Area Forecast Discussion
Issued by NWS Omaha/Valley, NE

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000 FXUS63 KOAX 061118 AFDOAX AREA FORECAST DISCUSSION NATIONAL WEATHER SERVICE OMAHA/VALLEY NE 618 AM CDT WED MAY 6 2015 .SHORT TERM...(TODAY THROUGH FRIDAY) ISSUED AT 319 AM CDT WED MAY 6 2015 FORECAST CONCERNS WILL BE TIMING OF SHOWERS/THUNDERSTORMS AND POTENTIAL FOR SEVERE STORMS TONIGHT AND THURSDAY. SHORTWAVE EXTENDING FROM AN UPPER LOW/TROUGH IN NORTHEAST COLORADO INTO CENTRAL OKLAHOMA WILL CONTINUE TO ROTATE NORTHEAST THIS MORNING. AHEAD OF THE TROUGH...WIDESPREAD SHOWERS WERE NOTED ACROSS EASTERN KANSAS...MOVING DIRECTLY TOWARD SOUTHEAST NEBRASKA. SEE NO REASON THIS TREND WILL NOT CONTINUE THIS MORNING...SO EXPECT RAIN TO BECOME WIDESPREAD ACROSS EASTERN NEBRASKA AND SOUTHWEST IOWA EARLY IN THE DAY. THUNDER HAS BEEN ALMOST NON- EXISTENT WITHIN THE LARGER AREA OF SHOWERS GIVEN WEAK INSTABILITY AND SHEAR. EXTRAPOLATION OF RAIN AREA AND MOST MODEL OUTPUT SUGGEST SHOWERS WILL BE LIFTING NORTHEAST OF OUR AREA BY EARLY AFTERNOON...WITH MORE ISOLATED SHOWERS TO FOLLOW. BY MID TO LATE AFTERNOON...ANOTHER SHORTWAVE IS FORECAST TO EMERGE FROM THE HIGH PLAINS AND ENTER CENTRAL NEBRASKA. INSTABILITY AXIS SHOULD REMAIN TO OUR WEST AT THAT TIME...WITH STORMS DEVELOPING ALONG DRYLINE FROM SOUTHWEST NEBRASKA INTO CENTRAL KANSAS. THUS WILL MAINTAIN RELATIVELY LOW RAIN CHANCES THROUGH LATE AFTERNOON AS WE WAIT FOR THOSE STORMS TO PROGRESS EAST OVERNIGHT. TONIGHT...THUNDERSTORMS SHOULD INCREASE IN COVERAGE IN NORTHEAST NEBRASKA CLOSER TO THE NEGATIVELY TILTED TROF. DAYTIME INSTABILITY IS MODERATE ACROSS CENTRAL KANSAS...1000-3000J/KG. THE LOW LEVEL AND H85 FLOW BACKS AND TENDS TO FOCUS THE STRONGER STORMS TO THE WEST OF THE FORECAST AREA FROM SOUTH CENTRAL NEBRASKA AND IN KANSAS. THE INSTABILITY AXIS EXTENDS FROM OKLAHOMA ACROSS KANSAS INTO THE FORECAST AREA THIS EVENING AND OVERNIGHT. AS THE NIGHT PROGRESSES THE STEERING FLOW INCREASES THE THUNDERSTORM COVERAGE ACROSS THE COUNTY FORECAST AREA. CAPE OF 500TO 1500J/KG DOES PUSH INTO THE FORECAST AREA. STRONGER DEEP LAYER SHEAR AT 00Z IS GENERALLY FROM CENTRAL KANSAS INTO SOUTHERN NEBRASKA AT 35-40KTS AND AROUND 25KTS OVERNIGHT. THE ORGANIZED SEVERE WEATHER SHOULD BE WEST OF THE FORECAST AREA...HOWEVER SOME STRONG TO SEVERE STORMS COULD WORK EAST OVERNIGHT. PWATS ARE AROUND 1.5 INCHES BY 06Z AND DID INCLUDE SOME HIGHER QPF AMOUNTS. AMOUNTS COULD VARY FROM 0.25 TO 2 INCHES. WILL MENTION THIS IN THE HWO TOO. RIPPLES IN THE SOUTHWEST FLOW ALOFT CONTINUE FOR THURSDAY WITH THE COLD FRONT PUSHING ACROSS THE FORECAST AREA. THE MOISTURE IS NOT QUITE AS FAVORABLE...HOWEVER THERE IS MODERATE INSTABILITY AND SLIGHTLY BETTER SHEAR PRESENT. THUNDERSTORMS APPEAR LIKELY ALONG THE FRONT...DEVELOPING IN THE AFTERNOON AND CONTINUING OVERNIGHT. SEVERE STORMS MAY DEVELOP IF INSTABILITY IS REALIZED. WITH THE FRONT TO THE SOUTH OF THE FORECAST AREA FRIDAY...SHOULD SEE MAINLY DRY CONDITIONS NORTH...ISOLATED CENTRAL AND CHANCE POPS NEAR THE KANSAS BORDER. .LONG TERM...(FRIDAY NIGHT THROUGH TUESDAY) ISSUED AT 319 AM CDT WED MAY 6 2015 SATURDAY...CLOSED H5 LOW PRES NEAR THE FOUR CORNER AREA WITH NORTHEAST SURFACE FLOW ACROSS THE FORECAST AREA. DRIER FLOW SHOULD LIMIT SHOWERS AND THUNDERSTORMS...HOWEVER THE SURFACE FRONT IS JUST TO THE SOUTH IN KANSAS...SO COULD BE SOME ACTIVITY NEAR THE NEBRASKA SOUTH DAKOTA BORDER. SATURDAY NIGHT THROUGH MONDAY...THE MID TROPOSPHERIC LOW WILL EJECT INTO THE PLAINS. THE TRACK STILL HAS A WIDE RANGE OF SOLUTIONS...AND THIS WILL IMPACT TO LOCATION OF THE HEAVIER RAIN AND POTENTIAL FOR SEVERE STORMS. HIGH POPS SATURDAY NIGHT WITH THE SYNOPTIC LIFT AND STRONG WARM AIR ADVECTION REGIME. THE TRACK OF THE SURFACE LOW VARIES NORTHERN KANSAS TO NORTHERN NEBRASKA SUNDAY INTO SUNDAY NIGHT. THESE DETAILS SHOULD BECOME CLEARER AS WE APPROACH THE WEEKEND. SOME TROF ENERGY COULD LINGER INTO MONDAY...OTHERWISE DRY TUESDAY. HIGHS IN THE 60S AND 70S. && .AVIATION...
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(12Z TAFS FOR KOFK...KLNK AND KOMA.) ISSUED AT 614 AM CDT WED MAY 6 2015 OCCASIONAL SHOWERS WILL AFFECT ALL EASTERN NEBRASKA TAF SITES THIS MORNING...WITH PERIODS OF MVFR CIGS/VSBYS. MOST OF THE ACTIVITY SHOULD BE ENDING BETWEEN 16Z AND 18Z...BUT AN ISOLATED SHOWERS COULD STILL BUBBLE UP AT JUST ABOUT ANY TIME BETWEEN 18Z AND 00Z. OTHERWISE MAINLY VFR CIGS NEAR FL050 AND SOUTHEAST WINDS 15 TO 25KT ARE EXPECTED DURING THAT TIME. A ROUND OF THUNDERSTORMS WILL THEN AFFECT TAF SITES THIS EVENING...DEVELOPING IN CENTRAL NEBRASKA OR KANSAS BY LATE AFTERNOON...THEN ROLLING THROUGH EASTERN NEBRASKA BETWEEN 02Z AND 08Z. MVFR CIGS/VSBYS WILL BE LIKELY NEAR STORMS...BUT BRIEF IFR CONDITIONS ARE POSSIBLE...ALONG WITH WIND GUSTS OVER 30KT.
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&& .OAX WATCHES/WARNINGS/ADVISORIES... NE...NONE. IA...NONE. && $$ SHORT TERM...DERGAN/ZAPOTOCNY LONG TERM...ZAPOTOCNY AVIATION...DERGAN

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