Alert archive / Pennsylvania / Special Weather Statements in 2017

Special Weather Statement, NWS Philadelphia/Mount Holly

August 5, 2017Hunterdon County, Warren County, New Jersey; Bucks County, Montgomery County, Northampton County, Pennsylvania

NWS Philadelphia/Mount Holly issued this special weather statement at Aug 5, 2017, 1:42 AM EDT for Hunterdon County, Warren County, New Jersey; Bucks County, Montgomery County, Northampton County, Pennsylvania. It was in force for 48 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
Aug 5, 2017, 1:42 AM EDT (05:42 UTC)
Expired
Aug 5, 2017, 2:30 AM EDT
In force
48 min
Issued by
NWS Philadelphia/Mount Holly

Counties Hunterdon County, NJ, Warren County, NJ, Bucks County, PA, Montgomery County, PA, Northampton County, PA

The radar

The Philadelphia radar (KDIX), 91 km from the middle of the area, began a volume at 05:45 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 00:00Z, 5.7 hours before the alert went out and 178 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 00:00Z on 2017-08-05Temperature and dew point through the depth of the atmosphere, with the mixed-layer parcel. CAPE 425 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, Brookhaven, NY at 00:00Z on 2017-08-05The wind through the lowest 10 kilometers. Zero to 1 km storm-relative helicity 40 square meters per square second.1939Sfc1 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
425 J/kg
Mixed-layer CIN
-21 J/kg
Mixed-layer LCL
695 m above ground
0-6 km bulk shear
13 kt
0-1 km storm-relative helicity
40 m²/s²
0-3 km storm-relative helicity
38 m²/s²
Significant tornado parameter
0.0
Supercell composite
0.0

Open this sounding in Storm Lab

The text

As transmitted.

580 
WWUS81 KPHI 050542
SPSPHI

Special Weather Statement
National Weather Service Mount Holly NJ
142 AM EDT SAT AUG 5 2017

NJZ007-009-010-PAZ061-062-103>106-050630-
Hunterdon-Somerset-Warren-Lower Bucks-Upper Bucks-Lehigh-Eastern
Montgomery-Western Montgomery-Northampton-
142 AM EDT SAT AUG 5 2017

...A LINE OF HEAVY SHOWERS AND THUNDERSTORMS WILL AFFECT 
HUNTERDON...WARREN... SOUTHWESTERN SOMERSET... CENTRAL 
MONTGOMERY...EAST CENTRAL LEHIGH...BUCKS AND CENTRAL NORTHAMPTON 
COUNTIES...

At 138 AM EDT, radar indicated heavy showers and thunderstorms were 
located along a line extending from Steuben to near Lansdale. 
Movement was northeast at 40 mph.

Local winds up to 30 mph are possible with these storms.

Locations impacted include...
Easton, Bethlehem, Lansdale, Forks, East Norriton, Quakertown,
Perkasie, Doylestown, Byram, Wilson, Souderton, Bedminster,
Washington, Blairstown, Hellertown, Nazareth, Flemington, Chalfont,
Tinicum and High Bridge.

Heavy rainfall is occurring with these storms, and may cause 
localized flooding and will result in times of significantly reduced 
visibilities. Do not drive your vehicle through flooded roadways.

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

LAT...LON 4104 7491 4081 7485 4079 7489 4074 7483
      4042 7474 4042 7480 4039 7481 4015 7540
      4071 7541
TIME...MOT...LOC 0538Z 223DEG 36KT 4070 7534 4022 7533 

$$

Gorse

The office that day

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

IssuedProductOfficeCountiesLasted
Aug 5, 3:32 AM EDTSpecial Weather StatementPHIBurlington, Camden, Gloucester, Mercer, Middlesex58 min
Aug 5, 4:15 AM EDTSpecial Weather StatementPHIMiddlesex, Monmouth45 min
Aug 5, 4:42 AM EDTSpecial Marine WarningPHI63 min
Aug 5, 3:24 PM EDTSmall Craft AdvisoryPHI12 hr
Aug 4, 11:36 PM EDTSevere Thunderstorm WarningPHIBerks69 min
Aug 4, 11:49 PM EDTSpecial Weather StatementPHICarbon, Lehigh56 min
Aug 5, 12:10 AM EDTSevere Thunderstorm WarningPHIBerks, Chester, Montgomery51 min
Aug 5, 1:59 AM EDTSpecial Weather StatementPHIChester, Montgomery46 min
Aug 5, 2:38 AM EDTSpecial Weather StatementPHIChester52 min
Aug 5, 2:41 AM EDTSpecial Weather StatementPHIBucks, Montgomery, Philadelphia49 min

Nearby

Special Weather Statements in Pennsylvania, 2017Special Weather Statements in New Jersey, 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.