Alert archive / Pennsylvania / Special Weather Statements in 2017

Special Weather Statement, NWS Philadelphia/Mount Holly

July 23, 2017Delaware County, Pennsylvania

NWS Philadelphia/Mount Holly issued this special weather statement at Jul 23, 2017, 5:22 PM EDT for Delaware County, Pennsylvania. It was in force for 23 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 23, 2017, 5:22 PM EDT (21:22 UTC)
Expired
Jul 23, 2017, 5:45 PM EDT
In force
23 min
Issued by
NWS Philadelphia/Mount Holly

County Delaware County, PA

The radar

The Philadelphia radar (KDIX), 100 km from the middle of the area, began a volume at 21:24 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, 9.4 hours before the alert went out and 189 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 2017-07-23Temperature and dew point through the depth of the atmosphere, with the mixed-layer parcel. CAPE 186 joules per kilogram.LCLLFCEL10008507005003002001001 km2 km3 km6 km9 km12 km15 km-30°-20°-10°10°20°30°40°
Temperature in red, dew point in green, the mixed-layer parcel dashed.
HodographHodograph, Washington/Dulle, VA at 12:00Z on 2017-07-23The wind through the lowest 10 kilometers. Zero to 1 km storm-relative helicity 19 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
186 J/kg
Mixed-layer CIN
-43 J/kg
Mixed-layer LCL
983 m above ground
0-6 km bulk shear
21 kt
0-1 km storm-relative helicity
19 m²/s²
0-3 km storm-relative helicity
31 m²/s²
Significant tornado parameter
0.0
Supercell composite
0.1

Open this sounding in Storm Lab

The text

As transmitted.

846 
WWUS81 KPHI 232122
SPSPHI

Special Weather Statement
National Weather Service Mount Holly NJ
522 PM EDT SUN JUL 23 2017

DEZ001-PAZ070-101-102-232145-
New Castle-Delaware-Western Chester-Eastern Chester-
522 PM EDT SUN JUL 23 2017

...A STRONG THUNDERSTORM WILL AFFECT NORTH CENTRAL NEW CASTLE...
SOUTHEASTERN CHESTER AND SOUTHWESTERN DELAWARE COUNTIES...

At 522 PM EDT, a strong thunderstorm was located near Westtown, or
near West Chester, moving northeast at 15 mph.

Locations impacted include...
West Chester, Westtown, Downingtown, Gradyville, Cheyney, Newtown
Square, Elam, Lionville, Marshallton, Lima, Concordville,
Lionville-Marchwood, Broomall, Paoli, Radnor Township, West Goshen,
Malvern, Chester Heights, Exton and Upper Providence Township.

These storms will contain gusty winds up to 40 mph, torrential 
downpours and occasional cloud to ground lightning.  

Locally heavy rainfall will lead to ponding of water on roadways and 
poor visibility at times this afternoon. Poor drainage flooding 
could also develop. 

Lightning can strike 10 miles away from a thunderstorm. Seek a safe 
shelter inside a building or vehicle.

LAT...LON 3980 7559 3987 7571 4008 7569 3999 7534
TIME...MOT...LOC 2122Z 204DEG 12KT 3989 7562 

$$

JRK

The office that day

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

IssuedProductOfficeCountiesLasted
Jul 22, 8:05 PM EDTSpecial Weather StatementPHIOcean25 min
Jul 22, 10:52 PM EDTAreal Flood AdvisoryPHIHunterdon, Mercer, Middlesex, Monmouth, Somerset4 hr
Jul 23, 12:01 AM EDTCoastal Flood AdvisoryPHIAtlantic, Burlington, Cape May, Cumberland, Middlesex, Monmouth and 1 more25 hr
Jul 23, 3:16 PM EDTFlash Flood WatchPHIBurlington, Camden, Gloucester, Hunterdon, Mercer, Middlesex and 6 more15 hr
Jul 23, 3:43 PM EDTSpecial Marine WarningPHI92 min
Jul 23, 4:29 PM EDTSevere Thunderstorm WarningPHICape May, Cumberland26 min
Jul 23, 4:39 PM EDTAreal Flood AdvisoryPHICape May, Cumberland, Salem4 hr
Jul 23, 4:40 PM EDTSpecial Marine WarningPHI65 min
Jul 23, 4:26 PM EDTAreal Flood AdvisoryPHIChester3 hr
Jul 23, 4:48 PM EDTAreal Flood AdvisoryPHIChester, Delaware4 hr
Jul 23, 6:08 PM EDTSpecial Weather StatementPHIDelaware37 min
Jul 23, 6:53 PM EDTFlash Flood WarningPHIChester, Delaware14 hr
Jul 23, 7:20 PM EDTFlash Flood WarningPHIBerks, Chester, Montgomery6 hr
Jul 23, 7:41 PM EDTFlash Flood WarningPHIBucks, Delaware, Montgomery, Philadelphia6 hr
Jul 22, 10:18 PM EDTSpecial Weather StatementPHICaroline, Talbot72 min
Jul 22, 11:26 PM EDTAreal Flood AdvisoryPHICaroline, Queen Anne's, Talbot4 hr
Jul 23, 2:38 PM EDTSpecial Weather StatementPHICaroline, Kent, Queen Anne's, Talbot67 min
Jul 23, 2:47 PM EDTSevere Thunderstorm WarningPHICaroline, Queen Anne's, Talbot43 min
Jul 23, 2:53 PM EDTSpecial Weather StatementPHICecil52 min
Jul 23, 3:27 PM EDTSpecial Weather StatementPHICecil33 min
Jul 23, 3:31 PM EDTSpecial Weather StatementPHIDorchester44 min
Jul 23, 3:53 PM EDTAreal Flood AdvisoryPHICecil, Kent4 hr
Jul 23, 5:40 PM EDTAreal Flood AdvisoryPHICecil4 hr
Jul 23, 5:47 PM EDTSpecial Weather StatementPHICecil28 min
Jul 23, 6:22 PM EDTSpecial Weather StatementPHICecil38 min
Jul 23, 6:26 PM EDTFlash Flood WarningPHICecil4 hr
Jul 22, 11:11 PM EDTSpecial Weather StatementPHISussex64 min
Jul 23, 4:15 PM EDTSpecial Weather StatementPHINew Castle30 min
Jul 23, 4:21 PM EDTAreal Flood AdvisoryPHIKent3 hr
Jul 23, 4:44 PM EDTSpecial Weather StatementPHINew Castle16 min

Nearby

Special Weather Statements in Pennsylvania, 2017Every 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.