Area Forecast Discussion
Issued by NWS La Crosse, WI

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FXUS63 KARX 280829

Area Forecast Discussion
National Weather Service La Crosse WI
329 AM CDT Sun May 28 2023

.DISCUSSION...(Today through Saturday)
Issued at 329 AM CDT Sun May 28 2023

Key Messages:

 - Abnormally warm through the week. Largest high temperature
   anomalies will be from Wednesday through Friday.

 - Dry through Memorial Day. Small rain chances (10-20%) return
   mainly west of the Mississippi River on Tuesday afternoon and
   evening, and a 20-40% chance across the Upper Mississippi River
   Valley for the remainder of the week.

Through Memorial Day...

The eastern CONUS Rex Block will continue to provide dry
weather through Memorial Day. This will be the first 3-day
Memorial Day to remain dry since 2003 for La Crosse WI and
since 2014 for Rochester MN. With only a 3-5 degree spread
in the 25-75th percentile NBM forecast, confidence is also high
(over 90%) that high temperatures will range from around 80 to the
mid-80s through Memorial Day.

As typical, the NBM dew points are on the high side for both today
and Monday afternoons, so went more with the NBM 10th percentile.
This resulted in afternoon humidities ranging from the teens to
lower 20s this afternoon and in the 20s on Monday afternoon.

With dry dew points continuing over the region and the NBM
deterministic being a bit too high over the past couple of
days on it`s low temperatures, used a blend of the NBM and the
25th percentile to lower the low temperatures for both tonight
and Monday night.

Tuesday through Saturday...

The Rex Block will shift east and gradually break down early in
this time period. This will allow a series of weak shortwaves to
move northeast from the Four Corners Region into western Ontario
though Wednesday Night and then a 500 mb ridge develops just
northwest of the Upper Mississippi River Valley. This results in a
small (10-20%) chance of afternoon/evening showers and storms on
Tuesday mainly west of the Mississippi River and a 20-40% chance
of showers and storms for the Upper Mississippi River Valley for
the remainder of the week.

During much of this time period, 850-mb temperatures will range
15-17 C range. This will result in high temperatures ranging from
the upper 80s to lower 90s. With only a 3-5 degree spread
in the 25-75th percentile NBM forecast from Tuesday through Friday
confidence is high (over 80%) on these temperatures. Due to
uncertainty on how far northwest the 500 mb high will be from us,
the spread in the 25-75th percentile increases into the 7 to 10F
range for Saturday`s high temperature. This results in slightly lower
forecast confidence (50-70%) for this day.


.AVIATION...(For the 06Z TAFS through 06Z Sunday night)
Issued at 1015 PM CDT Sat May 27 2023

VFR conditions will persist through the TAF period with
occasional high clouds and generally SE winds at or below 10 kts.
A few higher gusts are possible Sunday afternoon.




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