Alert archive / Maryland / Severe Thunderstorm Warnings in 2018
Severe Thunderstorm Warning 71, NWS Philadelphia/Mount Holly
NWS Philadelphia/Mount Holly issued this severe thunderstorm warning at Aug 11, 2018, 4:19 PM EDT for Cecil County, Maryland; New Castle County, Delaware; Chester County, Pennsylvania. It was in force for 29 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 11, 2018, 4:19 PM EDT (20:19 UTC)
- Expired
- Aug 11, 2018, 4:48 PM EDT
- In force
- 29 min
- Issued by
- NWS Philadelphia/Mount Holly
- Area
- Storm-based polygon
- Hail
- 0.75 in
- Wind
- 60.0 mph
Counties New Castle County, DE, Cecil County, MD, Chester County, PA
The radar
The Dover AFB radar (KDOX), 105 km from the middle of the area, began a volume at 20:19 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 12:00Z, 8.3 hours before the alert went out and 160 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
- 963 J/kg
- Mixed-layer CIN
- -38 J/kg
- Mixed-layer LCL
- 1021 m above ground
- 0-6 km bulk shear
- 23 kt
- 0-1 km storm-relative helicity
- 59 m²/s²
- 0-3 km storm-relative helicity
- 57 m²/s²
- Significant tornado parameter
- 0.0
- Supercell composite
- 1.6
The text
As transmitted.
465
WUUS51 KPHI 112019
SVRPHI
DEC003-MDC015-PAC029-112100-
/O.NEW.KPHI.SV.W.0071.180811T2019Z-180811T2100Z/
BULLETIN - IMMEDIATE BROADCAST REQUESTED
Severe Thunderstorm Warning
National Weather Service Mount Holly NJ
419 PM EDT SAT AUG 11 2018
The National Weather Service in Mount Holly NJ has issued a
* Severe Thunderstorm Warning for...
Northwestern New Castle County in northern Delaware...
Northeastern Cecil County in northeastern Maryland...
South central Chester County in southeastern Pennsylvania...
* Until 500 PM EDT.
* At 418 PM EDT, a severe thunderstorm was located over Blake, or 8
miles west of Newark, moving east at 15 mph.
HAZARD...60 mph wind gusts.
SOURCE...Radar indicated.
IMPACT...Damage to roofs, siding, trees, and power lines is
possible.
* Locations impacted include...
Newark, Elkton, Calvert, Kennett Square, Oxford, West Grove, Zion,
Blake, Barksdale, Stanton, North Star, Bear, Pike Creek, Fair Hill,
Glen Westover, Ashland, Lombard, Andora, Pleasant Hill and Cherry
Hill.
PRECAUTIONARY/PREPAREDNESS ACTIONS...
For your protection move to an interior room on the lowest floor of a
building.
In addition to damaging winds, frequent cloud to ground lightning is
occurring with this storm. Move indoors immediately. Remember, if
you can hear thunder, you are close enough to be struck by lightning.
Torrential rainfall is also occurring with this storm, and may lead
to flash flooding. Do not drive your vehicle through flooded
roadways.
&&
LAT...LON 3965 7601 3972 7605 3980 7600 3984 7570
3982 7562 3967 7563 3961 7566
TIME...MOT...LOC 2018Z 268DEG 13KT 3972 7591
HAIL...<.75IN
WIND...60MPH
$$
JRK2 follow-up statements
069
WWUS51 KPHI 112034
SVSPHI
Severe Weather Statement
National Weather Service Mount Holly NJ
434 PM EDT SAT AUG 11 2018
DEC003-MDC015-PAC029-112100-
/O.CON.KPHI.SV.W.0071.000000T0000Z-180811T2100Z/
New Castle DE-Cecil MD-Chester PA-
434 PM EDT SAT AUG 11 2018
...A SEVERE THUNDERSTORM WARNING REMAINS IN EFFECT UNTIL 500 PM EDT
FOR NORTHWESTERN NEW CASTLE...NORTHEASTERN CECIL AND SOUTH CENTRAL
CHESTER COUNTIES...
At 433 PM EDT, severe thunderstorms were located along a line
extending from Blake to Pike Creek, moving east at 15 mph.
HAZARD...60 mph wind gusts.
SOURCE...Radar indicated.
IMPACT...Damage to roofs, siding, trees, and power lines is
possible.
These severe storms will be near...
Pike Creek, Hockessin and Bear around 440 PM EDT.
Stanton and Ashland around 445 PM EDT.
Greenville around 455 PM EDT.
Newark and North Star around 500 PM EDT.
Other locations impacted by these severe thunderstorms include
Avondale, Toughkenamon and Brookside.
PRECAUTIONARY/PREPAREDNESS ACTIONS...
For your protection move to an interior room on the lowest floor of a
building.
In addition to damaging winds, frequent cloud to ground lightning is
occurring with this storm. Move indoors immediately. Remember, if
you can hear thunder, you are close enough to be struck by lightning.
Torrential rainfall is also occurring with these storms, and may
lead to flash flooding. Do not drive your vehicle through flooded
roadways.
&&
LAT...LON 3965 7597 3967 7600 3974 7598 3978 7593
3982 7587 3984 7570 3982 7562 3967 7563
3961 7566
TIME...MOT...LOC 2033Z 268DEG 14KT 3973 7589 3973 7570
HAIL...<.75IN
WIND...60MPH
$$
JRK480
WWUS51 KPHI 112048
SVSPHI
Severe Weather Statement
National Weather Service Mount Holly NJ
448 PM EDT SAT AUG 11 2018
DEC003-MDC015-PAC029-112058-
/O.CAN.KPHI.SV.W.0071.000000T0000Z-180811T2100Z/
New Castle DE-Cecil MD-Chester PA-
448 PM EDT SAT AUG 11 2018
...THE SEVERE THUNDERSTORM WARNING FOR NORTHWESTERN NEW CASTLE...
NORTHEASTERN CECIL AND SOUTH CENTRAL CHESTER COUNTIES IS CANCELLED...
The storms which prompted the warning have weakened below severe
limits, and no longer pose an immediate threat to life or property.
Therefore, the warning has been cancelled. However gusty winds and
heavy rain are still possible with these thunderstorms.
LAT...LON 3965 7597 3967 7600 3974 7598 3978 7593
3982 7587 3984 7570 3982 7562 3967 7563
3961 7566
TIME...MOT...LOC 2046Z 268DEG 13KT 3973 7582 3973 7563
$$
JRKThe office that day
Everything else NWS Philadelphia/Mount Holly issued on the same UTC day.
| Issued | Product | Office | Counties | Lasted |
|---|---|---|---|---|
| Aug 11, 3:24 AM EDT | Flash Flood Watch | PHI | Cecil, Kent, Queen Anne's | 20 hr |
| Aug 11, 4:19 PM EDT | Areal Flood Advisory | PHI | Cecil | 3 hr |
| Aug 11, 5:20 PM EDT | Areal Flood Advisory | PHI | Cecil, Kent, Queen Anne's | 4 hr |
| Aug 11, 5:24 PM EDT | Special Weather Statement | PHI | Cecil | 36 min |
| Aug 11, 6:08 PM EDT | Severe Thunderstorm Warning | PHI | Kent, Queen Anne's | 52 min |
| Aug 11, 6:12 PM EDT | Flash Flood Warning | PHI | Cecil, Kent, Queen Anne's | 3 hr |
| Aug 11, 6:45 PM EDT | Flash Flood Warning | PHI | Caroline, Queen Anne's, Talbot | 5 hr |
| Aug 11, 6:55 PM EDT | Severe Thunderstorm Warning | PHI | Caroline, Queen Anne's, Talbot | 50 min |
| Aug 11, 7:42 PM EDT | Special Weather Statement | PHI | Caroline, Queen Anne's, Talbot | 48 min |
| Aug 11, 4:26 AM EDT | Coastal Flood Advisory | PHI | Kent, New Castle, Sussex | 24 hr |
| Aug 11, 1:23 PM EDT | Severe Thunderstorm Warning | PHI | Sussex | 37 min |
| Aug 11, 2:25 AM EDT | Special Weather Statement | PHI | Berks | 65 min |
| Aug 11, 3:26 AM EDT | Special Weather Statement | PHI | Berks | 64 min |
| Aug 11, 4:17 AM EDT | Areal Flood Advisory | PHI | Berks | 4 hr |
| Aug 11, 5:19 AM EDT | Flash Flood Warning | PHI | Berks | 3 hr |
| Aug 11, 5:27 AM EDT | Areal Flood Advisory | PHI | Northampton | 4 hr |
| Aug 11, 6:06 AM EDT | Areal Flood Advisory | PHI | Bucks, Northampton | 6 hr |
| Aug 11, 6:31 AM EDT | Areal Flood Advisory | PHI | Bucks | 7 hr |
| Aug 11, 12:16 PM EDT | Special Weather Statement | PHI | Chester | 29 min |
| Aug 11, 12:48 PM EDT | Areal Flood Advisory | PHI | Chester | 3 hr |
| Aug 11, 1:20 PM EDT | Areal Flood Advisory | PHI | Chester, Montgomery | 3 hr |
| Aug 11, 1:33 PM EDT | Flash Flood Warning | PHI | Chester, Montgomery | 4 hr |
| Aug 11, 1:40 PM EDT | Flash Flood Warning | PHI | Chester | 4 hr |
| Aug 11, 1:48 PM EDT | Flash Flood Warning | PHI | Delaware, Philadelphia | 4 hr |
| Aug 11, 1:51 PM EDT | Severe Thunderstorm Warning | PHI | Bucks, Chester, Delaware, Montgomery, Philadelphia | 39 min |
| Aug 11, 2:00 PM EDT | Flash Flood Warning | PHI | Bucks, Lehigh, Northampton | 9 hr |
| Aug 11, 2:14 PM EDT | Flash Flood Warning | PHI | Bucks | 3 hr |
| Aug 11, 2:26 PM EDT | Special Weather Statement | PHI | Bucks, Philadelphia | 34 min |
| Aug 11, 2:42 PM EDT | Special Weather Statement | PHI | Bucks | 33 min |
| Aug 11, 3:06 PM EDT | Flash Flood Warning | PHI | Northampton | 4 hr |
| Aug 11, 3:50 PM EDT | Areal Flood Advisory | PHI | Berks, Montgomery | 115 min |
| Aug 11, 4:47 PM EDT | Special Weather Statement | PHI | Montgomery | 28 min |
| Aug 11, 4:52 PM EDT | Areal Flood Advisory | PHI | Carbon, Lehigh | 2 hr |
| Aug 11, 5:36 PM EDT | Areal Flood Warning | PHI | Bucks | 4 hr |
| Aug 11, 5:58 PM EDT | Areal Flood Advisory | PHI | Chester, Delaware, Montgomery, Philadelphia | 5 hr |
| Aug 11, 6:13 PM EDT | Special Weather Statement | PHI | Chester | 32 min |
Nearby
Severe Thunderstorm Warnings in Maryland, 2018Severe Thunderstorm Warnings in Delaware, 2018Severe Thunderstorm Warnings in Pennsylvania, 2018Every severe thunderstorm warning in 2018
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.