781
FXUS63 KARX 081703
AFDARX

Area Forecast Discussion
National Weather Service La Crosse WI
1100 AM CST Fri Nov 8 2024

.KEY MESSAGES...

- Dry and mild conditions today.

 - Rain returns to the area Saturday afternoon into Sunday.
   Rainfall amounts are expected to be up to a quarter of an
   inch.

 - Next chance of rain middle of next week.

&&

.DISCUSSION...
Issued at 304 AM CST Fri Nov 8 2024

Today into Sunday night

Latest water vapor satellite imagery shows upper level closed low
over the southwestern United States and shortwave ridge building
into the Upper Mississippi River Valley. Shortwave ridge will
continue to build into the Upper Mississippi River Valley/Upper
Great Lakes Region today into tonight. Mostly sunny skies and
dry weather can be expected across the forecast area today with
high temperatures in the 50s.

Then...upper level closed low over the southwest United States lifts
northeastward into the Upper Great Lakes region late tonight into
Sunday. First piece of energy wrapping around closed low tracks over
the western forecast area Saturday. Isentropic lift in association
with this piece of energy will produce scattered light rain
showers...mainly west of the Mississippi River late Saturday
morning/afternoon. However with atmosphere column dry aloft per
bufkit soundings. This will inhibit and possibly delay any
widespread showers into the western parts of the forecast area
Saturday morning. As upper level closed low moves over the
forecast area/Upper Great Lakes Region Saturday afternoon/night.
Deeper lift/forcing with the closed upper level low will allow
light rain to become widespread over the forecast area late
Saturday afternoon/Saturday night. Upper level closed low tracks
over the Upper Great Lakes region and will continue to wrap
light rain showers over the forecast area Sunday morning. With
the closed low pushing into southern Canada Sunday
afternoon...diminishing light rain chances are expected over the
forecast area Sunday afternoon/evening.

Latest deterministic models/ensemble means indicate precipitable
water values of up to an inch over the forecast area Saturday
afternoon/evening. With the deeper moisture/precipitable water
values south of the forecast area and rain band quickly moving over
the forecast area. Rainfall amounts Saturday afternoon into Sunday
are expected to be up to a quarter of an inch.

Monday through Thursday

Main forecast concerns Monday through Thursday are precipitation
chances Tuesday night into Wednesday. Shortwave trough digs over the
central United States by middle of next week. Latest
ensembles/deterministic models show differences on the strength of
the shortwave...as the ECMWF suggest possible split
northern/southern flow aloft over the central United States and
GEFS/GFS indicate a deepening upper level trough over the central
United States/Upper Great Lakes region middle of next week. These
differences will have impacts on timing/strength of lift/forcing
associated with the shortwave trough. At this time...looks like the
forecast area will receive some precipitation based on moisture
convergence/lift...though if shortwave trough deepens over the Upper
Great Lakes region...precipitation may linger longer over the
forecast area. Temperatures are expected to remain slightly
above to near normal...as the latest NAEFS suggest near zero to
plus 1 degree celsius standard anomaly over the Upper
Mississippi River Valley. High temperatures will be in the
middle to upper 40s to 50s.

&&

.AVIATION /18Z TAFS THROUGH 18Z SATURDAY/...
Issued at 1100 AM CST Fri Nov 8 2024

CIGS: a gradually increase in high clouds overnight, out ahead of an
approaching low pressure system moving northeast out of the plains.
The cigs will continue to thicken and lower through Sat, with short
term guidance favoring a drop into MVFR (possibly IFR) later Sat
night.

WX/vsby: no impacts through Sat morning. Scattered -shra should
spread in Sat afternoon with the aforementioned low pressure system.
On and off showers expected into Sunday morning. Amounts look
minimal through the period (1/4" or less). Guidance holds off on
most of the related vsby impacts until later Sat night.

WINDS: light northerly swing to the east then southwest tonight.
Speeds will pick up for Sat (10 to 15 kts, a few higher gusts near
20 kts possible at KRST).

&&

.ARX WATCHES/WARNINGS/ADVISORIES...
WI...None.
MN...None.
IA...None.

&&

$$

DISCUSSION...DTJ
AVIATION.....Rieck