Alert archive / Pennsylvania / Special Weather Statements in 2017

Special Weather Statement, NWS Philadelphia/Mount Holly

August 3, 2017Lehigh County, Northampton County, Pennsylvania

NWS Philadelphia/Mount Holly issued this special weather statement at Aug 3, 2017, 9:29 PM EDT for Lehigh County, Northampton County, Pennsylvania. It was in force for 46 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 3, 2017, 9:29 PM EDT (01:29 UTC)
Expired
Aug 3, 2017, 10:15 PM EDT
In force
46 min
Issued by
NWS Philadelphia/Mount Holly

Counties Lehigh County, PA, Northampton County, PA

The radar

The Philadelphia radar (KDIX), 121 km from the middle of the area, began a volume at 01:29 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, 1.5 hours before the alert went out and 211 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 2017-08-04Temperature and dew point through the depth of the atmosphere, with the mixed-layer parcel. CAPE 87 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 2017-08-04The wind through the lowest 10 kilometers. Zero to 1 km storm-relative helicity 45 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
87 J/kg
Mixed-layer CIN
-92 J/kg
Mixed-layer LCL
937 m above ground
0-6 km bulk shear
13 kt
0-1 km storm-relative helicity
45 m²/s²
0-3 km storm-relative helicity
43 m²/s²
Significant tornado parameter
0.0
Supercell composite
0.0

Open this sounding in Storm Lab

The text

As transmitted.

996 
WWUS81 KPHI 040129
SPSPHI

Special Weather Statement
National Weather Service Mount Holly NJ
929 PM EDT THU AUG 3 2017

NJZ007-009-PAZ055-061-062-040215-
Hunterdon-Warren-Lehigh-Monroe-Northampton-
929 PM EDT THU AUG 3 2017

...A STRONG THUNDERSTORM WILL AFFECT NORTHWESTERN HUNTERDON... 
SOUTHWESTERN WARREN...CENTRAL LEHIGH...SOUTH CENTRAL MONROE AND 
NORTHAMPTON COUNTIES...

At 928 PM EDT, a strong thunderstorm was located over Northampton, or
7 miles northwest of Allentown, moving northeast at 30 mph.

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

Locations impacted include...
Allentown, Easton, Bethlehem, Forks, Emmaus, Northampton, Wilson,
Washington, Hellertown, Nazareth, Bangor, Slatington, Pen Argyl, Wind
Gap, Bath, Belvidere, Harmony, Alpha, Walnutport and Belfast.

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

LAT...LON 4071 7495 4052 7556 4067 7574 4081 7553
      4081 7548 4084 7549 4102 7522
TIME...MOT...LOC 0128Z 224DEG 24KT 4068 7554 

$$

CMS

The office that day

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

IssuedProductOfficeCountiesLasted
Aug 3, 8:02 PM EDTSpecial Weather StatementPHIWarren43 min
Aug 3, 9:11 PM EDTAreal Flood WarningPHIBurlington4 hr
Aug 3, 9:20 PM EDTAreal Flood AdvisoryPHISussex, Warren3 hr
Aug 4, 3:41 PM EDTSmall Craft AdvisoryPHI9 hr
Aug 3, 8:01 PM EDTSpecial Weather StatementPHIBerks44 min
Aug 3, 8:11 PM EDTSpecial Weather StatementPHILehigh49 min
Aug 3, 8:29 PM EDTSevere Thunderstorm WarningPHILehigh, Northampton46 min
Aug 3, 8:35 PM EDTAreal Flood AdvisoryPHIBerks, Lehigh, Northampton4 hr
Aug 3, 8:54 PM EDTSpecial Weather StatementPHIBerks51 min
Aug 4, 1:25 PM EDTSpecial Weather StatementPHIBerks65 min
Aug 4, 2:49 PM EDTAreal Flood AdvisoryPHIBerks116 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.