652
FXUS63 KOAX 181747
AFDOAX
AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE OMAHA/VALLEY NE
1247 PM CDT MON MAY 18 2026
KEY MESSAGES
- POTENTIAL FOR MORE SEVERE WEATHER TODAY, MAINLY ACROSS
SOUTHEAST NEBRASKA AND SOUTHWEST IOWA. LARGE HAIL, DAMAGING
WINDS, STRONG TORNADOES, AND FLASH FLOODING WILL ALL BE
POSSIBLE.
- COOLER WEATHER MOVES IN ON TUESDAY WITH POTENTIAL FOR MORNING
FROST FOR NORTHEAST NEBRASKA ON WEDNESDAY.
- ANOTHER ACTIVE PATTERN MAY SET UP GOING INTO NEXT WEEKEND WITH
CHANCES FOR MORE STORMS, AND POSSIBLY SEVERE WEATHER.
DISCUSSION
ISSUED AT 1155 PM CDT SUN MAY 17 2026
TODAY AND TONIGHT...
WE HAD A DECEIVINGLY COOL, CLOUDY START TO THE DAY. TEMPERATURES
THIS MORNING STARTED OFF IN THE 50S AT 9 AM, AND DIPPED INTO THE
UPPER 40S OVER NORTHEAST NEBRASKA. FARTHER SOUTH, HOWEVER, FALLS
CITY HAD ALREADY WARMED TO 70 DEGREES, ON THE WARM SIDE OF A COLD
FRONT DRAPED FROM BEATRICE, TO OFFUTT AFB, TOWARDS SHELBY, IA.
SPOTTY SHOWERS AND A FEW RUMBLES OF THUNDER DEVELOPED BEHIND THE
BOUNDARY THIS MORNING. A STRONG SHORTWAVE TROUGH WILL CONTINUE TO
EJECT EASTWARD THIS AFTERNOON, BRINGING FORCING FOR LARGE-SCALE
ASCENT. DESPITE THE LINGERING CLOUD COVER, VERY STEEP LAPSE RATES
ALOFT AND DAYTIME HEATING OF A MOIST LOW-LEVEL AIRMASS WILL LIKELY
SUPPORT STRONG INSTABILITY SOUTH OF THE COLD FRONT. MESOANALYSIS
DEPICTING STRONG THETAE ADVECTION FROM CENTRAL KANSAS THROUGH
SOUTHEAST NEBRASKA AND SOUTHWEST IOWA DEPICTED THE ABRUPT RESURGENCE
OF A VOLATILE AIRMASS. STORMS HAVE ALREADY BEGUN TO FIRE ON THE WARM
SIDE OF THE BOUNDARY OVER NORTHWEST KANSAS, AND ARE EXPECTED TO
DEVELOP OVER FAR SOUTHEAST NEBRASKA BY 2 PM THIS AFTERNOON. INITIAL
ISOLATED SUPERCELLS WILL HAVE THE GREATEST POTENTIAL FOR PRODUCING
STRONG, POTENTIALLY VIOLENT TORNADOES, VERY LARGE HAIL, AND DAMAGING
WINDS, WITH THE GREATEST RISK IN FAR SOUTHEAST NEBRASKA. BY 4 OR 5
PM, CAMS DEPICT MORE WIDESPREAD CLUSTERS OF STORMS DEVELOPING, WITH
THE POTENTIAL FOR SUPERCELL STRUCTURES. WHILE NOT AS EXTREME AS THE
POSSIBLE INTENSITY OVER FAR SOUTHEAST NEBRASKA, THESE STORMS,
PRIMARILY ALONG AND SOUTHEAST OF A LINE FROM LINCOLN TO OMAHA WILL
STILL BE CAPABLE OF PRODUCING LARGE HAIL, DAMAGING WINDS, AND
PERHAPS A TORNADO OR TWO.
IN ADDITION TO HAIL, WINDS, AND A CHANCE FOR TORNADOES, HEAVY RAIN
WILL ALSO BECOME AN ISSUE OVERNIGHT. LAST NIGHT'S ROUND OF
CONVECTION BROUGHT AROUND 0.5" TO 1" OF RAIN ACROSS THE FORECAST
AREA. THE POTENTIAL FOR A FEW TRAINING STORMS WITH 3"+ PER HOUR
RATES ON TOP OF THE ALREADY SATURATED SOILS WILL CREATE THE
POTENTIAL FOR FLASH FLOODING ACROSS PARTS OF FAR SOUTHEAST NEBRASKA
AND SOUTHWEST IOWA TONIGHT. THEREFORE, A FLOOD WATCH REMAINS IN
EFFECT UNTIL 7 AM TUESDAY FOR SOUTHEAST NEBRASKA AND PARTS OF
SOUTHWEST IOWA.
TUESDAY AND BEYOND...
WE'LL SEE THE COLD FRONT CLEAR WELL TO THE SOUTH AND EAST OF OUR
AREA BY TUESDAY, PUTTING A COOLER CANADIAN AIR MASS IN PLACE
ACROSS THE REGION. TUESDAY WILL START OUT CLOUDY ONCE AGAIN, BUT
REALLY CLEAR BY THE AFTERNOON AS HIGH PRESSURE BUILDS OVER OUR
AREA. HIGH TEMPERATURES ON TUESDAY WILL ONLY REACH INTO THE
UPPER 50S TO MID 60S. WITH CLEAR SKIES AND NEARLY CALM WINDS,
THIS LENDS TO POTENTIAL FOR FROST EARLY WEDNESDAY. OVERNIGHT
LOWS WILL DROP INTO THE MID 30S FOR NORTHEAST NEBRASKA TO LOW
40S ACROSS SOUTHEAST NEBRASKA AND SOUTHWEST IOWA. COOLER WEATHER
HOLDS INTO WEDNESDAY THOUGH WE DO SEE A REVERSAL TO SOUTHERLY
WINDS AND START TO ADVECT MOISTURE BACK INTO THE REGION. AN
UPPER-LEVEL SHORTWAVE COULD POTENTIALLY BRING A FEW SHOWERS TO
THE AREA WEDNESDAY AFTERNOON AND EVENING, BUT THE ENSEMBLES
HAVEN'T PICKED UP ON THIS LATEST CHANGE IN THE DETERMINISTIC
GUIDANCE. IN ANY CASE, THIS WOULDN'T BE ANYTHING IMPACTFUL.
A BETTER CHANCE FOR SHOWERS AND STORMS MOVES IN THURSDAY AS THE
LONGWAVE TROUGH THAT'S BEEN NEARLY STATIONARY OVER THE WESTERN
US SHIFTS EASTWARD TOWARD OUR AREA. WITH TEMPERATURES STILL IN
THE SIXTIES FOR HIGHS, I WOULDN'T ANTICIPATE MUCH OF A SEVERE
WEATHER THREAT WITH THIS SYSTEM FOR OUR AREA.
TEMPERATURES START TO REBOUND ON FRIDAY THOUGH AS WE SEE
ENHANCED WARM AIR ADVECTION AHEAD OF A DEEPENING SURFACE LOW
WHICH DEVELOPS ON THE LEE SIDE OF THE ROCKIES OVER EASTERN
COLORADO AND WESTERN NEBRASKA. DEPENDING ON THE TRACK OF THIS
SYSTEM, WE COULD POTENTIALLY SEE MORE ACTIVE WEATHER NEXT
WEEKEND WITH SEVERAL CHANCES FOR STORMS.
AVIATION /18Z TAFS THROUGH 18Z TUESDAY/
ISSUED AT 1244 PM CDT MON MAY 18 2026
WIDESPREAD IFR/MVFR CEILINGS ARE OBSERVED ACROSS TERMINALS THIS
AFTERNOON. WILL SEE AN AREA OF SCATTERED SHOWERS AND STORMS
OVERSPREAD KLNK AND KOMA AFTER 21Z. HAVE REFINED TIMING A BIT WITH
THIS ISSUANCE, BUT EXPECT FURTHER REFINEMENTS AND ADJUSTMENTS.
STORMS THAT AFFECT TERMINALS WILL LIKELY BECOME SEVERE WITH STRONG
WINDS, VERY LARGE HAIL, AND THE POTENTIAL FOR A TORNADO. HAVE ADDED
A TRANSITION TO -SHRA AT KOMA AND KLNK AFTER 01/02Z. CEILINGS WILL
BOUNCE BETWEEN MVFR/IFR OVERNIGHT, BEFORE LARGELY BECOMING MVFR LATE
IN THE TAF PERIOD. WINDS FROM THE NORTH NORTHEAST WILL TURN TO THE
NORTH NORTHWEST THIS EVENING, WITH GUSTS GRADUALLY INCREASING TO 25
TO 30 KTS, PERSISTING FOR THE REST OF THE TAF CYCLE.
OAX WATCHES/WARNINGS/ADVISORIES
NE...FLOOD WATCH THROUGH TUESDAY MORNING FOR NEZ065-066-068-078-
088>093.
IA...FLOOD WATCH THROUGH TUESDAY MORNING FOR IAZ090-091.
DISCUSSION...KG/MCCOY
AVIATION...CASTILLO
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