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FXUS63 KMPX 202031

Area Forecast Discussion
National Weather Service Twin Cities/Chanhassen MN
331 PM CDT Sun Oct 20 2019

.SHORT TERM...(This evening through Monday night)
Issued at 332 PM CDT Sun Oct 20 2019

Forecast concerns for the short term are precipitation timing and
extent of convective threat into Monday. Then remain wind becomes
an issue late Monday afternoon/night. 

Thicker high clouds moving into the area now, but not fast enough to 
hold temperatures from warming through the mid and upper 60s over a 
portion of central MN. This should be the last mild day as the next 
storm system is poised to affect the region. Slowed the eastward 
progression of the precipitation band. It should work into eastern 
MN by 12z Monday.  Isentropic lift becomes maximized over eastern MN 
08z-12z period. Some threat of thunder with this activity later 
tonight. Will hold onto slight chance thunder for now. This works 
east during the day Monday as the surface low tracks close to east 
central MN. Dry slot may work into southern MN Monday afternoon and 
we decreased PoP some to account for this possibility.

As the low lifts east/northeast and occludes over eastern MN late 
Monday afternoon, we expect wind to increase over the western CWA 
before 00z Tue. Model soundings suggest 45-50kt gust potential from 
the northwest over west central MN Monday night. Strong pressure 
gradient and CAA should allow winds to reach close to that 
potential. We decided to hold off on headlines for the moment. One 
more model run to hone in on finer timing details with regards to 
surface low. 

Colder air moves into the region Monday night, possible cold enough 
to mix in some wet snow over the northwest CWA after 06z Wed. 
Accumulation isn't expected. 

.LONG TERM...(Tuesday through Sunday)
Issued at 332 PM CDT Sun Oct 20 2019

Unsettled weather continues into the start of the long term period
on Tuesday and Wednesday, and then benign conditions arrive for
the last half of the week. 

A very tight surface pressure gradient looks to remain situated
over the area until at least mid-day Tuesday. NAM/GFS Bufkit both
indicate 40-50 knots at the top of the channel through Tuesday 
morning, with gradual decrease on Tuesday afternoon as the trough 
shifts farther into Ontario and the gradient relaxes. Temperatures
will only moderate a few degrees Tuesday given the low level cold
air advection and cloud cover/showers under the cyclonic flow 
regime. Highs will top out in the low/mid 40s, with chilly 
apparent temperatures in the 30s. 

On Wednesday we quickly shift into westerly large scale flow. GFS
and ECMWF models continue to forecast a weak shortwave/PV feature
sliding from the Plains to MS Valley region as we transition to 
an eastern trough/western CONUS ridge pattern. Have included 
chance POPS for a rain/snow mix associated with this feature, and 
although attendant precip amounts would mostly likely be light, 
could envision higher POPs once strength/timing/track details are
more certain. At this point southern areas (along/south of the MN
River Valley) look to be favored.

From Thursday into the first half of the weekend, surface high 
pressure dominates the region, and brings a dry forecast with 
gradually moderating temperatures. Expect highs in the low/mid 50s
for Saturday.

By Sunday, notable differences in the models evolve with regard to
the large scale pattern, but at this point we look to stay removed
from forcing mechanisms for precipitation.  


.AVIATION...(For the 18Z TAFS through 18Z Monday afternoon)
Issued at 1230 PM CDT Sun Oct 20 2019

KEAU finally broke free of the LIFR FOG and stratus around 1530z.
They should be VFR until late tonight. Mid/high level clouds 
moving into the area this afternoon. Lowering cigs to MVFR as the 
bands of -ra moves from west to east through 12z Monday. As 
developing surface low moves into southern MN late tonight, will 
likely see return of more widespread IFR cigs. THis may improve to
the south Monday afternoon before wraparound clouds/showers move 
back into late Monday/Monday night. Surface winds SE-E ahead of 
the developing low. May become gusty into the evening over much of
the areas as the low begins to deepen. Expect a wind shift to 
NE-N and eventually NW as the low travels east Monday afternoon, 
with winds increasing and gusty over the western area by 00z Tue.

KMSP...VFR trend until beginning of rain, sometime around 08z.
Then MVFR lowering to IFR cigs by 13z. Expect improving to MVFR 
again through about 18z Mon. May see a break in the more 
widespread rain or taper to periodic drizzle into the late 
morning/early afternoon before more wraparound rain moves in 
during the afternoon.

Mon night...IFR/-SHRA. Bcmg MVFR. Wind SW 5-10 kts bcmg 
NW 20G30 kts. 
Tue...MVFR chc IFR. -SHRA likely. Wind NW at 25G35 kts.
Wed...Chc MVFR/-SHRA. Wind NW at 15G25 kts. 



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