Alert archive / Pennsylvania / Special Weather Statements in 2017

Special Weather Statement, NWS Philadelphia/Mount Holly

October 24, 2017Chester County, Montgomery County, Pennsylvania

NWS Philadelphia/Mount Holly issued this special weather statement at Oct 24, 2017, 8:07 AM EDT for Chester County, Montgomery 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
Oct 24, 2017, 8:07 AM EDT (12:07 UTC)
Expired
Oct 24, 2017, 8:30 AM EDT
In force
23 min
Issued by
NWS Philadelphia/Mount Holly

Counties Chester County, PA, Montgomery County, PA

The radar

The Philadelphia radar (KDIX), 106 km from the middle of the area, began a volume at 12:08 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, 0.1 hours before the alert went out and 208 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 2017-10-24Temperature and dew point through the depth of the atmosphere, with the mixed-layer parcel. CAPE 0 joules per kilogram.LCL10008507005003002001001 km2 km3 km6 km9 km12 km15 km-30°-20°-10°0°10°20°30°40°
Temperature in red, dew point in green, the mixed-layer parcel dashed.
HodographHodograph, Washington/Dulle, VA at 12:00Z on 2017-10-24The wind through the lowest 10 kilometers. Zero to 1 km storm-relative helicity 20 square meters per square second.1939587897Sfc1 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
0 J/kg
Mixed-layer CIN
No buoyant parcel
Mixed-layer LCL
955 m above ground
0-6 km bulk shear
57 kt
0-1 km storm-relative helicity
20 m²/s²
0-3 km storm-relative helicity
121 m²/s²
Significant tornado parameter
0.0
Supercell composite
0.0

Open this sounding in Storm Lab

The text

As transmitted.

192 
WWUS81 KPHI 241207
SPSPHI

Special Weather Statement
National Weather Service Mount Holly NJ
807 AM EDT TUE OCT 24 2017

DEZ001-PAZ060-070-101>104-241230-
New Castle-Eastern Montgomery-Western Montgomery-Delaware-Western
Chester-Eastern Chester-Berks-
807 AM EDT TUE OCT 24 2017

...A SHOWER WILL AFFECT NORTH CENTRAL NEW CASTLE...MONTGOMERY... 
WESTERN DELAWARE...CHESTER AND SOUTHEASTERN BERKS COUNTIES...

At 805 AM EDT, a shower was located over Kennett Square, or 8 miles
south of West Chester, moving northeast at 50 mph.

Winds up to 50 mph are possible with this shower.

Locations impacted include...
Wilmington, West Chester, Norristown, Pottstown, Phoenixville,
Lansdale, West Norriton, East Norriton, Westtown, Downingtown,
Conshohocken, Souderton, Ambler, Elsmere, Kennett Square,
Collegeville, Royersford, Trappe, Hatfield and East Greenville.

LAT...LON 4053 7576 4045 7553 4023 7517 3972 7559
      3980 7581
TIME...MOT...LOC 1205Z 204DEG 43KT 3985 7566 

$$

CMS

The office that day

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

IssuedProductOfficeCountiesLasted
Oct 24, 2:42 AM EDTGale WarningPHI16 hr
Oct 24, 6:50 AM EDTSpecial Weather StatementPHICumberland40 min
Oct 24, 7:32 AM EDTSpecial Weather StatementPHIBurlington, Camden, Gloucester28 min
Oct 24, 8:00 AM EDTSpecial Weather StatementPHIHunterdon, Mercer, Middlesex, Somerset30 min
Oct 24, 8:33 AM EDTWind AdvisoryPHISussex2 hr
Oct 24, 8:58 AM EDTSpecial Weather StatementPHIWarren32 min
Oct 24, 9:27 AM EDTSpecial Weather StatementPHIWarren33 min
Oct 24, 9:59 AM EDTSpecial Weather StatementPHIGloucester31 min
Oct 24, 10:00 AM EDTSpecial Weather StatementPHISussex, Warren30 min
Oct 24, 10:30 AM EDTSpecial Weather StatementPHIBurlington, Camden, Hunterdon30 min
Oct 24, 10:51 AM EDTSpecial Weather StatementPHIHunterdon, Morris, Somerset, Sussex, Warren39 min
Oct 24, 11:03 AM EDTSpecial Weather StatementPHIAtlantic, Burlington27 min
Oct 24, 11:11 AM EDTSpecial Weather StatementPHIMercer, Middlesex, Somerset34 min
Oct 24, 11:26 AM EDTSpecial Weather StatementPHIMorris, Somerset34 min
Oct 24, 11:31 AM EDTSpecial Weather StatementPHIAtlantic, Burlington, Ocean29 min
Oct 24, 12:03 PM EDTSpecial Weather StatementPHIMiddlesex, Morris, Sussex27 min
Oct 24, 12:28 PM EDTSpecial Weather StatementPHIMorris32 min
Oct 24, 1:04 PM EDTSpecial Weather StatementPHIMonmouth26 min
Oct 24, 2:16 PM EDTSmall Craft AdvisoryPHI13 hr
Oct 24, 5:08 PM EDTSpecial Marine WarningPHI67 min
Oct 24, 5:37 PM EDTSpecial Marine WarningPHI53 min
Oct 24, 5:41 PM EDTSpecial Weather StatementPHIAtlantic34 min
Oct 24, 5:53 PM EDTSpecial Marine WarningPHI67 min
Oct 24, 6:01 PM EDTAreal Flood AdvisoryPHIAtlantic, Burlington, Cape May, Ocean4 hr
Oct 24, 6:13 PM EDTSpecial Weather StatementPHIOcean32 min
Oct 24, 8:28 AM EDTSpecial Weather StatementPHIBucks, Delaware, Lehigh, Montgomery, Northampton32 min
Oct 24, 8:52 AM EDTSpecial Weather StatementPHIMonroe23 min
Oct 24, 5:54 AM EDTCoastal Flood AdvisoryPHICecil, Kent, Queen Anne's, Talbot6 hr

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.