Area Forecast Discussion
Issued by NWS Twin Cities, MN

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FXUS63 KMPX 151802
AFDMPX

Area Forecast Discussion
National Weather Service Twin Cities/Chanhassen MN
102 PM CDT Sun Apr 15 2018

.Updated for 18Z Aviation Discussion...
Issued at 1250 PM CDT Sun Apr 15 2018

&&

.SHORT TERM...(Today and tonight)
Issued at 430 AM CDT Sun Apr 15 2018

The main concern in the short term headlines and overall snow
trends through this evening.

The historic winter storm will wind done today. Impressive snow
totals already with a large swath of 10 to 16 inches of snow
across southwest into east central Minnesota.

Overall trend of upper low has been slower movement on all
deterministic models. This will continue the threat of snow,
mainly light across most of Minnesota and bit heavier over
western Wisconsin. Still have decent isentropic lift across
western Wisconsin and forcing remains over that region of the CWA
until this evening. We continued a Winter Storm Warning that area
until 10 PM. Additional snow accumulation of 5 to 9 inches likely
here today. In Minnesota, light snows are expected with a general
2 to 5 inch accumulation expected. Pressure gradient does remain
strong enough for some wind gusts to 30 mph or so across Minnesota
during the day and will continue to cause some blowing/drifting
issues. The Blizzard Warning was transitioned to a Winter Weather
Advisory for Today, as the northerly wind and snow will be
lighter.

This weather system exits the area tonight. Winds will diminish
and partial clearing is expected to the west. Lows tonight will
drop through the upper teens west and the lower 20s to the east,
where clouds should remain.

.LONG TERM...(Monday through Saturday)
Issued at 430 AM CDT Sun Apr 15 2018

Monday-Tuesday...Surface high pressure along with a sharp ridge
axis aloft will slowly shift across the region Monday morning
through Tuesday afternoon. This will promote clearing skies along
with warmer temperatures across the region. Despite ample sunshine
Monday and Tuesday, cooler-than-guidance temperatures can be
expected due to the deep and extensive snow cover across the
region. In addition, the mostly clear skies with light winds
Monday night will promote lows from the mid-teens to the lower
20s.

Tuesday Night-Wednesday Night...While the ridge axis slides
across the area to start the week, a deep longwave trough will
move onshore the western CONUS. This trough will help spawn a low
pressure center over eastern MT/WY and this low is forecast to
track eastward to central IA by Wednesday morning. With the low
remaining generally to the south, which will also prevent ample
warm air advection from reaching up into the Mid-Mississippi River
Valley, the Pacific moisture being brought along with this system
will take the form of mainly wintry precipitation for mainly late
Tuesday night through Wednesday morning. Accumulating snow, along
with the potential for freezing rain, is looking more likely with
this system. Too early to determine specific amounts but there is
growing likelihood of seeing around 4" of additional snowfall
south of the I-94 corridor. The precipitation then looks to change
over to rain Wednesday afternoon before possibly returning to
light snow prior to ending Wednesday night.

Thursday-Saturday...Surface high pressure with ridging aloft again
looks to prevail for Thursday through Friday with warming
temperatures. However, there is still much uncertainty for next
weekend as there is still the possibility of another well-
organized mid-latitude cyclone which could impact the central
Plains through the mid-to-upper Mississippi River Valley region.
Too many variables at play and too much model disagreement to say
whether this could produce additional winter weather or produce
thunderstorms (or both) but this system certainly bears watching
as the week progresses.

&&

.AVIATION...(For the 18Z TAFS through 18Z Monday afternoon)
Issued at 1250 PM CDT Sun Apr 15 2018

MVFR/IFR conditions through the evening as snow showers move
across the region. The heaviest snow will be at KSTC KMSP KRNH and
KEAU. Northeast winds will continue today, but gradually shift to
become northwesterly on Monday. Forecast soundings show low
stratus, so have MVFR cigs for most locations except the western
sites through the duration of the TAF.

KMSP...
There should be another band of heavy snow developing this
afternoon. Visbys in Wisconsin are at 1/2 mile, so could see the
same at KMSP with snowfall rates of 3/4 in per hour possible.
Fortunately the mid April sun will keep the snowfall amounts lower
on clean paved surfaces. The heaviest snow will end around 00Z
this evening, but light snow showers

/OUTLOOK FOR KMSP/
Tue...Mainly VFR. MVFR ceilings possible late. Wind E 5-10 kts.
Wed...MVFR conditions likely in -RA/-SN. Wind NE 5-10 kts becoming
NW.
Thu...MVFR with IFR possible. Wind NW at 10 kts

&&

.MPX WATCHES/WARNINGS/ADVISORIES...
WI...Winter Storm Warning until 10 PM CDT this evening for WIZ014>016-
     023>028.

MN...Winter Weather Advisory until 10 PM CDT this evening for MNZ043-
     044-049>051-059>063-068>070-076>078.

     Winter Storm Warning until 10 PM CDT this evening for MNZ045-052-
     053.

     Winter Weather Advisory until 7 PM CDT this evening for
     MNZ054>058-064>067-073>075-082>085-091>093.

&&

$$

SHORT TERM...DWE
LONG TERM...JPC
AVIATION...JRB



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