Area Forecast Discussion
Issued by NWS Twin Cities, MN

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FXUS63 KMPX 271730
AFDMPX

Area Forecast Discussion
National Weather Service Twin Cities/Chanhassen MN
1230 PM CDT Mon Mar 27 2017

.SHORT TERM...(Today and tonight)
Issued at 335 AM CDT Mon Mar 27 2017

A rather convoluted pattern across the region early this morning.
The upper level low that was south of us yesterday morning at
this time is now over the western Great Lakes. The band of
precipitation that we had on the backside of the low, to the west
and north of the Twin Cities, is now a narrow band from northeast
of the Twin Cities through northwest WI. The precipitation will
move off slowly to the east this morning in concert with the upper
low. Therefore, had to include a small area of likely pops for a
time early this morning as a result. A ridge of high pressure over
the Dakotas will work into the western FA during the afternoon
and then cover the region tonight. Some sunshine will develop
across central and northwest areas of MN today. The south and east
will be hard pressed to see much sunshine due to a second strong
short wave/upper low over the central/southern Plains that is
moving rather briskly to the ENE. This is going to aid in keep the
low ceilings stuck over the eastern and southern FA until
tonight.

Highs today will be warmest in the NW FA and coldest in the SE FA
due to the cloud and low level thermal pattern. Went with
highs in the mid to upper 50s across west central and portions of
central MN where 925 MB temperatures are progged to reach 10 C. This
setup in the ND on Sunday with some sunshine yielded highs around
60. Highs in the middle 40s to lower 50s were used to the east and
south.

Low tonight are expected to drop off into the mid/upper 20s across
central MN and west central WI with high pressure overhead at
daybreak Tuesday. Lows in the lower to middle 30s are common to the
south and west. Still concerned about the fog potential tonight.
Hydrolapse data is pretty vertical until right before sunrise when
there is a little increase in specific humidity in the 100-200 foot
level. Hence, indicated some fog development in the 09z-12z
period.

.LONG TERM...(Tuesday through Sunday)
Issued at 335 AM CDT Mon Mar 27 2017

Longer term trends continue the overall model differences in
handling the overall split flow upper level flow pattern and the
ejection of the closed low to the south in the Wed-Thu night
time.

We start out with plenty of sunshine and highs in 50s for Tuesday.
Mix down did bring some upper 50s over the MN portion of the cwa.
The next cutoff circulation over the southern stream will move
east into the Mississippi River valley by WEdnesday. There is some
interaction with the northern stream trough which does tend to
phase some with the southern circulation. THis should at least
lift some clouds into the region during the day Wednesday...along
with a small chance of light rain over the southern cwa. We will
hold onto chance PoPs for now. The low ejects to the
east/northeast Wednesday night as both the GFS and ECMWF drop
another strong trough into the west then. This should spread light
rain into far southern MN and perhaps northeast toward Eau Claire
during through Thursday. We did mention some likely PoPs over the
southernmost tier of counties. Colder air filters into the
region...and there could be at least a rain/snow mix as the
precipitation moves east into Thursday morning. Expect a lot of
cloud cover as the system moves through...mainly to the south.
This will limit temperatures some with lower and mid 40s common to
the southeast. The GFS is furtherest south with the rain
threat...with both the ECMWF and Canadian models drawing some
moisture into the southern metro during this period.

This system pulls east Friday...and we should see more sunshine
lingering through at least Saturday. The northern stream brings a
weak front into the area sometime Sunday. Moisture is limited
however...and we will retain a slight chance for this feature for
now. Temperatures will warm through the 50s over the entire
region for the weekend...with the above normal temperature trend
continuing into early April.

&&

.AVIATION...(For the 18Z TAFS through 18Z Tuesday afternoon)
Issued at 1225 PM CDT Mon Mar 27 2017

MVFR cigs affecting parts of southern Minnesota, and west central
Wisconsin will be the main aviation concern as
timing/dissipating this afternoon remains questionable. Based on
drier air advecting southward, and remnants of boundary layer
moisture holding near KEAU, the general trend of better conditions
by mid/late afternoon remains likely. Otherwise, later tonight
low clouds/fog will likely reform in south central/southeast
Minnesota and slowly spread east/northeast across eastern
Minnesota. Depth of the moisture remains shallow so only expect
some FG/BR for the most part during the typical morning hours
outside south central/southeast Minnesota and west central
Wisconsin. Winds will remain light from the north/northeast, and
more east Tuesday morning.

KMSP...

Main aviation concern is possible BR later tonight as boundary
layer moisture remains high, whereas mixing in this layer remains
weak. Based on overall trends, 4-5SM BR is likely during the pre
dawn hours. MVFR cigs will likely remain southeast of the
terminal, but close enough for later shifts to watch and possibly
adding to the taf. Winds will remain weak /under 8 kts/ from the
north/northeast this afternoon, and more east Tuesday.

/OUTLOOK FOR KMSP/

Wed...VFR. Chc -RA late. Wind ESE at 7-10kts.
Thu...VFR. Chc -RA. Wind E at 8-10kts.
Fri...VFR. Wind NE 4-8kts.

&&

.MPX WATCHES/WARNINGS/ADVISORIES...
WI...None.
MN...None.
&&

$$

SHORT TERM...RAH
LONG TERM...DWE
AVIATION...JLT



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