Quantitative Precipitation Forecast
Issued by NWS

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FOUS30 KWBC 251339
QPFERD

EXCESSIVE RAINFALL DISCUSSION
NWS WEATHER PREDICTION CENTER COLLEGE PARK MD
939 AM EDT SAT MAR 25 2017

...VALID 15Z SAT MAR 25 2017 - 12Z SUN MAR 26 2017...
...REFERENCE AWIPS GRAPHIC UNDER...DAY 1 EXCESSIVE RAINFALL...


MARGINAL RISK OF RAINFALL EXCEEDING FFG TO THE RIGHT OF A LINE FROM
15 SE KMDJ 15 ENE S58 30 NNE KSPR 15 SSE P92 20 N 7R3 MCB
25 NE JAN 45 W TUP 30 SSE OLV 15 WNW MKL 25 SSE PAH 25 W HOP
20 SW CKV 50 SW BNA 30 NNW MDQ 35 NW CHA 25 NNE DNN 30 E DNN VPC
25 NW LGC 20 WSW AUO HRT 40 ENE KVOA.


15Z UPDATE...

ACRS THE CNTL GULF COAST AND TN VALLEY..NO CHANGES WERE MADE TO
MARGINAL RISK AREA.   WHILE SOME WEAKENING OF CONVECTION ALONG
PREFRONTAL SQLN IS ANTICIPATED THIS MRNG.. ADDITIONAL STORMS ARE
EXPECTED TO FLARE UP BY AFTERNOON WITH SFC HEATING ALONG LEADING
OUTFLOW BNDRY AND PROBABLY TO A LESSER DEGREE ALONG TRAILING COLD
FRONT.  ACTIVITY SHOULD REMAIN FAIRLY PROGRESSIVE AS UPR TROF
MAINTAINS A SLIGHT NEG TILT ACRS THE TN/LOWER MS VALLEY..AND
OVERALL SHOULD SEE A TREND TOWARD LOWER AMOUNTS AS WE HEAD TOWARD
THE OVERNIGHT PD AS UPR TROF BEGINS TO LIFT MORE NEWD TOWARD THE
OH VALLEY WHICH WILL CONTINUE TO WEAKEN THE LOW LEVEL INFLOW ACRS
THE GULF COAST REGION.  HI RES RUNS HAVE GENLY HAD A DECENT HANDLE
ON CONVECTIVE TRENDS WITH MINOR TIMING ISSUES AND SUGGEST AREAL
AVG AMOUNTS OF .50 TO 1 INCH CAN BE EXPECTED AS ACTIVITY ADVANCES
EWD TODAY WITH PERHAPS SOME ISOLD AMOUNTS OF 2+" IN SOME OF THE
SLOWER MORE ORGANIZED CONVECTIVE BANDS.  THESE HEAVIER AMOUNTS
COULD RESULT IN ISOLD RUNOFF ISSUES IN AREAS OF SLOW/POOR
DRAINAGE..OTHERWISE FOR MOST OF THE REGION THE EXPECTED RAINS ARE
NOT EXPECTED TO RESULT IN ORGANIZED RUNOFF ISSUES ESPECIALY OVER
THE SRN PORTION OF THE MARGINAL RISK AREA WHERE FFG VALUES ARE
QUITE HI.  SULLIVAN  PREVIOUS DISCUSSION FOLLOWS...

...CENTRAL GULF COAST STATES AND TN VALLEY...

GUIDANCE STILL REASONABLY AGREES THAT AN AMPLIFIED MID-UPPER LEVEL
TROUGH/CLOSED LOW WILL STEADILY PROGRESS ACROSS THE MID-MS VALLEY
STATES DAY1 WHILE TAKING ON MORE NEGATIVE TILT. ACTIVE BANDED
CONVECTION SHOULD STILL FLOURISH DAY1 AS HEIGHT FALLS AIDED BY TX
SHORTWAVE APPROACH...INSTABILITY...AND GULF OF MEXICO AND
MID-LEVEL ERN PACIFIC MOISTURE ADVECTION AS PER AN ENHANCED LLJ
FUELS DEVELOPMENT OF STRONG TO SEVERE CONVECTION AS PER SPC. THIS
OCCURS AHEAD OF A TRAILING COLD FRONT/CONVECTIVE COLD POOL PUSHING
ACROSS THE REGION. SUSPECT THAT HEAVIEST RAINFALL WITH SOME
TRAINING/RUNOFF POTENTIAL IS EXPECTED TO FLOURISH IN AN AREA OF
DEEPER MOISTURE AND INSTABILITY OVER THE CENTRAL GULF COAST STATES
INTO THE TN VALLEY AND WITH TERRAIN LIFT INTO THE FAR SRN
APPALACHIANS. SOME LOCALLY HEAVY 2+" AMOUNTS ARE POSSIBLE EVEN
WITH OVERALL SYSTEM PROGRESSION ALONG WITH SOME THREAT FOR RUNOFF
ISSUES. OVERALL WPC DAY 1 QPF LEANED HEAVILY ON WPC CONTINUITY
BLENDED WITH ARW/SSEO MEAN GUIDANCE FOR UPDATED DETAILS.

SCHICHTEL
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