961
FXUS64 KAMA 271120 AAA
AFDAMA
AREA FORECAST DISCUSSION...UPDATED
NATIONAL WEATHER SERVICE AMARILLO TX
520 AM CST FRI NOV 27 2009
AVIATION
HIGH CLOUDS MOVING INTO THE PANHANDLES FROM THE SOUTH SHOULD CONTINUE
THROUGH THE TAF PERIOD. SO EXPECT VFR CONDITIONS TO PERSIST. WINDS
STAYING UP AROUND 12 TO 14 KNOTS AT KAMA THIS MORNING...WITH VERY
LIGHT WINDS AT KGUY AND DHT. HOWEVER...STRONGER LL WINDS EXIST JUST
ABOVE THE SURFACE AND SHOULD MIX DOWN TO INCREASE WIND SPEEDS AT ALL
TAF SITES BY 16Z OR SO. SURFACE LOW POSITIONED IN NORTHEAST NEW
MEXICO WILL HELP KEEP WINDS DOWN A FEW KNOTS AT KGUY...BUT THINKING
14 TO 18 KNOT WINDS WITH GUSTS IN THE MID 20 KNOT RANGE WILL DEVELOP
AT KAMA AND KDHT. A COLD FRONT WILL MOVE CLOSE TO THE OK PANHANDLE BY
12Z TOMORROW...SO WILL COVER THE FRONTAL PASSAGE IN NEXT TAF ISSUANCE.
JJB
PREV DISCUSSION
/ISSUED 354 AM CST FRI NOV 27 2009/
DISCUSSION...
THE SUBTROPICAL MOISTURE STREAM ASSOCIATED WITH THE WAVE MOVING
ACROSS CHIHUAHUA HAS RESULTED IN INCREASING HIGH LEVEL CLOUDS ACROSS
THE AREA DESPITE THE SUBSIDENCE FROM THE MID LEVEL ANTICYCLONE. AT
THE SURFACE...SOUTHWEST WINDS WILL INCREASE TO 15 TO 25 MPH. THE
RESULTANT DOWNSLOPE CONDITIONS SHOULD SUPPORT TEMPS REACHING THE
LOWER 70S ACROSS MUCH OF THE AREA. THE INCREASING HIGH CLOUDS SHOULD
BE THE ONLY FEATURE THAT PROHIBITS TEMPS FROM WARMING MUCH MORE THAN
THE FORECAST CURRENTLY DEPICTS. ON SATURDAY...THE FIRST COLD FRONT
WILL ARRIVE...DIPPING AS FAR SOUTH AS THE CANADIAN RIVER VALLEY BY
MIDDAY. TEMPS AHEAD OF THE FRONT SHOULD AGAIN WARM INTO THE UPPER
60S AND LOWER 70S...WITH UPPER 50S AND LOWER 60S ACROSS THE NORTH.
SATURDAY NIGHT IS WHEN THE FORECAST BECOMES MORE COMPLICATED. THE
SHORTWAVE CURRENTLY MOVING INTO THE PACNW WILL DIVE TO THE SOUTH
SOUTHEAST...CUTTING OFF OVER SOCAL THROUGH THE WEEKEND. THE NORTHERN
STREAM TROF WILL RAPIDLY MOVE ACROSS THE CENTRAL PLAINS. BETWEEN
THESE FEATURES...MODEST MID LEVEL FRONTOGENESIS...SUPER IMPOSED WITH
NEGATIVE EPV VALUES WILL LIKELY SUPPORT SOME LIGHT TO MODERATE
PRECIP BANDS LATE SATURDAY NIGHT INTO SUNDAY MORNING. ALOFT...AN H25
JET WILL MOVE INTO PLACE TO OUR SOUTHWEST...GIVING THE PANHANDLES A
BRIEF WINDOW OF ENHANCED VERTICAL MOTION. THE PRECIP IS FORECAST TO
CHANGE OVER TO SNOW DURING THE DAY AS THE COLDER AIR DEEPENS.
FORECAST SNOW TOTALS GENERALLY FALL IN THE 1 TO 2 INCH RANGE ACROSS
THE NORTHWEST HALF OF THE CWA...WITH TOTALS UNDER AN INCH IN THE
SOUTHEAST HALF. SNOW SHOULD END QUICKLY SUNDAY EVENING AS MID LEVEL
FRONTOLYSIS DEVELOPS.
MONDAY WILL REMAIN ON THE COOL SIDE. THE LOW CLOUDS ARE EXPECTED TO
BREAK ALLOWING TEMPS TO WARM INTO THE MID/UPPER 40S. WARMER TEMPS
ARE EXPECTED ON TUESDAY AS SOUTHWEST WINDS RETURN...BUT THIS SHOULD
BE SHORT LIVED AS THE NEXT COLD AIRMASS MARCHES SOUTH. THE
OPERATIONAL GFS IS THE OUTLIER OF THE LATEST SUITE OF MEDIUM RANGE
MODELS. IT TAKES THE NEXT WAVE OF COLD AIR AND MOVES IT TO THE EAST
ACROSS THE GREAT LAKES. THE CANADIAN...ECMWF AND UKMET SHOW A
PATTERN RESEMBLES A MCFARLAND SIGNATURE...WHICH WOULD SIGNIFY AN
IMPENDING COLD AIR DUMP. WE HAVE OPTED TO GO MORE ALONG WITH THE
ECMWF FORECAST AND HAVE IGNORED THE 00Z GFS AS IT STILL EXHIBITS
CONSIDERABLE DIFFERENCES AMONG ITS ENSEMBLE MEMBERS. FORECAST TEMPS
FOR THURSDAY AND FRIDAY CURRENTLY HOVER AROUND 40 DEGREES...BUT THIS
MAY BE TOO WARM IF THE PATTERN VERIFIES.
THANKS TO DDC...ABQ...PUB AND LUB FOR THE COORDINATION.
JOHNSON
FIRE WEATHER...
ELEVATED FIRE WEATHER CONDITIONS ARE ANTICIPATED FOR TODAY AS
SOUTHWEST WINDS RESPOND TO LEE CYCLOGENESIS...INCREASING TO 15 TO 20
MPH. MINIMUM RELATIVE HUMIDITIES WILL DROP BELOW 15 PERCENT ACROSS
ALL BUT THE EXTREME EASTERN ZONES THIS AFTERNOON. WE COULD BRIEFLY
SEE CRITICAL THRESHOLDS MET BUT IT APPEARS THAT THIS WILL NOT HAPPEN
FOR THE REQUISITE 3 HOURS TODAY. THEREFORE...NO RED FLAG WARNING
WILL BE ISSUED. HOWEVER...A STRONGLY WORDED FIRE DANGER STATEMENT
WILL BE NEEDED TO HEIGHTEN AWARENESS. RELATIVE HUMIDITIES WILL AGAIN
FALL BELOW 25 PERCENT ACROSS MUCH OF THE AREA ON SATURDAY...BUT IT
APPEARS THAT 20FT WIND SPEEDS WILL GENERALLY REMAIN IN THE 10 TO 15
MPH RANGE. NO FIRE WEATHER CONCERNS ARE ANTICIPATED THROUGHOUT THE
REMAINDER OF THE FORECAST PERIOD.
JOHNSON
AMA WATCHES/WARNINGS/ADVISORIES
TX...NONE.
OK...NONE.
14/24
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