Issued by NWS Omaha/Valley, NE
000 FXUS63 KOAX 090759 AFDOAX AREA FORECAST DISCUSSION NATIONAL WEATHER SERVICE OMAHA/VALLEY NE 259 AM CDT SAT MAY 9 2009 .DISCUSSION... SYNOPSIS...00Z UPPR AIR ANLYS INDCD POTENT UPPR LVL SHRTWV MOVG THRU THE UPPR MS RIVER VALLEY ASSOCIATED WITH A 50 M H5 HEIGHT FALL AT KOAX. SFC LO ASSOCIATED WITH THE SYSTEM WAS NOW OVR SRN WI PER 08Z SFC ANLYS WITH TRAILING CDFNT INTO THE SRN PLAINS. UPSTRM...VERY MINOR SHRTWV TROF WAS NOTED IN NW FLOW OVR WRN MT. FORECAST...SKIES WL BE CLEARING THIS MRNG BEHIND THE DEPARTING UPPR LVL SYSTEM. THIS WL BE SHRT LIVED HOWEVER AS NEXT UPSTREAM WAVE STARTS TO MOV INTO SD THIS AFTN. ALTHOUGH MOISTURE IS VERY LIMITED...MIXING TO NEAR 800 MB AND A H5 TMPS OF -26 /ALNG THE NEB-SD BORDER/ WILL LEAD TO EXPANDING CU DEVELOPMENT THIS AFTN AND MAY AN ISO SHOWER OR TSRA OVER THE FAR NRN CWA. HAVE INSERTED SOME VERY LO POPS AS ANY MEASURABLE ACTIVITY WL BE ISO. OTHERWISE GOOD MIXING AND SOME SUN TODAY WILL ALLOW FOR TMPS TO CLIMB WELL INTO THE 60S. HAVE IN SOME SCHC POPS IN THE NRN CWA THIS EVNG FOR ANY AFTN ACTIVITY THAT LAST PAST 00Z. OTHERWISE WITH CLR SKIES AND LIGHT WINDS...SHLD SEE TMPS DROP PRETTY QUICKLY THIS EVNG AND HAVE LOWERED GOING LOWS A TOUCH IN FAVORED AREAS. THE NEXT UPPR LVL SYSTEM WL QUICKLY BE HEADING AT THE AREA STARTING LATE TONIGHT. DRY AIR IN PLACE AND WEAK ADVECTION WL LEAD TO ONLY A VERY SMALL CHC PRECIP IN THE FAR SW CWA LATE TONIGHT. WK UPPR LVL SHRTWV TROF WL CONT TO SLIDE THRU THE CWA SUN WITH THE GFS STILL STRONGER WITH THE PV ADVECTION ON THE TROF SURFACE. DESPITE WHICH MODEL IS CORRECT...CONTD COLD MID LVL TMPS AND GOOD MIXING IN THE DRY AIR WL LEAD TO SCT SHOWERS AND MAYBE A RUMBLE OF THUNDER. DOES LOOK LIKE THE BEST FORCING WL BE OVR THE CNTRL/SRN CWA AND REMOVED POPS UP NORTH. ALSO REMOVED POPS FOR SUN NIGHT AS SYSTEM APPEARS TO QUICKLY EXIT THE AREA. UPPR LVL PATTERN WILL THEN BRIEFLY UNDERGO A CHANGE AS SHRTWV RIDGE WL START TO BUILD OVERHEAD FOR MON INTO TUES AHEAD OF THE NEXT STRONGER SYSTEM. INCREASED GOING HIGHS A TOUCH ON MON GIVEN THE EXPECTED MIXING AND WARMING TMPS AROUND 800 MB. NEW MODEL SUITE FOR MID WEEK SYSTEM CONTS TO SHOW DISAGREEMENT. EC NOW A LITTLE SLOWER...BUT SIGNIFICANTLY LESS DEEP THAN LAST NIGHT. EITHER WAY SFC FNT DOES NOT REACH THE CWA UNTIL AT LEAST TUES NIGHT INTO WED MRNG. LEFT IN LO CHC POPS FOR SRN CWA ON TUES THOUGH MOISTURE RETURN IS VERY POOR...BUT CLD SEE A SHOWER. OTHERWISE...BEST CHC FOR PRECIP WL COME ON TUES NIGHT INTO WED WITH THE MAIN UPPR LVL SYSTEM. WITH POOR MOISTURE RETURN SVR CHANCES LOOK SMALL ATTM UNLESS BETTER MOISTURE QUALITY CAN MAKE IT UP HERE. BOUSTEAD && .AVIATION... FOR TAF SITES KOFK/KOMA/KLNK FORECAST VALID THROUGH 10/06Z. MVFR STRATUS DECK NOW OVER ALL TAF SITES WILL PUSH EWD THIS MRNG...LEAVING VFR CONDITIONS. MAY SEE AFTN SCT-BKN CU DECK...BUT EXPECT THOSE CIGS TO REMAIN AT OR ABOVE 5KFT. SHOULD SEE BRIEF CLEARING AFTER SUNSET BEFORE MID-LEVEL DECK RETURNS FROM THE S...AFFECTING MAINLY KLNK...BUT ALSO REMAINING AROUND 6KFT OR ABOVE. GUSTY NWLY WINDS WILL DIMINISH THIS MRNG AS HIGH PRESSURE BUILDS INTO THE AREA...BECOMING LT/VAR AFTER SUNSET. MAYES && .OAX WATCHES/WARNINGS/ADVISORIES... NE...NONE. IA...NONE. && $$
