Alert archive / Pennsylvania / Special Weather Statements in 2021

Special Weather Statement, NWS Philadelphia/Mount Holly

September 15, 2021Lehigh County, Pennsylvania

NWS Philadelphia/Mount Holly issued this special weather statement at Sep 15, 2021, 7:17 PM EDT for Lehigh County, Pennsylvania. It was in force for 28 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
Sep 15, 2021, 7:17 PM EDT (23:17 UTC)
Expired
Sep 15, 2021, 7:45 PM EDT
In force
28 min
Issued by
NWS Philadelphia/Mount Holly
Hail
0.25 in
Wind
50

County Lehigh County, PA

The radar

The Philadelphia radar (KDIX), 138 km from the middle of the area, began a volume at 23:17 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

Washington/Dulle, VA (KIAD), launched 12:00Z, 11.3 hours before the alert went out and 221 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 12:00Z on 2021-09-15Temperature and dew point through the depth of the atmosphere, with the mixed-layer parcel. CAPE 13 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 12:00Z on 2021-09-15The wind through the lowest 10 kilometers. Zero to 1 km storm-relative helicity 73 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
13 J/kg
Mixed-layer CIN
-270 J/kg
Mixed-layer LCL
1457 m above ground
0-6 km bulk shear
30 kt
0-1 km storm-relative helicity
73 m²/s²
0-3 km storm-relative helicity
106 m²/s²
Significant tornado parameter
0.0
Supercell composite
0.0

Open this sounding in Storm Lab

The text

As transmitted.

040 
WWUS81 KPHI 152317
SPSPHI

Special Weather Statement
National Weather Service Mount Holly NJ
717 PM EDT Wed Sep 15 2021
 
PAZ060-061-152345-
Lehigh PA-Berks PA-
717 PM EDT Wed Sep 15 2021

...A strong thunderstorm will impact portions of northeastern Berks
and central Lehigh Counties through 745 PM EDT...

At 717 PM EDT, Doppler radar was tracking a strong thunderstorm near
Shoemakersville, or 13 miles north of Reading, moving east at 35 mph.

HAZARD...Wind gusts up to 50 mph and pea size hail.

SOURCE...Radar indicated.

IMPACT...Gusty winds could knock down tree limbs and blow around 
         unsecured objects. Minor damage to outdoor objects is 
         possible.

Locations impacted include...
Kutztown, Hamburg, Topton, Leesport, Shoemakersville, Lyons,
Lenhartsville, Ancient Oaks, Claussville, Macungie, Alburtis and
Centerport.

This includes Interstate 78 in Pennsylvania between mile markers 29
and 52.
 
PRECAUTIONARY/PREPAREDNESS ACTIONS...

If outdoors, consider seeking shelter inside a building. 

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

This storm may intensify, so be certain to monitor local radio
stations and available television stations for additional information
and possible warnings from the National Weather Service.

A Severe Thunderstorm Watch remains in effect until 1000 PM EDT for
eastern Pennsylvania.

&&

LAT...LON 4045 7599 4056 7603 4071 7566 4049 7555
TIME...MOT...LOC 2317Z 250DEG 28KT 4053 7592 

MAX HAIL SIZE...0.25 IN
MAX WIND GUST...50 MPH

$$

MPS

The office that day

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

IssuedProductOfficeCountiesLasted
Sep 15, 3:25 AM EDTSmall Craft AdvisoryPHI21 hr
Sep 15, 7:36 PM EDTSpecial Weather StatementPHIHunterdon, Morris24 min
Sep 15, 5:31 PM EDTSpecial Weather StatementPHIMonroe29 min
Sep 15, 6:29 PM EDTSpecial Weather StatementPHILebanon31 min
Sep 15, 6:48 PM EDTSpecial Weather StatementPHIBerks27 min
Sep 15, 7:08 PM EDTSevere Thunderstorm WarningPHIBerks37 min

Nearby

Special Weather Statements in Pennsylvania, 2021Every special weather statement in 2021

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.