Area Forecast Discussion
Issued by NWS Twin Cities, MN

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FXUS63 KMPX 151721

Area Forecast Discussion
National Weather Service Twin Cities/Chanhassen MN
1221 PM CDT Thu Mar 15 2018

Issued at 1215 PM CDT Thu Mar 15 2018

Updated for 18Z aviation discussion below.


.SHORT TERM...(Today and tonight)
Issued at 245 AM CDT Thu Mar 15 2018

Surface analysis early this morning shows a dry cold front
dropping through central MN and northern WI with Canadian high
pressure following it southward. Meanwhile, a potent area of low
pressure is developing over the lee of the Rockies over WY/CO.
Aloft, a sharp ridge axis resides over central NOAM with deep
longwave troughs over the eastern and western NOAM coasts. As the
day progresses, the center of the high pressure area will slide to
the MN international border while the potent low pressure system
develops further over western CO/eastern KS. The surface low will
slide slowly eastward into central KS this evening through
overnight tonight while the area of high pressure over MN/WI also
slowly slides eastward. The high and its ridge axis aloft will
keep the low pressure system well to the south of the WFO MPX
coverage area and also keep any precipitation away from the area
through daybreak Friday morning. As such, aside from passing high
clouds through the day today and a slight increase in clouds late
tonight, mainly over southwestern MN, the only effects of the
synoptic scale systems will be slightly cooler temperatures as
compared to yesterday. Highs today will mainly range 35-40
followed by lows tonight 10-20 degrees.

.LONG TERM...(Friday through Wednesday)
Issued at 245 AM CDT Thu Mar 15 2018

Main concern in the long term remains chance for freezing rain and
snow over far south central MN, mainly along the I90 corridor
Friday into Friday night. Then timing of the next snow threat
arriving next Monday/Tuesday time frame.

Models on converging on the possibility of a wintry mix of light
freezing rain and light snow over far southern Minnesota
developing Friday and continuing into Friday night. At the moment,
the greatest chance of accumulating precipitation is along the
I90 corridor Friday afternoon/night. Any ice accumulation will
likely be limited on roads with temperatures warming into the mid
or upper 30s Friday afternoon. Any snow accumulation should be an
inch or less as well. Low confidence on overall ice accumulation
for the event so a headline is not anticipated. This could change
if more ice lifts into the area early in the period.

Clouds will likely linger to the west into Saturday. Warmer air,
building upper ridging, is expected to move in over the weekend
however, with temperatures expected to warm through the 40s on

Timing of the next weather system remains in question with the
deterministic ECMWF slower with the incoming trough/energy.
Blended guidance looks reasonable taking into account the slightly
faster GFS. Will leave these PoPs go for now with the greatest
coverage moving in for Tuesday across most of the cwa(except far
easter area of west central WI). Cooler than normal temperatures
are expected following the system but warming again by the end of
next week.


.AVIATION...(For the 18Z TAFS through 18Z Friday afternoon)
Issued at 1215 PM CDT Thu Mar 15 2018

Northeast winds have proven stronger than anticipated. Sustained
speeds of 10 knots with some occasional gustiness of 15 to 20
knots expected this afternoon. Clear skies to continue through the
period, VFR throughout. Winds will begin near 030 for direction
and slowly become easterly by tomorrow morning. Winds decrease
near sunset but pick up again tomorrow morning. additional concerns.

SAT...Mainly VFR. Psbl MVFR ceilings. Wind E 5 kts becoming S.
SUN...VFR. Wind variable 5 kts or less.
MON...MVFR and light precip psbl.  Wind ENE 10 kts.




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