FXUS63 KOAX 181942
AFDOAX
AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE OMAHA/VALLEY NE
242 PM CDT FRI MAR 18 2011
.SHORT TERM...TONIGHT THROUGH MONDAY.
CONVECTION CHANCES...ESPECIALLY LATE SATURDAY NIGHT AND THEN AGAIN
SUNDAY/MONDAY AFTERNOON MAIN PRECIPITATION CHALLENGE IN SHORTER
TERM. REGARDING TEMPERATURES...HOW QUICKLY WARM ADVECTION
CLOUDINESS ARRIVES ON SATURDAY...HOW QUICKLY IT CLEARS OUT SUNDAY
AND THEN POTENTIALLY LINGERING MOISTURE ON MONDAY CREATES A BIT OF
POTENTIAL TEMPERATURE BUST EACH DAY.
FOR TONIGHT...WITH SURFACE RIDGE AXIS WORKING DOWN MO RIVER VALLEY
AT LEAST EARLY TONIGHT...FELT ENOUGH OF A FALL-OFF IN DEW POINTS
THAT WITH CLEAR/CLEARING SKIES AND LIGHT WINDS MANY LOWS NEEDED
LOWERING A BIT...ESPECIALLY WESTERN IA. ON SATURDAY PUSHED BACK
INCREASE IN CLOUDS A TOUCH AND SINCE FORCING WAS FAIRLY WEAK YET
AND MOSTLY WARM ADVECTION DRIVEN NOT TOO IMPRESSED WITH PRECIP
CHANCES. SREF...09Z RUN...WAS ALSO NOT TO SUPPORTIVE WITH
QPF...MAINLY WEST OR SOUTH OF THE FORECAST AREA. THUS REDUCED POPS
OR DELAYED THEM JUST A BIT. HOWEVER...WAS NOT QUITE CONFIDENT ENOUGH
REGARDING CLOUD FORECAST...OR LACK OF THEM...WITH THIS FORECAST TO
APPRECIABLY RAISE TEMPERATURES FOR SATURDAY.
BEST CONVECTION CHANCES STILL APPEAR TO BE SATURDAY NIGHT...
ESPECIALLY LATE...AS NEGATIVE H85 LIFTED INDICES ADVECT ACROSS
THE ENTIRE FORECAST AREA AS LOW LEVEL JET INCREASES. COULD BE TWO
AREAS OF FOCUS...ONE ACROSS NERN ZONES ON NOSE OF THIS INSTABILITY
INCREASE...WHICH WAS BACKED BY QPF FROM 09Z SREF. THE SECOND WOULD
BE ACROSS OR JUST SE OF FAR SERN ZONES WHICH 12Z OPERATIONAL
GFS/NAM AND 00Z ECMWF SUGGESTED AND HIGHEST POPS WERE PREVIOUSLY
FORECAST. LEFT LIKELY POPS GOING FAR SE WHERE CAP WAS FORECAST TO
BE A BIT WEAKER...BUT INCREASED THEM A BIT FROM AROUND OLU NEWD
INTO FAR NERN ZONES. APPEARS A BIT STRONGER SHORTWAVE TROUGH
LIFTING NNW OF NEBRASKA ON SUNDAY WILL LIFT WARM FRONT NORTHEAST
AT LEAST NORTH OF OUR SOUTHERN ZONES IF NOT FARTHER NORTH. THUS
INTRODUCED SOME LOW/MID 70S FOR HIGHS FM LNK TO JUST S/SE OF OMAHA AND
RAISED HIGHS NW OF THERE AS WELL. LEFT IN SMALL THUNDERSTORM
CHANCES ALONG FRONT SUNDAY AFTN/NIGHT BUT REMOVED ELSEWHERE WHERE
FORCING WAS MARGINAL AND CAP STRENGTHENING. MID LEVEL/HIGHER BASED
CUMULUS/STRATOCU COULD THICKEN/INCREASE NORTH OF THE FRONT ON
MONDAY...BUT 12Z NAN/GFS SUGGESTED AT LEAST SOME SUNSHINE TO HELP
BOOST MANY TEMPERATURES BACK INTO AT LEAST THE 60S...OVER
SOUTHERN HALF AT LEAST. AT THIS TIME PRECIP CHANCES ARE SOMEWHAT
QUESTIONABLE AS FORECAST SOUNDINGS LEAVE IN SOME SORT OF
CAP...ALTHOUGH IT WAS NOT QUITE AS STRONG NORTH OF BOUNDARY.
HOWEVER...09Z SREF WAS MORE AGGRESSIVE IN SPREADING PRECIP OVER
THE FORECAST AREA SO NOT ONLY LEFT SOME MENTION IN...PULLED THE
SLIGHT CHANCE NWD UP TO OMAHA VICINITY.
.LONG TERM...MONDAY NIGHT THROUGH FRIDAY.
PERIOD BEGINS WITH GOOD MODEL AGREEMENT REGARDING STRONG WEST COAST
TROF MOVING INLAND AND EVENTUALLY TOWARD THE NORTHERN CENTRAL PLAINS
AREA. AHEAD OF THIS...SFC CYCLOGENESIS WL BE UNDERWAY OVER THE HIGH
PLAINS REGION. MODEL CONSENSUS CONTINUES TO PLACE A SFC WRMFNT
ACROSS THE FORECAST AREA OVERNIGHT MONDAY INTO TUESDAY MORNING WITH
A STRONG SOUTHWEST LOW LEVEL JET. HAVE WARMED UP TEMPS TUESDAY
MORNING AS WELL AS HIGHS ON TUESDAY ALONG WITH SFC
DEWPOINTS...ESPECIALLY IN OUR SOUTH. WL CONTINUE WITH CHANCE POPS
FOR THUNDERSTORMS AS INSTABILITY INCREASES ALONG THE BOUNDARY. THE
MAIN UPPER LOW IS FORECAST TO MOVE EAST ACROSS THE DAKOTAS AND
EVENTUALLY MOVE MORE SOUTHEAST BY WED NIGHT. THIS WILL ALLOW A SLUG
OF COLDER AIR TO POSSIBLY SLIDE SOUTH INTO THE REGION. COOLER AND
DRY CONDITIONS ARE EXPECTED BY LATE IN THE PERIOD.
&&
.AVIATION...
TAF SITES KOFK/KOMA/KLNK
18Z TAFS
VFR CONDITIONS ARE EXPECTED AT ALL THREE TAF SITES THROUGH THIS
FORECAST PERIOD WITH THINNING HIGH CLOUDS ACROSS THE REGION THROUGH
00Z. MID CLOUDS EXPECTED TO INCREASE AFTER 09Z AS WARM ADVECTION
INTENSIFIES IN ADVANCE OF INITIAL WAVE COMING OUT OF THE SW CONUS.
&&
.OAX WATCHES/WARNINGS/ADVISORIES...
NE...NONE.
IA...NONE.
&&
$$
CHERMOK/KERN/FOBERT