Alert archive / Pennsylvania / Flash Flood Warnings in 2008

Flash Flood Warning 19, NWS Pittsburgh, PA

July 23, 2008Allegheny County, Westmoreland County, Pennsylvania

NWS Pittsburgh, PA issued this flash flood warning at Jul 23, 2008, 1:13 PM EDT for Allegheny County, Westmoreland County, Pennsylvania. It was in force for 3 hr. No storm report in the archive falls inside the area while it was in force.

The area

The counties it named.

The facts

Issued
Jul 23, 2008, 1:13 PM EDT (17:13 UTC)
Expired
Jul 23, 2008, 4:15 PM EDT
In force
3 hr
Issued by
NWS Pittsburgh, PA
Area
Storm-based polygon
Flood severity
None

Counties Allegheny County, PA, Westmoreland County, PA

The radar

The Pittsburgh radar (KPBZ), 45 km from the middle of the area, began a volume at 17:15 UTC, the scan nearest the moment this went out.

Open the radar archive at this moment

The archived warnings, watches and discussions in force at that minute are drawn over the scan, this one among them.

The nearest sounding before it

Washington/Dulle, VA (KIAD), launched 12:00Z, 5.2 hours before the alert went out and 255 km from the middle of its area. This is the routine balloon launch nearest before it, the air the forecaster had in hand, not a measurement taken for the alert.

Skew-T log-pSkew-T log-p diagram, Washington/Dulle, VA at 12:00Z on 2008-07-23Temperature and dew point through the depth of the atmosphere, with the mixed-layer parcel. CAPE 156 joules per kilogram.LCLLFCEL10008507005003002001001 km2 km3 km6 km9 km12 km15 km-30°-20°-10°0°10°20°30°40°
Temperature in red, dew point in green, the mixed-layer parcel dashed.
HodographHodograph, Washington/Dulle, VA at 12:00Z on 2008-07-23The wind through the lowest 10 kilometers. Zero to 1 km storm-relative helicity 13 square meters per square second.193958Sfc1 km3 km6 km9 kmRMLM
The wind turning with height, colored by layer: ground to 1 km, 1 to 3 km, 3 to 6 km, 6 to 10 km.
Mixed-layer CAPE
156 J/kg
Mixed-layer CIN
-226 J/kg
Mixed-layer LCL
992 m above ground
0-6 km bulk shear
40 kt
0-1 km storm-relative helicity
13 m²/s²
0-3 km storm-relative helicity
62 m²/s²
Significant tornado parameter
0.0
Supercell composite
-0.0

Open this sounding in Storm Lab

What forecasters said that day

The local office's own words before this flash flood warning went out, as it sent them, from the Iowa Environmental Mesonet's archive of National Weather Service text.

NWS Pittsburgh, PA wrote its last area forecast discussion before this flash flood warning went out at Jul 23, 10:10 AM EDT, 3 hours 3 minutes earlier.

Area forecast discussion, Jul 23, 10:10 AM EDT, 3 hours 3 minutes before
AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE PITTSBURGH PA
1010 AM EDT WED JUL 23 2008

.SYNOPSIS...
A COLD FRONT WILL CROSS THE REGION TODAY...WITH SHOWERS DIMINISHING.
HIGH PRESSURE WILL BUILD INTO THE REGION THURSDAY...BRINGING DRY AND
SEASONABLY COOL CONDITIONS. THE NEXT FRONTAL SYSTEM WILL IMPACT THE
AREA OVER THE WEEKEND.

&&

.NEAR TERM /THROUGH TONIGHT/...
THE SURFACE COLD FRONT IS CROSSING EASTERN OH/NW PA CURRENTLY...WITH
SHOWERS EXITING THE EASTERN RIDGES...AND THE PARENT UPPER LOW NUDGING
EAST ACROSS THE GREAT LAKES. FOR THIS AFTN...RESIDUAL INSTABILITY TO
THE EAST OF THE COLD FRONT COULD RESULT IN REDEVELOPMENT OF
SHWRS/TSTMS ACROSS THE RIDGES...SO WILL KEEP POPS SCATTERED EAST
OF PITTSBURGH THIS AFTN/EVENING. TO THE NORTH...A WAVE ROTATING
AROUND THE UPPER LOW COULD PROVIDE ENOUGH LIFT/INSTABILITY TO
GENERATE A FEW SHWRS/TSTMS NORTH OF PITTSBURGH THIS AFTN/EARLY
EVENING. FROM PITTSBURGH SOUTH AND WEST...EXPECT LITTLE IF ANY
PRECIP. PRECIP WILL GRADUALLY DIMINISH FOR ALL AREAS TONIGHT.

&&

.SHORT TERM /THURSDAY THROUGH THURSDAY NIGHT/...
HIGH PRESSURE WILL BRING DRY WEATHER FOR THURSDAY INTO THURSDAY
NIGHT WITH NEAR NORMAL TEMPERATURES.

&&

.LONG TERM /FRIDAY THROUGH TUESDAY/...
MEDIUM RANGE MODELS CONTINUE TO BE IN DECENT AGREEMENT BRINGING
THE NEXT FRONTAL BOUNDARY ACROSS THE REGION SATURDAY...WITH
PERHAPS A SECONDARY COLD FRONT FOR SUNDAY. WILL KEEP CHANCE POPS
FOR SAT/SUN. SOME DIFFERENCES FOR EARLY NEXT WEEK...WITH THE GFS
SHOWING YET ANOTHER WAVE CROSSING THE AREA...AND THE ECMWF SHOWING
THE FEATURE DEPARTING TO THE SOUTH. WILL KEEP MINIMAL RESIDUAL
CHANCES FOR MONDAY...WITH DRY CONDITIONS FOR TUESDAY. NEAR NORMAL
TEMPERATURES WILL PREVAIL FOR THE LONG TERM.

&&

.AVIATION /14Z WEDNESDAY THROUGH SUNDAY/...
SHOWERS ARE EXITING THE RIDGES...WITH LOW CLOUDS AND MVFR/IFR
PERSISTING BEHIND THE PRECIP SHIELD. CONDITIONS WILL IMPROVE TO
VFR FOR MOST AREAS THIS AFTN AS THE COLD FRONT CROSSES THE REGION.

LOW PRESSURE SYSTEM WILL PUSH SLOWLY EASTWARD LATER TODAY AND VFR
CONDITIONS SHOULD PREVAIL TONIGHT THROUGH FRIDAY AS ATMOSPHERE DRIES
OUT. PATCHY EARLY MORNING FOG COULD CAUSE VISIBILITY RESTRICTIONS.

ANOTHER FRONT WILL MOVE INTO THE UPPER OHIO VALLEY SATURDAY AND
SUNDAY RAISING THE CHANCES OF SHOWERS AND THUNDERSTORMS AND POSSIBLE
MVFR CONDITIONS.

&&

.PBZ WATCHES/WARNINGS/ADVISORIES...
MD...NONE.
OH...NONE.
PA...NONE.
WV...NONE.

&&
Hazardous weather outlook, Jul 23, 5:04 AM EDT, 8 hours 9 minutes before
HAZARDOUS WEATHER OUTLOOK
NATIONAL WEATHER SERVICE PITTSBURGH PA
504 AM EDT WED JUL 23 2008

MDZ001-PAZ008-009-014>016-021>023-029>032-WVZ021>023-041-240915-
GARRETT-VENANGO-FOREST-BUTLER-CLARION-JEFFERSON PA-ALLEGHENY-
ARMSTRONG-INDIANA-WASHINGTON-WESTMORELAND-GREENE-FAYETTE-MARION-
MONONGALIA-PRESTON-TUCKER-
504 AM EDT WED JUL 23 2008

THIS HAZARDOUS WEATHER OUTLOOK IS FOR WESTERN MARYLAND...NORTHWEST
PENNSYLVANIA...SOUTHWEST PENNSYLVANIA...WEST CENTRAL PENNSYLVANIA
AND NORTHERN WEST VIRGINIA.

.DAY ONE...TODAY AND TONIGHT

THERE IS A SLIGHT RISK OF SEVERE THUNDERSTORMS TODAY. THE PRIMARY SEVERE
WEATHER THREAT WILL BE DAMAGING THUNDERTORM WINDS AND A CHANCE OF
LARGE HAIL.

.DAYS TWO THROUGH SEVEN...THURSDAY THROUGH TUESDAY

NO HAZARDOUS WEATHER IS EXPECTED AT THIS TIME.

.SPOTTER INFORMATION STATEMENT...

SPOTTER ACTIVATION IS NOT EXPECTED AT THIS TIME.

OHZ039>041-048>050-057>059-068-069-PAZ007-013-020-WVZ001>004-012-
240915-
TUSCARAWAS-CARROLL-COLUMBIANA-COSHOCTON-HARRISON-JEFFERSON OH-
MUSKINGUM-GUERNSEY-BELMONT-NOBLE-MONROE-MERCER-LAWRENCE-BEAVER-
HANCOCK-BROOKE-OHIO-MARSHALL-WETZEL-
504 AM EDT WED JUL 23 2008

THIS HAZARDOUS WEATHER OUTLOOK IS FOR EAST CENTRAL OHIO...NORTHWEST
PENNSYLVANIA...SOUTHWEST PENNSYLVANIA...WEST CENTRAL
PENNSYLVANIA...NORTHERN WEST VIRGINIA AND NORTHERN PANHANDLE OF
WEST VIRGINIA.

.DAY ONE...TODAY AND TONIGHT

NO HAZARDOUS WEATHER IS EXPECTED AT THIS TIME.

.DAYS TWO THROUGH SEVEN...THURSDAY THROUGH TUESDAY

NO HAZARDOUS WEATHER IS EXPECTED AT THIS TIME.

.SPOTTER INFORMATION STATEMENT...

SPOTTER ACTIVATION IS NOT EXPECTED AT THIS TIME.

In the hours before

Special weather statement, Jul 23, 7:19 AM EDT, 5 hours 54 minutes before
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Special weather statement, Jul 23, 9:11 AM EDT, 4 hours 2 minutes before
SPECIAL WEATHER STATEMENT
NATIONAL WEATHER SERVICE PITTSBURGH PA
911 AM EDT WED JUL 23 2008

MDZ001-WVZ023-041-231530-
GARRETT-PRESTON-TUCKER-
INCLUDING THE CITIES OF...OAKLAND MD...GRANTSVILLE...KINGWOOD...
TERRA ALTA...PARSONS...DAVIS...THOMAS
911 AM EDT WED JUL 23 2008

SHOWERS AND ISOLATED THUNDERSTORMS WILL CONTINUE TO CROSS
PRESTON...GARRETT...AND TUCKER COUNTIES FOR THE REMAINDER OF THIS
MORNING. ADDITIONAL RAINFALL OF ONE HALF TO LOCALLY ONE INCH IS
POSSIBLE. TRAVELERS SHOULD BE ALERT FOR RAPID REDUCTIONS IN
VISIBILITY...AND FOR PONDING OF WATER ON ROADWAYS.
Special weather statement, Jul 23, 11:48 AM EDT, 1 hour 25 minutes before
SPECIAL WEATHER STATEMENT
NATIONAL WEATHER SERVICE PITTSBURGH PA
1148 AM EDT WED JUL 23 2008

PAZ014-015-021-022-029>032-WVZ003-004-012-231700-
BUTLER-CLARION-ALLEGHENY-ARMSTRONG-WASHINGTON-WESTMORELAND-GREENE-
FAYETTE-OHIO-MARSHALL-WETZEL-
INCLUDING THE CITIES OF...BUTLER...ZELIENOPLE...CLARION...
PITTSBURGH METRO AREA...KITTANNING...FORD CITY...LEECHBURG...
FREEPORT...APOLLO...WASHINGTON...CANONSBURG...DONORA...
CALIFORNIA...CHARLEROI...MONONGAHELA...MCMURRAY...GREENSBURG...
NEW KENSINGTON...JEANNETTE...LATROBE...MONESSEN...WAYNESBURG...
FAIRDALE...UNIONTOWN...CONNELLSVILLE...OHIOPYLE...WHEELING...
MOUNDSVILLE...NEW MARTINSVILLE
1148 AM EDT WED JUL 23 2008

A LINE OF SHOWERS AND ISOLATED THUNDERSTORMS WILL MOVE EAST AT 20
MPH EXTENDING FROM ARMSTRONG COUNTY PENNSYLVANIA SOUTH TO WETZEL
COUNTY WEST VIRGINIA...INCLUDING THE PITTSBURGH METRO AREA. EXPECT
BRIEF HEAVY RAIN...WIND GUSTS TO 30 MPH...AND OCCASIONAL LIGHTNING
STRIKES.
Special weather statement, Jul 23, 11:59 AM EDT, 1 hour 14 minutes before
SPECIAL WEATHER STATEMENT
NATIONAL WEATHER SERVICE PITTSBURGH PA
1159 AM EDT WED JUL 23 2008

PAZ014-015-021-022-029>032-WVZ003-004-012-231700-
BUTLER-CLARION-ALLEGHENY-ARMSTRONG-WASHINGTON-WESTMORELAND-GREENE-
FAYETTE-OHIO-MARSHALL-WETZEL-
INCLUDING THE CITIES OF...BUTLER...ZELIENOPLE...CLARION...
PITTSBURGH METRO AREA...KITTANNING...FORD CITY...LEECHBURG...
FREEPORT...APOLLO...WASHINGTON...CANONSBURG...DONORA...
CALIFORNIA...CHARLEROI...MONONGAHELA...MCMURRAY...GREENSBURG...
NEW KENSINGTON...JEANNETTE...LATROBE...MONESSEN...WAYNESBURG...
FAIRDALE...UNIONTOWN...CONNELLSVILLE...OHIOPYLE...WHEELING...
MOUNDSVILLE...NEW MARTINSVILLE
1159 AM EDT WED JUL 23 2008

A LINE OF SHOWERS AND THUNDERSTORMS WILL MOVE EAST AT 20 MPH
EXTENDING FROM ARMSTRONG COUNTY PENNSYLVANIA SOUTH TO WETZEL COUNTY
WEST VIRGINIA...INCLUDING THE PITTSBURGH METRO AREA. EXPECT BRIEF
HEAVY RAIN...WIND GUSTS TO 40 MPH...AND PEA SIZED HAIL.
Special weather statement, Jul 23, 1:03 PM EDT, 10 minutes before
SPECIAL WEATHER STATEMENT
NATIONAL WEATHER SERVICE PITTSBURGH PA
103 PM EDT WED JUL 23 2008

PAZ015-016-021>023-029>032-WVZ012-022-231815-
CLARION-JEFFERSON PA-ALLEGHENY-ARMSTRONG-INDIANA-WASHINGTON-
WESTMORELAND-GREENE-FAYETTE-WETZEL-MONONGALIA-
INCLUDING THE CITIES OF...CLARION...PUNXSUTAWNEY...BROOKVILLE...
REYNOLDSVILLE...BROCKWAY...PITTSBURGH METRO AREA...KITTANNING...
FORD CITY...LEECHBURG...FREEPORT...APOLLO...INDIANA...
WASHINGTON...CANONSBURG...DONORA...CALIFORNIA...CHARLEROI...
MONONGAHELA...MCMURRAY...GREENSBURG...NEW KENSINGTON...
JEANNETTE...LATROBE...MONESSEN...WAYNESBURG...FAIRDALE...
UNIONTOWN...CONNELLSVILLE...OHIOPYLE...NEW MARTINSVILLE...
MORGANTOWN
103 PM EDT WED JUL 23 2008

A LINE OF SHOWERS AND THUNDERSTORMS WILL MOVE EAST AT 20 MPH
EXTENDING FROM JEFFERSON COUNTY PENNSYLVANIA SOUTH TO WETZEL COUNTY
WEST VIRGINIA. THE STRONGER STORMS ARE CAPABLE OF PRODUCING WIND
GUSTS TO 40 MPH AND DIME SIZED HAIL. RAINFALL OF ONE HALF TO
ONE INCH IS LIKELY WITH THESE STORMS...PRODUCING SIGNIFICANT
PONDING OF WATER ON ROADWAYS.

The office that day

Everything else NWS Pittsburgh, PA issued on the same UTC day.

IssuedProductOfficeCountiesLasted
Jul 22, 8:04 PM EDTTornado WarningPBZBeaver, Lawrence41 min
Jul 22, 8:27 PM EDTTornado WarningPBZBeaver, Butler, Lawrence48 min
Jul 23, 1:42 PM EDTSevere Thunderstorm WarningPBZIndiana, Westmoreland63 min
Jul 23, 2:00 PM EDTSevere Thunderstorm WarningPBZIndiana, Jefferson60 min

Nearby

Flash Flood Warnings in Pennsylvania, 2008Every flash flood warning in 2008

Sources

The product and its follow-ups from the Iowa Environmental Mesonet's archive of National Weather Service and Storm Prediction Center text; the sounding from the Mesonet's radiosonde archive; radar from the NEXRAD Level II archive.