Area Forecast Discussion
Issued by NWS La Crosse, WI

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FXUS63 KARX 150440

Area Forecast Discussion
National Weather Service La Crosse WI
1140 PM CDT Wed Mar 14 2018

.SHORT TERM...(This evening through Thursday)
Issued at 215 PM CDT Wed Mar 14 2018

At 1 PM, high pressure was providing sunny skies across the Upper
Mississippi River Valley. Where there was little snow cover,
temperatures had warmed into the mid 40s.  Elsewhere, temperatures
ranged from the mid 30s to lower 40s.

High pressure will keep skies mainly clear through Thursday morning.
The one exception will be along and north of Interstate 94 where the
clouds currently over western Ontario may pivot across these areas
during the overnight.  Low temperatures tonight will range from the
teens to mid 20s.

On Thursday afternoon, some mid and high clouds will move into
southeast Minnesota and northeast Iowa during the afternoon.  These
clouds are associated with some moisture spilling over top of the
500 mb ridge. With 925 mb temperatures running about 1.5C colder
than this afternoon, the high temperatures will be about 5F colder
than today.

.LONG TERM...(Thursday night through Wednesday)
Issued at 215 PM CDT Wed Mar 14 2018

Dry high pressure centered from southern Ontario towards Lake
Superior will provide quiet weather into Friday ahead of an upper
level trough that will de-amplify as it approaches the Upper
Mississippi Valley later Friday into Saturday. There remains some
uncertainty with the placement of a weak surface low to the south
and the northward extent of precipitation with very dry air
remaining in place to the north. The 14.12Z ECMWF continues to keep
most of the precip south of the area with dry easterly low-level
flow while the GFS is farthest north with a band of precip
spreading along and south of I-90 Friday evening. Any precip that
does occur would transition to light snow as temps fall below
freezing Friday evening. Although some model soundings hint at a
loss of ice and some freezing rain potential, maintained a
rain/snow scenario for now. High pressure will build back into
the area on Saturday with seasonably mild highs in the 40s.

The main concern for the extended period is a vigorous low pressure
system forecast to eject off the Rockies Sunday into Monday. Before
its arrival, models are in good agreement with an upper-level ridge
axis passing over the Mississippi River Valley Sunday, allowing for
dry weather and above normal temperatures. Surface cyclogenesis is
forecast over western Kansas by Sunday evening, with the low
tracking into the Ohio River Valley by Monday night. This track
would place southern portions our area on the northern edge of the
precipitation shield. This system will need to be monitored, as a
northern shift in storm track could potentially bring impactful
weather to our southern areas. Predictability significantly
decreases beyond this system, but the general model consensus calls
for dry weather under northwest flow aloft and surface ridging
Tuesday into Wednesday.


.AVIATION...(For the 06Z TAFS through 06Z Thursday night)
Issued at 1140 PM CDT Wed Mar 14 2018

High pressure will result in VFR conditions at KRST/KLSE through
the period. Besides some cirrus, expect mostly clear/sunny skies.
Winds will be light and variable at KLSE overnight, increasing
from the north-northeast Thursday. At KRST, light northwest wind
overnight will gradually turn to the northeast Thursday.




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