Alert archive / Pennsylvania / Severe Thunderstorm Warnings in 2008

Severe Thunderstorm Warning 224, NWS Philadelphia/Mount Holly

August 10, 2008Berks County, Chester County, Montgomery County, Pennsylvania

NWS Philadelphia/Mount Holly issued this severe thunderstorm warning at Aug 10, 2008, 1:10 PM EDT for Berks County, Chester County, Montgomery County, Pennsylvania. It was in force for 65 min. 1 report 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: Aug 10, 2008, 1:10 PM EDT (17:10 UTC)
Expired: Aug 10, 2008, 2:15 PM EDT
In force: 65 min
Issued by: NWS Philadelphia/Mount Holly
Area: Storm-based polygon

Counties Berks County, PA, Chester County, PA, Montgomery County, PA

The radar

The Philadelphia radar (KDIX), 138 km from the middle of the area, began a volume at 17:12 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
Aug 10, 1:56 PM EDT	HAIL 0.88	3 W Elverson, PA

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

The watch it was issued in

The SPC watch in force over the same counties when this warning went out.

Issued	Product	Office	Lasted
Aug 10, 10:46 AM EDT	Severe Thunderstorm Watch	SPC	10 hr

The nearest sounding before it

Washington/Dulle, VA (KIAD), launched 12:00Z, 5.2 hours before the alert went out and 192 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: 771 J/kg
Mixed-layer CIN: -66 J/kg
Mixed-layer LCL: 923 m above ground
0-6 km bulk shear: 25 kt
0-1 km storm-relative helicity: 3 m²/s²
0-3 km storm-relative helicity: 85 m²/s²
Significant tornado parameter: 0.0
Supercell composite: 0.8

Open this sounding in Storm Lab

The text

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

000 
WUUS51 KPHI 101710
SVRPHI
PAC011-029-091-101815-
/O.NEW.KPHI.SV.W.0224.080810T1710Z-080810T1815Z/

BULLETIN - EAS ACTIVATION REQUESTED
SEVERE THUNDERSTORM WARNING
NATIONAL WEATHER SERVICE MOUNT HOLLY NJ
110 PM EDT SUN AUG 10 2008

THE NATIONAL WEATHER SERVICE IN MOUNT HOLLY NJ HAS ISSUED A

* SEVERE THUNDERSTORM WARNING FOR...
  SOUTHERN BERKS COUNTY IN EASTERN PENNSYLVANIA...
  NORTH CENTRAL CHESTER COUNTY IN SOUTHEAST PENNSYLVANIA...
  EXTREME WEST CENTRAL MONTGOMERY COUNTY IN SOUTHEAST PENNSYLVANIA...

* UNTIL 215 PM EDT

* AT 103 PM EDT...NATIONAL WEATHER SERVICE DOPPLER RADAR INDICATED A
  SEVERE THUNDERSTORM.  THIS STORM WAS LOCATED 7 MILES NORTHWEST OF
  ELVERSON...OR ABOUT 8 MILES SOUTH OF READING...AND MOVING NORTHEAST
  AT 20 MPH. LARGE HAIL AND DAMAGING WINDS CAN BE EXPECTED WITH THIS 
  THUNDERSTORM. OTHER THUNDERSTORMS ARE DEVELOPING IN THE WARNED     
  AREA AND WILL BE CAPABLE OF PRODUCING LARGE HAIL AND DAMAGING      
  WINDS.

* OTHER LOCATIONS IN THE WARNING INCLUDE BUT ARE NOT LIMITED TO
  LEESPORT...BIRDSBORO AND CEDARVILLE

A SEVERE THUNDERSTORM WATCH REMAINS IN EFFECT UNTIL 700 PM SUNDAY
EVENING FOR DELAWARE AND NORTHEASTERN MARYLAND AND NEW JERSEY AND
EASTERN PENNSYLVANIA.

LAT...LON 4050 7600 4025 7563 4007 7582 4014 7591
      4014 7590 4017 7593 4028 7611 4036 7621
      4037 7621
TIME...MOT...LOC 1709Z 240DEG 22KT 4023 7591

$$

JJM

1 follow-up statement

000 
WWUS51 KPHI 101810
SVSPHI

SEVERE WEATHER STATEMENT
NATIONAL WEATHER SERVICE MOUNT HOLLY NJ
210 PM EDT SUN AUG 10 2008

PAC011-029-091-101817-
/O.EXP.KPHI.SV.W.0224.000000T0000Z-080810T1815Z/
CHESTER PA-MONTGOMERY PA-BERKS PA-
207 PM EDT SUN AUG 10 2008

...THE SEVERE THUNDERSTORM WARNING FOR SOUTHERN BERKS...EXTREME WEST
CENTRAL MONTGOMERY AND NORTH CENTRAL CHESTER COUNTIES WILL EXPIRE AT
215 PM EDT...

THE SEVERE THUNDERSTORMS CONTINUE TO SLIDE TO THE EAST OF THIS 
REGION, THEREFORE THIS WARNING HAS BEEN ALLOWED TO EXPIRE AT 215 PM.

A SEPARATE SEVERE THUNDERSTORM WARNING HOWEVER REMAINS EFFECT FOR 
CHESTER AND MONTGOMERY COUNTIES UNTIL 245 PM AS THE STORMS CONTINUE 
TO TRACK ACROSS THESE AREAS.

A SEVERE THUNDERSTORM WATCH REMAINS IN EFFECT UNTIL 700 PM EDT SUNDAY
EVENING FOR DELAWARE AND NORTHEASTERN MARYLAND AND NEW JERSEY AND
EASTERN PENNSYLVANIA.

LAT...LON 4050 7600 4025 7563 4007 7582 4014 7591
      4014 7590 4017 7593 4028 7611 4036 7621
      4037 7621
TIME...MOT...LOC 1807Z 240DEG 22KT 4018 7573

$$

GORSE

The office that day

Everything else NWS Philadelphia/Mount Holly issued on the same UTC day.

Issued	Product	Office	Counties	Lasted
Aug 10, 10:18 AM EDT	Severe Thunderstorm Warning	PHI	Chester	57 min
Aug 10, 10:44 AM EDT	Severe Thunderstorm Warning	PHI	Delaware	61 min
Aug 10, 11:09 AM EDT	Severe Thunderstorm Warning	PHI	Chester, Delaware, Montgomery, Philadelphia	66 min
Aug 10, 11:32 AM EDT	Areal Flood Advisory	PHI	Chester, Delaware	3 hr
Aug 10, 11:46 AM EDT	Severe Thunderstorm Warning	PHI	Delaware	59 min
Aug 10, 12:09 PM EDT	Tornado Warning	PHI	Delaware	36 min
Aug 10, 12:17 PM EDT	Flash Flood Warning	PHI	Chester, Delaware, Montgomery	4 hr
Aug 10, 12:21 PM EDT	Severe Thunderstorm Warning	PHI	Berks, Bucks, Lehigh, Montgomery	84 min
Aug 10, 12:40 PM EDT	Severe Thunderstorm Warning	PHI	Delaware, Philadelphia	95 min
Aug 10, 1:05 PM EDT	Severe Thunderstorm Warning	PHI	Bucks, Carbon, Lehigh, Monroe, Northampton	115 min
Aug 10, 1:47 PM EDT	Severe Thunderstorm Warning	PHI	Chester, Montgomery	58 min
Aug 10, 3:05 PM EDT	Flash Flood Warning	PHI	Chester	3 hr
Aug 10, 3:35 PM EDT	Severe Thunderstorm Warning	PHI	Berks	40 min
Aug 10, 4:45 PM EDT	Severe Thunderstorm Warning	PHI	Chester	75 min
Aug 10, 5:25 PM EDT	Areal Flood Advisory	PHI	Berks, Montgomery	110 min
Aug 10, 5:45 PM EDT	Severe Thunderstorm Warning	PHI	Chester, Delaware	75 min
Aug 10, 5:59 PM EDT	Areal Flood Advisory	PHI	Chester, Delaware	2 hr
Aug 10, 6:45 PM EDT	Areal Flood Advisory	PHI	Philadelphia	2 hr

Nearby

Severe Thunderstorm Warnings in Pennsylvania, 2008 Every severe thunderstorm 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; local storm reports from the same archive; the sounding from the Mesonet's radiosonde archive; radar from the NEXRAD Level II archive.