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, 2:38 AM EDT for Chester County, Pennsylvania; Cecil County, Maryland; New Castle County, Delaware. It was in force for 52 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, 2:38 AM EDT (06:38 UTC)
- Expired
- Aug 5, 2017, 3:30 AM EDT
- In force
- 52 min
- Issued by
- NWS Philadelphia/Mount Holly
Counties New Castle County, DE, Cecil County, MD, Chester County, PA
The radar
The Dover AFB radar (KDOX), 102 km from the middle of the area, began a volume at 06:40 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 165 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.
794
WWUS81 KPHI 050638
SPSPHI
Special Weather Statement
National Weather Service Mount Holly NJ
238 AM EDT SAT AUG 5 2017
DEZ001-MDZ008-NJZ016-PAZ101-102-050730-
New Castle-Cecil-Salem-Western Chester-Eastern Chester-
238 AM EDT SAT AUG 5 2017
...A LINE OF HEAVY SHOWERS AND THUNDERSTORMS WILL AFFECT NORTHERN
NEW CASTLE...CECIL...NORTHWESTERN SALEM AND SOUTHWESTERN CHESTER
COUNTIES...
At 236 AM EDT, radar indicated heavy showers and thunderstorms were
located along a line extending from near Quarryville to Glen Roy to
Havre De Grace to near Perryman. Movement was northeast at 30 mph.
Winds up to 30 mph are possible with these storms.
Locations impacted include...
Wilmington, Newark, West Chester, Elkton, Calvert, Pennsville,
Coatesville, Downingtown, Elsmere, Kennett Square, New Castle,
Oxford, Parkesburg, North East, West Grove, Rising Sun, Delaware
City, Charlestown, Newport and Glen Roy.
Heavy rainfall is occurring with these 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 3974 7610 3987 7599 3995 7600 4006 7563
3991 7555 3986 7560 3983 7553 3971 7549
3972 7551 3965 7553 3970 7549 3960 7554
3966 7556 3962 7561 3956 7557 3944 7601
3952 7598 3955 7608 3960 7612
TIME...MOT...LOC 0636Z 238DEG 27KT 3989 7611 3975 7604 3954 7608 3943
7619
$$
GorseThe 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, 1:59 AM EDT | Special Weather Statement | PHI | Chester, Montgomery | 46 min |
| Aug 5, 2:41 AM EDT | Special Weather Statement | PHI | Bucks, Montgomery, Philadelphia | 49 min |
Nearby
Special Weather Statements in Pennsylvania, 2017Special Weather Statements in Maryland, 2017Special Weather Statements in Delaware, 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.