470
FXUS63 KARX 012222
AFDARX
AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE LA CROSSE WI
520 PM CDT SAT APR 1 2023
DISCUSSION
(THIS EVENING THROUGH SATURDAY)
ISSUED AT 239 PM CDT SAT APR 1 2023
KEY MESSAGES:
- SYSTEM PASSING BY TO THE NORTH SUNDAY COULD BRING A LITTLE BIT
OF RAIN OR SNOW TO PARTS OF NORTH-CENTRAL WISCONSIN.
- ANOTHER POTENT EARLY SPRING SYSTEM LOOKS TO IMPACT THE REGION
EARLY NEXT WEEK WITH ANOTHER ROUND OF RAIN, SOME SNOW, WIND AND
POSSIBLY SOME SEVERE WEATHER. TUESDAY LOOKS TO BE THE MAIN DAY
OF CONCERN, ESPECIALLY IN TERMS OF A SEVERE THREAT.
TONIGHT - SUNDAY...
INCREASED SURFACE WIND GUSTS CONTINUE INTO THE EARLY EVENING FOR
MUCH OF THE FORECAST AREA AS THE UPPER LEVEL TROUGH, EVIDENT ON
GOES WV IMAGERY, CONTINUES EAST INTO THE OHIO RIVER VALLEY. AN
UPPER LEVEL RIDGE, LOCATED OVER THE NORTHERN PLAINS AT 18Z ON GOES
WV IMAGERY, CONTINUES OVER THE FORECAST AREA TONIGHT. RETURN FLOW
WITHIN THESE BUILDING HEIGHTS USHERS IN EXCITED WARM AIR
ADVECTION TONIGHT INTO SUNDAY MORNING. INCREASED WINDS AND
TEMPERATURES WILL BE THE STORY FOR SUNDAY WITHIN THIS TRANSIENT
WARM SECTOR. THE LLJ AT 925 MB PEAKS ABOVE 50 KTS IN SOUTHEAST
MINNESOTA SUNDAY MORNING, DISSIPATING THROUGH THE DAY. SOUTHERLY
TO SOUTHWESTERLY GUSTS TO 40 MPH EXPECTED, PRIMARILY IN WIND PRONE
AREAS WEST THE MISSISSIPPI RIVER. LIGHT, MIXED PRECIPITATION
CHANCES AFFECT CENTRAL WISCONSIN COUNTIES AS AN UPSTREAM JET
STREAK NOSES ACROSS THE NORTHERN PLAINS INTO THE UPPER MISSISSIPPI
RIVER VALLEY SUNDAY AFTERNOON-EVENING. IMPACTS EXPECTED TO BE
MINIMAL.
MONDAY - WEDNESDAY...
THE LATEST SET OF MEDIUM RANGE GUIDANCE CONTINUES TO POINT TO
ANOTHER STRONG SYSTEM TO IMPACT THE UPPER MIDWEST FOR THE FIRST
HALF OF THE NEW WEEK. A SHORT WAVE TROUGH IS EXPECTED TO COME IN
OFF THE NORTHERN PACIFIC AND DROP INTO THE CENTRAL ROCKIES BY
MONDAY NIGHT. THIS SYSTEM THEN EJECTS OUT TO THE NORTHEAST AND
CROSSING THE UPPER MIDWEST TUESDAY NIGHT THROUGH WEDNESDAY. GOOD
CONSENSUS RIGHT NOW THAT THE UPPER LEVEL LOW SHOULD PASS BY THE
THE NORTHWEST OF THE LOCAL AREA. A POTENT SHORT WAVE TROUGH LOOKS
TO BE ROTATING AROUND THE UPPER LEVEL LOW THAT SHOULD BE
APPROACHING THE REGION AND THEN TRACK OVER THE AREA TUESDAY NIGHT.
BOTH THE ECMWF AND GFS KEEP THE SURFACE LOW PRETTY TIGHT TO THE
UPPER LEVEL LOW WHICH ALLOWS IT TO PASS BY TO THE NORTHWEST.
INTERESTING THAT THE 01.12Z CMC HAS COME IN WITH A MUCH FURTHER
EAST TRACK THAT WOULD SUGGEST A MUCH COLDER SOLUTION.
THE LATEST ENSEMBLE DATA HAS REALLY BACKED OFF ON THE POTENTIAL
SNOW IN THE LOCAL AREA FROM THIS SYSTEM, WHICH MAKES SENSE GIVEN
THE EXPECTED TRACK. HOWEVER, SOME SNOW MAY STILL OCCUR AS IT LOOKS
LIKE A WARM FRONT WILL DEVELOP MONDAY NIGHT AND THEN TRY TO LIFT
NORTH TUESDAY. THE ECMWF IS THE MOST AGGRESSIVE WITH BLASTING THE
WARM FRONT THROUGH THE AREA WHILE THE GFS WANTS TO HOLD IT BACK
OVER THE AREA. THIS COULD BE A MORE PROBABLE OUTCOME, ESPECIALLY
IF OVERRUNNING RAIN FORMS TO THE NORTH OF THE WARM FRONT AND HELPS
TO REINFORCE THE COLD AIR AND PIN THE FRONT, SIMILAR TO WHAT
HAPPENED FRIDAY. WITH THIS IDEA, THE ENSEMBLES STILL SUGGEST THERE
IS A 30 TO 40 PERCENT CHANCE FOR SOME MEASURABLE SNOW OVER
PORTIONS OF SOUTHEAST MINNESOTA INTO NORTH-CENTRAL WISCONSIN. THE
PROBABILITIES DROP TO 20 PERCENT OR LESS FOR ONE INCH AMOUNTS,
REFLECTING THE OVERALL WARMER SOLUTION.
WITH THE WARMER SOLUTION, THERE DOES LOOK TO BE A SEVERE THREAT
FOR THE LOCAL AREA. WITH THE DIFFERENCES IN WHAT HAPPENS TO THE
WARM FRONT, THE MEAN ENSEMBLE SOLUTIONS WOULD SUGGEST SOME SURFACE
BASED CAPE SPREADING OVER ALL OF THE LOCAL AREA WITH THE HIGHEST
VALUES TUESDAY AFTERNOON ACROSS THE SOUTHERN SECTIONS. THE
DIFFERENCES WITH THE WARM FRONT CAN BE CLEARLY SEEN IN THE
INDIVIDUAL CAPE FIELDS WITH THE CMC MEMBERS KEEPING THE CAPE SOUTH
OF THE IOWA/MINNESOTA BORDER, THE GEFS BRINGS IT UP TO ABOUT
INTERSTATE 90 WITH THE EPS GOING ALL THE WAY TO LAKE SUPERIOR. THE
SEVERE OUTLOOKS ARE HAVING BEEN PICKING UP ON THE SIGNAL FOR A
POTENTIAL OUTBREAK FOR A COUPLE OF DAYS NOW WITH THE LATEST
OUTLOOKS SHOWING AN INCREASE IN THE POTENTIAL ALONG WITH A BIT OF
A NORTHWARD SHIFT. THE CSU ML OUTLOOKS BASED OFF THE GEFS HAS AT
LEAST A 15% PROBABILITY WHERE IT HAS THE SURFACE CAPE AND 30%
PERCENT PROBABILITIES SOUTH OF INTERSTATE 90. THE INCREASE IN
PROBABILITIES IS SHOWN NOT FAR TO THE SOUTH OF THE AREA WHERE AN
AREA OF UP TO 60 PERCENT RESIDES OVER SOUTHEAST IOWA, ILLINOIS AND
MISSOURI. THE DAY 4 OUTLOOK FROM SPC HAS ALSO SHIFTED A BIT
FARTHER NORTH WITH 15% SHOWN ACROSS NORTHEAST IOWA AND ACROSS
SOUTHERN WISCONSIN WITH THE 30% PROBABILITIES TO THE SOUTH ACROSS
SOUTHERN IOWA INTO ILLINOIS AND MISSOURI. IF THESE TRENDS CONTINUE
WITH LATER MODEL RUNS, WOULD EXPECT TO START SOME MESSAGING ON
THE SEVERE THREAT SUNDAY.
AVIATION
(FOR THE 00Z TAFS THROUGH 00Z SUNDAY EVENING)
ISSUED AT 520 PM CDT SAT APR 1 2023
CIGS: SKC/SCT TONIGHT WITH MID CLOUDS MOVING IN WITH AN UPPER LEVEL
SHORTWAVE TROUGH NEAR 12Z SUN. THE MID/VFR DECK LOOKS TO CLEAR
EARLY/MID AFTERNOON SUN, BUT HIGH CIRRUS COULD LINGER INTO EARLY
EVENING.
WX/VSBY: THE SHORTWAVE TROUGH WILL BRING SOME PCPN WITH IT, BUT NEAR
TERM/MEDIUM RANGE GUIDANCE KEEPS ANY THREAT WELL NORTH OF THE TAF
SITES.
WINDS: BECOMING LIGHT SOUTH/SOUTHEAST THIS EVENING, INCREASING
TOWARD 12Z SUN AND BECOMING FAIRLY BREEZY DURING THE DAY. GUSTS
PUSHING INTO THE LOW 30KTS POSSIBLE AT KRST.
ARX WATCHES/WARNINGS/ADVISORIES
WI...NONE.
MN...NONE.
IA...NONE.
DISCUSSION...04/JAR
AVIATION.....RIECK
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