Area Forecast Discussion
Issued by NWS Twin Cities, MN

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FXUS63 KMPX 300519
AFDMPX

Area Forecast Discussion
National Weather Service Twin Cities/Chanhassen MN
1219 AM CDT TUE AUG 30 2016

.SHORT TERM...(This evening through Tuesday)
Issued at 305 PM CDT Mon Aug 29 2016

Surface analysis shows a cold front extending from northwestern MN
across eastern SD early this afternoon, along with an outflow
boundary over south central MN from earlier convection. Surface
dewpoints locally in the warm sector ahead of the main front are in
the upper 60s to lower 70s, with plenty of sunshine breaking out to
aid destabilization. Mid level lapse rates around 7-7.5C will
combine with the increasing MLCAPES to spark thunderstorm
development in the vicinity of the front. The only limiting factor
is shear, which is not impressive. Therefore the threat for severe
weather remains limited but not out of the question. Given the slow
storm motion heavy rainfall will be a concern as well, and will have
to monitor the threat for a Non-supercell tornado or two over south
central MN in the vicinity of the outflow boundary.

In the wake of the convection late tonight winds are fairly weak and
we may see enough clearing to result in fog development with the
moist ground conditions.

Tuesday should bring continual clearing, with mostly sunny skies by
mid to late afternoon. Highs will still be a bit above normal, and
range in the upper 70s to around 80.

.LONG TERM...(Tuesday night through Monday)
Issued at 305 PM CDT Mon Aug 29 2016

The longer term concern remains the dry trend through the rest of
the work week...and timing of next trough and surface front into
next weekend.

Cool and dry high pressure will move across the region during the
week. The coolest day appears to be Thursday...with slow moderation
thereafter as upper heights rise/ridging and southerly surface
flow develops. The GFS and ECMWF have similar timing in passage of
the front on Labor Day. The GFS ensemble mean is a little slower
but the trough associated with this system appears to be quite
strong. Forcing will be directed favorably along the front for at
least the possibility of heavy rain. Filtered CWASP is pointing
toward a severe weather threat as well...as several of those
parameters are looking favorable for Monday.

&&

.AVIATION...(For the 06Z TAFS through 06Z Tuesday night)
Issued at 1219 AM CDT Tue Aug 30 2016

TSRA sinking slowly southward early this morning through the Twin
Cities, KRNH and KEAU. This activity is well ahead of a cold front
that was located over central MN between KAXN and KSTC at
midnight. Two concerns for early this morning, first is that the
convection is back building to the west and may impact KRWF in the
07z to 09z time frame while the TSRA from the Twin Cities on east
continues to sink slowly south and weaken early this morning.

The second concern overnight is the threat for dense fog with
VLIFR conditions. Much of this will depend on how fast clouds
dissipate early this morning, if at all. The site where
confidence is highest is KSTC where over 4 inches of rain fell
this evening. KRWF...KRNH and KEAU may also see these low
conditions if clouds dissipate.

KMSP...+TSRA until 07z then SHRA through 08z with the rain
expected to be over for the rest of the night. A cold front
across central MN will pass the airfield around 12z with north
winds less than 10 knots through the day on Tuesday.

/OUTLOOK FOR KMSP/
WED...VFR. Wind NNE 5 kts.
THU...VFR. Wind E 5 kts.
FRI...VFR. Wind SSE 7-10 kts.

&&

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

$$

SHORT TERM...LS
LONG TERM...DWE
AVIATION...RAH



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