Alert archive / Maryland / Severe Thunderstorm Warnings in 2018

Severe Thunderstorm Warning 102, NWS Philadelphia/Mount Holly

September 26, 2018Cecil County, Maryland; New Castle County, Delaware; Chester County, Pennsylvania

NWS Philadelphia/Mount Holly issued this severe thunderstorm warning at Sep 26, 2018, 7:53 PM EDT for Cecil County, Maryland; New Castle County, Delaware; Chester County, Pennsylvania. 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
Sep 26, 2018, 7:53 PM EDT (23:53 UTC)
Expired
Sep 26, 2018, 8:45 PM EDT
In force
52 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 watch it was issued in

The SPC watch in force over the same counties when this warning went out.

IssuedProductOfficeLasted
Sep 26, 5:02 PM EDTSevere Thunderstorm WatchSPC4 hr

The nearest sounding before it

Washington/Dulle, VA (KIAD), launched 12:00Z, 11.9 hours before the alert went out and 147 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.

Skew-T log-pSkew-T log-p diagram, Washington/Dulle, VA at 12:00Z on 2018-09-26Temperature and dew point through the depth of the atmosphere, with the mixed-layer parcel. CAPE 6 joules per kilogram.LCLLFCEL10008507005003002001001 km2 km3 km6 km9 km12 km15 km-30°-20°-10°10°20°30°40°
Temperature in red, dew point in green, the mixed-layer parcel dashed.
HodographHodograph, Washington/Dulle, VA at 12:00Z on 2018-09-26The wind through the lowest 10 kilometers. Zero to 1 km storm-relative helicity 99 square meters per square second.193958Sfc1 km3 km6 km9 kmRMLM
The wind turning with height, colored by layer: ground to 1 km, 1 to 3 km, 3 to 6 km, 6 to 10 km.
Mixed-layer CAPE
6 J/kg
Mixed-layer CIN
-201 J/kg
Mixed-layer LCL
948 m above ground
0-6 km bulk shear
20 kt
0-1 km storm-relative helicity
99 m²/s²
0-3 km storm-relative helicity
111 m²/s²
Significant tornado parameter
0.0
Supercell composite
0.1

Open this sounding in Storm Lab

The text

As transmitted.

636 
WUUS51 KPHI 262353
SVRPHI
DEC003-MDC015-PAC029-270045-
/O.NEW.KPHI.SV.W.0102.180926T2353Z-180927T0045Z/

BULLETIN - IMMEDIATE BROADCAST REQUESTED
Severe Thunderstorm Warning
National Weather Service Mount Holly NJ
753 PM EDT WED SEP 26 2018

The National Weather Service in Mount Holly NJ has issued a

* Severe Thunderstorm Warning for...
  Northwestern New Castle County in northern Delaware...
  Northern Cecil County in northeastern Maryland...
  Southwestern Chester County in southeastern Pennsylvania...

* Until 845 PM EDT.

* At 752 PM EDT, a severe thunderstorm was located over Calvert, or
  10 miles northwest of Elkton, moving east at 25 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, Havre De Grace, Calvert, Kennett Square, Oxford,
  North East, West Grove, Rising Sun, Charlestown, Glen Roy, Zion,
  Blake, Barksdale, North Star, Glasgow, Bear, West Nottingham,
  Brantwood and Mount Vernon.

PRECAUTIONARY/PREPAREDNESS ACTIONS...

For your protection move to an interior room on the lowest floor of a
building.

To report severe weather, contact your nearest law enforcement
agency. They will send your report to the National Weather Service
office in Mount Holly NJ.

In addition to large hail and 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 occurring with this storm, and may lead to
flash flooding. Do not drive your vehicle through flooded roadways.

&&

LAT...LON 3975 7609 3976 7606 3981 7603 3983 7604
      3983 7602 3985 7602 3984 7561 3949 7572
      3954 7601 3955 7603 3955 7609 3961 7613
TIME...MOT...LOC 2352Z 273DEG 21KT 3970 7598 

HAIL...<.75IN
WIND...60MPH
 
$$

MPS
2 follow-up statements
173 
WWUS51 KPHI 270020
SVSPHI

Severe Weather Statement
National Weather Service Mount Holly NJ
820 PM EDT WED SEP 26 2018

DEC003-MDC015-PAC029-270045-
/O.CON.KPHI.SV.W.0102.000000T0000Z-180927T0045Z/
New Castle DE-Cecil MD-Chester PA-
820 PM EDT WED SEP 26 2018

...A SEVERE THUNDERSTORM WARNING REMAINS IN EFFECT UNTIL 845 PM EDT
FOR NORTHWESTERN NEW CASTLE...NORTHEASTERN CECIL AND SOUTH CENTRAL
CHESTER COUNTIES...

At 819 PM EDT, a severe thunderstorm was located over North Star, or
near Newark, moving east at 25 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, Kennett Square, West Grove, Barksdale, North Star,
Glasgow, Andora, Cherry Hill, Ladenberg, Pike Creek, Kemblesville,
Fair Hill, Glen Westover, Hockessin, Ashland, Appleton, Bear,
Avondale and Toughkenamon.

PRECAUTIONARY/PREPAREDNESS ACTIONS...

For your protection move to an interior room on the lowest floor of a
building.

To report severe weather contact your nearest law enforcement agency.
They will send your report to the National Weather Service office in
Mount Holly NJ.

In addition to large hail and 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 occurring with this storm, and may lead to
flash flooding. Do not drive your vehicle through flooded roadways.

&&

LAT...LON 3984 7561 3958 7570 3968 7591 3985 7586
TIME...MOT...LOC 0019Z 262DEG 23KT 3975 7574 

HAIL...<.75IN
WIND...60MPH
 
$$

MPS
631 
WWUS51 KPHI 270036
SVSPHI

Severe Weather Statement
National Weather Service Mount Holly NJ
836 PM EDT WED SEP 26 2018

DEC003-MDC015-PAC029-270046-
/O.EXP.KPHI.SV.W.0102.000000T0000Z-180927T0045Z/
New Castle DE-Cecil MD-Chester PA-
836 PM EDT WED SEP 26 2018

...THE SEVERE THUNDERSTORM WARNING FOR NORTHWESTERN NEW CASTLE...
NORTHEASTERN CECIL AND SOUTH CENTRAL CHESTER COUNTIES WILL EXPIRE AT
845 PM EDT...
        
The storm which prompted the warning has weakened below severe
limits, and has exited the warned area. Therefore, the warning will
be allowed to expire.

A severe thunderstorm watch remains in effect until 1100 PM EDT for
northern Delaware...northeastern Maryland...and southeastern
Pennsylvania.

To report severe weather, contact your nearest law enforcement
agency. They will relay your report to the National Weather Service
in Mount Holly NJ.

LAT...LON 3984 7561 3958 7570 3968 7591 3985 7586
TIME...MOT...LOC 0036Z 273DEG 21KT 3974 7561 

$$

MPS

The office that day

Everything else NWS Philadelphia/Mount Holly issued on the same UTC day.

IssuedProductOfficeCountiesLasted
Sep 26, 7:06 PM EDTSevere Thunderstorm WarningPHICecil, Kent54 min
Sep 26, 7:16 PM EDTSevere Thunderstorm WarningPHICaroline, Cecil, Kent, Queen Anne's, Talbot43 min
Sep 26, 7:31 PM EDTAreal Flood AdvisoryPHICecil106 min
Sep 25, 9:11 PM EDTAreal Flood WarningPHIPhiladelphia3 hr
Sep 26, 6:15 PM EDTSpecial Weather StatementPHINorthampton30 min
Sep 26, 6:37 PM EDTSpecial Weather StatementPHIChester53 min
Sep 26, 6:41 PM EDTAreal Flood AdvisoryPHICarbon, Lehigh, Monroe, Northampton3 hr

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.