646
FXUS63 KARX 051123
AFDARX
AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE LA CROSSE WI
523 AM CST THU MAR 5 2026
KEY MESSAGES
- VERY LOW (<20%) RAIN CHANCE THURSDAY.
- RAIN NEARLY CERTAIN (99%) FOR FRIDAY MORNING. A CHANCE FOR
THUNDERSTORMS FOR FRIDAY EVENING, WITH SOME OF THESE
POTENTIALLY SEVERE. THERE IS A 40 TO 70% CHANCE FOR AT LEAST
1" OF RAIN TO FALL FRIDAY INTO SATURDAY.
DISCUSSION
ISSUED AT 1208 AM CST THU MAR 5 2026
VERY LOW POTENTIAL FOR RAIN THURSDAY IN NORTHEAST IOWA AND SOUTHWEST
WISCONSIN
WAVE CURRENTLY OVER NE KS ROLLS EAST-NORTHEASTWARD TOWARD NORTHERN
IN BRINGING AN AREA OF SHOWERS, CURRENTLY DEVELOPING IN NW MO, WITH
IT. SLOW TREND ACROSS THE PAST 4 RUNS OF GUIDANCE, CONTINUING INTO
THE 05.00Z GFS/NAM, HAS BEEN FOR A SLIGHTLY FARTHER SOUTH
TRAJECTORY, KEEPING RAIN LARGELY OUT OF OUR FORECAST AREA. GIVEN
THIS AND CAM OUTPUT, HAVE CUT MENTIONS OF PRECIP ACROSS ALL BUT
PORTIONS OF GRANT/CLAYTON COUNTIES.
RAIN NEARLY CERTAIN FRIDAY MORNING, POTENTIAL FOR SEVERE STORMS IN
THE EVENING
LARGE WESTERN TROUGH BREAKS EASTWARD OVER THE PLAINS FRIDAY WITH AN
ASSOCIATE SURFACE LOW DEVELOPING IN EASTERN CO AND QUICKLY MOVING
NORTHEASTWARD TO LAKE SUPERIOR. LEAD DISTURBANCE IN THE
SOUTHWESTERLY FLOW ALOFT LOOKS TO EJECT DOWNSTREAM OVER THE CWA
DURING THE MORNING HOURS. WITH MULTIPLE DAYS OF SOUTHERLY MOIST
ADVECTION OCCURRING AHEAD OF THIS FEATURE, WIDESPREAD RAIN WILL
ALMOST CERTAINLY (99%) RESULT. LOCALIZED RAIN RATES MAY BE HIGH,
PARTICULARLY FOR EARLY MARCH, AS PROGGED PWAT VALUES UPWARD OF 1"
ARE NEAR THE TOP END OF CLIMATOLOGY. FINAL AMOUNTS ACROSS FRIDAY AND
EARLY SATURDAY WILL BE AROUND 0.5-0.9" PER 05.00Z REFS MEAN VALUES
WITH AN DECENT (40-70%) CHANCE TO REACH 1" AND A SMALL (10%) CHANCE FOR
LOCALIZED SPOTS TO APPROACH 2" SHOULD A THUNDERSTORM TRACK OVERHEAD.
SOME RISES ON CREEKS AND STREAMS WILL OCCUR AS, WHILE WARM
TEMPERATURES CONTINUE THURSDAY AND FRIDAY, SIGNIFICANT FROST DEPTH
REMAINS IN MANY LOCATIONS AND OUR RECENT SNOW BANDS HAVE LEFT A GOOD
CHUNK OF THE AREA NOT COMPLETELY WITHOUT SNOWPACK YET.
AS FOR THE THUNDERSTORM POTENTIAL, MORE SIGNS ARE STARTING TO POINT
TOWARD MOST OF THE FORECAST AREA BEING IN THE WARM SECTOR DURING THE
LATE AFTERNOON AND EVENING AS THE AFOREMENTIONED SURFACE LOW RACES
NORTHEASTWARD. CLUSTER ANALYSIS OF OLDER DATA (04.12Z LREF) HAD
ABOUT 47% OF MEMBERS WITH THE WARM FRONT NORTH OF OUR CWA WHILE THE
REMAINING 53% HAD THIS ABOUT HALFWAY THROUGH THE CWA. REFLECTING
THIS TREND, 05.00Z NAM HAS A NOTICEABLE SHIFT NORTHWARD FROM ITS
PREVIOUS SOLUTION WHICH ONLY HAD FAYETTE/CLAYTON/GRANT COUNTIES
SOUTH OF THE WARM FRONT DURING THE LATE AFTERNOON AND EARLY EVENING.
GIVEN THESE TRENDS IN PARAMETERIZED GUIDANCE AND OUTPUT FROM THE
05.00Z REFS/HREF, THINKING THUNDERSTORMS ARE AN INCREASINGLY GOOD
BET (50% FOR NOW). SHOULD THUNDERSTORMS OCCUR, STRONG SOUTHWESTERLY
WINDS ALOFT COMBINED WITH THE SOUTHERLY WINDS AT THE SURFACE FAVORS
GREATER THAN 50 KNOTS OF DEEP LAYER SHEAR. WITH COLD TEMPERATURES
ALOFT TYPICAL OF MARCH, THIS COULD LEAD TO SOME SEVERE HAIL IF
STORMS DEVELOP. ADDITIONALLY, WHILE AN OUTSIDE POSSIBILITY (<10%) AT
THIS TIME GIVEN EXPECTED SKY COVER AND MORNING SHOWERS DELAYING IF
NOT OUTRIGHT PREVENTING SURFACE DESTABILIZATION, IF STORMS CAN
BECOME SURFACE BASED, A TORNADO RISK WOULD BE PRESENT GIVEN SFC-500M
SRH VALUES UPWARD OF 150 M2/S2.
AVIATION /12Z TAFS THROUGH 12Z FRIDAY/
ISSUED AT 523 AM CST THU MAR 5 2026
IFR TO LOW-VFR CONDITIONS ARE EXPECTED TO BEGIN THE TAF PERIOD WITH
A COMBINATION OF LOW-LEVEL STRATUS AND PATCHY FOG BEING PRESENT
ACROSS THE LOCAL AREA. WHILE VSBY REDUCTIONS ARE EXPECTED TO IMPROVE
BY MID-MORNING AS SHALLOW LOW-LEVEL MIXING OCCURS AFTER DAYBREAK, A
LOW-LEVEL INVERSION ALOFT SHOULD KEEP LOW-LEVEL MOISTURE IN PLACE
WITH THE HREF/NBH HAVING HIGH PROBABILITIES (60-90%) FOR MVFR CIGS
THROUGHOUT THE DAYTIME HOURS. AS OUR NEXT WEATHER DISTURBANCE MOVES
INTO THE REGION, CIGS WILL LIKELY DROP TO IFR HEIGHTS WITH SHOWERS
AND EMBEDDED STORMS MOVING INTO PORTIONS OF SOUTHEAST MN AND
NORTHEAST IA BY AROUND 09Z FRIDAY. CONSEQUENTLY, EXPECTING VSBYS TO
DROP TO MVFR/IFR LEVELS WITHIN SHOWERS AND THUNDERSTORMS.
ARX WATCHES/WARNINGS/ADVISORIES
WI...NONE.
MN...NONE.
IA...NONE.
DISCUSSION...FERGUSON
AVIATION...NAYLOR
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