Castalia Iowa Weather Forecast Discussion

807
FXUS63 KARX 102327
AFDARX
Area Forecast Discussion
National Weather Service La Crosse WI
627 PM CDT Fri Oct 10 2025
.KEY MESSAGES...
- Areas of frost are possible for portions of central to north-
  central Wisconsin tonight. Otherwise, clear to mostly clear
  skies and dry conditions expected through early Sunday.
- The next shot for showers comes late Sunday into Monday
  (30-60%), but minimal impacts are expected.
- Primarily seasonable temperatures continue through Monday,
  but more uncertainty in the forecast comes by the middle of
  next week.
&&
.DISCUSSION...
Issued at 153 PM CDT Fri Oct 10 2025
Areas of Frost, Clear Skies, and Dry Conditions
A surface cold front has been marching through the Upper Midwest
this afternoon, currently situated from southwest to northeast
Wisconsin, with high pressure sinking southward in its wake.
Drier air advecting into the region under northwest flow in
conjunction with the high pressure will keep our skies clear
this afternoon through much of Saturday with dry conditions
through the same timeframe.
A threat for frost exists for portions of central to north-
central Wisconsin overnight into Saturday morning as favorable
conditions for efficient nocturnal cooling will exist under the
high pressure and clear skies, so temperatures are expected to
drop into the low 30s for these areas. These favorable
conditions combined with light winds under the inversion should
support frost development.
Next Shot For Showers
A negatively tilted shortwave trough ejects into the Northern
Plains Sunday. Warm, moist air advects northward into the Upper
Midwest ahead of this feature, although the 850hPa thermal ridge
axis and associated moisture transport are currently expected
to focus over Minnesota, largely west of our area as drier air
remains situated further east. As such, ensemble guidance
continues its trend towards drier conditions through much of
Sunday with only 10-20% of the 10.00z LREF members hinting at
isolated afternoon showers in southeast Minnesota. Otherwise,
breezy conditions are anticipated west of the Mississippi River
Sunday associated with the synoptically induced low level jet
moving within the warm air advection regime.
Late Sunday into Monday morning, a surface cold front will
quickly move eastward through the region, bringing with it
greater potential for showers (30-60%). Some subtle variations
remain amongst the 10.00z LREF members regarding timing and
amounts, but an overall solid consensus exists regarding the
overnight time period and amounts of 0.1-0.2 inches.
Seasonable Temperatures Through Monday and Increased Uncertainty
Primarily seasonable temperatures remain in place through the
weekend and into the new week apart from Sunday. High
temperatures reach into the low 70s for areas west of the
Mississippi River and south of I-90 on Sunday as the
aforementioned warm air advects northward, generally 5-10
degrees above normal. With the passage of the cold front Monday
morning, highs fall back into the upper 50s to low 60s through
mid week.
By midweek, uncertainty increases in the overall upper level
pattern and thus the eventual surface conditions. The 10.06z
GEFS/ENS ensemble means highlight a low amplitude ridge situated
over the eastern 2/3rds of the United States providing
generally dry conditions through roughly the middle of the week.
Looking to their deterministic counterparts, they diverge
quickly with regard to various shortwave impulses traversing
said low amplitude ridge, leading to the aforementioned
uncertainty in how the weather for the new week will ultimately
play out. However, based upon the 10.00z LREF, the next best
chance for precipitation looks to be around Thursday.
&&
.AVIATION /00Z TAFS THROUGH 00Z SUNDAY/...
Issued at 627 PM CDT Fri Oct 10 2025
VFR expected areawide through at least Saturday night.
&&
.ARX WATCHES/WARNINGS/ADVISORIES...
WI...Frost Advisory from 2 AM to 8 AM CDT Saturday for WIZ042>044.
MN...None.
IA...None.
&&
$$
DISCUSSION...Falkinham
AVIATION...Baumgardt

NWS ARX Office Area Forecast Discussion