000
FXUS64 KAMA 250503 AAC
AFDAMA

AREA FORECAST DISCUSSION...UPDATED
NATIONAL WEATHER SERVICE AMARILLO TX
1203 AM CDT SAT MAY 25 2013

.AVIATION.../06Z TAFS/
TSRA IS LIKELY TO IMPACT KGUY THROUGH 09Z WITH BRIEF IFR CONDITIONS
AND GUSTY WINDS TO 35 KT. THERE`S AN OUTSIDE CHANCE KDHT MAY SEE VCSH
07Z-08Z, BUT CONFIDENCE IS TOO LOW TO MENTION.

ANOTHER ROUND OF TSRA COULD DEVELOP LATE SATURDAY AFTERNOON ACROSS
EASTERN NEW MEXICO, AND THESE COULD MAKE A RUN AT THE TERMINALS AFTER
02Z, BUT THERE IS ENOUGH UNCERTAINTY IN THIS SCENARIO THAT WE DIDN`T
MENTION ANYTHING IN THIS TAF ISSUANCE.

HAVE MODERATE TO HIGH CONFIDENCE OF IFR CONDITIONS AT KAMA 09Z-16Z.
THERE IS A CHANCE OF MVFR CONDITIONS AT KDHT AND KGUY 09Z-15Z, BUT
WILL NOT MENTION SINCE THE CURRENT SHOWERS AND STORMS MAY DISRUPT
THIS POTENTIAL.

JACKSON

&&

.PREV DISCUSSION... /ISSUED 920 PM CDT FRI MAY 24 2013/

UPDATE...
HAVE UPDATED GRAPHICAL PRODUCTS...CALLING FOR HIGHER COVERAGE OF
THUNDERSTORMS THIS EVENING ACROSS NORTHWESTERN PART OF FORECAST AREA.
THIS LOCATION MARKED BY STRONGER SOUTHWEST FLOW ALOFT...WITH ONE OR
MORE SHORTWAVE TROFS POSITIONED TO PASS OVER ZONE OF HIGHER ELEVATED
INSTABILITY.  NO OTHER CHANGES AT THIS TIME.  UPDATED TEXT PRODUCTS
WILL BE ISSUED SHORTLY.

COCKRELL

PREV DISCUSSION... /ISSUED 650 PM CDT FRI MAY 24 2013/

AVIATION.../00Z TAFS/
HAVE MODERATE TO HIGH CONFIDENCE OF IFR CONDITIONS AT KAMA 10Z-15Z,
WITH MODERATE CONFIDENCE ON TIMING. THERE IS ALSO A SMALL CHANCE FOR
MVFR CIGS DEVELOPING AT KGUY 11Z-15Z. OUTSIDE OF ANY POSSIBLE STORMS,
VFR CONDITIONS SHOULD PREVAIL AT KDHT.

HAVE MODERATE CONFIDENCE THAT -TSRA WILL BE CLOSE TO KDHT, BUT
CONFIDENCE OF A DIRECT IMPACT IS LOW. THEREFORE, WE ONLY MENTIONED
VCTS 03Z-05Z, BUT CONFIDENCE ON TIMING IS LOW TO MODERATE. IF A
-TSRA DIRECTLY IMPACTS KDHT, BRIEF GUSTY WINDS UP TO 45 KT AND BRIEF
IFR CONDITIONS WILL BE POSSIBLE. THERE IS ALSO A SMALL CHANCE KGUY
COULD BE IMPACTED BY -TSRA 04Z-06Z, BUT CONFIDENCE OF OCCURRENCE IS
TOO LOW TO MENTION.

JACKSON

PREV DISCUSSION... /ISSUED 353 PM CDT FRI MAY 24 2013/

DISCUSSION...
CONVECTION HAS BEEN SLOW TO DEVELOP TODAY BASED ON SIGNIFICANT LOW
LEVEL CAPPING. WITH THAT SAID PARTS OF THE EXTREME NORTHWESTERN
TEXAS PANHANDLE AND WESTERN OKLAHOMA PANHANDLE LOOK TO BE THE AREA
WHERE IF...BIG IF...STORMS DEVELOP THEY COULD BECOME STRONG TO
SEVERE. AS SEEN YESTERDAY...A STRONG LOW LEVEL CAP...AROUND 100 MB
DEEP FROM MODEL SOUNDINGS...WILL BE A MAJOR HURDLE ANY CONVECTION
WILL HAVE TO OVERCOME FIRST AND FOREMOST. IF THE STORMS CAN BREAK
THIS CAP THEY WILL BE FED BY AMPLE ELEVATED CAPE...1500-2000
J/KG...IN A AREA OF 20 TO 25 KT DEEP LAYER SHEAR. GIVEN THESE
INDICES HAIL UP TO HALF DOLLAR SIZE HAIL AND DAMAGING WINDS IN
EXCESS OF 60 MPH WOULD BE THE MAIN HAZARDS. GIVEN THE LACK OF
SUFFICIENT SYNOPTIC FORCING ANY STORMS THAT COULD FORM WILL BE HARD
PRESSED TO PERSIST AFTER SUNSET. CONFIDENCE IS LOW ON THESE STORMS
DEVELOPING...BUT NOT OFF THE TABLE.

THE RIDGE AXIS WILL BE EAST OF THE PANHANDLES FOR THE HOLIDAY
WEEKEND. THIS WILL KEEP LOW END PRECIP CHANCES IN THE FORECAST
THROUGH MONDAY. WEAK DEEP LAYER SHEAR...MARGINAL ELEVATED
INSTABILITY...AND A DEEP LOW LEVEL CAP SHOULD KEEP ORGANIZED
CONVECTION TO A MINIMUM SHOULD ANY STORMS DEVELOP. AS WITH TODAY IF
STORMS CAN OVERCOME THE CAP...AND IF THEY CAN TAP INTO THE ELEVATED
INSTABILITY THEN STRONG TO SEVERE STORMS COULD HAPPEN. THE MAIN
HAZARDS FROM ANY STORM THAT CAN DO THIS WOULD BE DAMAGING WINDS AND
LARGE HAIL.

TOWARDS THE LATER HALF OF NEXT WEEK A BROAD UPPER LOW WILL ROTATE
THROUGH THE FOUR CORNER REGION AN COULD BRING A ROUND OF ORGANIZED
SEVERE WEATHER. NOW THE DISCLAIMER...THIS IS STILL SEVERAL DAYS OUT
AND MODELS HAVE A WIDE VARIATION ON TIMING AND TRACK OF THE UPPER
LOW. IF THE TRACK GOES FURTHER NORTH THAN SHOWN THEN WE GET JUST THE
TAIL END OF ANY CONVECTION. THE ECMWF HAS THE MOST FAVORABLE TRACK
FOR A SEVERE WEATHER OUTBREAK BY DIGGING THE LOW INTO ARIZONA/NEW
MEXICO THEN EJECTING TO THE NORTHEAST...CAUSING THE LOW TO TAKE ON
A NEGATIVE TILT. THIS SYNOPTIC LIFT COMBINED WITH 1500-2000 J/KG AND
30-40 KT DEEP SHEAR COULD LEAD TO WIDESPREAD ORGANIZED CONVECTION.
ON THE OTHER HAND THE GFS DOES NOT DIG THIS LOW AS DEEP. INSTABILITY
VALUES LOOK SIMILAR TO THE ECMWF BUT WITHOUT THE SYNOPTIC FORCING
ANY CONVECTION THAT FORMS MAY BE LIMITED ON ITS SEVERITY POTENTIAL.
KEEP AN EYE ON THIS PORTION OF THE FORECAST AND EXPECT CHANGES AS WE
MOVE CLOSER.

FIRE WEATHER...
NEITHER ELEVATED NOR CRITICAL FIRE WEATHER CONDITIONS ARE EXPECTED
FOR THE NEXT SEVERAL DAYS.

&&

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

&&

$$

JJ/JC