Alert archive / Pennsylvania / Special Weather Statements in 2018

Special Weather Statement, NWS Philadelphia/Mount Holly

August 17, 2018Lehigh County, Northampton County, Pennsylvania

NWS Philadelphia/Mount Holly issued this special weather statement at Aug 17, 2018, 5:36 PM EDT for Lehigh County, Northampton County, Pennsylvania. It was in force for 39 min. 4 reports came from inside the area while it was in force.

The area

The outline as issued, with what was reported inside it.

The facts

Issued
Aug 17, 2018, 5:36 PM EDT (21:36 UTC)
Expired
Aug 17, 2018, 6:15 PM EDT
In force
39 min
Issued by
NWS Philadelphia/Mount Holly

Counties Lehigh County, PA, Northampton County, PA

The radar

The Philadelphia radar (KDIX), 123 km from the middle of the area, began a volume at 21:36 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.

What was reported inside it

TimeReportWhereRemark
Aug 17, 6:00 PM EDTTSTM WND DMGBath, PATWO TREES DOWNED.
Aug 17, 6:00 PM EDTTSTM WND DMGMoore Twp, PASEVERAL REPORTS OF DOWNED TREES AND POWER LINES IN MOORE TWP...ALLEN TWP...AND CHAPMAN. TIME ESTIMATED FROM RADAR.
Aug 17, 6:00 PM EDTTSTM WND GST 62Bath, PA
Aug 17, 6:03 PM EDTTSTM WND DMGBushkill Twp, PAMULTIPLE REPORTS OF TREES AND WIRES DOWN IN BUSHKILL TOWNSHIP

Local storm reports filed while the alert was in force, from inside its polygon or its counties.

The nearest sounding before it

Brookhaven, NY (KOKX), launched 12:00Z, 9.6 hours before the alert went out and 223 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 2018-08-17Temperature and dew point through the depth of the atmosphere, with the mixed-layer parcel. CAPE 321 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 12:00Z on 2018-08-17The wind through the lowest 10 kilometers. Zero to 1 km storm-relative helicity 38 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
321 J/kg
Mixed-layer CIN
-56 J/kg
Mixed-layer LCL
1245 m above ground
0-6 km bulk shear
20 kt
0-1 km storm-relative helicity
38 m²/s²
0-3 km storm-relative helicity
65 m²/s²
Significant tornado parameter
0.0
Supercell composite
0.3

Open this sounding in Storm Lab

The text

As transmitted.

346 
WWUS81 KPHI 172136
SPSPHI

Special Weather Statement
National Weather Service Mount Holly NJ
536 PM EDT FRI AUG 17 2018

PAZ054-055-061-062-172215-
Lehigh-Monroe-Northampton-Carbon-
536 PM EDT FRI AUG 17 2018

...A STRONG THUNDERSTORM WILL AFFECT CENTRAL LEHIGH...SOUTHEASTERN
CARBON...SOUTH CENTRAL MONROE AND WEST CENTRAL NORTHAMPTON
COUNTIES...

At 536 PM EDT, a strong thunderstorm was located over Claussville, or
7 miles west of Allentown, moving northeast at 30 mph.

Winds up to 50 mph and pea size hail are possible with this storm.

Locations impacted include...
Allentown, Bethlehem, Northampton, Nazareth, Slatington, Bath,
Walnutport, Belfast, Tatamy, Steuben, Kunkletown, Neffs, Coffeetown,
Rossland, Berlinsville, Emerald, Claussville, Danielsville,
Beersville and Schnecksville.

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

A severe thunderstorm watch remains in effect until 1100 PM EDT for
eastern and northeastern Pennsylvania.

LAT...LON 4053 7555 4065 7574 4092 7545 4077 7522
TIME...MOT...LOC 2136Z 223DEG 24KT 4063 7562 

$$

CMS

The office that day

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

IssuedProductOfficeCountiesLasted
Aug 17, 3:37 PM EDTSpecial Weather StatementPHIHunterdon38 min
Aug 17, 3:42 PM EDTSpecial Weather StatementPHIWarren48 min
Aug 17, 5:46 PM EDTSpecial Weather StatementPHIMorris14 min
Aug 17, 5:59 PM EDTSevere Thunderstorm WarningPHIWarren31 min
Aug 17, 6:02 PM EDTSpecial Weather StatementPHIMorris13 min
Aug 17, 6:22 PM EDTSevere Thunderstorm WarningPHISussex, Warren38 min
Aug 17, 6:59 PM EDTSpecial Weather StatementPHISussex31 min
Aug 17, 7:28 PM EDTSpecial Weather StatementPHISussex17 min
Aug 17, 7:42 PM EDTSpecial Weather StatementPHIHunterdon, Warren33 min
Aug 17, 2:21 PM EDTSpecial Weather StatementPHILehigh24 min
Aug 17, 4:29 PM EDTSpecial Weather StatementPHIBerks46 min
Aug 17, 5:07 PM EDTSpecial Weather StatementPHIBerks, Lehigh53 min
Aug 17, 5:12 PM EDTSpecial Weather StatementPHIBerks33 min
Aug 17, 6:00 PM EDTSpecial Weather StatementPHICarbon30 min
Aug 17, 6:18 PM EDTSpecial Weather StatementPHIBerks27 min
Aug 17, 6:19 PM EDTSevere Thunderstorm WarningPHICarbon, Monroe41 min
Aug 17, 6:23 PM EDTSevere Thunderstorm WarningPHIBerks, Lehigh52 min
Aug 17, 6:40 PM EDTFlash Flood WarningPHIBerks2 hr
Aug 17, 7:09 PM EDTSevere Thunderstorm WarningPHIBerks, Bucks, Carbon, Chester, Lehigh, Monroe and 2 more51 min
Aug 17, 7:15 PM EDTSpecial Weather StatementPHIPike15 min
Aug 17, 7:34 PM EDTSpecial Weather StatementPHICarbon26 min
Aug 17, 7:39 PM EDTSpecial Weather StatementPHIMonroe51 min

Nearby

Special Weather Statements in Pennsylvania, 2018Every special weather statement in 2018

Sources

The product and its follow-ups from the Iowa Environmental Mesonet's archive of National Weather Service and Storm Prediction Center text; local storm reports from the same archive; the sounding from the Mesonet's radiosonde archive; radar from the NEXRAD Level II archive.