FXUS64 KOUN 111115
AFDOUN
AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE NORMAN OK
515 AM CST FRI DEC 11 2009
.AVIATION...
12Z TAFS... NAM/GFS AND RELATED GUIDANCE NOT HANDLING THE LOWER
CLOUDS NOW MOVING UP FROM TX. ONLY THE RUC ACKNOWLEDGES THESE
CLOUDS... AND LATEST RUN KEEPS MOVING THEM NE INTO AT LEAST CENTRAL
OK AND HOLDS ON TO THEM THROUGH AT LEAST 21Z. WILL KEEP THE CIGS
IN VFR CATEGORY TODAY AS RUC RH PROGS KEEP THE LAYER OF HIGHEST RH
VERY CLOSE TO 850MB. RETURN FLOW THIS EVENING/TONIGHT SHOULD BRING
CONDITIONS DOWN TO MVFR BUT NAM CIG GUIDANCE LOOKS TOO LOW.
&&
.PREV DISCUSSION... /ISSUED 244 AM CST FRI DEC 11 2009/
DISCUSSION...
WARMING TREND NEXT 3 DAYS AS COLD AIR MASS GRADUALLY MODIFIES.
SHOULD SEE SOME 70S IN THE SW ON SUNDAY UNDER FAVORABLE
SW/DOWNSLOPE FLOW. TEMPERATURE FORECAST SUNDAY NIGHT AND MONDAY IS
APT TO GET TRICKY AS CANADIAN AIR RETURNS. GFS MAY BE
UNDERESTIMATING THE COLD AIR GIVEN HIGHS YESTERDAY OF -15 TO -26F
IN N CANADA AND WIDESPREAD CURRENT READINGS OF -20 TO -43F. 00Z
ECMWF HAS SLOWED THE ARRIVAL OF THE COLD AIR SLIGHTLY FROM ITS 12Z
RUN BUT STILL HAS IT ENTERING N OK BY 12Z MONDAY WITH STRONG COLD
ADVECTION THEREAFTER. IF THIS TIMING IS RIGHT WE WILL SEE EARLY
MORNING HIGHS IN N OK AND STEADY OR FALLING DAYTIME TEMPS. LOWS
SUNDAY NIGHT MAY ALSO BE THE HIGHS MONDAY IN SOME AREAS. WE HAVE
UNDERCUT THE GFS-MOS HIGHS CONSIDERABLY ON MONDAY... RESULTING IN
A SMALL DIURNAL RANGE... AND ADJUSTED THE 3-HR T GRIDS IN AN
ATTEMPT TO DEPICT A NON-DIURNAL TEMPERATURE TREND. TEMPERATURE
GUIDANCE THEREAFTER HAS BEEN MODIFIED IN KEEPING WITH TYPICAL
ARCTIC-AIRMASS TRENDS - SLOWER MODIFICATION AND RELATIVELY LOW
DIURNAL RANGES OF AROUND 15 DEGREES OR LESS.
WILL KEEP SOME LOW POPS GOING IN THE SE TONIGHT INTO SATURDAY FOR
SOME -RA/-DZ WITH WARM ADVECTION BENEATH A WEAK FAST-MOVING
SHORTWAVE TROF THAT IS NOW APPROACHING CA. SLIGHT-CHANCE POPS ARE
IN THE SE AGAIN MONDAY FOR -RA WITH THE CANADIAN FRONTAL PASSAGE.
OTHERWISE THE PATTERN LOOKS DRY WITH HIGH PRESSURE DOMINATING THE
LOW LEVELS. WE MIGHT BE ABLE TO SHAKE OUT A LITTLE -SN OR -FZDZ
BEHIND THE FRONT AROUND MONDAY NIGHT... BUT AT THIS POINT BOTH THE
GFS AND THE ECMWF HAVE ZERO QPF AND SO WILL KEEP POPS BELOW 15.
&&
.PRELIMINARY POINT TEMPS/POPS...
OKLAHOMA CITY OK 44 30 51 37 / 0 10 10 10
HOBART OK 45 30 55 38 / 0 0 10 0
WICHITA FALLS TX 47 36 56 40 / 0 10 10 0
GAGE OK 44 22 54 31 / 0 0 0 0
PONCA CITY OK 46 28 43 33 / 0 0 10 10
DURANT OK 48 36 48 43 / 0 20 30 10
&&
.OUN WATCHES/WARNINGS/ADVISORIES...
OK...NONE.
TX...NONE.
&&
$$
30/24/24
