Alert archive / Maryland / Severe Thunderstorm Warnings in 2011

Severe Thunderstorm Warning 183, NWS Philadelphia/Mount Holly

July 19, 2011Cecil County, Maryland; Chester County, Pennsylvania

NWS Philadelphia/Mount Holly issued this severe thunderstorm warning at Jul 19, 2011, 8:07 PM EDT for Cecil County, Maryland; Chester County, Pennsylvania. It was in force for 53 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: Jul 19, 2011, 8:07 PM EDT (00:07 UTC)
Expired: Jul 19, 2011, 9:00 PM EDT
In force: 53 min
Issued by: NWS Philadelphia/Mount Holly
Area: Storm-based polygon

Counties Cecil County, MD, Chester County, PA

The radar

The Dover AFB radar (KDOX), 105 km from the middle of the area, began a volume at 00:09 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
Jul 19, 8:35 PM EDT	TSTM WND DMG	Conowingo, MD	TREE DOWN ACROSS DOCTOR JACK ROAD

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

The nearest sounding before it

Washington/Dulle, VA (KIAD), launched 00:00Z, 0.1 hours before the alert went out and 137 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: 2824 J/kg
Mixed-layer CIN: -1 J/kg
Mixed-layer LCL: 1156 m above ground
0-6 km bulk shear: 26 kt
0-1 km storm-relative helicity: 22 m²/s²
0-3 km storm-relative helicity: 26 m²/s²
Significant tornado parameter: 0.1
Supercell composite: 0.8

Open this sounding in Storm Lab

The text

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

103 
WUUS51 KPHI 200007
SVRPHI
MDC015-PAC029-200100-
/O.NEW.KPHI.SV.W.0183.110720T0007Z-110720T0100Z/

BULLETIN - EAS ACTIVATION REQUESTED
SEVERE THUNDERSTORM WARNING
NATIONAL WEATHER SERVICE MOUNT HOLLY NJ
807 PM EDT TUE JUL 19 2011

THE NATIONAL WEATHER SERVICE IN MOUNT HOLLY NJ HAS ISSUED A

* SEVERE THUNDERSTORM WARNING FOR...
  NORTHWESTERN CECIL COUNTY IN NORTHEAST MARYLAND...
  EXTREME SOUTHWESTERN CHESTER COUNTY IN SOUTHEAST PENNSYLVANIA...

* UNTIL 900 PM EDT

* AT 805 PM EDT...NATIONAL WEATHER SERVICE DOPPLER RADAR INDICATED A
  SEVERE THUNDERSTORM.  THIS STORM WAS LOCATED NEAR GLEN ROY...OR 19
  MILES NORTHWEST OF NEWARK...AND MOVING SOUTH AT 15 MPH.

* THE SEVERE THUNDERSTORM WILL BE NEAR...
  ROCK SPRINGS AROUND 830 PM EDT...
  RISING SUN AND CALVERT AROUND 835 PM EDT...
  RICHARDSMERE AND FARMINGTON AROUND 840 PM EDT...
  WEST NOTTINGHAM AND CONOWINGO AROUND 845 PM EDT... 

PRECAUTIONARY/PREPAREDNESS ACTIONS...

IN ADDITION TO LARGE HAIL AND DAMAGING WINDS...CONTINUOUS CLOUD TO
GROUND LIGHTNING IS OCCURRING WITH THIS STORM. MOVE INDOORS
IMMEDIATELY! LIGHTNING IS ONE OF NATURES GREATEST KILLERS.
REMEMBER...IF YOU CAN HEAR THUNDER...YOU ARE CLOSE ENOUGH TO BE
STRUCK BY LIGHTNING.

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

&&

LAT...LON 3973 7623 3974 7613 3980 7606 3979 7599
      3970 7596 3948 7597 3950 7601 3951 7599
      3953 7600 3955 7603 3954 7607 3956 7610
      3965 7617 3970 7624
TIME...MOT...LOC 0007Z 005DEG 11KT 3979 7607

$$

JJM

The office that day

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

Issued	Product	Office	Counties	Lasted
Jul 19, 9:27 PM EDT	Special Weather Statement	PHI	Caroline, Kent, Queen Anne's, Talbot	93 min
Jul 20, 4:04 AM EDT	Excessive Heat Watch	PHI	Caroline, Cecil, Kent, Queen Anne's, Talbot	11 hr
Jul 20, 5:22 PM EDT	Special Weather Statement	PHI	Monroe	53 min

Nearby

Severe Thunderstorm Warnings in Maryland, 2011 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.