Area Forecast Discussion
Issued by NWS Twin Cities, MN

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FXUS63 KMPX 170854

Area Forecast Discussion
National Weather Service Twin Cities/Chanhassen MN
354 AM CDT Mon Apr 17 2017

.SHORT TERM...(Today and tonight)
Issued at 354 AM CDT Mon Apr 17 2017

A weak trough generated an increase in mid-level clouds overnight,
along with a few sprinkles over parts of central and southern MN.
Skies will clear fairly swiftly in the wake of this feature today
as a ridge of surface high pressure drifts across northern MN.
Winds will also be much lighter today as a result. Less mixing
today therefore with an unfavorable directional component for
warming. Therefore highs, while still relatively close to normal
values for mid-April, will be cooler. Expect highs to range from
the lower 50s into central MN to lower 60s along the Iowa border.

The forecast gets more active again tonight as a compact mid-level
low/trough races from the northern Rockies across the Dakotas and
across northern MN/WI on Tuesday. Isentropic omega on the
300-305K surface blossoms over west central MN around 06z, then
ensues to the east as the wave passes. Confidence is pretty high
given model consistency/agreement with this feature, so have
included 80 percent chances of showers and thunderstorms in
central MN (along/north of I-94), and 60-70 percent chances to
the south. By daybreak Tuesday, expect the eastern edge of the
activity to be near the MN/WI border. Given the swift nature of
this activity, do not expect a significant amount of rainfall
overnight, but a quick one quarter to half inch of rain is likely.

.LONG TERM...(Tuesday through Sunday)
Issued at 354 AM CDT Mon Apr 17 2017

Two systems will affect the Upper Midwest over the next few days.
Overall, these two systems will be the most unsettled/wettest in the
next 7 days as the pattern changes by late in the week.

First, the fast progressive nature of tonights system will bring a
fairly narrow, and fast band of convection Tuesday morning. It will
likely exit most of Minnesota by noon, and west central Wisconsin by
mid afternoon. Deeper moisture will reside in northern Minnesota, so
precipitation amounts will be low /under a quarter of an inch/ and
last an hour or two during the morning from west to east.
Instability is weak, so any thunderstorm activity will be isolated
at best.

On the heel of Tuesday`s system, another fast moving short wave will
begin to affect southern Minnesota Wednesday morning. Previous model
runs had differences in the phasing of two waves Wednesday. However,
these differences are not quite as strong as in previous runs, and
both the GFS/EC have a similar scenario. Only the GEM is more
progressive with the southern short wave and weaker by Wednesday
night. As per the EC/GFS, the southern short wave is stronger and
slower than the GEM. This could be related on the lack of phasing
with the upstream short wave. One concern is the strengthening of
the southern wave which may lead to some mixture of snow early
Thursday morning before temperatures rise. There isn`t any threat of
accumulating snowfall, but strong enough for a very cold rain/mixed
with snow Thursday morning before this system moves off to the east
Thursday afternoon. Depending upon how fast/slow this system moves
off to the east Thursday, temperatures could linger in the 30s/lower
40s for afternoon highs, especially in west central Wisconsin. These
colder temperatures could also mean a freeze or heavy frost Friday
morning. Although the Upper Midwest usually has a frost or freeze as
late as late April, the recent warm temperatures has caused
vegetation to bloom. Those with tender plants may want to bring them
in Thursday night.

In the wake of Wed/Thu system, a drier and cool period expected
through the weekend. Typically, highs rise into the 60s by mid/late
April, with lows in the 40s. This weekend could see highs only
rising into the 50s and overnight lows in the 30s to around 40.


.AVIATION...(For the 06Z TAFS through 06Z Monday night)
Issued at 1047 PM CDT Sun Apr 16 2017

VFR conditions throughout. Clouds with bases around 10kft will
pass overhead. Light northwest winds will become calm on Monday
and eventually take on a southeasterly direction late Monday ahead
of the next system that will spread rain across the region early
Tuesday morning.

VFR conditions throughout. Precip chances will return around 12Z
on Tuesday, but did not include mention in the taf for this

Tue...MVFR and -RA with IFR/TSRA possible in morning. Wind SSW
 bcmg W in afternoon at 10G20kt with dry conditions.
Wed...VFR with -RA/MVFR Cigs likely overnight. Wind NE at
Thu...MVFR Cigs possible early then VFR. Wind NE at 5-10kt.




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