Quantitative Precipitation Forecast
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FOUS30 KWBC 181309
QPFERD

EXCESSIVE RAINFALL DISCUSSION
NWS WEATHER PREDICTION CENTER COLLEGE PARK MD
908 AM EDT FRI JUL 18 2014

...VALID 15Z FRI JUL 18 2014 - 12Z SAT JUL 19 2014...
...REFERENCE AWIPS GRAPHIC UNDER...DAY 1 EXCESSIVE RAINFALL...


SLIGHT RISK OF RAINFALL EXCEEDING FFG TO THE RIGHT OF A LINE FROM
15 SE KCRH 25 ESE KGVX 10 SE KBQX KBQX 20 W GLS 25 SSW JAS
15 N POE 10 N AEX 10 N ESF 30 E HEZ 25 W PIB 30 NNW MOB 15 N MOB
PQL 20 S HSA 30 SSE 7R3 30 SSE P92 15 SE SRN 40 NE KEHC
15 SE KCRH.

MODERATE RISK OF RAINFALL EXCEEDING FFG TO THE RIGHT OF A LINE FROM
15 SSW P92 20 SSW KVNP 25 SE KCMB 25 NW KCRH 20 W KVBS 10 E BPT
20 NW CWF 10 SSW ACP 35 E ACP 35 WNW BTR 10 WNW BTR BTR
20 SE BTR 30 NNE 7R3 15 NE 7R3 15 SSW P92.


15Z UPDATE...
TRIMMED WRN PORTION OF PREVIOUS OUTLOOK AREA WHERE FF THREAT HAS
DIMINISHED.  ALSO EXTENDED SLIGHT RISK AREA SLIGHTLY EWD IN
ANTICIPATION OF CURRENT STG CONVECTION OVER SRN LA CONTINUING TO
WORK SLOWLY EWD TODAY ALONG AXIS OF VERY HI PWS AND MODEST
INSTABILITY...WITH HEAVIER RAINS FOCUSING ALONG AND JUST NORTH OF
WEAK WARM FRONTAL BNDRY EXTENDING EWD FROM NEAR MSY TO NEAR MOB.
ALREADY HAVE SEEN RAINFALL RATES IN EXCESS OF 3 INCHES IN AN HOUR
ACRS PARTS OF THE UPR TX COAST INTO SRN LA IN THE LAST HOUR OR TWO
AND WILL LIKELY CONTINUE TO SEE POTNL RAINFALL AMOUNTS OF 3 TO 5
INCHES IN SOME OF THE STGR/SLOW MOVING CONVECTIVE
BANDS..ESPECIALLY OVER SRN LA GIVEN SFC DPS IN THE UPR 70S AND PWS
OVER 2.25 INCHES.  SULLIVAN   PREVIOUS DISCUSSION FOLLOWS...


THE SIGNIFICANT TO EXCESSIVE RAINFALL EVENT WILL CONTINUE THIS
PERIOD..AND ESPECIALLY OVER THE LOWER MS VALLEY.  WHILE THE
NORTHERN PORTION OF THE H5 TROF OVER THE SOUTHERN PLAINS IS
EXPECTED TO LIFT MORE RAPIDLY NORTHEASTWARD INTO THE OH VALLEY BY
THE END OF THE PERIOD..TAKING MODEST LOW LEVEL WARM AIR ADVECTION
AND INCREASING RAINS WITH IT THRU THE TN AND UPPER OH VALLEYS
LATER FRIDAY AFTERNOON AND NIGHT..THE WEAKER SOUTHERN PORTION OF
THE TROF WILL BE SLOWER MOVING WITH EVEN SOME HEIGHT RISES
OCCURRING OVER THE LOWER MS VALLEY/CENTRAL GULF COAST STATES LATER
IN THE PERIOD.  AS A RESULT OF THIS WEAKENING AND SLOWER MOVING
SOUTHERN PORTION OF THE H5 TROF..THE VERY HIGH PWS IN THE 2 TO
2.25+ INCH RANGE WILL REMAIN IN PLACE FROM THE TX COAST AROUND TO
THE FL PANHANDLE.  THIS VERY HIGH MOISTURE AVAILABILITY..ALONG
WITH BROAD WARM AIR ADVECTION LIFT..WILL CONTINUE TO FUEL SOME
STRONG AND ORGANIZED TSTM CLUSTERS/CONVECTION..WITH VERY HEAVY
RAINFALL RATES EXPECTED.  THE MODEL QPFS ARE IN A LITTLE BETTER
AGREEMENT TONIGHT..AT LEAST IN TERMS OF WHERE THE MORE OVERALL
SIGNIFICANT RAINS WILL OCCUR..BUT THERE CONTINUES TO BE A TENDENCY
BY THE GLOBAL MODELS TO EMPHASIS THE HEAVIEST RAINS UP IN THE TN
VALLEY..WHILE THE HIRES MODELS KEEP THE HEAVIEST RAINS DOWN OVER
THE LOWER MS VALLEY/CENTRAL GULF COAST AREA.  ALTHOUGH NOT
PERFECT..THE HIRES MODELS HAVE BEEN DOING A BETTER JOB TO THIS
POINT..AND PREFER THE HIRES IDEA OF THE HEAVIEST RAINS FARTHER
SOUTH VICINITY OF THE DEEPER MOISTURE AND FOCUSING SURFACE
FRONT..WITH THE ASSUMPTION THAT THE EXPECTED CONVECTIVE
DEVELOPMENT FARTHER SOUTH WILL ROB SOME OF THE MOISTURE INFLOW
FARTHER NORTH.   IN THIS HEAVIEST RAINFALL AXIS THRU THE LOWER MS
VALLEY/CENTRAL GULF COAST REGION..EXPECT SOME LOCAL 1-2 INCH
RAINFALL AMOUNTS IN AN HOUR OF SO AND MORE WIDESPREAD AREAL
AVERAGE TOTALS OF 2-4 INCHES THIS ENTIRE PERIOD..WITH ISOLATED
HEAVIER AMOUNTS QUITE POSSIBLE.

TERRY





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