052 
FXUS63 KOAX 180450
AFDOAX

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE OMAHA/VALLEY NE
1150 PM CDT WED JUL 17 2013


.AVIATION...06Z TAFS FOR KOFK...KLNK AND KOMA.

VFR CONDITIONS EXPECTED THRU THE FCST PD. 

DEE

&&

PREV DISCUSSION... /ISSUED 312 PM CDT WED JUL 17 2013/ 

DISCUSSION...

ALTHOUGH OVERALL FORECAST CHALLENGE IS WHEN TO INCLUDE
PRECIPITATION CHANCES...TEMPERATURES WERE THE PRIMARY FOCUS IN
THE SHORTER TERM.

TONIGHT/THURSDAY...WILL COUNT ON ANY ACTIVITY THAT MANAGES TO
DEVELOP YET THIS AFTN IN WEAK DISTURBANCE LIFTING SLOWLY N TOWARD
SRN IA TO HAVE MOSTLY DISSIPATED BY 00Z AND WILL MAINTAIN A DRY
FORECAST TONIGHT. OTHERWISE LOW PRESSURE FORECAST TO DEEPEN SOME
OVER THE NRN PLAINS TONIGHT/THURSDAY AHEAD OF AN UPPER TROUGH
DROPPING ACROSS SRN CANADA SHOULD KEEP WINDS UP A BIT MORE TONIGHT
AND PROVIDE A LITTLE STRONGER SSW WINDS ON THURSDAY. THIS SHOULD
IN TURN KEEP MIN TEMPS UP A BIT TONIGHT COMPARED TO THIS MORNING
WITH HIGHS THURSDAY GENERALLY A LITTLE WARMER THAN TODAY. FORECAST
DWPTS AND HIGHS KEPT HEAT INDEX VALUES GENERALLY UNDER 100 SO NO
HEADLINES FOR HEAT YET.

AFOREMENTIONED UPPER TROUGH/SFC LOW WILL BE PUSHING A COLD FRONT
ACROSS THE AREA THURSDAY NIGHT/FRIDAY. SMALL POPS...GENERALLY IN
SLIGHT CHC RANGE...WERE MAINTAINED ALONG/JUST BEHIND FRONT. LOW
LEVEL CONVERGENCE NOT THE BEST AND UPPER HEIGHTS OVER THE FORECAST
AREA AND MID LEVEL TEMPS FORECAST BEHIND FRONT REMAINED
UNFAVORABLE...RE...HIGH. WINDS COULD DECREASE JUST ENOUGH NEAR
FRONT TO ALLOW LOWS PARTS OF NERN NEBR FRIDAY MORNING TO BE A
LITTLE COOLER THAN TOMORROW MORNING...OTHERWISE LOWS SHOULD BE A
DEG OR TWO MILDER WITH MODEST WINDS. INITIAL COOLING APPEARS
MINIMAL BEHIND FRONT ON FRIDAY...BUT READINGS SHOULD BE A FEW
DEGREES COOLER ALL BUT FAR SOUTH.

SOME DISAGREEMENT AMONGST MODELS IN FRIDAY NIGHT-SATURDAY PERIOD
WITH NAM VERY AGGRESSIVELY GENERATING AN MCS LATE FRIDAY NIGHT NW
OF FORECAST AREA AND DROPPING IT INTO THE AREA SATURDAY.
GFS/ECMWF WERE GENERALLY SLOWER AND FARTHER NW WITH ANYTHING AS
BETTER LOW LEVEL THETAE ADVECTION WAS MORE FOCUSED TO OUR WEST.
THUS FOR NOW DISCOUNTED NAM AND KEPT FRIDAY NIGHT DRY OVER THE FA
WITH ONLY SLIGHT CHC POPS NWRN ZONES ON SATURDAY AS THE WARM/MORE
MOIST AIR ATTEMPTS LIFTING NE. EVEN IF NO PRECIP OVER THE AREA ON
SATURDAY...THERE COULD BE ENOUGH WARM ADVCTN CLOUDS TO GO ALONG
WITH SLIGHTLY COOLER H85 TEMPS TO KEEP HIGHS A LITTLE COOLER THAN
FRIDAY.

MODEST CHC POPS WERE MAINTAINED IN SAT NIGHT/SUNDAY PERIOD AS
THIS THETAE ADVECTION SHIFTS OVER THE FORECAST AREA. LITTLE
CHANGES WERE MADE TO TEMPS. AT THIS TIME...THIS PERIOD APPEARS 
TO CONTAIN THE BEST CHANCES FOR PRECIP OVER THE WIDEST PART OF THE
FA FOR THIS 7 DAY FORECAST.

NORTHWESTERLY UPPER FLOW WITH A SERIES OF PSBLE EMBEDDED WAVES
THEN EXPECTED IN SUNDAY THROUGH WEDNESDAY PERIOD WITH UPPER RIDGE
GENERALLY PUSHED TO THE WRN U.S. OR SQUISHED S OVER SERN U.S. SOME
DIFFERENCES IN TIMING OF APPARENT BETTER CHCS OF PRECIP BETWEEN
GFS/ECMWF WITH GFS KEYING ON MON NIGHT/EARLY TUE AND ECMWF
GENERALLY THE NEXT NIGHT. FOR NOW FORECAST CONSISTED OF A ENSEMBLE
OF MODELS...PREVIOUS FORECAST AND SURROUNDING SITES NUMBERS AS
CONFIDENCE WAS LOW.

CHERMOK

&&

.OAX WATCHES/WARNINGS/ADVISORIES...
NE...NONE.
IA...NONE.
&&

$$

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