Alert archive / Pennsylvania / Special Weather Statements in 2017
Special Weather Statement, NWS Philadelphia/Mount Holly
NWS Philadelphia/Mount Holly issued this special weather statement at Aug 5, 2017, 1:59 AM EDT for Chester County, Montgomery County, Pennsylvania. It was in force for 46 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 5, 2017, 1:59 AM EDT (05:59 UTC)
- Expired
- Aug 5, 2017, 2:45 AM EDT
- In force
- 46 min
- Issued by
- NWS Philadelphia/Mount Holly
Counties Chester County, PA, Montgomery County, PA
The radar
The Philadelphia radar (KDIX), 100 km from the middle of the area, began a volume at 06:00 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, 6.0 hours before the alert went out and 208 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
- 786 J/kg
- Mixed-layer CIN
- -29 J/kg
- Mixed-layer LCL
- 1447 m above ground
- 0-6 km bulk shear
- 33 kt
- 0-1 km storm-relative helicity
- 128 m²/s²
- 0-3 km storm-relative helicity
- 202 m²/s²
- Significant tornado parameter
- 0.3
- Supercell composite
- 3.7
The text
As transmitted.
882 WWUS81 KPHI 050559 SPSPHI Special Weather Statement National Weather Service Mount Holly NJ 159 AM EDT SAT AUG 5 2017 PAZ060-070-101>105-050645- Upper Bucks-Eastern Montgomery-Western Montgomery-Delaware-Western Chester-Eastern Chester-Berks- 159 AM EDT SAT AUG 5 2017 ...A LINE OF STRONG THUNDERSTORMS WILL AFFECT SOUTHEASTERN BERKS... WESTERN MONTGOMERY...WESTERN BUCKS...CENTRAL CHESTER AND NORTHERN DELAWARE COUNTIES... At 158 AM EDT, radar indicated heavy showers and some thunderstorms were located along a line extending from near Elverson to near Kennett Square. Movement was northeast at 25 mph. Winds up to 30 mph are possible with these storms. Locations impacted include... West Chester, Norristown, Pottstown, Phoenixville, West Norriton, East Norriton, Coatesville, Westtown, Downingtown, Conshohocken, Collegeville, Royersford, Trappe, Schwenksville, Elverson, Green Lane, Cheyney, Pughtown, Bryn Mawr and Marshallton. Heavy rainfall is occurring with these showers and storms, and may cause localized flooding and will result in times of significantly reduced visibilities. Do not drive your vehicle through flooded roadways. Occasional cloud to ground lightning is occurring. Lightning can strike 10 miles away from a thunderstorm. Seek a safe shelter inside a building or vehicle. LAT...LON 4039 7541 3998 7528 3984 7582 4023 7584 TIME...MOT...LOC 0558Z 233DEG 22KT 4020 7577 3989 7572 $$ Gorse
The office that day
Everything else NWS Philadelphia/Mount Holly issued on the same UTC day.
| Issued | Product | Office | Counties | Lasted |
|---|---|---|---|---|
| Aug 5, 1:42 AM EDT | Special Weather Statement | PHI | Hunterdon, Warren | 48 min |
| Aug 5, 3:32 AM EDT | Special Weather Statement | PHI | Burlington, Camden, Gloucester, Mercer, Middlesex | 58 min |
| Aug 5, 4:15 AM EDT | Special Weather Statement | PHI | Middlesex, Monmouth | 45 min |
| Aug 5, 4:42 AM EDT | Special Marine Warning | PHI | 63 min | |
| Aug 5, 3:24 PM EDT | Small Craft Advisory | PHI | 12 hr | |
| Aug 4, 11:36 PM EDT | Severe Thunderstorm Warning | PHI | Berks | 69 min |
| Aug 4, 11:49 PM EDT | Special Weather Statement | PHI | Carbon, Lehigh | 56 min |
| Aug 5, 12:10 AM EDT | Severe Thunderstorm Warning | PHI | Berks, Chester, Montgomery | 51 min |
| Aug 5, 2:38 AM EDT | Special Weather Statement | PHI | Chester | 52 min |
| Aug 5, 2:41 AM EDT | Special Weather Statement | PHI | Bucks, Montgomery, Philadelphia | 49 min |
Nearby
Special Weather Statements in Pennsylvania, 2017Every special weather statement in 2017
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.