Area Forecast Discussion
Issued by NWS Omaha/Valley, NE

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000 FXUS63 KOAX 112315 AFDOAX AREA FORECAST DISCUSSION NATIONAL WEATHER SERVICE OMAHA/VALLEY NE 615 PM CDT FRI JUL 11 2014 .SHORT TERM...(TONIGHT THROUGH MONDAY) ISSUED AT 218 PM CDT FRI JUL 11 2014 MAIN ISSUES CONTINUE TO BE POSSIBLE SEVERE STORMS ALONG WITH PERIODS OF EXCESSIVE RAINFALL. THIS AFTN THROUGH SATURDAY...DISSIPATING CLOUD COVER/AFTN HEATING WILL ALLOW ENVIRONMENT TO QUICKLY DESTABILIZE WITH BOTH NAM/GFS ADVERTISING MUCAPES AROUND 3500 J/KG...LI -1O. THIS IN COMBINATION WITH FAVORABLE EFF SHEAR/DEEP LYR SHEAR PRETTY MUCH SUGGEST INITIAL DEVELOPMENT WILL BE SUPERCELLULAR IN NATURE BEFORE TRANSITIONING TO LARGE CONVECTIVE COMPLEX. THUS SEVERE TSTMS A DISTINCT POSSIBILITY. LIKELY THAT TSTM INITIATION WILL OCCUR SOMEWHERE IN THE VICINITY OF WRN SD/NW NEB WHERE STRONG LLVL MOISTURE ADV WILL BE PERPENDICULAR TO ZONE OF INTENSE BNDRY LYR THETA-E CONVG. CONVECTION WILL INCREASE IN AREAL COVERAGE THEN OVERNIGHT ALONG THE SD/NEB BORDER WHERE LLVL MOISTURE CONVG/STRONG 310K-315K ISENTROPIC UPGLIDE WILL BE FOCUSED. APPEARS THAT WAA FORCING WILL BE MAINTAINED DURING THE OVERNIGHT HOURS WITH 850-250MB DIFF DIVG CONTRIBUTING TO SYNOPTIC SCALE ASCENT. IN ADDITION...PROLONGED RAINFALL EVENT APPEARS PROBABLE MAINLY OVER THE NRN CWA ALONG THE NEARLY STALLED FRONTAL BNDRY. KI VALUES 40-45 INDICATE DEEP LYR MOISTURE WILL BE IN PLACE AT THAT TIME. PRECIP EFFICIENCY WILL BE VERY FAVORABLE CONSIDERING DEPTH OF WARM CLOUD LYR ALONG WITH PWS OF 2" OR MORE. CANNOT DISCOUNT SEVERE TSTM POTENTIAL SAT AFTN WHEN INSTABILITY RAMPS UP AGAIN ALONG SFC BNDRY. CONDITIONS IMPROVING THEN MONDAY AFTN. CONVECTIVE PCPN WILL STILL BE POSSIBLE AT LEAST THRU MONDAY MORNING WHEN A SECONDARY SHOT OF CAA PRESSES SWD INTO THE CNTRL PLAINS. .LONG TERM...(MONDAY NIGHT THROUGH FRIDAY) ISSUED AT 218 PM CDT FRI JUL 11 2014 DETERMINISTIC ECM/GFS AS WELL AS ECMENS/CMCENS AGREE LARGE SCALE PATTERN WILL BE RELATIVELY STAGNANT INTO NEXT WEEK HIGHLY ANOMALOUS CLOSED UPPER LOW ENVELOPING THE ERN CONUS WITH AN UPSTREAM RIDGE OVER THE WRN CONUS. PATTERN WILL BE QUITE FAVORABLE FOR DRY/COOL AIRMASS TO FILTER INTO THE CNTRL PLAINS. THIS AIRMASS WILL BE STRONG ENOUGH TO KEEP MAX/MIN TEMPS BELOW NORMAL THE DURATION OF THE EXTENDED PDS. STILL LOOKS POSSIBLE MORNING LOWS MONDAY AND TUESDAY WILL BE APPROACHING NEAR RECORD VALUES. && .AVIATION...(00Z TAFS FOR KOFK...KLNK AND KOMA.) ISSUED AT 615 PM CDT FRI JUL 11 2014 TSTM CHANCES ARE HIGHEST AT KOFK ACCORDING TO LATEST HRRR MODEL RUNS WHICH KEEP MOST PCPN IN OUR AREA ACROSS NORTHEAST NEBRASKA OVERNIGHT. DID MENTION SOME LOWER CEILINGS AND VSBYS THERE WITH TSRA. FOR KOMA AND KLNK...CHANCES SEEM LOWER AND DID NOT MENTION ANY TSTMS FOR NOW AND EXPECT MAINLY VFR CONDITIONS. SOME FOG IS POSSIBLE TOWARD SUNRISE...SO INCLUDED A TEMPO GROUP FOR THAT. && .OAX WATCHES/WARNINGS/ADVISORIES... NE...NONE. IA...NONE. && $$ SHORT TERM...DEE LONG TERM...DEE AVIATION...MILLER

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