000
FXUS64 KAMA 181716 AAA
AFDAMA

AREA FORECAST DISCUSSION...UPDATED
NATIONAL WEATHER SERVICE AMARILLO TX
1216 PM CDT SAT MAY 18 2013

.UPDATE...
QUICK UPDATE ISSUED TO REMOVE MENTION OF MORNING FOG AND TWEAK
TEMPERATURES UPWARD IN SOME LOCATIONS. HEAT BURST ACTIVITY OVERNIGHT
RESULTED IN A VERY WARM START TO THE DAY IN SOME LOCATIONS...AND
TEMPS CONTINUE TO WARM AIDED BY SOUTH TO SOUTHWEST WINDS AND
INCREASINGLY DRY AIR BEHIND THE EASTWARD MIXING DRYLINE. THE RECORD
HIGH OF 102F AT AMARILLO AND 100F AT BORGER WILL BOTH BE IN JEOPARDY
TODAY...ALTHOUGH IT CURRENTLY LOOKS LIKE BORGER WILL HAVE THE BETTER
CHANCE OF BREAKING THE RECORD.

FOR THIS AFTERNOON AND EVENING...THINGS STILL GENERALLY LOOK ON TRACK
WITH EARLIER THINKING REGARDING CRITICAL FIRE WEATHER CONDITIONS
BEHIND THE DRYLINE AND THE POSSIBILITY FOR SEVERE CONVECTION ALONG
AND AHEAD OF IT. WILL LEAVE THE RED FLAG WARNING AS IS...WITH NO
CHANGES PLANNED TO IT ATTM ALTHOUGH WINDS ARE LOOKING A LITTLE MORE
MARGINAL NOW IN SOME LOCATIONS.

AS FAR AS SEVERE WEATHER POTENTIAL GOES...IT CONTINUES TO LOOK LIKE
THE EASTERN PANHANDLES WILL BE ON THE WESTERN FRINGE OF THE SEVERE
WEATHER THREAT LATER THIS AFTERNOON AND EVENING. THE DRYLINE IS
EXPECTED TO MIX TO NEAR THE OK STATE LINE BY THE TIME CONVECTION
INITIATES AFTER 3 PM. STILL TOUGH TO SAY WHETHER IT WILL HANG UP IN
OUR FAR EAST OR MIX INTO FAR WESTERN OK. IF IT DOES HANG UP IN OUR
FAR EAST...INSTABILITY AND DEEP LAYER SHEAR WILL BE MORE THAN
ADEQUATE TO SUPPORT SEVERE STORMS. CONVECTION IS EXPECTED TO REMAIN
ISOLATED IN OUR AREA AS IT BATTLES A FAIRLY STRONG CAP AND ALSO
PERHAPS SOME SUBSIDENCE BEHIND A DEPARTING SHORTWAVE. LARGE HAIL AND
DAMAGING WINDS ARE EXPECTED TO BE THE PRIMARY HAZARDS WITH ANY
CONVECTION THAT DOES DEVELOP IN THE EASTERN PANHANDLES. HIGHER LCL
HEIGHTS WILL KEEP THE TORNADO THREAT MUCH LOWER...AND EXPECT THE MAIN
TORNADO THREAT TO REMAIN EAST/NORTHEAST OF THE PANHANDLES WHERE LOW-
LEVEL SHEAR/SRH WILL INCREASE MARKEDLY THIS EVENING WITH ONSET OF THE
NOCTURNAL LLJ.

KB

&&

.PREV DISCUSSION... /ISSUED 639 AM CDT SAT MAY 18 2013/

AVIATION...
12Z TAF CYCLE
AN UPPER TROUGH WILL MOVE FROM THE FOUR CORNERS REGION AND ACROSS THE
CENTRAL AND SOUTHERN ROCKIES BY TONIGHT. A DRYLINE WILL MOVE TO THE
CAPROCK OR OFF THE CAPROCK BY THIS AFTERNOON. VFR CONDITIONS WILL
PREVAIL THROUGH 12Z SUNDAY AS LIGHT WINDS 5 TO 15 KNOTS OR LESS BECOME
SOUTHWESTERLY TO WESTERLY 15 TO 25 KNOTS WITH HIGHER GUSTS AFTER 15Z
TODAY AT ALL THREE TAF SITES....THEN DIMINISH TO AROUND 5 TO 15 KNOTS
AFTER 01Z SUNDAY.

SCHNEIDER

PREV DISCUSSION... /ISSUED 446 AM CDT SAT MAY 18 2013/

DISCUSSION...
AS ADVERTISED TODAY WILL SEE FIRE WEATHER CONCERNS FOR THE MAJORITY
OF THE TEXAS AND OKLAHOMA PANHANDLE WITH ISOLATED SEVERE STORMS
POSSIBLE ACROSS THE FAR EASTERN TEXAS AND OKLAHOMA PANHANDLE.

THE RETREATED DRYLINE HAS PROVIDED THE OPPORTUNITY FOR FOG...LOW
CLOUDS...AND SOME VIRGA SHOWERS TO DEVELOP THIS MORNING. HOWEVER...THE
DRYLINE WILL ONCE AGAIN SURGE TO THE EAST DURING THE LATE MORNING.
MODELS STILL HAVE A LITTLE VARIATION ON JUST HOW FAR THE DRYLINE WILL
PROGRESS TODAY BEFORE BECOMING STATIONARY. HAVE GONE ROUGHLY WITH A
BEAVER TO CLARENDON LINE FOR THE DRYLINE POSITION BY THE AFTERNOON.
BEHIND THE DRYLINE RELATIVE HUMIDITIES WILL PLUMMET INTO THE TEENS
AND SINGLE DIGITS FROM EAST TO WEST. COUPLING THESE LOW RELATIVE
HUMIDITIES WITH BREEZY CONDITIONS YOU END UP WITH PRIME CONDITIONS
FOR THE SPREAD OF FIRES. AS SUCH HAVE GONE AHEAD AND UPGRADED THE FIRE
WEATHER WATCH TO A RED FLAG WARNING FOR THIS AFTERNOON AND EVENING
HOURS. OVERNIGHT WINDS ARE EXPECTED TO DECREASE AS RELATIVE
HUMIDITIES REBOUND BRINGING AN END TO THESE CRITICAL FIRE WEATHER
CONDITIONS.

NOW THAT WE HAVE TALKED ABOUT THE FIRE WEATHER POTENTIAL LETS DIVE
INTO THE SEVERE POTENTIAL. DURING THE SAME TIME THAT THE DRYLINE
WILL BE SURGING EASTWARD AN UPPER TROUGH WILL BE APPROACHING THE
PANHANDLES FROM THE WEST. OUR SEVERE POTENTIAL WILL BE DEPENDENT ON
TWO MAIN FACTORS: THE LOCATION OF THE DRYLINE AND THE ABILITY TO
BREAK THE CAP.

AS MENTIONED ABOVE THERE STILL REMAINS SLIGHT VARIATIONS ON THE
LOCATION OF THE DRYLINE THIS AFTERNOON. THE GFS AND NAM ARE THE MOST
PROGRESSIVE IN SENDING THE DRYLINE INTO WESTERN OKLAHOMA WHILE THE
ECMWF AND CMC HAVE COME INTO MODEST AGREEMENT...IF YOU
SQUINT...KEEPING THE DRYLINE IN THE FAR EASTERN TEXAS/OKLAHOMA
PANHANDLE. HAVE GONE WITH THE FURTHER WESTERN POSITIONING OF THE
DRYLINE WHICH LEAVES LOCATIONS EAST OF A BEAVER TO CLARENDON LINE ON
THE FAVORABLE SIDE FOR STORMS TO DEVELOP.

SO THIS LEADS TO THE OTHER FACTOR FOR SEVERE STORMS TODAY...ABILITY
TO BREAK THE CAP. AS STATED YESTERDAY...700MB TEMPS LOOK TO BE
BETWEEN 12 TO 14 C SO STORMS WILL STRUGGLE TO OVERCOME THIS
INHIBITION. BUT AS THE UPPER TROUGH MOVES CLOSER BY THE LATE
AFTERNOON/EARLY EVENING THE SYNOPTIC FORCING MAY PROVE SUFFICIENT TO
INITIATE ISOLATED THUNDERSTORMS. CONVECTIVE INDICES...MLCAPES IN THE
2000 J/KG RANGE AND BULK SHEAR OF 30-40 KT...REMAIN FAVORABLE FOR
ANY STORMS THAT FORMS TO HAVE THE POTENTIAL TO PRODUCE LARGE HAIL
AND DAMAGING WIND. THE MAIN TIME OF WHEN THESE STORMS COULD FORM
WILL BE FROM 4 PM TO 9 PM.

SUNDAY THROUGH TUESDAY WILL SEE OFF AND ON RAIN CHANCES AS SEVERAL
SHORTWAVES ROTATE AROUND THE BROAD UPPER LEVEL TROUGH. HIGH
TEMPERATURES WILL SEE A SLIGHT COOLING THANKS TO A WEAK COLD FRONT
DURING THE DAY ON SUNDAY. WEAK RIDGING WILL LEAVE WEDNESDAY VOID OF
PRECIP CHANCES BEFORE PRECIP CHANCES RETURN FOR THE END OF THE WORK
WEEK.

FIRE WEATHER...
CRITICAL FIRE WEATHER CONDITIONS ARE EXPECTED ACROSS THE WESTERN TWO
THIRDS OF THE PANHANDLES THIS AFTERNOON. RELATIVE HUMIDITY VALUES
WILL DROP TO BETWEEN 6 TO 15 PERCENT WHILE 20-FOOT WINDS INCREASE TO
20 TO 25 MPH WITH HIGHER GUSTS. ERC VALUES ARE EXPECTED TO BE IN THE
75TH TO 96TH PERCENTILE RANGE...BUT A LIMITING FACTOR ON THE
SIGNIFICANT WILD FIRE POTENTIAL WILL BE THE RECENT GREEN UP AND LACK
OF FUEL LOADING. CRITICAL FIRE WEATHER CONDITIONS WILL END OVERNIGHT
AS RELATIVE HUMIDITIES REBOUND AND WINDS LESSEN.

ELEVATED TO NEAR CRITICAL FIRE WEATHER CONDITIONS ARE POSSIBLE
SUNDAY ACROSS THE SOUTHWESTERN HALF OF THE TEXAS PANHANDLE. NEITHER
ELEVATED NOR CRITICAL FIRE WEATHER CONDITIONS ARE EXPECTED MONDAY
THROUGH THURSDAY FOR THE TEXAS AND OKLAHOMA PANHANDLE.

&&

.AMA WATCHES/WARNINGS/ADVISORIES...
TX...RED FLAG WARNING UNTIL 10 PM CDT THIS EVENING FOR THE FOLLOWING
     ZONES: ARMSTRONG...CARSON...DALLAM...DEAF SMITH...DONLEY...
     GRAY...HANSFORD...HARTLEY...HUTCHINSON...MOORE...
     OCHILTREE...OLDHAM...POTTER...RANDALL...ROBERTS...SHERMAN.

OK...RED FLAG WARNING UNTIL 10 PM CDT THIS EVENING FOR THE FOLLOWING
     ZONES: BEAVER...CIMARRON...TEXAS.


&&

$$

08/03