Granton, Wisconsin Weather Forecast Discussion

860
FXUS63 KARX 050531
AFDARX
Area Forecast Discussion
National Weather Service La Crosse WI
1231 AM CDT Sun Oct 5 2025
.KEY MESSAGES...
- Low end elevated fire weather conditions for croplands
  in northeast Iowa and southeast Minnesota possible this
  afternoon and tomorrow afternoon.
- Rain very likely (60-90%) Sunday afternoon through Monday night.
- Frost possible (up to 30-60%) in central Wisconsin
  Wednesday and/or Thursday mornings.
&&
.DISCUSSION...
Issued at 207 PM CDT Sat Oct 4 2025
Low end elevated fire weather conditions for cropland
Today into tomorrow, lee cyclone currently developing in NE CO will
advance to western Ontario as a southwesterly upper jet advances
downstream over the central and northern Plains. This should help
maintain a decent surface pressure gradient across the CWA allowing
breezy conditions, already present west of the Mississippi valley
early this afternoon. While breezy conditions are present,
700/850/925mb flow pattern is bringing a bit of additional moisture
to the region, limiting RH falls with values 40 percent or greater
currently. Additionally, grasses and trees remain largely green but
some curing is occurring in cultivated croplands. Thus, fire weather
conditions this afternoon have been low end elevated, if that,
largely driven by the winds and limited to landscapes dominated by
croplands - mainly locations west of the Mississippi River valley.
Will thus not expand the SPS for elevated fire weather.
Moving ahead to tomorrow, similar setup with the breezy conditions
needed for elevated fire weather but limited drops in RH and the
same concerns about spotty receptive fuels. Unlike today, reduction
in heights aloft and thus high temperature potential along with
increasing cloudiness will preclude potential for a record high and
should keep fire weather conditions from becoming truly elevated.
Rain chances Sunday afternoon into Monday night
Sunday afternoon into Monday night, a cold front slides southeast
through the forecast area. With the area progged to be under the
right entrance region of an upper jet as the front pushes through,
should get just enough lift for showers and a few thunderstorms to
develop. Given consistent signal across the 04.12z guidance suite
and between the past few runs, have increased PoPs above NBM toward
short term consensus values of 70-90%. While 04.12z GFS PWAT values
close to 1.4" suggest heavy downpours could occur, consistent
forward motion of the front and thus the region with strong enough
lift for precip suggests limited potential for training storms.
Finally, with winds aloft increasing markedly, deep shear will
certainly be supportive of organized convection, but the limited
instability should keep things in check.
Frost potential Wednesday and/or Thursday mornings
As the longwave upper trough departs, high pressure should build
over the Upper Midwest/Great Lakes Tuesday night into Thursday.
Should this feature be centered in or close to our CWA early
Wednesday morning or Thursday morning, temperatures could plunge far
enough for frost potential. Guidance is beginning to converge on
Wednesday morning being the more probable morning of the two with
04.00z NBM probabilities for lows 36 or lower at 30-60% east of the
Mississippi River valley.
&&
.AVIATION /06Z TAFS THROUGH 06Z MONDAY/...
Issued at 1230 AM CDT Sun Oct 5 2025
A tight pressure gradient at the surface and aloft will result
in sustained south winds between 15 and 25 knots and wind gust
of 25 to 35 knots through 05.22z at KRST and between 15 and 20
knots and wind gust of 20 to 25 knots through 05.21z at KLSE.
A band of showers will move into KRST between 05.22z and 06.04z
and into KLSE between 06.01z and 06.07z.
&&
.CLIMATE...
Issued at 652 PM CDT Sat Oct 4 2025
October 4 Warm Record Lows:
        La Crosse: 72 (2005)/ 66
        Rochester: 71 (2005)/ 68
&&
.ARX WATCHES/WARNINGS/ADVISORIES...
WI...None.
MN...None.
IA...None.
&&
$$
DISCUSSION...Ferguson
AVIATION...Boyne
CLIMATE...Boyne

NWS ARX Office Area Forecast Discussion