Area Forecast Discussion
Issued by NWS Twin Cities, MN

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098
FXUS63 KMPX 261747 AAB
AFDMPX

Area Forecast Discussion...UPDATED
National Weather Service Twin Cities/Chanhassen MN
1247 PM CDT MON SEP 26 2016

.SHORT TERM...(Today and tonight)
Issued at 320 CDT Mon Sep 26 2016

Surface analysis this morning shows a deep surface low sitting
over southwestern Ontario province with its main cold front
extending SSE through the Great Lakes region then turning SW over
the lower Mississippi River Valley. There is also a secondary
weaker trailing cold front, mainly associated with the sharp
trough axis aloft swinging through northern MN into NW WI.

Scattered rapid-moving showers pushing through NW MN into WI will
overall move off to the east this morning such that the main
concern for precipitation beyond this morning through tonight, if
anything at all, would be in the far eastern WI counties within
the WFO MPX coverage area. Clouds will also hold on fairly strong
in northern and eastern portions of the coverage area through the
day today, again due to the large trough moving through. Said
trough will expand once the upper low moves into southeastern
Ontario province, keeping its western extent over WI and into
eastern MN. The low looks to stall out and drift slightly to the
south, which would make for some difficulty in eroding the clouds
away and out of the coverage area completely. Nevertheless,
despite ample sun for southern and western areas today and the
clouds holding on in the north and east tonight, strong cold air
advection will overcome the insolation/cloud variances through
tonight. Highs will only range from the upper 50s north and east
(where the more stoic clouds will be) to the mid 60s south and
west (plenty of sun). Lows tonight will be quite cool, dropping to
the low-mid 40s.

The other concern today will be strong NW winds with a tight
pressure gradient developing behind the departing cold front and
incoming high pressure centered over the northern-central
Rockies. Sustained speeds will increase to 20-25 mph with gusts
upwards of around 35 mph. These speeds will commence by late
morning and persist through much of the day, dropping off after
sunset.

.LONG TERM...(Tuesday through Sunday)
Issued at 320 AM CDT Mon Sep 26 2016

The only concern in the extended period is the possibility of
wider coverage of showers Tuesday afternoon as the Upper Low
slowly sagged southward across the Great Lakes.

Models are in much better agreement on the evolution of the Upper
Low developing north of the Great Lakes, and slowly sagging this
feature southward into the Ohio Valley by late in the week. This
will keep cooler conditions to the forecast than previously
advertised, but still not overly cool for this time of year. As
stated before, there could be a wider coverage of the
precipitation Tuesday afternoon if the Upper Low, and deeper
moisture moves further to the west than expected. Current trends
of this scenario has led to isolated showers in east central
Minnesota Tuesday afternoon. Chances will be raised if the current
trends suggest. In addition to the precipitation, temperatures
will also fall in anticipation of cloudy skies and scattered
showers.

Past Wednesday, no major changes to the forecast but the
aforementioned Upper Low will have impacts on temperatures, and
likely continuing the dry forecast into next weekend as this
feature will hold back the Upper Ridge in the west.

&&

.AVIATION...(For the 18Z TAFS through 18Z Tuesday afternoon)
Issued at 1247 PM CDT Mon Sep 26 2016

VFR conditions expected through tonight. Lower cigs, potentially
MVFR levels will slide south across central/eastern MN and western
WI early Tuesday with scattered showers pushing through mid to
late afternoon. Otherwise, gusty west northwest winds will ease
this evening and increase again Tuesday morning.

KMSP...Gusts to 35 kt at times this afternoon. Otherwise, no
major concerns.

/OUTLOOK FOR KMSP/
Wed...VFR. Wind N 5-10 kts.
Thu...VFR. Wind light and variable.
Fri...VFR. Wind SE 5 kts.

&&

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

$$

UPDATE...JPC
SHORT TERM...JPC
LONG TERM...JLT
AVIATION...BORGHOFF



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