FXUS63 KMPX 190902

Area Forecast Discussion
National Weather Service Twin Cities/Chanhassen MN
402 AM CDT Tue Mar 19 2019

.SHORT TERM...(Today through Wednesday)
Issued at 402 AM CDT Tue Mar 19 2019

A weak surface trough passing over the region today will result in
little more than a southerly wind shift and slight increase in cloud
cover, with another dry and seasonable day expected. Temperatures
will be a few degrees warmer than yesterday thanks to southwesterly
low-level advection, with highs ranging from the upper 30s across
western Minnesota to the mid 40s across southern/eastern Minnesota
and west-central Wisconsin. Overnight, another shortwave pivots out
of western Ontario towards Lake Michigan, and looks to generate
enough forcing for light precipitation across western Wisconsin. A
dusting of snow looks possible north of I-94 across west-central
Wisconsin overnight Tuesday into Wednesday morning with any
precipitation ongoing by late morning changing over to rain. A weak
cold front trailing along this system will pause our Spring warm up
for a day with highs Wednesday looking to remain in the low to mid
40s. Low temperatures today and Wednesday morning will again remain
below freezing which will help to control the rate of snow melt and
runoff into area rivers. Ice jam flooding along smaller rivers and
tributaries along with localized road closures from ponding water in
ditches and culverts still look to be the primary flooding threat,
especially during the afternoon when runoff will be greatest.

.LONG TERM...(Wednesday night through Monday)
Issued at 402 AM CDT Tue Mar 19 2019

Few weather concerns through the extended, with a fairly orderly
snowmelt still anticipated. Best chance for precip is in the Sunday
to Monday timeframe, though if we even see anything, amounts will be
pretty minimal and not really add much to the snowmelt runoff.

Not much has changed in what the models are showing for the large
scale pattern evolution over the next week, with the blocking high
currently over BC/Alberta slowly building east into central NOAM
this weekend. A trough will come out of the southwest and will be
falling apart as it runs into the ridge over the weekend. To end
the period, an upper trough will drop out of northern Canada into
the Great Lakes, which will put us back into northwest flow to start
next week.

The extended will start with a couple of clear days Thursday and
Friday. There will be a cold frontal passage Thursday afternoon
though, with a cool high pressure center arriving for Friday. We've
seen the ECMWF and GFS back off several degrees for highs on Friday
thanks to this cooler high, with highs in the 40s now progged from
both models for Friday.

For the weekend, all of the models bring upper energy over MN in one
way or another by Sunday, but differ on how strong that energy will
be. The GFS continues to be the most bullish with holding this wave
together enough to bring a band of precip (and rain at that) across
the area Saturday night into Sunday. The ECWMF has this wave getting
ripped apart as it moves into the blocking high centered over the
Canadian Prairies, resulting in a dry forecast. Beside this wave
coming up from the southwest, there will be a strong trough rotating
around Hudson Bay on Sunday, which will be sending a cold front down
from Canada. As this front interacts with the remnants of the
southwest trough Sunday night, this may give us our best chance at
seeing precipitation, but with general subsidence aloft, we will see
minimal precip amounts if we see anything at all. We continued to
stick with blended PoPs given the spread, which are really just a
reduced version of what you would get if you went straight GFS given
both the Canadian and the ECMWF are pretty much dry. Finally, only
other change for the weekend is that we are seeing models back off
some on how warm we'll get, with 60s pretty much dropping of the
map with the 19.00 model runs, though highs in the 50s, especially
on Saturday look like a good bet.

As we start next work week, the front coming through Sunday night
will result in a chilly start to the work week, with an airmass
originating over the Canadian arctic progged to drop through here
Mon/Tue, which if this idea holds together, would send highs back
into the 40s.


.AVIATION...(For the 06Z TAFS through 06Z Tuesday night)
Issued at 1050 PM CDT Mon Mar 18 2019

VFR conditions expected through the period with extensive mid
level clouds tonight, scattering out Tuesday. Winds will back
south tonight and then increase and veer more westerly Tuesday.

KMSP...No additional concerns.

WED...VFR. Wind W 10 kts.
THU...VFR. Wind NW 5 kts.
FRI...VFR. Wind S 5 kts.




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