Alert archive / Delaware / Areal Flood Advisories in 2018

Areal Flood Advisory 45, NWS Philadelphia/Mount Holly

May 12, 2018Sussex County, Delaware

NWS Philadelphia/Mount Holly issued this areal flood advisory at May 12, 2018, 10:28 PM EDT for Sussex County, Delaware. It was in force for 65 min.

The area

The counties it named.

The facts

Issued: May 12, 2018, 10:28 PM EDT (02:28 UTC)
Expired: May 12, 2018, 11:33 PM EDT
In force: 65 min
Issued by: NWS Philadelphia/Mount Holly
Area: Storm-based polygon

County Sussex County, DE

The radar

The Dover AFB radar (KDOX), 18 km from the middle of the area, began a volume at 02:27 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

Wallops Is Stn, VA (KWAL), launched 00:00Z, 2.5 hours before the alert went out and 84 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-p

Temperature in red, dew point in green, the mixed-layer parcel dashed.

Hodograph

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: 1641 J/kg
Mixed-layer CIN: -127 J/kg
Mixed-layer LCL: 1626 m above ground
0-6 km bulk shear: 30 kt
0-1 km storm-relative helicity: 159 m²/s²
0-3 km storm-relative helicity: 220 m²/s²
Significant tornado parameter: 0.0
Supercell composite: 2.1

Open this sounding in Storm Lab

What forecasters said that day

The local office's own words before this areal flood advisory went out, as it sent them, from the Iowa Environmental Mesonet's archive of National Weather Service text.

NWS Philadelphia/Mount Holly wrote its last area forecast discussion before this areal flood advisory went out at May 12, 10:20 PM EDT, 8 minutes earlier.

Area forecast discussion, May 12, 10:20 PM EDT, 8 minutes before

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Hazardous weather outlook, May 12, 10:24 PM EDT, 4 minutes before

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In the hours before

Local storm report, May 12, 9:04 PM EDT, 1 hour 24 minutes before

PRELIMINARY LOCAL STORM REPORT
NATIONAL WEATHER SERVICE MOUNT HOLLY NJ
904 PM EDT SAT MAY 12 2018

..TIME...   ...EVENT...      ...CITY LOCATION...     ...LAT.LON...
..DATE...   ....MAG....      ..COUNTY LOCATION..ST.. ...SOURCE....
            ..REMARKS..

0847 PM     HAIL             WYOMING                 39.12N  75.56W
05/12/2018  E1.25 INCH       KENT               DE   SOCIAL MEDIA

&&

EVENT NUMBER PHI1800692

DAVIS

Special weather statement, May 12, 9:07 PM EDT, 1 hour 21 minutes before

Special Weather Statement
National Weather Service Mount Holly NJ
907 PM EDT SAT MAY 12 2018

NJZ020>027-130145-
Coastal Atlantic-Cumberland-Coastal Ocean-Ocean-Atlantic-Atlantic
Coastal Cape May-Cape May-Southeastern Burlington-
907 PM EDT SAT MAY 12 2018

...A LINE OF STRONG THUNDERSTORMS WILL AFFECT SOUTHERN ATLANTIC...
SOUTHERN CUMBERLAND...SOUTHEASTERN OCEAN...CAPE MAY AND SOUTHEASTERN
BURLINGTON COUNTIES...

At 906 PM EDT, radar indicated strong thunderstorms were located
along a line extending from Barnegat to near Mays Landing to near
Fortesque. Movement was southeast at 40 mph.

Winds up to 40 mph and half inch hail are possible with these storms.

Locations impacted include...
Toms River, Vineland, Atlantic City, Millville, Ocean City,
Cumberland, Barnegat, Pleasantville, Somers Point, Brigantine,
Northfield, Absecon, Egg Harbor City, Laurel Lake, Tuckerton,
Woodbine, Sea Isle City, Estell Manor, Surf City and Port Republic.

Frequent cloud to ground lightning is occurring with this storm.
Lightning can strike 10 miles away from a thunderstorm. Seek a safe
shelter inside a building or vehicle.

A tornado watch remains in effect until 100 AM EDT for southern New
Jersey.

LAT...LON 3974 7419 3976 7410 3955 7426 3954 7440
      3956 7441 3941 7440 3949 7431 3942 7434
      3933 7468 3929 7455 3893 7497 3917 7490
      3930 7530 3952 7472 4002 7406
TIME...MOT...LOC 0106Z 314DEG 37KT 3976 7423 3948 7466 3926 7522

Local storm report, May 12, 9:46 PM EDT, 42 minutes before

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Local storm report, May 12, 10:04 PM EDT, 24 minutes before

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Local storm report, May 12, 10:08 PM EDT, 20 minutes before

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Local storm report, May 12, 10:11 PM EDT, 17 minutes before

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The office that day

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

Issued	Product	Office	Counties	Lasted
May 12, 8:00 PM EDT	Areal Flood Advisory	PHI	Atlantic, Burlington, Camden, Cumberland, Gloucester, Salem	3 hr
May 12, 8:26 PM EDT	Special Weather Statement	PHI	Atlantic, Burlington, Cape May, Cumberland	49 min
May 12, 8:37 PM EDT	Special Marine Warning	PHI		53 min
May 12, 9:07 PM EDT	Special Weather Statement	PHI	Atlantic, Cape May, Cumberland, Ocean	38 min
May 12, 9:16 PM EDT	Special Marine Warning	PHI		29 min
May 12, 9:34 PM EDT	Areal Flood Advisory	PHI	Atlantic, Cape May, Cumberland	117 min
May 12, 9:37 PM EDT	Special Marine Warning	PHI		83 min
May 12, 8:11 PM EDT	Severe Thunderstorm Warning	PHI	Kent, New Castle	49 min
May 12, 8:50 PM EDT	Flash Flood Warning	PHI	Kent, New Castle	3 hr
May 12, 8:51 PM EDT	Severe Thunderstorm Warning	PHI	Kent, Sussex	39 min
May 12, 9:14 PM EDT	Areal Flood Advisory	PHI	Kent	2 hr
May 12, 9:27 PM EDT	Severe Thunderstorm Warning	PHI	Kent, Sussex	63 min

Nearby

Areal Flood Advisories in Delaware, 2018 Every areal flood advisory 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.