820
FXUS63 KOAX 161935
AFDOAX
AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE OMAHA/VALLEY NE
235 PM CDT THU JUL 16 2026
KEY MESSAGES
- ISOLATED SHOWERS, EVEN ONE OR TWO THUNDERSTORMS WILL BE
POSSIBLE THIS AFTERNOON.
- HEAT BUILDS INTO THE WEEKEND, WITH HEAT INDEX VALUES NEAR 100
TO 105 AT TIMES FROM FRIDAY THROUGH MONDAY.HEAT INDEX RISING
ABOVE 105 ALONG THE NEBRASKA- SOUTH DAKOTA BORDER. ACTUAL
TEMPERATURES AROUND 100 FOR MONDAY.
- COOLER TEMPERATURES TUESDAY THROUGH THURSDAY, DROPPING BACK
INTO THE 80S AND 90S.
- 15-30% CHANCE OF THUNDERSTORMS IN NORTHEAST NEBRASKA ON SUNDAY
NIGHT, THEN DRY CONDITIONS UNTIL THURSDAY, WHEN SHOWER AND
THUNDERSTORMS CHANCES INCRASE TO 30-40%.
DISCUSSION
ISSUED AT 235 PM CDT THU JUL 16 2026
TODAY AND TONIGHT...
THE LATEST SATELLITE IMAGERY HAS A MORE ROBUST CUMULUS FIELD
TODAY, AS A LOW LEVEL STREAM OF GREATER THETA-E AIR ADVECTS FROM
THE LOWER MISSISIPPI VALLEY. DIABATIC HEATING AND MIXING IS
TAPPING INTO LOW-MID LEVEL INSTABILITY, WHICH IS FURTHER
AMPLIFIED BY A WEAK, MESO-SCALE (?) SWIRL LOCATED OVER NORTHEAST
COLORADO UNDERCUTTING THE LARGER UPPER LEVEL RIDGE. THE RESULT
ARE ISOLATED SHOWERS POPPING UP WHERE LOCAL THERMODYNAMIC
FORCING IS THE BEST. ANY SHOWERS/SPRINKES WILL DISSIPATE WITH
THE SETTING SUN. UNDER CLEAR SKIES, TONIGHT WILL BE A LITTLE
MUGGIER WITH INCREASING DEWPOINTS, WITH LOWS IN THE LOWER TO
MIDDLE 70S IN MOST LOCATIONS.
FRIDAY AND SATURDAY...
EXPECT 2-5 DEGREE BUMP IN TEMPERATURES FOR FRIDAY, WITH H8
THERMAL RIDGE ORIENTED FROM NORTHEAST COLORADO INTO WESTERN
MINNESOTA, AHEAD OF A WEAK FRONTAL BOUNDARY. COMPRESSIONAL
HEATING AND MIXING WILL ALLOW TEMPERATURES TO RISE INTO THE LOW
100S ALONG THE NE-SD BORDER, WITH LOWER TO MIDDLE 90S ELSEWHERE.
THERE'S A 45-50% CHANCE OF A HEAT ADIVSORY BEING HOISTED FOR
COUNTIES ALONG THE NEBRASKA-SOUTH DAKOTA BORDER FOR FRIDAY. THE
BOUNDARY MOVES INTO NORTHERN NEBRASKA AND IOWA FOR SATURDAY,
BRINGING MINOR COOLING NORTH THE BOUNDARY, BUT THE LOW-LEVEL AND
H8 THERMAL RIDGE THEN ORIENTS SOUTH OF THIS BOUNDARY. THERMAL
MIXING WILL NOT BE AS EFFICIENT SURFACE-H8 WINDS BECOMING MORE
SOUTHEASTERLY, THUS TEMPERATURES ABOUT THE SAME OR EVEN A DEGREE
OR TWO COOLER, WITH HEAT INDICES IN THE 94-104 RANGE.
SUNDAY AND MONDAY...
THESE DAYS CONTINUE TO LOOK THE HOTTEST. THE LOW LEVEL THERMAL
RIDGE REMAINS IN PLACE, AND SIMULTANEOUSLY H5 HEIGHTS INCREASE.
LOW-LEVEL FLOW VEERS TO MORE SOUTHERLY ON SUNDAY, AND MORE
SOUTHWESTERLY ON MONDAY. ENSEMBLE EXTREME FORECAST TABLES
DENOTING TEMPERATURES IN THE 90-95% PERCENTILE, WITH SHIFT OF
TAILS OF 1,FOR FOR THE MAXIMUM TEMPERATURES BOTH DAYS, AND THE
MINIMUM TEMPERATURE FOR MONDAY MORNING. SO, WHAT DOES THIS MEAN,
A MORE EXTREME EVENT THAN 30 YEAR CLIMATE RECORD. WE'RE STILL A
4-5 DAYS OUT, BUT AT TIME THERE IS A GREATER PROBABILITY OF
AREAWIDE HEAT HEADLINES FOR THESE DAYS.
THE FLY IN THE OINTMENT FOR MONDAY WILL BE THE EXPANSE OF
NOCTURNAL CONVECTION SUNDAY NIGHT INTO EARLY MONDAY. A MID-
LEVEL SHORTWAVE MOVES ACROSS THE NORTHERN U.S./SOUTHERN CP
PLAINS IN TANDEM WITH A PRONOUNCED JET STREAK WITH H7
TEMPERATURES AT OR ABOVE 12C AND H5 TEMPERATURES 0-5C, IT WILL
BE RATHER WARM FOR ANY HAIL DEVELOPMENT, THOUGH COLLAPSING
STORMS WOULD HAVE WIND POTENTIAL.
TUESDAY THROUGH THURSDAY...
RELIEF FORM THE HEAT COMES AS H5 RIDGE FLATTENS IN THE WAKE OF
THE AFOREMENTIONED SHORTWAVE/JET STREAK COMBO, DRIVING A COOLER
FRONT INTO SOUTHERN KANSAS. THIS WILL REDUCE TEMPERATURES ABOUT
5 DEGREES FOR TUESDAY, WITH FURTHER COOLING WEDNESDAY AND
THURSDAY WITH MORE EARNEST SURFACE TO H8 CAA. WE MAY SEE
NOCTURNAL CONVECTION WEDNESDAY NIGHT INTO THURSDAY, AS STORMS
DEVELOP IN THE LEE OF THE SOUTHERN ROCKIES AND THEN ARE PULLED
EASTWARD BY A WEAK SHORTWAVE MOVING THROUGH THE FLATTENED H5
RIDGE.
AVIATION /18Z TAFS THROUGH 18Z FRIDAY/
ISSUED AT 1259 PM CDT THU JUL 16 2026
ISOLATED SHOWERS ARE POPPING UP AT TAF TIME, AS A GOOD STREAM OF
GREATER THETA-E AIR STREAMS INTO THE REGION. DIABATIC HEATING
AND MIXING ARE THE LOCAL FORCING MECHANISMS, WITH CONTINUATION
THROUGH AFTERNOON WITH A WEAK SWIRL ADVECTING THROUGH THE
ANTICYCLONIC SHEAR SIDE OF LARGER UPPER RIDGE. A FEW OF THE CAMS
HAVE LATCHED ONTO THE DEVELOPMENT. I DIDN'T ADD VICINITY OR
PREVAILING -SHRA OR -TSRA AT ANY OF THE TAF SITES FOR NOW. CLOUD
BASES AT FL040-060 THROUGH 17/01-02 UTC.
WITH SETTING SUN, CU AND AC WILL DISSIPATE, LEAVING MOSTLY CLEAR
SKIES OVERNIGHT. HIGHER LEVEL CLOUDS ARE EXPECTED BY 17/10-12
UTC AT OR ABOVE FL120.
OAX WATCHES/WARNINGS/ADVISORIES
NE...NONE.
IA...NONE.
DISCUSSION...FORTIN/WOOD
AVIATION...FORTIN
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