Area Forecast Discussion
Issued by NWS Twin Cities, MN

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FXUS63 KMPX 200419

Area Forecast Discussion
National Weather Service Twin Cities/Chanhassen MN
1119 PM CDT FRI AUG 19 2016

.UPDATED for 06Z Aviation Discussion...
Issued at 1113 PM CDT Fri Aug 19 2016


.SHORT TERM...(This evening through Saturday)
Issued at 402 PM CDT Fri Aug 19 2016

Afternoon water vapor imagery shows a mid/upper trough over the
Dakotas. Weak upglide ahead of this feature continues to instigate
very light and widely scattered showers. Meanwhile, the more
concentrated thunderstorm activity is to the south over Iowa where
instability is higher near the front. Therefore, really do not
expect much this evening in our area other than the continuance of
spotty showers. Higher chances arrive overnight as the trough axis
enters western MN. Have centered the highest precip chances between
06Z and 18Z for MN, and through 21Z for WI counties.

Due to the trough being centered overhead and accompanied by
extensive low cloud cover and precip on Saturday, high temperatures
will likely be the coolest we have experienced since around the 1st
of June, which is around 10 to 15 degrees below normal for this
time of August.

.LONG TERM...(Saturday night through Friday)
Issued at 402 PM CDT Fri Aug 19 2016

The long term will be categorized by a fairly progressive, though
amplified pattern as we begin our transition to a bit more fall-
like weather. A cool weekend for mid August standards is still
expected, with a quick warmup Monday/Tuesday ahead of the next
cold front Tuesday night/Wednesday, with temperatures similar to
what we are expecting this weekend coming to end next week.

Saturday night, we will be slowly working showers out of western
WI as the upper wave currently working across the Dakotas today
slowly moves across the Great Lakes. The NAM and Canadian have
started to come in line with the GFS/ECMWF with a more eastern
track for the heaviest precip Saturday/Saturday night, so we did
start trimming how far west there are mentionable pops Saturday
night, keeping them confined to western WI. Behind this rain,
surface ridge axis and clearing skies moving into western MN means
we should see some folks in west central MN start out in the upper
40s Sunday morning, before we turn into a sunny Sunday with highs
in the 70s.

Monday, we quickly get into return flow and warming temperatures
as southerly winds quickly increase. The models show a 30kt llj
coming up on Monday, with a decent amount of WAA, but little model
derived QPF is generated. 1000-500 RH shows the atmospheric
column is rather dry, but you can`t completely rule out some
thunderstorms over central MN Monday afternoon within this WAA
regime given the increase in elevated instability as well. That
thunder threat will continue into Monday evening, but lift north
with the warm front, with thunderstorm chances for the MPX area
not really increasing until Tuesday evening, which is when the
cold front begins moving into western MN. This front looks to
cross the MPX area Tuesday night into Wednesday afternoon. So
timing isn`t the greatest for seeing the warmest temperatures we
could or getting much in the way of severe weather, though the
20-25 kts of 0-1km shear should be more than adequate for a few
strong to severe storms come Wednesday afternoon ahead of the

The 19.12 ECMWF came in faster with the midweek fropa, becoming
more in line with the GFS. This likely means we are too slow in
clearing the precip out Wednesday night. By Thursday, h85 temps
are back in the single digits, which means we should see highs
back in the 60s and lower 70s.


.AVIATION...(For the 06Z TAFS through 06Z Saturday night)
Issued at 1113 PM CDT Fri Aug 19 2016

There is one area of rain that will affect KEAU tonight, while
another area to the west will move eastward and affect the rest of
the taf sites Saturday morning. Should see some MVFR clouds with
this second batch of rain as northwest winds increase to around 50
kts. The skies will lift to VFR from west to east during the day
on Saturday.

Forecast guidance still shows the potential for sub-1700ft
ceilings on Saturday, but continued with a more optimistic forecast
in the Taf since those lower ceilings have yet to manifest
themselves upstream. Should see some steady light rain Saturday
morning as well.

Sun...VFR. Winds NW at 10G15 kts.
Mon...VFR. Winds SSW at 15G25 kts.
Tue...VFR. Winds SSW at 15G25 kts.


.MPX Watches/Warnings/Advisories...


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