Area Forecast Discussion
Issued by NWS La Crosse, WI

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FXUS63 KARX 250804
AFDARX

Area Forecast Discussion
National Weather Service La Crosse WI
300 AM CDT THU AUG 25 2016

.SHORT TERM...(Today and Tonight)
Issued at 300 AM CDT Thu Aug 25 2016

Short term concerns are minimal today except for on-going river
flooding. Quiet weather next few days should help with flood clean
up and recovery.

Still tracking upper wave or low that is moving across southern
Manitoba. Current trajectory is southeast but as wave opens up it
should progress east as short term guidance suggests. Either way
lower surface dew points have worked into area behind slow moving
front.

Outside of some mid and high level clouds from convection to the
south, it should remain quiet today with mix of clouds and sun.
Cooler temperatures on tap.

As surface high moves in for tonight, mostly clear skies and light
winds may aid in valley fog formation, even with drier air regime.
Not expecting widespread issues but more typical valley or bog
formation to some degree. Also lowered minimum temperatures in usual
bog areas of Wisconsin.

.LONG TERM...(Friday through Wednesday)
Issued at 300 AM CDT Thu Aug 25 2016

By Friday upper troughing starts to take place to the west as next
wave drops into slowly amplifying flow. While Friday itself should
remain quiet will have to watch for modest moisture return aided by
low level response and lift ahead of approaching wave across
northern tier states. This could spread rain into the area Friday
evening. Some suggestion in 25.00z guidance of quicker return and
have adjusted the forecast database to reflect this.

In assessing any severe weather therat for Friday night or Saturday
main question is amount of instability in quick returning flow.
Again guidance is fairly consistent with better CAPE values
remaining just south and east of the area. Even with some hints in
models that Precipitable Water approaches 1.5 inches, lack of deeper
instability may limit convection that would lead to heavier
rainfall. All in all this bears watching.

Good news the rain threat should push out of the area after
Saturday. Zonal flow restablishes itself with less predictability in
details. Upper ridge may even build in west of region towards mid
part of next week for gradual warmup.

&&

.AVIATION...(For the 06Z TAFS through 06Z Thursday night)
Issued at 1142 PM CDT Wed Aug 24 2016

The cold front has passed well east of the TAF sites now, with
drier air working across the region as high pressure approaches.
That setup will deliver VFR conditions through 06Z tonight for
LSE/RST, with likely a little valley fog for the typical deeper
river valleys but none expected for LSE with stronger flow just
above the surface and continued overnight drying in place. Winds
may get a little gusty from the west into the afternoon hours,
diminshing quickly toward sunset. Will likely see a better risk
for some fog at LSE toward 12Z Friday with high pressure and
lighter winds overhead.

&&

.HYDROLOGY...
Issued at 300 AM CDT Thu Aug 25 2016

Still have moderate to major flooding on many northeast Iowa rivers.
Main problem areas are in the Upper Iowa and Turkey River basins
where warnings continue. Some high water also in Kickapoo River
basin in southwest Wisconsin but that is improving.

Should see most locations crest or fall today with couple of dry
days on tap. Will need to watch rainfall going into weekend. Current
precipitation forecasts would imply about 0.5 to 1.0 inches across
forecast area.

&&

.ARX Watches/Warnings/Advisories...
WI...None.
MN...None.
IA...None.
&&

$$

SHORT TERM...Shea
LONG TERM...Shea
AVIATION...Lawrence
HYDROLOGY...Shea



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