Graphic for MPD #0675
MESOSCALE PRECIPITATION DISCUSSION 0675
NWS WEATHER PREDICTION CENTER COLLEGE PARK MD
856 PM EDT SAT AUG 12 2017

AREAS AFFECTED...SOUTHEAST OK...SOUTHWEST AR...NORTHEAST TX...EXT
NORTHWEST LA

CONCERNING...HEAVY RAINFALL...FLASH FLOODING LIKELY

VALID 130100Z - 130600Z

SUMMARY...UPSCALE GROWTH OF MCS STARTING TO EVOLVE WITH
STRENGTHENING LOW LEVEL JET THROUGH EARLY OVERNIGHT CROSSING
SATURATED SOILS CONTINUING TO POSE LIKELY FLASH FLOODING.

DISCUSSION...EXPERIMENTAL GOES-16 WV SUITE DEPICTS THE COMPACT
SHORTWAVE ACROSS W OK HAS SHEARED A BIT ACROSS THE STATE EXTENDING
FROM NE OK THROUGH TO NORTHWEST TX/ROLLING PLAINS WITH CONTINUED
RIGHT ENTRANCE SUPPORT OF 3H JET ACROSS SE KS/SW MO.  LOW LEVEL
SUPPORT HAS BEEN LACKING OVER THE EVENING HOURS WITH LIMITED FLOW
LEADING TO SCATTERED DISORGANIZED CLUSTERS OF THUNDERSTORMS IN THE
VICINITY OF THE SURFACE FRONT.  THIS FRONT ENHANCED BY
DIFFERENTIAL HEATING EXTENDS FROM AQV TO CRS TO GDJ AND N OF SJT
WITH WEAK SFC REFLECTIONS ALONG IT.  CELLS NORTH OF THE BOUNDARY
ARE TREATED TO A DEEPER MIXED MOISTURE SOURCE WITH TPWS NEAR OR
ABOVE 2.25" THOUGH GENTLER LAPSE RATES FURTHER NORTH AND LACK OF
HEATING OF THE LOW LEVELS SUPPORT VERY LIMITED MUCAPES (00Z OUN
RAOB)...WITH ONE EXCEPTION ACROSS ARKLATEX AND SE OK...ALSO
RESPONDING WITH AN INVERTED SURFACE TROF FROM CRS TO DEQ.  AS SUCH
THE ENVIRONMENT ALONG/SOUTH OF THE RED RIVER AS WELL AS THE
OUACHITA MTN REGION APPEAR PRIMED FOR CONVECTIVE EXPANSION.  

RAPID REFRESH GUIDANCE SUCH AS THE HRRR/ESRL HRRRV3 AND RAP
SUPPORT STRENGTHENING SWLY LLJ FROM 03-05Z INCREASING ISENTROPIC
ASCENT AND WITH SELY FLOW CONVERGING THROUGH THE TROWAL/INVERTED
SFC TROF...MST CONVERGENCE AND SLOW CELL MOTIONS/UPSTREAM
PROPAGATION VECTORS WILL ONLY FURTHER EXACERBATE CONVECTION
CAPABLE OF 2-2.5"/HR RATES AND SUPPORT POCKETS OF 3-5" TOTALS
THROUGH 06Z (TO BE FURTHER INCREASED AFTER 06Z).  WHILE FFG VALUES
HAVE REBOUNDED THIS SEEMS QUITE INFLATED AS SOILS ARE SATURATED
PER AHPS 7 DAY ANOMALIES OVER 500% OF NORMAL (3-4 INCHES) MAINLY
NORTHEAST OF METRO DFW ACROSS NE TX/SE OK/SW AR.   AS SUCH THESE
EXPECTED TOTALS WITH ANTECEDENT CONDITIONS WARRANT LIKELY FLASH
FLOODING PROBABILITIES.  

GALLINA

ATTN...WFO...FWD...LZK...OUN...SHV...TSA...

ATTN...RFC...ABRFC...LMRFC...WGRFC...

LAT...LON   34899530 34789448 34309367 33639360 32849370
            32089416 32049548 32379756 32479817 32889847
            33409814 34149749 34589636


Last Updated: 856 PM EDT SAT AUG 12 2017