Area Forecast Discussion
Issued by NWS Twin Cities, MN

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FXUS63 KMPX 191147

Area Forecast Discussion
National Weather Service Twin Cities/Chanhassen MN
647 AM CDT THU MAY 19 2016

.SHORT TERM...(Today and tonight)
Issued at 436 AM CDT Thu May 19 2016

Southerly winds will increase slightly today as high pressure over
the Great Lakes slides east.  As a result expect to see an increase
in low level moisture and cloudiness. Temperatures aloft are
cool enough that we will see some slight instability that will
lead to a few stray showers mainly across the west and northern
areas of the forecast area. Any showers will be done by sunset as
they are driven by afternoon heating. Another nice day temperature
wise with temperatures similar to Wednesday or near normal. A few
clouds will linger overnight with low temperatures slightly

.LONG TERM...(Friday through Wednesday)
Issued at 436 AM CDT Thu May 19 2016

The forecast remains split down the middle...with the first half
being dry and the second half having a much better chance for
showers and thunderstorms. The main focus for storms will be late
Sunday into Monday as a cold front moves through the region. However
unsettled weather will continue into the middle of next week with
southwest flow setting the stage for MCSs across the Midwest. It
remain uncertain where these thunderstorm complexes will track.

On Friday and upper level shortwave will dive south across the
region, so continued with a 15 to 20 percent pop along the Minnesota
River Valley. Saturday will be dry...and Sunday is trending that way
as well. Sunday night into Monday an upper level wave will drive a
cold front through the region. From roughly 700mb and up this is a
favorable setup for severe weather, with 7 to 8 C/km mid level lapse
rates and 50kts as 500mb. However, the high amplitude flow leads to
a large area of subsidence downstream with cool dry air over the
Great Lakes region. The southeasterly flow on the back side if this
surface High is feeding into the "warm sector" ahead of this cold
front, but the reality is this warm sector could be nothing more
than T/Td of 75/55. This will not provide the thermodynamic piece of
the puzzle, and as a result the severe weather risk is low.

Once again, if dewpoints manage to pool ahead of the front into the
lower 60s, and if the diabatic heating manages to produce surface
temps in the upper 70s, then we could have enough instability for a
few strong to severe storms on Monday. Looking ahead, there will be
a brief dry period after this front passes, but southwest flow will
remain in place and should see nocturnal MCSs form over the Midwest.
At this time the most likely scenario is to see these storms across
IA, but continued with 20 to 30 percent chance pops for MN/WI.


.AVIATION...(For the 12Z TAFS through 12Z Friday morning)
Issued at 647 am CDT Thu May 19 2016

Some high level and a few mid level clouds made an appearance
overnight while winds became southerly. Low level moisture will
move into the area today and as a result we will see an increase
in clouds especially in the north and west. There may even be a
few stray showers over the same area...not enough confidence that
one Will find a terminal, hence no mention of vcsh in any of the
TAF sites. Ceilings will be scattered overnight. friday will be
similar in terms of cloud coverage and a very isolated shower. not expect any precipitation and ceiling may take longer
to come in this afternoon. No additional issues.


SAT...VFR. Wind SE 5-10 kts.
SUN...VFR. Wind S 5-15 kts.
MON...VFR. Wind S 10-20 kts. Scattered thunder showers.


.MPX Watches/Warnings/Advisories...


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