Gotham, Wisconsin Weather Forecast Discussion

842
FXUS63 KARX 012316
AFDARX
Area Forecast Discussion
National Weather Service La Crosse WI
616 PM CDT Wed Oct 1 2025
.KEY MESSAGES...
- Dry conditions and above normal temperatures through the
  weekend.
- Low probabilities for showers and perhaps a thunderstorm
  (10-30%) Sunday into early next week.
&&
.DISCUSSION...
Issued at 150 PM CDT Wed Oct 1 2025
Dry Conditions and Above Normal Temperatures
A warm start to October remains on the docket as upper level
ridging remains the primary influence over our weather through
the end of the week and into the weekend. The primary ridge axis
is currently situated over the Great Lakes Region based on the
01.17z RAP analysis, but begins to flatten and transition
eastward today through Friday. Despite this, ridging and low
level high pressure will remain the dominant pattern over the
eastern two-thirds of the United States through the weekend.
Under these features, 925-850hPa temperatures will warm as a
stout thermal ridge extends into the Upper Midwest from the
Central Great Plains associated with southerly flow and
subsidence. Based on the 01.00z LREF, 925hPa temperatures remain
around 24C, which combined with mostly clear skies and adequate
diurnal and turbulent mixing, should allow for surface
temperatures to quickly climb into the mid to upper 80s Friday
and Saturday under this dome of warm air, generally 20 to 25
degrees above normal. Confidence is high regarding these
abnormally warm temperatures as the 01.00z EFI continues to
depict a 90-99% probability of unusually warm temperatures. A
shift of tails of 1 resides across southwest to east-central
Minnesota, but a shift of tails of 0 outlines much of the Upper
Mississippi River Valley, highlighting the potential for
extremely unusual temperatures through the weekend. There is
also very little spread within the 01.13z NBM and 01.00z LREF
regarding maximum and minimum temperatures, on the order of only
a few degrees. Despite the abnormal warmth, record temperatures
appear to be out of reach at Rochester or La Crosse on Friday,
but record high temperatures are in danger of being tied or
broken on Saturday. The current high temperature forecast is 87F
and 85F for La Crosse and Rochester, respectively, with their
respective record high temperatures being 88F and 84F, both set
in 2005.
As we head into the weekend, a shortwave trough will traverse
the flattened ridge, moving northward over the Great Plains and
promoting surface cyclogenesis over the Northern Plains. Strong
850hPa winds will be associated with this system Saturday
afternoon given uninterrupted southerly flow over the Plains
within a tight pressure gradient. These winds should not have
much trouble mixing to the surface given steep low level lapse
rates owing to the warmth and effective diurnal heating, leading
to gusts of 20 to 30 mph over portions of southeast Minnesota
and northeast Iowa. Despite minor differences in the northward
extent of the low over the plains, little variation exists with
regard to the eastward extent. As such, expecting the strongest
winds to remain west of our area. This is beneficial on the fire
weather front as these winds are not expected to coincide with
areas over west-central and southwest Wisconsin into far
northeast Iowa where soils are driest and relative humidity the
lowest. If models were to trend eastward with regard to the low
track, the stronger winds associated with it would be more apt
to coincide with the lower RHs across portions of our area, and
would increase the concern for fire weather effects,
specifically on Saturday. However, their current trajectory
indicates the greatest threat for elevated fire weather
conditions this weekend will be west of our area.
Shower and Storm Probabilities This Weekend and Next Week
There is good consensus regarding the shortwave trough and
associated surface low dragging a cold front through the region
late this weekend into early next week, bringing low
probabilities for showers and storms (10-30%). However, a decreasing
trend in these probabilities is noted across our area given a
dry and capped warm sector laid out over much of the Upper
Midwest. Likewise, instability is lacking along and ahead of the
front in the capped environment while the strongest 0-6km bulk
shear is laid out behind the front. The lack of favorable
environmental conditions should largely hinder convective
development. However, the 01.00z Pangu/FengWu AI/ML models
continue to highlight low probabilities (0-5%) of a stronger
storm along the front, so this remains something to keep an eye
on. Higher confidence comes in the wake of the cold front as
cold air advection will usher in near normal temperatures to the
region by Tuesday.
&&
.AVIATION /00Z TAFS THROUGH 00Z FRIDAY/...
Issued at 616 PM CDT Wed Oct 1 2025
VFR conditions are expected through the TAF period with sct to bkn
clouds between 15kft to 25kft through the overnight. A few diurnal
cumulus with winds from the south to around 8-12 kts will be
predominant late morning into the afternoon on Thursday. Valley
fog overnight and early this morning is very unlikely at KLSE as
the recent RAP has a fairly strong winds just off the deck at
15-25 kts in addition to the upper-level clouds.
&&
.ARX WATCHES/WARNINGS/ADVISORIES...
WI...None.
MN...None.
IA...None.
&&
$$
DISCUSSION...Falkinham
AVIATION...Naylor

NWS ARX Office Area Forecast Discussion