Alert archive / Pennsylvania / Special Weather Statements in 2021

Special Weather Statement, NWS Philadelphia/Mount Holly

September 8, 2021Lehigh County, Northampton County, Pennsylvania

NWS Philadelphia/Mount Holly issued this special weather statement at Sep 8, 2021, 9:46 PM EDT for Lehigh County, Northampton County, Pennsylvania. It was in force for 44 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 8, 2021, 9:46 PM EDT (01:46 UTC)
Expired
Sep 8, 2021, 10:30 PM EDT
In force
44 min
Issued by
NWS Philadelphia/Mount Holly
Hail
0.25 in
Wind
40

Counties Lehigh County, PA, Northampton County, PA

The radar

The Philadelphia radar (KDIX), 125 km from the middle of the area, began a volume at 01:49 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, 1.8 hours before the alert went out and 216 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 2021-09-09Temperature and dew point through the depth of the atmosphere, with the mixed-layer parcel. CAPE 619 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 2021-09-09The wind through the lowest 10 kilometers. Zero to 1 km storm-relative helicity 211 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
619 J/kg
Mixed-layer CIN
-36 J/kg
Mixed-layer LCL
807 m above ground
0-6 km bulk shear
33 kt
0-1 km storm-relative helicity
211 m²/s²
0-3 km storm-relative helicity
225 m²/s²
Significant tornado parameter
0.5
Supercell composite
3.4

Open this sounding in Storm Lab

The text

As transmitted.

286 
WWUS81 KPHI 090146
SPSPHI

Special Weather Statement
National Weather Service Mount Holly NJ
946 PM EDT Wed Sep 8 2021
 
PAZ055-061-062-090230-
Lehigh PA-Monroe PA-Northampton PA-
946 PM EDT Wed Sep 8 2021

...Strong thunderstorms will impact portions of central Lehigh, south
central Monroe and Northampton Counties through 1030 PM EDT...

At 946 PM EDT, Doppler radar was tracking strong thunderstorms along
a line extending from near Bath to near Claussville. Movement was
northeast at 20 mph.

HAZARD...Wind gusts up to 45 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...
Allentown, Bethlehem, Northampton, Nazareth, Bangor, Slatington, Pen
Argyl, Wind Gap, Bath, Walnutport, Belfast, Tatamy, East Bangor,
Steuben, Neffs, Coffeetown, Berlinsville, Emerald, Claussville and
Danielsville.

This includes the following highways...
 Northeast Extension between mile markers 57 and 69.
 Interstate 78 in Pennsylvania between mile markers 45 and 53.

PRECAUTIONARY/PREPAREDNESS ACTIONS...

If outdoors, consider seeking shelter inside a building. 

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

A Severe Thunderstorm Watch remains in effect until midnight EDT for
northwestern New Jersey...and eastern and northeastern Pennsylvania.

&&

LAT...LON 4091 7509 4077 7515 4078 7517 4075 7520
      4054 7566 4054 7568 4062 7580 4069 7574
      4079 7558 4081 7553 4081 7548 4083 7548
      4090 7531
TIME...MOT...LOC 0146Z 244DEG 19KT 4077 7539 4059 7572 

MAX HAIL SIZE...0.25 IN
MAX WIND GUST...40 MPH

$$

Staarmann

The office that day

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

IssuedProductOfficeCountiesLasted
Sep 8, 9:16 PM EDTAreal Flood AdvisoryPHIWarren3 hr
Sep 8, 9:16 PM EDTSpecial Weather StatementPHISussex, Warren29 min
Sep 8, 9:43 PM EDTSpecial Weather StatementPHISussex, Warren47 min
Sep 8, 10:42 PM EDTFlash Flood WarningPHIWarren6 hr
Sep 8, 10:56 PM EDTSpecial Weather StatementPHIWarren34 min
Sep 8, 11:27 PM EDTSevere Thunderstorm WarningPHIHunterdon, Warren48 min
Sep 8, 11:30 PM EDTAreal Flood AdvisoryPHIMorris, Sussex4 hr
Sep 9, 12:07 AM EDTSpecial Weather StatementPHIHunterdon, Somerset, Warren23 min
Sep 9, 12:18 AM EDTSpecial Marine WarningPHI57 min
Sep 9, 12:30 AM EDTSpecial Weather StatementPHIMorris30 min
Sep 9, 12:41 AM EDTSpecial Marine WarningPHI52 min
Sep 9, 2:17 AM EDTSpecial Weather StatementPHIOcean28 min
Sep 9, 2:46 AM EDTSpecial Weather StatementPHIAtlantic29 min
Sep 9, 3:14 AM EDTSpecial Weather StatementPHIAtlantic31 min
Sep 9, 3:30 AM EDTAreal Flood AdvisoryPHIAtlantic, Burlington, Cape May, Cumberland112 min
Sep 9, 4:28 AM EDTAreal Flood WarningPHIWarren4 hr
Sep 8, 8:47 PM EDTSpecial Weather StatementPHINorthampton28 min
Sep 8, 9:12 PM EDTSpecial Weather StatementPHILehigh48 min
Sep 8, 9:38 PM EDTSpecial Weather StatementPHIBerks52 min
Sep 8, 9:48 PM EDTFlash Flood WarningPHILehigh, Northampton7 hr
Sep 8, 9:59 PM EDTAreal Flood AdvisoryPHIBerks3 hr
Sep 8, 10:11 PM EDTSevere Thunderstorm WarningPHIBerks49 min
Sep 8, 10:23 PM EDTTornado WarningPHIBerks22 min
Sep 8, 10:27 PM EDTSpecial Weather StatementPHINorthampton33 min
Sep 8, 10:47 PM EDTAreal Flood AdvisoryPHICarbon, Monroe3 hr
Sep 8, 10:47 PM EDTSevere Thunderstorm WarningPHIBerks, Lehigh, Montgomery, Northampton58 min
Sep 8, 11:35 PM EDTSpecial Weather StatementPHIChester, Delaware, Montgomery40 min
Sep 9, 12:08 AM EDTSpecial Weather StatementPHIBucks, Delaware, Montgomery, Philadelphia37 min
Sep 9, 4:26 AM EDTAreal Flood WarningPHILehigh, Northampton3 hr
Sep 9, 12:58 AM EDTSpecial Weather StatementPHINew Castle32 min
Sep 9, 1:12 AM EDTAreal Flood AdvisoryPHINew Castle62 min
Sep 9, 5:37 AM EDTAreal Flood AdvisoryPHIKent, New Castle, Sussex3 hr

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.