Area Forecast Discussion
Issued by NWS La Crosse, WI

Home | Current Version | Previous Version | Graphics & Text | 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 44

FXUS63 KARX 292055

Area Forecast Discussion
National Weather Service La Crosse WI
255 PM CST Tue Nov 29 2016

.SHORT TERM...(This evening through Wednesday)
Issued at 255 PM CST Tue Nov 29 2016

Main forecast concerns are on rain and snow showers on Wednesday
with the potential for some very light snow accumulation mainly on
grass surfaces.

Low pressure continues to spin across the Upper Midwest late this
afternoon and will start edging eastward into the local area late
tonight through Wednesday. The cloud cover forecast will be
challenging tonight across the southeast 1/2 of the forecast area.
Clouds across portions of northeast Iowa, southeast Minnesota, and
central Wisconsin will edge southeast leading to cloudy skies
across most if not all of the area. However, this may not happen
until Wednesday as the the low moves in. Light rain and snow is
possible tonight mainly west of the Mississippi River as the first
wave of vorticity moves through. Periods of light rain and snow
showers are expected on Wednesday, especially late morning into
the afternoon when low level lapse rates will be the steepest.
Minor snow accumulations are possible and under the steadier snow
showers we could pick up a trace to perhaps a few tenths
accumulation before quickly melting. Also, the snow showers may
produce some brief visibility restrictions at times.

.LONG TERM...(Wednesday night through Tuesday)
Issued at 255 PM CST Tue Nov 29 2016

The low continues to edge east Wednesday night but we will stay in
cyclonic flow providing cloudy skies and perhaps some very light
rain or snow. Rain/snow chances linger into Thursday morning then
weak surface high pressure edges into the Upper Mississippi River
Valley. We should finally start to break out of the pesky low
clouds by late in the day Friday as the cyclonic flow aloft
finally shifts east. Cooler temperatures are on the way for
Thursday into Friday. Friday looks to be the cooler of these two
days when highs will struggle to get out of the 30s.

The 29.12Z GFS and ECMWF have come into better agreement on the
synoptic pattern through the weekend, but timing differences still
exist. Both models bring two shortwaves through the region. The
first one early Saturday is weaker and slightly out of phase between
the models. The second one is stronger and passes through on Sunday.
Moisture and forcing are not that impressive, especially with the
first wave. The ECMWF is a little more excited with spreading QPF
across our area on Sunday with the second wave. The GFS and ECMWF
bring ridging through late Sunday into Monday ahead of a shortwave
progged to move from Texas towards the Great Lakes and a deepening
longwave trough over the western CONUS. The GFS is slightly quicker
bringing the Texas shortwave towards our region late Monday. Both
models contain good forcing and moisture signals for precipitation
from this system, which could be a wintry mix.


.AVIATION...(For the 18Z TAFS through 18Z Wednesday afternoon)
Issued at 1124 AM CST Tue Nov 29 2016

A bank of stratus continues to impact the terminal sites, but with
ceilings rising back to VFR levels the next hour or two at LSE but
likely holding at MVFR for RST into this evening. An approaching
upper wave and deeper moisture should bring back lower ceilings to
all sites late tonight through Wednesday, with IFR conditions
likely for both sites as some light rain and snow makes an
appearance, especially during the late morning and beyond. There
is some risk for light accumulation at RST after the current TAF




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