366
FXUS63 KARX 300538
AFDARX
AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE LA CROSSE WI
1238 AM CDT TUE JUN 30 2026
KEY MESSAGES
- DANGEROUS HEAT CONTINUES TUESDAY WITH INDICES 95 - 105+
DEGREES ACROSS THE LOCAL AREA. LOWER CONFIDENCE FOR WEDNESDAY
DEPENDING ON PRECIPITATION CHANCES.
- PERIODIC STORM CHANCES TUESDAY, TUESDAY NIGHT, WEDNESDAY, AND
WEDNESDAY NIGHT. STRONG TO SEVERE STORMS POSSIBLE WEDNESDAY
ALBEIT LOCATION AND STRENGTH REMAIN FORECAST
DISCREPANCY/UNKNOWN.
DISCUSSION
ISSUED AT 1139 PM CDT MON JUN 29 2026
PERSISTENT PATTERN WAVERING CONFIDENCE INTO THE WEEKEND:
THE STRONG SYNOPTIC ANTICYCLONE TOOK SHAPE OVER THE SOUTHEAST
CONUS ON MONDAY WITH MAXIMA TO RECORD 500 MB HEIGHTS IN 30.00Z
ROABS SEEN AT ILX, ILN, RNK, FFC, BMX, JAN, SGF, AND LIX, WHILE
CENTERED OVER OHX. LREF CONFIDENCE REMAINS HIGH (100%) FOR THESE
ANOMALOUS HEIGHTS TO REMAIN CENTERED OVER THE SOUTHEAST THROUGH
MIDWEEK GRADUALLY SHIFTING EAST TO THE MID-ATLANTIC COAST FOR
INDEPENDENCE DAY BEFORE WIDESPREAD INTER/INTRA ENSEMBLE MODEL
DISAGREEMENT. ADDITIONAL, EARLIER INTER-ENSEMBLE DISAGREEMENT
REGARDING THE SYNOPTIC PATTERN ACROSS THE CENTRAL CONUS AFFECTS
LOCAL FORECAST CONFIDENCE THROUGH MIDWEEK.
EXTREME HEAT TUESDAY & STORM CHANCES:
HIGH CONFIDENCE (80%) FOR DAYTIME HIGH TEMPERATURES FROM THE HIGH
80S TO MID 90S FOR TUESDAY, SIMILAR AS MONDAY, WITH LOW TO MID 70
DEGREE SURFACE DEWPOINT TEMPERATURES. LOWER CONFIDENCE IN REBOUNDING
OF INCREASED SURFACE DEWPOINT TEMPERATURES ALONG OUR NORTHWESTERN
PERIPHERY AFTER OVERNIGHT CONVECTION AND AGAIN TUESDAY NIGHT WITH
ADDITIONAL SIMILAR PRECIPITATION CHANCES EXPECTED ALONG WESTERN AND
NORTHERN PERIPHERY. ADDITIONAL, ZONALLY ORIENTED AREA OF STORMS ALSO
POSSIBLE OVERNIGHT INTO WEDNESDAY MORNING DEPENDING ON FRONTAL
BOUNDARY LOCATION IN RELATION TO STRENGTH AND LOCATION OF AREA OF
HIGHER PRESSURE.
LOW-MEDIUM (18-41%) CONFIDENCE WEDNESDAY:
MOST RECENT GEFS (29.18Z) RUN THREW A WRENCH IN MODEL AGREEMENT
THROUGH MIDWEEK BY LIMITING SYNOPTIC FORCING FOR ANY
PRECIPITATION AND STORMS UNLIKE OTHER ENSEMBLES OR ITS PREVIOUS
RUNS. THE RESULTANT SHUNT NORTH OF HIGHER PRECIPITATION AND
STORM POTENTIAL ALONG AND NORTH OF THE FORECAST AREA IS UNLIKE
THE EPS & GEPS WHICH PAINT HIGH (75-100%) PROBABILITIES FOR
MEASURABLE PRECIPITATION ACROSS MUCH OF THE FORECAST AREA
WEDNESDAY AFTERNOON AND NIGHT. HIGHEST AMOUNTS AND PROBABILITIES
SEEN IN THE EPS WITH 80-100% PROBABILITIES FOR 0.5" IN 24 HOURS
ENDING AT 12Z THURSDAY.
STRONG TO SEVERE STORMS POSSIBLE (14%-34%) WEDNESDAY:
STRONG TO SEVERE STORMS REMAIN POSSIBLE ON WEDNESDAY ALBEIT LOW
CONFIDENCE GIVEN THE AFOREMENTIONED SPREAD IN POTENTIAL
SCENARIOS. MACHINE LEARNING SEVERE HAZARD MODELS EXHIBIT THIS
DEPENDENCE ON THEIR PARENT MODELS AS GFS SOLUTION EXHIBITS A
WIDER COVERAGE AND HAZARD THREAT WHILE ECMWF ASSOCIATED MODELS
PAINT THE SOUTHEASTERN HALF OF THE FORECAST AREA WITH 30-45%
PROBABILITIES. WHILE PRIMARY THREAT WOULD BE DAMAGING WINDS, TORNADO
RISK IN LATTER AI MODELS DEPEND ON ABILITY OF CLEARING SKIES
GIVEN ONGOING PRECIPITATION PROBABILITIES. LARGE HAIL WOULD BE
THE LOWER, SECONDARY RISK GIVEN THE VERY WARM ATMOSPHERE
RAISING A MELTING HAIL SIGNAL.
TEMPERATURES THROUGH MIDWEEK:
THEREFORE, THE GEFS SOLUTION IS A FEW DEGREES HIGHER FOR
TEMPERATURES THAN OTHER LREF MEMBERS WITH DAYTIME HIGHS PERSISTING
IN THE LOW 90S FOR WEDNESDAY, POTENTIALLY REQUIRING HEADLINE
ISSUANCES WHEREAS OTHER RUNS AND MODELS ABATE APPARENT
TEMPERATURES INTO HEAT ADVISORY OR LACK THEREOF, DEPENDING ON
CLOUD COVER AND STORM COVERAGE DROPPING DRY BULB TEMPERATURES TO
WET BULB TEMPERATURES. THEREFORE, HAVE ABSTAINED FROM EXTENDING
CURRENT HEADLINES OR RAISING ADDITIONAL HEADLINES THROUGH
MIDWEEK GIVEN THE POTENTIAL /SLIGHT/ REPRIEVE IN MOST EXTREME,
DANGEROUS HEAT INDICES.
AVIATION /06Z TAFS THROUGH 06Z WEDNESDAY/
ISSUED AT 1238 AM CDT TUE JUN 30 2026
DURING THE PAST HOUR, SHOWERS AND ISOLATED STORMS HAVE DEVELOPED
ACROSS NORTHEAST IOWA, SOUTHEAST MINNESOTA, AND WEST-CENTRAL AND
NORTH-CENTRAL WISCONSIN. THIS IS IN RESPONSE TO MOISTURE
CONVERGENCE ASSOCIATED WITH A 40-KNOT 850 MB JET AND UPPER LEVEL
DIVERGENCE ASSOCIATED WITH THE RIGHT ENTRANCE REGION OF A
50-KNOT 300 MB JET. EXPECT THAT THIS PRECIPITATION WILL
GRADUALLY DISSIPATE AND MOVE OUT OF THE AREA IN ABOUT 2 HOURS.
AFTERWARD THE FOCUS WILL BE ON A MCS IN NORTHEAST NEBRASKA. THIS
SHOULD APPROACH THE AREA TOWARD DAY BREAK. CURRENT THINKING IS
THAT IT WILL BE DISSIPATING AS IT APPROACHES AND MOVES
NORTHEAST THROUGH SOUTHEAST MINNESOTA, AND WEST-CENTRAL AND
NORTH-CENTRAL WISCONSIN.
ARX WATCHES/WARNINGS/ADVISORIES
WI...EXTREME HEAT WARNING UNTIL 9 PM CDT THIS EVENING FOR WIZ029-
032>034-041>044-053>055-061.
HEAT ADVISORY UNTIL 9 PM CDT THIS EVENING FOR WIZ017.
MN...EXTREME HEAT WARNING UNTIL 9 PM CDT THIS EVENING FOR MNZ079-
086>088-094>096.
IA...EXTREME HEAT WARNING UNTIL 9 PM CDT THIS EVENING FOR
IAZ008>011-018-019-029-030.
DISCUSSION...JAR
AVIATION...BOYNE
CLICK HERE TO GO TO PREVIOUS BULLETINS.
Main Text Page