Alert archive / Pennsylvania / Special Weather Statements in 2018

Special Weather Statement, NWS Philadelphia/Mount Holly

August 17, 2018Lehigh County, Pennsylvania

NWS Philadelphia/Mount Holly issued this special weather statement at Aug 17, 2018, 2:21 PM EDT for Lehigh County, Pennsylvania. It was in force for 24 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 17, 2018, 2:21 PM EDT (18:21 UTC)
Expired: Aug 17, 2018, 2:45 PM EDT
In force: 24 min
Issued by: NWS Philadelphia/Mount Holly

County Lehigh County, PA

The radar

The Philadelphia radar (KDIX), 105 km from the middle of the area, began a volume at 18:24 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, 6.4 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-p

Temperature in red, dew point in green, the mixed-layer parcel dashed.

Hodograph

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.

985 
WWUS81 KPHI 171821
SPSPHI

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

PAZ060-061-103-105-171845-
Upper Bucks-Lehigh-Western Montgomery-Berks-
221 PM EDT FRI AUG 17 2018

...A STRONG THUNDERSTORM WILL AFFECT EAST CENTRAL BERKS...
NORTHWESTERN MONTGOMERY...SOUTHEASTERN LEHIGH AND NORTHWESTERN BUCKS
COUNTIES...

At 220 PM EDT, a strong thunderstorm was located over Bally, or 13
miles south of Allentown, moving east at 30 mph.

Winds up to 40 mph and brief heavy downpours are possible with this 
storm.

This storm will be near...
  East Greenville, Geryville and Zionsville around 230 PM EDT.
  Quakertown around 245 PM EDT.

Other locations impacted by this storm include Pennsburg,
Richlandtown, Coopersburg, Trumbauersville and Red Hill.

Cloud to ground lightning may also occur with this storm.
Lightning can strike 10 miles away from a thunderstorm. Seek a safe
shelter inside a building or vehicle.

LAT...LON 4052 7545 4056 7538 4051 7532 4042 7530
      4036 7536 4035 7566 4042 7567
TIME...MOT...LOC 1820Z 251DEG 24KT 4041 7557 

$$

JRK

The office that day

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

Issued	Product	Office	Counties	Lasted
Aug 17, 3:37 PM EDT	Special Weather Statement	PHI	Hunterdon	38 min
Aug 17, 3:42 PM EDT	Special Weather Statement	PHI	Warren	48 min
Aug 17, 5:46 PM EDT	Special Weather Statement	PHI	Morris	14 min
Aug 17, 5:59 PM EDT	Severe Thunderstorm Warning	PHI	Warren	31 min
Aug 17, 6:02 PM EDT	Special Weather Statement	PHI	Morris	13 min
Aug 17, 6:22 PM EDT	Severe Thunderstorm Warning	PHI	Sussex, Warren	38 min
Aug 17, 6:59 PM EDT	Special Weather Statement	PHI	Sussex	31 min
Aug 17, 7:28 PM EDT	Special Weather Statement	PHI	Sussex	17 min
Aug 17, 7:42 PM EDT	Special Weather Statement	PHI	Hunterdon, Warren	33 min
Aug 17, 4:29 PM EDT	Special Weather Statement	PHI	Berks	46 min
Aug 17, 5:07 PM EDT	Special Weather Statement	PHI	Berks, Lehigh	53 min
Aug 17, 5:12 PM EDT	Special Weather Statement	PHI	Berks	33 min
Aug 17, 5:36 PM EDT	Special Weather Statement	PHI	Lehigh, Northampton	39 min
Aug 17, 6:00 PM EDT	Special Weather Statement	PHI	Carbon	30 min
Aug 17, 6:18 PM EDT	Special Weather Statement	PHI	Berks	27 min
Aug 17, 6:19 PM EDT	Severe Thunderstorm Warning	PHI	Carbon, Monroe	41 min
Aug 17, 6:23 PM EDT	Severe Thunderstorm Warning	PHI	Berks, Lehigh	52 min
Aug 17, 6:40 PM EDT	Flash Flood Warning	PHI	Berks	2 hr
Aug 17, 7:09 PM EDT	Severe Thunderstorm Warning	PHI	Berks, Bucks, Carbon, Chester, Lehigh, Monroe and 2 more	51 min
Aug 17, 7:15 PM EDT	Special Weather Statement	PHI	Pike	15 min
Aug 17, 7:34 PM EDT	Special Weather Statement	PHI	Carbon	26 min
Aug 17, 7:39 PM EDT	Special Weather Statement	PHI	Monroe	51 min

Nearby

Special Weather Statements in Pennsylvania, 2018 Every 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; the sounding from the Mesonet's radiosonde archive; radar from the NEXRAD Level II archive.