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 Apr 10, 2021, 2:35 AM EDT for Delaware County, Pennsylvania. It was in force for 40 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
- Apr 10, 2021, 2:35 AM EDT (06:35 UTC)
- Expired
- Apr 10, 2021, 3:15 AM EDT
- In force
- 40 min
- Issued by
- NWS Philadelphia/Mount Holly
County Delaware County, PA
The radar
The Philadelphia radar (KDIX), 87 km from the middle of the area, began a volume at 06:34 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 00:00Z, 6.6 hours before the alert went out and 203 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
- 0 J/kg
- Mixed-layer CIN
- No buoyant parcel
- Mixed-layer LCL
- 537 m above ground
- 0-6 km bulk shear
- 32 kt
- 0-1 km storm-relative helicity
- 161 m²/s²
- 0-3 km storm-relative helicity
- 238 m²/s²
- Significant tornado parameter
- 0.0
- Supercell composite
- 0.1
The text
As transmitted.
859 WWUS81 KPHI 100635 SPSPHI Special Weather Statement National Weather Service Mount Holly NJ 235 AM EDT Sat Apr 10 2021 PAZ070-071-102-104-100715- Eastern Montgomery-Delaware-Eastern Chester-Philadelphia- 235 AM EDT Sat Apr 10 2021 ...A STRONG THUNDERSTORM WILL AFFECT SOUTH CENTRAL MONTGOMERY...EAST CENTRAL CHESTER...WEST CENTRAL PHILADELPHIA AND CENTRAL DELAWARE COUNTIES... At 235 AM EDT, a strong thunderstorm was located over Gradyville, or near West Chester, moving northeast at 20 mph. Wind gusts up to 30 mph are possible with this storm. Locations impacted include... Philadelphia, West Chester, Norristown, West Norriton, East Norriton, Westtown, Conshohocken, Narberth, Cheyney, Morris Park, Bryn Mawr, Lima, Trout Lake, Radnor Township, Gradyville, Broomall, Newtown Square, Roxborough, Concordville and King Of Prussia. This includes the following highways... Pennsylvania Turnpike between mile markers 326 and 333. Interstate 76 in Pennsylvania between mile markers 327 and 341. Interstate 476 in Pennsylvania between mile markers 4 and 19. Torrential rainfall is also occurring with this storm, and may cause localized flooding. Do not drive your vehicle through flooded roadways. LAT...LON 3985 7552 3995 7562 4015 7533 4001 7516 TIME...MOT...LOC 0635Z 232DEG 18KT 3995 7550 $$ MPS
The office that day
Everything else NWS Philadelphia/Mount Holly issued on the same UTC day.
| Issued | Product | Office | Counties | Lasted |
|---|---|---|---|---|
| Apr 10, 3:22 AM EDT | Areal Flood Advisory | PHI | Burlington, Camden, Gloucester, Salem | 2 hr |
| Apr 10, 3:44 AM EDT | Special Weather Statement | PHI | Gloucester | 46 min |
| Apr 10, 4:42 AM EDT | Special Weather Statement | PHI | Gloucester | 48 min |
| Apr 10, 4:00 PM EDT | Small Craft Advisory | PHI | 3 days | |
| Apr 10, 1:19 AM EDT | Special Weather Statement | PHI | Chester | 56 min |
| Apr 10, 2:34 AM EDT | Special Weather Statement | PHI | Chester | 41 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.