Maryville, Iowa Weather Forecast Discussion

514
FXUS63 KARX 071043
AFDARX
Area Forecast Discussion
National Weather Service La Crosse WI
543 AM CDT Sun Sep 7 2025
.KEY MESSAGES...
- Unseasonably cool temperatures today with highs in the upper
  50s to middle to 60s. Then temperatures warm into the 70s by
  middle of this week.
- Showers and a few storms expected Monday afternoon into
  Tuesday. Then mainly dry weather for the rest of the week.
&&
.DISCUSSION...
Issued at 226 AM CDT Sun Sep 7 2025
Today through tonight
Latest surface analysis shows ridge of high pressure extending from
northern Missouri into northern Minnesota. The surface ridge will be
the dominant weather feature across the forecast area today.
Subsidence under surface will allow for mostly sunny skies...light
winds (less than 10 miles per hour) and dry weather across the
forecast area. Temperatures will remain unseasonably cool as latest
NAEFS suggest standard anomalies of minus 2 to minus 4 degree
celsius over the region. High temperatures are expected to be in the
upper 50s to middle 60s.
Monday into Tuesday night
Ridge axis builds east of the area and southerly flow aloft develops
over the Northern Plains/Upper Great Lakes Monday. Shortwave trough
moves into Northern Plains Monday afternoon/night. The latest 07.00z
GFS/ECMWF/NAM show decent moisture convergence with the shortwave
trough. The axis of moisture convergence is over west central
Wisconsin/eastern part of Minnesota and the far northwest portions
of the forecast area will be on the fringe of this axis Monday
evening. As shortwave trough slowly pushes east this moisture axis
will track over the forecast area and spread convection into the
area Monday night. Forcing/vertical motion...moisture convergence
wanes across forecast area Tuesday and convection will diminish
during the day. CAPE is limited with the shortwave trough...as
suggest 0-6km most unstable CAPE of 100-200 j/kg over the
northwest/western parts of the forecast area with the main axis of
instability west of the forecast area. Coverage of storms should be
isolated to scattered across the forecast area Monday evening into
Tuesday morning. Any storms that develop should remain below severe
limits...as CAPE is limited below 500 j/kg surface/elevated CAPE and
0-3km shear is less than 20 knots.
Wednesday through Saturday
The latest deterministic models are in decent agreement Wednesday
through Friday on building upper level ridge over the central United
States/Northern Plains States. Then...the models/ensembles are in
disagreement on when upper level ridge breaks down and placement of
upper level troughs/lows. Subsidence underneath upper level ridge
will provide mainly dry weather across the forecast area Wednesday
through Friday. Temperatures will be warmer...as warmer air aloft
advects into the region. 07.00z ECMWF/GFS indicate 925mb
temperatures warming to plus 15 to plus 18 degrees celsius by 12z
Friday. High temperatures are expected to climb into the 70s and
possibly in the low 80s at few locations late in the week. With
upper level ridge breaking down Friday night into Saturday there is
the possibility of some showers or storms moving into the area.
However...confidence is low on precipitation chances...based on how
fast the ridge breaks down and placement of upper level troughs/lows
over the northern tier United States.
&&
.AVIATION /12Z TAFS THROUGH 12Z MONDAY/...
Issued at 543 AM CDT Sun Sep 7 2025
Fog and low stratus have developed over some tributaries and
portions of north-central WI, but not within the main Mississippi
River channel. Therefore LSE and RST are expected to remain VFR
through this TAF period with some fair weather diurnal cumulus.
Light winds, mainly out of the northwest today, will become
southerly tonight.
&&
.ARX WATCHES/WARNINGS/ADVISORIES...
WI...None.
MN...None.
IA...None.
&&
$$
DISCUSSION...DTJ
AVIATION...Kurz

NWS ARX Office Area Forecast Discussion