Alert archive / Pennsylvania / Special Weather Statements in 2017

Special Weather Statement, NWS Philadelphia/Mount Holly

July 17, 2017Chester County, Pennsylvania

NWS Philadelphia/Mount Holly issued this special weather statement at Jul 17, 2017, 5:55 PM EDT for Chester County, Pennsylvania. It was in force for 50 min. No storm report in the archive falls inside the area while it was in force.

The area

The outline as issued.

The facts

Issued: Jul 17, 2017, 5:55 PM EDT (21:55 UTC)
Expired: Jul 17, 2017, 6:45 PM EDT
In force: 50 min
Issued by: NWS Philadelphia/Mount Holly

County Chester County, PA

The radar

The Dover AFB radar (KDOX), 104 km from the middle of the area, began a volume at 21:57 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, 9.9 hours before the alert went out and 176 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: 1198 J/kg
Mixed-layer CIN: -50 J/kg
Mixed-layer LCL: 1021 m above ground
0-6 km bulk shear: 23 kt
0-1 km storm-relative helicity: 40 m²/s²
0-3 km storm-relative helicity: 28 m²/s²
Significant tornado parameter: 0.0
Supercell composite: 0.6

Open this sounding in Storm Lab

The text

As transmitted.

574 
WWUS81 KPHI 172155
SPSPHI

Special Weather Statement
National Weather Service Mount Holly NJ
555 PM EDT MON JUL 17 2017

DEZ001-MDZ008-PAZ070-101-102-172245-
New Castle-Cecil-Delaware-Western Chester-Eastern Chester-
555 PM EDT MON JUL 17 2017

...A STRONG THUNDERSTORM WILL AFFECT NORTHERN NEW CASTLE...
NORTHEASTERN CECIL...SOUTHERN CHESTER AND SOUTHWESTERN DELAWARE
COUNTIES...

At 555 PM EDT, a strong thunderstorm was located over Kemblesville,
or 9 miles northwest of Newark, moving east at 30 mph.

Winds up to 40 mph and pea size hail are possible with this storm.

Locations impacted include...
Wilmington, Newark, Elkton, Calvert, Westtown, Elsmere, Kennett
Square, New Castle, Oxford, West Grove, Newport, Arden, Blake,
Stanton, Cheyney, Talleyville, Elam, Chelsea, Bay View and
Greenville.

Torrential rainfall is also occurring with this storm, and may cause
localized flooding. Do not drive your vehicle through flooded
roadways.

Frequent cloud to ground lightning is occurring with this storm.
Lightning can strike 10 miles away from a thunderstorm. Seek a safe
shelter inside a building or vehicle.

LAT...LON 3981 7602 3998 7551 3980 7541 3977 7546
      3974 7547 3971 7550 3972 7552 3967 7555
      3962 7562 3964 7598
TIME...MOT...LOC 2155Z 249DEG 27KT 3978 7587 

$$

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The office that day

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

Issued	Product	Office	Counties	Lasted
Jul 17, 3:56 PM EDT	Areal Flood Advisory	PHI	Hunterdon, Warren	4 hr
Jul 17, 4:16 PM EDT	Special Weather Statement	PHI	Gloucester	44 min
Jul 17, 4:35 PM EDT	Areal Flood Advisory	PHI	Sussex, Warren	115 min
Jul 17, 4:40 PM EDT	Special Weather Statement	PHI	Warren	65 min
Jul 17, 4:44 PM EDT	Areal Flood Advisory	PHI	Burlington, Camden, Gloucester	3 hr
Jul 17, 5:00 PM EDT	Special Weather Statement	PHI	Warren	30 min
Jul 17, 5:31 PM EDT	Areal Flood Advisory	PHI	Hunterdon, Morris, Sussex, Warren	119 min
Jul 17, 5:51 PM EDT	Special Weather Statement	PHI	Hunterdon	39 min
Jul 17, 6:12 PM EDT	Special Weather Statement	PHI	Morris	33 min
Jul 17, 6:33 PM EDT	Flash Flood Warning	PHI	Morris	117 min
Jul 17, 6:39 PM EDT	Special Weather Statement	PHI	Hunterdon	51 min
Jul 17, 6:44 PM EDT	Special Weather Statement	PHI	Morris	46 min
Jul 17, 1:09 PM EDT	Special Weather Statement	PHI	Lehigh	36 min
Jul 17, 1:20 PM EDT	Severe Thunderstorm Warning	PHI	Berks	40 min
Jul 17, 1:24 PM EDT	Areal Flood Advisory	PHI	Berks	5 hr
Jul 17, 1:41 PM EDT	Flash Flood Warning	PHI	Berks	7 hr
Jul 17, 1:57 PM EDT	Special Weather Statement	PHI	Lebanon	33 min
Jul 17, 3:16 PM EDT	Areal Flood Advisory	PHI	Berks	119 min
Jul 17, 4:24 PM EDT	Special Weather Statement	PHI	Northampton	51 min
Jul 17, 4:56 PM EDT	Special Weather Statement	PHI	Philadelphia	49 min
Jul 17, 4:57 PM EDT	Special Weather Statement	PHI	Chester	33 min
Jul 17, 4:46 PM EDT	Areal Flood Advisory	PHI	Cecil, Kent	119 min
Jul 17, 4:52 PM EDT	Special Weather Statement	PHI	Cecil	53 min
Jul 17, 5:11 PM EDT	Special Weather Statement	PHI	Kent	49 min
Jul 17, 5:19 PM EDT	Special Weather Statement	PHI	Cecil	56 min
Jul 17, 6:13 PM EDT	Areal Flood Advisory	PHI	Kent, Queen Anne's	2 hr
Jul 17, 6:16 PM EDT	Special Weather Statement	PHI	Queen Anne's	44 min
Jul 17, 6:49 PM EDT	Special Weather Statement	PHI	Caroline, Queen Anne's, Talbot	56 min

Nearby

Special Weather Statements in Pennsylvania, 2017 Every special weather statement in 2017

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.