Area Forecast Discussion
Issued by NWS La Crosse, WI

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FXUS63 KARX 151126
AFDARX

Area Forecast Discussion
National Weather Service La Crosse WI
626 AM CDT Sun Apr 15 2018

.SHORT TERM...(Today through Tuesday)
Issued at 330 AM CDT Sun Apr 15 2018

Winter storm going to keep snow going for much of today as the
closed 500 mb low/trough churns slowly to the oh river valley by 12z
monday, developing somewhat of a negative tilt as it does. System
still not stacked, with the sfc low eking out toward PA by this
time. Moisture continues to feed into the storm through, rotating
into/around it...helping fuel the deformation region. Various bits
of shortwave energy rotate down the backside of the departing
trough, and some indications of frontogenetic banding on the
north/west side of the low. Could see some banding.

Current radar continues to lift the main (mostly) snow area area
northeast across WI early this morning, with mostly dry slotting
along and west of the Mississippi. Some banding just west of the
there though (western ia/mn). Mesomodels expand snow westward from
the main area over WI this morning, enhancing this area as it comes
under the influence of the leading edge of the upper level wave and
some frontogenetic forcing. RAP is the most aggressive when it comes
to additional snow amounts, suggesting inch per hour rates nearly
all morning for KLSE. NAM/HRRR less, and probably more reasonable.
North of I-90 and esp I-94 will have the best opportunity for
several more inches of accumulation. The bulk of the accumulations
should be done by 00z this evening. I

Wind remains a factor and will have considerable impacts on travel
into tonight. North northeast winds will continue to howl today,
although a bit less than yesterday/last night - sustained 15 to 25
mph with gusts in the mid 30s. Expect blowing/drifting of the
fallen/falling snow, especially in open and unsheltered areas.

For headlines...will extend warning in the north into the evening to
match lingering snow trends. To the west, conditions warrant more of
an adv rather than warning now, so will downgrade. Will keep rest of
the headlines going til 00z.

.LONG TERM...(Wednesday through Saturday)
Issued at 330 AM CDT Sun Apr 15 2018

Seriously...enough with you winter. You had your chance. Let spring
in and take a nap for the summer. MORE winter weather is looking
likely for late Tue night/Wed. The GFS and EC continue to spin an
upper level shortwave trough out of the southern rockies/desert
southwest to across IA/southern WI Tue night through Wed. Pretty
good west-east running frontogenetic response north of system`s sfc
low, with additional lift from the left exit region of a 100kt 300
mb jet streak. Added to this mix with be a nice fetch of low level
moisture transport feeding into and north of the sfc low, with even
a little elevated instability in the GFS to suggest a thunder threat
across the south. Pcpn will result. That said, it could be rain,
snow to a wintry mix. Both the EC and GFS show a decent amount of
low level warming, resulting in a mixed bag of pcpn types. There has
been variability with placement of the low and how much cold/warm
air will be there to incorporate into the pcpn type questions - so
refining the details problematic at this time. But with some
consistency in bringing the shortwave through, a period of pcpn is
looking likely for this time frame...whether it`s rain...snow...or
something in between.

Looking ahead to the upcoming weekend...the GFS and EC continue to
slide an upper level trough from the west coast eastward into the
southern plains, with a slight northeast push into the oh river
valley. GFS quicker than the EC, while both have shifted the system
more south this go around - keeping most of the impacts/pcpn threat
south of the local area. Another system that bears watching.

&&

.AVIATION...(For the 12Z TAFS through 12Z Monday morning)
Issued at 626 AM CDT Sun Apr 15 2018

Accumulating snow will continue across the taf sites today,(very un
mid-April like) with MVFR/IFR cigs/vsbys in the snow. The snow will
diminish late this afternoon and evening as the responsible sfc thru
mid level finally moves far enough away from the region. Around 4
inches of snow is expected at KLSE thru this evening, with 3 to 4
inches at KRST. Vsbys will improve to VFR after 00-01z. However cigs
are expected to remain MVFR thru tonight as moisture stuck in the
broad lower level cyclonic flow over the Upper Midwest continues to
rotate across the area. Winds will generally remain in the 15-25kt
range today/tonight, gradually swinging from NE to N today then to
NW tonight.

&&

.ARX WATCHES/WARNINGS/ADVISORIES...
WI...Winter Weather Advisory until 7 PM CDT this evening for WIZ054-
     055-061.

     Winter Storm Warning until 7 PM CDT this evening for WIZ041>044-
     053.

     Winter Storm Warning until 10 PM CDT this evening for WIZ017-029-
     032>034.

MN...Winter Weather Advisory until 7 PM CDT this evening for MNZ086-
     087-094-095.

     Winter Storm Warning until 7 PM CDT this evening for MNZ088-096.

     Winter Storm Warning until 10 PM CDT this evening for MNZ079.

IA...Winter Weather Advisory until 7 PM CDT this evening for
     IAZ008>011-018-019-029-030.

&&



$$

SHORT TERM...Rieck
LONG TERM....Rieck
AVIATION...Lawrence



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