Alert archive / Delaware / Severe Thunderstorm Warnings in 2009
Severe Thunderstorm Warning 167, NWS Philadelphia/Mount Holly
NWS Philadelphia/Mount Holly issued this severe thunderstorm warning at Jul 31, 2009, 4:36 PM EDT for Sussex County, Delaware. It was in force for 54 min. 1 report came from inside the area while it was in force.
The area
The outline as issued, with what was reported inside it.
The facts
- Issued
- Jul 31, 2009, 4:36 PM EDT (20:36 UTC)
- Expired
- Jul 31, 2009, 5:30 PM EDT
- In force
- 54 min
- Issued by
- NWS Philadelphia/Mount Holly
- Area
- Storm-based polygon
County Sussex County, DE
The radar
The Dover AFB radar (KDOX), 29 km from the middle of the area, began a volume at 20:39 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 was reported inside it
| Time | Report | Where | Remark |
|---|---|---|---|
| Jul 31, 4:55 PM EDT | TSTM WND DMG | Frankford, DE | TREE LIMBS REPORTED DOWN IN FRANKFORD. |
Local storm reports filed while the alert was in force, from inside its polygon or its counties.
The watch it was issued in
The SPC watch in force over the same counties when this warning went out.
| Issued | Product | Office | Lasted |
|---|---|---|---|
| Jul 31, 1:18 PM EDT | Severe Thunderstorm Watch | SPC | 7 hr |
The nearest sounding before it
Wallops Is Stn, VA (KWAL), launched 12:00Z, 8.6 hours before the alert went out and 75 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
- 969 J/kg
- Mixed-layer CIN
- -11 J/kg
- Mixed-layer LCL
- 484 m above ground
- 0-6 km bulk shear
- 33 kt
- 0-1 km storm-relative helicity
- 53 m²/s²
- 0-3 km storm-relative helicity
- 101 m²/s²
- Significant tornado parameter
- 0.3
- Supercell composite
- 2.0
The text
As transmitted, in the capitals the NWS used until 2016.
000
WUUS51 KPHI 312036
SVRPHI
DEC005-312130-
/O.NEW.KPHI.SV.W.0167.090731T2036Z-090731T2130Z/
BULLETIN - EAS ACTIVATION REQUESTED
SEVERE THUNDERSTORM WARNING
NATIONAL WEATHER SERVICE MOUNT HOLLY NJ
436 PM EDT FRI JUL 31 2009
THE NATIONAL WEATHER SERVICE IN MOUNT HOLLY NJ HAS ISSUED A
* SEVERE THUNDERSTORM WARNING FOR...
SOUTHERN SUSSEX COUNTY IN SOUTHERN DELAWARE...
* UNTIL 530 PM EDT
* AT 435 PM EDT...NATIONAL WEATHER SERVICE DOPPLER RADAR INDICATED A
SEVERE THUNDERSTORM CAPABLE OF PRODUCING NICKEL SIZE HAIL...AND
DESTRUCTIVE WINDS IN EXCESS OF 70 MPH. THIS STORM WAS LOCATED 11
MILES SOUTHWEST OF SYCAMORE...OR 8 MILES NORTH OF SALISBURY...AND
MOVING NORTHEAST AT 35 MPH.
* THE SEVERE THUNDERSTORM WILL BE NEAR...
SYCAMORE AROUND 450 PM EDT...
7 MILES NORTHWEST OF GUMBORO AROUND 455 PM EDT...
6 MILES NORTHWEST OF DAGSBORO AROUND 510 PM EDT...
9 MILES NORTHWEST OF MILLVILLE AROUND 520 PM EDT...
PRECAUTIONARY/PREPAREDNESS ACTIONS...
DOPPLER RADAR HAS INDICATED SOME WEAK ROTATION WITHIN THIS STORM.
WHILE NOT IMMEDIATELY LIKELY...A TORNADO MAY STILL DEVELOP. IF A
TORNADO IS SPOTTED...ACT QUICKLY AND MOVE TO A PLACE OF SAFETY IN A
STURDY STRUCTURE...SUCH AS A BASEMENT OR SMALL INTERIOR ROOM.
A SEVERE THUNDERSTORM WATCH REMAINS IN EFFECT UNTIL 900 PM EDT FRIDAY
EVENING FOR DELAWARE AND NORTHEASTERN MARYLAND AND NEW JERSEY AND
EASTERN PENNSYLVANIA.
&&
LAT...LON 3846 7570 3867 7571 3870 7510 3869 7506
3860 7505 3860 7504 3860 7505 3859 7504
3858 7505 3845 7505
TIME...MOT...LOC 2036Z 240DEG 31KT 3848 7561
$$
IOVINO1 follow-up statement
000
WWUS51 KPHI 312128
SVSPHI
SEVERE WEATHER STATEMENT
NATIONAL WEATHER SERVICE MOUNT HOLLY NJ
528 PM EDT FRI JUL 31 2009
DEC005-312136-
/O.EXP.KPHI.SV.W.0167.000000T0000Z-090731T2130Z/
SUSSEX DE-
528 PM EDT FRI JUL 31 2009
...THE SEVERE THUNDERSTORM WARNING FOR SOUTHERN SUSSEX COUNTY WILL
EXPIRE AT 530 PM EDT...
THE SQUALL LINE WHICH PROMPTED THE WARNING HAS MOVED EAST OF THE
AREA AND IS NO LONGER A THREAT.
A SEVERE THUNDERSTORM WATCH REMAINS IN EFFECT UNTIL 900 PM EDT FRIDAY
EVENING FOR DELAWARE AND NORTHEASTERN MARYLAND AND NEW JERSEY AND
EASTERN PENNSYLVANIA.
LAT...LON 3846 7570 3867 7571 3870 7510 3869 7506
3860 7505 3860 7504 3860 7505 3859 7504
3858 7505 3845 7505
TIME...MOT...LOC 2126Z 240DEG 31KT 3869 7514
$$
AMCThe office that day
Everything else NWS Philadelphia/Mount Holly issued on the same UTC day.
| Issued | Product | Office | Counties | Lasted |
|---|---|---|---|---|
| Jul 31, 4:03 PM EDT | Severe Thunderstorm Warning | PHI | New Castle | 57 min |
| Jul 31, 4:08 PM EDT | Flash Flood Warning | PHI | New Castle | 3 hr |
| Jul 31, 4:12 PM EDT | Severe Thunderstorm Warning | PHI | Kent, New Castle, Sussex | 73 min |
Nearby
Severe Thunderstorm Warnings in Delaware, 2009Every severe thunderstorm warning in 2009
Sources
The product and its follow-ups from the Iowa Environmental Mesonet's archive of National Weather Service and Storm Prediction Center text; local storm reports from the same archive; the sounding from the Mesonet's radiosonde archive; radar from the NEXRAD Level II archive.