Area Forecast Discussion
Issued by NWS Twin Cities, MN

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FXUS63 KMPX 271039
AFDMPX

Area Forecast Discussion
National Weather Service Twin Cities/Chanhassen MN
539 AM CDT MON JUN 27 2016

.UPDATE...for 12z aviation discussion below

&&

.SHORT TERM...(Today and tonight)
Issued at 327 AM CDT Mon Jun 27 2016

The upper low over Ontario will bring cyclonic flow with increased
low cloud cover today, along with a few rain showers over west
central Wisconsin as a faint shortwave passes through the base of
the trough. The northwest flow will yield cooler temperatures, and
mixing to 875mb looks to generate highs from 65 to 70 (north of I94)
to between 70 and 80(south of I94).

Skies clear this evening and winds become light. Could see some
patchy fog with the surface high pressure centered over central
Minnesota and Wisconsin toward daybreak Tuesday.

.LONG TERM...(Tuesday through Sunday)
Issued at 327 AM CDT Mon Jun 27 2016

A relatively dry weather pattern will set up across the region
through the weekend. The only real chance for precipitation is late
Wednesday into Thursday, but don`t expect and widespread soaking
rains. Temperatures will be slightly below normal for late June and
early July.

Northwest flow will be in place across the region, bringing
subsidence and dry air. The upper level jet is pretty weak and
diffuse, meaning the speeds are only around 70 kts, and there is a
distinct break between the polar get across Canada, and the
subtropical jet that is rounding the persistent ridge over the
Desert Southwest. Also, the low level jet remains well to the south
over the Great Plains. For those reasons am not too optimistic in
widespread heavy precip Wednesday and Thursday.

Granted, there is a shortwave driving a cold front through the
region, so this should provide a focused area for ascent. Meanwhile,
forecast soundings show an uncapped environment with around 1000-
2000 J/kg of CAPE. With that said, do anticipate showers and
thunderstorms along and ahead of the cold front. The most
interesting part of these showers and thunderstorms is that if they
are post-frontal and manage to develop a mesocyclone, it should be
rotating anti-cyclonically given the backed wind profile off the
forecast soundings reflecting the cold air advection. In other
words, this set up could favor a left moving supercell, which is a
rarity for the Midwest. Truth be told, it is most likely the storms
will remain ahead of the front, and will have a veered wind profile
as one would expect in the warm sector. The severe threat is limited
due to the weak low level shear, and marginal instability. However,
the freezing levels will only be around 10 kft, so could get some
severe hail with a few of the stronger updrafts, but damaging wind
and tornadoes are unlikely.

Looking ahead, high pressure will follow for the weekend, with
return flow bring moisture over the Dakotas. The northwest flow will
deamplify and become more zonal, so could see showers and
thunderstorms try to make their way eastward into MN/WI by late
Saturday into Sunday. As of now though, generally speaking should
have a dry Independence Day weekend.

&&

.AVIATION...(For the 12Z TAFS through 12Z Tuesday morning)
Issued at 540 AM CDT Mon Jun 27 2016

The area of stratus over northern MN will begin to impact (all but
KRWF) TAF sites at the start of the period or shortly thereafter.
Expect cigs to degrade to between 2500 and 3500 feet this morning,
and then scatter out by mid/late afternoon (with VFR conditions
returning). Northwest wind will gust toward 20 knots for the
daytime hours, and then decrease below 5 knots this eve and veer
slightly to a more due north direction. There could be some light
fog toward daybreak Tuesday, but at this time the probability of
it occurring at the sites is too low to mention.

KMSP...A period of bkn cigs circa 3000 feet is expected this
morning, with a possibility of temporary (mvfr) reductions to 2500
ft. VFR is then expected for the bulk of the afternoon, with clear
skies by sunset. Winds gust into the lower 20s (knots) diminish
this afternoon with speeds decreasing below 5 knots this eve and
a shift to north-northeast winds.

/OUTLOOK FOR KMSP/
Tue...VFR. Light and variable wind.
Wed...VFR. Isolated SHRA/TSRA late. Southwest wind 5 kts.
Thu...VFR. Scattered SHRA/TSRA. Northwest wind 5 to 10 kts.

&&

.MPX Watches/Warnings/Advisories...
WI...None.
MN...None.
&&

$$


SHORT TERM...LS
LONG TERM...JRB
AVIATION...LS


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