505
FXUS63 KARX 201017
AFDARX
AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE LA CROSSE WI
517 AM CDT FRI MAR 20 2026
KEY MESSAGES
- WARM INTO SATURDAY WITH DAYTIME HIGHS FROM THE 50S TO 60S FOR
FRIDAY INCREASING INTO THE 60S AND UPPER 70S FOR SOME ON
SATURDAY. SEE CLIMATE SECTION BELOW FOR LOCAL CLIMATE SITES
RECORDS AND CURRENT FORECAST.
- LIGHT PRECIPITATION CHANCES (10-25%) SATURDAY NIGHT THROUGH
SUNDAY LIKELY WILL REQUIRE AN INCREASE IN COMING FORECAST
PACKAGES.
- MORE SEASONABLE TEMPERATURES THROUGH NEXT WEEK WITH LOW
CONFIDENCE (10%) IN PRECIPITATION POTENTIAL MIDDLE AND LATE
WEEK.
DISCUSSION
ISSUED AT 1037 PM CDT THU MAR 19 2026
POTENTIAL RECORD WARMTH INTO THE WEEKEND:
WARMING TEMPERATURES INTO THE EARLY WEEKEND, FROM BUILDING HEIGHTS
IN A WEST COAST UPPER LEVEL RIDGE ADVECTING EAST THROUGH THE
CENTRAL CONUS ON GOES WATER VAPOR IMAGERY LOOPS THIS EVENING,
CONTINUES TO BE THE MAIN FORECAST DETAIL. THE OVERACHIEVING TODAY
(THURSDAY) TEMPERATURES NOT ONLY PROVIDED AMPLE SNOW MELT TO
DROP LOCAL ALBEDO BUT ALSO EXEMPLIFIED A SEASONAL NBM COOL
TEMPERATURE BIAS IN THE CURRENT REGIME. THEREFORE, IN COLLABORATION
WITH NEIGHBORING FORECAST OFFICES, HAVE BUMPED DAYTIME HIGH
TEMPERATURES UP A FEW DEGREES USING 75TH+ PERCENTILE NBM BLENDS.
WHILE THIS SEEMINGLY BREAKS THE MOLD COMPARED TO MODEL
GUIDANCE, OBSERVATIONS AND TRENDS SUPPORT THIS FORECAST
ADJUSTMENT. RESULTANT HIGHS LOCALLY FROM THE MID 50S TO UPPER
60S FRIDAY AND 60S TO UPPER 70S SATURDAY. THEREFORE, RECORD
DAYTIME WARMTH LOOKING MORE POSSIBLE ON SATURDAY, SEE CLIMATE
SECTION BELOW FOR LOCAL CLIMATE SITE RECORDS COMPARED TO CURRENT
FORECASTS.
LOW PRECIPITATION CONFIDENCE THIS WEEKEND:
THE RIDGE WILL BREAK THROUGH THE LATE WEEKEND, ALLOWING A COLD
FRONTAL BOUNDARY TO SAG SOUTH THROUGH THE UPPER MISSISSIPPI RIVER
VALLEY. WHILE INTRAENSEMBLE TRENDS EXHIBIT PERSISTENT AGREEMENT
OVER THEIR RECENT RESPECTIVE RUNS, INTERENSEMBLE CONSENSUS HAS
WEAKENED FOR PRECIPITATION CHANCES SATURDAY NIGHT INTO SUNDAY.
THE LOWEST PROBABILITIES (10-40% 0.01" QPF/24HR) IN THE GEFS
(19.18Z), DECREASING IN PREVIOUS RUNS, DUE TO A STRONGER, LATER
SOLUTION FOR WEAKENING OF THE HIGH PRESSURE CENTERED OVER THE
DESERT SOUTHWEST, IRONICALLY DISAGREES MOST STRONGLY WITH ITS AI
COUNTERPART (GEFS AI 19.18Z) WHICH PAINTS A WIDESPREAD 60-80%
FOR SIMILAR 0.01" QPF/24HRS SATURDAY NIGHT THROUGH SUNDAY. WHILE
THE EPS (19.18Z) SLIGHTLY DIFFERS IN PROBABILITIES (50-90%)
FROM ITS AI COUNTERPART'S (ECMWF AIFS 19.18Z) PROBABILITIES
(40-80%) FOR 0.01" QPF IN 24 HOURS, INTERINTRAENSEMBLE TRENDS
HAVE BOTH BEEN ON THE INCREASE OVER RECENT RUNS. REGARDLESS OF
THE CONFUSING DICHOTOMY, BESIDES THE GEFS (18.19Z), ALL
AFOREMENTIONED LONG TERM GLOBAL ENSEMBLES (GEFSAI, EPS,
ECMWFAIFS) NOW FLIRT LIMITED PROBABILITIES (10-30%) FOR HIGHER
RAINFALL AMOUNTS (0.1" QPF/24HRS) IN THE HEADWATERS OF
WISCONSIN. CURRENT FORECAST PACKAGE AND WPC COLLABORATION KEEPS
5- 25% POPS ACROSS THE FORECAST AREA IN A LIMITED WINDOW
SATURDAY NIGHT.
MORE SEASONABLE TEMPERATURES THROUGH THE NEW WEEK:
AS THE SYNOPTIC HIGH PRESSURE LOCKS IN A MORE SEASONABLE AIRMASS
LOCALLY THROUGH THE START OF THE WEEK, PRECIPITATION CHANCES
RETURN THROUGH THE MIDDLE AND LATER NEXT WEEK AS THE BAROCLINIC
BOUNDARY STREWN NEAR THE FORECAST AREA GETS ITS ACT TOGETHER AND
NORTHWEST FLOW PROVIDES FORCING FOR POTENTIAL CYCLOGENESIS.
CURRENT CONFIDENCE KEEPS BEST FORCING WELL NORTH OF THE FORECAST
AREA, PASSING FILAMENTS OF INCREASED MOISTURE THROUGH THE UPPER
MISSISSIPPI RIVER VALLEY.
AVIATION /12Z TAFS THROUGH 12Z SATURDAY/
ISSUED AT 516 AM CDT FRI MAR 20 2026
A COLD FRONT WILL MOVE THROUGH THE AREA OVERNIGHT AND FRIDAY
MORNING. THIS WILL ONLY CAUSE A WIND SHIFT FROM SOUTH TO
NORTHWEST TODAY. THE WINDS WILL THEN SHIFT BACK TO THE SOUTH
TONIGHT. OTHERWISE, CEILINGS AND VISIBILITIES WILL BE VFR.
CLIMATE
ISSUED AT 1037 PM CDT THU MAR 19 2026
POTENTIAL RECORD WARMTH ON SATURDAY, MARCH 21ST, 2026:
FORECAST / RECORD HIGH
ROCHESTER, MN: 75 / 70 (1918)
LA CROSSE, WI: 74 / 75 (2022)
ARX WATCHES/WARNINGS/ADVISORIES
WI...NONE.
MN...NONE.
IA...NONE.
DISCUSSION...JAR
AVIATION...BOYNE
CLIMATE...JAR
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