Quantitative Precipitation Forecast
Issued by NWS

Current Version | Previous Version | Graphics & Text | Print | Product List | Glossary On
Versions: 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28
000
FOUS30 KWBC 220755
QPFERD

EXCESSIVE RAINFALL DISCUSSION
NWS WEATHER PREDICTION CENTER COLLEGE PARK MD
355 AM EDT SAT JUL 22 2017

...VALID 12Z SAT JUL 22 2017 - 12Z SUN JUL 23 2017...
...REFERENCE AWIPS GRAPHIC UNDER...DAY 1 EXCESSIVE RAINFALL...


MARGINAL RISK OF RAINFALL EXCEEDING FFG TO THE RIGHT OF A LINE FROM
40 SW OLS 40 WSW OLS 30 S CGZ GEU 25 WSW PRC 30 NE IGM SGU
15 NW CDC 25 ESE MLF 50 ENE MLF 50 WNW 4HV 35 WNW 4HV 35 WSW 4HV
40 E BCE 35 ESE BCE 20 NW PGA 15 SSE PGA 50 SE PGA 70 SE PGA
50 NE INW 40 NNE RQE MTJ 10 SSW BJC 15 E IML 30 SSW LXN
30 WSW HJH 15 WSW FNB 30 NW CDJ UIN 15 ESE IKK 15 WNW HAI FPK
10 NNW MOP 30 SSW LDM ETB 25 NNE DLL 10 WSW CWA 20 NNE RPD
20 SW MZH 20 SE FOZ 15 ESE BDE 10 ENE RRT 25 S CXEA 30 NW CWXZ
40 NNE DRM 20 WNW CYZE 15 ENE CWNL 35 WSW CWWX 40 SW CYVV
15 S CWLS 20 WSW CXDI 10 NNW GKJ 25 NW IPT 10 WSW AVP 25 S FOK
85 ESE MJX 50 ESE ACY 35 SE ACY 25 SSE WWD 10 S CGE 10 NNW CHO
15 NW MTV 20 WSW MRN CEU 25 NE GVL 35 WNW RHP 20 NNE TYS
20 SE LOZ 25 SSE LEX 25 ENE HNB 20 SE MVN 35 NW FAM 25 NNE CNU
25 NNW HUT 45 NNE GCK 50 NW GCK 45 E LAA 20 NW EHA DHT
55 ENE 4CR 15 WNW ROW 25 SW ATS 20 SE GDP 30 NNW E38 15 SSE E38
105 S MRF 130 ESE MMCU.

SLIGHT RISK OF RAINFALL EXCEEDING FFG TO THE RIGHT OF A LINE FROM
55 S OLS 20 WNW FHU 60 E IWA 45 W SOW 25 NW SOW 25 N SOW SJN
15 WSW GNT 20 SW 4SL 4SL 20 NNW 4SL 50 SSE DRO 20 E DRO
25 WNW CPW 30 S GUC 15 ESE GUC 25 NNE MYP 40 W AFF 20 W AFF
15 NE COS 30 ESE COS 20 WNW LHX 35 S LHX 40 NW CAO 50 WSW CAO
30 ENE LVS LVS 15 E CQC 25 NNW 4CR 10 W 4CR SRR 35 ENE ALM
45 WNW GDP 40 SE MMCS 55 SSE MMCS 80 S MMCS.

SLIGHT RISK OF RAINFALL EXCEEDING FFG TO THE RIGHT OF A LINE FROM
15 SSE HTS 40 SE ILN 35 W HAO 15 SE AID 20 N GUS 20 SE TDZ
15 SE YNG 20 SW UNV 10 NE MUI 15 E RDG TTN 10 SE BLM 20 S MJX
10 SSE ACY 15 ESE DOV 10 E FDK 25 SSE CBE W99 20 W LWB 35 NW I16
15 SSE HTS.


...MID ATLC WWD THROUGH THE OH AND MID MS VALLEYS AND CNTL
PLAINS...

  ...SLIGHT RISK OF EXCESSIVE RAINS OR PARTS OF THE OH VALLEY EWD
INTO THE NRN MID ATLC...

NUMEROUS SHOWERS AND TSTMS ARE EXPECTED TO SPREAD EWD FROM ONGOING
EARLY MORNING CONVECTION/MCS ACROSS PARTS OF THE MIDWEST/OH VALLEY
ASSOCD WITH A WEAK AREA OF LOW PRES AND CONVECTIVELY ENHANCED
S/WV...STRADDLING AN E/W FRONTAL BNDRY.  VERY DEEP MSTR WITH PWS
AOA 2 INCHES ARE EXPECTED TO POOL ALONG THE BNDRY..MAXIMIZING ACRS
PARTS OF THE MID ATLC EAST OF THE APLCNS SAT AFTN.   MODELS
SUGGEST A RE-INTENSIFICATION OF REMNANT MCS ACTIVITY AS IT MOVES
INTO PA/WV AND POINTS EAST BY AFTN AS DAYTIME HEATING AWAY FROM
DENSER OVERCAST ALLOWS FOR STG DESTABILIZATION OF THE AIRMASS.
MODEL PREFERENCE WISE...GLOBAL MODEL RUNS WERE CERTAINLY TOO FAR
NORTH WITH HEAVIER CONVECTIVE RAINS ACRS THE MIDWEST ON FRI/FRI
NIGHT AND THAT MAY BE AGAIN THE CASE TODAY.  HI RES GUIDANCE
ESPECIALLY THE EXPERIMENTAL HRRR HAS AT LEAST CAPTURED THE
EVOLUTION OF MCS ACTIVITY ACRS THE MIDWEST REASONABLY WELL AND
THAT TOGETHER WITH THE NAM CONEST AND EVEN THE WRF ARW APPEAR TO
BE A GOOD BLEND FOR DOWNSTREAM DVLPMENT TODAY.  THAT WOULD SUGGEST
HEAVIEST RAIN AXIS WITH AREAL AVG AMOUNTS IN EXCESS OF AN INCH
ACRS PARTS OF SE OH INTO MUCH OF SRN PA..SRN NJ INTO NRN MD AND
NRN WV...WITH DEEPER LAYERED WLY FLOW SUGGESTING DECENT CHANGE OF
TRAINING AND BOWING LINE SEGMENTS PSBLY LEADING TO FLASH FLOODING.
GIVEN THE VERY HIGH PWS..LOCAL RAINFALL RATES EXCEEDING 2 INCHES
PER HOUR WILL BE PSBL.   BEHIND THE MAIN WAVE...DEEP MSTR WILL
REMAIN POOLED ALONG THE BNDRY EXTENDING WWD THRU THE MIDWEST/MID
MS VALLEY AND CNTL PLAINS WITH VERY UNSTABLE CONDS EXPECTED WHICH
SHOULD LEAD TO SCTD CONVECTION ALONG THE BNDRY INTO SAT NIGHT.
SOME EMBDD SMALLER SCALE MCS ACTIVITY WILL BE PSBL WHICH COULD
LEAD TO ISOLD HEAVIER CONVECTIVE RAINS ALONG THE BNDRY FROM THE
CNTL PLAINS INTO THE MID MS VALLEY AIDED BY WEAK S/WV ENERGY
EJECTING OUT OF THE CNTL ROCKIES.  HOWEVER CONFIDENCE IN QPF
DETAILS HERE ARE LOWER AND THUS HAVE TAKEN MORE OF AN ENSEMBLE
APCH TO QPF ACROSS THIS AREA.

...UPPER MS VALLEY/WRN GT LAKES

HEIGHT FALLS IN ADVANCE OF UPPER LOW DROPPING ESEWD FROM MANITOBA
WILL HELP TRIGGER SCTD CONVECTION AHEAD OF ASSOCD LOW PRES AND
COLD FRONT MOVING ACRS THE UPPER MS VALLEY ON SAT.  AIRMASS AHEAD
OF THE FRONT REMAINS MODERATELY MOIST WITH SFC DPS IN THE UPPER
60S AND WITH MODELS SHOWING SOME FAIRLY DECENT INSTABILITIES DVLPG
DURING THE DAY.  WHILE THE MORE ORGANIZED HEAVIER RAINS WILL
LIKELY DVLP NORTH OF THE BORDER IN THE EVOLVING COMMA HEAD...SOME
STGR CELLS OR LINE SEGMENTS COULD PRODUCE SOME LOCALIZED HEAVIER
RAINS FROM ERN MN INTO WI/U.P. OF MI SO COULD NOT RULE OUT AN
ISOLD RISK OF FLASH FLOODING. HAVE INCLUDED THIS REGION IN A
MARGINAL RISK FOR THIS REASON.

...SOUTHWEST/GREAT BASIN/CENTRAL ROCKIES...

  ...SLIGHT RISK OF EXCESSIVE RAINS FROM SE AZ/SW NM NEWD INTO SRN
CO...

WHILE SLIGHT UPPER RIDGING IS FCST ACRS THE GT BASIN THIS PD
OVERALL 5H PATRN REMAINS VERY WEAK WITH LITTLE STEERING FLOW.
ACRS THE 4 CORNERS REGION...LITTLE CHANGE IS EXPECTED TO THE
OVERALL MSTR PROFILES WITH PERHAPS SOME SLIGHT INCREASE IN OVERALL
PWS ACRS SRN PORTIONS OF AZ DURING THE PD.  SCTD DIURNALLY
ENHANCED CONVECTION WILL ONCE AGAIN BE THE RULE ACRS THIS REGION.
WEAK UPPER SHEAR AXIS NOTED ACRS WRN CO MAY LEAD TO SOME SLIGHTLY
HEAVIER ORGANIZED RAIN AMOUNTS ACRS PARTS OF SRN CO INTO NRN
NM..WHILE HAVE INDICATED SOMEWHAT HEAVIER QPF TOTALS ACRS SERN
AZ/SW NM IN AREA OF WEAK 85H-7H CONFLUENCE.  PATRN WILL AGAIN
SUPPORT THE POTNL FOR FLASH FLOODING ACRS PARTS OF THE
REGION..ESPECIALLY ACROSS BURN SCAR AREAS AND NEAR STEEPER TERRAIN
WITH GREATEST RISK OF FLASH FLOODING FROM SE AZ/SW NM NEWD INTO
SRN CO WHERE A SLIGHT RISK OF EXCESSIVE RAINS HAS BEEN PLACED.


SULLIVAN
$$





USA.gov is the U.S. government's official web portal to all federal, state and local government web resources and services.