Area Forecast Discussion
Issued by NWS La Crosse, WI

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FXUS63 KARX 261845

Area Forecast Discussion
National Weather Service La Crosse WI
145 PM CDT Wed Apr 26 2017

.SHORT TERM...(Tonight through Thursday Night)
Issued at 145 PM CDT Wed Apr 26 2017

Major pattern change underway as an area of deep low pressure
continues to track northeast through WI. Temperatures as of 1 pm
this afternoon ranged from the upper 30s across southeast MN to the
lower 60s across central WI. Current radar showed bulk of
precipitation associated with this low pushed into northeast WI.
Otherwise...abundant stratus and areas of drizzle noted across the
forecast area with winds picking up out of the northwest. These
northwest winds were ushering in very chilly air into the region
with readings across MN in the 20 and 30s.

For tonight, look for chillier air to continue filtering into the
area as the surface low pulls toward Upper MI. Models bring in
another surge of moisture after midnight, but looks like the bulk of
this resulting rain will be over southwest into eastern WI.
Elsewhere, across our area, model soundings show a lot of lingering
stratus over us with lift under cyclonic low-mid level flow. As
temperatures fall into the lower 30s from southeast MN into north
central WI, there could be some light icing from the drizzle on
elevated/exposed objects such as trees and wires.

Chance of drizzle lingers into Thursday morning before moving off to
the northeast in the afternoon. Otherwise, skies will remain mostly
cloudy across the area with colder cyclonic flow continuing. As a
result, look for highs only in the 40s. Brisk west/northwest winds
of 10-20 mph, gusting to 25 mph will also add a bite to the chilly

Clearing looks to take place across the majority of the area
Thursday night as the low pulls farther northeast into Canada and
highs pressure builds in from the Northern Plains. Slackening winds
combined with the clearing and colder air for areas of frost as
temperatures fall into the 30s, even some upper 20s across the
sand country of Central WI. Frost/freeze headlines may be needed.

.LONG TERM...(Friday through Wednesday)
Issued at 145 PM CDT Wed Apr 26 2017

Mostly wet/colder than normal weather on tap for the period.

For Friday into Friday evening, a wave of low pressure slides just
south of the forecast area across northern IL. This will likely push
some light rain into areas south of I-90. Otherwise, look for mostly
cloudy skies with highs in the upper 40s to the middle 50s.

The majority of the area looks dry for Saturday with the exception
of portions of northeast IA into far southwest WI ahead of
strengthening low pressure moving north out of the Southern Plains.
Look for highs in the 50s.

A strong storm system lifts north out of the Southern Plains toward
the area. This system looks to have a strong trowal signature
associated with it that rotates into our area during the day Sunday.
Copious gulf moisture will be available with this system with
precipitable water values increasing into the 1-1.5 inch range. So,
could see some heavier rainfall as this system moves into the region
Sunday. Will have to keep an eye on this as antecedent ground
conditions are quite moist and susceptible to runoff. Both the 12z
GFS/ECMWF show the surface/mid-level low becoming stacked as they
move northeast across WI Sunday night through Monday, keeping
deformation snow northwest of the area with mainly a cold rain
continuing across the area. Plan on chilly highs Sunday and Monday
mainly in the 40s.

Models have the low pulling north of the area Monday night/Tuesday
dragging the bulk of precipitation with it. Will likely see isolated
to scattered showers continuing though given colder/cyclonic flow
aloft. Look for highs Tuesday in the 50s.

A chance of showers will continue Wednesday as a mid-level trough
rotates southeast out of the Northern Plains. Otherwise, looks a bit
more mild with highs in the middle 50s to near 60.


.AVIATION...(For the 18Z TAFS through 18Z Thursday morning)
Issued at 1213 PM CDT Wed Apr 26 2017

Low stratus and patchy drizzle will plague the taf sites thru this
afternoon and tonight as low level moisture remains trapped in and
under a strengthening inversion and under sfc-mid level cyclonic
flow. Cigs thru tonight are expected to remain IFR and lower MVFR as
a seasonably cold airmass spreads in. Drier sfc/boundary layer air
and NW winds 10-15kts will generally keep vsbys in the P6SM range
thru tonight. Some improvement in the cigs expected during the mid-
late morning hours Thu as the sfc-805mb low lifts NE of the area and
the sfc-850mb flow becomes more westerly and pulls in drier low
level air from the Plains.




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