Alert archive / Pennsylvania / Special Weather Statements in 2021
Special Weather Statement, NWS Philadelphia/Mount Holly
NWS Philadelphia/Mount Holly issued this special weather statement at Aug 23, 2021, 4:41 PM EDT for Montgomery County, Pennsylvania. It was in force for 34 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 23, 2021, 4:41 PM EDT (20:41 UTC)
- Expired
- Aug 23, 2021, 5:15 PM EDT
- In force
- 34 min
- Issued by
- NWS Philadelphia/Mount Holly
- Hail
- 0.00 in
- Wind
- 40
County Montgomery County, PA
The radar
The Philadelphia radar (KDIX), 102 km from the middle of the area, began a volume at 20:41 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, 8.7 hours before the alert went out and 207 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.
- Mixed-layer CAPE
- 5 J/kg
- Mixed-layer CIN
- -84 J/kg
- Mixed-layer LCL
- 1259 m above ground
- 0-6 km bulk shear
- 22 kt
- 0-1 km storm-relative helicity
- 90 m²/s²
- 0-3 km storm-relative helicity
- 46 m²/s²
- Significant tornado parameter
- 0.0
- Supercell composite
- 0.0
The text
As transmitted.
656
WWUS81 KPHI 232041
SPSPHI
Special Weather Statement
National Weather Service Mount Holly NJ
441 PM EDT Mon Aug 23 2021
PAZ101>104-232115-
Eastern Montgomery PA-Western Montgomery PA-Western Chester PA-
Eastern Chester PA-
441 PM EDT Mon Aug 23 2021
...A strong thunderstorm will impact portions of southwestern
Montgomery and northeastern Chester Counties through 515 PM EDT...
At 441 PM EDT, Doppler radar was tracking a strong thunderstorm over
Royersford, or 17 miles north of West Chester, moving southeast at 15
mph.
HAZARD...Wind gusts up to 40 mph.
SOURCE...Radar indicated.
IMPACT...Gusty winds could knock down tree limbs and blow around
unsecured objects.
Locations impacted include...
West Chester, Norristown, Pottstown, Phoenixville, West Norriton,
East Norriton, Collegeville, Royersford, Trappe, Pughtown, Valley
Forge, Paoli, Chester Springs, King Of Prussia, Cedarville, Plymouth
Meeting, Lionville-Marchwood, West Goshen, Stowe and Bridgeport.
This includes the following highways...
Pennsylvania Turnpike between mile markers 314 and 333.
Interstate 76 in Pennsylvania between mile markers 327 and 329.
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.
Frequent cloud to ground lightning is occurring with this storm.
Lightning can strike 10 miles away from a thunderstorm. Seek a safe
shelter inside a building or vehicle.
&&
LAT...LON 4024 7570 4031 7558 4011 7529 3995 7559
TIME...MOT...LOC 2041Z 334DEG 14KT 4020 7555
MAX HAIL SIZE...0.00 IN
MAX WIND GUST...40 MPH
$$
GorseThe office that day
Everything else NWS Philadelphia/Mount Holly issued on the same UTC day.
| Issued | Product | Office | Counties | Lasted |
|---|---|---|---|---|
| Aug 22, 8:11 PM EDT | Areal Flood Advisory | PHI | Warren | 6 hr |
| Aug 22, 8:47 PM EDT | Flash Flood Warning | PHI | Sussex, Warren | 6 hr |
| Aug 22, 11:27 PM EDT | Areal Flood Warning | PHI | Middlesex | 29 hr |
| Aug 23, 2:09 AM EDT | River Flood Warning | PHI | Morris, Passaic | 17 hr |
| Aug 23, 3:25 AM EDT | Areal Flood Warning | PHI | Morris | 8 hr |
| Aug 23, 4:10 AM EDT | River Flood Warning | PHI | Morris | 41 hr |
| Aug 23, 5:07 AM EDT | Areal Flood Warning | PHI | Warren | 21 hr |
| Aug 23, 5:22 AM EDT | Areal Flood Warning | PHI | Somerset | 9 hr |
| Aug 23, 5:44 AM EDT | Areal Flood Warning | PHI | Hunterdon | 7 hr |
| Aug 23, 7:20 AM EDT | River Flood Warning | PHI | Hunterdon, Somerset | 7 hr |
| Aug 23, 7:47 AM EDT | River Flood Warning | PHI | Morris, Passaic | 13 hr |
| Aug 23, 8:36 AM EDT | Areal Flood Warning | PHI | Somerset | 9 hr |
| Aug 23, 8:42 AM EDT | River Flood Warning | PHI | Middlesex, Somerset | 21 hr |
| Aug 23, 11:22 AM EDT | River Flood Warning | PHI | Middlesex, Somerset | 16 hr |
| Aug 23, 11:32 AM EDT | River Flood Warning | PHI | Essex, Morris, Passaic | 5 days |
| Aug 23, 11:58 AM EDT | River Flood Warning | PHI | Somerset | 15 hr |
| Aug 23, 12:19 PM EDT | River Flood Warning | PHI | Burlington | 33 hr |
| Aug 23, 12:51 PM EDT | Coastal Flood Statement | PHI | Ocean | 3 hr |
| Aug 23, 2:26 PM EDT | Areal Flood Warning | PHI | Sussex | 14 hr |
| Aug 23, 2:26 PM EDT | Special Weather Statement | PHI | Ocean | 49 min |
| Aug 23, 3:12 PM EDT | Special Weather Statement | PHI | Ocean | 33 min |
| Aug 23, 3:15 PM EDT | Severe Thunderstorm Warning | PHI | Ocean | 45 min |
| Aug 23, 3:18 PM EDT | Special Marine Warning | PHI | 57 min | |
| Aug 23, 3:38 PM EDT | River Flood Warning | PHI | Essex, Morris, Passaic | 48 hr |
| Aug 23, 4:47 PM EDT | Special Weather Statement | PHI | Atlantic | 28 min |
| Aug 23, 4:50 PM EDT | Special Marine Warning | PHI | 55 min | |
| Aug 23, 5:13 PM EDT | Special Weather Statement | PHI | Camden | 32 min |
| Aug 23, 5:39 PM EDT | Special Marine Warning | PHI | 33 min | |
| Aug 23, 6:46 PM EDT | Special Marine Warning | PHI | 64 min | |
| Aug 22, 10:34 PM EDT | Areal Flood Advisory | PHI | Carbon, Lehigh, Northampton | 3 hr |
| Aug 22, 10:53 PM EDT | Flash Flood Warning | PHI | Carbon, Lehigh, Monroe, Montgomery, Northampton | 4 hr |
| Aug 22, 11:42 PM EDT | Areal Flood Advisory | PHI | Berks | 3 hr |
| Aug 23, 12:32 AM EDT | River Flood Warning | PHI | Monroe | 10 hr |
| Aug 23, 12:55 AM EDT | River Flood Warning | PHI | Monroe | 10 hr |
| Aug 23, 2:36 AM EDT | Areal Flood Warning | PHI | Carbon, Monroe | 21 hr |
| Aug 23, 3:50 AM EDT | River Flood Warning | PHI | Carbon | 3 hr |
| Aug 23, 3:50 AM EDT | River Flood Warning | PHI | Lehigh, Northampton | 11 hr |
| Aug 23, 8:28 AM EDT | Areal Flood Warning | PHI | Lehigh | 7 hr |
| Aug 23, 7:14 PM EDT | Severe Thunderstorm Warning | PHI | Kent, New Castle | 31 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.