Area Forecast Discussion
Issued by NWS Twin Cities, MN

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FXUS63 KMPX 261813

Area Forecast Discussion
National Weather Service Twin Cities/Chanhassen MN
1213 PM CST Sat Nov 26 2016

.SHORT TERM...(Today and tonight)
Issued at 328 AM CST Sat Nov 26 2016

Main forecast concern deals with areas of dense fog where skies
cleared overnight in the region that had more snow cover.

Since Friday evening, skies slowly cleared across central/east
central Minnesota, and into west central Wisconsin. As skies
cleared, and winds remained light, fog formed, especially from
Litchfield, east to the Twin Cities, and northward into central
Minnesota. High clouds began to filter eastward across Minnesota
after midnight, which limited the spread of the fog west toward west
central Minnesota. In addition, and based on GOES cloud thickness
layer, and visfog satellite trends, the thicker clouds were
spreading northeast into northeast Minnesota, with thinner clouds
and more fog across central Minnesota. This will lead to any fog
this morning to quickly burn off. However, due to the weak boundary
layer wind field and model trends of expanding the cloud cover back
southward later this afternoon/evening, kept temperatures cooler in
this region. Elsewhere, more sunshine and warmer air spreading
eastward, 40s will be common, even a few upper 40s are possible in
south central Minnesota.

Only forecast change tonight is to continue clouds spreading
southward, and the formation of fog once again. Boundary layer winds
are high enough to limit widespread fog from forming.

.LONG TERM...(Sunday through Friday)
Issued at 328 AM CST Sat Nov 26 2016

Model agreement regarding the evolution of a closed low ejecting
from the Rockies to the Upper Midwest during the long term
forecast period continues to improve gradually with each
successive run. Confidence is high that we will see rain across
the forecast area on Sunday evening through Monday as the
associated surface low lifts north from eastern Nebraska/South
Dakota toward North Dakota. Expect most of the forecast area to
see around one half inch of rain or more by Monday evening with
elevated instability parameters still indicative of the potential
for a few claps of thunder.

Monday night into Tuesday looks to be a period when most of the
forecast area will be in the dry slot, until Tuesday afternoon and
night when wrap-around precip moves in as the low lifts to the
Arrowhead. We have the potential to warm up substantially on
Monday afternoon with any amount of clearing given the southerly
flow. Highs in the lower 40s to lower 50s are anticipated. Monday
night the intrusion of colder air aloft will trigger the
introduction of a rain-snow mix, with mainly snow expected Tuesday

Wednesday and Thursday still look to be cloudy with light precip
as we remain in the cyclonic flow on the western fringes of the
departing trough, with dry high pressure gradually working in by
next weekend.

With the influence of the trough mid to late next week, there
will be little diurnal variation in temperatures, with highs in
the 30s and lows in the 20s.


.AVIATION...(For the 18Z TAFS through 18Z Sunday afternoon)
Issued at 1213 PM CST Sat Nov 26 2016

Fog is again the primary forecast concern. Where snowpack is
greatest in central MN, fog has been slow to budge and do not
think this is going anywhere today or tonight. AXN may see the
visibility increase to between 1 and 4 miles this afternoon, but
they will quickly fog back in. Also expect fog to develop again
tonight in western WI where winds will be lightest. There is
potential that fog could develop at RWF/MSP as well given moist
boundary layer and light winds, but will keep the fog mention to
near the snow and lightest winds. Sunday morning will see
increasing southeast winds as the next storm system approaches,
with rain moving into the terminals for the 00z TAF window.

KMSP...Only potential problem will be the treat for fog tonight.
Fog stayed out of MSP last night and expect the same tonight,
with the vis dropping down to 4 or 5 miles. Rain looks to arrive
shortly after 00z Mon, or just beyond the 30 hour window.

Mon...MVFR early with -SHRA. Wind S 10-15 kts.
Tue...MVFR/IFR. Chc -RA. Wind SW 5-10 kts.
Wed...MVFR/IFR. Chc -RA/-SN. Wind NW 5-10 kts.




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