Area Forecast Discussion
Issued by NWS Twin Cities, MN

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835
FXUS63 KMPX 260923
AFDMPX

Area Forecast Discussion
National Weather Service Twin Cities/Chanhassen MN
423 AM CDT Wed Apr 26 2017

.SHORT TERM...(Today and tonight)
Issued at 422 AM CDT Wed Apr 26 2017

The short term concerns are P-type and temperatures the next 24
hours.

Latest radar showing large area of stratiform rain lifting north
across the cwa. Model trend`s indicate the widespread rain should
lift north into central MN through about 17z. We are seeing
temepratures cooling to around freezing in the northwest cwa
already. Further north adjacent areas reporting a mix of freezing
rain...sleet and some snow. Road temperatures from IEM freeze is
showing temepratures close to freezing in the northwest cwa as well.
A call to Todd county indicated no problems with freezing. We may
see temperatures drop another degree or two and this could generate
some freezing rain in Douglas, Todd and Morrison county this
morning. After collaboration with adjacent offices...we decided to
issue a winter weather advisory for those counties this morning.
Believe any issue on road surfaces will be relieved by mid/late
morning with radiation through clouds as the sun rises and
temperatures remaining around freezing. We may see this eventually
change over to snow with minor accums into the day as cooling
aloft continues.

Tonight...the upper wave lifts northeast and moves through the area.
Any remaining precipitation will likely be in the form of
drizzle/light snow or freezing drizzle. Model soundings do look
rather dry providing little ice for significant snow development.
Temperatures are expected to cool through the upper 20s west and the
lower 30s to the east.


.LONG TERM...(Thursday through Tuesday)
Issued at 422 AM CDT Wed Apr 26 2017

The long term will begin with a surface low pressure system moving
northward across the western Great Lakes. Our far eastern CWA
will still have some light wintry precipitation Thursday morning
before drying commences by afternoon. In the wake of this system,
surface high pressure will nose in from the Dakotas for Friday and
Saturday. This high will be accompanied with surface dew points
in the 20s, manly clear skies and light winds. This will result in
freeze conditions across the FA. Fortunately agricultural
concerns are still pretty minimal but anyone that has put plants
out will need to take action.

Beyond Saturday, the forecast becomes quite interesting as a storm
system moves northward from the Middle Mississippi Valley Region.
The depth and track of the system is similar between the various
deterministic solutions but the timing is not. The GFS is the
fastest with the ECMWF the slowest. It`s interesting to note that
the Canadian H5 low backed from southern WI to IA over the past 12
hours and is similar to the ECMWF. Also, the GEFS position of the
H5 low is in IA as well when the GFS deterministic H5 low is in
WI. This has large implications on the forecast for Sunday through
Monday as cold air works into much of the MN FA with rain
changing to snow.

The GFS would have things about 12 hours quicker with the snow
Sunday night and early Monday while the ECMWF would be more on
Monday. If the slower ECMWF ends up being correct, then our FB
grids are 180 degrees out of whack in the horizontal with regards
to both temperatures and probability of precipitation. Hopefully
future runs will lessen the timing spread and we can get a better
handle on the snowfall forecast. The GEFS plumes point to nearly a
50 percent chance of greater than 3 inches of accumulation to the
west and north to the Twin Cities late Sunday night and Monday
morning. This goes along well with the CIPS Analogs in which 9 out
of the 15 analogs have several inches of accumulation, mainly to
the west and north of the Twin Cities. However, the number one
analog, 19850331, has greater than 6 inches right across the Twin
Cities. It will be interesting to see how we begin May on Monday.

&&

.AVIATION...(For the 06Z TAFS through 06Z Wednesday night)
Issued at 1059 PM CDT Tue Apr 25 2017

Sites will continue to experience intermittent rain through the
overnight hours, with ceilings continuing to degrade to IFR.
Wednesday morning the activity tapers off, but IFR cigs are
expected through Wednesday afternoon, with some improvement to
MVFR possible late in the period. Visibilities should primarily
range from 3SM-5SM in the rain. Northeast winds become more
north/northwesterly on Wednesday with gusts to between 20 and 25
knots common.

KMSP...
Intermittent rain overnight with MVFR visibilities and IFR
ceilings. Winds will gradually increase from the northeast, with
gusts developing by 11z. Rain showers become isolated Wednesday
morning, but the IFR cigs will persist through the afternoon.

/OUTLOOK FOR KMSP/
Thu...MVFR likely, IFR possible. Chc -RA/-SN early.
Winds N 5-15 kt bcmg light & variable.
Fri...Mainly VFR. Winds N 5-10 kt.
Sat...Mainly VFR. Winds NE 5-10 kt.

&&

.MPX WATCHES/WARNINGS/ADVISORIES...
WI...None.
MN...Winter Weather Advisory until noon CDT today for MNZ041>043.

&&

$$

SHORT TERM...DWE
LONG TERM...RAH
AVIATION...LS



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