Area Forecast Discussion
Issued by NWS La Crosse, WI

Home | Current Version | Previous Version | Text Only | Print | Product List | Glossary Off
Versions: 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 31 32 33 34 35 36 37 38 39 40 41 42 43

FXUS63 KARX 201736

Area Forecast Discussion
National Weather Service La Crosse WI
1236 PM CDT FRI MAY 20 2016

.SHORT TERM...(Today and tonight)
Issued at 303 AM CDT Fri May 20 2016

Latest water vapor satellite imagery showing upper level closed low
over the pacific northwest and a couple of weak shortwaves along the
international border and over the Central Plain states. Latest
infrared satellite imagery indicating mid to high clouds expanding over
much of Iowa and parts of southeast Minnesota in association with
the shortwave over the Central Plain states.

Main forecast concerns today into tonight are temperatures and
clouds. Shortwave trough over the Central Plain States moves
slowly into the Ohio river valley and will continue to advect mid
to high level moisture mainly over the western and southern half
of the forecast area today. This will result in partly sunny to
mostly cloudy skies over much of the forecast area today. High
temperatures will remain near normal...with temperatures climbing
into the lower to middle 70s.

.LONG TERM...(Saturday through Thursday)
Issued at 303 AM CDT Fri May 20 2016

The 20.00z GFS/NAM are in good agreement with upper level/surface
ridge entrenched over the Upper Midwest and Great Lakes Region
Saturday into Sunday. This will provide dry weather conditions
across the forecast area. Both the 20.00z GFS/NAM filter in warmer
temperatures into the region...with 850mb temperatures rising into
the plus 10 to plus 14 degrees celsius by 00z Monday. High
temperatures are expected to climb upper 70s to lower 80s Saturday
into Sunday.

Focus then turns to Sunday night into Thursday. The 20.00z
GFS/ECMWF/GEM are in decent agreement in lifting the upper level
low over the Pacific Northwest into southern Canada and develop
southwesterly flow aloft over the Rocky Mountains into the
Northern Plains. The main difference between the 20.00z
GFS/ECMWF/GEM is timing of each individual impulse tracking into
the Upper Midwest and Great Lakes Region through the period.
With the southwesterly flow aloft....a more active weather
pattern develops over the forecast area Sunday night into
Thursday due to increasing moisture and lift in association with
each impulse. Next concern is potential for severe thunderstorms
during the period. The 20.00z GFS indicates 0-3km shear of 20 to
30 knots through much of the period. However...deep shear of 0-6km
remains less than 30 knots for much of the period. Due to timing
issues with each impulse and given amount of shear...severe
weather threat is too early to discern at this time.


.AVIATION...(For the 18Z TAFS through 18Z Saturday afternoon)
Issued at 1236 PM CDT Fri May 20 2016

VFR conditions continue through the TAF period as high pressure
just to the west slowly works overhead into midday Saturday.
Diurnally driven cumulus deck (briefly some brief broken ceilings
around KRST) should mostly dissipate with sunset, leaving just
some higher cirrus at times floating through the area overnight.
Winds from the southeast up to 10 knots will become light and
variable tonight into Saturday morning with the ridge axis
centered squarely overhead.


.ARX Watches/Warnings/Advisories...


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