Area Forecast Discussion
Issued by NWS Omaha/Valley, NE

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000 FXUS63 KOAX 260917 AFDOAX AREA FORECAST DISCUSSION NATIONAL WEATHER SERVICE OMAHA/VALLEY NE 417 AM CDT TUE AUG 26 2014 .SHORT TERM...(TODAY THROUGH THURSDAY) ISSUED AT 315 AM CDT TUE AUG 26 2014 ...LOCALLY HEAVY RAIN POSSIBLE THROUGH THURSDAY... THE SHORT TERM FORECAST PROBLEMS CONTINUE TO BE LOCATION OF LOCALLY HEAVY RAIN EACH DAY. THE 00Z OAX SOUNDING HAD A PWAT AROUND 1.4 INCHES AND 1100 J/KG OF ELEVATED INSTABILITY WITH STEEP MID LEVEL LAPSE RATES. THE RADAR WAS FAIRLY QUIET UNTIL AROUND 04Z WHEN STORMS BEGAN TO FIRE AROUND YORK...EXPANDING NORTHEAST TOWARD WAHOO AND FORT CALHOUN. THE LATEST RADAR MOSAIC HAS THE CLUSTER OF STORMS PUSHING EAST AND SOUTHEAST FROM OVER SOUTHEAST NEBRASKA INTO WESTERN IOWA...WITH ADDITIONAL RE-DEVELOPMENT FROM COLUMBUS TO TEKAMAH AND SOLDIER IOWA. THIS UPTICK IN STORMS GENERALLY COINCIDED WITH THE INCREASING LOW LEVEL JET AND RESULTANT DIFFERENTIAL THETA-E ADVECTION ALONG WITH FAVORABLE RIGHT ENTRANCE REGION JET SUPPORT AND MID LEVEL OMEGA. LOCALLY HEAVY 2 TO 4 INCH RAINS PROBABLY FELL IN A NARROW BAND BASED ON RADAR...WITH THE HEAVIEST IN A LINE FROM YORK TO NEAR WESTON...BENNINGTON AND PERSIA IOWA. OTHER GENERAL .5 TO 1.5 INCH AMOUNTS FELL ACROSS PARTS OF THE AREA...WITH NOT MUCH IN FAR NORTHEAST NEBRASKA OR FAR SOUTHERN NEBRASKA SO FAR. THE H5 PATTERN REMAINS FAVORABLE FOR STORM DEVELOPMENT WITH A TROF OVER THE WESTERN U.S. PIECES OF ENERGY EJECT INTO THE PLAINS AND A GENERAL WARM ADVECTION PATTERN WILL REMAIN IN PLACE. THE SURFACE FRONTAL BOUNDARY TO THE SOUTH OF THE FORECAST AREA WILL REMAIN THERE THROUGH WEDNESDAY MORNING THEN MAY TRY TO LIFT NORTH INTO SOUTHEAST NEBRASKA WEDNESDAY AFTERNOON WITH THE BOUNDARY STILL IN THE AREA THURSDAY AFTERNOON. THE MID LEVEL TROF FINALLY MOVES INTO THE CENTRAL PLAINS BY FRIDAY. PWATS ACTUALLY INCREASE TO AROUND 2 INCHES TONIGHT AND REMAIN HIGH THROUGH THURSDAY. WILL MONITOR RADAR TRENDS...BUT EXPECT WITH THE VEERING WINDS THE CLUSTER OF STORMS TO CONTINUE TO PUSH INTO SOUTHWEST IOWA...HOWEVER CONTINUED RE-DEVELOPMENT IS EXPECTED OVER THE FORECAST WITH PERSISTENT WARM AIR ADVECTION...ALBEIT NOT AS FOCUSED. THERE SHOULD BE DECREASING DIURNAL TREND...HOWEVER WARM AIR ADVECTION INCREASES AGAIN BY LATE AFTERNOON AND OMEGA INCREASES SUBSTANTIALLY OVERNIGHT. WE LOOK FOR THE PATTERN TO REPEAT OVER THE NEXT TWO NIGHTS. THE LOW LEVEL JET STRENGTHENS EACH NIGHT AND CONDITIONS ARE FAVORABLE FOR STORMS TO RE-DEVELOP. THE WARM CLOUD DEPTHS REMAIN AROUND 4KM DEEP AND PWATS VERY HIGH. LOCALLY HEAVY RAIN IS LIKELY EACH NIGHT. THE HEAVIEST RAIN MAY ONLY BE A COUNTY OR TWO WIDE AND EXTEND ACROSS PARTS OF THE FORECAST AREA...SO THIS WILL BE TOUGH TO PIN DOWN. THE DIFFERENTIAL THETA-E ADVECTION...MAY BE FARTHER NORTH TONIGHT...SO THIS MAY BE HELPFUL TO SPREAD AROUND THE LOCALLY HEAVY RAIN. WEDNESDAY...AREAS ALONG AND NORTH OF I80 ARE STILL FAVORABLE FOR HEAVY RAIN. THERE IS A STRONG SHORTWAVE AND LIFT OVER THE FRONT IN THE AFTERNOON. THERE IS A SPEED MAX THAT MAY ASSIST IN LIFTING THIS AREA OF HEAVY RAIN NORTH OF THE FORECAST AREA BY THURSDAY MORNING. WHILE HEAVY RAIN WILL BE THE MAIN RISK...DIFFERENTIAL HEATING WILL CONTRIBUTE TO INSTABILITY AND THERE WILL BE SOME DEEP LAYER SHEAR TO WORK WITH...THUS ISOLATED STRONG TO SEVERE STORMS WILL BE POSSIBLE. .LONG TERM...(THURSDAY NIGHT THROUGH MONDAY) ISSUED AT 315 AM CDT TUE AUG 26 2014 PRECIPITATION CHANCES CONTINUE THURSDAY NIGHT...LINGER FRIDAY AND PUSH EAST FRIDAY NIGHT THROUGH SATURDAY. STILL SOME MODEL TIMING DIFFERENCES ON HOW QUICK TO EXIT THE PRECIPITATION WITH THE EC A LITTLE FASTER. SATURDAY NIGHT THROUGH SUNDAY LOOKS MAINLY DRY. ANOTHER TROF OVER THE PACIFIC NORTHWEST AND NORTHERN ROCKIES WILL INCREASE RAIN CHANCES FOR SUNDAY NIGHT DRAGGING A FRONT INTO THE AREA MONDAY. HIGHS SHOULD TOP OUT IN THE 70S AND 80S. && .AVIATION...(06Z TAFS FOR KOFK...KLNK AND KOMA.) ISSUED AT 1126 PM CDT MON AUG 25 2014 SCATTERED THUNDERSTORMS HAD DEVELOPED WEST OF KOMA AND NORTHWEST OF KLNK AROUND 04Z. PERIODS OF THUNDERSTORMS WILL BE LIKELY AT BOTH SITES THROUGH ABOUT 10Z WITH TEMPO MVFR CIGS AND VSBYS. SOME BREAK IN THE CONVECTION INDICATED BY SHORT RANGE MODELS AFTER 12Z AS LOW LEVEL JET WEAKENS WITH VFR CONDITIONS FOR MUCH OF THE REMAINDER OF THE PERIOD. KOFK IS EXPECTED TO BE NORTH OF THE ACTIVITY WITH SOME CHANCE LATE IN THE PERIOD AS BOUNDARY LIFTS FURTHER NORTH. && .OAX WATCHES/WARNINGS/ADVISORIES... NE...NONE. IA...NONE. && $$ SHORT TERM...ZAPOTOCNY LONG TERM...ZAPOTOCNY AVIATION...FOBERT

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