Area Forecast Discussion
Issued by NWS Twin Cities, MN

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FXUS63 KMPX 250824

Area Forecast Discussion
National Weather Service Twin Cities/Chanhassen MN
324 AM CDT Thu May 25 2017

.SHORT TERM...(Today and tonight)
Issued at 315 AM CDT Thu May 25 2017

Surface analysis early this morning shows one low pressure system
over the central Ohio Valley region with another over the far
western Dakota. In between, weak high pressure prevails over the
Upper Mississippi River Valley. Aloft, one large upper level low is
located nearly atop the surface feature in the Ohio Valley while a
second large upper level low is sitting over southern Saskatchewan
province. In between, an upper level ridge axis extends from western
Ontario province southwestward to the TX/OK panhandle area. The
ridge will be the primary feature driving the sensible weather over
MN/WI today with a mix of sun and clouds along with comfortable high
temperatures around 70 degrees. The ridge will move off to the east
tonight, allowing the warm front from the western low pressure
system to pivot north into southern Minnesota by this evening and on
into central Minnesota tonight. In addition, the trailing cold front
is expected to push east through much of the state tonight, moving
to nearly the MN/WI state line by daybreak Friday. While deep
moisture will not be considerably high, there will be enough
moisture available for the frontal system to use for generating at
least isolated showers this afternoon through tonight from west to
east. Not looking for much in the way of QPF at all, maybe a
hundredth or two for most spots if anything at all. As for
temperatures, after the highs of around 70 today, the additional
clouds plus the passage of the warm front will keep temperatures
mild for tonight with lows in the 50s.

.LONG TERM...(Friday through Wednesday)
Issued at 315 AM CDT Thu May 25 2017

The long term concerns remain timing of frontal passage Friday and
overall evolution of the long wave trough/closed low over the
northern CONUS over the holiday weekend and early next week.

The front progresses east over the cwa during the day Friday. We
will hold onto the chance PoPs for this feature with thunder
chances into the afternoon. By tomorrow evening, the front will
have advances well into west central Wisconsin and should end the
rain threat in the evening there. Temperatures looks warm
along/ahead of the front with rising in the mid/upper 70s across
far southern MN. More clouds to the north will limit heating
somewhat with readings around 70 common there.

Into Saturday, we may see some elevated showers linger to the
south during the day and then some encroachment to the northwest
in the afternoon as the upper trough approaches. Appears the GFS
is a little overdone on overall development into Saturday. We like
the drier ECMWF and Canadian model at this point as the upper jet
translates a bit farther to the southeast.

We still see some timing differences in the overall evolution of
the upper trough over the northern state. This will affect timing
of the cold front and development of more widespread cloudiness.
The GFS appears to be overdone on its leading short wave into
Sunday. We like the slower ECMWF/Canadian models which favor the
front to drop into the area Sunday afternoon and across the area
by Memorial day. At the moment PoPs are probably a little low with
the trough moving in during this period. Hopefully, the models
will come to a consensus on this system during the day.

Temperatures are expected to remain in the lower 70s both
Saturday and Sunday, which is close to normal. However, with the
passage of the front, readings will cool back about 10 degrees
below normal again on Memorial Day.

Following this, we remain on the cool and mainly dry side into
midweek with a warming trend indicated later next week as ridging
aloft/warmer air builds over the western CONUS.


.AVIATION...(For the 06Z TAFS through 06Z Thursday night)
Issued at 1057 PM CDT Wed May 24 2017

VFR conditions are prevailing now but MVFR ceilings are inching in
from the west now that low level winds are shifting to easterly in
direction. Expect the MVFR ceilings to reach KRNH and KEAU, but
will more likely be of a scattered nature to the west at KMSP.
There could also be IFR/LIFR visibility restrictions due to
BR/fog (primarily at KRNH/KEAU). After 18z Thursday isolated
showers will be possible (primarily in western MN), with the
slight chances expanding eastward during the afternoon.

Still do not think MVFR ceilings look quite as likely as they did
for Wednesday morning, so have kept it at a FEW-SCT mention. Any
broken layer would more likely be above 1800 ft. Winds veer to
southeasterly overnight with some gusts into the mid teens (knots)
developing by late morning Thursday. Isolated showers could near
the field by 00z Friday, but the probability/coverage is too low
to warrant inclusion in the TAF at this point.

Sat...Mainly VFR. Slgt chc P.M. -SHRA/-TSRA. Wind W 5-10 kts.
Sun...Mainly VFR. Chc -SHRA/-TSRA. Wind NW 5-10 kts.
Mon...MVFR possible. Chc -SHRA/-TSRA. Wind NW 5-10 kts.




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