828
FXUS63 KOAX 111758
AFDOAX
AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE OMAHA/VALLEY NE
1258 PM CDT TUE AUG 11 2026
KEY MESSAGES
- HOT AND HUMID TODAY WITH HEAT INDICES IN THE 95 TO 105 RANGE.
THE HIGHEST INDICES ARE EXPECTED IN SOUTHEAST NEBRASKA AND
FAR SOUTHWEST IOWA.
- LOW CHANCE (15-30%) FOR SOME SCATTERED SHOWERS AND STORMS IN
NORTHEAST NEBRASKA EARLY WEDNESDAY MORNING. A FEW STORMS COULD
BE STRONG WITH GUSTY WINDS.
- WIDESPREAD SHOWERS AND STORMS ARRIVE LATE WEDNESDAY (60-80%
CHANCE) INTO THURSDAY. SOME STORMS COULD BE SEVERE WITH STRONG
WINDS, HAIL, AND HEAVY RAIN.
- PERIODIC SHOWER AND STORM CHANCES CONTINUE THROUGH THE WEEKEND
INTO EARLY NEXT WEEK. COOLER TEMPERATURES ARRIVE BY SUNDAY AND
MONDAY.
DISCUSSION
ISSUED AT 1258 PM CDT TUE AUG 11 2026
SHORT TERM /TODAY THROUGH WEDNESDAY NIGHT/
17Z RAP OBJECTIVE ANALYSIS REVEALS A BROAD H5 RIDGE OVER MUCH
OF THE SOUTHERN CONUS. ACROSS THE NORTHERN THIRD, WESTERLY TO
NORTHWESTERLY FLOW IS OBSERVED WITH SHORTWAVES RIDING THE FLOW.
H7 AND H8 WARM AIR ADVECTION NEAR THE VICINITY OF A BAROCLINIC
ZONE RESULTED IN SOME WEAKLY FORCED SHOWERS AND STORMS ACROSS
FAR SOUTHEAST NEBRASKA INTO SOUTHWEST IOWA THIS MORNING. THE
REMNANT CLOUDS AND OUTFLOW FROM THESE STORMS WILL LIKELY PLAY A
ROLE IN KEEPING HEAT INDICES JUST UNDER ADVISORY CRITERIA.
SHOULD STILL SEE A WARM AND HUMID DAY THOUGH WITH HEAT INDICES
RANGING FROM THE 100 TO 105 RANGE, PRIMARILY ALONG THE KS/NE
BORDER INTO FAR SOUTHWEST IOWA.
AS WE GO INTO THE REST OF THE EVENING AND NIGHTTIME HOURS, WILL SEE
ANOTHER MID LEVEL WAVE TRAVERSE THE NORTHWESTERLY FLOW. FORCING TIED
TO THE WAVE WILL BE STRONGEST OVER THE DAKOTAS NEAR THE LOCATION OF
A SFC TROF/BOUNDARY. CONVECTION DEVELOPS ACROSS THIS AREA, WITH CAMS
TAKING THE ACTIVITY SOUTHEASTERLY INTO THE FORECAST AREA SOMETIME
AFTER 06Z OR 07Z. CAMS SUGGEST A WIDE VARIETY OF OUTCOMES THOUGH,
WITH SOME LIKE THE 12Z NAM 4KM NEST, HIRES ARW, AND FV3 TAKING THE
COMPLEX INTO NORTHEAST NEBRASKA, WHILE THE 12Z HRRR NOTABLY KILLS
OFF THE COMPLEX AS IT REACHES OUR DOORSTEP. FORECAST BUFKIT
SOUNDINGS SHOW MUCH OF THE INSTABILITY (1,500-2,000 J/KG)
ROOTED ALOFT ABOVE 700 MB OR SO WITH CONSIDERABLE LOW LEVEL CIN,
AND WITH WEAK/NEBULOUS FORCING IN THE AREA, CONVECTION WILL
LIKELY WANE/STRUGGLE WITH EASTWARD EXTENT.
IF STORMS CAN SUSTAIN THEMSELVES, THEY COULD BE STRONG TO SEVERE
GIVEN THE INSTABILITY AND MARGINAL SHEAR. THE MAIN HAZARDS WITH
STORMS WILL LIKELY BE STRONG WIND GUSTS. POPS WITH THIS
FORECAST UPDATE REMAIN AT 15 TO 30% FROM 06Z TO 12Z FOR AREAS
NORTHWEST OF A LINE FROM ELGIN TO HARTINGTON.
FOR THE DAYTIME WEDNESDAY, HIGHS ARE PROGGED TO REACH THE 80S TO LOW
90S WHILE THE BAROCLINIC ZONE LINGERS ACROSS THE SOUTHERN HALF OF
THE FORECAST AREA. SOME CAMS BUBBLE UP A FEW SCATTERED SHOWERS AND
STORMS ALONG THE BAROCLINIC ZONE IN THE AFTERNOON, SO HAVE INTRODUCE
SOME LOW 15 TO 20% POPS ALONG OUR FAR SOUTHERN BORDER AREAS. BY
WEDNESDAY EVENING, ANOTHER MIDLEVEL WAVE IS PROGGED TO TRAVERSE THE
PERIPHERY OF THE H5 RIDGE, WITH THE ATTENDANT FORCING FOR
ASCENT COLLOCATED MORE OVER OAX. AMPLE INSTABILITY OF 2,000 TO
3,000 J/KG WITH 25 TO 40 KTS OF BULK SHEAR WILL YIELD A SEVERE
WIND AND HAIL THREAT OVER MOST OF THE AREA.
CAM GUIDANCE DEPICTS TWO PRIMARY AREAS OF CONVECTION THAT DEVELOP:
ONE TIED TO THE MID LEVEL WAVE OVER SD AND ANOTHER AREA CLOSER
TO THE BAROCLINIC ZONE IN CENTRAL NEBRASKA. STORMS EVENTUALLY
CONGEAL INTO AN MCS AS IT PUSHES INTO THE AREA, BUT SOME DETAILS
REMAIN UNCLEAR ON ITS EVOLUTION. A FEW ELEVATED STORMS MAY
DEVELOP AHEAD OF FEATURE TOO WHERE THE H8 LLJ SPEED CONVERGENCE
IS ENHANCED. EFFICIENT RAINFALL IS LIKELY TOO, GIVEN FAVORABLE
WCD TO 4,000-4,500 METERS AND PWATS OF 1.9 TO 2 INCHES. AREAS
WHICH SEE REPEATED PASSAGE OF STORMS COULD LEAD TO A FEW
INSTANCES OF FLASH FLOODING. POPS INCREASE AFTER 05Z TO 60 TO
80% OVER MUCH OF THE FORECAST AREA. NORTHEAST NEBRASKA INTO WEST
CENTRAL IOWA HAS THE BEST CHANCE AT GETTING AN INCH OR MORE OF
PRECIP (50% CHANCE PER LATEST NBM) OUT OF THESE STORMS.
LONG TERM /THURSDAY THROUGH MONDAY/
SHOWERS AND STORMS WILL BE ONGOING THURSDAY MORNING, TAPERING OFF BY
THE AFTERNOON. HIGHS FOR MOST AREAS COOL TO THE UPPER 70S AND 80S,
WITH A FEW SPOTS REACHING 90F ALONG OUR SOUTHERN BORDER. WILL SEE
MORE REDEVELOPMENT OF SHOWERS AND STORMS BY THURSDAY EVENING INTO
FRIDAY (50 TO 80% CHANCE ALONG AND NORTH OF THE PLATTE RIVER) AS
CONTINUED WARM ADVECTION AND ANOTHER MID LEVEL IMPULSE MOVES INTO
THE AREA. SOME SEVERE POTENTIAL EXISTS TOO, LARGELY OVER OUR
SOUTHERN AREA WHERE THE BEST SHEAR AND INSTABILITY OVERLAP.
PERIODIC SHOWER AND STORM CHANCES ARE FORECAST FOR MUCH OF THE
EXTENDED AS THE H5 RIDGE FINALLY PUSHES TOWARD THE SOUTHEAST CONUS,
PLACING US IN SOUTHWESTERLY FLOW WITH SEVERAL DISTURBANCES MOVING
THROUGH. AT THIS TIME, THE BEST CHANCES APPEAR TO BE FRIDAY NIGHT
INTO SATURDAY (30-50%) AND SATURDAY NIGHT INTO SUNDAY (50-70%).
HIGHS FRIDAY AND SATURDAY WARM TO THE 80S/LOW 90S, WHILE BY SUNDAY
AND MONDAY, COOLER TEMPS ARRIVE IN THE MID 70S TO LOW 80S.
AVIATION /18Z TAFS THROUGH 18Z WEDNESDAY/
ISSUED AT 1212 PM CDT TUE AUG 11 2026
VFR CONDITIONS ARE EXPECTED TO PREVAIL FOR THE DURATION OF THE
TAF CYCLE WITH PASSING MID TO HIGH LEVEL CLOUDS. EXPECT WINDS
OF 12 KTS OR LESS AT TERMINALS, TURNING COUNTER-CLOCKWISE BY 12Z
TO THE NORTH NORTHEAST. MODEL GUIDANCE DEVELOPS A FEW SCATTERED
SHOWERS AND STORMS BY 08Z THAT COULD CLIP KOFK (15-20% CHANCE),
BUT CHANCES REMAIN TOO LOW FOR INCLUSION IN TAF AT THIS TIME.
LOW LEVEL WIND SHEAR WILL OVERSPREAD FAR SOUTHEAST NEBRASKA
AFTER 07Z, BUT CONFIDENCE ON THIS REACHING KOMA AND KLNK IS LOW
AT THIS TIME.
OAX WATCHES/WARNINGS/ADVISORIES
NE...NONE.
IA...NONE.
DISCUSSION...CASTILLO
AVIATION...CASTILLO
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