Area Forecast Discussion
Issued by NWS La Crosse, WI

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FXUS63 KARX 280448
AFDARX

Area Forecast Discussion
National Weather Service La Crosse WI
1148 PM CDT FRI MAY 27 2016

.UPDATE...
Issued at 730 PM CDT Fri May 27 2016

Scattered showers and isolated thunderstorms are starting to taper
off this evening as CAPE is starting to diminish. Expect this trend
to continue this evening. With a moist airmass, light winds, and
some breaks in the cloud cover, we may see areas of fog develop
tonight before more showers and storms move in late in the night
into early Saturday morning. We are keeping a close eye on a weak
boundary sitting across western Wisconsin into eastern Iowa.
Storms near this boundary have showed some very weak rotation in
the lower levels. The Non Supercell Tornado Parameter is showing a
weak signal along this boundary too. This concern should quickly
diminish as we lose CAPE. The nearly stationary cells just south
of Clayton and Grant counties have the potential to interact with
this boundary...so will be monitoring this area closely over the
next hour.

&&

.SHORT TERM...(Tonight through Saturday Night)
Issued at 306 PM CDT FRI MAY 27 2016

Radar showing scattered showers/isolated thunderstorms across the
forecast area in broad area of 850mb moisture transport ahead of a
mid-level trough and surface low moving northeast out of the Plains.
Otherwise...skies were mostly cloudy with temperatures ranging from
the upper 60s to the middle 70s.

For tonight...may see a lull in the action this evening but then
expecting a resurgence of showers/isolated thunderstorms later
tonight into Saturday morning. This is in association with lift
ahead of a weak mid-level trough rotating northeastward out of the
Central Plains. Not expecting anything severe with 0-3km MUCAPE
generally less then 500J/kg and 0-3km bulk shear of 15-20kt.

Plan on scattered showers/isolated thunderstorms through Saturday
morning...with increasing thunder coverage during the afternoon in
daytime heating and approach of surface low from IA into southeast
MN. Cannot rule out a few stronger pulse-type thunderstorms with
small hail and wind gusts around 30 mph later in the afternoon with
heating/increasing CAPE into the 1000-1600J/kg range. However...not
expecting anything severe right now as bulk shear lacking for any
decent storm organization. Otherwise...look for highs Saturday...
under mostly cloudy skies...in the middle 70s to near 80.

Mid-level trough/surface low moves overhead Saturday night. General
convergent/cyclonic flow with cooler air aloft is expected to
continue likelihood of showers/isolated thunderstorms through the
night.

.LONG TERM...(Sunday through Friday)
Issued at 306 PM CDT FRI MAY 27 2016

Look for the low to move slowly east with shower/thunder chances
gradually diminishing Sunday afternoon from west to east. Plan on
highs in the middle 70s to near 80. Weak ridging then for Sunday
night with clearing skies.

Shower/thunderstorm chances return on Memorial Day as both the
GFS/ECMWF models showing a weak trough topping mid-level ridge
overhead. NAM contains rain chances west of the area with stronger
ridging. Will maintain a 20-40 probability for now.

GFS/ECMWF continue to show a mid-level trough moving slowly across
the Plains and into the Upper Mississippi River Valley Tuesday
through Friday. This will keep showers/thunderstorms in the forecast
through the week.

Otherwise/temperature-wise...slightly higher than normal readings
will be seen Monday through Tuesday...then cooling to near normal
Wednesday through Friday as the trough moves into the region. Normal
highs for next week are in the 70s.

&&

.AVIATION...(For the 06Z TAFS through 06Z Saturday night)
Issued at 1148 PM CDT Fri May 27 2016

Periods of IFR to MVFR conditions are expected at the TAF sites
through the overnight hours. Plan on visibilities being reduced
into the 1 to 4 mile range with ceilings lowering to around 500 ft
at times. Showers and perhaps isolated thunderstorms will move in
very early Saturday morning then we should see a short break by
mid to late morning with conditions improving to VFR. More showers
and storms are possible by Saturday afternoon then this activity
should taper off Saturday evening.

&&

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

$$

UPDATE...WETENKAMP
SHORT TERM...DAS
LONG TERM...DAS
AVIATION...WETENKAMP



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