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Area forecast discussion...updated 
National Weather Service Twin Cities/Chanhassen Minnesota
1200 am CDT Friday Aug 29 2014

Short term...(this evening through friday)
issued at 258 PM CDT Thursday Aug 28 2014

Early afternoon water vapor imagery shows the middle level trough
lifting northeast from the Central Plains...while surface analysis
shows the related surface low over south central South Dakota. So
far the associated precipitation ahead of this system has been quite
modest...with the leading frontogensis and pv advection rather
meager and lifting out in pieces. has to go south
well into Iowa closer to the warm front before finding any hint of
thunder. Have therefore removed the mention of thunder...and
expect more of a light precipitation/drizzle situation with stratus
clouds to better describe this evenings least until
around/after 06z Friday when the models indicate higher
reflectivity values will nose into southern Minnesota and west
central Wisconsin as the warm front lifts toward the area.

Friday looks to be a fairly wet day for at least the eastern two
thirds of the forecast area...with the middle level trough overhead
and the warm front lifting into southern Minnesota. Have included likely
probability of precipitation /60-70 percent/ along/east of the Interstate 35
corridor...with chance probability of precipitation /30-50 percent/ to the west.

Long term...(friday night through thursday)
issued at 258 PM CDT Thursday Aug 28 2014

Rain will be moving out at the beginning of the period as the upper
level culprit shifts east. Our attention then turns to a potent
cold front and associated trough moving in from the pacnw. This
system will be fairly dynamic as it is aided by the northern
branch of the jet while drawing up some Gulf moisture. -Shra and
embedded ts will be moving across the Dakotas late Sat...while Minnesota
gets juiced up ahead of the front (in terms increasing ll
moisture). Only adding to the thunderstorm set-up will be 40-50kt of bulk
shear (0-6km) and a couple thousand joules of cape by Sun afternoon.
Storm Prediction Center is highlighting our region for the potential for severe weather in
their day 4 outlook...and besides that heavy rain will also be a
potential threat through the afternoon/evening hours on sun. Frontal boundary
will clear the area on Monday with zonal flow in its wake. Typically
this means temperatures near normal with chances of precipitation not entirely
out of the question...but no specific periods of rain to be
highlighted either.


Aviation...(for the 06z tafs through 06z Friday night)
issued at 1155 PM CDT Thursday Aug 28 2014

IFR or LIFR conditions will persist through the overnight and into
at least middle morning Friday...with the worst conditions across
southern and western Minnesota. Models show a somewhat rapid
improvement by late morning...but am a bit skeptical given the
ample low level moisture in place. Will need to watch trends
overnight. Scattered showers will also continue tonight...becoming
a bit more widespread across eastern Minnesota and western WI Friday afternoon.

Kmsp...ceilings have had a hard time maintaining IFR status this
evening...but surrounding observation continue to deteriorate and believe
it won't be too much longer that msp will finally join the IFR
club. Improvements are currently forecast by late morning...but as
alluded to above this may be a bit too optimistic.

/Outlook for kmsp/
Sat...VFR. Wind north-northeast at 5-10 kts.
Sun...VFR with MVFR/thunderstorms and rain late. Winds south-southeast at 10kts.
Monday...VFR with MVFR/thunderstorms and rain early. Winds west 10-15kts.


Mpx watches/warnings/advisories...


long term...jca

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