Alert archive / Pennsylvania / Special Weather Statements in 2017

Special Weather Statement, NWS Philadelphia/Mount Holly

August 19, 2017Carbon County, Lehigh County, Montgomery County, Pennsylvania

NWS Philadelphia/Mount Holly issued this special weather statement at Aug 19, 2017, 8:34 PM EDT for Carbon County, Lehigh County, Montgomery County, Pennsylvania. It was in force for 56 min. 2 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 19, 2017, 8:34 PM EDT (00:34 UTC)
Expired
Aug 19, 2017, 9:30 PM EDT
In force
56 min
Issued by
NWS Philadelphia/Mount Holly

Counties Carbon County, PA, Lehigh County, PA, Montgomery County, PA

The radar

The Philadelphia radar (KDIX), 129 km from the middle of the area, began a volume at 00:34 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 19, 9:03 PM EDTTSTM WND DMGAmity Twp, PATREES AND WIRES BLOWN DOWN. TIME ESITMATED FROM RADAR.
Aug 19, 9:17 PM EDTTSTM WND GST 46S Allentown, PA

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

The nearest sounding before it

Washington/Dulle, VA (KIAD), launched 00:00Z, 0.6 hours before the alert went out and 229 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 00:00Z on 2017-08-20Temperature and dew point through the depth of the atmosphere, with the mixed-layer parcel. CAPE 675 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, Washington/Dulle, VA at 00:00Z on 2017-08-20The wind through the lowest 10 kilometers. Zero to 1 km storm-relative helicity 98 square meters per square second.1939587897117Sfc1 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
675 J/kg
Mixed-layer CIN
-14 J/kg
Mixed-layer LCL
1697 m above ground
0-6 km bulk shear
40 kt
0-1 km storm-relative helicity
98 m²/s²
0-3 km storm-relative helicity
97 m²/s²
Significant tornado parameter
0.1
Supercell composite
2.8

Open this sounding in Storm Lab

The text

As transmitted.

982 
WWUS81 KPHI 200034
SPSPHI

Special Weather Statement
National Weather Service Mount Holly NJ
834 PM EDT SAT AUG 19 2017

PAZ054-060-061-101-103-200130-
Lehigh-Western Montgomery-Western Chester-Berks-Carbon-
834 PM EDT SAT AUG 19 2017

...SHOWERS AND THUNDERSTORMS WILL AFFECT EASTERN BERKS... 
NORTHWESTERN CHESTER...UPPER MONTGOMERY...LEHIGH AND CARBON 
COUNTIES...

At 830 PM EDT, showers and thunderstorms were moving across 
Schuylkill, western Berks and Lancaster Counties.

While the thunderstorms are forecast to weaken, they may continue to 
produce wind gusts to 35 mph in eastern Berks, northwestern Chester, 
upper Montgomery, Lehigh and Carbon Counties between 900 and 1000 PM.

Locations impacted include...
Allentown, Lehighton, Pottstown, Phoenixville, Coatesville, Emmaus, 
Downingtown, Souderton, Palmerton, Collegeville, Oxford, Jim Thorpe, 
Royersford, Slatington, Parkesburg, Trappe, Nesquehoning and East 
Greenville.

LAT...LON 4099 7550 4095 7557 4082 7548 4076 7561
      4054 7533 4042 7548 4028 7524 3992 7584
      3975 7592 3972 7613 3987 7599 4011 7594
      4019 7579 4058 7573 4068 7589 4074 7576
      4091 7599 4101 7573 4109 7577 4113 7567
TIME...MOT...LOC 0027Z 270DEG 41KT 4043 7610 

$$

Iovino

The office that day

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

IssuedProductOfficeCountiesLasted
Aug 19, 9:35 PM EDTSpecial Weather StatementPHIGloucester, Hunterdon25 min
Aug 19, 9:45 PM EDTSpecial Weather StatementPHIMorris, Sussex, Warren60 min
Aug 19, 10:16 PM EDTSpecial Marine WarningPHI89 min
Aug 19, 8:01 PM EDTSevere Thunderstorm WarningPHIBerks59 min
Aug 19, 9:00 PM EDTSevere Thunderstorm WarningPHIBerks, Bucks, Carbon, Lehigh, Monroe, Montgomery and 1 more60 min
Aug 19, 9:29 PM EDTSpecial Weather StatementPHIMonroe31 min
Aug 19, 10:02 PM EDTSpecial Weather StatementPHIKent, Queen Anne's28 min
Aug 19, 10:29 PM EDTSpecial Weather StatementPHIKent31 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; local storm reports from the same archive; the sounding from the Mesonet's radiosonde archive; radar from the NEXRAD Level II archive.