522
FXUS63 KARX 190338
AFDARX
AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE LA CROSSE WI
1038 PM CDT FRI APR 18 2025
KEY MESSAGES
- WIDESPREAD RAIN IS STILL LOOKING ON TRACK FOR SUNDAY AFTERNOON
INTO EARLY MONDAY. AMOUNTS AROUND AN INCH ARE LIKELY WITH
RIVER RISES, AND WORST CASE SCENARIO SUGGESTING A VERY LOW
CHANCE FOR REACHING MINOR FLOOD STAGE ON SOME WI RIVERS (LESS
THAN 10%). SNOW MAY MIX IN, BUT LOOKS UNLIKELY TO ACCUMULATE.
- WARMING NEXT WEEK INTO AT LEAST THE 60S.
DISCUSSION
ISSUED AT 140 PM CDT FRI APR 18 2025
EASTER SUNDAY AND MONDAY
A VIGOROUS SYSTEM LIFTS THROUGH THE UPPER MISS VALLEY / GREAT LAKES
ON SUNDAY WITH PROBABILITIES FOR RAIN INCREASING DURING THE
AFTERNOON BUT PEAKING SUNDAY NIGHT ACROSS THE ENTIRE AREA. THE
RAINFALL LOOKS TO MOVE OUT MONDAY MORNING. REVIEWING SOME OF THE
LATEST ENSEMBLE PROBABILITY DATA FOR RAINFALL AMOUNTS FROM THE
18.06Z ECMWF AND GEFS, GENERAL AGREEMENT EXISTS WITH HIGH
CONFIDENCE OF AT LEAST 0.50" ACROSS THE AREA. PROBABILITIES FOR
AN INCH OR MORE ARE IN THE MIDDLE RANGES OF 40-60% - WITH THE
EC (GEFS) ON THE HIGHER (LOWER) END OF THE RANGE. THE GEFS
M-CLIMATE COMPARISON TO THE 2000-2019 PERIOD ALSO SUGGESTS AN
"ABOVE NORMAL" EVENT BUT NOT RECORD FOR RAINFALL (WHICH ARE
MOSTLY 1.5-2" FOR THIS TIME OF YEAR). DETAILS ON THE AMOUNTS AND
LOCATION WILL STILL DEPEND ON THE SYSTEM TRACK AND INTENSITY OF
THE LOW, BUT WITH A NEGATIVELY TILTED SYSTEM WITH STRONG
MERIDIONAL MOISTURE ADVECTION AND EXCELLENT CURVATURE TO THE
HEIGHT FIELD ALOFT...FAVORABLE INGREDIENTS ARE IN PLACE. THE
CLIMATOLOGY RANK FOR THE PRECIPITABLE WATER INFLOW TO THE LIFT
(AT DVN) IS 92-98TH PERCENTILE FOR VALUES OF 1-1.2" PER BOTH
ENSEMBLE SYSTEMS. SEE THE RIVER RESPONSE DISCUSSION IN THE
HYDROLOGY SECTION BELOW.
SURFACE-BASED INSTABILITY REMAINS WELL SOUTH OF THE AREA (I-80
OR SO) WITH SOME LIMITED INSTABILITY ALOFT FOR EMBEDDED
THUNDERSTORMS SUNDAY NIGHT PER ENSEMBLE GUIDANCE. THE 18.06Z
ECMWF ENS SUGGESTS A 20% PROBABILITY OF MUCAPE OF 200+ J/KG
TOWARD THE MOISTURE SOURCE SOUTH OF I-90. THUS, THIS IS MAINLY A
RAIN SYSTEM WITHOUT A SEVERE THUNDERSTORM THREAT.
THERE IS A VERY SMALL PROBABILITY OF SNOW ON THE NORTH SIDE
DEFORMATION ZONE OF THE CYCLONE WHICH WOULD POSSIBLY AFFECT THE
I-94 CORRIDOR INTO SOUTHEAST MN (WORST CASE SCENARIO). THE
LATEST 18.12Z GEFS HAS A 10% CHANCE FOR 1"+ OF SNOW BY MONDAY
MORNING FROM ROCHESTER MN TO WAUSAU WI AND NORTH, WITH THE EC
ENS SUGGESTING THOSE PROBABILITIES ARE IN NORTHERN WI.
WARMER NEXT WEEK!
IT SEEMS THE AREA WILL BREAK OUT INTO A BIT WARMER TEMPERATURES
TUESDAY-FRIDAY WITH MORE SUN THAN CLOUDS AND SOME SMALL RAIN
CHANCES. THE NATIONAL BLEND OF MODELS SUGGESTS THERE IS A 75% CHANCE
OF BEING ABOVE THE LOW 60S FOR HIGH TEMPERATURES. THE HIGHEST
RAIN CHANCES OF THE WEEK LOOK LIKE TUESDAY AND TUESDAY NIGHT (~50%).
AVIATION /06Z TAFS THROUGH 06Z SUNDAY/
ISSUED AT 1035 PM CDT FRI APR 18 2025
MVFR CEILINGS EAST OF THE MISSISSIPPI RIVER CLEAR OUT BEFORE
SUNRISE WITH VFR CONDITIONS FOR THE REMAINDER OF THE TAF PERIOD
OUTSIDE OF A BRIEF WINDOW OF MVFR CEILINGS EAST OF A BCK TO OVS
LINE AROUND MIDDAY. WINDS REMAIN FROM THE NORTHWEST BETWEEN 5
TO 15 KTS THROUGH THE DAY, HIGHEST WEST OF THE MISSISSIPPI
RIVER. WINDS BECOME LIGHT OVERNIGHT SATURDAY AND START TO VEER
TO THE NORTH AND EAST.
HYDROLOGY
ISSUED AT 140 PM CDT FRI APR 18 2025
RIVER RISES ARE EXPECTED FROM THE RAIN SUNDAY INTO EARLY MONDAY,
ESPECIALLY WITH SOME RAINS THIS MORNING OF 1-2" ACROSS THE AREA
MAKING FOR MORE MOIST SOILS. THE LATEST RIVER FORECAST CENTER
ENSEMBLE RIVER FORECASTS SUGGEST THE EVENT TOTAL RAINFALL
AMOUNTS WOULD HAVE TO GET CLOSER TO 2" FOR RIVERS TO BE PUT INTO
MINOR FLOOD STAGE...AND THAT IS MAINLY FOR RIVERS IN WISCONSIN.
AT THIS TIME, THAT WOULD BE A LESS THAN 10% CHANCE, AND NEAR
DAILY RAINFALL RECORDS.
ARX WATCHES/WARNINGS/ADVISORIES
WI...NONE.
MN...NONE.
IA...NONE.
DISCUSSION...BAUMGARDT
AVIATION...SKOW
HYDROLOGY...BAUMGARDT
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