Area Forecast Discussion
Issued by NWS Twin Cities, MN

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FXUS63 KMPX 260901

Area Forecast Discussion
National Weather Service Twin Cities/Chanhassen MN
401 AM CDT Wed Jul 26 2017

.SHORT TERM...(Today and tonight)
Issued at 401 AM CDT Wed Jul 26 2017

Clusters of showers and thunderstorms continue early this morning
in a continued very warm and moist airmass within a corridor of
pwats around 2 inches stretching from southwest MN to northwest
Wisconsin. This corridor of deep moisture will sag south gradually
this morning with high pressure building into the northern
Plains. The best forcing will be confined to areas well to the
south associated with the LLJ currently over southeast Nebraska.
This LLJ will shift eastward today, facilitating training activity
and torrential rain totals south of I-80. There is little forcing
in our area that will provide focus for more organized activity
through the day, so expect continued periods of showers and
embedded thunderstorms across south central MN into west central
WI at least during the morning hours.

Clearing skies will follow the front with much drier air arriving
by this evening. Clear skies and light winds tonight could allow
for some fog formation with crossover temperatures being exceeded
by several degrees. There may be a bit too much wind aloft for
widespread fog, however.

.LONG TERM...(Thursday through Tuesday)
Issued at 401 AM CDT Wed Jul 26 2017

No changes from the previous forecast other than to taper off pops
with the forecast trending drier and drier for the weekend and into
early next week. No significant weather is expected in the form of
severe storms, heavy rain, or extreme heat. The GFS tries to keep a
boundary in place a cross the region and develop convection, but the
ECMWF is much drier and feel that scenario will play out in the
extended part of the forecast.

Northwest flow will develop over the central Conus. Friday and
Saturday look outstanding for those that like sunny skies, light
winds, lower humidity, and highs in the lower 80s. On Sunday a
weakening frontal boundary will move across the Dakotas and moisture
will pool along it leading to a few hundred to a thousand J/kg of
MUCAPE. There is not much forcing with this front, so not expecting
widespread convection, but there is still about a 20 percent chance
of seeing some precip an any particular location.

Looking ahead, as mentioned above the GFS lifts this boundary back
northward and keeps chances for showers and thunderstorms across
much of the area for next week. Can`t rule out the GFS, but at this
time prefer the drier solution of the ECMWF.


.AVIATION...(For the 06Z TAFS through 06Z Wednesday night)
Issued at 1110 PM CDT Tue Jul 25 2017

Main aviation concern is redevelopment of TSRA in the next 6
hours across southern Minnesota, and into west central Wisconsin
as a small area of enhanced instability continues to sag southward
along a front. Confidence is high on redevelopment of storms, but
coverage and location remains low through the overnight hours.
Although I can`t rule out a complex of storms developing across
southwest Minnesota in the next couple hours, based current trends
of the weakening MCS in southeast South Dakota, will only include
VCTS, with the best chance of widespread and IFR conditions near
KMKT. Otherwise, a general decrease in the overall coverage of
TSRA/SHRA is expected after 12z, with only far southern Minnesota
having any chance of TSRA during the afternoon.


Kept a good chance of +SHRA and VCTS between 10-13z this morning.
Confidence is high on redevelopment of storms, but coverage and
location remains low through the overnight hours. Otherwise,
expect a decrease in activity during the morning, with VFR by the
afternoon. Light south/southwest wind early will become
north/northwest toward morning as a front moves through the area.


Thu...VFR. Wind NE 5-10 kts.
Fri...VFR. Wind E 5 kts.
Sat...VFR. Wind S 5 kts.




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