FXUS63 KOAX 140811
AFDOAX
AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE OMAHA/VALLEY NE
311 AM CDT SUN AUG 14 2011
.DISCUSSION...
MAIN FORECAST FOCUS DEALS WITH PRECIPITATION CHANCES LATE TONIGHT
THROUGH MONDAY NIGHT AND DIFFERENCES BETWEEN DRIER NAM AND MORE
PRECIP BULLISH GFS/ECMWF.
BEFORE THEN...MORNING SURFACE ANALYSIS/SATELLITE IMAGERY SHOWED
HIGH PRESSURE OVER CENTRAL NEBRASKA WITH CLEAR SKIES MINUS A FEW
CIRRUS STREAMS. ONE MORE PLEASANTLY DRY DAY IN STORE FOR FORECAST
AREA AS SFC WINDS TURN SERLY AS UPPER RIDGE FLATTENS/SHIFTS E
SLIGHTLY. BASED ON H85 TEMPERATURE CHANGE OVER YESTERDAY...MOST
LOCATIONS SHOULD BE A DEG OR TWO WARMER THAN SATURDAY.
STRONG ISENTROPIC UPGLIDE SETS UP TONIGHT...SHOWS UP WELL ON 310
K SURFACE ...ESPECIALLY LATE AND INTO MONDAY MORNING ACCORDING TO
00Z OPERATIONAL RUNS OF GFS/ECMWF. NAM SEEMS TO BE THE ODD MODEL
OUT TO SOME DEGREE AS IT DECREASES THIS LIFT OR FOCUSES MUCH OF IT
SW OF THE AREA BY MONDAY MORNING. WITH SUPPORT OF GFS/ECMWF...POPS
WERE RAISED INTO HIGH CHANCE CATEGORY SPREADING FROM WRN ZONES TO
SRN/ERN ZONES IN 06-12Z AND 12-18Z PERIODS RESPECTIVELY. WITH 15+
C H85 DEWPOINTS NOT TOO FAR AWAY PER 14/00Z UA...FELT THAT EVEN
IF LIFT WAS WEAKER PER NAM...SCATTERED LIGHTER SHOWERS AT LEAST
WOULD MAKE ACROSS MUCH OF THE AREA. RESIDUAL CLOUDS AND PROBABLE
MORNING SHOWERS AT LEAST SHOULD HOLD TEMPERATURES DOWN ON MONDAY.
HOWEVER...RELUCTANT TO DROP THEM TOO MUCH BELOW UPPER 70S IN CASE
ACTIVITY FALLS APART QUICKLY OR SHIFTS SWD PER NAM GIVEN TIME OF
YEAR. FORECAST ISENTROPIC EVEN BY GFS/ECMWF DECREASES OR
REFOCUSES AWAY FROM FORECAST AREA MONDAY AFTERNOON SO WOULD EXPECT
A DECREASE OR ENDING OF THE ACTIVITY BY AFTERNOON AS UPPER RIDGING
BUILDS IN AHEAD OF NEXT TROUGH. STARTED TRIMMING/DROPPING POPS
MON AFTERNOON. DON/T QUITE HAVE A HANDLE ON HOW MONDAY NIGHT WILL
EVOLVE GIVEN SOME POSSIBLE SUBSIDENCE BEHIND CONVECTIVE DEBRIS AND
APPARENT LACK OF UPPER SUPPORT. NONETHELESS...SOME POPS WARRANTED
GIVEN UPGLIDE AGAIN INCREASES AS LOW LEVEL JET FOCUSES ACROSS
FORECAST AREA. THUS A BIT HIGHER POPS WERE CARRIED MON NGT THAN
DURING THE AFTERNOON WITH HIGHEST ACROSS SERN 2/3RD.
TIMING OF NEXT FRONT AND HOW MUCH CONVECTION OCCURS ALONG WILL BE
IN FLUX WITH MODELS ALL A BIT DIFFERENT. AT THIS TIME CARRIED
MODERATELY HIGH CHC POPS WITH A FRONTAL TIMING EXPECTED SOMETIME
TUE NIGHT. DRIER AND A BIT COOLER AIR BEGINS FILTERING IN BEHIND
THIS FRONT ON WED WHICH SHOULD SHUT OFF PCPN CHANCES AT LEAST
ACROSS NRN ZONES IF NOT ENTIRE AREA...ALTHOUGH SOME INDICATIONS
FRONT WILL HANG UP NEAR KS/MO BORDERS. THUS LTL/NO CHANGES MADE IN
CARRYING SMALL POPS S WED NGT. 00Z GFS HAS BACKED OFF A BIT FROM
COOLISH EARLY FALL PATTERN NRN PLAINS FOR NEW DAY 7 AND
BEYOND...AS DID NEW ECMWF...BUT WON/T BE LONG.
&&
.AVIATION...
TAF SITES KOFK/KOMA/KLNK
06Z ISSUANCE.
VFR CONDITIONS WILL CONTINUE AT THE TAF SITES THROUGH THE FORECAST
PERIOD. THERE IS A SLIGHT CHANCE OF SOME PATCHY FOG TOWARDS
DAYBREAK...BUT GIVEN THE LARGER DEW POINT/TEMPERATURE SPREADS AT THE
MOMENT...CONFIDENCE IS NOT HIGH ENOUGH TO INCLUDE IN THE FORECAST.
&&
.OAX WATCHES/WARNINGS/ADVISORIES...
NE...NONE.
IA...NONE.
&&
$$
CHERMOK/DEE