826
FXUS63 KARX 290510
AFDARX
AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE LA CROSSE WI
1210 AM CDT WED OCT 29 2025
KEY MESSAGES
- RAIN SHOWERS--MAINLY ALONG AND WEST OF THE MISSISSIPPI RIVER
VALLEY--DEPART OVERNIGHT. HIGHEST RAINFALL AMOUNTS OF AROUND A
QUARTER OF AN INCH WILL BE TOWARDS CENTRAL IA/MN WITH A QUICK
DROP OFF IN AMOUNTS TO THE EAST.
- COOLING OFF THROUGH THE WEEK WITH HIGHS FALLING TO THE UPPER
40S TO AROUND 50 BY SATURDAY.
- DRY FOR WEDNESDAY AND THURSDAY WITH THE POSSIBILITY OF LIGHT
SHOWERS (20-30% CHANCE) FOR FRIDAY INTO THE WEEKEND.
DISCUSSION
ISSUED AT 135 PM CDT TUE OCT 28 2025
THIS AFTERNOON - TONIGHT: RAIN, DEPARTING OVERNIGHT
A SURFACE BOUNDARY IS STALLED OVER WESTERN MN/IA EARLY THIS
AFTERNOON AS THE PARENT UPPER TROPOSPHERIC TROUGH UNDERGOES A
BIFURCATION, WITH THE BULK OF THE WAVE ENERGY SLIDING TO THE
SOUTHEAST AND LEADING TO CYCLOGENESIS OVER THE LOWER OHIO RIVER
VALLEY LATER TONIGHT. DRY AIR OFF A GREAT LAKES RIDGE HAS BEEN
ERODING THE EASTWARD FLANK OF THE RAIN SHIELD THIS MORNING,
EFFECTIVELY KEEPING THE RAIN TO THE WEST OF A ROCHESTER TO
CHARLES CITY LINE.
AS THE AFOREMENTIONED SOUTHERN LOW DEVELOPS, A RIBBON OF
THETA-E ADVECTION/ISENTROPIC ASCENT WORKS NORTHWARD OUT OF
ILLINOIS TO HELP GENERATE ANOTHER ROUND OF RAIN THIS AFTERNOON
AND EVENING ALONG AND WEST OF THE MISSISSIPPI RIVER VALLEY,
THROUGH THE QUESTION IS JUST HOW FAR EAST THESE SHOWERS ADVANCE
WITH SOME GUIDANCE FAILING TO BRING MOST OF THE SHOWERS OUT OF
NORTHEAST IOWA/SOUTHWEST WISCONSIN. BY 03Z, THE FLOW TURNS
NORTHEASTERLY AND THE FORCING WANES, RESULTING IN THE RAIN
SHIELD ERODING FROM NORTHEAST TO SOUTHWEST BEFORE SUNRISE.
WEDNESDAY - THURSDAY: DRY, SEASONAL
A PROGRESSIVE NORTHWESTERLY FLOW PATTERN OVERSPREADS THE REGION
IN THE WAKE OF OUR DEPARTING SYSTEM TONIGHT, USHERING IN AN
UPPER TROPOSPHERIC SHORTWAVE RIDGE LATE WEDNESDAY INTO THURSDAY
MORNING WITH THE RIDGE AXIS PASSING THROUGH BY THURSDAY
AFTERNOON. LITTLE CHANGE IN THE BOUNDARY LAYER AIRMASS IS
FORECAST FOR THESE DAYS, RESULTING IN SEASONAL TEMPERATURES
TOPPING OUT IN THE LOW TO MID 50S. CAN'T FULLY RULE OUT FOG
WEDNESDAY NIGHT TOWARDS CENTRAL IOWA/MINNESOTA AS THE SURFACE
RIDGE MOVES OVER ANY SATURATED SOILS FROM THE ONGOING RAIN.
FRIDAY - WEEKEND: COOLER, LIGHT RAIN SHOWERS
AN ELONGATED VORT LOBE/CLOSED LOW SLIDES THROUGH THURSDAY NIGHT
THROUGH FRIDAY, BRINGING A DECAYING COLD FRONT THROUGH THE
REGION. BETWEEN THE FRONTAL PASSAGE AND STEEPENING LAPSE RATES
OWING TO THE POST-FRONTAL COLD AIR ADVECTION, THE SETUP POINTS
TO AT LEAST THE POTENTIAL FOR LIGHT DIURNAL SHOWERS DURING THE
AFTERNOON (LREF MEASURABLE PRECIPITATION PROBS ARE AROUND 30%
AND INCREASING OVER THE LAST 24-30 HOURS).
CYCLONIC FLOW PERSISTS POSSIBLY AS LATE AS SATURDAY AS OUR
PASSING VORT LOBE IS ABSORBED INTO A BROADER, COMPLEX LONGWAVE
TROUGH THAT DEVELOPS THROUGH THE MERGING OF THREE SEPARATE
SHORTWAVES TO THE SOUTH AND EAST. THE MEDIUM RANGE SOLUTIONS ARE
UNDERSTANDABLY STRUGGLING TO RESOLVE HOW THESE WAVES WILL
INTERACT WITH EACH OTHER, RESULTING IN LOW PRECIPITATION
PROBABILITIES FROM THE LREF/NBM. EXPECT THAT THESE PROBABILITIES
WILL BE REFINED OVER THE NEXT FEW DAYS. A POSITIVELY-TILTED
RIDGE SAGS SOUTHEASTWARD AND THROUGH THE FORECAST AREA ON
SUNDAY, FOLLOWED BY A MORE DYNAMIC TROUGH TO START NEXT WEEK
THAT COULD BRING BLUSTERY CONDITIONS AND MORE WIDESPREAD RAIN.
THERE IS LITTLE WARM AIR ADVECTION IN SIGHT IN SUCH A PATTERN,
SO TEMPERATURES SHOULD LINGER NEAR OR SLIGHTLY BELOW NORMAL FOR
THE WEEKEND. A LOOK AT THE LONGER RANGE GEFS/EPS ENSEMBLES SHOWS
SOME SIGNAL FOR FOR THE RETURN OF WARMER WEATHER (HIGHS NEAR
60) NEXT WEEK, BUT THERE EXISTS AMPLE VARIABILITY IN THE
SOLUTIONS.
AVIATION /06Z TAFS THROUGH 06Z THURSDAY/
ISSUED AT 1209 AM CDT WED OCT 29 2025
CIGS: EXPECTATION IS FOR THE LOWER VFR DECK AT KRST TO SHIFT
SOUTHWEST BY 06Z, LEAVING MOSTLY MID LEVEL VFR DECK THROUGH THE
OVERNIGHT. DECK LOOKS TO SCATTER OUT BY MID MORNING WED WITH SCT/SKC
CONDITIONS INTO EARLY THU MORNING.
WX/VSBY: AREAS OF LIGHT RAIN HAVE MANAGED TO SPREAD ACROSS WESTERN
WI BUT RADAR AND CAMS TRENDS SUGGEST THAT THE -SHRA WILL SHIFT
SOUTHWEST BY 06Z FOR BOTH KRST/KLSE. MINIMAL VSBY IMPACTS/ACCUMS.
WINDS: NORTH/NORTHEAST THROUGH THE PERIOD. GENERALLY AT/BELOW 10 KTS
THROUGH WED AFTERNOON...BECOMING LIGHT AS HIGH PRESSURE MOVES
OVERHEAD WED EVENING.
ARX WATCHES/WARNINGS/ADVISORIES
WI...NONE.
MN...NONE.
IA...NONE.
DISCUSSION...SKOW
AVIATION...RIECK
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