MESOSCALE PRECIPITATION DISCUSSION 0073
NWS WEATHER PREDICTION CENTER COLLEGE PARK MD
1016 AM EDT SUN MAY 10 2015
 
AREAS AFFECTED...CENTRAL/NORTHEAST TX, EASTERN OK, PORTIONS OF AR 
 
CONCERNING...HEAVY RAINFALL...FLASH FLOODING LIKELY 
 
VALID 101415Z - 102015Z
 
SUMMARY...A CONVECTIVE LINE AND A DRY LINE IN ITS WAKE SHOULD
SERVE AS FOCI FOR CONVECTIVE DEVELOPMENT.  SINCE SOME OF THE
EXPECTED ACTIVITY SHOULD MOVE OVER AREAS OF SATURATED SOILS, AND
HOURLY RAIN RATES UP TO 2.5" REMAIN POSSIBLE, FLASH FLOODING IS
CONSIDERED LIKELY.

DISCUSSION...THE SURFACE ANALYSIS REVEALS A DRY LINE IN
WEST-CENTRAL TX ~150 MILES WEST OF AN OUTFLOW BOUNDARY CAUSED BY A
CONVECTIVE LINE SLOWING DOWN ACROSS CENTRAL TX.  RAINFALL RATES OF
2-2.5" HAVE BEEN SEEN FROM RECENT RADAR IMAGERY WITHIN A TRAINING
BAND.  PRECIPITABLE WATER VALUES OF 1.5" EXIST PER RECENT GPS
INFORMATION. THE 850 HPA INFLOW IS IN THE RANGE OF 50-60 KTS
ACROSS SOUTH AND SOUTHEAST TX, STREAMING TOWARDS THE TAIL END OF
THE OUTFLOW BOUNDARY, NEARLY DOUBLE THE 850-400 HPA MEAN WIND. 
MIXED LAYER CAPE VALUES IN THIS AREA ARE 1000-2000 J/KG PER RECENT
SPC MESOANALYSES.  AS AN UPPER LOW MOVES NORTHWARD THROUGH THE
CENTRAL HIGH PLAINS, DIRECTIONAL WIND SHEAR IS LESSENING ACROSS
THE REGION.  INCLUDING THE IMPACT OF RECENT RAINS, THE OVERALL
ENVIRONMENT IS A NEARLY IDEAL SETUP FOR FLASH FLOODING.

THE 850 HPA INFLOW SHOULD REMAIN STEADY INTO THE REGION WITH
LITTLE MOVEMENT SEEN TO ITS AXIS WITHIN RAP FORECASTS OVER THE
NEXT SEVERAL HOURS.  INITIAL CIN NEAR SURFACE BOUNDARIES IS
EXPECTED TO ERODE OVER THE NEXT COUPLE HOURS, LEADING TO MORE
SURFACE-BASED CONVECTION.  CAPE VALUES ARE EXPECTED TO RAMP UP
INTO THE 2000-4000 J/KG RANGE, WHICH ALONG WITH A LITTLE LINGERING
DIRECTIONAL WIND SHEAR SHOULD ALLOW FOR SOME FORWARD PROPAGATION
LATER TODAY TO CONVECTION, PARTICULARLY ACROSS PORTIONS OF OK/AR,
LIKELY IN AN EAST-NORTHEAST TO NORTHEAST DIRECTION AT ~35 KTS,
SIMILAR TO THE PAST FEW DAYS AND RECENT RADAR TRENDS.  WITH AT
LEAST TWO ROUNDS OF CONVECTION POSSIBLE FOR AREAS OF TX/SOUTHEAST
OK IN A REGION WHERE BACKBUILDING AND TRAINING THUNDERSTORMS ARE
MOST PROBABLE, AND CONSIDERING  SATURATED SOILS IN THE AREA, FLASH
FLOODING IS PROBABLE OVER PORTIONS OF THIS LARGE AREA.

ROTH

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

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

LAT...LON   35859399 35849232 35369115 34289187 32799410 
            30979756 30180001 31509951 33259849 34669714 
            35529550