MESOSCALE PRECIPITATION DISCUSSION 0088
NWS WEATHER PREDICTION CENTER COLLEGE PARK MD
930 PM EDT SAT APR 01 2017

AREAS AFFECTED...SWRN TX

CONCERNING...HEAVY RAINFALL...FLASH FLOODING POSSIBLE

VALID 020127Z - 020727Z

SUMMARY...RAPID DEVELOPMENT OF CONVECTION BETWEEN 03-06Z MAY CAUSE
A FEW FLASH FLOODING ISSUES ALONG AND JUST NORTHEAST OF THE RIO
GRANDE INTO THE SRN EDWARDS PLATEAU WITH RAINFALL OF 3-5 INCHES
LOCALLY.

DISCUSSION...AT 01Z...REGIONAL RADAR AND GOES 13 INFRARED IMAGERY
SHOWED A COUPLE AREAS OF CONVECTION NEAR THE SERRANIAS DEL BURRO
IN NRN MEXICO MOVING TOWARD THE NORTHEAST AT ROUGHLY 20 KTS...BUT
STRUGGLING AS THEY CROSS THE RIO GRANDE PERHAPS DUE TO INCREASED
CAPPING GIVEN THE ONSET OF NOCTURNAL SURFACE COOLING.
HOWEVER...OVER THE PAST HOUR OR TWO...THE KDFX 850 MB VAD WIND
PLOT HAS SHOWN A STEADY INCREASE IN WIND SPEED...CURRENTLY AT 25
KT FROM THE EAST. THE INCREASED ELY TO SELY LOW LEVEL FLOW AGREES
WITH THE WELL ADVERTISED INCREASE FORECAST BY RECENT RUNS OF THE
RAP/HRRR ALLOWING LOW LEVEL MOISTURE TRANSPORT INTO THE MIDDLE RIO
GRANDE VALLEY.

A VORTICITY MAX NOTED ON WATER VAPOR IMAGERY MOVING EAST ACROSS
THE WRN MEXICAN COAST OF SINALOA...IS FORECAST TO REACH THE BIG
BEND REGION OF TEXAS BY ABOUT 06Z. CYCLONIC VORTICITY ADVECTION
AHEAD OF THIS FEATURE ALONG WITH INCREASING UPPER LEVEL DIFFLUENCE
WITHIN A COUPLED JET SIGNATURE  SHOULD PROVIDE THE NECESSARY LIFT
TO ALLOW RAPID CONVECTIVE EXPANSION IN THE 03-05Z TIME FRAME. AS A
NE-SW ORIENTED COLD FRONT CONTINUES TO ADVANCE SWED ACROSS THE
EDWARDS PLATEAU EARLY TONIGHT...NEWD MOVING CELLS ARE EXPECTED TO
PARALLEL THE BOUNDARY WHILE MOISTURE ADVECTION CONTINUES FROM THE
SE. WHILE PRECIPITABLE WATER VALUES STILL HAVE SOME TIME BEFORE
THEY REACH FORECAST VALUES OF 1.25+ INCHES...TRAINING OF HEAVY
RAIN IS EXPECTED TO LEAD TO LOCALLY HEAVY RAINFALL
TOTALS...POSSIBLY 3-5 INCHES OVER VAL VERDE TO KINNEY COUNTIES
INTO THE UPSLOPE REGION OF THE SRN EDWARDS PLATEAU. THIS SITUATION
WOULD WARRANT A FLASH FLOOD THREAT GIVEN CURRENT FLASH FLOOD
GUIDANCE VALUES OF 2.5 TO 3.5 INCHES IN 3 HOURS.

OTTO

ATTN...WFO...EWX...MAF...

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

LAT...LON   30230049 30039987 29189995 28610074 29190193
            29970180 30200109