MESOSCALE PRECIPITATION DISCUSSION 0231
NWS WEATHER PREDICTION CENTER COLLEGE PARK MD
229 AM EDT WED JUN 17 2015
 
AREAS AFFECTED...CNTRL TEXAS TO THE CNTRL AND UPPER TEXAS COAST 
 
CONCERNING...HEAVY RAINFALL...FLASH FLOODING LIKELY 
 
VALID 170628Z - 171228Z
 
SUMMARY...SIX HOUR RAINFALL TOTALS IN EXCESS OF 7 INCHES ARE
POSSIBLE ACROSS PORTIONS OF CNTRL TEXAS TOWARD THE CNTRL/UPPER
TEXAS COAST THROUGH 12Z. A UNANIMOUS SIGNAL IN THE 00Z HI-RES
MODELS AND RECENT RUNS OF THE HRRR SUPPORT THIS IDEA WITH LIKELY
FLASH FLOODING.

DISCUSSION...AT 06Z...NEWLY DOWNGRADED TROPICAL DEPRESSION BILL
WAS CENTERED NEAR GYB...MOVING DUE NORTH AT AROUND 11 KTS. THREE
HOUR RAINFALL REPORTS AS OF 04Z IN FAYETTE COUNTY SUGGEST KEWX AND
KGRK DUAL POL MAY BE UNDERESTIMATING OBSERVED 1 HR RAINFALL BY UP
TO 1 INCH. THE CENTER OF BILL IS FORECAST TO CONTINUE A NWD MOTION
OVER THE NEXT 6 HOURS WITH RAINFALL RATES OF 1-2 IN/HR JUST NORTH
OF THE CIRCULATION. OF GREATER CONCERN HOWEVER...IS A NEWLY FORMED
FEEDER BAND EXTENDING NNE ACROSS JACKSON...WHARTON AND AUSTIN
COUNTIES...INTO PORTIONS OF BRAZOS COUNTY INCLUDING THE CITIES OF
COLLEGE STATION AND BRYAN. THERE IS A WELL DEFINED LOW LEVEL
CONFLUENCE AXIS IN AREA VWP PLOTS SUPPORTING THE DEVELOPMENT OF
THIS BAND WITH SHORT TERM RAP/HRRR FORECASTING THE CONTINUING OF A
NEARLY STATIONARY FEEDER BAND THROUGH 12Z. 

THERE IS ALSO A NEARLY STATIONARY AXIS OF VERY HEAVY RAINFALL IN
PLACE JUST OFF OF THE CNTRL TEXAS COAST WHICH MAY BE INHIBITING
BETTER MOISTURE/INSTABILITY FROM BEING TAPPED ACROSS INLAND
LOCATIONS. WHILE SATELLITE TRENDS SUGGEST NO APPRECIABLE CHANGE TO
THIS OFFSHORE AXIS OVER THE PAST FEW HOURS...A STRONG CONSENSUS OF
00Z HI-RES MODELS SUPPORTS THE DISRUPTION OF THIS HEAVY RAINFALL
AXIS BETWEEN 09 AND 12Z...WHILE SHIFTING THE HEAVIEST RAINFALL
JUST INLAND TOWARD THE CNTRL TEXAS COAST. THIS MAY ALLOW FOR
EXTREMELY HEAVY RAINFALL WITHIN THE FEEDER BAND LOCATION THROUGH
12Z...WITH TOTALS OF 7-10 INCHES FORECAST BY THE HI-RES MODEL
CONSENSUS.

OTTO

ATTN...WFO...CRP...EWX...FWD...HGX...

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

LAT...LON   32809697 32539611 31909552 31339528 29829530 
            28089595 28309707 30169682 30479741 31049820 
            31699827 32469768