Alert archive / Delaware / Areal Flood Advisories in 2018

Areal Flood Advisory 272, NWS Philadelphia/Mount Holly

September 1, 2018Sussex County, Delaware

NWS Philadelphia/Mount Holly issued this areal flood advisory at Sep 1, 2018, 4:30 AM EDT for Sussex County, Delaware. It was in force for 4 hr.

The area

The counties it named.

The facts

Issued: Sep 1, 2018, 4:30 AM EDT (08:30 UTC)
Expired: Sep 1, 2018, 8:30 AM EDT
In force: 4 hr
Issued by: NWS Philadelphia/Mount Holly
Area: Storm-based polygon

County Sussex County, DE

The nearest sounding before it

Wallops Is Stn, VA (KWAL), launched 00:00Z, 8.5 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: 2306 J/kg
Mixed-layer CIN: -1 J/kg
Mixed-layer LCL: 574 m above ground
0-6 km bulk shear: 25 kt
0-1 km storm-relative helicity: 48 m²/s²
0-3 km storm-relative helicity: 126 m²/s²
Significant tornado parameter: 0.0
Supercell composite: 6.9

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 Sep 1, 3:45 AM EDT, 45 minutes earlier.

Area forecast discussion, Sep 1, 3:45 AM EDT, 45 minutes before

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Hazardous weather outlook, Sep 1, 3:48 AM EDT, 42 minutes before

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In the hours before

Special weather statement, Aug 31, 10:41 PM EDT, 5 hours 49 minutes before

Special Weather Statement
National Weather Service Mount Holly NJ
1041 PM EDT FRI AUG 31 2018

MDZ012-015-019-010315-
Queen Anne's-Talbot-Kent-
1041 PM EDT FRI AUG 31 2018

...A STRONG THUNDERSTORM WILL AFFECT WEST CENTRAL TALBOT...
SOUTHWESTERN QUEEN ANNE'S AND SOUTHWESTERN KENT COUNTIES...

At 1040 PM EDT, a strong thunderstorm was located near Romancoke, or
near South River, moving east at 10 mph.

Winds up to 40 mph and pea size hail are possible with this storm.

Locations impacted include...
Talbot, St. Michaels, Chester, Grasonville, Stevensville,
Stevensville South and Dominion.

Torrential rainfall is also occurring with this storm, and may cause
localized flooding. Do not drive your vehicle through flooded
roadways.

LAT...LON 3904 7631 3897 7622 3900 7618 3904 7621
      3904 7617 3877 7618 3879 7631 3886 7626
      3879 7620 3879 7619 3897 7625 3891 7624
      3894 7628 3889 7629 3890 7629 3893 7631
      3896 7631 3891 7634 3884 7637 3885 7638
TIME...MOT...LOC 0240Z 271DEG 9KT 3891 7640

SFJ

Special weather statement, Aug 31, 11:10 PM EDT, 5 hours 20 minutes before

Special Weather Statement
National Weather Service Mount Holly NJ
1110 PM EDT FRI AUG 31 2018

MDZ015-019-010345-
Queen Anne's-Talbot-
1110 PM EDT FRI AUG 31 2018

...A STRONG THUNDERSTORM WILL AFFECT WEST CENTRAL TALBOT AND
SOUTHWESTERN QUEEN ANNE'S COUNTIES...

At 1110 PM EDT, a strong thunderstorm was located over Kent Point, or
7 miles southeast of South River, moving southeast at 5 mph.

Winds up to 40 mph and pea size hail are possible with this storm.

Locations impacted include...
Talbot, Romancoke and Kent Point.

Torrential rainfall is also occurring with this storm, and may cause
localized flooding. Do not drive your vehicle through flooded
roadways.

LAT...LON 3892 7637 3895 7633 3890 7628 3892 7633
      3887 7633 3886 7626 3886 7630 3882 7625
      3878 7632 3883 7630 3886 7635 3877 7633
      3881 7636 3882 7636 3875 7637
TIME...MOT...LOC 0310Z 328DEG 5KT 3885 7639

SFJ

Local storm report, Aug 31, 11:42 PM EDT, 4 hours 48 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
Sep 1, 6:07 AM EDT	Special Marine Warning	PHI		53 min
Sep 1, 6:57 AM EDT	Special Marine Warning	PHI		63 min
Sep 1, 4:05 PM EDT	Areal Flood Advisory	PHI	Cape May	3 hr
Aug 31, 8:00 PM EDT	Areal Flood Warning	PHI	Berks, Chester	4 hr
Aug 31, 8:28 PM EDT	Areal Flood Warning	PHI	Sussex	3 hr
Aug 31, 8:55 PM EDT	Areal Flood Warning	PHI	New Castle	3 hr
Sep 1, 5:36 AM EDT	Flash Flood Warning	PHI	Sussex	4 hr
Sep 1, 4:03 PM EDT	Areal Flood Advisory	PHI	Sussex	3 hr

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.