Area Forecast Discussion
Issued by NWS Twin Cities, MN

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FXUS63 KMPX 272152

Area Forecast Discussion
National Weather Service Twin Cities/Chanhassen MN
352 PM CST Mon Feb 27 2017

.SHORT TERM...(This evening through Tuesday)
Issued at 350 PM CST Mon Feb 27 2017

Surface analysis shows a pair of low pressure centers, both of
which will have some impact on the weather for the WFO MPX
coverage area during the next 30 hours. One low center is over
north-central SD while the second is over northeast CO. Surface
fronts extend nearly E-W from each low, including one that is
draped over southern MN into western WI this afternoon. Aloft, a
generalized zonal flow from WSW to ENE will prevail across the
region, spelling an overall lack of upper level support for
either front as it interacts with a surge of Pacific moisture
moving across the region. The northernmost front looks to nudge
northward, keeping relatively warmer air across the region tonight
into tomorrow. This will mean most of the coverage area will have
low temperatures at or above freezing. The main exception will be
far northwestern portions of the coverage area - mainly far west-
central MN. As precipitation develops overnight, this part of the
coverage area will be susceptible to a wintry mix of light
snow/sleet/freezing rain. Not looking for much at all in the way
of QPF (only a few hundredths) or coverage. That said, the
potential is there for a very light ice glazing along with up to a
couple inches of snow. Each is just shy of hitting criteria for
any supplemental products so have maintain mention in the
Hazardous Weather Outlook. The remainder of the coverage area will
see a mixture of -RA and -DZ, with -DZ being more likely due to
mid-level dry air being entrained between the frontal system to
the north and the one to the south. In addition, some higher
dewpoint air being advected in atop snowpack to the south may
result in patchy to areas of fog over southern and central
portions of the coverage area. The precipitation will linger
through the first half of the day tomorrow then gradually diminish
going into tomorrow evening as the northern low moves into the
Great Lakes and the southern low moves into eastern IA/northwest

.LONG TERM...(Tuesday night through Monday)
Issued at 350 PM CST Mon Feb 27 2017

After tonights/Tuesday system moves east of our region, the mean
long wave trough will move through the area, which will aid in the
continuation of scattered flurries or light snow from Tuesday
night, and into Wednesday. However, moisture is lacking and upper
level energy is weak. We could get an inch or two, especially in
southwest Minnesota Tuesday night, but nothing to extreme. Another
storm system, moving rapidly to the southeast late Wednesday
night, and into Thursday, is a typical "Alberta Clipper" which
will bring a light dusting on the northeast side of the surface
low. QPF amounts and the relatively weak mid level short wave
associated with this system, should limit snowfall amounts. Maybe
a quick 2-4 inches if the warm air advection regime becomes
stronger than the models appear.

Not too many changes in the extended period, with the coolest air
mass in the next 7 days from Tuesday night, and into Friday. An
upper ridge begins to build across the Upper Midwest by Friday
night/Saturday, leading to temperatures once again rising to above
normal readings for early March. The temperature profile for this
weekend is not extreme, so I don`t anticipate any records.

By late Sunday, and early next week, models diverge on the mean
upper level flow which leads to low confidence on either a warm or
a cooler period/pattern. The EC/GEM are more progressive with a
trough moving across the Upper Midwest, vs. the GFS which is
lagging behind. The GEFS mean 50H flow holds onto the ridge longer
so I did not deviate on temperatures other than the typical


.AVIATION...(For the 18Z TAFS through 18Z Tuesday afternoon)
Issued at 1211 PM CST Mon Feb 27 2017

Surface front will remain over south-central MN into northern WI,
wobbling north-south over the area through the next 24 hours. This
may cause minor but quick wind shifts from time to time but
overall the winds will generally come from the south today then
back to southeast this evening before shifting to north tomorrow.
Speeds throughout will generally be 10 knots or less. Clouds will
steadily lower this evening through tonight as a weak upper level
shortwave disturbance arrives. Light wintry mix of precipitation
will develop in western-central MN overnight and persist into
tomorrow while eastern MN into western WI receives -DZ/-RA. Flight
conds will likely bottom out into IFR levels by daybreak tomorrow
and remain there through much of the day tomorrow.

KMSP...VFR conditions will prevail into the early morning hours
then conditions deteriorate rather quickly during the pre-dawn
hours with mainly -DZ developing along with BR/FG. Ceilings likely
to drop to IFR levels after daybreak tomorrow with visibilities
mainly in MVFR but IFR visibilities not out of the question.
Conditions slowly improve late tomorrow. Winds will slowly back to
S from SSW this afternoon and continue backing to SE overnight.
Winds then expected to go light/variable through the morning push,
which will contribute to the low stratus/fog development, before
going to NE and N by tomorrow afternoon.

WED...MVFR ceilings likely. Winds NW 5-10 kts.
THU...Chc MVFR/-SN. Winds NW 5-10 kts.
FRI...Mainly VFR. Chc MVFR ceilings. Winds S 5-10 kts.




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