Quantitative Precipitation Forecast
Issued by NWS

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FOUS30 KWBC 131348
QPFERD

EXCESSIVE RAINFALL DISCUSSION
NWS WEATHER PREDICTION CENTER COLLEGE PARK MD
947 AM EDT SAT SEP 13 2014

...VALID 15Z SAT SEP 13 2014 - 12Z SUN SEP 14 2014...
...REFERENCE AWIPS GRAPHIC UNDER...DAY 1 EXCESSIVE RAINFALL...


SLIGHT RISK OF RAINFALL EXCEEDING FFG TO THE RIGHT OF A LINE FROM
50 W MMNL 20 SW MMNL 25 SE MMNL 15 SW HBV 20 NW BKS ALI
15 N RBO 20 N CRP 10 WNW RKP 10 ESE KRP 25 NNE KMIU 35 E KOPM
65 ESE PIL 70 SE MMMA 75 SSW MMMA 70 NNE MMCV 60 SSE MMMY
15 WSW MMAN 35 E MMMV 50 NE MMMV 50 W MMNL.

MADE NO CHANGE TO THE EARLIER ISSUANCE.  THERE CONTINUES TO BE A
STRONG SIGNAL IN THE LATEST MODEL GUIDANCE FOR HEAVY TO EXCESSIVE
RAINFALL POTENTIAL ACROSS SOUTH TEXAS INTO NORTHEASTERN MEXICO
THIS PERIOD.  STRONG SOUTHEASTERLY LOW LEVEL FLOW IN AN AXIS OF
2.00-2.25"+ PW VALUES ASSOCIATED WITH SHORTWAVE ENERGY MOVING
WESTWARD ON THE SOUTHERN SIDE OF THE GULF COAST UPPER RIDGE FROM
THE WESTERN GULF INTO SOUTH TX/NORTHEAST MEXICO WILL PERSIST
THROUGH THIS PERIOD---ALBEIT WITH A WEAKENING TREND DURING THE
SECOND HALF OF THE PERIOD.  THIS WILL SUPPORT POTENTIAL FOR
ADDITIONAL BANDS OF RAIN TO PUSH WESTWARD OFF THE WESTERN GULF AND
INTO SOUTH TEXAS AND NORTHEAST MEXICO.  INTENSE RAINFALL AMOUNTS
POSSIBLE IN THESE BANDS---CONTINUING THE RISK OF LOCALLY EXCESSIVE
AMOUNTS ACROSS SOUTH TEXAS.  THE HI RES GUIDANCE IS SHOWING
POTENTIAL FOR ISOLATED TOTALS IN EXCESSIVE OF 5" ACROSS SOUTH
TEXAS AND ESPECIALLY TO THE SOUTH OF THE BORDER ACROSS THE MEXICAN
STATES OF NUEVO LEON AND TAMAULIPAS.


SLIGHT RISK OF RAINFALL EXCEEDING FFG TO THE RIGHT OF A LINE FROM
35 SSW OGB 20 NNW JYL 20 SSW AGS 10 SE HQU 25 S GRD 40 ENE GRD
TTA 20 NNW RWI ASJ 10 WSW EDE 25 E OCW 10 ENE EWN NCA 40 W MYR
35 SSW OGB.

MADE NO CHANGE HERE ALSO TO THE PREVIOUS ISSUANCE.  LATER
SATURDAY---THE EMPHASIS FOR HEAVY TO EXCESSIVE RAINFALL AMOUNTS
WILL BE IN THE VICINITY OF THE FRONTAL BOUNDARY EXPECTED TO MOVE
SLOWLY SOUTHEASTWARD THROUGH THE SOUTHEASTERN U.S./SOUTHERN MID
ATLANTIC REGION.  ENHANCED UPPER DIFFLUENCE IN THE RIGHT ENTRANCE
REGION OF THE UPPER JET ACROSS THE NORTHEAST WILL COINCIDE WITH
THE AXIS OF ABOVE AVERAGE PW VALUES IN THE VICINITY OF THIS FRONT
LATE THIS AFTERNOON INTO SATURDAY EVENING---SUPPORTING THE
POTENTIAL FOR ORGANIZED CONVECTION IN THE VICINITY OF THIS
BOUNDARY.  QPF DETAILS VARY WIDELY AMONG THE LATEST MODELS--BUT
THERE IS A SIGNAL FOR HEAVY TO POTENTIALLY EXCESSIVE RAINFALL
AMOUNTS IN THE VICINITY OF THIS FRONT FROM PORTIONS OF CENTRAL TO
NORTHEASTERN SC INTO EASTERN NC WITH ISOLATED SHORT TERM RAINFALL
TOTALS OF 1-2"+ AND ISOLATED TOTALS OF 3-5" POSSIBLE.

TERRY
$$





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