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000
FXUS64 KMAF 132330
AFDMAF

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE MIDLAND/ODESSA TX
630 PM CDT THU JUN 13 2013

.DISCUSSION...

SEE 00Z AVIATION DISCUSSION BELOW.

&&

.AVIATION...

SCATTERED SHOWERS AND THUNDERSTORMS WILL CONTINUE ACROSS THE AREA
FOR THE NEXT COUPLE OF HOURS. THE STORMS MAY AFFECT THE TERMINALS
WITH MAF HAVING THE HIGHEST PROBABILITY. GUSTY SOUTHEAST WINDS
WILL GRADUALLY DECREASE INTO THE EVENING AND OVERNIGHT HOURS. MORE
RAIN AND THUNDERSTORMS ARE EXPECTED TO DEVELOP FRIDAY MORNING AND
CONTINUE THROUGH THE AFTERNOON HOURS. UNCERTAIN AS TO WHETHER ANY
TERMINALS WILL BE AFFECTED SO INCLUDED PROB30 GROUPS FOR NOW. MVFR
TO IFR CEILINGS WILL BE LIKELY FRIDAY MORNING WITH ONLY SLIGHT
IMPROVEMENT FOR THE LATE MORNING TO AFTERNOON HOURS.

&&

.PREV DISCUSSION... /ISSUED 525 PM CDT THU JUN 13 2013/

DISCUSSION...

AN UNSETTLED AND (HOPEFULLY) WET PATTERN IS SHAPING UP OVER WEST
TEXAS AND SOUTHEASTERN NEW MEXICO. ABUNDANT MOISTURE THROUGH A
LARGE PORTION OF THE TROPOSPHERE IS BEING BROUGHT OVER THE
SOUTHERN HIGH PLAINS IN ADVANCE OF AN UPPER LEVEL DISTURBANCE NOW
CENTERED OVER NORTHERN COAHUILA. A SECONDARY SHORTWAVE, PERHAPS
CONVECTIVELY INDUCED, APPEARS TO BE LOCATED OVER NORTHWESTERN
CHIHUAHUA SOUTHWEST OF PRESIDIO. ALONG WITH DIURNAL HEATING, DEEP
LAYER LIFT INDUCED BY THESE DISTURBANCES HAS ACTED ON THIS MOISTURE
WITH THE NET EFFECT BEING SCATTERED TO NUMEROUS THUNDERSTORMS FROM
THE DAVIS MOUNTAINS SOUTH ACROSS THE MARFA PLAINS AND THE BIG BEND.
BOTH DEEP LAYER SHEAR AND POTENTIAL INSTABILITY ARE WEAK, AND SO
WE`RE NOT EXPECTING A SIGNIFICANT SEVERE THREAT FROM THIS ACTIVITY.
HOWEVER, BECAUSE THE CELLS ARE MOVING SLOWLY AND WITHIN A RICH
AIRMASS, LOCALIZED FLOODING WILL BE A CONCERN THROUGH MID EVENING,
ESPECIALLY IN ARROYOS, DRAWS, LOW WATER CROSSINGS, ETC. THUNDERSTORM
ACTIVITY MAY PERSIST OVERNIGHT GENERALLY SOUTH OF I-10, ESPECIALLY
ALONG THE RIO GRANDE WHERE UPPER LEVEL FORCING IS GREATEST.

FRIDAY COULD BE THE WETTEST DAY WE`VE SEEN IN A LONG WHILE. WE
EXPECT AN AXIS OF MOISTURE TO BE ROUGHLY ALONG A SANDERSON TO
MIDLAND TO LOVINGTON LINE BY MORNING. PRECIPITABLE WATER VALUES
WITHIN THIS AXIS COULD BE OVER 4 CM, OR ABOUT AT THE 99TH PERCENTILE
OF CLIMO THIS TIME OF YEAR. WEAK DEEP LAYER SHEAR, TALL/SKINNY CAPE,
AND A DEEP WARM CLOUD LAYER ALL SUPPORT EFFICIENT RAIN PRODUCTION.
PLUS IT WON`T TAKE A LOT OF HEATING TO KICK THINGS OFF IN THE MORNING.
WHILE THE OVERALL SETUP FAVORS HEAVY RAINFALL, WE DON`T HAVE A LOT
OF CONFIDENCE IN EXACTLY WHERE THIS HEAVY RAINFALL WILL FOCUS.
SHOULD WE GET A BETTER UNDERSTANDING OF WHERE HEAVY RAINFALL WILL
FOCUS, A FLASH FLOOD WATCH COULD BE NEEDED.

RAIN CHANCES WILL CONTINUE FRIDAY NIGHT BUT WILL BEGIN TO DIMINISH
LATE IN THE EVENING AS BOTH UPPER LEVEL SUPPORT AND DIURNAL HEATING
WANE. THERE`LL BE SUFFICIENT MOISTURE AND HEATING SATURDAY FOR AT
LEAST A SLIGHT CHANCE OF THUNDERSTORMS, BUT WE SHOULD START TO DRY
OUT SATURDAY NIGHT. UPPER LEVEL RIDGING AND THICKNESSES INCREASE
SUNDAY AND THIS IN TURN WILL RESULT IN WARMER HIGHS, WITH TEMPERATURES
POSSIBLY TOPPING THE CENTURY MARK ACROSS THE UPPER TRANS PECOS.
COULD SEE COOLER TEMPERATURES ACROSS AREAS WHERE HEAVIER RAINS
OCCURRED, BUT IT COULD ALSO BE THE GROUND WILL SOAK UP WHATEVER
MOISTURE WE MIGHT GET. MODELS ARE HINTING AT MCS DEVELOPMENT OVER
KANSAS AND OKLAHOMA SUNDAY NIGHT INTO MONDAY, AND IN TURN AN OUTFLOW
BOUNDARY OF SORTS LOOKS TO ENTER WEST TEXAS SOMETIME LATE MONDAY.
TOO MANY UNCERTAINTIES RIGHT NOW TO CONTEMPLATE AND SO WE`LL LEAVE
ISOLATED THUNDER IN THE FORECAST...THIS COULD BE INCREASED AS WE
GAIN CONFIDENCE IN HOW THINGS WILL EVOLVE.

GETTING INTO THE WEEDS...A BLEND OF THE 12Z ECMWF AND 12Z NAM WAS
USED FOR THE POP/QPF FORECASTS. THE SREF APPEARS TO SUPPORT THIS
SOMEWHAT, BUT BECAUSE THE SREF IS AN ENSEMBLE, POP/QPF FORECASTS
ARE UNDERDISPERSIVE AND GET SMEARED OUT OVER A LARGER AREA. ALL
OTHER FORECAST GRIDS LOOKED PRETTY GOOD AND ONLY A FEW TWEAKS WERE
NEEDED. AS MENTIONED BEFORE, THE EVOLUTION OF MCS ACTIVITY AND
RESULTANT OUTFLOW BOUNDARY PROGRESSION MONDAY NIGHT AND TUESDAY IS
UNCERTAIN AT THIS TIME AND POP/QPF FORECASTS MAY NEED TO BE ADJUSTED
UPWARD BY LATER SHIFTS.

&&

.MAF WATCHES/WARNINGS/ADVISORIES...
NM...NONE.
TX...NONE.

&&

$$

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