398 
FXUS63 KARX 160339
AFDARX

Area Forecast Discussion
National Weather Service La Crosse WI
1039 PM CDT Sat Oct 15 2022

.DISCUSSION...(This evening through Saturday)
Issued at 245 PM CDT Sat Oct 15 2022

Key Messages:

 - Rain/Snow Shower Chances Tonight Thru Sunday Night

 - Below Normal Temperatures through Next Week

 - Record to Near Record Lows/Low Maximum at Rochester Monday and
   Tuesday Morning

 - Better Consensus for Above Normal Temperatures by Saturday

Through Tonight: Breezy, increasing clouds, and small shower chances 
pre-dawn north:

Regional radar showing the light snow and rain shower area which 
affected northcentral WI for most of the night has shifted 
northeast. Ceilings also rising there as forcing from a strong 
shortwave trough lifts east across the U.P. of MI. Surface analysis 
shows a cold front from DLH-MSP-KFSD at 18Z with the colder air 
still further north in Manitoba and Saskatchewan provinces heading 
southward. GOES visible today showing massive cloudiness upstream 
over MN/Canada with clear skies over much of the local area. With 
northwest flow and the very anomalous deep longwave trough anchored 
north of Lake Superior, that weather is all heading in. 

Winds will be gusting this afternoon and shifting to the northwest 
as the cold front swings through. Cold advection begins, but really 
kicks in later tonight as stronger shortwave trough energy (again) 
arrives from northern Saskatchewan (now). Have introduced small R/S 
chances pre-dawn tonight with lapse rates steepening and showers 
seen in many of the CAMS near and north of I-94.

Extended Overview:

An anomalously cold weather pattern will develop Sunday night and
last through Wednesday. Warming develops Saturday ahead of a cold
frontal passage. A broad trough of low pressure is over much of 
the northern half of the U.S. into Canada. Embedded areas of low 
pressure drop south and deepen the trough through the South 
Atlantic states Tuesday and Wednesday. Meanwhile...as the deep and
broad trough pushes east, a ridge develops across the Plains and 
into the Mississippi Valley Thursday continuing through Saturday.

Sunday through Saturday:
 
With the cold air advection Sunday, forecast soundings show
steepening lapse rates with convective temperatures in the upper
30s and lower 40s. Not as straightforward a situation as others in
that the highest confidence in ice being present for snow is along
and north of I94. The RAP/HRRR as well as the UKMET/EC hint at 
higher chances for instability showers Sunday and early Sunday 
evening east of the Mississippi River. Did increase pops farther 
south to account for these showers and a mix of rain/snow. Will
need to watch things in the short term Sunday with the drier air 
farther south to adjust as needed if we are far enough south with 
the precipitation mention.

Temperatures continue to be 5 to 15 degrees below normal and we
have near record lows and a near record low max forecast at RST
for Monday the 17th. Normal high temperatures are from 55 to 60 
degrees and highs early in the week are only in the 30s and 40s.
The EFI/Shift of Tails shows support for these near record
temperatures and the NAEFS 850mb temperatures remain 2 to 3
standard deviations below normal early next week. There is better
agreement Thursday through Saturday that the pattern will swing to
warmer temperatures, thus have highs returning to the 50s and 60s.

&&

.AVIATION...(For the 00Z TAFS through 00Z Sunday evening)
Issued at 1039 PM CDT Sat Oct 15 2022

Main taf concern is the potential for MVFR conditions at both taf 
sites after 12z Sunday. Upper level low over southern Ontario 
continues to wrap clouds and scattered showers into the region 
through the taf period. Ceilings are expected to lower into MVFR 
conditions...2000 to 3000 feet...after 12z Sunday. Ceilings are 
expected to improve into VFR during the afternoon hours due to 
daytime heating and remain in VFR through the rest of the taf 
period. Winds will remain breezy with wind speeds 10 to 20 knots and 
gust 20 to 25 knots with a couple of brief gust up to 30 knots.

&&

.ARX WATCHES/WARNINGS/ADVISORIES...
WI...NONE.
MN...NONE.
IA...NONE.
&&

$$

DISCUSSION...Baumgardt/Zapotocny
AVIATION...DTJ