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000
FXUS63 KARX 121136
AFDARX

Area Forecast Discussion
National Weather Service La Crosse WI
636 AM CDT Fri Apr 12 2024

.KEY MESSAGES...

- Weekend: A breezy day today with afternoon gusts of 30-35 mph.
  Sunny and less breezy Saturday /15-25 mph/ with temperatures
  warming into upper 60s to mostly 70s. Ditto Sunday with a bit
  less wind.

- An active weather pattern early next week with a warm Monday,
  then rain/storms looking likely (60-90%) Monday night into
  Tuesday night, with severe storms possible, and turning windy.
  Keep weather aware.

&&

.DISCUSSION...
Issued at 305 AM CDT Fri Apr 12 2024

A Pleasant Weekend

Ridge building begins today with Wisconsin still under the
influence of the western side of the amplified large scale
trough over the eastern CONUS. This will provide some very weak
instability to eastern WI causing afternoon clouds with any
minor shower chances just east of central WI. Breezy conditions
continue with afternoon mixing depths to 800 mb with CAM
consensus of wind gusts of 30-35 mph in the afternoon.

Ridging is then in place for the weekend with breezy southerly
flow and strong warm advection in the low-levels Saturday,
ahead of a weak northwest flow shortwave trough sliding through
north of the Great Lakes. Noticeable afternoon winds of 15 to 25
mph still on Saturday. A cold front slides through with a north
wind shift for Sunday and drier air coming in. Under cold
advection, temperatures will still remain similar to Saturday
with slightly higher mixing heights forecast. Some small rain
chances remain north of I94 for very elevated sprinkle showers.

Strong Storm Impacts the Region Monday Night into Wednesday

Confidence continues to be higher that a strong storm will
impact the Upper Midwest early next week. Big picture agreement
in the latest ensemble model guidance is higher, but the details
on this storm will determine severe storm chances and higher
impacts. Colorado lee cyclogenesis begins Monday, with surging
moisture, precipitable water in the 95-97 percentile range
surging northward into the area Monday night /near record in
many 11.18Z ECMWF ens members/. There is good consensus for
this warm frontal surge and onset of storms/rain late Monday
night into Tuesday morning. Monday though will be another
beautiful warm day it appears.

There remains some moderate spread on the track of this system
with the 12.00Z EC ensembles showing occluding/filling/weakening
surface lows from Grand Forks ND to the Quad Cities Tuesday
night. However, the trend over the past 24 hours is less spread
with the density of surface lows focusing on a track through
~MSP, placing much of the area in a favorable area for severe
storms southeast of the low center. This is very much like the
12.00Z ECMWF deterministic model run...which places the warm
front along I-94 later Tues afternoon. However, the warm sector
is very saturated with low skinny MUCAPE < 500 J/Kg with
ongoing precipitation Tuesday. This is confirmed by the 12.00z
EC ens probability of 500 J/Kg of CAPE zero line just into srn
WI Tuesday later afternoon. These details on severe storms will
need to come out as we get later into the weekend...but right
now it looks more likely a 1-2" rainy system with winds gusting
to 40 mph Tuesday. Those forecast wind gusts have trended lower
over the past 24 hours. Stay tuned!

Cooler Pattern Setting Up For Later In Week

Longwave troughing over the Great Lakes looks probable for the
later part of the week and thus temperatures will be near or
below normal.

&&

.AVIATION /12Z TAFS THROUGH 12Z SATURDAY/...
Issued at 700 AM CDT Fri Apr 12 2024

VFR expected to prevail through the 12.12Z TAF period. Mid level
cloud deck early this morning on satellite imagery expected to
erode through the late morning as cumulus expected to build
towards peak daytime heating.

Noteworthy impact will be winds through today. Overnight winds
underperformed compared to previous forecasts, although daytime
mixing may potentially push winds to overperform. Have slightly
lowered winds this morning using newest high resolution model
guidance.

&&

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

&&

$$

DISCUSSION...Baumgardt
AVIATION...JAR