Area Forecast Discussion
Issued by NWS Omaha/Valley, NE

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000 FXUS63 KOAX 190811 AFDOAX AREA FORECAST DISCUSSION NATIONAL WEATHER SERVICE OMAHA/VALLEY NE 311 AM CDT TUE AUG 19 2014 .SHORT TERM...(TODAY THROUGH THURSDAY) ISSUED AT 310 AM CDT TUE AUG 19 2014 WV IMAGERY THIS MORNING SHOWING 2 DISTINCT SHORTWAVE TROFS...ONE OFF THE WEST COAST AND THE OTHER APPROACHING THE WRN GREAT LAKES. MEANWHILE SFC LOW PRESS WAS SITUATED IN MN WITH A FRONTAL BNDRY EXTENDING SW INTO NW KS. CONVECTION ASSOCIATED WITH THE BNDRY OVER NRN KS THIS MORNING WAS GRADUALLY SHIFTING TO THE SE WITHIN AREA OF ISENTROPIC UPGLIDE. LATEST MODELS IN AGREEMENT NRN FLOW WESTERLIES WILL BE PROGRESSIVE THE NEXT SEVERAL DAYS UNTIL LATER THIS WEEK WHEN A UPPER LEVEL HIGH PRESS DOME BECOMING ESTABLISHED OVER THE SERN CONUS. PCPN CHANCES DURING THIS TIME ARE SOMEWHAT PROBLEMATIC...INITIALLY REVOLVING AROUND A MEANDERING SFC BNDRY FOLLOWED BY A WARM FRONT LIFTING THRU THE REGION. FOR TODAY...DAYTIME HEATING COUPLED WITH A MOISTURE RICH ENVIRONMENT WILL PUSH MUCAPES TO 4500J/KG ALONG A NARROW AXIS ALONG THE NEB/KS BORDER AND INTO NRN MO. THE GFS/ECM/CMC ALL SUGGEST CAPPING WILL BE A FACTOR THIS AFTN INHIBITING CONVECTIVE DEVELOPMENT INVOF THE SRN CWA. THE NAM ON THE OTHER HAND PROGS THE CAP BREAKING WITH CONVECTION DEVELOPING. FCST HIGHS THIS AFTN ARE NOWHERE CLOSE TO CONVECTIVE TEMPS...AND TEND TO BELIEVE ANY TSRA THAT DOES DEVELOP WILL BE FOUND SE OF THE CWA WHERE THE GFS/ECM/CMC SHOW CAP WEAKENING. TSTM CHANCES WILL BE BETTER TONIGHT WHEN LLVL JET CRANKS UP WITHIN AREA OF STRONG AGEO LIFT ASSOC WITH MID LYR FRONTOGENESIS. EXPECT INITIATION TO BE CENTERED AROUND STOUT BNDRY LYR THETA-E CONVG AXIS ORIENTED W-E. ON WED...STRENGTHENING LLVL SRLY FLOW OVER THE CNTRL PLAINS IS PROGGED TO PUSH THE SFC BNDRY NWD INTO THE DAKOTAS/MN BY EARLY WED EVENING. THUS BULK OF PCPN ACTIVITY WILL BE FOUND NORTH...BUT CANNOT DISCOUNT SOME TSTMS DEVELOPING OVER THE NRN CWA WED EVENING. THUR NIGHT...A DEEP UPPER TROF SITUATED OVER THE WRN CONUS WILL EJECT SHORTWAVE ENERGY INTO THE CNTRL PLAINS WITH DPVA INDUCING LEESIDE SFC LOW PRESSURE. AS ATTENDANT WARM FRONT LIFTS NWD...EXPECT CONVECTION TO FIRE ALONG THE BNDRY AS IT APPROACHES THE SRN CWA. AGAIN...ENVIRONMENT WILL BE MOISTURE RICH AND WILL LIKELY LEAD TO LOCALLY HEAVY RAINFALL DURING THE OVERNIGHT HOURS. .LONG TERM...(THURSDAY NIGHT THROUGH MONDAY) ISSUED AT 310 AM CDT TUE AUG 19 2014 MAIN FEATURE OF INTEREST IN THE EXTENDED PDS IS DEVELOPMENT OF A BROAD UPPER TROF OVER THE PAC NW IN RESPONSE TO BLOCKING HIGH PRESSURE DOME OVER THE SERN CONUS. MEDIUM RANGE MODELS AT THIS POINT GENERALLY AGREE THAT ANOTHER RELATIVELY COOL CANADIAN AIRMASS WILL SWEEP INTO THE CNTRL PLAINS BY EARLY NEXT WEEK. MATTER OF FACT...MAX TEMPS MON AND TUES MAY WELL END UP BEING JUST A BIT BELOW NORMAL. MEANWHILE...PCPN CHANCES DURING THIS TIME WILL ONCE AGAIN BE CENTERED AROUND A RATHER SLOW MOVING COLD FRONTAL FOLLOWED BY ANOTHER LATE PD LIFTING WARM FRONT. POPS IN GOING FCST LOOK REASONABLE STILL...THUS NO MAJOR CHANGES NEEDED. && .AVIATION...(06Z TAFS FOR KOFK...KLNK AND KOMA.) ISSUED AT 1145 PM CDT MON AUG 18 2014 GENERALLY EXPECT VFR CONDITIONS THROUGH THE PERIOD. PATCHY FOG MAY OCCUR AROUND SUNRISE WITH LIGHT WINDS. THUNDERSTORM CHANCES WILL START TO INCREASE TUESDAY EVENING...BUT LATER TAFS WILL ADDRESS THAT. && .OAX WATCHES/WARNINGS/ADVISORIES... NE...NONE. IA...NONE. && $$ SHORT TERM...DEE LONG TERM...DEE AVIATION...MILLER

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