Alert archive / Pennsylvania / Severe Thunderstorm Warnings in 2011

Severe Thunderstorm Warning 36, NWS Pittsburgh, PA

April 25, 20114 counties in Pennsylvania

NWS Pittsburgh, PA issued this severe thunderstorm warning at Apr 25, 2011, 1:59 PM EDT for 4 counties in Pennsylvania. It was in force for 46 min. 2 reports came from inside the area while it was in force.

The area

The outline as issued, with what was reported inside it.

The facts

Issued: Apr 25, 2011, 1:59 PM EDT (17:59 UTC)
Expired: Apr 25, 2011, 2:45 PM EDT
In force: 46 min
Issued by: NWS Pittsburgh, PA
Area: Storm-based polygon

Counties Armstrong County, PA, Butler County, PA, Clarion County, PA, Jefferson County, PA

The radar

The Pittsburgh radar (KPBZ), 97 km from the middle of the area, began a volume at 18:01 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.

What was reported inside it

Time	Report	Where	Remark
Apr 25, 2:52 PM EDT	TSTM WND DMG	Coolspring, PA	TREES AND POWER LINES DOWN IN COOLSPRING.
Apr 25, 2:55 PM EDT	TSTM WND DMG	Ringgold, PA	TREES AND POWERLINES BLOCKING ROADWAY ON HUNGRY HOOK ROAD.

Local storm reports filed while the alert was in force, from inside its polygon or its counties.

Did it verify

Not verified. The Iowa Environmental Mesonet's Cow found no qualifying storm report inside this severe thunderstorm warning while it was in force. That is not proof nothing happened: reports are thin where few people live.

Cow counts a report within 15 km of the polygon while the warning was in force: a tornado for a tornado warning; hail of 1 inch or more, a gust of 58 mph or more or wind damage for a severe thunderstorm warning; a flash flood report for a flash flood warning.

The nearest sounding before it

Pittsburgh, PA (KPIT), launched 12:00Z, 6.0 hours before the alert went out and 96 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-p

Temperature in red, dew point in green, the mixed-layer parcel dashed.

Hodograph

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: 4 J/kg
Mixed-layer CIN: -53 J/kg
Mixed-layer LCL: 698 m above ground
0-6 km bulk shear: 42 kt
0-1 km storm-relative helicity: 66 m²/s²
0-3 km storm-relative helicity: 87 m²/s²
Significant tornado parameter: 0.0
Supercell composite: 0.0

Open this sounding in Storm Lab

The text

As transmitted, in the capitals the NWS used until 2016.

617 
WUUS51 KPBZ 251759
SVRPBZ
PAC005-019-031-065-251845-
/O.NEW.KPBZ.SV.W.0036.110425T1759Z-110425T1845Z/

BULLETIN - EAS ACTIVATION REQUESTED
SEVERE THUNDERSTORM WARNING
NATIONAL WEATHER SERVICE PITTSBURGH PA
159 PM EDT MON APR 25 2011

THE NATIONAL WEATHER SERVICE IN PITTSBURGH HAS ISSUED A

* SEVERE THUNDERSTORM WARNING FOR...
  NORTHERN ARMSTRONG COUNTY IN WEST CENTRAL PENNSYLVANIA...
  EAST CENTRAL BUTLER COUNTY IN WEST CENTRAL PENNSYLVANIA...
  SOUTHWESTERN JEFFERSON COUNTY IN WEST CENTRAL PENNSYLVANIA...
  SOUTHERN CLARION COUNTY IN WEST CENTRAL PENNSYLVANIA...

* UNTIL 245 PM EDT

* AT 157 PM EDT...NATIONAL WEATHER SERVICE DOPPLER RADAR INDICATED A
  SEVERE THUNDERSTORM CAPABLE OF PRODUCING QUARTER SIZE HAIL...AND
  DAMAGING WINDS IN EXCESS OF 60 MPH.  THIS STORM WAS LOCATED NEAR
  EAST BRADY...MOVING NORTHEAST AT 50 MPH.

* OTHER LOCATIONS IN THE WARNING INCLUDE BUT ARE NOT LIMITED TO  
  KITTANNING...         CHICORA...            BRADYS BEND...
  EAST BRADY...         RIMERSBURG...         MUFF...
  NEW BETHLEHEM...      LIMESTONE...          DORA...
  SUMMERVILLE...        BROOKVILLE...        
  CLEAR CREEK STATE PARK...

PRECAUTIONARY/PREPAREDNESS ACTIONS...

IF YOU ARE IN THE PATH OF THIS STORM...PREPARE IMMEDIATELY FOR
DAMAGING WINDS...DESTRUCTIVE HAIL...AND DEADLY CLOUD TO GROUND
LIGHTNING. PEOPLE OUTSIDE SHOULD MOVE TO A SHELTER...PREFERABLY
INSIDE A STRONG BUILDING BUT AWAY FROM WINDOWS.

PLEASE REPORT HAIL...STRONG WINDS OR WIND DAMAGE TO THE NATIONAL
WEATHER SERVICE BY CALLING TOLL FREE. 1-877-633-6772...WHEN YOU CAN
DO SO SAFELY.

&&

LAT...LON 4101 7883 4091 7918 4092 7922 4090 7922
      4077 7967 4093 7981 4134 7909
TIME...MOT...LOC 1759Z 238DEG 41KT 4093 7959

$$

WOODRUM

2 follow-up statements

253 
WWUS51 KPBZ 251819
SVSPBZ

SEVERE WEATHER STATEMENT
NATIONAL WEATHER SERVICE PITTSBURGH PA
219 PM EDT MON APR 25 2011

PAC019-251828-
/O.CAN.KPBZ.SV.W.0036.000000T0000Z-110425T1845Z/
BUTLER PA-
219 PM EDT MON APR 25 2011

...THE SEVERE THUNDERSTORM WARNING FOR BUTLER COUNTY IS CANCELLED...

LAT...LON 4101 7883 4091 7917 4092 7922 4088 7931
      4084 7951 4096 7964 4134 7909
TIME...MOT...LOC 1818Z 240DEG 31KT 4095 7947

$$

PAC005-031-065-251845-
/O.CON.KPBZ.SV.W.0036.000000T0000Z-110425T1845Z/
ARMSTRONG PA-JEFFERSON PA-CLARION PA-
219 PM EDT MON APR 25 2011

...A SEVERE THUNDERSTORM WARNING REMAINS IN EFFECT UNTIL 245 PM EDT
FOR CLARION...JEFFERSON AND ARMSTRONG COUNTIES IN WEST CENTRAL
PENNSYLVANIA...

AT 214 PM EDT...NATIONAL WEATHER SERVICE DOPPLER RADAR CONTINUED TO
INDICATE A SEVERE THUNDERSTORM CAPABLE OF PRODUCING QUARTER SIZE
HAIL...AND DAMAGING WINDS IN EXCESS OF 60 MPH.  THIS STORM WAS
LOCATED NEAR RIMER...MOVING NORTHEAST AT 35 MPH.

* OTHER LOCATIONS IN THE WARNING INCLUDE BUT ARE NOT LIMITED TO  
  RIMERSBURG...         MUFF...               NEW BETHLEHEM...
  LIMESTONE...          DORA...               SUMMERVILLE...
  CLEAR CREEK STATE PARK...                   BROOKVILLE...

LAT...LON 4101 7883 4091 7917 4092 7922 4088 7931
      4084 7951 4096 7964 4134 7909
TIME...MOT...LOC 1818Z 240DEG 31KT 4095 7947

$$

WOODRUM

339 
WWUS51 KPBZ 251834
SVSPBZ

SEVERE WEATHER STATEMENT
NATIONAL WEATHER SERVICE PITTSBURGH PA
234 PM EDT MON APR 25 2011

PAC005-031-065-251845-
/O.CON.KPBZ.SV.W.0036.000000T0000Z-110425T1845Z/
ARMSTRONG PA-JEFFERSON PA-CLARION PA-
234 PM EDT MON APR 25 2011

...A SEVERE THUNDERSTORM WARNING REMAINS IN EFFECT UNTIL 245 PM EDT
FOR CLARION...JEFFERSON AND ARMSTRONG COUNTIES IN WEST CENTRAL
PENNSYLVANIA...

AT 231 PM EDT...A SEVERE THUNDERSTORM WAS REPORTED CAPABLE OF
PRODUCING QUARTER SIZE HAIL...AND DAMAGING WINDS IN EXCESS OF 60 MPH.
 THIS STORM WAS LOCATED NEAR SOUTH BETHLEHEM...MOVING NORTHEAST AT 35
MPH.

* OTHER LOCATIONS IN THE WARNING INCLUDE BUT ARE NOT LIMITED TO   NEW
  BETHLEHEM...      DORA...               SUMMERVILLE...
  BROOKVILLE...

LAT...LON 4093 7936 4104 7943 4128 7906 4101 7883
      4091 7917 4092 7922 4088 7931
TIME...MOT...LOC 1834Z 240DEG 31KT 4102 7931

$$

WOODRUM

What forecasters said that day

The local office's own words before this severe thunderstorm 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 severe thunderstorm warning went out at Apr 25, 12:54 PM EDT, 1 hour 5 minutes earlier.

Area forecast discussion, Apr 25, 12:54 PM EDT, 1 hour 5 minutes before

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE PITTSBURGH PA
1254 PM EDT MON APR 25 2011

.SYNOPSIS...
A WARM FRONT NORTH OF INTERSTATE 80 THIS AFTERNOON WILL CONTINUE
TO MOVE NORTH WITH WARM AND HUMID AIR ACROSS THE REGION. SCATTERED
SHOWERS AND THUNDERSTORMS WILL BECOME MORE WIDESPREAD LATER THIS
AFTERNOON INTO EARLY EVENING. THE CHANCE OF SHOWERS AND
THUNDERSTORMS WITH UNSEASONABLY WARM TEMPERATURES WILL CONTINUE
UNTIL A COLD FRONT PASSES ON THURSDAY. BEHIND THIS FRONT
SEASONABLE TEMPERATURES CAN BE EXPECTED FOR LATE WEEK.

&&

.NEAR TERM /THROUGH TONIGHT/...
EARLY AFTERNOON UPDATE TO RAISE MAX TEMPS A DEGREE IN THE SOUTH
AND RECONFIGURE POPS TO LOWER SOUTHEAST RIDGES AND TOWARD LIKELY
LATE DAY IN EASTERN OHIO AS UPPER LEVEL IMPULSE MOVES NORTHEAST
FROM SOUTHWEST OHIO. LOWER POPS LATER THIS EVENING AS THIS AREA
MOVES EAST.

&&

.SHORT TERM /TUESDAY THROUGH TUESDAY NIGHT/...
CENTRAL PLAINS TROUGH IS FORECAST TO DIG TOWARD THE WESTERN GREAT
LAKES/UPPER MISSISSIPPI VALLEY REGION AND CUTOFF ON TUESDAY. THAT
PATTERN WILL YIELD SPLIT FLOW WITH FAST SOUTHERN STREAM OVER THE
UPPER OHIO VALLEY REGION. RESULTING WARMTH AND MOISTURE WILL
DESTABILIZE THE ATMOSPHERE WITH MODERATE TO HIGH LEVELS OF SHEAR
IN THE RAPID FLOW. AS SHORTWAVES MOVE THROUGH THIS PATTERN,
THUNDERSTORMS MAY BE EXPECTED INTO MID WEEK WITH POTENTIAL FOR
A SLIGHT RISK OF SEVERE STORMS THROUGH WEDNESDAY.
TEMPERATURES WILL REMAIN WELL ABOVE NORMAL.

&&

.LONG TERM /WEDNESDAY THROUGH SUNDAY/...
A COLD FRONT WILL CROSS THE AREA WEDNESDAY NIGHT INTO THURSDAY WITH
LIKELY POPS FOR ALL AREAS. MODELS BEGIN TO DIFFER BY THURSDAY
NIGHT ON HANDLING THE POST FRONTAL UPPER TROUGH...WITH THE ECMWF
DIGGING THE TROUGH ACROSS THE GREAT LAKES KEEPING AN UNSETTLED
PATTERN ACROSS THE REGION THROUGH FRIDAY...AND THE GFS MORE
PROGRESSIVE PUSHING THE UPPER TROUGH INTO EASTERN CANADA THURSDAY
NIGHT. WILL SPLIT THE DIFFERENCE...WITH LINGERING LOW END CHANCE
POPS POST FRONTAL INTO THURSDAY NIGHT...WITH RESIDUAL PRECIP
EXITING ON FRIDAY. SHORTWAVE RIDGING WILL BRING DRY CONDITIONS FOR
SATURDAY...WITH ANOTHER SYSTEM PROGGED TO ENTER THE REGION SUNDAY
FOR A CHANCE OF SHOWERS. SEASONABLY COOL TEMPERATURES LATE IN THE
WEEK WILL WARM TO NEAR NORMAL FOR THE UPCOMING WEEKEND.

&&

.AVIATION /18Z MONDAY THROUGH SATURDAY/...
VFR CONDITIONS WILL PREVAIL FOR THE MAJORITY TODAY AS A FRONTAL
BOUNDARY ALONG A KFKL-KDUJ LINE PUSHES SLOWLY NORTHWARD. ALONG THE
BOUNDARY NEAR LIFR CEILINGS AT KDUJ AND MVFR AT KFKL WILL LIFT TO
VFR EARLY THIS AFTERNOON. SCATTERED THUNDERSTORMS WILL DEVELOP IN
THE WARM SECTOR THIS AFTERNOON. TEMPO GROUPS FOR -TSRA ARE FORECAST
KHLG/KZZV WITH THE MOST CONFIDENCE THERE. THE OTHER TERMINALS HAVE
PREVAILING CB GROUPS AT THE MOMENT WHICH MAY NEED TEMPO GROUPS ADDED
IN  FUTURE UPDATES.

CONDITIONS WILL SOMEWHAT DETERIORATE TONIGHT, AS ANOTHER WAVE MOVES
THROUGH THE UPPER OHIO VALLEY. EXPECT ANOTHER ROUND OF RESTRICTIONS
DURING THE EVENING AND EARLY OVERNIGHT HOURS. THIS MAY BE THE BEST
TIME TO SEE A LINE OF CONVECTION DEVELOP.

THE FRONTAL BOUNDARY WILL CONTINUE TO MEANDER ACROSS THE REGION FOR
TUESDAY AND WEDNESDAY...WITH THE SYSTEMS COLD FRONT CROSSING THE
AREA WEDNESDAY NIGHT INTO THURSDAY. EXPECT PERIODS OF SHOWERS AND
RESTRICTIONS...WITH GREATER COVERAGE LATE WEDNESDAY AFTERNOON INTO
THURSDAY ALONG/IMMEDIATELY IN THE WAKE OF THE COLD FRONT. RESIDUAL
SHOWERS AND RESTRICTIONS ARE LIKELY LATE THURSDAY INTO FRIDAY AS
UPPER LEVEL LOW PRESSURE GRADUALLY EXITS TO THE NORTHEAST. HIGH
PRESSURE AND VFR ARE EXPECTED TO RETURN TO THE AREA FRIDAY.

&&

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

&&

Hazardous weather outlook, Apr 25, 4:31 AM EDT, 9 hours 28 minutes before

HAZARDOUS WEATHER OUTLOOK
NATIONAL WEATHER SERVICE PITTSBURGH PA
431 AM EDT MON APR 25 2011

MDZ001-OHZ039>041-048>050-057>059-068-069-PAZ007>009-013>016-020>023-
029-031-073>076-WVZ001>004-012-021>023-041-260845-
GARRETT-TUSCARAWAS-CARROLL-COLUMBIANA-COSHOCTON-HARRISON-
JEFFERSON OH-MUSKINGUM-GUERNSEY-BELMONT-NOBLE-MONROE-MERCER-VENANGO-
FOREST-LAWRENCE-BUTLER-CLARION-JEFFERSON PA-BEAVER-ALLEGHENY-
ARMSTRONG-INDIANA-WASHINGTON-GREENE-WESTMORELAND-WESTMORELAND RIDGES-
FAYETTE-FAYETTE RIDGES-HANCOCK-BROOKE-OHIO-MARSHALL-WETZEL-MARION-
MONONGALIA-PRESTON-TUCKER-
431 AM EDT MON APR 25 2011

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

.DAY ONE...TODAY AND TONIGHT.

THERE IS A SLIGHT RISK OF SEVERE THUNDERSTORMS LATE THIS AFTERNOON
INTO THIS EVENING. THE PRIMARY SEVERE WEATHER RISK WILL BE DAMAGING
THUNDERSTORM WINDS AND LARGE HAIL.

.DAYS TWO THROUGH SEVEN...TUESDAY THROUGH SUNDAY.

THERE IS A SLIGHT RISK FOR SEVERE THUNDERSTORMS ON TUESDAY AND
WEDNESDAY. SEVERE THREATS ON BOTH DAYS WILL AGAIN COME PRIMARILY
FROM DAMAGING WIND GUSTS AND LARGE HAIL.

.SPOTTER INFORMATION STATEMENT...

WEATHER SPOTTERS ARE ENCOURAGED TO REPORT SIGNIFICANT WEATHER
CONDITIONS ACCORDING TO STANDARD OPERATING PROCEDURES.

In the hours before

Special weather statement, Apr 25, 1:39 PM EDT, 20 minutes before

SPECIAL WEATHER STATEMENT
NATIONAL WEATHER SERVICE PITTSBURGH PA
139 PM EDT MON APR 25 2011

PAZ014-015-022-251815-
ARMSTRONG PA-BUTLER PA-CLARION PA-
139 PM EDT MON APR 25 2011

...A STRONG THUNDERSTORM TO MOVE THROUGH THE FOLLOWING
COUNTIES...ARMSTRONG...BUTLER AND CLARION...

AT 136 PM EDT NATIONAL WEATHER SERVICE DOPPLER RADAR IN PITTSBURGH
INDICATED STRONG THUNDERSTORMS 5 MILES WEST OF SAXONBURG...MOVING
NORTHEAST AT 45 MPH. THIS STORM WILL BE CAPABLE OF PRODUCING SMALL
HAIL AND WINDS GUSTING UP TO 40 MPH.

SOME LOCATIONS THAT WILL BE IMPACTED BY THESE STORMS INCLUDE...
  SAXONBURG...          BUTLER...             CHICORA...
  BRADYS BEND...        EAST BRADY...

KEEP AN EYE TO THE SKY AND MOVE TO A SAFE PLACE IF THUNDERSTORMS
APPROACH.

PLEASE REPORT HAIL...STRONG WINDS OR WIND DAMAGE TO THE NATIONAL
WEATHER SERVICE BY CALLING TOLL FREE...1-877-633-6772.

LAT...LON 4108 7968 4090 7945 4068 7991 4081 8005

WOODRUM

The office that day

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

Issued	Product	Office	Counties	Lasted
Apr 25, 1:39 PM EDT	Special Weather Statement	PBZ	Butler	36 min
Apr 25, 2:37 PM EDT	Tornado Warning	PBZ	Armstrong, Clarion, Jefferson	23 min
Apr 25, 2:59 PM EDT	Severe Thunderstorm Warning	PBZ	Jefferson	30 min
Apr 25, 4:54 PM EDT	Severe Thunderstorm Warning	PBZ	Beaver, Lawrence	36 min
Apr 25, 5:03 PM EDT	Special Weather Statement	PBZ	Forest, Venango	57 min
Apr 25, 5:23 PM EDT	Severe Thunderstorm Warning	PBZ	Forest	37 min
Apr 25, 5:24 PM EDT	Special Weather Statement	PBZ	Beaver	51 min
Apr 25, 5:50 PM EDT	Tornado Warning	PBZ	Forest	25 min
Apr 25, 5:59 PM EDT	Special Weather Statement	PBZ	Allegheny	31 min
Apr 25, 6:25 PM EDT	Special Weather Statement	PBZ	Armstrong	35 min
Apr 25, 6:36 PM EDT	Special Weather Statement	PBZ	Allegheny	24 min
Apr 25, 6:58 PM EDT	Special Weather Statement	PBZ	Jefferson	32 min

Nearby

Severe Thunderstorm Warnings in Pennsylvania, 2011 Every severe thunderstorm warning in 2011

Sources

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