Alert archive / Pennsylvania / Special Weather Statements in 2017

Special Weather Statement, NWS Philadelphia/Mount Holly

October 24, 20175 counties in Pennsylvania

NWS Philadelphia/Mount Holly issued this special weather statement at Oct 24, 2017, 8:28 AM EDT for 5 counties in Pennsylvania. It was in force for 32 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, 8:28 AM EDT (12:28 UTC)
Expired
Oct 24, 2017, 9:00 AM EDT
In force
32 min
Issued by
NWS Philadelphia/Mount Holly

Counties Bucks County, PA, Delaware County, PA, Lehigh County, PA, Montgomery County, PA, Northampton County, PA

The radar

The Philadelphia radar (KDIX), 87 km from the middle of the area, began a volume at 12:31 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

Brookhaven, NY (KOKX), launched 12:00Z, 0.5 hours before the alert went out and 222 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, Brookhaven, NY at 12:00Z on 2017-10-24Temperature and dew point through the depth of the atmosphere, with the mixed-layer parcel. CAPE 229 joules per kilogram.LCLLFCEL10008507005003002001001 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, Brookhaven, NY at 12:00Z on 2017-10-24The wind through the lowest 10 kilometers. Zero to 1 km storm-relative helicity 443 square meters per square second.19395878Sfc1 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
229 J/kg
Mixed-layer CIN
-36 J/kg
Mixed-layer LCL
611 m above ground
0-6 km bulk shear
50 kt
0-1 km storm-relative helicity
443 m²/s²
0-3 km storm-relative helicity
413 m²/s²
Significant tornado parameter
0.4
Supercell composite
4.3

Open this sounding in Storm Lab

The text

As transmitted.

181 
WWUS81 KPHI 241228
SPSPHI

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

DEZ001-PAZ060>062-070-071-101>106-241300-
New Castle-Lower Bucks-Upper Bucks-Lehigh-Eastern Montgomery-Western
Montgomery-Delaware-Western Chester-Northampton-Eastern
Chester-Berks-Philadelphia-
828 AM EDT TUE OCT 24 2017

...A LINE OF SHOWERS WILL AFFECT NORTHEASTERN NEW CASTLE... 
BUCKS...LEHIGH...MONTGOMERY...DELAWARE...NORTHERN CHESTER...EAST 
CENTRAL BERKS AND WESTERN PHILADELPHIA COUNTIES...

At 827 AM EDT, radar indicated showers were located along a line
extending from near Ancient Oaks to near Valley Forge to Wilmington.
Movement was northeast at 45 mph.

Winds up to 50 mph are possible with these showers.

Locations impacted include...
Philadelphia, Allentown, Wilmington, Easton, Bethlehem, Norristown,
Chester, Phoenixville, Lansdale, West Norriton, Forks, East Norriton,
Yeadon, Emmaus, Westtown, Northampton, Quakertown, Perkasie,
Doylestown and Wilson.

LAT...LON 4076 7518 4057 7519 4057 7510 4041 7506
      3992 7516 3985 7528 3984 7536 3977 7546
      3972 7548 3972 7552 3968 7554 3963 7562
      4007 7552 4056 7573 4082 7546 4083 7538
      4090 7524
TIME...MOT...LOC 1227Z 224DEG 38KT 4055 7563 4013 7546 3976 7554 

$$

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, 8:07 AM EDTSpecial Weather StatementPHIChester, Montgomery23 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.