Area Forecast Discussion
Issued by NWS La Crosse, WI

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FXUS63 KARX 111740

Area Forecast Discussion
National Weather Service La Crosse WI
1240 PM CDT Sun Mar 11 2018

.SHORT TERM...(Today and tonight)
Issued at 302 AM CST Sun Mar 11 2018

Fairly potent mid-level vorticity maximum evident on GOES-East was
rotating southeast through eastern NE/western Ia early this morning.
Stretching deformation axis north of this feature was producing a
band of light snow across portions of southeast MN and northeast IA.
A call to law enforcement in Mower MN indicated around 1/2 inch has
fallen. Meanwhile, the rest of the area was under a veil of mid/high
level cloud cover. Temperatures across the area as of 1 am were
in the middle 20s to the lower 30s.

For today, that vorticity maximum will continue driving southeast
through northern MO and then into KY. This is expected to drag that
deformation forced light snow southeast out of the area by 9 am or
so, leaving the area under general mid-level cyclonic flow with very
weak high pressure at the surface. Soundings and lower level model
relative humidity field indicate the area will be under mostly
cloudy conditions with highs today in the middle 30s to the lower

A weak cold front pushes through the area this evening/overnight
with a cooling damp lower boundary layer. This will drag lower
clouds through the area. Was thinking of the possibility of some
drizzle but soundings indicate that subsidence through the cloud
layer should prevent the drizzle. Shouldn`t see much in the way of
fog either with gradient winds keeping the lower boundary layer
stirred enough. Otherwise, plan on lows dropping into the 20s.

.LONG TERM...(Monday through Saturday)
Issued at 302 AM CST Sun Mar 11 2018

Northerly flow and shortwave troughs passing through look to make
Monday and Tuesday brisk cool days. Have added some flurries in
central WI Monday night to target one of the more vigorous
shortwaves shifting through. Lapse rates steepen through 2.5 km
and there is a bit of CAPE under the cap which could manifest some
snow showers. Most of the models are dry. Will have to watch that
trend for more SW- activity. This wave quickly moves through and
by Tuesday morning the air mass stabilizes. 15-25 mph winds on
Monday will make it feel like the 20s.

Wednesday through Saturday...
Ridge builds in earnest Wednesday and begins the warm-up into 50s.
There are differences in the end of week details as the longwave
trough evolves over the West. The longwave trough has evolved a
bit more off the coast in the recent model runs, with differences
in the shortwave trough energy ejecting out through the region
Fri/Sat. For now it is just small rain/snow chances as the timing is
difficult. Overall, a more active pattern again late week.


.AVIATION...(For the 18Z TAFS through 18Z Monday afternoon)
Issued at 1240 PM CDT Sun Mar 11 2018

Ceilings have steadily dropped throughout the region this morning
as a large area of stratus continued to move in. VFR ceilings are
expected to drop to MVFR at LSE this afternoon and persist
through tonight, dropping below 2000 ft agl this evening. Could
also see some scattered clouds below 1000 ft. Some guidance does
hint at brief periods of IFR ceilings at LSE, but confidence is
not high enough to include at this time. For RST, a brief period
of MVFR will be seen this afternoon, before upstream IFR ceilings
move in. Ceilings look to improve a bit into low MVFR during the
early morning hours Monday. The question then becomes whether or
not clouds scatter out at one or both TAF sites and if so, when.
Earlier guidance suggested LSE would be just west of the cloud
shield, but latest trends have the clouds farther west, keeping
LSE under a broken MVFR deck. Despite the westward trend, looks
like RST will scatter out by Monday morning, but there are a few
pieces of guidance that suggest broken low MVFR or IFR ceilings
continuing through nearly the end of the TAF period. Otherwise,
winds will become northwesterly and continue to increase into the
7 to 10 kt range, with perhaps some gusts near 20 kts at RST at
the very end of the TAF period. Visibility is expected to remain
P6SM due to these winds.




LONG TERM...Baumgardt
AVIATION...CA is the U.S. government's official web portal to all federal, state and local government web resources and services.