Area Forecast Discussion
Issued by NWS Twin Cities, MN

Home | Current Version | Previous Version | Text Only | Print | Product List | Glossary Off
Versions: 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 31 32 33 34 35 36 37 38 39 40 41 42 43 44 45 46 47 48 49 50

FXUS63 KMPX 261140

Area Forecast Discussion
National Weather Service Twin Cities/Chanhassen MN
640 AM CDT MON SEP 26 2016

Issued at 630 AM CDT Mon Sep 26 2016

Updated to include 12z aviation discussion below.


.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

.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

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 12Z TAFS through 12Z Tuesday morning)
Issued at 630 AM CDT Mon Sep 26 2016

VFR throughout this TAF set. Upper level trough swinging through
northern MN and northern WI will spread midlvl clouds into central
MN and WI later today. Main sites to be impacted look to be KSTC-
KMSP and the WI TAF sites while KAXN-KRWF should remain cloud-free
today. Decks look to be no lower than 5 kft. Skies will clear out
tonight over MN but clouds will still linger at KRNH-KEAU
overnight into Tuesday morning. Winds will become strong by late
morning as sustained winds increase to around 20 kt and gusts hit
around 30 kt. Directions will generally remain between 270-300.

KMSP...Breezy northwest winds will be the main issue. Sustained
speeds will increase to near 20 kts by late morning and remain
breezy through the afternoon, diminishing to around 10 kts after
sunset. Confidence is high that directions will remain 270-300

Wed...VFR. Wind N 5-10 kts.
Thu...VFR. Wind light and variable.
Fri...VFR. Wind SE 5 kts.


.MPX Watches/Warnings/Advisories...


AVIATION...JPC is the U.S. government's official web portal to all federal, state and local government web resources and services.