Area Forecast Discussion
Issued by NWS La Crosse, WI

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FXUS63 KARX 051853

Area Forecast Discussion
National Weather Service La Crosse WI
1253 PM CST Tue Dec 5 2017

.SHORT TERM...(Tonight through Wednesday)
Issued at 1253 PM CST Tue Dec 5 2017

Abrupt switch to winter is manifesting itself in form of strong west
winds, sharply colder temperatures, low clouds, and intermittent
flurries or snow showers as area resides in northwest flow behind
slowly exiting cyclone.

Still experiencing some wind gusts above 40 mph this afternoon as
pressure gradient remains tight across the region. Some relaxing
expected heading into tonight but decrease will be gradual. Wind
advisory will be allowed to drop off but it will still remain windy
well into tomorrow.

Main focus is cloud trends and then snow chances for Wednesday.
Cyclonic flow has led to more development today than previously
expected but some of this should clear out this evening as slightly
drier wedge of air drifts in from the west. Clouds may hang tough
the further northeast you go though.

Models in good agreement trending higher moisture back southward on
Wednesday, and with weak lift noted in lower levels, could likely
see expansion of clouds lead to more flurries or snow showers.
Southward extent of clouds and flurries still in question but this
element certainly increased in forecast.

Welcome to winter.

.LONG TERM...(Wednesday Night through Tuesday)
Issued at 1253 PM CST Tue Dec 5 2017

Looking an awful lot like winter the next 10 days, with maybe a
brief reprieve to the coldest temperatures sometime toward the
weekend. As much-discussed over the past few days, the overall
pattern across North America will remain dominated by pronounced
western ridging as well as ridging into Greenland, effectively
draining the coldest air from Canada southward into much of the
central and eastern CONUS into at least the middle portion of next
week (some hints this pattern will remain locked the next 2-3
weeks). That setup will tend to keep us near to below normal in the
temperature department, with various reinforcing rounds of colder
air being introduced by a myriad of shortwaves dropping through the
mean overall trough centered over the Great Lakes. Starting to see a
little more run-to-run consistency among guidance for the timing of
said waves through late week, with the next of interest arriving
Wednesday evening and night and another on its heels toward Friday
and Friday night.

The leading wave later Wednesday doesn`t have much in the way of
moisture, though with all of the cloud deck bisecting the dendritic
growth region, have few doubts we`ll see widespread flurries or even
a little light snow for many areas. With that said, still looking
for a stronger wave to arrive Friday into Friday night with
increasing consensus many areas will pick up a little light snow
accumulation, though likely with limited impacts given the expected
"fluffy" nature of any snow. Thereafter, still looking like we may
see a brief retreat of the coldest air later in the weekend but with
another reinforcing shot arriving early next week (timing still
somewhat uncertain). Overall, a very typical winter-time pattern
across the area - colder weather fans rejoice!


.AVIATION...(For the 18Z TAFS through 18Z Wednesday afternoon)
Issued at 1138 AM CST Tue Dec 5 2017

Cold, cyclonic flow will prove tricky with ceilings, winds, and
occasional snow into Wednesday. Seeing more cloud development
upstream with MVFR ceilings but they will be in-out at times with
brief reductions in visibility due to snow showers. Winds also
remain strong, out of the west, and gusts in the 30 to 40 kt range.

Short term models still hint at some airmass drying except closer to
Interstate 94 so banking on a VFR period tonight before cyclonic
flow drives low clouds back into area on Wednesday. With that could
see more snow flurries and widespread MVFR conditions. Detail will
need to be added later but introduced more clouds and occasional
snow threat.


WI...Wind Advisory until 6 PM CST this evening for WIZ054-055-061.

IA...Wind Advisory until 6 PM CST this evening for IAZ008>011-018-019-



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