Alert archive / Pennsylvania / Severe Thunderstorm Watches in 2016
Severe Thunderstorm Watch 447
The Storm Prediction Center issued this severe thunderstorm watch at Aug 16, 2016, 3:20 PM EDT for 5 states. It was in force for 4 hr.
The area
The outline as issued.
The facts
- Issued
- Aug 16, 2016, 3:20 PM EDT (19:20 UTC)
- Expired
- Aug 16, 2016, 6:56 PM EDT
- In force
- 4 hr
- Issued by
- the Storm Prediction Center
- Largest hail expected
- 1.5 in
- Strongest gust expected
- 60 kt
All 60 counties
New Castle County, DE, Anne Arundel County, MD, Baltimore County, MD, Carroll County, MD, Cecil County, MD, City of Baltimore, MD, Frederick County, MD, Harford County, MD, Howard County, MD, Kent County, MD, Montgomery County, MD, Prince George's County, MD, Queen Anne's County, MD, Burlington County, NJ, Camden County, NJ, Gloucester County, NJ, Hunterdon County, NJ, Mercer County, NJ, Morris County, NJ, Salem County, NJ, Somerset County, NJ, Sussex County, NJ, Warren County, NJ, Adams County, PA, Berks County, PA, Bucks County, PA, Carbon County, PA, Chester County, PA, Columbia County, PA, Cumberland County, PA, Dauphin County, PA, Delaware County, PA, Juniata County, PA, Lackawanna County, PA, Lancaster County, PA, Lebanon County, PA, Lehigh County, PA, Luzerne County, PA, Lycoming County, PA, Monroe County, PA, Montgomery County, PA, Montour County, PA, Northampton County, PA, Northumberland County, PA, Perry County, PA, Philadelphia County, PA, Pike County, PA, Schuylkill County, PA, Snyder County, PA, Sullivan County, PA, Union County, PA, Wayne County, PA, Wyoming County, PA, York County, PA, Arlington County, VA, City of Alexandria, VA, City of Fairfax, VA, City of Falls Church, VA, Fairfax County, VA, Loudoun County, VA
The radar
The Sterling radar (KLWX), 123 km from the middle of the area, began a volume at 19:23 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.
What SPC expected
The probabilities SPC published with the watch, for the watch area over its life.
- Two or more tornadoes
- 10%
- One or more EF2 to EF5 tornadoes
- 2%
- Ten or more severe wind reports
- 30%
- One or more gusts of 65 knots or more
- 10%
- Ten or more severe hail reports
- 20%
- One or more hailstones of 2 inches or more
- 5%
- Six or more combined severe hail and wind reports
- 60%
Warnings issued inside it
16 tornado, severe thunderstorm and flash flood warnings for its counties while it was in force.
| Issued | Product | Office | Counties | Lasted |
|---|---|---|---|---|
| Aug 16, 3:25 PM EDT | Severe Thunderstorm Warning | CTP | Columbia, Lycoming, Sullivan | 65 min |
| Aug 16, 3:30 PM EDT | Severe Thunderstorm Warning | CTP | Cumberland, Dauphin, Perry | 45 min |
| Aug 16, 3:44 PM EDT | Severe Thunderstorm Warning | CTP | Sullivan | 46 min |
| Aug 16, 3:55 PM EDT | Severe Thunderstorm Warning | LWX | Baltimore, Carroll | 50 min |
| Aug 16, 3:56 PM EDT | Severe Thunderstorm Warning | CTP | Dauphin, Lancaster, Lebanon, York | 64 min |
| Aug 16, 4:23 PM EDT | Severe Thunderstorm Warning | PHI | Berks, Chester, Montgomery | 52 min |
| Aug 16, 4:28 PM EDT | Severe Thunderstorm Warning | CTP | Columbia, Montour, Northumberland, Schuylkill | 62 min |
| Aug 16, 4:35 PM EDT | Severe Thunderstorm Warning | CTP | Lancaster, York | 70 min |
| Aug 16, 4:40 PM EDT | Severe Thunderstorm Warning | LWX | Fauquier, Loudoun, Prince William, Warren | 35 min |
| Aug 16, 4:44 PM EDT | Severe Thunderstorm Warning | LWX | Baltimore, Harford | 46 min |
| Aug 16, 5:04 PM EDT | Severe Thunderstorm Warning | LWX | Montgomery | 26 min |
| Aug 16, 5:14 PM EDT | Severe Thunderstorm Warning | LWX | Harford | 46 min |
| Aug 16, 5:19 PM EDT | Severe Thunderstorm Warning | PHI | Berks, Lehigh, Northampton | 41 min |
| Aug 16, 5:26 PM EDT | Severe Thunderstorm Warning | CTP | Lancaster | 34 min |
| Aug 16, 5:37 PM EDT | Severe Thunderstorm Warning | PHI | Cecil | 38 min |
| Aug 16, 5:58 PM EDT | Severe Thunderstorm Warning | LWX | Harford | 24 min |
Discussions around it
SPC mesoscale discussions over the same counties from four hours before the watch to its end.
The nearest sounding before it
Washington/Dulle, VA (KIAD), launched 12:00Z, 7.3 hours before the alert went out and 120 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
- 364 J/kg
- Mixed-layer CIN
- -175 J/kg
- Mixed-layer LCL
- 773 m above ground
- 0-6 km bulk shear
- 29 kt
- 0-1 km storm-relative helicity
- 117 m²/s²
- 0-3 km storm-relative helicity
- 98 m²/s²
- Significant tornado parameter
- 0.0
- Supercell composite
- 0.3
SPC that day
Everything else SPC issued on the same UTC day.
| Issued | Product | Office | Counties | Lasted |
|---|---|---|---|---|
| Aug 16, 4:55 PM EDT | Mesoscale Discussion | SPC | New Castle | 95 min |
| Aug 16, 1:40 PM EDT | Mesoscale Discussion | SPC | Baltimore, Carroll, Frederick, Howard, Montgomery, Prince George's and 2 more | 2 hr |
| Aug 16, 6:40 PM EDT | Mesoscale Discussion | SPC | Allegany, Garrett | 2 hr |
| Aug 16, 2:57 PM EDT | Mesoscale Discussion | SPC | Beaver, Butler, Crawford, Erie, Lawrence, Mercer and 2 more | 2 hr |
Nearby
Severe Thunderstorm Watches in Pennsylvania, 2016Severe Thunderstorm Watches in Maryland, 2016Severe Thunderstorm Watches in New Jersey, 2016Every severe thunderstorm watch in 2016
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.