918
FXUS63 KOAX 041902
AFDOAX
AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE OMAHA/VALLEY NE
202 PM CDT TUE AUG 4 2026
KEY MESSAGES
- RAIN CHANCES SHIFT TO SOUTHEAST NEBRASKA AND SOUTHWEST IOWA
TUESDAY EVENING INTO WEDNESDAY (60-90% CHANCE).
- MILDER TEMPERATURES THROUGH THURSDAY, WARMING BACK UP GOING
INTO THE WEEKEND. DRY, SEASONABLY WARM WEATHER EXPECTED OVER
THE WEEKEND.
- WILDFIRE SMOKE CONTINUES TO DRIFT IN FROM THE NORTH. A SMALL
AMOUNT MAY BE FOUND AT THE SURFACE. MOST WILL BE ELEVATED AND
MAY PRODUCE SOME HAZY SKIES.
DISCUSSION
ISSUED AT 200 PM CDT TUE AUG 4 2026
SURFACE ANALYSIS SHOWS THE COOLER CANADIAN AIR HAS PUSHED
THROUGH ALL BUT THE LAST SOUTHEASTERN COUNTIES OF THE CWA.
BEHIND THE FRONT, TEMPS ARE MOSTLY IN THE 60S AND 70S WITH BRISK
NORTHERLY WINDS. AHEAD OF IT, FALLS CITY, NEBRASKA CITY, AND
SOUTHWEST IOWA HAVE MANAGED 80 BEFORE THE COOLER AIR HAS ARRIVED.
KOAX HAS BEEN INTERPRETING RETURNS FROM RAIN SINCE BEFORE
SUNRISE. RADAR ESTIMATES SUGGEST SOME LOCATIONS BETWEEN NORFOLK
AND SIOUX CITY (INCLUDING WAYNE) HAVE RECEIVED 1.5". GROUND
TRUTH SHOWS GAUGES MOSTLY REPORTING CLOSER TO HALF OF THAT.
THESE SHOWERS AND ASSOCIATED LIGHTNING/THUNDER ARE SLOWLY
SLIDING EAST/SOUTHEAST AND ARE EXPECTED TO DISSIPATE AND PUSH
OUT OF THE SOUTHEASTERN CORNER CWA BY ABOUT 7PM TONIGHT AS THE
SHORTWAVE RESPONSIBLE FOR THEIR FORCING CONTINUES EAST.
THE DRY SPELL WON'T LAST LONG AS ANOTHER VORT MAX - CURRENTLY
OVER THE HIGH COUNTRY OF COLORADO - PUSHES THROUGH OVERNIGHT.
THAT COMBINED WITH THE EXTRA LIFT PROVIDED BY THE SUMMER
NOCTURNAL JET, AND LIKELY POPS (80-90%) ARE EXPECTED IN THE
AREAS WITHIN 50 MILES OF I-80. WITH PWAT VALUES NEAR THE 90TH
PERCENTILE FOR AUGUST, SOME LOCALIZED HEAVY RAIN IS POSSIBLE IN
THE URBAN AREAS OF OMAHA AND LINCOLN. CAM QPF SUGGESTS RAINFALL
OF 3.5" IS POSSIBLE AT OMAHA, WHICH WOULD OVERWHELM THE CITY'S
DRAINAGE SYSTEM. CONSIDERED A FLOOD WATCH, BUT WILL HOLD OFF FOR
NOW DUE TO LOW CONFIDENCE AS TO WHERE THE QPF BULLSEYE IS MOST
LIKELY TO SET UP, BUT WESTERN IOWA/OMAHA METRO HAS BEST ODDS.
THE SPC ADDED AN AREA OF "MARGINAL THREAT" FOR SEVERE WEATHER
THIS EVENING. MOST OF THE LIFT IS DISPLACED NORTH OF THE FRONT,
BUT JUST AHEAD OF IT, THERE IS 1500 J/KG OF CAPE AND 40-50 KNOTS
OF BULK SHEAR. SHOULD A STORM TAP INTO THAT INSTABILITY, IT
COULD PRODUCE SOME BORDERLINE SEVERE WEATHER.
OVERNIGHT'S INSTABILITY WILL BE ELEVATED... LEAVING LOTS OF
THUNDER AND LIGHTNING, BUT LITTLE SEVERE THREAT.
WEDNESDAY
RAINFALL WILL CONTINUE OVER THE SOUTHERN HALF OF THE AREA
THROUGH WEDNESDAY'S FIRST HALF BEFORE CONTINUING SOUTHEAST.
SKIES WILL BE CLEARING FROM NORTH TO SOUTH, BUT THEY'LL REMAIN
MARRED BY THE WILDFIRE SMOKE DRIFTING IN FROM CANADA. EXPECT A
20-30% REDUCTION IN SUNLIGHT. THERE MAY BE SOME SMOKE FOUND AT
THE SURFACE, TOO, BUT MODELS SEEM TO BE OVERDOING IT SO FAR
BASED ON OBSERVATIONS FROM UP NORTH AND I HAVE OPTED NOT TO
INCLUDE IT IN THE FORECAST FOR NOW.
TEMPERATURES WILL BE COOLER FOR WEDNESDAY BEHIND THE FRONT WITH
HIGHS RELEGATED MOSTLY TO THE 70S AS HIGH PRESSURE WORKS IN FROM
THE NORTH.
THURSDAY AND BEYOND
SOUTHERLY RETURN FLOW DEVELOPS AS THE SFC HIGH SLIDES EAST.
THOSE WINDS HELP PUSH TEMPS PAST THE 80F MARK. MORE SHOWERS AND
STORMS ARE POSSIBLE LATE ON THURSDAY NIGHT AS ANOTHER SHORTWAVE
SWEEPS THROUGH KANSAS.
TEMPS WILL CONTINUE TO WARM INTO THE WEEKEND, BUT AS THE H5
PATTERN BECOMES QUASI-ZONAL, TEMPS SHOULD MODERATE TO NEAR
SEASONAL AVERAGES OR A FEW DEGREES WARMER INTO THE LOWER 90S.
AVIATION /18Z TAFS THROUGH 18Z WEDNESDAY/
ISSUED AT 1220 PM CDT TUE AUG 4 2026
LINE OF SHOWERS AND STORMS IN THE NORTHERN HALF OF THE AREA ARE
EXPECTED TO PUSH SOUTHEAST AND OUT OF THE AREA BY 6PM TONIGHT.
THESE SHOWERS AND STORMS WILL BE IMPACTING LNK AND KOMA FROM
ABOUT 00Z TO 02Z THIS EVENING.
MORE CONVECTION IS EXPECTED TO DEVELOP BY 9PM TONIGHT, AND
EXPAND AND SLIDE EAST THROUGH THE OVERNIGHT HOURS. THESE STORMS
SHOULD REMAIN SUB-SEVERE, BUT WILL PRODUCE SOME WIND GUSTS OF
40 MPH OR SO AND LEAVE MVFR CIGS AT KOMA AND PERHAPS KOFK AND
KLNK, TOO.
WILDFIRE SMOKE DRIFTING IN FROM THE NORTH IS MOSTLY ELEVATED AT
5-8,000 FEET, BUT THERE WILL BE SOME AT THE SFC, TOO...
ESPECIALLY ON THE NORTHERN AND WESTERN EDGES OF THE AREA AS THE
TAF PERIOD CONTINUES.
OAX WATCHES/WARNINGS/ADVISORIES
NE...NONE.
IA...NONE.
DISCUSSION...MCCOY
AVIATION...NICOLAISEN
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