552
FXUS63 KARX 241956
AFDARX

Area Forecast Discussion
National Weather Service La Crosse WI
256 PM CDT Fri May 24 2024

.KEY MESSAGES...

- Shower and thunderstorm chances continue this afternoon. There
  is a conditional risk for a few (strong to) severe storms,
  but we will continue monitoring conditions and trends through
  the afternoon/early evening to determine the likelihood of
  severe weather.

- Additional showers and storms return to the forecast Sunday
  (60- 95%). Higher risk for severe weather looks to remain
  further south right now, but heavier rainfall may be possible.

&&

.DISCUSSION...
Issued at 256 PM CDT Fri May 24 2024

This Afternoon - Tonight:

Quite a busy day to start as showers and thunderstorms have
continued to push eastward. Current radar this early afternoon does
show some redevelopment in its wake ahead of the cold front. A
challenging forecast for this afternoon still remains as there
continues to be some uncertainty on the degree of destabilization we
will see through the late afternoon with the ongoing convection as
well as current cloud cover. Latest hi-res model guidance is still
trying to suggest further development late this afternoon/early
evening, but continues to shift it east of the area fairly quickly.
If sufficient destabilization is realized and more robust cells are
able to form some scattered strong to severe storms cannot be ruled
out, with the higher threat in our area appearing to be more
confined across southwest WI. Will be monitoring carefully to see
how trends evolve through the rest of the afternoon. In addition,
some heavier rainfall has been reported this afternoon with some
storms especially in our south. With the recent rainfall and rounds
of storms today the flood watch has been maintained for a couple
areas through the early evening.

Saturday - Memorial Day:

Behind today`s system, the local area looks to get a quick break as
into Saturday as surface high pressure moves eastward across the
region. However, rounds of shortwave energy are forecast to eject
across the region through the period. In addition, model guidance
shows increasing moisture with PWATs generally 1-1.5" and a strong
LLJ (40-50+kt) nosing into the region. With this shower and storm
chances begin to move in late Saturday night, with chances
increasing (60-95%) into the day on Sunday. There still appears to
be a bit of variability among individual ensemble solutions on the
exact placement of the attendant surface low expected to track
northeast and into the Great Lakes region through the period. In
turn there is uncertainty in how far northward greatest instability
may get. Right now, the latest GEFS and ECMWF ens would suggest
highest CAPE values remain just to our south, but with the
previously mentioned uncertainties will need to continue to monitor
especially if any storms do develop near the surface low. Further,
GEFS and ECMWF ens continue to show some probabilities generally 20-
50% for 24-hr QPF >= 1" on Sunday. Overall, will be keeping an eye
on trends especially as hi-res guidance comes into range for any
potential hydro/severe weather impacts to the area.

Some shower and storm chances (20-40%) continue into Memorial Day
and perhaps Tuesday with the additional shortwaves diving down
across the region. Otherwise, highs to start the week are forecast
in the 60s to low 70s.

Next Week:

As we head into mid-week, model guidance has been suggesting upper
level ridging building across the Plains. This looks to bring the
potential for a bit quieter and perhaps drier conditions to the
local area for a short time. Still quite a bit of variability, but
some hint for a very slight increasing trend in temperatures mid-
week into the weekend. Generally maintaining highs in the upper 60s
to 70s and increasing to the mid to upper 70s towards the end of the
week.

&&

.AVIATION /18Z TAFS THROUGH 18Z SATURDAY/...
Issued at 110 PM CDT Fri May 24 2024

Current observations across the area shows variability in
conditions as showers and thunderstorms continue to push
eastward, with some redevelopment beginning to be noted on
current radar mosaic. There still remain some uncertainties in
the extent of redevelopment of these showers and storms this
afternoon. With model guidance continuing to suggest further
eastward development have not added a mention at KRST. Even so,
lower confidence in development/coverage and thunder potential
around KLSE will maintain the VCSH. Will be monitoring with
near/short- term updates more likely. Upstream observations
suggest there may be some periods of MVFR ceilings possible, but
a return to VFR is expected and will remain through the TAF
period. Otherwise, increased winds look to lighten some into tonight,
shifting more southwest by Saturday morning.

&&

.HYDROLOGY...
Issued at 303 AM CDT Fri May 24 2024

Collaborated with WFOs Des Moines and Davenport to issue a
flood watch for portions of northeast Iowa given the potential
for repeated rounds of storms today. Some of the high resolution
models indicate potential for localized amounts of 2-3" of
rain, and given recent rainfall and 3-hr flash flood guidance of
1.75 to 2.00", flooding could develop if the higher amounts are
realized.

&&

.ARX WATCHES/WARNINGS/ADVISORIES...
WI...None.
MN...None.
IA...Flood Watch until 4 PM CDT this afternoon for IAZ029-030.

&&

$$

DISCUSSION...EMS
AVIATION...EMS
HYDROLOGY...JM