MESOSCALE PRECIPITATION DISCUSSION 0277
NWS WEATHER PREDICTION CENTER COLLEGE PARK MD
410 PM EDT SUN OCT 13 2013
 
AREAS AFFECTED...RIO GRANDE VALLEY INTO CENTRAL TEXAS 
 
CONCERNING...HEAVY RAINFALL...FLASH FLOODING LIKELY 
 
VALID 132010Z - 140210Z
 
SUMMARY...HEAVY RAIN IS EXPECTED TO CONTINUE JUST NORTH OF AN
OUTFLOW BOUNDARY ACROSS SOUTHWESTERN TEXAS FOR THE NEXT FEW HOURS
ON TOP OF ALREADY SATURATED SOILS...WHICH WILL PROLONG THE FLASH
FLOOD THREAT INTO THE EVENING.

DISCUSSION...19Z SURFACE ANALYSIS SHOWED A WELL DEFINED OUTFLOW
BOUNDARY BETWEEN LRD AND COT...EXTENDING EAST TOWARD MATAGORDA
BAY...WITH LITTLE TO NO MOVEMENT SEEN OVER THE PAST COUPLE OF
HOURS. A CONVECTIVE CLUSTER HAS BEEN ONGOING SINCE THE EARLY
MORNING ACROSS THE REGION WITH REPORTS OF 6-10+ INCHES OF RAIN PER
RECENT LSR REPORTS NEAR CRYSTAL CITY. VERY EFFICIENT RAINFALL
RATES AVERAGING 1-2 IN/HR SINCE ABOUT 12Z HAVE OCCURRED...COURTESY
OF PRECIPITABLE WATER VALUES BETWEEN 2.00-2.25 IN PER RECENT
BLENDED TPW IMAGERY AND ADDED UPPER LEVEL MOISTURE DOWNWIND OF
T.S. OCTAVE LOCATED IN THE EASTERN PACIFIC...JUST SOUTHWEST OF THE
BAJA PENINSULA. 1000-3000 J/KG MIXED LAYER CAPE CONTINUES TO BE
PRESENT TO THE SOUTH OF THE OUTFLOW BOUNDARY OVER EXTREME SOUTH
TEXAS...AIDED BY DEWPOINTS IN THE LOW TO MID 70S AND MOSTLY SUNNY
SKIES.


WITH 850 MB FLOW FROM THE SOUTHEAST AT 20-30 KTS PER KDFX VAD WIND
PROFILE...AND THE RAP CONTINUING TO SHOW THIS AS BEING UNCHANGED
THROUGH 00Z...CONVECTION IS EXPECTED TO PERSIST WELL INTO THE
EVENING...AND PERHAPS SHIFTING EAST A BIT WITH THE MEAN FLOW.
ONGOING CONVECTION OVER THE THREAT AREA MAY IMPEDE BETTER MOISTURE
RETURN AND CONVECTIVE RAINS FARTHER NORTH AT LEAST IN THE SHORT
TERM...UNTIL THE APPROACH OF A LARGE SHORTWAVE TROUGH CURRENTLY
SLIDING EAST FROM THE GREAT BASIN WHICH SHOULD ALLOW LOW LEVEL
WINDS TO VEER TONIGHT. UNTIL THEN...EXPECT CONTINUED RAINFALL
RATES OF 2-3 IN/HR ON A LOCALIZED BASIS WITH CONTINUED RUNOFF
ISSUES.

OTTO

ATTN...WFO...CRP...EWX...SJT...

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

LAT...LON   29990137 31410043 31009870 29789775 28679753 27749794
            27389962 28540085 29990137