Area Forecast Discussion
Issued by NWS Twin Cities, MN

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604
FXUS63 KMPX 240842
AFDMPX

Area Forecast Discussion
National Weather Service Twin Cities/Chanhassen MN
342 AM CDT WED AUG 24 2016

.SHORT TERM...(Today and tonight)
Issued at 342 AM CDT Wed Aug 24 2016

Early this morning, the center of the surface low was north of Lake
of The Woods along the border of Manitoba and Ontario.
A cold front extending southward through western MN was advancing
eastward with time.  Showers and thunderstorms overnight were fading
away as they move through western Wisconsin.

The main focus of the short term is the passing cold front which
will move through the Twin Cities late morning and clear Eau Claire
late this afternoon.  The drop in dew points will lag about an hour
or two behind the wind shift.  Dew points in the mid to upper 60s
ahead of the front will fall about 10 degrees within about 2-3 hours
of the front passage.  Plenty of low level dry air with this
boundary today so not expecting any precip to form along it, and if
any does it would be very isolated.  In terms of wind speeds today,
the pressure gradient isn`t real strong behind this front as the
surface low has a modest 1005mb central pressure.  Expect northwest
winds around 10-15 MPH across the area this afternoon.  The deep
cold air advection won`t really arrive until tomorrow so daytime
highs will still have 850mb temps around +15C to work with and with
mixing heights behind the front of near 850mb, highs should top out
around 80 degrees today.  All of this will lead to a quiet night
with temperatures falling into the upper 50s (low 60s in the metro)
under partly cloudy skies.

.LONG TERM...(Thursday through Tuesday)
Issued at 342 AM CDT Wed Aug 24 2016

Concerns in the long term focus on precipitation chances this
weekend with diminishing pops early next week.

Some very pleasant weather conditions will cover the forecast area
on Thursday as high pressure builds in. Surface dew points will
be in the upper 40s to lower 50s along with afternoon highs in
the upper 60s to lower 70s. Rural areas will likely see low
temperatures dip into the middle and upper 40s Thursday night as
the high passes by.

Rain chances will be on the increase for Friday night and
Saturday as a deepening upper level trough pushes across the
Northern Plains. Low level moisture transport will increase
quickly by Saturday with PWAT values progged to reach 1.5 inches
across southern MN. This is above the 90th percentile for late
August. Various long term model solutions indicate an area of
vorticity riding northeast from the desert southwest on Friday and
passing across southern MN on Saturday. If this feature ends up
occurring, it will certainly aid in enhancing the rainfall across
southern MN on Saturday with heavy rainfall along with some
flooding possible. August is certainly turning into a wet month
for portions of the FA with MSP now nearly double the normal
rainfall through the 23rd. Much of the MN River Valley has seen
150 to 200 percent of normal precipitation over the past 90 days.
The forecast of likely pops for much of the area on Saturday looks
good with the likely pops expanded a little to the west with a
slowing seen with the upper trough.

This wave will be over the region on Sunday with high chance pops
still in place. Height rises will take hold for Sunday night and
Monday as the wave pushes east along with an area of high
pressure moving across the Upper Mississippi Valley. Blended pop
guidance insisted on 15-20 pops (slgt chc) for both of these
periods. We trimmed the pops to below 15 percent for much of the
region to eliminate the slight chance. If the GFS trends slower
and more like the EC, then the dry pattern could be extended
through Tuesday.

&&

.AVIATION...(For the 06Z TAFS through 06Z Wednesday night)
Issued at 1129 PM CDT Tue Aug 23 2016

Widespread showers and thunderstorms are ongoing across southern
MN and are gradually moving east into WI. KAXN and KSTC are in the
clear for now and will probably stay that way tonight. For the
rest of the night, MVFR conditions with rain and embedded
thunderstorms will be the story. Clouds gradually clear in the
morning as the rain moves east. MVFR will transition to large
areas of IFR as low clouds spread in behind the rain.

KMSP...
Scattered showers will hang around for at least the first half of
the night - most of it will remain across southern MN, but still
close enough to include in the forecast. MFR ceilings, possibly
even IFR possible, for the morning commute.

/OUTLOOK FOR KMSP/
Wed nite...VFR Wind nw 5-7 kts.
Thu...VFR. Wind NW 7-10 kts.
Fri...VFR. Wind SSW 5-10 kts.

&&

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

$$

SHORT TERM...SPD
LONG TERM...RAH
AVIATION...CLF



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