twin Cities, MN

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FXUS63 KMPX 192010

Area Forecast Discussion
National Weather Service Twin Cities/Chanhassen MN
310 PM CDT Mon Mar 19 2018

.SHORT TERM...(This evening through Tuesday)
Issued at 255 PM CDT Mon Mar 19 2018

A weak short wave was evident in the afternoon water vapor imagery
across the Dakotas, and Nebraska. This short wave, and associated
area of lift, especially in the dendritic growth zone, will be
centered in west central/southwest Minnesota late this afternoon,
and through the overnight period. The surface reflection is weak
and only a weak convergence zone in far western Minnesota
overnight is expected with this system. Thus, this is where the
best lift, moisture and convergence zone will highlight the area
of the best snowfall potential overnight. One to three inches in
likely in west central/southwest Minnesota, but amounts will
lessen significantly to the east as a persistent dry easterly flow
will limit the moisture depth. Slowly by morning, moisture will
deepen in eastern Minnesota which will allow for light snow to
develop. However, forcing is weak and most of the energy with the
system drops south into Iowa and slowly fades away. Therefore,
snowfall amounts will be less than an inch across eastern
Minnesota, with only trace amounts at best in far west central
Wisconsin. Temperatures will reflect the cloud cover and snow, and
overnight lows will be slow to fall. Daytime highs will be
cooler, especially along the Iowa border where cloud cover is more

.LONG TERM...(Tuesday night through Monday)
Issued at 300 PM CDT Mon Mar 19 2018

The main concern in the extended period is the potential of
accumulating snowfall, especially Saturday.

Most of the snowfall Tuesday afternoon will have ended, with a few
flurries possible Tuesday evening. The mean upper flow in our
region becomes more northwest as a deepening trough forms across
the eastern CONUS this week. Weak subtle waves will ride
southeast along this northwest flow, and may allow for some light
rain/snow in far southwest Minnesota on Thursday, but the bulk of
the impacted weather will stay far south of Minnesota.

Slowly the mean upper flow will become more amplified as an upper
ridge builds across the Rockies, and into the Northern Plains,
Upper Midwest by late in the week. The surface flow will slowly
become southeast, and increase in speed by Friday/Saturday as a
storm system begins to develop in the Rockies. This storm has the
potential of producing a considerable amount of precipitation over
the weekend, especially considering the long fetch of moisture
and the deep trough developing across the western CONUS.
Currently, there is a lot of model spread and uncertainties exist.
The latest model trends have the surface low further south across
Missouri than a few runs ago. Plus, thermal profilers are cooler
and this makes for a messy forecast. This system needs to be
watched closely as weather impacts are becoming likely. The main
impacts are the amount of precipitation (QPF), and snowfall. The
ground in Minnesota and western Wisconsin remains frozen and any
precipitation in the form of liquid water will run off quickly.
Thus, the potential of localized flooding exists. Secondly, the
snowfall could be significant is the atmosphere remains cool
enough during the strongest part of the system moving across the
area over the weekend. Stay tuned for further updates.


.AVIATION...(For the 18Z TAFS through 18Z Tuesday afternoon)
Issued at 1230 PM CDT Mon Mar 19 2018

Extensive mid-level cloud cover remains over the TAF area with
predominately northeasterly winds. Chances for snowfall and lower
ceilings will begin in Western MN this evening and arrive in
Eastern MN during mid-Tuesday morning. Due to fairly dry
conditions in place, snowfall intensity will weaken as it
progresses eastward. Thus IFR conditions are most likely at AXN
and RWF while EAU is expected to remain mostly dry and VFR.

KMSP... The 18Z TAF highlights the possible risk for snowfall and
MVFR ceilings Tuesday morning beginning at 10Z on Tuesday. Due to
dry, east- northeasterly winds, it may be possible that snow
chances will decrease. If there is indeed a drying trend, the TAF
will be updated accordingly.

WED... MVFR cigs possible early. VFR evening. Wind E 5 kts
becoming NW.
THU...VFR. Wind SE 5 kts.
FRI...VFR early becoming MFVR with pm -RA/-SN. Wind E 10 kt




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