357
FXUS63 KOAX 180455
AFDOAX
AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE OMAHA/VALLEY NE
1155 PM CDT SUN MAY 17 2026
KEY MESSAGES
- POTENTIAL FOR MORE SEVERE WEATHER ON MONDAY, 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
THE LINE OF STORMS HAS CLEARED EAST OF THE AREA BUT MUCH OF
SOUTHEAST NEBRASKA AND SOUTHWEST IOWA REMAIN UNDER THE
STRATIFORM RAIN SHIELD WITH SOME EMBEDDED WEAK THUNDERSTORMS.
THIS LIKELY WON'T COMPLETELY CLEAR UNTIL CLOSER TO 7AM MONDAY
MORNING. GOING INTO MONDAY WE'RE GOING TO BE WATCHING TO SEE
WHERE THE COLD FRONT STALLS, WHICH WILL HELP DETERMINE OUR AREA
OF POTENTIAL SEVERE WEATHER MONDAY EVENING.
MONDAY WILL START OUT CLOUDY, WITH SCATTERED LIGHT RAIN SHOWERS
ACROSS MUCH OF THE AREA NORTH AND WEST OF THE COLD FRONT
STALLED ACROSS OUR AREA. THROUGH THE LATE MORNING INTO THE
AFTERNOON WE'LL SEE CLOUDS GRADUALLY CLEAR IN AREAS SOUTH AND
EAST OF THE COLD FRONT. AREAS NORTH OF THE COLD FRONT WILL STAY
CLOUDY. THE UPPER-LEVEL SHORTWAVE ARRIVES, KICKING OFF STORM
INITIATION AROUND 2-4PM. STORMS THAT DEVELOP IN THE WARM SECTOR
WILL HAVE AMPLE INSTABILITY AND SHEAR TO GROW INTO DISCRETE
SUPERCELLS WITH POTENTIAL FOR LARGE HAIL, DAMAGING WINDS, AND
STRONG TORNADOES. EXPECT SIMILAR STORM EVOLUTION, GROWING INTO A
QLCS WITH EMBEDDED SUPERCELLS, WHICH EXITS OUR AREA BY 10PM.
SEVERAL CAMS SHOW A SECOND LINE OF STORMS WHICH DEVELOPS AROUND
8-9PM OVER OUR WESTERN COUNTIES AND MOVES THROUGH POTENTIALLY
BRINGING ANOTHER CHANCE FOR SEVERE HAIL AND DAMAGING WINDS.
THESE STORMS WILL BE ELEVATED IN NATURE, BUT MAY STILL HAVE 1500
J/KG OF ELEVATED MUCAPE TO WORK WITH. THIS SECOND LINE CLEARS BY
MIDNIGHT, BRINGING AN END TO THE LONG, SEVERAL DAY STRETCH OF
SEVERE WEATHER.
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 /00Z TAFS THROUGH 00Z TUESDAY/
ISSUED AT 637 PM CDT SUN MAY 17 2026
A LINE OF SEVERE THUNDERSTORMS IS OBSERVED AT THIS HOUR FROM
NEAR KOFK TO KJYR TO KHJH. THESE STORMS HAVE A HISTORY OF
PRODUCING LARGE HAIL, DAMAGING WINDS, AND TORNADOES. THE LINE
WILL CONTINUE PROGRESSING EASTWARD THIS EVENING, EVENTUALLY
TURNING INTO MORE OF A DAMAGING WIND THREAT AS IT APPROACHES
KOMA AND KLNK. HAVE CONTINUED MENTIONS OF -TSRA AT TERMINALS
THIS EVENING, REFINING TIMING AT KOMA WITH THE LINE EXPECTED TO
ARRIVE BY 01Z PER LATEST MODEL GUIDANCE. EXPECT FREQUENT UPDATES
AND AMENDMENTS. BACKGROUND WINDS WILL SWITCH TO THE WEST
NORTHWEST ONCE THE LINE MOVES THROUGH, AND REMAINING AT 12 KTS
OR LESS AFTER 06Z. CEILINGS WILL DETERIORATE TO MVFR AND IFR AT
TERMINALS TONIGHT BEHIND THE LINE OF STORMS AND PERSIST THROUGH
MUCH OF THE TAF CYCLE. AFTER 20Z, WILL SEE MORE REDEVELOPMENT OF
SHOWERS AND THUNDERSTORMS, WITH CHANCES OVER 50% LATE IN THE
TAF PERIOD. THESE STORMS WILL ONCE AGAIN BECOME STRONG TO SEVERE
WITH ALL HAZARDS POSSIBLE.
OAX WATCHES/WARNINGS/ADVISORIES
NE...FLOOD WATCH THROUGH TUESDAY MORNING FOR NEZ065-066-068-078-
088>093.
IA...NONE.
DISCUSSION...MCCOY
AVIATION...CASTILLO
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