Area Forecast Discussion
Issued by NWS Twin Cities, MN

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451
FXUS63 KMPX 282038
AFDMPX

Area Forecast Discussion
National Weather Service Twin Cities/Chanhassen MN
338 PM CDT SUN AUG 28 2016

.SHORT TERM...(This evening through Monday)
Issued at 339 PM CDT Sun Aug 28 2016

Surface warm front extending into west central MN will continue
lifting north as a cold front approaches from the eastern Dakotas.
Warm air/moisture advection will ensue across northwest and
north central MN tonight as the nocturnal low level jet
strengthens. Showers and thunderstorms are expected to develop in
response over northwest MN, and track east and slightly southeast
overnight. This activity should primarily affect the far northern
part of the forecast area late tonight, and pivot into west
central MN around daybreak Monday. As the front enters the
forecast area during peak heating Monday, expect more widespread
activity to spread east/southeast across the forecast area on
Monday afternoon and evening. Prior to the frontal passage, highs
will warm into the low/mid 80s.

.LONG TERM...(Monday night through Sunday)
Issued at 339 PM CDT Sun Aug 28 2016

The longer term concerns are timing of frontal passage across the
cwa into Tuesday afternoon and the attendant severe weather threat.

Initially the front sags into the northern cwa around 00z Tuesday.
Instability and mid level lapse rates are quite unstable along the
frontal boundary.  The flow is rather weak and deeper shear is lagging
the front.  It appears the greatest threat/high pops will be over the
northeast portion of the cwa into Monday evening. The severe
weather threat looks marginal at the moment...but hail and strong
winds will be a definite threat at least through the evening. If
the front is slower than progged...we could see a heavy rain
threat develop if convection becomes well established. PW`s
increase to about 1.75 inches which is above the 90% percentile
for the date. We will have to monitor this threat into he evening.

The front exits the area Tuesday and a large dry ridge of high pressure
settles over the Great Lakes region through the week.  This should provide
drier dewpoint air with cool nights and steadily warmer days through the
end of the week.  The deterministic models are in fair agreement of bringing
in the next front later Saturday through Sunday. Forecast PW`s increase
out ahead of the western conus trough and should surge out along the front
then...providing another heavy rain threat to the area.

&&

.AVIATION...(For the 18Z TAFS through 18Z Monday afternoon)
Issued at 1250 PM CDT Sun Aug 28 2016

Now that showers and thunderstorms have ended across central MN,
expect dry conditions at sites until possibly overnight
(at KAXN/STC). The broken/overcast deck with sub-1000ft ceilings
will gradually scatter out this afternoon, but sct-bkn clouds
circa 2000-3000ft will persist. Should see enough clearing this
evening to bring a threat for another night with fog development,
although winds will be a tad stronger so widespread dense fog is
not expected. Will need to keep a close eye on WI sites (KRNH and
KEAU) where the potential for LIFR or even VLIFR vsbys is not out
of the question.

Thunderstorms are expected to develop over northwest MN tonight,
then drift east and possibly southeast overnight. There is still
uncertainty regarding how far south these will track. Have
included a Prob30 at KAXN and KSTC for the 08z-12z time frame for
now. A front will pass across the area on Monday, so another
round of showers and thunderstorms will be possible on Monday
afternoon/eve. South/southeast winds will prevail through the
period, with gusts possible during the afternoon time frames.

KMSP...
Sct-bkn borderline VFR clouds (2500-3000ft) will linger this
afternoon. Should see enough clearing tonight to bring the threat
for fog at least in the vicinity of the field. If that occurs,
will also have the potential for IFR CIGS/VSBYS. Shower and
thunderstorm threat with the frontal passage Monday should hold
off until closer to 00z Tuesday.

/OUTLOOK FOR KMSP/
MON EVE...VFR. Chc -TSRA. Wind S 5-10 kts.
TUE...VFR. Wind N 5-10 kts.
WED...VFR. Wind NNE 5 kts.
THU...VFR. Wind SSE 5-10 kts.

&&

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

$$

SHORT TERM...LS
LONG TERM...DWE
AVIATION...LS



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