Area Forecast Discussion
Issued by NWS La Crosse, WI

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FXUS63 KARX 281720

Area Forecast Discussion
National Weather Service La Crosse WI
1220 PM CDT Wed Sep 28 2016

.SHORT TERM...(Today through Thursday Night)
Issued at 326 AM CDT Wed Sep 28 2016

Water vapor satellite imagery/RAP 500mb analysis shows a closed low
centered near Green Bay WI. Spoke of pv-advection that produced
scattered showers across the area through the evening hours
currently slipping southeast along the WI/IL border with ample low
cloud in its wake across our area. Temperatures as of 2 am were in
the upper 40s to the lower 50s.

The closed low will sink south toward Indiana today with deep/cool
cyclonic flow continuing across our region. Model soundings showing
steepening lapse rates with daytime heating. This is expected to pop
a few showers/sprinkles. Otherwise...another cooler than normal day
on tap with highs topping off in the lower 60s.

Closed low continues to sink southward into the Ohio River Valley
Thursday into Thursday night which will allow default ridging across
our region for clearing skies. Plan on highs Thursday in the 65-70
degree range with lows Thursday night 45-50.

.LONG TERM...(Friday through Tuesday)
Issued at 326 AM CDT Wed Sep 28 2016

Latest GFS/ECMWF in good agreement on lifting the closed low back
north into the lower MI through the weekend, bringing with it
cyclonic flow and threat for showers/sprinkles back into our
region...especially on Saturday.

Looks like a brief nice break Monday as a ridge of high pressure
drifts across the area. Plan on highs in the middle 60s to the lower

Eastern fringe of 850mb moisture transport/isentropic lift ahead of
Northern Plains low pressure will bring a chance of showers and
thunderstorms into the area. Otherwise, looks a tad warmer with
highs in the upper 60s to the lower 70s.


.AVIATION...(For the 18Z TAFS through 18Z Thursday afternoon)
Issued at 1220 PM CDT Wed Sep 28 2016

MVFR/VFR clouds decks will continue to rise thru the afternoon with
diurnal warming and influx of some drier low level air. The diurnal
warming/mixing will result in steeper low level lapse rates this
afternoon, with isolate to sct -shra across the area thru about 23z.
Clouds then expected to decrease/clear thru the early/mid evening
hours with some stronger low/mid level subsidence and a drier 925-
700mb airmass rotating from the northeast. Next concern then
overnight into early Thu morning is radiational valley BR/FG
formation under what would be clear/mostly clear skies, light winds
and the moist boundary layer. However, winds just above the boundary
(around 500 ft agl) expected to be NE in the 15-20kt range which is
not favorable for widespread radiational valley/low laying area
BR/FG. Limited mention in KLSE TAF to BCFG in the 10-13Z time period
as there may some BR/FG hugging the bluffs around sunrise Thu. Other
than that, Thu looking to be good VFR area-wide under clear/mostly
clear skies.




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