Area Forecast Discussion
Issued by NWS Twin Cities, MN

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FXUS63 KMPX 161739 AAB

Area Forecast Discussion...UPDATED
National Weather Service Twin Cities/Chanhassen MN
1239 PM CDT Fri Jun 16 2017

.SHORT TERM...(Today and tonight)
Issued at 333 AM CDT Fri Jun 16 2017

The short term concern remains convective/severe weather this
afternoon and evening.

Latest radar loop showing some mid level accas showers moving across
southwest MN. This area of light showers/sprinkles will continue to
trek east this morning affecting much of the southern third of the
state. Not expecting anything measurable a 0.01 inch at best. This
return of mid level moisture is on the edge of some steeper mid
level lapse rates moving into the area along with some weak lower
level frontogenesis/waa. We expect a fair amount of mid cloud cover
during the day and this will determine overall heating/instability
for any more organized convection. Most deterministic models are
painting development into south central MN afternoon and exiting the
area during the evening. The latest HRRR is trending much faster
with initial development and a bit farther to the east. This is
trending more in line with the NCAR ensemble which has more
organized convection focusing more to the east and south of our cwa.
Chose to continue the chance PoP for the eastern cwa into the
afternoon/evening.  We will have to continue to monitor model trends
into the day for real confirmation of overall areal coverage of
development. If anything organized can develop into south central
MN...severe weather parameters are favorable for severe
weather...with deep layer shear around 50kts and MUCAPE to 1200 J/kg
in far south central MN. This is in line with the SPC Day1 outlook.

The activity will exit the area during the evening with PoPs trending
to slight chance overnight. Some form of clouds are expected to
linger as well and should hold temperatures up some tonight.

.LONG TERM...(Saturday through Thursday)
Issued at 333 AM CDT Fri Jun 16 2017

Saturday and Sunday...The period will commence with the WFO MPX
coverage area located between two frontal systems; one being a
cold front straddling the Canadian border with MN and ND, and the
other a frontal system over NE into IA. Upper level flow will be
generally zonal but there will be a potent upper level low
spinning just south of Hudson Bay. This upper low will pivot and
become oblong, thrusting a NE-SW oriented trough axis into the
Northern Plains by midday. This trough will then swing through the
Upper Mississippi River Valley Saturday evening while the northern
front dips into central MN and northwest WI. While the upper low
will have plenty of moisture concentrated around itself, the
developing trough axis will drag Pacific moisture into this
region, allowing the multiple disturbances and the surface and
aloft to generate precipitation, showers and thunderstorms, over
much of the area Saturday and Saturday night. Though the consensus
is to have limited instability for the bulk of the coverage area,
there are hints of MLCAPE into the 750-1000 j/kg range over far
southern portions of the area but severe potential overall remains
low. Precipitation is expected to wane in coverage and intensity
as the day progresses on Sunday, due to the departure of any
remaining shortwave trough aloft (replaced by drier northwest
flow) and the arrival of high pressure from the intermountain
west. Due to the high pressure containing a modified Canadian
airmass, temperatures will continue to go on a cooling trend
through the weekend, resulting in a brief bout of below normal

Monday through Thursday...Much of the first half of the week will
feature relatively drier and cooler northwest flow aloft while a
significant deep ridge builds in the western CONUS. While
temperatures in the western states surge, temperatures in this
part of the country will remain near normal for the first half of
the week. In addition, the first several days of the work week
will remain mainly dry despite the passage of a weak frontal
system through the region on Tuesday. Going into the latter
portion of the week, a portion of the ridge out west will break
off and push through the region Wednesday followed by a slight
turn to southwest flow for Thursday. This will allow warmer and
more moist (hence unstable) air into the region in advance of a
more organized frontal system, both at the surface and aloft.
Precipitation chances increase into the chance category for much
of the WFO MPX coverage area for Thursday, which is generally
consensus but also the best chance for precipitation next week
beyond the weekend.


.AVIATION...(For the 18Z TAFS through 18Z Saturday afternoon)
Issued at 1239 PM CDT Fri Jun 16 2017

VFR conditions expected through the period. Scattered showers and
thunderstorms will develop later today, most numerous across
southern MN into western WI. Additional showers and storms will
develop Saturday afternoon.

KMSP...Winds AOB 8 or 9 kts expected through the period, largely
southwest through Saturday, although they could go variable

Sun...VFR. Chc -SHRA. Wind NW 10-15 kts.
Mon/Tue...VFR. Wind NW 5-10 kts.




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