FXUS63 KOAX 072052
AFDOAX
AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE OMAHA/VALLEY NE
252 PM CST SUN NOV 7 2010
.SHORT TERM...TONIGHT THROUGH WEDNESDAY
ANOTHER DRY...FAIR...AND BREEZY DAY IN THE CENTRAL PLAINS.
SUBJECTIVE 12Z UPPER AIR ANALYSIS INDICATES BROAD UPPER RIDGING OVER
MUCH OF THE CENTRAL CONUS...WITH TROUGH DEVELOPING IN WRN US AND
TROUGH EJECTING OUT OF THE ERN US. POTENT EMBEDDED SHORTWAVE WAS
LOCATED NEAR THE 4 CORNERS AT 12Z...WITH WV IMAGERY AND 1.5 PVU
PRESSURE INDICATING IT HAD REACHED CENTRAL CO BY 20Z. WARM AIR DOME
WAS CENTERED ON THE HIGH PLAINS...WITH 850MB TEMP OF 18C AT KOAX
ALLOWING TEMPS TO REACH THE 70S ACROSS THE CWA. MOISTURE REMAINS
SCANT ACROSS THE CONUS...WITH 0-5C DEWPOINTS NUDGING ASHORE IN THE
PAC NW. SFC LOW AT 20Z WAS CENTERED IN NERN CO...WITH DECENT
PRESSURE GRADIENT ACROSS THE CWA ALLOWING WINDS AROUND 15G25KT AGAIN
TODAY.
MAIN FORECAST CONCERNS ARE TIED TO PATTERN CHANGE AS TROUGH DIGS
INTO THE WRN US...WITH SHORTWAVES EJECTING AHEAD OF IT. THROUGH
TUESDAY...BULK FORCING WILL REMAIN WEST OF THE CWA AS WRN TROUGH
NUDGES SLOWLY EASTWARD ACROSS THE ROCKIES...WITH DRY AIRMASS
PRECLUDING ANY PRECIP UNTIL AT LEAST TUESDAY NIGHT. DEEP TROUGH IS
PROGGED TO MOVE ACROSS THE CNTRL PLAINS TUESDAY
NIGHT/WEDNESDAY...DRAGGING A FAIRLY STRONG COLD FRONT THROUGH THE MO
RIVER VALLEY. AFTER A FEW DAYS OF WARM/MOIST AIR ADVECTION UNDER
SRLY FLOW...SHOULD BE ENOUGH LOWER-LEVEL MOISTURE TO SEE MEASURABLE
PRECIP AS THE WAVE/FRONT MOVE THROUGH. HAVE KEPT POPS IN THE FCST
FOR NRN CWA ON WEDNESDAY AS WAVE PASSES THROUGH. MADE FEW CHANGES
TO TEMPS...BUT DID TWEAK UPWARD ON TUESDAY AHEAD OF THE
FRONT...CONTINUING TO FOLLOW THE SLOWER ECMWF/GEM/NAM SOLUTION OVER
THE OUTLIER GFS.
.LONG TERM...WEDNESDAY NIGHT THROUGH SUNDAY
MODELS TODAY ARE IN DECENT AGREEMENT WITH EVOLUTION OF UPPER AIR
PATTERN FROM THE EASTERN PACIFIC ACROSS THE CONUS DURING THE LONG
TERM PERIOD. A BROAD TROUGH WILL BEGIN THE PERIOD WEDNESDAY NIGHT
ACROSS THE WESTERN HALF OF THE COUNTRY...THEN END THE PERIOD
SUNDAY WITH AN EVEN BROADER TROUGH SPRAWLING ACROSS MOST OF THE
COUNTRY AS HIGHLY AMPLIFIED RIDGE BUILDS OFF THE WEST COAST.
HOWEVER MODELS OFFER VARIED SOLUTIONS IN HANDLING MINOR
LOWS/TROUGHS WITHIN THIS LARGER SCALE PATTERN DURING THE
TRANSITION/EVOLUTION THURSDAY THROUGH SATURDAY...THUS TIMING OF
PRECIP CHANCES WILL BE DIFFICULT. AGAIN THIS MORNING...THE 12Z GFS
HAS TRENDED TOWARD SLOWER 00Z ECMWF IN EJECTING LOW/TROUGH THROUGH
THE PLAINS FRIDAY INTO SATURDAY. LATITUDINAL DIFFERENCES PERSIST
WITH GFS FARTHER SOUTH...BUT MEAN TROUGH POSITION IS CONSISTENT.
BOTH GFS AND ECMWF DEVELOP SURFACE LOW IN WESTERN TEXAS THURSDAY
THEN SWING THIS THROUGH MISSOURI SATURDAY. INCREASING BAROCLINICITY
AHEAD OF THE LOW BEGINS THURSDAY FROM WESTERN KANSAS THROUGH
SOUTHEAST NEBRASKA...AND THUS PRECIP CHANCES BEGIN THEN AS WELL.
ISENTROPIC UPGLIDE SHOULD PRODUCE SCATTERED SHOWERS THURSDAY IN
SOUTHEAST NEBRASKA...WITH RAIN CHANCES SPREADING NORTH AND EAST WITH
TIME AS LOW APPROACHES. DAYTIME SOUNDINGS SUGGEST ALL RAIN DURING
THE DAY...BUT LOW LEVEL TEMPERATURE PROFILE THURSDAY NIGHT SIGNALS A
RAIN/SNOW MIX ALONG NORTHERN FRINGE OF PRECIP SHIELD. CURRENT LOW
TRACK WILL BRING AN END TO ANY PRECIP BY FRIDAY NIGHT...LEAVING
SATURDAY AND SUNDAY DRY.
TEMPERATURES THROUGH THE PERIOD WILL TREND DOWNWARD WITH INCREASE IN
CLOUD COVER UNDER COOL AND DEEPENING UPPER TROUGH REGIME. PERSISTENT
NORTHEAST TO NORTH SURFACE FLOW WILL ALSO KEEP TEMPERATURES COOL.
THURSDAY WILL BE THE WARMEST DAY WITH HIGHS IN THE 50S BEFORE
CLOUDS/PRECIP INCREASE LATE IN THE DAY. COOLER 40S ARE FORECAST FOR
FRIDAY THROUGH SUNDAY...WITH LOWS DROPPING INTO THE 20S FOR THE
WEEKEND.
&&
.AVIATION...
TAF SITES KOFK/KOMA/KLNK
18Z TAFS
VFR CONDITIONS WILL CONTINUE THRU TAF PD. WIND SHEAR AROUND 2000
FT LIKELY AGAIN OVERNIGHT AT ALL THREE SITES.
&&
.OAX WATCHES/WARNINGS/ADVISORIES...
NE...NONE.
IA...NONE.
&&
$$
MAYES/DERGAN/FOBERT