Area Forecast Discussion
Issued by NWS Twin Cities, MN

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FXUS63 KMPX 140929

Area Forecast Discussion
National Weather Service Twin Cities/Chanhassen MN
429 AM CDT Fri Jul 14 2017

.SHORT TERM...(Today and tonight)
Issued at 412 AM CDT Fri Jul 14 2017

The short term concern is clearing trend today and resultant high
temperatures. Then any convective risk over far northern cwa late

The latest fog satellite product indicates some bkn-ovc stratocu
over much of the cwa. Some clearing beginning to the far north.
Once it does clear temepratures drop off into the lower 50s
quickly with the threat of some fog. The clearing should continue
slowly to the south and east this morning as the high pressure
ridge moves east. Sunshine is expected for much of the afternoon.
This should help temepratures warm through the 70s to the east,
with some lower 80s to the far west.

Later tonight, some high clouds will move into the northwest cwa
ahead of the incoming cold front. Convection is expected to be
limited with this feature as mid level capping develops. Most
HIRES models are not showing any real development along this
boundary overnight. The deterministic models do try and develop
some light QPF associated with there mainly isolated convection.
We will hold onto the slight chance PoP over the far northern cwa
late tonight for now.

.LONG TERM...(Saturday through Thursday)
Issued at 412 AM CDT Fri Jul 14 2017

Much of the extended portion will be dominated by surface high
pressure, meaning infrequent periods for precipitation. However,
there will be two main frontal systems pushing through the region:
one on Friday night through Saturday and another late Monday
through Tuesday.

The first system will follow high pressure departing the area and
will bring a noticeable increase in both warm air and moisture.
Ridging from 850mb-700mb will allow temperatures to climb to
around 90 degrees on Saturday while dewpoints rise through the 60s
into the lower 70s. This will allow for heightened instability but
the disjointed nature of the system features will make for meager
storm initiation. The main area for storms look to be in far
eastern MN into western WI Saturday afternoon and evening, and
will be mainly driven by how much influence a nearby upper level
trough can contribute to the surface features and deep moisture.
There is even the potential for severe thunderstorms given the
strong instability and ramped up bulk shear but there is also
plenty of uncertainty in timing/placement at this time.

The second system will come after high pressure regains control
over the area for Sunday and Monday. Another surge of warm air
and moisture from the deep south will develop in advance of a
Pacific-origin system that will interact with another shortwave
trough disturbance dropping in from central Canada. This system
will be a little more organized than the weekend system and a
little more prolonged, hence several periods of PoPs in the
forecast. High pressure will then become the prevailing feature
for the latter half of the week.


.AVIATION...(For the 00Z TAFS through 00Z Friday evening)
Issued at 854 PM CDT Thu Jul 13 2017

Thinking remains similar to earlier, with current low VFR and
marginal MVFR ceilings being the main concern. Still look to stick
around most sites into tomorrow morning, although will certainly
need to monitor trends with some amendments likely, particularly
for the western sites.

KMSP...Main uncertainties are how long ceilings will stick around,
and whether we will see them dip into the MVFR range. Kept things
around until mid-morning Friday, with a flirtation of 3000 ft AGL
for much of that time. Wouldn`t be shocked if things scatter out a
bit earlier or later, and will need to keep an eye on trends
through the night.


Saturday...Brief MVFR possible in the afternoon with a slight
chance of a thunderstorm, otherwise VFR. Southwest wind 5 to 10
Saturday night...Brief MVFR possible in the evening with a slight
chance of a thunderstorm, otherwise VFR. Southwest wind 5 kt or
less shifting northeast around 10 kt.
Sunday...VFR. Northeast wind 5 to 10 kt becoming east.
Sunday night...VFR. Southeast wind 5 to 15 kt.
Monday...MVFR possible early, otherwise VFR. Southeast wind 5 to
15 kt becoming south 10 to 20 kt.




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