RSS FeedsIssued by NWS Omaha/Valley, NE
000 FXUS63 KOAX 240333 AFDOAX AREA FORECAST DISCUSSION NATIONAL WEATHER SERVICE OMAHA/VALLEY NE 933 PM CST MON NOV 23 2009 .DISCUSSION... UPPR LVL SYSTEM PRETTY MUCH EVOLVING AS FORECAST. 00Z UPPR AIR ANLYS INDCD 90 KT H3 JET MOVG THRU CNTRL KS. UPSTREAM ANOTHER 95 KT H3 JET WAS DIVING THRU WRN CO. INITIAL H5 CLOSED LO WAS LOCATED OVR NW KS...BUT H5 THERMAL TROF WAS LAGGING AND WAS OVR NRN CO AT 00Z. H85 ANLYS INDCD LO NR CNK WITH CDFNT INTO THE SRN PLAINS. INVERTED TROF EXTNDD NWD THRU ERN NEB. H85 0 C ISOTHERM EXTNDD FM ERN SD INTO WRN NEB NR KLBF. AS UPSTREAM 95 KT H3 JET DIVES INTO THE BASE OF TROF...H5 LO IS EXPECTED TO REDEVELOP OVR SRN KS OVERNIGHT AND THEN EJECT NEWD THRU NE KS INTO NRN MO DURING THE DAY ON TUES. INITIAL BAND OF PRECIP /ASSOCIATED WITH H8 THERMAL GRADIENT FM NE NEB INTO NW KS/ IS EXPECTED TO WEAKEN OVERNIGHT AS BETTER FOCUS SHIFTS FARTHER S WITH REDEVELOPING CLOSED LOW OVR SRN KS. THUS HAVE UPDATED TO REMOVE POPS AFTER 09Z OVR THE NW CWA. COMPARISON OF THE NAM/GFS 6 HR FORECAST SOUNDINGS WITH THE 00Z RAOB FM THE AREA INDCS THE NAM HAD A BETTER HANDLE ON THE THERMAL/MOISTURE PROFILE CURRENTLY. THIS SEEMED TO ALSO BE TRUE OF THE 00Z NAM AS WELL. THUS HAVE USED THIS FOR POINT FORECAST SOUNDINGS FOR THE NEXT 24 HOURS. MODIFYING SFC TMPS FOR THE NIGHT AND USING THE NEW POINT SOUNDINGS INDCS LITTLE CHC OF PRECIP ACTUALLY SWITCHING OVR TO SNOW DESPITE SUCH A STG SYSTEM. THUS HAVE REMOVED SN MENTION FM THE GRIDS AND ANY ACCUM WE HAD GOING. HAVE DONE THE SAME FOR TUES AS WELL OVR THE CWA. DID INCREASE GOING POPS ALNG THE MO RIVER AND POINTS E ON TUES AS THIS AREA SHLD BE WITHIN THE E-W DEFORMATION ZONE /TROWAL/ AREA AS THE SYSTEM MOVES INTO IA. NEW GRIDS/ZFP WL BE OUT BY 10 PM. BOUSTEAD && .PREV DISCUSSION... /ISSUED 311 PM CST MON NOV 23 2009/ SHORT TERM...TONIGHT THROUGH THURSDAY. WV IMAGERY SHOWING INITIAL SHORTWAVE TROF OF INTEREST WAS SITUATED OVER THE CNTRL CONUS WITH ANOTHER WAVE UPSTREAM COMING ASHORE OVER WRN CANADA. GOOD AGREEMENT THAT MAX OMEGA PHASES WELL WITH MID/UPR QVECT CONVERGENCE AND DEEP LYR MOISTURE OVER THE CWA TONIGHT AS INITIAL UPPER LEVEL TROF GRADUALLY TRACKS EAST OVER THE REGION. SFC REFLECTION WILL STRENGTHEN DURING THIS TIME OVER KANSAS AND DRAG A COLD FRONT DEEP INTO THE CNTRL/SRN PLAINS. THE QUICK MOVING BOUNDARY IS PROGGED TO BE PUSHING ACROSS WRN MO/WRN AR/ERN TX BY 12Z TUES. AT THAT TIME MODELS TAKE THE BRUNT OF DYNAMIC FORCING INTO THE MID MS VLY...HOWEVER CANNOT RULE OUT LINGERING ACTIVITY THRU TUESDAY AFTN ON THE BACKSIDE OF THE EXITING SYSTEM. AS FOR PCPN TYPE...AM SEEING LITTLE PER COBB BUFKIT DATA/CRITICAL THKNS TO SUGGEST ANYTHING MORE THAN A POTENTIAL FOR RA/SN MIX LATE TONIGHT OVER NORTHEAST NEB. COME TUESDAY NIGHT...THE NEXT SHORTWAVE TROF OF CONCERN DROPS DOWN THRU THE DAKOTAS/MN WITH ACCOMPANYING SECONDARY SHOT OF COLD AIR FUNNELING SWD. AGAIN...VERY STRONG LIFT WITH THIS SECOND WAVE AND RE-ENFORCING COLD AIRMASS BUT WITH LITTLE MOISTURE TO TAP INTO EXPECT DRY FROPA. OTHERWISE...THE SERIES SFC COLD FRONT MOVING THRU ARE RELATIVELY WEAK AND ANTICIPATE RESULT WILL BE ONLY SLIGHTLY BELOW NORMAL AFTN HIGHS TUES-THURS. LONG TERM...THURSDAY NIGHT THROUGH MONDAY. MODELS ARE IN VERY GOOD AGREEMENT WITH THE LARGE SCALE PATTERN AT THE START OF THIS PERIOD. THEY SHOW ONE TROUGH ENTERING THE WEST COAST FROM CNTRL CA NORTHWARD AND ANOTHER OVER THE ERN U.S. AT 00Z FRIDAY. OUR AREA IS IN NORTHWEST FLOW...WITH A RIDGE OVER THE ROCKIES AND HIGH PLAINS. THE PATTERN WILL BE PROGRESSIVE...WITH A BROAD TROUGH OVER THE ROCKIES AND MUCH OF THE PLAINS BY LATE SATURDAY. TWO DIFFERENT UPPER LEVEL LOWS DEVELOP OVER THE WEEKEND. ONE WILL DIG OVER THE FOUR CORNERS REGION...WHILE ANOTHER DEVELOPS OVER THE NORTHERN PLAINS. IN REGARDS TO THE NORTHERN PLAINS SYSTEM...THE 12Z GFS APPEARS TO BE A COMPROMISE OF THE 12Z CANADIAN GEM AND THE 12Z ECMWF. THE GEM DEVELOPS PCPN FROM THE EASTERN DAKOTA AND MINNESOTA SOUTHWARD INTO EASTERN NEBRASKA SATURDAY. THE 12Z GFS IS MAINLY DRY FOR OUR AREA UNTIL SUNDAY NIGHT OR MONDAY...WHEN IT SUGGESTS SOME LIGHT SNOW. THE 00Z AND 12Z ECWWF WERE MAINLY DRY. EXPECT LOWS DURING THIS PERIOD IN THE 20S TO LOWER 30S AND HIGHS IN THE 40S TO LOWER 50S. AVIATION... TAF SITES KOFK/KOMA/KLNK 18Z TAFS SFC LOW PRESSURE OVER WESTERN OKLAHOMA WL CONTINUE TO MOVE NEWD OVERNIGHT AND TOWARD SERN NEB BY 06Z TONIGHT. PCPN IS EXPECTED TO MOVE TOWARD TAF SITES LATER THIS EVENING AND MAINLY IN THE FORM OF RAIN. SOME SNOW COULD MIX IN OVERNIGHT AROUND KOFK...BUT CHANCES ARE SO SLIM THAT WL NOT MENTION AT THIS POINT. PCPN IS EXPECTED TO CONTINUE OVERNIGHT AND BEGIN TO TAPER OFF BY MORNING. GUSTY NW WINDS ARE EXPECTED AS WELL. CIGS SHOULD VARY BETWEEN MVFR AND IFR THRU MUCH OF THE PD. && .OAX WATCHES/WARNINGS/ADVISORIES... NE...NONE. IA...NONE. && $$
