MESOSCALE PRECIPITATION DISCUSSION 0237
NWS WEATHER PREDICTION CENTER COLLEGE PARK MD
823 PM EDT WED JUN 17 2015
 
AREAS AFFECTED...SOUTHEAST TEXAS...WESTERN LOUISIANA 
 
CONCERNING...HEAVY RAINFALL...FLASH FLOODING LIKELY 
 
VALID 180023Z - 180423Z
 
SUMMARY...FEW MORE HOURS OF CONTINUED COASTAL DEVELOPMENT TRAINING
OVER AREAS ALREADY HIGHLY IMPACTED BY SIGNIFICANT RAINFALL
TOTALS... 

DISCUSSION...RECENT VISIBLE/RADAR IMAGERY SHOWS UPTICK OF
CONVECTIVE GROWTH ALONG THE SOUTHEAST TEXAS COAST IN RESPONSE TO
INCREASING SURFACE/LOW LEVEL CONVERGENCE WITH 20-25KTS OF ONSHORE
FLOW.  ENVIRONMENTAL PARAMETERS REMAIN VERY MOIST AND UNSTABLE
WITH 3000-4000 J/KG ANALYZED JUST OFFSHORE.  THIS SHOULD CONTINUE
TO SUPPORT RATES IN THE 1.5-2"/HR RANGE.   THE ORIENTATION OF THE
ONSHORE FLOW REMAINS NEARLY UNIDIRECTIONAL TO SUPPORT CONTINUED
TRAINING ACROSS SOUTHEAST TEXAS COUNTIES FOR THE NEXT 2-4 HOURS. 
PERSISTENT SOUTHERLY FLOW IS FORECAST TO CONTINUE THROUGH MUCH OF
THE LATE EVENING/EARLY MORNING HOURS. IF THIS TREND CONTINUES...
RAP ANALYSIS FIELDS ALONG WITH BLENDED TPW SHOWS DRYING LOW LEVELS
ACROSS THE NORTH CENTRAL GULF OF MEXICO...THAT SHOULD BE ADVECTING
ACROSS THE AREA WITHIN THE NEXT FEW HOURS.  THE EXACT TIMING IS
CRITICAL TO REDUCE THE MOISTURE CONVERGENCE TO MAINTAIN THESE
CELLS. CONFIDENCE IN THIS TIMING IS NOT VERY HIGH GIVEN THAT MOST
OF THE HI-RESOLUTION CONVECTIVE ALLOWING MODELS HAD STARTED THE
DRYING PROCESS BY 00Z...WHICH IS CLEARLY NOT OCCURRING.  ONLY THE
RECENT HRRR SHOWS SOME CONTINUED ELEMENTS THROUGH 04-05Z.  CURRENT
THINKING IS AN ADDITIONAL 2-3 HOURS WILL EXACERBATE FLOODED
GROUNDS WITH A POTENTIAL 2-3" TOTALS...

GALLINA

ATTN...WFO...HGX...LCH...SHV...

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

LAT...LON   31989259 31429237 30689292 29789352 29289451 
            28919556 30039524 31099431 31759346