FXUS64 KAMA 290546 AAB
AFDAMA
AREA FORECAST DISCUSSION...UPDATED
NATIONAL WEATHER SERVICE AMARILLO TX
1146 PM CST SAT NOV 28 2009
.AVIATION...
NORTHERLY WINDS BEGINNING TO PICK UP IN WAKE OF COLD FRONT...WITH
SPEEDS INCREASING INTO THE 15 TO 20 KNOT RANGE. CLOUDS WILL CONTINUE
TO INCREASE THROUGHOUT THE OVERNIGHT HOURS...WITH HEIGHTS LOWERING AS
COLUMN SATURATES FROM THE TOP DOWN. MVFR CIGS WILL BE POSSIBLE BY
13Z/14Z...WITH LIGHT RAIN POSSIBLE AT AMA AND DHT. IMPROVING
CONDITIONS CAN BE EXPECTED AT GUY BY 20Z...BUT HELD ON TO MVFR CIGS
THROUGH THE REMAINDER OF THE PERIOD AT DHT/AMA.
TAB
&&
.PREV DISCUSSION... /ISSUED 612 PM CST SAT NOV 28 2009/
AVIATION...
COLD FRONT HAS PUSHED THROUGH THE DHT AND GUY TAF SITES...AND SHOULD
PUSH THROUGH AMA BY 02Z. MID AND HIGH LEVEL CLOUDS WILL BE ON THE
INCREASE THROUGH THE EVENING HOURS...WITH VFR CONDITIONS EXPECTED
THROUGH TONIGHT. BROUGHT MVFR CIGS TO ALL TAF SITES AROUND 13Z/14Z AS
LOWER LEVELS WILL BEGIN TO SATURATE. RETAINED -RA REMARKS AT DHT/AMA
IN THE 13Z TO 20Z TIME FRAME...LOWER CONFIDENCE OF PRECIP OCCURRING
AT GUY PRECLUDE MENTIONING IN THE TAFS ATTM. KEPT PRECIP TYPE AS ALL
RAIN FOR NOW BUT MAY NEED TO CONSIDER A RAIN/SNOW AT LEAST FOR DHT.
TAB
PREV DISCUSSION... /ISSUED 340 PM CST SAT NOV 28 2009/
DISCUSSION...
FORECAST ISSUES CONTINUE TO REVOLVE AROUND EXPECTED PRECIP SUNDAY
FOLLOWED BY THE NEXT CHANCE OF PRECIP TUESDAY.
WATER VAPOR IMAGERY THIS AFTERNOON INDICATES DEEP UPPER LOW OVER
SOUTHERN CA WITH A BROAD NORTHERN STREAM UPPER TROUGH ACROSS THE
NORTHERN PLAINS. CONTINUE TO SEE MID/HIGH LEVEL CLOUDS
INCREASE ACROSS THE AREA AS SUBTROPICAL MOISTURE AHEAD OF THE UPPER
LOW LIFTS ACROSS CO/NM. MODEL GUIDANCE IS IN GOOD AGREEMENT IN
DIGGING THE LOW INTO OLD MEXICO SUNDAY. CURRENT SFC OBS INDICATE
FAIRLY LARGE TEMP/DEW POINT SPREADS AHEAD OF A STRONG COLD FRONT
SO EXPECT THAT IT WILL TAKE SOME TIME FOR THE COLUMN TO SATURATE
TONIGHT. WITH THIS IN MIND HAVE TRIMMED BACK POPS THIS EVENING AND
MAINTAINED CHANCE TO SLIGHT CHANCE POPS ACROSS ALL BUT THE NORTHEAST
ZONES OVERNIGHT TONIGHT. WITH THE UPPER LOW WELL WEST OF THE AREA...
MOST OF THE FORCING WILL BE TIED TO A 130KT JET STREAK AS IT LIFTS
ACROSS THE SOUTHERN PLAINS SUNDAY. FAVORABLE LEFT EXIT REGION OF THE
JET STREAK COMBINED WITH MID LEVEL FRONTOGENETICAL FORCING WILL
SUPPORT PRECIP CHANCES. NAM CONTINUES TO HAVE A DRY BIAS AND ONLY
GIVES SOME SPOTTY QPF DURING THE DAY WHILE THE ECMWF/GFS/GEM/UKMET
ARE ALL A BIT MORE GENEROUS WITH PRECIP. GIVEN THE INCREASING
VERTICAL MOTION...THE WETTER GFS MIGHT HAVE A BETTER HANDLE ON
THINGS. PRECIP TYPE THOUGH CAN BE TRICKY. NAM/GFS FORECAST SOUNDINGS
INDICATE TEMPS REMAINING ABOVE FREEZING IN THE LOWEST 50 HPA LAYER
WHICH WOULD SUPPORT RAIN RATHER THAN SNOW. THIS OF COURSE WOULD END
UP CUTTING BACK EVEN FURTHER ON SNOW AMOUNTS. WITH THIS IN MIND...
INSERTED MENTION OF RAIN MOST AREAS ALTHOUGH WITH TEMPS FALLING TO
NEAR OR BELOW FREEZING IN THE NORTHWEST...A RAIN SNOW MIX IS POSSIBLE
OVERNIGHT. MAIN PUSH OF COLDER AIR LOOKS TO ARRIVE SUNDAY. MODELS
HAVE BACKED OFF A LITTLE ON THE AMOUNT OF COLD AIR WRAPPING IN
BEHIND THE FRONT ALTHOUGH WITH THICK CLOUD COVER AND COLD ADVECTION
ON NORTHERLY WINDS...HIGHS IN THE LOWER 40S TO NEAR 50 LOOK
REASONABLE.
PRECIP WILL END QUICKLY BY SUNDAY EVENING AS THE UPPER JET LIFTS
INTO THE LOWER MS VALLEY. SFC HIGH PRESSURE BUILDS INTO THE ROCKIES
SUNDAY EVENING. EXPECT CLOUDS TO THIN OVERNIGHT AS SUBSIDENCE FROM
THIS HIGH INFLUENCES THE AREA. LIGHT NORTH WINDS SHOULD REINFORCE
THE COOL AIR MASS ACROSS THE AREA SO EXPECT HIGHS IN THE MID 40S TO
MID 50S. ATTENTION THEN TURNS TO THE TRACK OF THE UPPER LOW.
GFS/ECMWF ARE TRACKING THE LOW FURTHER TO THE NORTH WITH DEFORMATION
TYPE PRECIP AFFECTING THE SOUTHERN TX PANHANDLE. AN ADDITIONAL PUSH
OF COLDER AIR LOOKS POSSIBLE WHICH WOULD SUPPORT A RAIN SNOW MIX. HAVE
INSERTED SLIGHT CHANCE POPS ACROSS THE SOUTHERN TX PANHANDLE WITH A
RAIN SNOW MENTION. MADE LITTLE CHANGES TO THE FORECAST BEYOND TUESDAY
WITH RIDGING TAKING PLACE ALONG THE WEST COAST. THIS PATTERN SUGGEST
THE MORE WINTRY AIR MASS TO REMAIN ACROSS THE AREA.
CLK
FIRE WEATHER...
A STRONG COLD FRONT WILL PUSH ACROSS THE PANHANDLES TONIGHT. MUCH
COLDER AIR WILL ACCOMPANY THIS FRONT...WHICH WILL CAUSE TEMPS TO
FALL TO BELOW SEASONABLE NORMALS SUNDAY. IN ADDITION...THE
REGION WILL SEE A CHANCE OF LIGHT RAIN WITH A LIGHT RAIN SNOW
MIX IN THE NORTHWEST PORTIONS OF THE PANHANDLE. THIS WILL PRECLUDE
FIRE WEATHER CONDITIONS SUNDAY. ANOTHER CHANCE OF PRECIPITATION IS
EXPECTED TUESDAY AND WITH RELATIVE HUMIDITIES EXPECTED TO REMAIN
ABOVE CRITICAL THRESHOLDS...NO FIRE WEATHER CONCERNS ARE
ANTICIPATED THROUGH THE FORECAST PERIOD.
CLK
&&
.AMA WATCHES/WARNINGS/ADVISORIES...
TX...NONE.
OK...NONE.
&&
$$
10/02
