861
FXUS63 KDMX 051133
AFDDMX
AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE DES MOINES IA
633 AM CDT TUE JUL 5 2022
..UPDATED FOR THE 12Z AVIATION DISCUSSION
DISCUSSION
/TODAY THROUGH MONDAY/
ISSUED AT 341 AM CDT TUE JUL 5 2022
TAKE HOME POINTS:
*HOT/HUMID/HEAT HEADLINES CONTINUE TUE, THEN BEGINS TO EASE
*MESSY NEXT 24-36 HRS WITH REGARDS TO STORM CHANCES AND PROGRESSION
*STORM CHANCES/ACTIVE PATTERN CONTINUES THROUGH FRI
DISCUSSION:
OVERNIGHT, HUMID/MUGGY CONDITIONS CONTINUED TO DOMINATE WITH MOST
LOCATIONS ACROSS THE STATE EXPERIENCING LOW TO MID 70S DEW POINTS.
MOISTURE POOLING ALONG/AROUND THE SURFACE ALSO YIELDED DEWPOINTS IN
THE MID TO UPPER 70S FOR PORTIONS OF NORTHERN IOWA OVERNIGHT. THE
FRONT REMAINS ANTICIPATED TO WAVER OVER NORTHERN IOWA TODAY,
RESULTING IN ANOTHER ROUND OF HOT/HUMID/UNCOMFORTABLE CONDITIONS,
THIS TIME FOR MOST OF THE STATE. WITH 850MB TEMPS INTO THE LOW TO
MID 20S DEG C AND DEEP MIXING, HIGHS IN THE MID TO UPPER 90S WILL BE
COMMON. COUPLED WITH THE HUMID CONDITIONS, FORECAST HEAT INDEX
VALUES REMAIN IN/AROUND 105 DEG F, YIELDING THE HEAT ADVISORY FOR
MUCH OF THE STATE TUE. AREAS OF CENTRAL INTO SOUTHERN IOWA WILL
LIKELY BE SPARED FROM THE WORST OF THE HUMID/OPPRESSIVE CONDITIONS
THOUGH WITH SOUNDINGS SUGGESTING DEW POINTS COULD MIX OUT IN TO THE
LOWER 60S DEG F VERSUS THE MID 70S THAT SHOULD REMAIN OVER NORTHERN
IOWA.
STEPPING AWAY FROM THE HEAT, THUNDERSTORM CHANCES, PROGRESSION, AND
SEVERITY POTENTIAL REMAIN IN FLUX AND FAIRLY MESSY. THERE ARE TWO
GENERAL CAMPS/SCENARIOS THAT WERE SEEN WITHIN SYNOPTIC MODEL
GUIDANCE AND THE HI-RES MODELS MONDAY EVENING AND OVERNIGHT. ONE OF
WHICH WAS THUNDERSTORM/MCS DEVELOPMENT OVER EASTERN MONTANA/WESTERN
NORTH DAKOTA THIS MORNING TRACKING DOWN/ALONG AN AREA OF INSTABILITY
TOWARD IOWA. THE OTHER BEING THUNDERSTORM/MCS DEVELOPMENT OVER
WESTERN NEBRASKA/SOUTH DAKOTA THIS AFTERNOON AND AGAIN TRACKING
ALONG AN AREA OF STRONG INSTABILITY. NOTABLY, THE HRRR WAS IN THE
FORMER CAMP FOR A NUMBER OF RUNS THROUGH 00Z TUE ALONG WITH A
SMATTERING OF 12Z/00Z SYNOPTICS, BUT MIGRATED TO THE LATTER CAMP
OVER SINCE THEN. THE 06Z NAM CONTINUES TO HOLD ONTO THE FORMER
SCENARIO. CONCEPTUALLY SPEAKING, BOTH ARE PLAUSIBLE, THOUGH THE
LATTER SCENARIO APPEARS TO BE THE MOST LIKELY, INCLUDING A GROWING
CONSENSUS. REGARDLESS OF STORM/MCS ORIGIN, THE THREATS REMAIN THE
SAME FOR THE AREA WITH DAMAGING WINDS THE MAIN CONCERN. WITH
EXTREME SBCAPE 3000 TO 4000+ J/KG ACROSS NORTHERN IOWA THERE IS
ALSO A CONCERN FOR LARGE HAIL, BUT A PROGRESSIVE MCS MAY LIMIT
THAT POTENTIAL, AT LEAST IN DURATION. ANY ISOLATED CONVECTION IN
ALONG THE SURFACE FRONT/EXTREME CAPE CORRIDOR TOO WILL HAVE THE
CAPABILITY OF LARGE HAIL, BUT WILL STRUGGLE TO ORGANIZE/MAINTAIN
WITH TERRIBLE SHEAR PROFILES. WHILE AREAS IN CENTRAL AND SOUTHERN
IOWA WILL NOT HAVE THE SAME EXTREME INSTABILITY OR HAIL CONCERN,
DEEP INVERTED V PROFILES RAISE CONCERN FOR ENHANCED/DAMAGING
WINDS, AGAIN WHETHER WITH ISOLATED CONVECTION OR ASSOCIATED WITH
AN MCS. THE DAY 1 SPC OUTLOOK DISCUSSES SOME OF THE UNCERTAINTY
AND APPEARS REASONABLE IN HIGHLIGHTING AN AREA OF ENHANCED RISK TO
THE NW WHERE INITIAL STORMS AND MCS DEVELOPMENT MAY BE STRONGEST.
MUCH OF THE REST OF IOWA IS HIGHLIGHTED BY A SLIGHT RISK, WHICH
TOO APPEARS REASONABLE.
THE SURFACE BOUNDARY REMAINS EXPECTED TO BE PUSHED BACK SOUTHWARD
INTO SOUTHERN IOWA/NORTHERN MISSOURI WEDNESDAY BY PREVIOUS
CONVECTION, HELPING FOCUS ADDITIONAL THUNDERSTORM ACTIVITY THROUGH
THE END OF THE WEEK. THE SEVERE THREAT APPEARS LOW WITH LIMITED
POTENTIAL FOR ORGANIZATION, BUT CANNOT BE WHOLLY RULED OUT. THE
GREATER CONCERN AT THIS POINT LOOKS TO TRANSITION TOWARDS HEAVY
RAINFALL AND FLOODING POTENTIAL FROM TRAINING STORM POTENTIAL.
SHOULD COME AS LITTLE SURPRISE, BUT PWATS WILL BE PERSISTENT
AROUND AND IN EXCESS OF 2.00 INCHES. WARM CLOUD LAYER DEPTHS 4000M
TO 5000M ALSO DRIVE HOME THE "TROPICAL" POTENTIAL FOR EFFICIENT
RAINFALL. RAINFALL PLACEMENT AND AMOUNTS TODAY/TONIGHT WILL HELP
DETERMINE AT LEAST INITIAL FLOODING THREAT LOCATIONS THROUGH THE
END OF THE WEEK, SO STAY TUNED IN THAT REGARD.
GENERAL SURFACE HIGH PRESSURE INFLUENCE AND BUILDING UPPER LEVEL
RIDGE WILL QUIET THE PATTERN DOWN OVER THE REGION FOR THE WEEKEND.
THAT DOES APPEAR SHORT LIVED THOUGH WITH RIDGE BREAKDOWN AND
NORTHWEST FLOW RETURNING EARLY NEXT WEEK. HIGH TEMPERATURES AFTER
TODAY WILL SLIDE BACK INTO THE MID TO UPPER 80S MUCH OF THE TIME.
AVIATION
/FOR THE 12Z TAFS THROUGH 12Z WEDNESDAY MORNING/
ISSUED AT 629 AM CDT TUE JUL 5 2022
VFR CONDITIONS WILL PREVAIL TO START OUT THE PERIOD, THEN
ANTICIPATED THUNDERSTORM DEVELOPMENT TOWARD THE LATTER HALF MUDDY
THINGS UP. CONFIDENCE IN LOCATION AND EVOLUTION OF THUNDERSTORM
DEVELOPMENT IS NOT AS HIGH AS ONE WOULD LIKE. HIGHEST CONFIDENCE
RESIDES OVER NORTHERN IOWA AROUND 00Z AT THE MOMENT, THEN
CONFIDENCE ERODES AFTER THAT. DID ATTEMPT TO TIME OUT CURRENT
MOST LIKELY PROGRESSION WITH PERIODS OF PREVAILING TSRA BOUNDED BY
VCTS.
DMX WATCHES/WARNINGS/ADVISORIES
HEAT ADVISORY UNTIL 8 PM CDT THIS EVENING FOR IAZ033-044>046-
057>060-070>074-081>086-092>097.
HEAT ADVISORY FROM NOON TODAY TO 8 PM CDT THIS EVENING FOR
IAZ004>007-015>017-023>028-034>039-047>050-061-062-075.
DISCUSSION...CURTIS
AVIATION...CURTIS
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