Area Forecast Discussion
Issued by NWS La Crosse, WI

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FXUS63 KARX 230808

Area Forecast Discussion
National Weather Service La Crosse WI
308 AM CDT Sun Oct 23 2016

.SHORT TERM...(Today and tonight)
Issued at 308 AM CDT Sun Oct 23 2016

Short-wave across the central Dakotas as of 23.0730Z per water
vapor imagery will move along the Canadian border and into the
western Great Lakes by this afternoon. At the surface, a cold
front will sweep across the forecast area. Deepest moisture
necessary for precipitation likely to remain across northeast MN
and northern WI, but do expect an increase in afternoon cloud
cover, especially north of I-94. Bigger impact locally will be
breezy northwest wind behind the front with roughly 30 to 40 kts
atop the mixed boundary layer. This will result in frequent gusts
from 25 to 35 mph, strongest in the wind prone areas west of the
MS River. Temperatures today will be dependent on frontal passage,
with highs in the mid to upper 50s across the northwest and in the
mid to upper 60s across portions of northeast IA and southwest WI.

Mostly clear skies and light northerly wind tonight in the post-
frontal air mass will result in nighttime lows in the 30s.

.LONG TERM...(Monday through Saturday)
Issued at 308 AM CDT Sun Oct 23 2016

After a mostly sunny/dry, but cooler day on Monday under the
influence of surface high pressure, rain returns Tuesday and
Wednesday. All ingredients still in place for periods of moderate
to heavy rain showers (especially Tuesday night into Wednesday
morning), including PWATs up to one inch, strong 850 to 700 hPa
frontogenesis and isentropic lift on the 300 K surface. That said,
23.00Z model suite has wavered a bit in its track of the surface
low with the GFS shifting south and the ECMWF shifting north.
While 48 hour QPF from the model consensus and GEFS plumes
suggest 1 to 3 inches are possible, this does introduce some
uncertainty into the placement of highest rainfall amounts. For
now, areas south of I-90 appear to be favored, but will need to
watch model trends over the coming days. Will also continue
isolated thunder mention for areas south of I-90 given the
potential for some MUCAPE in the 200 to 400 J/kg range.

Even with the potential for a few inches of rain, not expecting
much in the way of hydro concerns given forecast rain rates and
rather dry period over the past month with most areas only having
received 25 to 50 percent of their normal rainfall for this

Medium range models are in slightly better agreement Thursday and
beyond, showing northwest flow aloft as a ridge attempts to
reassert itself across the western CONUS. This allows bits of
short-wave energy to bring a couple slight chances for showers
mainly Friday night and Saturday, but dry conditions should
dominate much of the latter half of the week into the weekend.
Temperatures will be seasonable for late October with highs mainly
in the 50s and lows in the mid 30s to 40s.


.AVIATION...(For the 06Z TAFS through 06Z Sunday night)
Issued at 930 PM CDT Sat Oct 22 2016

RAP/HRRR/NAM12 Bufkit soundings all adamant that while the sfc winds
will stay light southeast overnight at KLSE, just off the sfc the
winds will be on the increase. This increase should act to prevent
any fog that develops over the main channel of the Mississippi from
spreading across KLSE - so will continue to keep it vsby restriction
free with just some scattered low cloud.

Cold front sweeps through in the morning, with winds increasing and
shifting to the northwest. GFS/NAM RH fields point to the potential
for mvfr cigs dropping southeast later Sunday afternoon. Going to
keep the trend of VFR for now, but something to be watched.




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