MESOSCALE PRECIPITATION DISCUSSION 0274
NWS WEATHER PREDICTION CENTER COLLEGE PARK MD
107 PM EDT TUE MAY 31 2016
AREAS AFFECTED...CENTRAL/NORTHERN TX...FAR SOUTHERN OK
CONCERNING...HEAVY RAINFALL...FLASH FLOODING LIKELY
VALID 311700Z - 312300Z
SUMMARY...VERY HEAVY SHOWERS AND THUNDERSTORMS WILL EXPAND IN
COVERAGE THIS AFTERNOON. THE INTENSE RAINFALL RATES AND SLOW CELL
MOTION WILL PROMOTE FLASH FLOODING.
DISCUSSION...CLUSTERS OF COLD-TOPPED CONVECTION ARE DEVELOPING AND
EXPANDING COVERAGE ACROSS A LARGE PORTION OF TEXAS...STRETCHING
FROM THE HILL COUNTRY NORTH TO RED RIVER. ALREADY SEEING NUMEROUS
OVERSHOOTING TOPS AS PER THE GOES-OTD ALGORITHM...AND THE
CONVECTION IS DEVELOPING IN RESPONSIVE TO A SHORTWAVE TROUGH
ENTERING WEST TX...AS DEPICTED BY A 0856Z AQUA-MODIS PASS...AND
WELL AHEAD OF AN UPPER LOW THAT IS FOCUSED ACROSS THE SOUTHWEST.
THE SHORTWAVE ENERGY IS FOCUSING A BROADLY DIVERGENT FLOW PATTERN
ALOFT ACROSS MUCH OF CENTRAL AND NORTHERN TX CURRENTLY...AND IS
INTERACTING WITH A WELL-DEFINED N/S AXIS OF MODERATE TO STRONG
SURFACE-BASED INSTABILITY.
RAP ANALYSES SHOW SBCAPE VALUES OF 3000 TO 4000 J/KG AND PWATS OF
1.5 TO 1.6 INCHES...WHICH COUPLED TOGETHER WILL BE FAVORING
INTENSE RAINFALL RATES THIS AFTERNOON THAT SHOULD BE ON THE ORDER
OF 2 TO 2.5 INCHES/HR. THIS MOISTURE AND INSTABILITY FEED WILL BE
REINFORCED THROUGH THE AFTERNOON BY ADDITIONAL DIURNAL HEATING AND
A MOIST SOUTHERLY LOW LEVEL FETCH.
THE 12Z ARW AND 12Z NMMB BOTH INDICATE A WIDESPREAD AREA OF
SCATTERED THUNDERSTORMS THROUGH THIS AFTERNOON...BUT OVERALL MAY
BE UNDERDOING THE CONVECTIVE ORGANIZATION AND COVERAGE BASED ON
THE LATEST RADAR TRENDS. THE EXPECTATION IS FOR CONVECTION TO
CONTINUE TO ORGANIZE AND INTENSIFY A BIT MORE THROUGH MID TO LATE
AFTERNOON AS STRONG INSTABILITY FOCUSES SOUTH OF THE RED RIVER AND
DOWN THROUGH THE TX HILL COUNTRY. SEVERAL AREAS OF CELL-MERGERS
AND OVERSHOOTING TOPS CAN BE EXPECTED WHICH WILL ENHANCE THE
RAINFALL RATES FURTHER.
THE GENERAL THINKING IS THAT THE HIRES GUIDANCE IS UNDERDONE WITH
THEIR AMOUNTS IN THE SHORT-TERM. BASED ON THE LATEST SATELLITE AND
RADAR TRENDS...EXPECT RAINFALL POTENTIAL THROUGH 23Z OF 3 TO 6
INCHES...WITH LOCALLY HEAVIER AMOUNTS WHERE MERGING CLUSTERS OF
CONVECTION OCCUR. GIVEN THE LOCALLY WET ANTECEDENT
CONDITIONS...FLASH FLOODING IS LIKELY.
ORRISON
ATTN...WFO...EWX...FWD...OUN...SJT...
Carla/Alicia/Jerry(In The Eye)/Michelle/Charley/Ivan/Dennis/Katrina/Rita/Wilma/Humberto/Ike/Harvey
Member: National Weather Association
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