MESOSCALE PRECIPITATION DISCUSSION 0149...CORRECTED
NWS WEATHER PREDICTION CENTER COLLEGE PARK MD
243 PM EDT FRI APR 29 2016
 
CORRECTED FOR GRAPHICAL THREAT AREA

AREAS AFFECTED...NORTHEAST TX...SOUTHEAST OK...SOUTHERN
AR...NORTHERN LA...WESTERN/NORTHERN MS 
 
CONCERNING...HEAVY RAINFALL...FLASH FLOODING LIKELY 
 
VALID 291841Z - 292330Z
 
SUMMARY...INTENSE SHOWERS AND THUNDERSTORMS WILL CONTINUE
REPEATING AND TRAINING OVER CENTRAL/SOUTHWEST AR...BUT WILL EXPAND
IN COVERAGE AND BECOME MORE FOCUSED OVER NORTHEAST TX/NORTHERN LA
THIS AFTERNOON.

DISCUSSION...THE MCS OVER AR TODAY HAS BEGUN TO LOSE SOME
CHARACTER OVER THE LAST COUPLE OF HOURS...BUT THERE CONTINUES TO
BE A MOIST AND VERY UNSTABLE LOW LEVEL JET INTERACTING WITH A
WELL-DEFINED STATIONARY FRONT FROM NEAR THE RED RIVER EAST ACROSS
SOUTHERN AR. THIS IS RESULTING IN RENEWED CONVECTIVE DEVELOPMENT
WITH LOCALLY SIGNIFICANT TRAINING OF CELLS ACROSS ESPECIALLY
SOUTHWEST AR. ALREADY SIGNIFICANT FLASH FLOODING HAS OCCURRED HERE.

THE ENVIRONMENT SOUTH OF THE STATIONARY FRONT IS VERY UNSTABLE
WITH SBCAPE VALUES OF 3500 TO 4500 J/KG. THE HIGHER CAPE VALUES
ARE OUT ACROSS NORTHERN TX AND WITH ADDITIONAL DIABATIC WARMING
OVER THE NEXT 2 TO 3 HOURS...GREATER INSTABILITY WILL FOSTER A
MORE EXPANSIVE AREA OF CONVECTIVE INITIATION. ALREADY THE LATEST
GOES-14 SRSO VIS IMAGERY IS INDICATING AN INCREASINGLY AGITATED
CU/TCU FIELD ACROSS CENTRAL AND NORTHERN TX...AND WITH DEFINABLE
CLOUD STREETS THAT ALIGN WITH THE AFOREMENTIONED LOW LEVEL JET.

GIVEN THE DEGREE OF UPSTREAM INSTABILITY...EXPECT CONVECTION TO
RAPIDLY EXPAND IN COVERAGE OVER NORTHEAST TX AND ADJACENT AREAS OF
NORTHERN LA...WHERE CONFLUENT LOW LEVEL FLOW AND 850 MB SPEED
CONVERGENCE COUPLED WITH INCREASINGLY DIFFLUENT FLOW ALOFT
ASSOCIATED WITH A SPLIT UPPER JET STRUCTURE AHEAD OF AN UPPER LOW
HELPS FOSTER STRONG DEEP LAYER ASCENT. MEANWHILE...THIS SAME
ENERGY WILL CONTINUE TO FOCUS CONVECTION ACROSS ADJACENT AREAS
NEAR THE FRONT OVER SOUTHEAST OK AND SOUTHWEST AR AND ALSO LOCALLY
OVER WESTERN MS.

RAINFALL RATES OF UP TO 2.5 INCHES/HR ARE EXPECTED...WITH RAINFALL
TOTALS OF 3 TO 6 INCHES AND LOCALLY HEAVIER AMOUNTS LIKELY. THIS
WILL BE IN ADDITION TO EARLIER HEAVY RAINS FOR SOME LOCATIONS.
THUS...FLASH FLOODING WILL BE LIKELY.

ORRISON

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

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

LAT...LON   34999099 34948919 34688840 34098838 33468901 
            33008984 32479119 32339263 32299388 32369499 
            32629580 33069642 33559659 34079623 34359572 
            34759413 34949250