000
FXUS64 KAMA 240413 AAD
AFDAMA

AREA FORECAST DISCUSSION...UPDATED
NATIONAL WEATHER SERVICE AMARILLO TX
1113 PM CDT THU MAY 23 2013

.UPDATE...
FORECASTING HAS TO BE ONE OF THE MOST HUMBLING PROFESSIONS AROUND.
JUST WHEN YOU THINK YOU HAVE A HANDLE ON HOW THINGS WILL EVOLVE, THEY
CHANGE IN THE BLINK OF AN EYE -- OR A RADAR VOLUME SCAN. CONVECTION
MOVING ACROSS EASTERN NEW MEXICO HAS REALLY INCREASED IN INTENSITY
OVER THE LAST FEW VOLUME SCANS. IT APPEARS THAT THESE STORMS ARE
TAPPING INTO ELEVATED INSTABILITY ALOFT WITH MOST UNSTABLE CAPE
VALUES BETWEEN 1000-2000 J/KG. ADDITIONALLY, DEEP LAYER SHEAR VALUES
REMAIN AROUND 50 KT, WHICH IS VERY SUPPORTIVE OF ORGANIZED
UPDRAFTS/POSSIBLY EVEN BRIEF SUPERCELLULAR STRUCTURES. WHILE THE
ELEVATED BUOYANCY VALUES WILL REMAIN FAIRLY CONSTANT OVERNIGHT, DEEP
LAYER SHEAR VALUES WILL BE ON THE DECREASE WITH TIME AND SHOULD BE
LESS THAN 30 KT BY 3 AM. AS A RESULT, WE THINK THERE IS A WINDOW OF
OPPORTUNITY FOR SEVERE STORMS THROUGH 3 AM, MAINLY WEST OF GUYMON TO
AMARILLO LINE. THE MAIN HAZARD WITH THESE STORMS WILL BE HAIL UP TO
THE SIZE OF HALF DOLLARS. AFTER 3 AM, STORMS SHOULD REMAIN BELOW
SEVERE LEVELS, BUT HAIL UP TO THE SIZE OF NICKELS WILL STILL BE
POSSIBLE.

JACKSON

&&

.PREV DISCUSSION... /ISSUED 1035 PM CDT THU MAY 23 2013/

UPDATE...
LOWERED POPS AND MADE MINOR ADJUSTMENTS TO OTHER WEATHER ELEMENTS.

DISCUSSION...
MOST FOLKS WILL BE VERY DISAPPOINTED BY THE LACK OF RAIN THAT
OCCURRED TODAY, ESPECIALLY SINCE DEW POINTS ROSE INTO THE 60S IN
MANY AREAS. UNFORTUNATELY FOR OUR AREA, A COUPLE OF DOMINANT
SUPERCELLS DEVELOPED SOUTHEAST OF OUR FORECAST AREA THIS AFTERNOON
AND CONGEALED INTO A CONVECTIVE COMPLEX. THIS CONVECTIVE COMPLEX
GENERATED A SIGNIFICANT OUTFLOW BOUNDARY THAT RACED NORTHWESTWARD AND
CAUSED STRONG EASTERLY WINDS IN ITS WAKE. AS THIS OUTFLOW BOUNDARY
ENCOUNTERED A VERY UNSTABLE AIR MASS ACROSS THE PANHANDLES, IT
HELPED INITIATE A COUPLE OF BRIEF SUPERCELLS JUST NORTH OF AMARILLO.
HOWEVER, DUE TO QUITE A BIT OF CONVECTIVE INHIBITION AND A LACK OF
STRONGER UPPER FORCING, THESE SUPERCELLS QUICKLY DISSIPATED AS THE
OUTFLOW BOUNDARY MOVED NORTHWESTWARD AWAY FROM THE STORMS.

SHOWERS AND THUNDERSTORMS CONTINUE ACROSS THE ROLLING PLAINS AND
EASTERN NEW MEXICO. IT`S NOT OUT OF THE QUESTION THAT SOME OF THE
STORMS IN NEW MEXICO, AIDED BY THE AFOREMENTIONED OUTFLOW BOUNDARY,
COULD MAKE THEIR WAY INTO THE WESTERN PANHANDLES AFTER MIDNIGHT. AS
WE SAW EARLIER THIS EVENING, THIS ACTIVITY WILL LIKELY DECREASE IN
COVERAGE AND INTENSITY AS IT GETS FARTHER FROM THE OUTFLOW BOUNDARY.
THEREFORE, WE`RE NOT VERY OPTIMISTIC ABOUT PRECIPITATION CHANCES
OVERNIGHT, SO WE LOWERED POPS FURTHER. HOWEVER, WITH A MOIST
ATMOSPHERE IN PLACE AND A WEAK SHORTWAVE TROUGH APPROACHING FROM THE
WEST, WE`LL KEEP A MENTION FOR A SLIGHT CHANCE OF THUNDERSTORMS
OVERNIGHT. LOCATIONS WEST OF A GUYMON TO AMARILLO LINE WILL LIKELY BE
THE MOST FAVORED LOCATIONS IF STORMS DO IMPACT OUR AREA.

DUE TO BREEZY EASTERLY WINDS AND INCREASING LOW CLOUDS, TEMPERATURES
WILL BE MILD AGAIN TONIGHT. DUE TO THIS, WE WENT AHEAD AND INCREASED
LOWS A COUPLE DEGREES. WITH THE MOIST AIR MASS IN PLACE, SOME PATCHY
FOG OR EVEN DRIZZLE COULD DEVELOP AFTER 4 AM. THE PATCHY FOG
POTENTIAL IS CONDITIONAL UPON WINDS SUBSIDING UNDER 10 MPH, BUT
SINCE THIS IS UNLIKELY TO OCCUR IN MOST LOCATIONS, WE LEFT THE
MENTION OF FOG OUT OF THE FORECAST. UPDATED PRODUCTS AND
POINT-N-CLICK FORECASTS ARE UPDATED.

JACKSON

PREV DISCUSSION... /ISSUED 653 PM CDT THU MAY 23 2013/

AVIATION...
00Z TAFS...THUNDERSTORMS CONTINUE TO STRUGGLE TO DEVELOP ACROSS THE
PANHANDLES EARLY THIS EVENING...AND ADDITIONAL DEVELOPMENT LOOKS
DOUBTFUL AFTER THE ONE STORM NORTH OF KAMA DISSIPATES.

THE NEXT AVIATION CONCERN BECOMES LOW CLOUD POTENTIAL TONIGHT. HAVE
THE HIGHEST CONFIDENCE IN LOW CLOUDS AT KGUY...WHERE CIGS CONTINUE
TO BOUNCE IN AND OUT OF THE MVFR RANGE. MAY SEE A PERIOD OF VFR
CONDITIONS THIS EVENING...BUT THEN EXPECT MVFR CIGS TO TAKE HOLD
AGAIN...LIKELY LOWERING TO IFR LATE TONIGHT. VFR CONDITIONS SHOULD
RETURN AT KGUY BY MIDDAY FRIDAY. COULD SEE A PERIOD OF MVFR CIGS AT
DHT OVER THE NEXT COUPLE OF HOURS...BUT OTHERWISE WILL KEEP THINGS
VFR AT KAMA AND KDHT. THERE IS SOME POTENTIAL FOR LOW CLOUDS TONIGHT
AT THESE SITES AS WELL...BUT CONFIDENCE IS TOO LOW TO MENTION AT THIS
POINT.

GUSTY EASTERLY WINDS THIS EVENING WILL DIMINISH SOME AND VEER TO THE
SOUTH OVERNIGHT...WITH GUSTS OVER 25 KTS THEN EXPECTED AGAIN BY
FRIDAY AFTERNOON.

KB

PREV DISCUSSION... /ISSUED 317 PM CDT THU MAY 23 2013/

SHORT TERM...TONIGHT THROUGH SUNDAY.

TONIGHT...
SEVERE THUNDERSTORMS COULD BE ONGOING ACROSS THE PANHANDLES AS WE
HEAD INTO THE TONIGHT PERIOD. THE STALLED FRONT DRAPED ACROSS THE
AREA ...AND A DRY LINE INTERSECTING THIS FRONT FROM THE SOUTH...WILL
CONTINUE TO SERVE AS THE MAIN FOCUSES FOR CONVECTION. THEREFORE THE
SOUTHEASTERN TEXAS PANHANDLE WILL HAVE THE GREATEST CHANCES FOR
SEVERE WEATHER. ELSEWHERE ACROSS THE PANHANDLES...ISOLATED SHOWERS
AND THUNDERSTORMS WILL STILL BE POSSIBLE. WITH SLOW STORM MOTIONS
AND PWAT VALUES AT LEAST IN THE 75TH PERCENTILE RANGE MOVING INTO
THE AREA...LOCALIZED FLASH FLOODING CAN BE EXPECTED.

FRIDAY AND SATURDAY...
THE OVERALL THREAT FOR ORGANIZED SEVERE WEATHER WILL BE DECREASING
OVER THE WEEKEND. AT THIS TIME...CONFIDENCE REMAINS LOW AS TO THE
EXACT PLACEMENT FOR PRECIPITATION...AS OUTFLOW BOUNDARIES FROM
TODAY/S CONVECTION WILL ALMOST CERTAINLY PLAY A ROLE IN THE COMING
DAYS. IN GENERAL...THE WESTERN PANHANDLES WILL BE FAVORED...WITH
1500-2500 J/KG OF MLCAPE MAINLY IN THE WEST. A TALL AND SKINNY CAPE
PROFILE AND SLOW STORM MOTIONS WILL FAVOR MORE OF A HEAVY RAIN
THREAT THAN LARGE HAIL OR TORNADO THREAT.

SUNDAY...
THE DRYLINE ON SUNDAY SHOULD PUSH A LITTLE FURTHER EAST...SETTING UP
MORE LIKELY NEAR OR EAST OF AMARILLO. AGAIN...1500-2500 J/KG OF
MLCAPE AND A TALLER SKINNY CAPE PROFILE SUGGEST A HIGH RISK FOR
HEAVY RAIN.

NF

LONG TERM...SUNDAY EVENING THROUGH NEXT THURSDAY.

A FAIRLY ACTIVE PATTERN IS EXPECTED TO PERSIST THROUGH MID TO LATE
NEXT WEEK...WITH AT LEAST SOME CHANCE FOR A FEW THUNDERSTORMS
ASSOCIATED WITH THE DRYLINE EVERY AFTERNOON AND EVENING.

A SOUTHWEST FLOW ALOFT WILL PERSIST ACROSS THE HIGH PLAINS THROUGH
MUCH OF NEXT WEEK...AS THE REGION REMAINS STATIONED BETWEEN AN UPPER
TROUGH ACROSS THE WESTERN CONUS AND AN UPPER RIDGE AXIS OVER THE
EASTERN PLAINS STATES/MS VALLEY. THIS UPPER FLOW PATTERN WILL
MAINTAIN PERSISTENT LEE SURFACE TROUGHING...AND ALSO KEEP THE
DRYLINE FROM MIXING TOO FAR EAST. THE DRYLINE WILL LIKELY MIX FROM
EASTERN NM INTO THE WESTERN PANHANDLES EACH DAY...POSSIBLY HANGING
UP IN EASTERN NM ON A COUPLE DAYS...PROVIDING A DAILY FOCUS FOR AT
LEAST A FEW STORMS TO DEVELOP. ANY WEAK SHORTWAVES EJECTING IN THE
SOUTHWEST FLOW ALOFT WILL ENHANCE STORM CHANCES ON A GIVEN DAY.
MODELS CONTINUE TO DIFFER WITH THE EVENTUAL EJECTION OF THE MAIN
WESTERN TROUGH...WITH THE GFS MORE PROGRESSIVE THAN THE ECMWF. HAVE
TRENDED MORE CLOSELY TO THE LESS PROGRESSIVE ECMWF FOR NOW. DEEP
LAYER SHEAR LOOKS TO BE MODEST ON MOST DAYS...LIKELY INCREASING
LATER IN THE WEEK WHEN THE TROUGH DOES EVENTUALLY EJECT.
HOWEVER...LOW-LEVEL MOISTURE HANGING IN EAST OF THE DRYLINE WILL
MAINTAIN SUFFICIENT INSTABILITY TO SUPPORT SOME THREAT OF A FEW
SEVERE STORMS EACH AFTERNOON AND EVENING. LARGE HAIL AND DAMAGING
WINDS WILL BE THE PRIMARY THREATS WITH THESE STORMS.

TEMPERATURES WILL GENERALLY REMAIN ABOVE AVERAGE THROUGH THE PERIOD
WITH HIGHS REACHING THE MID 80S TO LOWER 90S AND LOWS IN THE MID 50S
TO UPPER 60S.

KB

FIRE WEATHER...
NO ELEVATED OR CRITICAL FIRE WEATHER CONDITIONS ARE EXPECTED THROUGH
THE NEXT WEEK AS RAIN CHANCES REMAIN IN THE FORECAST.

&&

.AMA WATCHES/WARNINGS/ADVISORIES...
TX...NONE.
OK...NONE.

&&

$$

JC/JJ