Flash Flood Guidance
Issued by NWS

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159
AWUS01 KWNH 231254
FFGMPD
PAZ000-MDZ000-VAZ000-WVZ000-OHZ000-KYZ000-INZ000-231553-

MESOSCALE PRECIPITATION DISCUSSION 0542
NWS WEATHER PREDICTION CENTER COLLEGE PARK MD
854 AM EDT SUN JUL 23 2017

AREAS AFFECTED...EASTERN IN, CENTRAL OH & NORTHERN WV

CONCERNING...HEAVY RAINFALL...FLASH FLOODING POSSIBLE

VALID 231253Z - 231553Z

SUMMARY...ELEVATED CONVECTION IS SHOWING AN UPTICK OVER SATURATED
SOILS.  HOURLY RAIN RATES TO 2" WITH LOCAL AMOUNTS OF 3" ARE
POSSIBLE UNTIL CIN ERODES.

DISCUSSION...THUNDERSTORMS ARE STARTING TO FORM ALONG AN AXIS
STRETCHING FROM EASTERN IN ACROSS OH INTO NORTHERN WV NEAR A
BOUNDARY AT 850 HPA WELL NORTH OF AN OUTFLOW BOUNDARY.  OTHER
ACTIVITY IS FORWARD PROPAGATING FROM THE SOUTHWEST ACROSS SOUTHERN
IN.  THE REGION IS WITHIN A GRADIENT IN THE MU CAPE FIELD, WITH
VALUES NEAR 1000 J/KG.  ALOFT, THE AREA IS DIVERGENT TO THE
SOUTHEAST OF AN UPPER LEVEL LOW NEAR THE UPPER PENINSULA OF MI,
WITH A JET STREAK NOTED NORTH OF LAKE ERIE.  SOUNDINGS IN THE AREA
SHOW SATURATION IN THE LOW-LEVELS.  INFLOW AT 850 HPA IS 20-30 KTS
PER VAD WIND PROFILES FROM THE INSTABILITY POOL TO ITS WEST.
EFFECTIVE BULK SHEAR OF 25-30 KTS EXISTS HERE.  PRECIPITABLE WATER
VALUES ARE 1.75-2" PER GPS DATA.

FLASH FLOOD GUIDANCE VALUES ARE LOW FROM RECENT HEAVY RAINFALL,
WHICH INCREASES THE IMPACT THUNDERSTORMS WITH RAIN RATES OF ANY
SIGNIFICANT MAGNITUDE.  THE AVAILABLE MOISTURE AND INSTABILITY
SUPPORT HOURLY RAIN RATES UP TO 2" WITH LOCAL AMOUNTS TO 3",
VALUES RECENT HRRR RUNS ARE TRENDING TOWARDS ACROSS EASTERN IN AND
WESTERN OH.  BELIEVE ISSUES SHOULD LAST A FEW HOURS UNTIL CIN
ERODES DUE TO DAYTIME HEATING, REDUCING THE THREAT FOR ELEVATED
CONVECTION.

ROTH

...PLEASE SEE WWW.WPC.NCEP.NOAA.GOV FOR GRAPHIC PRODUCT...

ATTN...WFO...CLE...CTP...ILN...IND...IWX...LWX...PBZ...RLX...
RNK...

ATTN...RFC...MARFC...OHRFC...

LAT...LON   40838481 40658270 40008135 39917889 39117882
            38677931 38198026 39108320 39228427 38978509
            39108605 40098630 40438617



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