Area Forecast Discussion
Issued by NWS Twin Cities, MN

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FXUS63 KMPX 190350
AFDMPX

Area Forecast Discussion
National Weather Service Twin Cities/Chanhassen MN
1050 PM CDT Tue Apr 18 2017

.SHORT TERM...(This evening through Wednesday)
Issued at 249 PM CDT Tue Apr 18 2017

A busy weather day today with a low pressure system screaming east
through central MN.  Widespread showers and some thunderstorms have
come to an end, but more showers and thunderstorms will be on the
way tomorrow with the next system.

The winds will remain gusty through the daylight hours before
diminishing overnight.  The tough part of the forecast is whether or
not the low clouds hang around as high pressure builds in from the
northwest.  The clouds could become trapped under the inversion and
stratus linger all night.  On the flip side, the guidance has
repeatedly overdone low level moisture this spring, leading to a
more pessimistic forecast than reality has shown.  Leaning toward
mostly mid and high clouds, with fog possible when winds become
lighter overnight.

For tomorrow, more rain is forecast to move in, from the south this
time.  This next system will lift northeast out of Colorado with the
warm front advancing through much of Iowa.  Widespread rain to the
north of the front, along with weak elevated instability will lift
into southern MN in the afternoon.  Raised pops to near 100% in this
area where agreement is very high among the models.  Thunder should
be scattered or isolated and we do not expect severe weather at this
time.

.LONG TERM...(Wednesday night through Tuesday)
Issued at 249 PM CDT Tue Apr 18 2017

The longer term concerns remain timing/development of the trough
through the region Wednesday night into Thursday. Then some threat
of frost later Thursday night over the northeast cwa and possibly
Sunday mornings well.

The longer term deterministic models drive the upper trough east
across the area into Thursday morning. This will promote categorical
PoPs across most of the area Wednesday night and trailing to the
east through Thursday morning. Clouds are expected to remain most of
the day to the east and will limit overall heating potential to the
east Thursday afternoon. Drier air works in then Friday night as
high pressure drops south. This should promote a clearing sky and
light winds. Temperatures should be able to cool to the lower 30s
across the north and east cwa by Friday morning with some frost
potential. Still have time to monitor model trends as the GFS is
trying to force a secondary wave dropping in behind the retreating
trough.

Following this system we should see dry and warmer conditions
developing into the weekend. The models continue to show a weak cold
front dropping into the region later Saturday night into Sunday but
it appears weak at this time. We retained the small chance of
showers over mainly across the northern cwa Saturday night and again
Sunday night. The next trough moves into the area Monday into
Tuesday.

&&

.AVIATION...(For the 06Z TAFS through 06Z Wednesday night)
Issued at 1050 PM CDT Tue Apr 18 2017

MVFR ceilings continue to hold across much of MN and western WI
late this evening. This bodes well for the previous TAF cycle
on keeping ceilings MVFR. Therefore, little change was made to
the previous TAF`s, with the exception of allowing for some IFR
ceilings near daybreak for a few hours at most sites. The timing
on the -RA and SHRA remains on track with high confidence that
during the late afternoon and evening MVFR ceilings and
visibilities will be widespread in the precipitation. TSRA chances
late Wednesday and Wednesday evening still seem to be confined
from south central MN through west central WI, including the Twin
Cities. Light NW winds overnight becoming NE early on Wednesday
and then more E at 12-16 knots for Wednesday afternoon and
evening.

KMSP...Maintained MVFR ceilings through the period. A growing
concern is the threat of IFR ceilings about 2 hours either side of
12z. Used SCT008 to indicate the threat at this point. Otherwise,
widespread SHRA and isolated TSRA still expected from 22z on
through the evening.

/OUTLOOK FOR KMSP/
Thu...MVFR ceilings likely. CHC of SHRA early. Wind NW 10-15kts.
Fri...MVFR ceilings possible early then VFR. Wind NE 5kts.
Sat...VFR. Wind light and variable.

&&

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

$$

SHORT TERM...SPD
LONG TERM...DWE
AVIATION...RAH



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