Area Forecast Discussion
Issued by NWS La Crosse, WI

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FXUS63 KARX 272006

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

.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 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

.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 18Z TAFS through 18Z Saturday afternoon)
Issued at 1242 PM CDT Fri May 27 2016

Challenges include timing of showers and lower ceilings/visibility
through the period. Expect two rounds of mainly showers; the first
this afternoon and the second overnight into Saturday morning.
Cannot completely rule out thunder, but not enough confidence to
include in 18Z TAFs. Upstream observations showing widespread MVFR
ceilings and will trend KLSE in this direction by 27.21Z, whereas
KRST ceilings are already below 2000 ft agl and likely to remain
so through the period. Reductions in visibility as low as 2-3 sm
possible in heavier showers. After a break in showers this
evening, some forecast guidance is very pessimistic with potential
IFR conditions overnight. Lower confidence in this scenario, but
something to monitor over the next 6-12 hours. Will bring in
second round of showers by 28.08Z. Winds through the period will
be light (less than 10 kts), generally with an easterly or
southerly component.


.ARX Watches/Warnings/Advisories...


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