Alert archive / Pennsylvania / Special Weather Statements in 2021

Special Weather Statement, NWS Philadelphia/Mount Holly

August 9, 2021Montgomery County, Pennsylvania

NWS Philadelphia/Mount Holly issued this special weather statement at Aug 9, 2021, 6:49 PM EDT for Montgomery County, Pennsylvania. It was in force for 26 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 9, 2021, 6:49 PM EDT (22:49 UTC)
Expired: Aug 9, 2021, 7:15 PM EDT
In force: 26 min
Issued by: NWS Philadelphia/Mount Holly
Hail: 0.25 in
Wind: 40

County Montgomery County, PA

The radar

The Philadelphia radar (KDIX), 112 km from the middle of the area, began a volume at 22:51 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, 10.8 hours before the alert went out and 218 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: 568 J/kg
Mixed-layer CIN: -78 J/kg
Mixed-layer LCL: 916 m above ground
0-6 km bulk shear: 13 kt
0-1 km storm-relative helicity: -13 m²/s²
0-3 km storm-relative helicity: -21 m²/s²
Significant tornado parameter: 0.0
Supercell composite: 0.0

Open this sounding in Storm Lab

The text

As transmitted.

658 
WWUS81 KPHI 092249
SPSPHI

Special Weather Statement
National Weather Service Mount Holly NJ
649 PM EDT Mon Aug 9 2021
 
PAZ060-103-092315-
Western Montgomery PA-Berks PA-
649 PM EDT Mon Aug 9 2021

...A strong thunderstorm will impact portions of east central Berks
and northwestern Montgomery Counties through 715 PM EDT...

At 649 PM EDT, Doppler radar was tracking a strong thunderstorm over
Gilbertsville, or 15 miles east of Reading, moving northeast at 5
mph.

HAZARD...Winds in excess of 40 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...
Pottstown, Bally, Bechtelsville, Green Lane, Gilbertsville, Stowe,
Boyertown, Sanatoga, Pottsgrove, Halfway House, South Pottstown and
Kenilworth.

PRECAUTIONARY/PREPAREDNESS ACTIONS...

If outdoors, consider seeking shelter inside a building. 

&&

LAT...LON 4045 7565 4032 7542 4023 7563 4029 7573
TIME...MOT...LOC 2249Z 224DEG 6KT 4033 7563 

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

$$

SFJ

The office that day

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

Issued	Product	Office	Counties	Lasted
Aug 9, 3:43 PM EDT	Excessive Heat Watch	PHI	Burlington, Camden, Gloucester, Hunterdon, Mercer, Middlesex and 4 more	12 hr
Aug 9, 4:36 PM EDT	Areal Flood Advisory	PHI	Atlantic, Cape May, Cumberland, Gloucester, Salem	104 min
Aug 9, 4:45 PM EDT	Special Weather Statement	PHI	Atlantic	30 min
Aug 9, 5:40 PM EDT	Areal Flood Advisory	PHI	Camden, Gloucester	82 min
Aug 9, 6:10 PM EDT	Special Weather Statement	PHI	Burlington	35 min
Aug 9, 6:37 PM EDT	Special Weather Statement	PHI	Mercer	38 min
Aug 9, 5:12 PM EDT	Areal Flood Advisory	PHI	Chester, Delaware	85 min
Aug 9, 5:34 PM EDT	Special Weather Statement	PHI	Philadelphia	26 min
Aug 9, 6:24 PM EDT	Special Weather Statement	PHI	Lehigh	36 min
Aug 9, 6:29 PM EDT	Areal Flood Advisory	PHI	Berks, Montgomery	70 min
Aug 9, 7:14 PM EDT	Special Weather Statement	PHI	Carbon	31 min
Aug 9, 2:10 PM EDT	Special Weather Statement	PHI	Sussex	50 min
Aug 9, 2:41 PM EDT	Areal Flood Advisory	PHI	Kent, New Castle, Sussex	3 hr
Aug 9, 3:01 PM EDT	Flash Flood Warning	PHI	Kent, Sussex	2 hr
Aug 9, 4:35 PM EDT	Severe Thunderstorm Warning	PHI	Kent	40 min
Aug 9, 4:59 PM EDT	Flash Flood Warning	PHI	Kent	79 min
Aug 9, 5:12 PM EDT	Severe Thunderstorm Warning	PHI	Kent	20 min

Nearby

Special Weather Statements in Pennsylvania, 2021 Every 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.