790
FXUS63 KOAX 131348
AFDOAX
AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE OMAHA/VALLEY NE
848 AM CDT THU AUG 13 2026
KEY MESSAGES
- RAINFALL RUNOFF HEAVY RAINFALL ACROSS NORTHEAST NEBRASKA AND
THE OMAHA AND COUNCIL BLUFFS METRO AREA WILL LEAD TO
SIGNIFICANT WITHIN BANK RISES IN SEVERAL STREAMS AND RIVERS
TODAY
- ISOLATED STRONG STORMS MAY REDEVELOP LATER THIS AFTERNOON
ACROSS PORTIONS OF WEST CENTRAL IOWA AND SOUTHEAST NEBRASKA. A
BETTER CHANCE OF STRONG TO SEVERE STORMS OCCURS LATE TONIGHT
INTO EARLY FRIDAY.
- PERIODIC SHOWER AND STORM CHANCES CONTINUE THROUGH THE WEEKEND
INTO EARLY NEXT WEEK.
UPDATE
ISSUED AT 0845AM CDT THU AUG 2026
LINGERING SHOWERS AND STORMS FROM AN OVERNIGHT MCS ARE SLOWLY
EXITING THE AREA THIS MORNING. A QUICK LOOK AT AREA RIVERS AND
STREAMS SHOWS SOME LARGE WITHIN BANK RISES IN PORTIONS OF
NORTHEAST NEBRASKA AND THE OMAHA-COUNCIL BLUFFS METRO AREA.
RAINFALL RADAR ESTIMATES INDICATE MAXIMUM RAINFALL AMOUNTS OF
2-4 INCHES IN THESE AREAS.
SKIES WILL GRADUALLY CLEAR DUE TO SUBSIDENCE BEHIND THE MCS SYSTEM
AND MODEST H5 RIDING. A SURFACE FRONTAL SYSTEM ACROSS NORTHERN
KS WILL MOVE NORTHWARD AS A SHORTWAVE MOVES FROM THE SOUTHERN
ROCKIES INTO THE PLAINS. H7 TEMPERATURES OF 15-18C WILL INHIBIT
CONVECTIVE DEVELOPMENT MOST OF THE DAY, BUT A FEW OF THE
SYNOPTIC MODELS AND CAMS TRY TO DEVELOP CONVECTION ALONG THE
PERIPHERY OF THE CAP AS THE LLJ DEVELOPS.
DISCUSSION
ISSUED AT 1215 AM CDT THU AUG 13 2026
RIDGING IS EVIDENT OVER THE SOUTH CENTRAL CONUS ON THIS EVENING'S
WATER VAPOR IMAGERY. OVERSHOOTING TOPS IN WESTERN NEBRASKA ARE
RUNNING -85C. THE KLNX RADAR IS LIT UP WITH SEVERE CONVECTION THAT'S
HEADED THIS WAY. IT'S TIED TO AN UPPER LEVEL SHORTWAVE. UPSCALE
GROWTH HAS BEEN OBSERVED IN THE WESTERN HALF OF NEBRASKA. MODEL
GUIDANCE HAS BEEN CONSISTENT IN KEEPING THE RESULTANT MCV CHUGGING
INTO THE EASTERN PART OF THE STATE AFTER MIDNIGHT TONIGHT AND
BRINGING A SWATH OF DAMAGING WINDS. SOME GUSTS OF 75MPH+ ARE
POSSIBLE (5% AT ANY GIVEN POINT). LARGE HAIL AND A QLCS TYPE TORNADO
CAN'T BE RULED OUT (2%), BUT FLASH FLOODING DUE TO HEAVY RAIN IS
MUCH MORE LIKELY (15%+). GUIDANCE DOES HAVE THE STRONGEST WINDS
TENDING TO FIZZLE OUT BEFORE THE STORMS HIT THE MISSOURI RIVER.
THE WARM FRONT CONTINUES TO LIE ALONG THE KS/NE BORDER AND
ANOTHER LLJ IS RAMPING UP AND TRANSPORTING PLENTY OF MOISTURE
OVER THE COOLER AIR IN PLACE. OUR 00Z BALLOON SHOWED 1.6" OF
PWAT WHICH IS OVER THE 90TH PERCENTILE. WARM CLOUD DEPTHS OF
4,000 METERS MEANS THE RAIN WILL BE EFFICIENT.
THE HREF HAS PROBABILITY OF 3"+ OF RAIN IN THREE HOURS AT
30-50% FOR ALL AREAS NORTH OF THE PLATTE RIVER / I-680. IT'S
CLOSER TO 50-80% FOR 1"+ OF PRECIP IN 3 HOURS. CURRENT FFG
SUGGESTS 2-3" IN THREE HOURS WOULD BE ABOUT ALL SOIL COULD
HANDLE. THANKFULLY, THE SYSTEM LOOKS PROGRESSIVE ENOUGH THAT
THERE WON'T BE MUCH FOR TRAINING / REPEATING ROUNDS OF RAIN.
STILL, I EXPECT A RIBBON OF 3-5" RAINFALL REPORTS.
THURSDAY
THE LAST OF THE STRONGEST STORMS SHOULD BE OUT OF THE AREA BY
8AM ALTHOUGH SOME WRAP AROUND SHOWERS COULD LINGER THROUGH MID-
MORNING AROUND THE SD STATE LINE.
TEMPS WILL HAVE A WIDE RANGE FROM NORTH (77F) TO THE SOUTH (95F)
WHERE DEWPOINTS IN THE 70S WILL PUSH HEAT INDICES PAST THE 100F
MARK. SHOULD THE FORECAST PAN OUT, A HEAT ADVISORY MAY BE
NECESSARY IN THE SOUTHERN TIER OF COUNTIES, BUT CONFIDENCE IS
LOW WITH CONVECTIVE DEBRIS / OUTFLOW AS POSSIBLE FLIES IN THE
OINTMENT.
A 15-20% CHANCE OF THUNDERSTORMS REDEVELOPS IN THE AFTERNOON AS
INSTABILITY PEAKS NEAR 4000 J/KG. CONVECTION IS CONDITIONAL,
MEANING IT'S MOST LIKELY TO NEVER DEVELOP, BUT IF IT IS ABLE TO
BUST THROUGH THE INHIBITION, A SUPERCELL IS POSSIBLE WHICH
SUGGESTS WIND AND HAIL DAMAGE IS POSSIBLE. AGAIN, THIS IS LESS
THAN LIKELY (20%).
BETTER CHANCES OF PRECIP WAIT AGAIN UNTIL AFTER DARK FOR THE
APPROACH OF ANOTHER MCV/MCS THAT ORIGINATES IN THE FRONT RANGE.
WE'LL ALSO WATCH POPS CLIMB AS THE LLJ RAMPS UP AGAIN. THE HREF
SUGGEST RAINFALL RATES WILL BE LESS THAN THOSE OF EARLY THURSDAY
MORNING, BUT SHOULD ANOTHER 2-3" FALL ON TONIGHT'S SOGGIEST
LOCATIONS, FLASH FLOODING WOULD ONCE AGAIN BE AN ISSUE.
FRIDAY AND THE WEEKEND
TEMPS ON FRIDAY AND SATURDAY WILL AGAIN HAVE A 15-20 DEGREE
DISCREPANCY FROM NORTH (70S) TO SOUTH (90S). REGULAR
OPPORTUNITIES FOR SHOWERS REMAIN (40-60% FRIDAY) AND (60-70%)
FOR SATURDAY AS MONSOONAL MOISTURE CONTINUES TO STREAM AROUND
THE HIGH PRESSURE RIDGE OVER TX. POPS PEAK OVERNIGHT THANKS TO
THAT NOCTURNAL SUMMER JET.
SATURDAY NIGHT BRINGS A STRONG COLD FRONT THROUGH THE AREA
LEAVING SUNDAY THE COOLEST DAY OF THE WEEK SO FAR. WITH THE SFC
HIGH SETTLING INTO THE AREA, SKIES WILL CLEAR FROM NORTH TO
SOUTH AND THE DAY SHOULD BE MOSTLY DRY.
BEYOND
GLOBAL MODELS TEND TO DIVERGE IN SOLUTIONS FOR NEXT WEEK WITH
THE EURO BRINGING A TROF THROUGH THE AREA, THE CANADIAN A RIDGE,
AND THE GFS SPLITTING THE DIFFERENCE. WILL KEEP REGULAR 20% POPS
IN THE FORECAST FOR NEXT WEEK, WHICH ISN'T FAR FROM AUGUST
CLIMATOLOGY.
AVIATION /12Z TAFS THROUGH 12Z FRIDAY/
ISSUED AT 715 AM CDT THU AUG 13 2026
RUNNING BEHIND SCHEDULE. ONGOING WEAK CONVECTION ACROSS
PORTIONS OF THE CWA, WITH KOMA BEING THE ONLY TAF SITE STILL
BEING AFFECTED BY IFR/MVFR VISIBILITIES REDUCED DUE TO
THUNDERSTORMS AND SCATTERED TO BROKEN MVFR CEILINGS. EVENTUALLY
WILL SEE THE BACKSIDE OF MCS THAT ROLLED THROUGH THE AREA
OVERNIGHT TO EXIT THE AREA IN THE NEXT 1-2 HOURS. SUBSIDENCE AND
DECREASING LAYER MOISTURE BELOW 700MB SHOULD ALLOW SKIES TO
CLEAR GRADUALLY THROUGH THE MORNING HOURS AT KOMA AND KLNK.
THERE IS A 40-50% CHANCE THAT MVFR CIGS COULD PERSIST BEYOND 14Z
AT KOFK, BUT FOR NOW JUST HAVE A TEMPO GROUP THROUGH 14Z.
THERE IS A LACK IN CONSISTENCY IN TIMING AND LOCATION OF
DEVELOPMENT OF CONVECTION THIS EVENING AND OVERNIGHT ACROSS THE
AREA IN COMPARING THE SYNOPTIC AND CAM. FV3 AND GFS TRY TO LIGHT
UP STORMS ACROSS SOUTHEAST NE (AFFECTING KLNK AND MAYBE KOMA) BY
00Z, BUT THE OTHER SYNOPTIC AND CAMS KEEP A CAP IN PLACE AND
LIMIT DEVELOPMENT UNTIL NOCTURNAL LLJ DEVELOPMENT AFT 06Z.
OAX WATCHES/WARNINGS/ADVISORIES
NE...NONE.
IA...NONE.
DISCUSSION...NICOLAISEN
AVIATION...FORTIN
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