Area Forecast Discussion
Issued by NWS Omaha/Valley, NE

Home | Current Version | Previous Version | Text Only | Print | Product List | Glossary Off
Versions: 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 31 32 33 34 35 36 37 38 39 40 41 42 43 44 45 46 47 48 49 50
-- Highlight Changed Discussion --
-- Discussion containing changed information from previous version are highlighted. --
000 FXUS63 KOAX 221750 AFDOAX AREA FORECAST DISCUSSION NATIONAL WEATHER SERVICE OMAHA/VALLEY NE 1250 PM CDT FRI AUG 22 2014 .UPDATE...
-- Changed Discussion --
ISSUED AT 1236 PM CDT FRI AUG 22 2014 SCATTERED THUNDERSTORMS CONTINUE TO DEVELOP IN NORTHEAST KANSAS AND DRIFT INTO SOUTHEAST NEBRASKA THIS EARLY AFTERNOON IN WEAK MID LEVEL WARM ADVECTION REGIME. THESE WILL CONTINUE TO MEANDER THROUGH THE AREA BUT EXPECT COVERAGE TO GRADUALLY DIMINISH THROUGH THE AFTERNOON AS UPPER RIDGING NOSES SLIGHTLY NORTH AND WARMS MID LEVEL TEMPERATURES. FARTHER NORTH WHERE PLENTY OF SUNSHINE HAS BEEN SEEN...BROKEN CU FIELD HAS DEVELOPED JUST NORTHWEST OF INTERSTATE 80 NEAR STATIONARY FRONT DELINEATED BY LIGHT NORTHEAST WINDS IN NORTHEAST NEBRASKA AND SOUTHEAST WINDS TO THE SOUTH. LAST FEW RAP FORECASTS SUGGEST SOME CONVECTION COULD FIRE LATER THIS AFTERNOON CLOSE TO THIS BOUNDARY...LIKELY FROM THE OMAHA METRO AND WEST...IN AREA WHERE MLCAPES HAVE INCREASED TO NEAR 3500 J/KG. SHEAR IS WEAK HERE...BUT HIGH INSTABILITY COULD LEAD TO STRONG STORMS IF THINGS DO FIRE. OTHERWISE WE ARE STILL EXPECTING INCREASING CHANCES FOR STORMS AS THE EVENING PROGRESSES WITH APPROACH OF STRONG SHORTWAVE ENTERING THE HIGH PLAINS.
-- End Changed Discussion --
&& .SHORT TERM...(TODAY THROUGH SUNDAY) ISSUED AT 341 AM CDT FRI AUG 22 2014 CONVECTIVE ACTIVITY HAS DEVELOPED OVER SWRN IA AND SERN NEB THIS MORNING ALONG A SFC TROF EXTENDING FROM NRN IA TO WRN KS. SIMILAR TO THE LAST SEVERAL NIGHTS...ENVIRONMENT IS QUITE UNSTABLE WITH MUCAPES AROUND 3000 J/KG WITH A STRONG LLVL MOISTURE FEED INTO THE PLAINS. EXPECT ACTIVITY WILL GRADUALLY DIMINISH OVER THE NEXT SEVERAL HOURS AND BE OUT OF THE CWA BY SUNRISE. MOST PRESSING ISSUE FOR THIS FCST PACKAGE IS POTENTIAL SVR TSTMS ALONG WITH HEFTY RAINFALL ANTICIPATED LATER TONIGHT. MODELS HAVE BEEN CONSISTENT LAST SEVERAL RUNS FOCUSING IN ON THE NRN CWA WITH RESPECT TO HIGH POTENTIAL FOR HEAVY NOCTURNAL PCPN LATER TONIGHT. AN OPEN GULF WITH PERSISTENT MOISTURE ADV THRU TODAY WILL ENSURE A MOISTURE RICH ENVIRONMENT WILL BE IN PLACE DURING THE OVERNIGHT HOURS. TODAY...MODELS PROG A POTENT LITTLE VORT MAX EJECTING OUT OF THE BASE OF A DEEP UPPER TROF SITUATED OVER THE WRN CONUS WITH DPVA INDUCING LEESIDE CYCLOGENESIS INVOF THE CNTRL HIGH PLAINS. MODELS AGREE SFC LOW WILL RAPIDLY LIFT TWD THE DAKOTAS THIS AFTN ALONG WITH ATTENDANT WARM FRONT PUSHING INTO THE CWA LATE THIS AFTN. COMBINATION OF STOUT INSTABILITY/EFF SHEAR AND ADEQUATE DEEP LYR SHEAR WITH PROVIDE A FAVORABLE ENVIRONMENT FOR LATE AFTN/EARLY EVENING SUPERCELL DEVELOPMENT. IN ADDITION...VERY HEAVY RAINFALL...MAINLY OVER THE NRN CWA...LOOKS VERY PROBABLE TONIGHT GIVEN COMBINATION OF WARM CLOUD DEPTH AROUND 4500 METERS/SYNOPTIC SCALE MAX OMEGA WILL BE IN PHASE WITH PWS GREATER THAN 2". BEST MOISTURE/FORCING THEN QUICKLY LIFTS NORTH OF THE CWA EARLY SAT MORNING. SAT NIGHT AND SUN...MODELS PROG A SOMEWHAT STRONG COLD FRONT APPROACHING THE CWA. NOT ALL THAT IMPRESSED WITH PCPN POTENTIAL SO WILL OPT FOR TOKEN 20S DURING THOSE PDS. .LONG TERM...(SUNDAY NIGHT THROUGH THURSDAY) ISSUED AT 341 AM CDT FRI AUG 22 2014 COMPARED TO 21/00Z RUN...LATEST ECM IS NOW TRYING TO COME BACK IN LINE WITH GFS/CMC SOLUTIONS SWEEPING A CANADIAN AIR MASS INTO THE NRN/CNTRL PLAINS LATER NEXT WEEK WITH PCPN CHANCES FOCUSED ON FRONTAL BNDRY PASSAGE. GOING POPS LOOK REASONABLE THUS NO MAJOR CHANGES PLANNED. && .AVIATION...
-- Changed Discussion --
(18Z TAFS FOR KOFK...KLNK AND KOMA.) ISSUED AT 1236 PM CDT FRI AUG 22 2014 AREA OF CUMULUS CLOUDS HAD DEVELOPED AT TAF ISSUANCE TIME AND WILL AFFECT ALL TAF SITES THIS AFTERNOON. BROKEN CLOUDS WILL LIKELY REMAIN VFR...BUT SOME FL020 CIGS COULD OCCUR NEAR KOFK FOR A TIME EARLY IN THE AFTERNOON. THEN THE CHANCE FOR SCATTERED CONVECTION WILL INCREASE LATE THIS AFTERNOON...AND ESPECIALLY BY LATE EVENING...AS A STRONG SHORTWAVE LIFTS INTO THE PLAINS. STORMS COULD FIRE AT ANY TIME AFTER 22Z BUT LATEST TRENDS SUGGEST KOMA WILL BE MOST LIKELY SITE TO SEE AFTERNOON AND EARLY EVENING ACTIVITY. OTHERWISE EXPECT CHANCES AND AREAL COVERAGE TO INCREASE BY 05Z AT ALL SITES WITH KOFK THE MOST LIKELY TO SEE OVERNIGHT CONVECTION. ATTENDANT MVFR/IFR CONDITIONS WILL PREVAIL IN ANY STORMS. THUNDERSTORMS SHOULD BE MOVING NORTH OF ALL TAF SITES BY 14Z WITH VFR CONDITIONS AND SOUTHEAST WINDS NEAR 10KT PREVAILING.
-- End Changed Discussion --
&& .OAX WATCHES/WARNINGS/ADVISORIES... NE...NONE. IA...NONE. && $$ UPDATE...DERGAN SHORT TERM...DEE LONG TERM...DEE AVIATION...DERGAN

USA.gov is the U.S. government's official web portal to all federal, state and local government web resources and services.