Alert archive / Pennsylvania / Areal Flood Advisories in 2018
Areal Flood Advisory 255, NWS Philadelphia/Mount Holly
NWS Philadelphia/Mount Holly issued this areal flood advisory at Aug 21, 2018, 11:18 PM EDT for Mercer County, New Jersey; 5 counties in Pennsylvania; New Castle County, Delaware. It was in force for 3 hr.
The area
The counties it named.
The facts
- Issued
- Aug 21, 2018, 11:18 PM EDT (03:18 UTC)
- Expired
- Aug 22, 2018, 2:17 AM EDT
- In force
- 3 hr
- Issued by
- NWS Philadelphia/Mount Holly
- Area
- Storm-based polygon
Counties New Castle County, DE, Mercer County, NJ, Bucks County, PA, Chester County, PA, Delaware County, PA, Montgomery County, PA, Philadelphia County, PA
The radar
The Philadelphia radar (KDIX), 76 km from the middle of the area, began a volume at 03:18 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, 3.3 hours before the alert went out and 217 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
- 509 J/kg
- Mixed-layer CIN
- -28 J/kg
- Mixed-layer LCL
- 727 m above ground
- 0-6 km bulk shear
- 41 kt
- 0-1 km storm-relative helicity
- 72 m²/s²
- 0-3 km storm-relative helicity
- 91 m²/s²
- Significant tornado parameter
- 0.2
- Supercell composite
- 3.5
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 Aug 21, 11:04 PM EDT, 14 minutes earlier.
Area forecast discussion, Aug 21, 11:04 PM EDT, 14 minutes before
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</html>Hazardous weather outlook, Aug 21, 9:51 PM EDT, 1 hour 27 minutes before
Hazardous Weather Outlook National Weather Service Mount Holly NJ 951 PM EDT Tue Aug 21 2018 DEZ001>003-MDZ008-012-015-019-020-NJZ001-007>010-012-013-015>023-027- PAZ054-055-060>062-070-071-101>106-230200- New Castle-Kent-Inland Sussex-Cecil-Kent MD-Queen Annes-Talbot- Caroline-Sussex-Warren-Morris-Hunterdon-Somerset-Middlesex- Western Monmouth-Mercer-Salem-Gloucester-Camden- Northwestern Burlington-Ocean-Cumberland-Atlantic-Cape May- Southeastern Burlington-Carbon-Monroe-Berks-Lehigh-Northampton- Delaware-Philadelphia-Western Chester-Eastern Chester- Western Montgomery-Eastern Montgomery-Upper Bucks-Lower Bucks- 951 PM EDT Tue Aug 21 2018 This Hazardous Weather Outlook is for central Delaware, northern Delaware, southern Delaware, northeast Maryland, central New Jersey, northern New Jersey, northwest New Jersey, southern New Jersey, east central Pennsylvania, northeast Pennsylvania and southeast Pennsylvania. .DAY ONE...Tonight. Showers and thunderstorms may produce locally heavy rain which could result in flooding of small streams and creeks, roadways and areas of poor drainage. .DAYS TWO THROUGH SEVEN...Wednesday through Monday. The probability for widespread hazardous weather is low. .SPOTTER INFORMATION STATEMENT... Weather spotters are encouraged to report significant weather conditions according to standard operating procedures. DEZ004-NJZ014-024>026-230200- Delaware Beaches-Eastern Monmouth-Atlantic Coastal Cape May- Coastal Atlantic-Coastal Ocean- 951 PM EDT Tue Aug 21 2018 This Hazardous Weather Outlook is for southern Delaware, central New Jersey and southern New Jersey. .DAY ONE...Tonight. Showers and thunderstorms may produce locally heavy rain which could result in flooding of roadways and areas of poor drainage. .DAYS TWO THROUGH SEVEN...Wednesday through Monday. There is a moderate risk for the development of dangerous rip currents. .SPOTTER INFORMATION STATEMENT... Weather spotters are encouraged to report significant weather conditions according to standard operating procedures. ANZ430-431-450>455-230200- Delaware Bay waters north of East Point NJ to Slaughter Beach DE- Delaware Bay waters south of East Point NJ to Slaughter Beach DE- Coastal waters from Sandy Hook to Manasquan Inlet NJ out 20 nm- Coastal waters from Manasquan Inlet to Little Egg Inlet NJ out 20 nm- Coastal waters from Little Egg Inlet to Great Egg Inlet NJ out 20 nm- Coastal waters from Great Egg Inlet to Cape May NJ out 20 nm- Coastal waters from Cape May NJ to Cape Henlopen DE out 20 nm- Coastal waters from Cape Henlopen to Fenwick Island DE out 20 nm- 951 PM EDT Tue Aug 21 2018 This Hazardous Weather Outlook is for Atlantic coastal waters and Delaware Bay Waters. .DAY ONE...Tonight. The probability for widespread hazardous weather is low. .DAYS TWO THROUGH SEVEN...Wednesday through Monday. The probability for widespread hazardous weather is low. .SPOTTER INFORMATION STATEMENT... Weather spotters are encouraged to report significant weather conditions according to standard operating procedures.
In the hours before
Special weather statement, Aug 21, 7:07 PM EDT, 4 hours 11 minutes before
Special Weather Statement
National Weather Service Mount Holly NJ
707 PM EDT TUE AUG 21 2018
DEZ003-004-MDZ015-019-020-220000-
Inland Sussex-Delaware Beaches-Queen Anne's-Talbot-Caroline-
707 PM EDT TUE AUG 21 2018
...A LINE OF STRONG THUNDERSTORMS WITH TORRENTIAL DOWNPOURS WILL
AFFECT SOUTHERN SUSSEX...TALBOT...SOUTHWESTERN QUEEN ANNE'S AND
SOUTHERN CAROLINE COUNTIES EARLY THIS EVENING...
At 701 PM EDT, radar indicated a line of strong thunderstorms
extending from 20 miles southwest of Easton to Salisbury University
to 10 miles south of Bethany Beach. Movement was north at 25 mph.
These storms will be near...
Delmar and Oxford around 725 PM EDT.
Trappe around 730 PM EDT.
Hambleton, Bethany Beach and Windyhill around 735 PM EDT.
Easton, Laurel, Sharptown and Tanyard around 745 PM EDT.
Sycamore and Copperville around 750 PM EDT.
Seaford around 755 PM EDT.
Georgetown, Federalsburg, Cordova, Matthews and Griffin around 800
PM EDT.
Winds of 30 to 40 mph are possible with these storms.
Torrential rainfall is also occurring with these storms, and may
cause localized flooding, especially in poor drainage areas. Do not
drive your vehicle through flooded roadways.
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.
LAT...LON 3846 7569 3869 7577 3868 7593 3857 7604
3868 7621 3876 7622 3871 7628 3878 7629
3877 7632 3867 7634 3876 7638 3886 7626
3881 7621 3878 7621 3889 7619 3889 7618
3887 7619 3889 7583 3860 7522 3845 7505
TIME...MOT...LOC 2301Z 200DEG 21KT 3853 7618 3831 7587 3834 7562
JRKSpecial weather statement, Aug 21, 8:05 PM EDT, 3 hours 13 minutes before
Special Weather Statement
National Weather Service Mount Holly NJ
805 PM EDT TUE AUG 21 2018
DEZ001>004-MDZ008-012-015-019-020-220045-
Inland Sussex-Kent-New Castle-Delaware Beaches-Queen
Anne's-Talbot-Cecil-Kent-Caroline-
805 PM EDT TUE AUG 21 2018
...A LINE OF STRONG THUNDERSTORMS WILL AFFECT SUSSEX...SOUTHWESTERN
NEW CASTLE...KENT...NORTHEASTERN TALBOT...QUEEN ANNE'S...CAROLINE...
KENT AND CECIL COUNTIES...
At 803 PM EDT, radar indicated strong thunderstorms were located
along a line extending from near Millers Island to Georgetown to
Bethany Beach. Movement was northeast at 25 mph.
These storms will be near...
Ellendale around 815 PM EDT.
Milton around 820 PM EDT.
Newtown around 825 PM EDT.
Milford and Lewes around 830 PM EDT.
Other locations impacted by these storms include Barclay, Chesapeake
City, Wyoming, Long Neck, Kent Acres, South Bethany, Kingstown,
Templeville, Ocean View and Highland Acres.
Winds up to 35 mph are possible with these storms.
Torrential rainfall is also occurring with these storms, and may
cause localized flooding in poor drainage areas. Do not drive your
vehicle through flooded roadways.
Cloud to ground lightning is also occurring with this storm.
Lightning can strike 10 miles away from a thunderstorm. Seek a safe
shelter inside a building or vehicle.
LAT...LON 3881 7614 3898 7627 3897 7622 3900 7617
3917 7628 3932 7618 3942 7600 3952 7598
3972 7623 3972 7607 3926 7541 3907 7541
3891 7531 3878 7512 3880 7509 3869 7514
3862 7507 3859 7521 3861 7506 3845 7505
TIME...MOT...LOC 0003Z 208DEG 25KT 3923 7635 3870 7539 3847 7506
JRKLocal storm report, Aug 21, 10:18 PM EDT, 1 hour before
PRELIMINARY LOCAL STORM REPORT
NATIONAL WEATHER SERVICE MOUNT HOLLY NJ
1018 PM EDT TUE AUG 21 2018
..TIME... ...EVENT... ...CITY LOCATION... ...LAT.LON...
..DATE... ....MAG.... ..COUNTY LOCATION..ST.. ...SOURCE....
..REMARKS..
1002 PM MARINE TSTM WIND 2 NNE STRATHMERE 39.22N 74.64W
08/21/2018 M39 MPH CAPE MAY NJ WEATHERFLOW
OCEAN CITY SOUTH BEACH SENSOR.
&&
EVENT NUMBER PHI1801412
CMSLocal storm report, Aug 21, 10:48 PM EDT, 30 minutes before
PRELIMINARY LOCAL STORM REPORT
NATIONAL WEATHER SERVICE MOUNT HOLLY NJ
1048 PM EDT TUE AUG 21 2018
..TIME... ...EVENT... ...CITY LOCATION... ...LAT.LON...
..DATE... ....MAG.... ..COUNTY LOCATION..ST.. ...SOURCE....
..REMARKS..
1032 PM FLOOD WYOMISSING 40.33N 75.96W
08/21/2018 BERKS PA SOCIAL MEDIA
REPORTS OF BASEMENT FLOODING IN WYOMISSING.
&&
EVENT NUMBER PHI1801413
CMSLocal storm report, Aug 21, 11:13 PM EDT, 5 minutes before
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</html>Local storm report, Aug 21, 11:18 PM EDT, 0 minutes before
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</html>The office that day
Everything else NWS Philadelphia/Mount Holly issued on the same UTC day.
| Issued | Product | Office | Counties | Lasted |
|---|---|---|---|---|
| Aug 21, 9:34 PM EDT | Special Marine Warning | PHI | 116 min | |
| Aug 21, 10:46 PM EDT | Areal Flood Advisory | PHI | Hunterdon, Warren | 4 hr |
| Aug 21, 11:47 PM EDT | Areal Flood Advisory | PHI | Hunterdon, Morris, Somerset, Warren | 4 hr |
| Aug 22, 1:12 AM EDT | Areal Flood Advisory | PHI | Sussex | 5 hr |
| Aug 22, 1:54 AM EDT | Areal Flood Advisory | PHI | Atlantic, Burlington, Camden, Cumberland, Gloucester, Ocean and 1 more | 4 hr |
| Aug 21, 8:53 PM EDT | Areal Flood Advisory | PHI | Berks, Chester, Montgomery | 5 hr |
| Aug 21, 10:16 PM EDT | Flash Flood Warning | PHI | Berks, Chester, Montgomery | 7 hr |
| Aug 21, 11:08 PM EDT | Flash Flood Warning | PHI | Bucks, Lehigh, Northampton | 4 hr |
| Aug 22, 1:14 AM EDT | Areal Flood Advisory | PHI | Monroe | 4 hr |
| Aug 22, 2:54 AM EDT | Areal Flood Warning | PHI | Bucks, Lehigh, Northampton | 8 hr |
| Aug 22, 4:36 AM EDT | River Flood Warning | PHI | Montgomery | 6 hr |
| Aug 22, 5:14 AM EDT | Areal Flood Warning | PHI | Berks, Chester, Montgomery | 4 hr |
| Aug 22, 10:04 AM EDT | River Flood Warning | PHI | Chester, Montgomery, Philadelphia | 5 hr |
| Aug 21, 8:05 PM EDT | Special Weather Statement | PHI | Kent, Sussex | 40 min |
| Aug 22, 12:32 AM EDT | Areal Flood Advisory | PHI | Kent, New Castle | 3 hr |
Nearby
Areal Flood Advisories in Pennsylvania, 2018Areal Flood Advisories in New Jersey, 2018Areal Flood Advisories in Delaware, 2018Every 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.