MESOSCALE PRECIPITATION DISCUSSION 0661
NWS WEATHER PREDICTION CENTER COLLEGE PARK MD
1055 PM EST THU NOV 26 2015
 
AREAS AFFECTED...NORTH CENTRAL TEXAS 
 
CONCERNING...HEAVY RAINFALL...FLASH FLOODING POSSIBLE 
 
VALID 270344Z - 270944Z
 
SUMMARY...INITIAL ROUND OF MDT RAINS OF 1-3" WITH THE LIKELIHOOD
OF ADDITIONAL REGENERATION NEAR OR UPSTREAM LEADING TO A PROLONGED
TRAINING EVENT CAPABLE OF FLOODING POSSIBLY FLASHY OVER NEXT FEW
HOURS.

DISCUSSION...WV/IR LOOP INDICATE STRONG 110+ KT POLAR JET AND WELL
DEFINED SUBTROPICAL JET ENHANCED BY OUTFLOW CHANNEL OF HURRICANE
SANDRA CONVERGING OVER WEST TEXAS BUT BECOMING DIFFLUENT NEAR 100W
SETTING UP AN IDEAL ENVIRONMENT TO SUPPORT STRONG SYNOPTIC ASCENT
WHILE ALSO SUPPORTING THE POTENTIAL FOR BACKBUILDING/REGENERATION
OF CONVECTION TOWARD THE APEX OF THE DIFFLUENCE.  SHORTWAVE
RIDGING UPSTREAM IN THE POLAR CHANNEL AND NO REAL SHIFT IN THE
SUBTROPICAL JET SUPPORTS THIS REGIME TO MAINTAIN LOCATION FOR THE
DURATION OF THE OVERNIGHT HOURS.  WELL DEFINED COLD FRONT
CONTINUES TO DROP SOUTH ACROSS OK INTO N CENTRAL TX WHICH WILL
PROVIDE A FOCUS FOR STRONG MOISTURE CONVERGENCE FROM 35-45 KT
SOUTHERLY LOW LEVEL JET.  AT THIS TIME... RAP ANALYSIS INDICATES A
SMALL AMOUNT OF INSTABILITY WITH NEARLY UNCAPPED 750-1000 J/KG
SBCAPE NEAR THE APEX OF THE DIFFLUENT FLOW ALOFT.  RECENT IR AND
RADAR TRENDS INDICATE SOME CONVECTIVE DEVELOPMENT IS
OCCURRING...WHICH APPEARED TO BE INITIALIZED BY AN ENHANCED SPEED
MAX OUT OF THE SUBTROPICAL OUTFLOW CHANNEL.  THIS CONVECTION IS
NEARING -60C...WITHIN A MODERATELY SATURATED ENVIRONMENT WITH TPWS
AOA 1.5"... SHOULD BE SUPPORTIVE OF CONVECTIVE RATES OF 1.5"/HR OR
GREATER...WITH THE POTENTIAL OF PRODUCING 1-1.5" TOTALS AS IT
TRACKS THROUGH AREAS FROM BWD TO FTW THAT HAVE ALREADY SEEN 1-3". 

DUE TO THE EARLIER RAINFALL...FFG VALUES HAVE DROPPED BELOW 1"
FROM RUNNELS/COLEMAN COUNTIES TO LOVE/MARSHALL COUNTIES NORTH OF
THE RED RIVER IN OK.   WITH THESE CONVECTIVE RATES THERE IS A
MODERATE POTENTIAL TO EXCEED THESE LOWER FFG FOR ISOLATED FLASH
FLOODING CONDITIONS OVER THE NEXT 1-3 HOURS.  HOWEVER...PROLONGED
MODERATE RAINFALL WITH RATES OF .5-1.0"/HR AFTER WEAK INSTABILITY
IS EXHAUSTED WILL LIKELY LEAD TO LONGER DURATION INUNDATION
FLOODING WITH THE LIKELIHOOD OF REPEAT REDEVELOPMENT AND
TRAINING...PARTICULARLY ACROSS THE DFW METRO AREA INTO THE EARLY
MORNING HOURS...THIS IS GENERALLY SUPPORTED BY MANY HI-RES CAMS
PARTICULARLY THE ARW (THOUGH THE AXIS MAY BE A COUNTY OR TWO TOO
FAR NORTH). 

GALLINA

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

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

LAT...LON   34079680 33909548 33069519 32169630 31639849 
            31549920 31829970 32479925 33149815