Alert archive / New Jersey / Flash Flood Watches in 2021
Flash Flood Watch 8, NWS Philadelphia/Mount Holly
NWS Philadelphia/Mount Holly issued this flash flood watch at Aug 26, 2021, 3:30 PM EDT for 14 counties in New Jersey; 8 counties in Pennsylvania; New Castle County, Delaware. It took effect at Aug 27, 2021, 2:00 PM EDT. It was in force for 26 hr.
The area
The counties it named.
The facts
- Issued
- Aug 26, 2021, 3:30 PM EDT (19:30 UTC)
- In effect from
- Aug 27, 2021, 2:00 PM EDT
- Expired
- Aug 28, 2021, 3:39 PM EDT
- In force
- 26 hr
- Issued by
- NWS Philadelphia/Mount Holly
- Flood severity
- None
All 23 counties
New Castle County, DE, Atlantic County, NJ, Burlington County, NJ, Camden County, NJ, Cumberland County, NJ, Gloucester County, NJ, Hunterdon County, NJ, Mercer County, NJ, Middlesex County, NJ, Monmouth County, NJ, Morris County, NJ, Ocean County, NJ, Salem County, NJ, Somerset County, NJ, Warren County, NJ, Berks County, PA, Bucks County, PA, Chester County, PA, Delaware County, PA, Lehigh County, PA, Montgomery County, PA, Northampton County, PA, Philadelphia County, PA
The radar
The Philadelphia radar (KDIX), 57 km from the middle of the area, began a volume at 19:30 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
Brookhaven, NY (KOKX), launched 12:00Z, 7.5 hours before the alert went out and 200 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
- 844 J/kg
- Mixed-layer CIN
- -55 J/kg
- Mixed-layer LCL
- 1230 m above ground
- 0-6 km bulk shear
- 9 kt
- 0-1 km storm-relative helicity
- -16 m²/s²
- 0-3 km storm-relative helicity
- 11 m²/s²
- Significant tornado parameter
- 0.0
- Supercell composite
- 0.0
The text
As transmitted.
574 WGUS61 KPHI 261930 FFAPHI URGENT - IMMEDIATE BROADCAST REQUESTED Flood Watch National Weather Service Mount Holly NJ 330 PM EDT Thu Aug 26 2021 DEZ001-NJZ007>010-012>022-026-027-PAZ060>062-070-071-101>106-270915- /O.NEW.KPHI.FF.A.0008.210827T1800Z-210829T0600Z/ /00000.0.ER.000000T0000Z.000000T0000Z.000000T0000Z.OO/ New Castle-Warren-Morris-Hunterdon-Somerset-Middlesex-Western Monmouth-Eastern Monmouth-Mercer-Salem-Gloucester-Camden- Northwestern Burlington-Ocean-Cumberland-Atlantic-Coastal Ocean- Southeastern Burlington-Berks-Lehigh-Northampton-Delaware- Philadelphia-Western Chester-Eastern Chester-Western Montgomery- Eastern Montgomery-Upper Bucks-Lower Bucks- Including the cities of Glassboro, Jackson, Flemington, Allentown, Easton, Philadelphia, Doylestown, Chalfont, Morristown, Pennsville, Reading, Lansdale, Norristown, Honey Brook, Mount Holly, Cherry Hill, Moorestown, Freehold, Pottstown, Hammonton, Media, Oxford, Kennett Square, Sandy Hook, Morrisville, West Chester, Millville, Wilmington, New Brunswick, Trenton, Wharton State Forest, Washington, Collegeville, Long Beach Island, Camden, Bethlehem, Perkasie, and Somerville 330 PM EDT Thu Aug 26 2021 ...FLASH FLOOD WATCH IN EFFECT FROM FRIDAY AFTERNOON THROUGH LATE SATURDAY NIGHT... The National Weather Service in Mount Holly has issued a * Flash Flood Watch for portions of northern Delaware...New Jersey... and Pennsylvania...including the following areas...in northern Delaware...New Castle. In New Jersey...Atlantic, Camden, Coastal Ocean, Cumberland, Eastern Monmouth, Gloucester, Hunterdon, Mercer, Middlesex, Morris, Northwestern Burlington, Ocean, Salem, Somerset, Southeastern Burlington, Warren, and Western Monmouth. In Pennsylvania...Berks, Delaware, Eastern Chester, Eastern Montgomery, Lehigh, Lower Bucks, Northampton, Philadelphia, Upper Bucks, Western Chester, and Western Montgomery. * From Friday afternoon through late Saturday night. * A slow moving frontal boundary will move into a warm and very humid air mass by Friday afternoon. This will likely trigger multiple rounds of thunderstorms from Friday afternoon through much of Saturday. Storms are likely to be slow moving and produce torrential rain. A general 1 to 3 inches of rain is forecast, but locally higher totals over 5 inches are possible. Combined with wet antecedent conditions, this could lead to flash flooding. PRECAUTIONARY/PREPAREDNESS ACTIONS... You should monitor later forecasts and be prepared to take action should Flash Flood Warnings be issued. && $$ JEO
5 follow-up statements
834 WGUS61 KPHI 270804 FFAPHI Flood Watch National Weather Service Mount Holly NJ 404 AM EDT Fri Aug 27 2021 DEZ001-NJZ007>010-012>022-026-027-PAZ060>062-070-071-101>106-272115- /O.CON.KPHI.FF.A.0008.210827T1800Z-210829T0600Z/ /00000.0.ER.000000T0000Z.000000T0000Z.000000T0000Z.OO/ New Castle-Warren-Morris-Hunterdon-Somerset-Middlesex-Western Monmouth-Eastern Monmouth-Mercer-Salem-Gloucester-Camden- Northwestern Burlington-Ocean-Cumberland-Atlantic-Coastal Ocean- Southeastern Burlington-Berks-Lehigh-Northampton-Delaware- Philadelphia-Western Chester-Eastern Chester-Western Montgomery- Eastern Montgomery-Upper Bucks-Lower Bucks- Including the cities of Glassboro, Jackson, Flemington, Allentown, Easton, Philadelphia, Doylestown, Chalfont, Morristown, Pennsville, Reading, Lansdale, Norristown, Honey Brook, Mount Holly, Cherry Hill, Moorestown, Freehold, Pottstown, Hammonton, Media, Oxford, Kennett Square, Sandy Hook, Morrisville, West Chester, Millville, Wilmington, New Brunswick, Trenton, Wharton State Forest, Washington, Collegeville, Long Beach Island, Camden, Bethlehem, Perkasie, and Somerville 404 AM EDT Fri Aug 27 2021 ...FLASH FLOOD WATCH REMAINS IN EFFECT FROM 2 PM EDT THIS AFTERNOON THROUGH LATE SATURDAY NIGHT... The Flash Flood Watch continues for * Portions of northern Delaware...New Jersey...and Pennsylvania... including the following areas...in northern Delaware...New Castle. In New Jersey...Atlantic, Camden, Coastal Ocean, Cumberland, Eastern Monmouth, Gloucester, Hunterdon, Mercer, Middlesex, Morris, Northwestern Burlington, Ocean, Salem, Somerset, Southeastern Burlington, Warren, and Western Monmouth. In Pennsylvania...Berks, Delaware, Eastern Chester, Eastern Montgomery, Lehigh, Lower Bucks, Northampton, Philadelphia, Upper Bucks, Western Chester, and Western Montgomery. * From 2 PM EDT this afternoon through late Saturday night. * A slow-moving weather system will affect the region today and Saturday. Thunderstorms are likely to develop this afternoon and evening, with additional storms possible tonight through much of Saturday. With hot and humid conditions in advance of this system, storms will likely produce torrential downpours. As storms are also expected to be slow-moving, there is elevated potential for localized flash flooding, especially in more vulnerable urban areas and in locations that received substantial rainfall during the past couple of weeks. PRECAUTIONARY/PREPAREDNESS ACTIONS... You should monitor later forecasts and be prepared to take action should Flash Flood Warnings be issued. && $$ CMS
995 WGUS61 KPHI 272007 FFAPHI Flood Watch National Weather Service Mount Holly NJ 407 PM EDT Fri Aug 27 2021 DEZ001-NJZ007>010-012>022-026-027-PAZ060>062-070-071-101>106-281000- /O.CON.KPHI.FF.A.0008.000000T0000Z-210829T0600Z/ /00000.0.ER.000000T0000Z.000000T0000Z.000000T0000Z.OO/ New Castle-Warren-Morris-Hunterdon-Somerset-Middlesex-Western Monmouth-Eastern Monmouth-Mercer-Salem-Gloucester-Camden- Northwestern Burlington-Ocean-Cumberland-Atlantic-Coastal Ocean- Southeastern Burlington-Berks-Lehigh-Northampton-Delaware- Philadelphia-Western Chester-Eastern Chester-Western Montgomery- Eastern Montgomery-Upper Bucks-Lower Bucks- Including the cities of Glassboro, Jackson, Flemington, Allentown, Easton, Philadelphia, Doylestown, Chalfont, Morristown, Pennsville, Reading, Lansdale, Norristown, Honey Brook, Mount Holly, Cherry Hill, Moorestown, Freehold, Pottstown, Hammonton, Media, Oxford, Kennett Square, Sandy Hook, Morrisville, West Chester, Millville, Wilmington, New Brunswick, Trenton, Wharton State Forest, Washington, Collegeville, Long Beach Island, Camden, Bethlehem, Perkasie, and Somerville 407 PM EDT Fri Aug 27 2021 ...FLASH FLOOD WATCH REMAINS IN EFFECT THROUGH LATE SATURDAY NIGHT... The Flash Flood Watch continues for * Portions of northern Delaware...New Jersey...and Pennsylvania... including the following areas...in northern Delaware...New Castle. In New Jersey...Atlantic, Camden, Coastal Ocean, Cumberland, Eastern Monmouth, Gloucester, Hunterdon, Mercer, Middlesex, Morris, Northwestern Burlington, Ocean, Salem, Somerset, Southeastern Burlington, Warren, and Western Monmouth. In Pennsylvania...Berks, Delaware, Eastern Chester, Eastern Montgomery, Lehigh, Lower Bucks, Northampton, Philadelphia, Upper Bucks, Western Chester, and Western Montgomery. * Through late Saturday night. * A slow-moving weather system will continue to affect the region through Saturday. Additional rounds of thunderstorms remain possible tonight through much of Saturday. With the hot and humid conditions in advance of this system, storms will likely continue to produce torrential downpours. As storms are also expected to be slow-moving, there is elevated potential for localized flash flooding, especially in more vulnerable urban areas and in locations that received substantial rainfall during the past couple of weeks. PRECAUTIONARY/PREPAREDNESS ACTIONS... You should monitor later forecasts and be prepared to take action should Flash Flood Warnings be issued. && $$ JEO
443 WGUS61 KPHI 280650 FFAPHI URGENT - IMMEDIATE BROADCAST REQUESTED Flood Watch National Weather Service Mount Holly NJ 250 AM EDT Sat Aug 28 2021 DEZ001-NJZ007>010-012>019-PAZ060>062-070-071-101>106-280800- /O.CAN.KPHI.FF.A.0008.000000T0000Z-210829T0600Z/ /00000.0.ER.000000T0000Z.000000T0000Z.000000T0000Z.OO/ New Castle-Warren-Morris-Hunterdon-Somerset-Middlesex-Western Monmouth-Eastern Monmouth-Mercer-Salem-Gloucester-Camden- Northwestern Burlington-Berks-Lehigh-Northampton-Delaware- Philadelphia-Western Chester-Eastern Chester-Western Montgomery- Eastern Montgomery-Upper Bucks-Lower Bucks- Including the cities of Glassboro, Sandy Hook, Flemington, Media, Philadelphia, Doylestown, Chalfont, Morristown, Pennsville, Honey Brook, Lansdale, Norristown, Reading, Mount Holly, Cherry Hill, Moorestown, Freehold, Pottstown, Allentown, Oxford, Kennett Square, Easton, West Chester, Morrisville, Wilmington, New Brunswick, Trenton, Washington, Collegeville, Camden, Bethlehem, Perkasie, and Somerville 250 AM EDT Sat Aug 28 2021 ...FLASH FLOOD WATCH IS CANCELLED... The Flash Flood Watch for portions of northern Delaware...New Jersey...and Pennsylvania...including the following areas...in northern Delaware...New Castle. In New Jersey...Camden, Eastern Monmouth, Gloucester, Hunterdon, Mercer, Middlesex, Morris, Northwestern Burlington, Salem, Somerset, Warren, and Western Monmouth. In Pennsylvania...Berks, Delaware, Eastern Chester, Eastern Montgomery, Lehigh, Lower Bucks, Northampton, Philadelphia, Upper Bucks, Western Chester, and Western Montgomery has been cancelled. Heavy rain will be focused on portions of southeast New Jersey. Therefore, the Flood Watch is cancelled. $$ NJZ020>022-026-027-281900- /O.EXT.KPHI.FF.A.0008.000000T0000Z-210829T0300Z/ /00000.0.ER.000000T0000Z.000000T0000Z.000000T0000Z.OO/ Ocean-Cumberland-Atlantic-Coastal Ocean-Southeastern Burlington- Including the cities of Wharton State Forest, Millville, Jackson, Hammonton, and Long Beach Island 250 AM EDT Sat Aug 28 2021 ...FLASH FLOOD WATCH NOW IN EFFECT THROUGH THIS EVENING... The Flash Flood Watch is now in effect for * A portion of southern New Jersey...including the following areas... Atlantic, Coastal Ocean, Cumberland, Ocean, and Southeastern Burlington. * Through this evening. * A slow-moving cold front will affect mainly southeast New Jersey through this evening. Additional rounds of showers and thunderstorms remain possible through this afternoon. With abundant low level moisture over the area, torrential downpours are likely. As storms are also expected to be slow-moving, there is an elevated potential for localized flash flooding, especially in locations that received substantial rainfall during the past couple of weeks. PRECAUTIONARY/PREPAREDNESS ACTIONS... You should monitor later forecasts and be prepared to take action should Flash Flood Warnings be issued. && $$ MPS
578 WGUS61 KPHI 281850 FFAPHI Flood Watch National Weather Service Mount Holly NJ 250 PM EDT Sat Aug 28 2021 NJZ020>022-026-027-290300- /O.CON.KPHI.FF.A.0008.000000T0000Z-210829T0300Z/ /00000.0.ER.000000T0000Z.000000T0000Z.000000T0000Z.OO/ Ocean-Cumberland-Atlantic-Coastal Ocean-Southeastern Burlington- Including the cities of Wharton State Forest, Millville, Jackson, Hammonton, and Long Beach Island 250 PM EDT Sat Aug 28 2021 ...FLASH FLOOD WATCH REMAINS IN EFFECT UNTIL 11 PM EDT THIS EVENING... The Flash Flood Watch continues for * A portion of southern New Jersey...including the following areas... Atlantic, Coastal Ocean, Cumberland, Ocean, and Southeastern Burlington. * Until 11 PM EDT this evening. * Additional rounds of showers and thunderstorms will be possible through the afternoon into early this evening. Any showers or storms that develop will have the potential to produce torrential downpours. Storms will also be slow moving. The combination of these factors will lead to an increased risk for flash flooding through this time. $$ SFJ
888 WGUS61 KPHI 281939 FFAPHI Flood Watch National Weather Service Mount Holly NJ 339 PM EDT Sat Aug 28 2021 NJZ020>022-026-027-282045- /O.CAN.KPHI.FF.A.0008.000000T0000Z-210829T0300Z/ /00000.0.ER.000000T0000Z.000000T0000Z.000000T0000Z.OO/ Ocean-Cumberland-Atlantic-Coastal Ocean-Southeastern Burlington- Including the cities of Wharton State Forest, Millville, Jackson, Hammonton, and Long Beach Island 339 PM EDT Sat Aug 28 2021 ...FLASH FLOOD WATCH IS CANCELLED... The Flash Flood Watch for a portion of southern New Jersey... including the following areas...Atlantic, Coastal Ocean, Cumberland, Ocean, and Southeastern Burlington has been cancelled. The Flood Watch is cancelled. Flooding is no longer expected to pose a threat. $$ SFJ
The office that day
Everything else NWS Philadelphia/Mount Holly issued on the same UTC day.
| Issued | Product | Office | Counties | Lasted |
|---|---|---|---|---|
| Aug 26, 4:28 PM EDT | Areal Flood Advisory | PHI | Ocean | 3 hr |
| Aug 26, 6:14 PM EDT | Special Weather Statement | PHI | Burlington | 31 min |
| Aug 26, 1:20 PM EDT | Severe Thunderstorm Warning | PHI | Monroe | 40 min |
| Aug 26, 5:02 PM EDT | Special Weather Statement | PHI | Monroe | 28 min |
| Aug 26, 5:29 PM EDT | Special Weather Statement | PHI | Monroe | 31 min |
| Aug 26, 5:35 PM EDT | Special Weather Statement | PHI | Carbon | 25 min |
| Aug 26, 5:59 PM EDT | Special Weather Statement | PHI | Carbon | 31 min |
| Aug 26, 6:09 PM EDT | Severe Thunderstorm Warning | PHI | Carbon, Monroe | 51 min |
| Aug 26, 6:24 PM EDT | Areal Flood Advisory | PHI | Carbon | 3 hr |
| Aug 26, 6:56 PM EDT | Special Weather Statement | PHI | Philadelphia | 34 min |
| Aug 26, 7:29 PM EDT | Areal Flood Advisory | PHI | Carbon | 2 hr |
| Aug 26, 2:36 PM EDT | Severe Thunderstorm Warning | PHI | Sussex | 43 min |
Nearby
Flash Flood Watches in New Jersey, 2021Flash Flood Watches in Pennsylvania, 2021Flash Flood Watches in Delaware, 2021Every flash flood watch in 2021
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.