507
FXUS63 KOAX 210243
AFDOAX
AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE OMAHA/VALLEY NE
843 PM CST FRI NOV 20 2009...CORRECTED SHORT TERM
SHORT TERM
TONIGHT THROUGH MONDAY
QUIET WEATHER CONTINUES AS HIGH PRESSURE SLIDES ACROSS THE CNTRL
PLAINS. SUBJECTIVE 12Z UPPER AIR ANALYSIS INDICATES PATTERN CHANGE
IS UNDERWAY...WITH UPPER LOW FINALLY PULLING AWAY TO THE E ACROSS
THE GT LAKES...UPPER TROUGH DIGGING ALONG THE W COAST...AND UPPER
RIDGING EXTENDING FROM THE AZ/CA BORDER THROUGH NRN MT. 1.5PVU
ANALYSIS ALSO INDICATES ELONGATED SHORTWAVE EXTENDING FROM ERN IA
THROUGH KS INTO WRN TX. SOME MOISTURE WAS CREEPING INTO THE CNTRL
PLAINS...WITH 850MB DEWPOINTS OF 2C AT KTOP AND 6C FROM SRN MO INTO
TX. WARMER TEMPS WERE NOTED ACROSS THE ROCKIES BENEATH
UPPER/MID-LEVEL RIDGING.
MAIN FORECAST CONCERN IS POTENTIAL FOR WEATHER IMPACTS AS UPPER
TROUGH DIGS INTO THE W...WITH SHORTWAVES EJECTING AHEAD OF THE MAIN
UPPER LOW. FOR TONIGHT...WX LOOKS QUIET AS UPPER-LEVEL RIDGE MOVES
EWD INTO THE CNTRL PLAINS. CLOUDS WILL BE INCREASING TO THE
S...WHICH COULD START TO SLIDE INTO THE SRN CWA BY MRNG...AND HAVE
HEDGED CLOUDS UP SLIGHTLY STARTING CLOSE TO 12Z AND CONTINUING
THROUGH THE DAY SAT AS MID-LEVEL MOISTURE ADVECTION CONTINUES.
THINK CLOUDS WILL BE ENOUGH TO TEMPER HIGHS...AND HAVE PULLED BACK
TEMPS A BIT IN THE SRN CWA. DID KEEP POPS OUT FOR NOW ON
SAT...LEANING TOWARD DRIER GEM/NAM SOLUTIONS...AS INFLUENCE OF
RIDGING LOOKS LIKELY TO PERSIST. CONTINUED DRIZZLE MENTION ON SAT
NT AS MOISTURE ADVECTION PERSISTS...WITH WEAK SHORTWAVE EVIDENT IN
QG VECTOR CONVERGENCE ADDING JUST ENOUGH LIFT FOR A LITTLE PRECIP.
INCLUDED SCHC TO CHC POPS ON SUN AS COLD FRONT APPROACHES MOIST
PRE-FRONTAL ENVIRONMENT...WITH INCREASING CHCS OF PRECIP AS THE
FRONT MOVES EWD. KEPT MAX TEMPS SOMEWHAT SUPPRESSED ON SUN AS
POTENTIAL FOR CLOUDS/LIGHT PRECIP LINGERS THROUGH A GOOD PART OF THE
DAY. FRONT IS PROGGED TO WASH OUT ON SUN NT/MON AS DEEPER UPPER LOW
DIGS INTO THE PLAINS. SOLUTIONS STILL DIFFER ON TIMING/SPEED/TRACK
OF THAT UPPER LOW...BUT DO EXPECT AT LEAST A SHORT BREAK IN PRECIP
POTENTIAL AND CLOUDS BETWEEN SYSTEMS. HAVE LEANED SLIGHTLY WARMER
ON MON IN THE SRN CWA AS A NOD TOWARD THE SLOWER/FURTHER S ECMWF
SOLUTION...PARTICULARLY IN THE SRN CWA...BUT ALSO KEPT CHC POPS
INTACT.
LONG TERM
MONDAY NIGHT THROUGH FRIDAY
CLOSED LOW WL MOVE INTO THE CNTRL PLAINS LATE MONDAY NIGHT WITH
QUITE A FEW DIFFERENCES REMAINING IN MODEL GUIDANCE. HAVE GONE WITH
THE CONSENSUS AMONG SURROUNDING OFFICES AND HPC TO FOLLOW THE 12Z
ECMWF WHICH DOES SLOW THINGS DOWN FROM THE PREVIOUS RUN. THIS WOULD
PUT THE UPPER LOW CENTERED SOMEWHERE OVER ERN KS BY 12Z WED. IT DOES
NOT LOOK LIKE MUCH COLD AIR WL BE ASSOCIATED WITH THIS SYSTEM BUT
THIS WL CERTAINLY BE MONITORED CLOSELY. CURRENT 12Z ECMWF PLACEMENT
WOULD PUT DEFORMATION ZONE ACROSS MAINLY OUR NORTHERN COUNTIES WHERE
WE HAVE HIGHEST POPS. MANY DETAILS TO BE IRONED OUT IN NEXT SEVERAL
DAYS REGARDING TRACK AND TIMING ON THIS SYSTEM.
AVIATION
TAF SITES KOFK/KOMA/KLNK
18Z TAFS
VFR CONDITIONS UNDER CLEAR SKIES ARE EXPECTED THROUGH SATURDAY
AFTERNOON. PATCHY MVFR FOG MAY DEVELOP NEAR KOMA AND KLNK AROUND 12Z
SATURDAY...AND AN ISOLATED IFR VISIBILITY IS POSSIBLE.
OAX WATCHES/WARNINGS/ADVISORIES
NE...NONE.
IA...NONE.
SHORT TERM...MAYES
LONG TERM...KERN
AVIATION...DERGAN
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