Alert archive / Pennsylvania / Areal Flood Advisories in 2018

Areal Flood Advisory 54, NWS Philadelphia/Mount Holly

May 17, 20184 counties in New Jersey; 5 counties in Pennsylvania; New Castle County, Delaware

NWS Philadelphia/Mount Holly issued this areal flood advisory at May 17, 2018, 2:32 AM EDT for 4 counties in New Jersey; 5 counties in Pennsylvania; New Castle County, Delaware. It was in force for 4 hr.

The area

The counties it named.

The facts

Issued: May 17, 2018, 2:32 AM EDT (06:32 UTC)
Expired: May 17, 2018, 6:30 AM EDT
In force: 4 hr
Issued by: NWS Philadelphia/Mount Holly
Area: Storm-based polygon

Counties New Castle County, DE, Burlington County, NJ, Camden County, NJ, Gloucester County, NJ, Salem County, NJ, Bucks County, PA, Chester County, PA, Delaware County, PA, Montgomery County, PA, Philadelphia County, PA

The radar

The Philadelphia radar (KDIX), 72 km from the middle of the area, began a volume at 06:33 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 00:00Z, 6.5 hours before the alert went out and 213 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: 73 J/kg
Mixed-layer CIN: -6 J/kg
Mixed-layer LCL: 601 m above ground
0-6 km bulk shear: 24 kt
0-1 km storm-relative helicity: 38 m²/s²
0-3 km storm-relative helicity: 36 m²/s²
Significant tornado parameter: 0.0
Supercell composite: 0.0

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 17, 12:20 AM EDT, 2 hours 12 minutes earlier.

Area forecast discussion, May 17, 12:20 AM EDT, 2 hours 12 minutes before

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Hazardous weather outlook, May 16, 3:47 PM EDT, 10 hours 45 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 17, 4:05 AM EDT	Small Craft Advisory	PHI		4 days
May 17, 4:26 AM EDT	Areal Flood Advisory	PHI	Hunterdon, Mercer, Middlesex, Monmouth, Morris, Somerset	4 hr
May 17, 6:29 AM EDT	Areal Flood Advisory	PHI	Burlington, Camden, Gloucester, Salem	2 hr
May 17, 7:54 PM EDT	Areal Flood Advisory	PHI	Atlantic, Cape May	2 hr
May 17, 5:16 AM EDT	Areal Flood Warning	PHI	Chester, Montgomery	6 hr
May 17, 6:01 AM EDT	River Flood Warning	PHI	Chester	7 hr
May 17, 9:50 AM EDT	River Flood Warning	PHI	Bucks	3 hr
May 17, 10:04 AM EDT	River Flood Warning	PHI	Chester, Delaware	8 hr

Nearby

Areal Flood Advisories in Pennsylvania, 2018 Areal Flood Advisories in New Jersey, 2018 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.