Area Forecast Discussion
Issued by NWS Twin Cities, MN

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FXUS63 KMPX 181053

Area Forecast Discussion
National Weather Service Twin Cities/Chanhassen MN
553 AM CDT Thu May 18 2017

.UPDATE...For 12z Aviation discussion below


.SHORT TERM...(Today and tonight)
Issued at 330 AM CDT Thu May 18 2017

The compact low responsible for yesterday`s tornadoes, severe
weather, and heavy rainfall has lifted to the Great Lakes early this
morning. Light to moderate deformation rains continued across much
of the area overnight in its wake. Precipitation will taper off by
noon-time today as temporary mid level ridging builds in between the
aforementioned system and the next in the parade (which was located
near the Four Corner`s region overnight).

High temperatures today will be on the cool side of climatological
normals with relatively low heights and lingering low clouds.
Readings will top out from 50-60 degrees and be accompanied by
northerly winds.

Tonight winds do begin to decrease and skies clear briefly as
surface high pressure over northern Minnesota begins to drift south.
This is expected to allow temperatures to cool into the 30s north of
the I-94 corridor, which will mean frost concerns will heighten.
Given a bit of uncertainty with cloud trends (given clouds will be
moving back in from the west ahead of the next system), and
considering winds look to stay up around 5 knots, the extent of
frost isn`t a slam dunk. Therefore have held off on a frost advisory
until these factors are refined.

We will have rain showers creeping toward south/west central MN
during the early morning hours, but the activity currently looks to
hold off until after daybreak Friday.

.LONG TERM...(Friday through Wednesday)
Issued at 340 AM CDT Thu May 18 2017

The next storm system will begin to affect the Upper Midwest
Friday with an area of low pressure developing across the plains,
and moving northeast across the Upper Midwest over the weekend.

Overall, models have a good handle for the next storm system. The
main differences is timing of the heavier/steadier precipitation
which looks to hold south of the Iowa/Minnesota border until
Friday evening. Deeper moisture and upper level energy which will
be associated with the upper trough/low moving northeast across
the Upper Midwest late Friday night/Saturday morning. Some minor
differences on the placement of the upper trough/low is noted on
Saturday, but these differences are mainly for the displacement of
the deformation zone in western Minnesota Saturday

Based on current model trends, late Friday night/Saturday
morning, mainly before noon, will be the best time frame of
widespread shower activity and heavier rainfall. Depending upon
where the deformation zone /precipitation/ develops, will
determine temperatures and if Saturday afternoon could be dry for
several hours. There remains enough differences to hold onto 50s
for high temperatures Saturday, but 60s are not out of the
question in south central/southeast Minnesota, and into parts of
west central Wisconsin if the upper low moves further to the west.

Due to the persistent upper trough holding across the eastern half
of the nation, and some indications of the upper low holding
across the Great Lakes region through early next week, continued
cooler than normal temperatures will remain in our region. I
wouldn`t be surprised to not see another 70 degree temperature
until next Tuesday or Wednesday based on the upper level flow and


.AVIATION...(For the 12Z TAFS through 12Z Friday morning)
Issued at 553 AM CDT Thu May 18 2017

Areas of light rain will linger this morning, along with MVFR
ceilings. Expect precipitation to have ended by the 18z issuance,
although MVFR ceilings will likely persist for much of the
afternoon (with the exception of northern sites, KAXN and KSTC
which will scatter out by early afternoon). Mostly clear skies
then prevail for this evening and tonight, but look for increasing
clouds and precip chances returning on Friday. Gusty north-
northeast winds look to gradually diminish during the afternoon
and evening.

Expect cigs to improve above 1800 ft by late morning, but a deck
circa 2KFT will likely linger through much of the day. Gusty north
winds decrease below 10 knots for this evening.

Fri...VFR with MVFR/-SHRA possible late. Wind NE at 10kt
Sat...MVFR/RA with IFR possible. Wind E at 10G20kt
Sun...MVFR early. Wind WNW at 15G25kt




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