790
FXUS63 KARX 271934
AFDARX

Area Forecast Discussion
National Weather Service La Crosse WI
234 PM CDT Thu Mar 27 2025

.KEY MESSAGES...

- Scattered shower and thunderstorm risk late tonight and again
  later Friday as record warmth invades the area to close out
  the week.

- Widespread precipitation chances (80-100%) this weekend.
  Precipitation should initially fall as rain before
  transitioning to snow/ice/wintry mix Saturday night into
  Sunday. Uncertainty in winter precipitation location.

&&

.DISCUSSION...
Issued at 233 PM CDT Thu Mar 27 2025

Scattered Shower And Thunderstorm Risk

Evolution of larger scale flow will produce moisture and warm air
advection across much of the region tonight. But subtleties in warm
front position and surface low moving along this boundary will come
into play with convective growth during the overnight hours.

While some of 27/00z model datasets suggested a band of elevated
convection skirting across our area, more recent runs have shifted
this advection area further south and keep a bulk, if not all, of
the convective threat out of the area. Given potential for an
elevated CAPE layer in the 500-1000 J/kg range, will need to be
cautious lowering rain threat too far. If storms do fire along the
nose of this low level front and moisture push, they could produce
hail at times between Midnight and daybreak Friday.

As stronger short wave starts to eject out of evolving larger trough
across the western CONUS on Friday, will see bulk of area get into
the warm sector with decent southwest flow and impressive climb in
temperatures after morning stratus lifts north. Forecast highs could
reach or break daily records for March 28 with favorable low level
wind direction.

Thinking bulk of day will be breezy, warm, and dry tomorrow but as
we get into the afternoon and evening, will have to monitor threat
for any convective showers or evening thunderstorms. Some subtle
hints of higher based showers during the peak heating, but seems
like if anything stronger forms, it would be along frontal boundary
stretched across northern parts of the area during the evening.
MLCAPE values should be back in the 500-1000 J/kg range as we get
surface dewpoints into the mid 50s. But again, trends in CAMS have
been for less and less activity suggesting a more conditional
threat. Any stronger storms along front could produce hail given
such steep lapse rates but that would likely be tied along
front.

Widespread Precipitation Chances This Weekend

Widespread rainfall continues to be expected this weekend
across much of the area (80-100%) as the well advertised 500hPa
trough and associated surface cyclone move through the region. A
widespread 0.5" to 1.5" of total QPF is expected with areas
upwards of 2" possible.

A messy winter precipitation scenario is in store for Saturday night
into Sunday as transition to snow/ice/wintry mix is possible in
response to the warm front sagging southward and another surface low
moving through the region. Concern remains for icing potential,
especially across portions of northern and central Wisconsin, but
notable variations in the placement of the low track Saturday night
into Sunday between the 27.12z EPS/GEFS and their deterministic
counterparts have decreased overall confidence. Two scenarios appear
to play out, the EPS/ECMWF scenario with a more northerly track to
the low and thus a decrease in snow/ice amounts across our area and
the GEFS/GFS scenario with a more southerly track to the low and
thus an increase in snow/ice amounts across our area. Tend towards
the EPS/ECMWF solution given greater run-to-run consistency in this
model, but the GEFS/GFS solution should not be discounted given
greater impacts to the area if it were to play out. So, despite a
possibly favorable set up with an elevated warm nose and cooling
near surface air, the location of the warm front and surface low as
well as the arrival time of cold air will largely determine the
impacts we see regarding freezing precipitation. Rain transitions to
snow across the area Sunday into Sunday night as cold air advects
into the region behind the departing system.

Although nearly a week away, ensemble guidance is beginning to
suggest another spring system moving into the Upper Midwest for the
middle of next week. Plenty of variation exists, so it`s challenging
to say much more for the time being.

&&

.AVIATION /18Z TAFS THROUGH 18Z FRIDAY/...
Issued at 1233 PM CDT Thu Mar 27 2025

Area in between weather systems at the moment, leading to
widespread VFR conditions. But as warm front lifts this way and
associated moisture advection kicks in overnight, will have to
monitor conditions closely for stratus development, and
eventually an elevated convective threat. Most likely scenario
is for MVFR ceilings to develop /50-70%/ but could see some
isolated IFR conditions north of advancing front. Unsure on
extent of shower threat, especially given some trends in recent
updates to keep this south of the area. Honored the potential
setup though with at least a threat for a few hours during the
overnight.

As area gets into the warm sector on Friday, expecting stratus
to lift north or dissipate. Uncertainty exists on how quick this
will happen given some solutions that hold this in longer. But
overall would expect a return to VFR as midday mixing occurs and
front establishes to the north.

&&

.CLIMATE...
Issued at 233 PM CDT Thu Mar 27 2025

Record or near record highs Friday, March 28 (Record/Forecast):

                        High Temp               Warm Low
---------------------------------------------------------------
Rochester, MN         76 (1946) / 79         49 (1977) / 45
La Crosse, WI         80 (1986) / 81         52 (1879) / 44

&&

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

&&

$$

DISCUSSION...Falkinham/Shea
AVIATION...Shea
CLIMATE...Falkinham