066
FXUS63 KARX 111722
AFDARX
AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE LA CROSSE WI
1222 PM CDT SUN MAY 11 2025
KEY MESSAGES
- ELEVATED FIRE WEATHER CONDITIONS ARE EXPECTED TODAY AND
MONDAY, ESPECIALLY FROM THE I-90 CORRIDOR NORTHWARD. LIMIT
OUTDOOR BURNING.
- LOW END RAIN CHANCES (20-30%) FOR TUESDAY AND WEDNESDAY.
HIGHER THREAT FOR SHOWERS/STORMS MOVES IN THURSDAY INTO FRIDAY
AREAWIDE (40-70%).
DISCUSSION
ISSUED AT 356 AM CDT SUN MAY 11 2025
ELEVATED FIRE WEATHER CONDITIONS TODAY AND MONDAY:
07Z WV SATELLITE REVEALS AN UPPER LOW OVER LA WITH AN UPPER RIDGE
OVER THE FOUR CORNERS TO THE CENTRAL CONUS AND RESULTING
NORTHWESTERLY FLOW ALOFT OVER OUR CWA. AN UPPER WAVE IS SEEN OVER
QUEBEC WITH A SURFACE HIGH BUILDING IN THE WAKE OF THIS FEATURE TO
OUR EAST WITH THIS HIGH CENTERED IN SOUTHERN PORTIONS OF NORTHERN
ONTARIO. END RESULT HAS BEEN LIGHT WINDS IN OUR CWA WITH DEWPOINTS
LARGELY FAILING TO RECOVER.
TODAY, AFOREMENTIONED UPPER RIDGE AXIS SHOULD SHIFT OVERHEAD WITH
RESULTING LARGE SCALE DESCENT LEADING TO MOSTLY CLEAR SKIES. WITH
LEE CYCLOGENESIS OCCURRING IN E MT AND THE ONTARIO SURFACE HIGH
SHIFTING EASTWARD A BIT, INCREASED PRESSURE GRADIENT ACROSS THE AREA
SHOULD LEAD TO AN UPTICK IN WINDS. GIVEN THIS AND CLEAR SKIES,
EFFICIENT MIXING SHOULD HELP TEMPERATURES REACH THEIR FULL POTENTIAL
WITH HIGHS IN THE UPPER 70S AND 80S WHILE DEWPOINTS WILL LIKELY
TREND TOWARD THE LOW END OF THE MODEL DISTRIBUTION. HAVE NUDGED
HIGHS UPWARD AND SHIFTED DEWPOINTS TOWARD THE LOW END OF CONSENSUS
BLENDS ACCORDINGLY. THIS WILL RESULT IN ELEVATED FIRE WEATHER
CONDITIONS IN MANY LOCATIONS, PARTICULARLY ALONG AND NORTH OF I-90.
FOR MORE, SEE THE FIRE WEATHER SECTION BELOW.
RAIN CHANCES TUESDAY AND WEDNESDAY. POTENTIAL THUNDERSTORMS THURSDAY
INTO FRIDAY:
WHILE THE UPPER RIDGE LOOKS TO REMAIN OVER THE REGION IN SOME FORM
THROUGH THURSDAY, CLOSE PROXIMITY OF THE UPPER LOW AS IT SHIFTS
NORTHEASTWARD OVER THE OH VALLEY COULD LEAD TO A SHOWER OR
THUNDERSTORM TUESDAY AND WEDNESDAY AS SHORTWAVES EJECT NORTHWEST.
LIMITING FACTOR LOOKS TO BE INSUFFICIENT MOISTURE FOR PARCELS TO
OVERCOME RELATIVELY WARM AIR IN THE 800-600MB LAYER, AS ILLUSTRATED
BY PROGGED SOUNDINGS IN THE 11.00Z GFS. THUS, POPS TUESDAY AND
WEDNESDAY REMAIN 30% OR LESS.
MOVING AHEAD TO THURSDAY INTO FRIDAY, STRONG UPPER LOW LOOKS TO MOVE
OVER THE UPPER MIDWEST. AS THIS OCCURS, NARROW AXIS OF 850MB MOIST
ADVECTION MAY BRING ENOUGH MOISTURE TO THE REGION FOR PARCELS TO
OVERCOME STUBBORN WARM AIR ALOFT. WITH UPPER LEVEL WINDS RAMPING UP
CONSIDERABLY AHEAD OF THE UPPER LOW, SHEAR WOULD BE SUPPORTIVE OF
ORGANIZED CONVECTION. THUS, IF TIMING REMAINS OPPORTUNE - GUIDANCE
CURRENTLY SUGGESTS MOISTURE WILL ARRIVE JUST IN TIME DURING THURSDAY
AFTERNOON - COULD GET STRONG TO SEVERE THUNDERSTORMS CAPABLE OF ALL
HAZARDS. STILL PLENTY OF TIME TO GO AND PLENTY OF REMAINING
UNCERTAINTY, LARGELY SURROUNDING QUALITY OF THE LOW LEVEL MOIST
ADVECTION GIVEN THE OVERALL PATTERN IS NOT THE MOST FAVORABLE FOR
ROBUST RETURN FLOW. WILL THEREFORE CONTINUE TO TAKE THE CONSERVATIVE
ROUTE WITH REGARDS TO MESSAGING POTENTIAL FOR HAZARDOUS WEATHER
THURSDAY INTO FRIDAY.
AVIATION /18Z TAFS THROUGH 18Z MONDAY/
ISSUED AT 1222 PM CDT SUN MAY 11 2025
VFR CONDITIONS, CLEAR SKIES, AND SOUTHERLY WINDS THROUGH THE
TAF PERIOD. SUSTAINED WINDS MOSTLY RANGING FROM 10 TO 15 KTS.
WIND GUSTS AROUND 20 KTS FOR PORTIONS OF SOUTHEAST MINNESOTA
THIS AFTERNOON. WINDS DECREASE FOR THE OVERNIGHT PERIOD BEFORE
PICKING BACK UP AGAIN MONDAY MORNING.
FIRE WEATHER
ISSUED AT 356 AM CDT SUN MAY 11 2025
CLEAR SKIES AND A STRONGER SURFACE GRADIENT TODAY SHOULD LEAD TO
EFFICIENT MIXING AND, WITH AN INCREASE IN TEMPERATURES ALOFT IN THE
CARDS, WARMER CONDITIONS THIS AFTERNOON. GIVEN EXPECTED EFFICIENT
MIXING, RH VALUES SHOULD PLUMMET BELOW 25 PERCENT ACROSS MUCH OF THE
AREA. THAT SAID, AFOREMENTIONED MIXING SHOULD NOT TAP INTO NOTABLY
HIGHER WINDS ALOFT, RESULTING IN SURFACE WINDS OF 10 TO 20 MPH
TODAY. THUS, CONTINUE TO THINK SOLIDLY ELEVATED CONDITIONS WILL
DEVELOP TODAY AS, WHILE QUITE DRY CONDITIONS ARE EXPECTED, WINDS AND
THEREFORE THE POTENTIAL FOR DIFFICULT TO CONTROL SPREAD LOOK TO BE
LIMITED. FINALLY, OTHER LIMITING FACTOR WILL BE FUELS, AS MANY
SOURCES OF FUEL ARE NOW GREEN GIVEN RAINFALL IN THE RECENT PAST.
HOWEVER, WITH MANY FINE GRASSES STILL CURED, ELEVATED CONDITIONS ARE
STILL EXPECTED WHERE WINDS ARE STRONG ENOUGH - ALONG AND NORTH OF I-
90 WHERE SURFACE GRADIENT IS RELATIVELY STRONGER.
CONTINUED DRY WEATHER AND A LIGHT BREEZE WILL LIKELY LEAD TO
ADDITIONAL ELEVATED FIRE WEATHER CONDITIONS MONDAY, PARTICULARLY IN
SOUTHEASTERN MINNESOTA. ONCE AGAIN, TOP END WIND POTENTIAL APPEARS
TOO LOW AT THIS TIME TO SUPPORT CRITICAL CONDITIONS.
ARX WATCHES/WARNINGS/ADVISORIES
WI...NONE.
MN...NONE.
IA...NONE.
DISCUSSION...FERGUSON
AVIATION...CECAVA
FIRE WEATHER...FERGUSON
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