Area Forecast Discussion
Issued by NWS Twin Cities, MN

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426
FXUS63 KMPX 230339
AFDMPX

Area Forecast Discussion
National Weather Service Twin Cities/Chanhassen MN
1039 PM CDT MON AUG 22 2016

.UPDATE...For 06z Aviation discussion below

&&

.SHORT TERM...(This evening through Tuesday)
Issued at 300 PM CDT Mon Aug 22 2016

Dry weather expected for the next 24 hours, but an area of showers
and thunderstorms will move up from the southwest Tuesday afternoon
ahead of an upper level wave. Early morning water vapor imagery
together with GFS 500 mb heights and winds identified the trough
across the OK/TX panhandle. This wave will lift northeast, and
forecast models are in good agreement with showers and thunderstorms
develop across the NE/IA border shortly after 18Z, and these storms
will move into southern MN Tuesday afternoon.

The highest threat for severe weather will be near initiation across
NE/IA, but there is a marginal risk for storms across Minnesota and
Wisconsin. Forecast soundings show around 1500 to 2000 J/kg of CAPE,
but the wind profile is very unorganized with a veered/backed
pattern, so there should a very limited ceiling on the extent of
severe weather.

.LONG TERM...(Tuesday night through Monday)
Issued at 300 PM CDT Mon Aug 22 2016

The extended period will remain progressive for the next 7 to 10
days.

The best chance of widespread precipitation occurs from Tuesday`s
night, through Wednesday morning. Due to the progressive nature
and a strong west-southwest flow aloft, I would not be surprised
to see the precipitation end by sunrise Wednesday for most of MPX
forecast area. The only area of concern or lingering showers will
occur in west central Wisconsin where wrap around moisture and
instability showers/storms may occur as the system intensities
across the Great Lakes region.

As discuss earlier with the progressive nature of the extended
period, the next chance of precipitation may occur quicker Friday
then what models indicate. Based on current trends, most of Friday
should be dry with the exception in western Minnesota by the
afternoon. Usually as the low level jet kicks in, the best chance
of precipitation will occur Friday night. Depending upon the how
outflow boundaries interact with the instability over the weekend,
chances of showers and thunderstorms will continue. Timing and
placement remains questionable. It will also turn warmer and more
humid by Saturday/Sunday. The driest day in the next 7 will occur
on Thursday with temperatures will be 5 to 10 degrees below
normal.

The mean upper level flow continues from the west-southwest next
week along with embedded short waves diving southeast across the
Rockies and into the Northern Plains. One weather element that
remains favorable is near or slightly below normal temperatures
along with wetter than normal conditions. There are also no signs
of a big heat wave for the next 10-14 days.

&&

.AVIATION...(For the 06Z TAFS through 06Z Tuesday night)
Issued at 1042 PM CDT Mon Aug 22 2016

VFR conditions are expected into Tuesday evening...and then
showers and thunderstorms are expected to spread north and east
from SD/IA across the area Tuesday night into Wednesday.
The main focus this TAF period remains on wind. Gusts will
continue to slowly subside late this evening, and then the main
concern becomes low level wind shear. Still expect to see 2000ft
winds around 45-50kts developing between 06-08z...from a 210-230
directional component. Surface gusts return around 15z Tuesday,
with sustained 15-20kt speeds gusting into the mid/upper 20s
(knots). Mostly sunny conditions are expected on Tuesday, but
mid/high clouds will be on the increase toward the evening as
convection develops over IA/SD. Have included a Prob30 for SHRA/TS
after 03z at KRWF and 09z at KMSP.

KMSP...
Low level wind shear looks to be developing at the start of the
period, persisting until around or shortly after 14z when surface
gusts return. The threat for thunder looks to return
overnight...primarily after 09z Wed.

/OUTLOOK FOR KMSP/
Wed...VFR with -TSRA/MVFR possible. Wind SW 5-10 kts becoming W.
Thu...VFR. Wind NW 7-10 kts.
Fri...VFR. Wind SSW 5-10 kts.

&&

.MPX Watches/Warnings/Advisories...
WI...None.
MN...None.
&&

$$

SHORT TERM...JRB
LONG TERM...JLT
AVIATION...LS



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