MESOSCALE PRECIPITATION DISCUSSION 0068
NWS WEATHER PREDICTION CENTER COLLEGE PARK MD
256 PM EDT SAT MAY 09 2015
 
AREAS AFFECTED...PORTIONS OF OK, NORTHEAST TX, AND AR 
 
CONCERNING...HEAVY RAINFALL...FLASH FLOODING LIKELY 
 
VALID 091855Z - 100055Z
 
SUMMARY...THUNDERSTORMS ACROSS OK AND NORTHEAST TX ARE EXPECTED TO
CONTINUE TO ORGANIZE AS THEY PROGRESS EASTWARD.  FLASH FLOODING IS
CONSIDERED LIKELY DUE TO SATURATED SOILS.

DISCUSSION...THUNDERSTORMS CONTINUE TO GROW IN SIZE AND INTENSITY
ACROSS OK AND NORTHEAST TX.  HOURLY RAIN RATES UP TO 3" AN HOUR
HAVE BEEN WITNESSED PER RADAR ESTIMATES NORTHEAST OF DALLAS IN A
TRAINING BAND.  PRECIPITABLE WATER VALUES OF 1.4-2" INHABIT THE
REGION PER RECENT GPS INFORMATION.  THUNDERSTORMS CONTINUE TO BE
FOCUSED NEAR AND NORTH OF AN OUTFLOW BOUNDARY WHICH HAS YET TO
MAKE MUCH NORTHWARD PROGRESS, WITH CAPPING ALOFT LEADING TO SOME
ELEVATION TO THE CONVECTION (HINTED AT BY THE WARM 700 HPA
TEMPERATURES).  MIXED LAYER CAPE VALUES OF 1000-3000 J/KG EXIST
ACROSS NORTHEAST TX PER THE SPC MESOANALYSIS.  VAD WIND PROFILES
INDICATE 850 HPA INFLOW OF 35-45 KTS TOWARDS THE BOUNDARY, NEAR
THE MAGNITUDE OF THE 850-400 MEAN WIND.  CONSIDERING THE SURFACE
WIND FIELD, THIS YIELDS UP TO 35 KTS OF CLOUD BASE INFLOW. 
DIRECTIONAL WIND SHEAR WITH HEIGHT COMBINED WITH THE INSTABILITY
HAS FOSTERED FORWARD PROPAGATING THUNDERSTORMS, MOVING GENERALLY
EAST TO EAST-NORTHEAST.

RECENT RAP GUIDANCE INDICATES SOME LIFTING OF THE OUTFLOW BOUNDARY
IS POSSIBLE ACROSS AR OVER THE NEXT SEVERAL HOURS.  BACKING WINDS
ACROSS CENTRAL TX COULD ALLOW FOR CONVECTION TO FORM NEAR THE WAVE
NEAR CHILDRESS, WHICH IS WHERE THE OUTFLOW BOUNDARY AND THE DRY
LINE CONVERGE.  HOURLY RAIN RATES UP TO 2.5" CONTINUE TO BE
POSSIBLE, WHICH COULD BE EVEN HIGHER WHERE CELLS MERGE.  CELL
TRAINING CONTINUES TO BE THE MAIN FLASH FLOOD RISK, WITH
BACKBUILDING CONTRIBUTING TO ISSUES ACROSS NORTHEAST TX.  THE
MESOSCALE GUIDANCE INDICATES LOCAL MAXIMA OF 3-5" WITHIN THIS
REGION.  FLASH FLOODING IS CONSIDERED LIKELY CONSIDERING SATURATED
SOILS OVER MUCH OF THE AREA.

ROTH

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

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

LAT...LON   36399470 36229265 35429111 34029115 33149207 
            32919372 33009608 33249819 33689930 34309996 
            34420003 35649791 36099624 
a