Quantitative Precipitation Forecast
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000
FOUS30 KWBC 201504
QPFERD

EXCESSIVE RAINFALL DISCUSSION
NWS WEATHER PREDICTION CENTER COLLEGE PARK MD
1103 AM EDT THU JUL 20 2017

...VALID 15Z THU JUL 20 2017 - 12Z FRI JUL 21 2017...
...REFERENCE AWIPS GRAPHIC UNDER...DAY 1 EXCESSIVE RAINFALL...


MARGINAL RISK OF RAINFALL EXCEEDING FFG TO THE RIGHT OF A LINE FROM
95 S GBN 85 S GBN 25 E GBN 30 NW LUF 35 ESE IGM 50 NNE IGM
45 ENE LSV 10 ESE HND 30 SW HND 55 NE DRA 55 ESE ELY 10 SSW SLC
25 W BPI 20 SE BVR 15 SSE FNL 30 ESE LXV 15 NE MYP 15 E CPW
25 E DRO DRO FMN 35 SSE FMN GNT 55 SSW ABQ 30 WSW 4CR 15 SSE SRR
50 SSE ALM ELP 80 S MMCS 95 S MMCS.

MARGINAL RISK OF RAINFALL EXCEEDING FFG TO THE RIGHT OF A LINE FROM
CKN 15 WSW MOX MKT 15 SSE FKA MRJ 20 ESE BEH 15 NNW LPR CWWB
25 NNW ROC 40 SE UCA 30 N POU 20 ENE MPO 30 ESE BFD 20 SW CBE
20 SE 48I 20 WNW UNI 20 WNW EYE 10 SE GBG TNU 15 SW SUX
20 WNW ONL 45 E IEN 25 N BFF 40 NE SIB 20 NE BFU 60 NNE GCC
55 W 2WX 25 SW 2WX 35 NNE RCA 25 NW PHP 20 NE PIR 50 NW ABR
25 SW K46D 30 E N60 20 NE K08D 30 ESE CYEN 20 NNW CWEI CXDW
15 N HCO CKN.

MARGINAL RISK OF RAINFALL EXCEEDING FFG TO THE RIGHT OF A LINE FROM
45 SE APF 25 E SRQ 10 NNW BKV 20 SE CTY 30 NW GNV 25 SW SGJ
20 SSE DAB 10 N SUA FXE 25 W HST 45 SE APF.

SLIGHT RISK OF RAINFALL EXCEEDING FFG TO THE RIGHT OF A LINE FROM
75 SW OLS 80 WNW OLS 25 SSW CGZ 15 E FFZ 35 NNE DVT 30 NNE PRC
10 NE 40G 35 NNE FLG 10 N INW 35 N SOW 10 ENE SJN 65 NW TCS
40 SSE DMN 100 SW MMCS.

SLIGHT RISK OF RAINFALL EXCEEDING FFG TO THE RIGHT OF A LINE FROM
35 NE U24 15 ESE PVU 50 ENE PVU 35 SSE FIR 25 ESE FIR
30 SSW CMS 30 N VEL 10 ENE VEL 15 SE VEL 20 SSE PUC 25 NW 4HV
30 SW 4HV 30 SE BCE 40 E SGU 20 ENE SGU 35 NW CDC 35 NE U24.

SLIGHT RISK OF RAINFALL EXCEEDING FFG TO THE RIGHT OF A LINE FROM
9V9 15 WNW PQN 15 WSW AEL 10 S CCY 20 E EBS 10 SE YKN
40 NNW ONL 10 SE ICR 9V9.


NO SIGNIFICANT CHANGES WERE MADE TO THE DAY 1 EXCESSIVE RAINFALL
OUTLOOK...JUST MINOR ADJUSTMENTS BASED UPON CURRENT
SATELLITE/RADAR TRENDS.

PEREIRA

...SOUTHWEST INTO THE CNTL ROCKIES...

LITTLE CHANGE IN THE OVERALL PATRN ACROSS THE SW U.S. AS MONSOONAL
CIRCULATION CONTINUES AROUND THE RATHER LARGE UPPER RIDGE OVER THE
CNTL PLAINS/MID MS VALLEY.  MULTIPLE DAYS OF RAIN ACRS THIS REGION
HAVE ELEVATED THE FLASH FLOOD RISK..WHILE MSTR REMAINS FAIRLY WELL
ENTRENCHED FROM AZ/WRN NM...WITHE MDTLY HI PWS EXTENDING NWD
THROUGH PARTS OF UT/WRN CO. A WEAK UPPER SHEAR AXIS EXTENDING NEWD
FROM A WEAK VORT DRIFTING NWWD INTO SRN NV WILL HELP SUPPORT A BIT
MORE UNIDIRECTIONAL S TO SWLY FLOW TO ITS EAST ACRS UT.  THAT
TOGETHER WITH FCST CAPE VALUES OF 500 TO 1000 J/KG AND PWS IN
EXCESS OF .75 INCHES COULD LEAD TO SOME MDTLY HEAVY CNVTV CELLS
THAT COULD REPEAT WITH OVERALL CELL MOTION EXPECTED TO BE MDTLY
SLOW.  FOR THIS REASON...HAVE PLACED A SLIGHT RISK WITHIN A MUCH
BROADER MARGINAL RISK AREA THROUGH MUCH OF THE WASATCH RANGE AREA
WHERE HEAVIER RAIN RATES ACRS THE STEEPER TERRAIN WILL ENHANCE
RUNOFF ISSUES.  FARTHER SOUTH..HAVE MAINTAINED A SLIGHT RISK FOR
MUCH OF CNTL/SE AZ WHERE MODEL SUPPORT IN THE HIGH RES GUIDANCE
ONCE AGAIN SUPPORTS SCTD RAIN TOTALS IN EXCESS OF 1 TO 1.5 INCHES
IN AN HOUR OR TWO PARTICULARLY DURING THE LATE AFTN AND EVENING
HOURS DURING PEAK HEATING.  WEAK VORT NOTED NEAR THE TX/SRN NM
BORDER IS FCST TO LIFT NNWD ALONG TOWARD THE ERN AZ BORDER WHICH
MAY PROVIDE A LOCAL FOCUS FOR HEAVIER RAIN ALONG THE STATE BORDERS
DURING THE AFTN/EVENING.

...NRN PLAINS EWD INTO THE MIDWEST/OH VALLEY..PA/NY...

FAIRLY ACTIVE WEATHER PATRN WILL REMAIN TO THE NORTH OF A FAIRLY
STG UPPER RIDGE OVER THE CNTL PLAINS/MID MS VALLEY REGION AS A
WEAK COLD FRONT SETTLES SWD ALONG THE SRN EDGE OF THE WLYS.
MODELS HAVE STRUGGLED WITH EARLY MCS THAT AFFECTED PARTS OF THE
MIDWEST WED NIGHT AND SUSPECT MODELS WILL ONCE AGAIN STRUGGLE WITH
CONVECTIVE DVLPMENT/TIMING DURING THE DAY 1 PD TODAY ALONG THE
BNDRY FROM PARTS OF NEB/SD EWD THROUGH THE OH VALLEY INTO PARTS OF
THE NRN MID ATLC/NE.  EARLY IN THE PD...REMNANT MCS TIED MORE TO
WEAK SYNOPTIC WAVE WILL LIKELY SUPPORT AN AREA OF MDT CONVECTIVE
RAINS THROUGH PARTS OF LOWER MI INTO WRN NY WHILE AT THE SAME TIME
A WEAKENING AREA OF TSTMS WILL LIKELY DROP SEWD THROUGH PARTS OF
IL/IN AND WRN OH.  BY LATE THUR/THUR EVENING...MODELS SHOW SOME
VERY IMPRESSIVE POOLING OF PWS AOA 2 INCHES ALONG THE FRONT FROM
THE MIDWEST INTO THE OH VALLEY WITH MLCAPES IN EXCESS OF 4 THSD
J/KG.  DESPITE LITTLE IN THE WAY OF MID/UPR FORCING AT THAT
TIME...THE THERMO/MSTR PROFILES WOULD SUGGEST ANY CONVECTION THAT
DVLPS COULD HAVE THE POTNL TO RAPIDLY INTENSIFY WITH IMPRESSIVE
RAIN RATES THAT COULD LEAD TO RUNOFF ISSUES ACRS THE AREA.   HAVE
LEANED A BIT CLOSER TO SOME OF THE WETTER SOLNS INCLUDING THE NAM
CONUS NEST GIVEN THE ABOVE.   ADDITIONAL S/WV ENERGY AND REMNANT
MCVS WORKING EWD FROM THE CNTL HI PLAINS WILL LIKELY LEAD TO
ADDITIONAL ORGANIZED TSTMS FROM PARTS OF NEB/SD EWD INTO IA/SRN MN
THUR NIGHT PRIMARILY ALONG AND NORTH OF THE STATIONARY FRONT WITH
SOMEWHAT LOWER CONFIDENCE IN QPF DETAILS GIVEN MODEST MODEL QPF
SPREAD HERE.  LIKEWISE PATRN HAS THE POTNL TO SUPPORT LOCALIZED
HEAVY RAIN/POTNL MCS DVLPMENT THAT COULD LEAD TO FLASH FLOODING IN
SPOTS. FOR HIGHLIGHTED MOST OF THE REGION FROM THE NRN PLAINS INTO
THE OH VALLEY/NY/PA IN A MARGINAL RISK GIVEN RATHER LARGE MODEL
SPREAD..WHILE INDICATING A SLIGHT RISK FOR PORTIONS OF SE SD INTO
NRN IA WHERE SLIGHTLY HIER MODEL AGREEMENT EXISTS THURSDAY NIGHT
FOR POTNL ORGANIZED CONVECTION ALONG THE FRONT UNDER STRENGTHENING
WAA PATRN AHEAD OF AN EXPECTED WEAK SFC LOW FORMING ALONG THE
FRONT OVER THE CNTL PLAINS.

...FL...

SOME RISK OF ISOLD FLOODING IS INDICATED FROM THE FLORIDA
PENINSULA WITH ACTIVE SEA BREEZES AND HI PWS IN EXCESS OF 2 INCHES
SUPPORTING THE POTNL FOR VERY HEAVY DOWNPOURS ESPECIALLY OVER
INTERIOR PORTIONS WITH CONVERGENT SEA BREEZES DURING THE LATE
AFTN/EVENING THAT COULD SUPPORT SOME HOUR RAIN RATES IN EXCESS OF
2 INCHES.


SULLIVAN
$$





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