378
FXUS63 KOAX 291928
AFDOAX
AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE OMAHA/VALLEY NE
228 PM CDT TUE SEP 29 2026
KEY MESSAGES
- WIDESPREAD RAINFALL OF 2 TO 4 INCHES EXPECTED THROUGH
THURSDAY, WITH LOCALLY HIGHER AMOUNTS. A FLOOD WATCH HAS BEEN
ISSUED FOR TUESDAY EVENING THROUGH THURSDAY.
- IF WE GET ANY CLEARING ON WEDNESDAY, A FEW STRONG TO SEVERE
THUNDERSTORMS WILL BE POSSIBLE DURING THE AFTERNOON AND
EVENING, MAINLY IN SOUTHEAST NEBRASKA.
- RAIN WILL END THURSDAY NIGHT, WITH COOLER, DRY CONDITIONS
EXPECTED THROUGH THE WEEKEND.
DISCUSSION
ISSUED AT 226 PM CDT TUE SEP 29 2026
TODAY THROUGH THURSDAY:
WATER VAPOR IMAGERY THIS AFTERNOON FEATURES LARGELY ZONAL FLOW
ACROSS THE NORTHERN HALF OF THE CONUS WITH A POSITIVELY-TILTED
SHORTWAVE TROUGH EXTENDING FROM THE DAKOTAS/NORTHWEST MN SOUTHWEST
TO A CUTOFF LOW OVER THE SOUTHERN GREAT BASIN. THIS CUTOFF
LOW/SHORTWAVE AND THE REMNANTS OF THE FORMER HURRICANE POLO REMAIN
THE FOCUS FOR THE FORECAST PERIOD, WITH STRONG MOISTURE
ADVECTION EXPECTED TO CONTRIBUTE TO EFFICIENT RAINFALL PROCESSES
THAT WILL BE PRESENT THROUGH THE FIRST HALF OF THURSDAY. HIDDEN
IN HIGHER RIVER/FLASH FLOODING THREAT, SEVERE WEATHER WILL ALSO
BE POSSIBLE WEDNESDAY WITH A 5% CHANCE OF DAMAGING HAIL/WIND OR
AN ISOLATED TORNADO NEAR THAT REACHES FROM KANSAS INTO FAR
SOUTH-CENTRAL NEBRASKA.
TAKING A LOOK AT THE SYNOPTIC SETUP FOR THIS PERIOD, THE REMNANT MCV
FROM POLO WILL JOIN THE GREAT BASIN LOW AS THEY EJECT TO THE
NORTHEAST. THIS WILL HELP INITIALLY DEEPEN THE MID/UPPER LOWS, AND
PROMOTE A STRONGER MASS RESPONSE ACROSS THE SOUTHERN AND CENTRAL
PLAINS THAT WILL AMP UP WARM AIR ADVECTION AND MOISTURE
TRANSPORT FROM THE GULF IN ADDITION TO THE REMNANTS FROM POLO.
ALREADY, A COLD FRONT STRETCHES FROM EASTERN ND TO SOUTHEAST CO,
WHILE A WARM FRONT EXTENDS FROM THERE TOWARDS LA. THAT
AFOREMENTIONED COLD FRONT WILL SHIFT INTO THE FORECAST AREA
LATER THIS EVENING, STALLING OUT/BECOMING INCREASINGLY
POSITIVELY-TILTED, AND REMAINING IN THE AREA THROUGH THE FIRST
HALF OF THURSDAY. CONVERGENCE ALONG THE FRONT AS MOISTURE
TRANSPORT RUNS INTO THE FRONTAL INTERFACE ALONG WITH DEEPER LIFT
ASSOCIATED WITH THE LARGE-SCALE HEIGHT FALLS WILL HELP "SKINNY"
CAPE PROFILES TO BE REALIZED AND LEAD TO EFFICIENT RAINFALL
PROCESSES.
LOOKING AT THE PERIODS OF PEAK RAINFALL, THE FIRST WAVE OF HEALTHY
RAINFALL IS SET TO OCCUR THIS OVERNIGHT TONIGHT INTO THE MORNING
HOURS (4 AM TO 10 AM). AFTER A LULL IN ACTIVITY, STRONG CONVERGENCE
IN THE LOWEST LEVELS WILL HELP TO SPREAD STRONGER STORM ACTIVITY
NORTHWARD FROM KANSAS INTO SOUTHERN NEBRASKA AFTER 3 PM TOMORROW.
WE'LL SEE OUR BEST INSTABILITY OF THE FORECAST TO GO ALONG WITH
MODEST SHEAR THAT COULD ORGANIZE SOME OF THE STRONGER STORMS TO
MAKE SEVERE ACTIVITY A POSSIBILITY. THAT MODEST SHEAR AND
CURVATURE IN THE LOW-LEVEL HODOGRAPH WILL KEEP ALL HAZARDS ON
THE TABLE. THOSE SHOWERS AND STORMS PRESENT THE HIGHEST RAINFALL
POTENTIAL AS THE MOVE ACROSS SOUTHEAST NEBRASKA INTO IOWA FROM
3 PM TO 3 AM, AND AMOUNTS DURING THIS TIME COULD EXCEED 2"
ALONE. ONCE THAT PERIOD ENDS, WE'LL BE DEALING WITH EXITING
RAINFALL ACROSS FAR SOUTHEASTERN NEBRASKA INTO SOUTHWEST IOWA
THAT WILL LEAVE US HIGH AND DRY BY THURSDAY NIGHT.
MOST OF SOUTHEAST NEBRASKA ARE SET TO RECEIVE 2-4" OF RAINFALL,
WITH AN NARROW BAND OF 5-6" OR MORE POSSIBLE WHERE THE STRONG
STORMS TRACK WEDNESDAY EVENING. THIS SHOULD TRANSLATE TO AREAS
OF FLASH FLOODING, SEVERAL AREA STREAMS AND RIVERS HITTING
ACTION STAGE, AND A HANDFUL OF LOCATIONS HITTING MINOR FLOOD
STAGES SOUTH OF THE PLATTE RIVER. RIVER LEVELS SHOULD PEAK
FRIDAY AND SATURDAY ACCORDING TO ENSEMBLE RIVER GUIDANCE, AND
COULD COMPLICATE RURAL TRAVEL IF CONDITIONS DO REACH MINOR FLOOD
STAGE.
FRIDAY AND BEYOND:
FRIDAY ONWARD IN THE FORECAST WILL SEE THE AREA DRY OUT
CONSIDERABLY, MUCH TO THE JOY OF THOSE HOPING TO HARVEST. WEST-
NORTHWESTERLY FLOW WILL MOVE INTO THE AREA AND WE'LL SEE
TEMPERATURES HANG IN THE 60S THROUGH THE REMAINING FORECAST THAT
WARMS A TAD BIT TOWARDS THE END OF NEXT WEEK. VERY FEW ENSEMBLE
MODELS OUTPUT ANY QPF FOR EASTERN NEBRASKA AND SOUTHWEST IOWA,
MAKING FOR A WELL-TIMED DRY PERIOD THAT WILL CARRY US INTO
METEOROLOGICAL FALL WITH EXCELLENT WEATHER.
AVIATION /18Z TAFS THROUGH 18Z WEDNESDAY/
ISSUED AT 1225 PM CDT TUE SEP 29 2026
VFR CONDITIONS ARE IN PLACE THIS AFTERNOON ACROSS ALL THREE
TERMINALS, WITH AN INITIAL ROUND OF SHOWERS AND STORMS MOVING
OFF TO THE NORTHEAST OF KOMA, WHILE LIGHTER SHOWERS CONTINUE
NEAR KOFK. AN ADDITIONAL ROUND OF RAIN IS EXPECTED TO DEVELOP
NEAR 21Z NEAR KLNK, SPREADING NORTHEASTWARD DURING THE EARLY
EVENING HOURS WITH A FEW EMBEDDED RUMBLES OF THUNDER THAT ARE
HARD TO PIN DOWN AS WELL (40% CHANCE). AS THOSE SHOWERS PUSH
THROUGH, EXPECT CEILINGS TO FALL INTO MVFR TERRITORY, BEFORE
MOVING INTO IFR TERRITORY OVERNIGHT. LOWER VISIBILITY VALUES
ARE EXPECTED TO DEVELOP AS IFR CONDITIONS ARRIVE, AND KOFK AND
KOMA SHOULD SEE THE WORST OF THEM AT 2SM. WINDS WILL OTHERWISE
TURN SOUTHEASTERLY OVER THE COURSE OF THE TAF, WITH SPEEDS OF
LESS THAN 10 KTS SETTLING IN.
OAX WATCHES/WARNINGS/ADVISORIES
NE...FLOOD WATCH FROM 7 PM CDT THIS EVENING THROUGH THURSDAY
EVENING FOR NEZ015-018-030>034-042>045-050>053-065>068-
078-088>093.
IA...FLOOD WATCH FROM 7 PM CDT THIS EVENING THROUGH THURSDAY
EVENING FOR IAZ043-055-056-069-079-080-090-091.
DISCUSSION...PETERSEN
AVIATION...PETERSEN
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