Several impulses of energy rotating within the flow of a mid-level low produced scattered thunderstorms over northern New Jersey during the mid to late evening hours. While most of these thunderstorms were sub-severe, one or two reports of isolated wind damage were reported.
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The episode as NWS PHI wrote it up.
Several impulses of energy rotating within the flow of a mid-level low produced scattered thunderstorms over northern New Jersey during the mid to late evening hours. While most of these thunderstorms were sub-severe, one or two reports of isolated wind damage were reported.
The local office's own words before the first event, 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 the first event at Jun 19, 2:52 PM EST, 5 hours 13 minutes earlier.
Area Forecast Discussion National Weather Service Mount Holly NJ 352 PM EDT Fri Jun 19 2020 .SYNOPSIS... Weakening mid-level low pressure will meander over the region before gradually weakening and moving to our northeast on Sunday. With persistent lee troughing developing at the surface over Pennsylvania and multiple waves of low pressure moving through the Great Lakes, a warm, muggy, and unsettled pattern is likely for much of next week. One of those areas of low pressure may bring a cold front through the region by late next week. && .NEAR TERM /THROUGH TONIGHT/... A mid-level low can currently be seen rotating over eastern OH this afternoon with weak lee-side troughing over central/ eastern PA. Along this weak surface convergence numerous showers and thunderstorms have initiated. Towards eastern PA and NJ coverage has been much more mixed. A dual sea breeze structure can be seen on radar and visible this afternoon across NJ. The initial sea breeze that moved inland late this morning has stalled across central NJ (as seen on KDIX), while another boundary can be seen closer to the coast (via a thin line of cu). Across the coastal counties and Pine Barrens of NJ the chance of precipitation looks very low (due to the stable layer of the sea breeze). Also across the eastern zones remnant 700 MB dry air has helped to suppress any convection. Over eastern PA and western NJ confluence of an inland moving sea breeze and a weak lee-side trough has allowed for scattered convection to form. Mean cloud bearing flow is only about 15/ 20 kts, so locally heavy rainfall will be the primary threat with these storms. Overnight tonight, convection will slowly wane as heating is lost. Another round of fog and stratus appears likely tonight as the low levels quickly saturate and winds remain near or at calm. Fog will most likely occur across KRDG (or areas it rained) as well as the coastal plain. && .SHORT TERM /SATURDAY AND SATURDAY NIGHT/... Saturday morning the upper level low will be centered over central PA, and be slowly heading east. As this occurs weak height falls will translate over the region with the lee-side trough setting up further east (just west of the I-95 corridor). PWATs also rise to around 1.6" Saturday afternoon. Given the increasing moisture, surface convergence close to I-95, and weak height falls, coverage looks much greater Saturday compared to Friday. 850/ 300 MB winds actually further weaken Saturday (only around 10 kts), so heavy rainfall will be the primary threat with these storms. Expect highs mostly in the mid 80s. && .LONG TERM /SUNDAY THROUGH FRIDAY/... Synoptic Overview: The mid-lvl low will open up and push to the NE on Sunday allowing the synoptic pattern to finally shift over the eastern US. To start the work-week, a progressive/ quasi-zonal flow regime will set up briefly, however the flow will quickly back to the SW as an amplified trough approaches by mid-week. At the surface, the pressure gradient will be fairly weak through the majority of the period with light southerly-southwesterly flow generally prevailing on the western side of the Atlantic High. This flow will be reinforced by areas of low pressure tracking over the Great Lakes and fairly persistent lee-troughing developing near our area. In general expect poorly organized diurnal convection to be a possible each afternoon as the warm and moist airmass persists through mid-week. Eventually one of the Great Lakes systems should bring a cold front through our area which would at least dry us out somewhat, and lower storm chances, but details regarding this mid-late week frontal passage are still uncertain. Dailies: Sunday... The low will push away Sunday, with some brief shortwave ridging trying to nose in its wake. Feel this will keep storms from becoming too widespread Sunday afternoon, so left PoPs generally in the 30-40% range. Although the southerly flow will keep the low-lvl moisture (dewpoints in the mid to upper 60s) in place, temperatures should "only" top out in the low to mid 80s. Monday/Tuesday... The warm up will kick into gear with high temperatures increasing into the upper 80s on Monday and then into the low- mid 90s on Tuesday. We will remain quite muggy with dewpoints near 70, so a heat advisory seems likely for the urban corridor on Tuesday with forecast heat indices in the upper 90s. Convection will be possible both days, with somewhat higher chances on Monday as a more defined shortwave looks to cross the area. As mentioned in previous discussions, shear looks to remain minimal so the severe threat appears low, and any convective concerns would likely be limited to localized hydro threats (due to PWATs around 1.75 inches, WCDs 10-13k ft, and weak storm motion). Wednesday/Friday... Forecast uncertainty increases considerably in this period, largely hinging on the timing and nature of a progged cold frontal passage. The EC continues to be very fast with the front, pushing it through by early Wednesday while the GFS lags the EC solution by around 36 hours (with the CMC indicating fropa on Wednesday). There are also some plausible solutions where the front stalls over Delmarva and then lifts a bit north Wed/Thursday before a stronger front finally kicks it out late week. Although the front would have a limited impact on temperatures (highs will still likely run above normal through Thursday) it would help scour out some of the low-lvl moisture which would in turn limit convective development. For now went with a blended approach for Td/PoPs (the most impacted parameters), but uncertainty is fairly high. && .AVIATION /19Z FRIDAY THROUGH WEDNESDAY/... The following discussion is for KPHL, KPNE, KTTN, KABE, KRDG, KILG, KMIV, KACY and surrounding areas. Today...All TAF sites are VFR this afternoon with a very weak pressure gradient, and therefore light southerly winds across the region. Towards the coastal TAF sites (KACY and KMIV) the sea breeze has already pushed inland and therefore no precipitation is expected at these locations. Towards the DE coast the sea breeze stalled rather close to the shore with convection initiating. Towards KRDG and KABE weak surface convergence has allowed for better coverage of showers and thunderstorms. Due to this, have included tempo groups for these western TAF sites. Brief restrictions possible in proximity to convection. Predominantly southerly winds up to 10 kt. Moderate confidence. Tonight...VFR probable during the evening, but another round of fog appears likely in spots. In particular, the crossover temperature looks most favorable at KRDG, while KTTN and KPNE will be in play. Light and variable winds. Low confidence. Saturday/Saturday night... Sub-VFR conditions rising to VFR after day break. Afternoon showers and thunderstorms likely. The greatest coverage appears to be across KPHL, KTTN, KILG, and KPNE. Stratus and fog will be possible again Saturday night particularly over areas that see rainfall during the day. Winds mainly 5 to 10 kt. Moderate Confidence. Outlook... Sunday... Showers and thunderstorms possible in the afternoon, particularly west of PHL, otherwise VFR. Southerly winds 5-10kts. High confidence. Monday-Wednesday: Possibly some low clouds/fog on Monday morning then prevailing VFR through the remainder of the period. Periods of showers and thunderstorms will be possible each afternoon with transient lowered flight categories possible. Prevailing SW winds 5-10kts. Moderate confidence. && .MARINE... Today through Saturday night...Sub-SCA conditions will continue through the near term with light southerly flow and wave heights around 2 to 4 feet. Areas of fog and stratus will again be possible during the nighttime and early morning hours tonight into Saturday morning. The chance of precipitation looks very low through Saturday night over the marine zones. Outlook... Sunday-Wednesday... Sub-SCA conditions are expected with generally light southerly-southwesterly winds and seas 2-4ft. Showers and Thunderstorms will be possible in the afternoon with occasional periods of fog and stratus possible overnight and in the morning (particularly early Monday) Rip Currents... With light winds and low seas expected through Saturday, the risk of dangerous rip current formation is low. && .EQUIPMENT... The NOAA Weather Radio All Hazards from Hibernia Park PA (WNG704) will remain off the air until further notice due to damage to the antenna during the June 3 derecho. && .PHI WATCHES/WARNINGS/ADVISORIES... PA...None. NJ...None. DE...None. MD...None. MARINE...None. && Synopsis...Carr Near Term...Haines Short Term...Haines Long Term...Carr Aviation...Carr/Haines Marine...Carr/Haines Equipment...
Hazardous Weather Outlook National Weather Service Mount Holly NJ 356 PM EDT Fri Jun 19 2020 DEZ002-003-MDZ012-015-019-020-NJZ001-007-008-010-012-013-016>023-027- PAZ054-055-060>062-202000- Kent-Inland Sussex-Kent MD-Queen Annes-Talbot-Caroline-Sussex-Warren- Morris-Somerset-Middlesex-Western Monmouth-Salem-Gloucester-Camden- Northwestern Burlington-Ocean-Cumberland-Atlantic-Cape May- Southeastern Burlington-Carbon-Monroe-Berks-Lehigh-Northampton- 356 PM EDT Fri Jun 19 2020 This Hazardous Weather Outlook is for central Delaware, southern Delaware, northeast Maryland, central New Jersey, northern New Jersey, southern New Jersey, east central Pennsylvania and northeast Pennsylvania. .DAY ONE...This afternoon and tonight. Patchy dense fog will be possible tonight. .DAYS TWO THROUGH SEVEN...Saturday through Thursday. The probability for widespread hazardous weather is low. .SPOTTER INFORMATION STATEMENT... Spotter activation is not expected at this time. DEZ004-NJZ014-024>026-202000- Delaware Beaches-Eastern Monmouth-Atlantic Coastal Cape May- Coastal Atlantic-Coastal Ocean- 356 PM EDT Fri Jun 19 2020 This Hazardous Weather Outlook is for southern Delaware, central New Jersey and southern New Jersey. .DAY ONE...This afternoon and tonight. Patchy dense fog will be possible tonight. .DAYS TWO THROUGH SEVEN...Saturday through Thursday. The probability for widespread hazardous weather is low. .SPOTTER INFORMATION STATEMENT... Spotter activation is not expected at this time. ANZ430-431-450>455-202000- 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- 356 PM EDT Fri Jun 19 2020 This Hazardous Weather Outlook is for Atlantic coastal waters and Delaware Bay Waters. .DAY ONE...This afternoon and tonight. Patchy dense fog will be possible tonight. .DAYS TWO THROUGH SEVEN...Saturday through Thursday. The probability for widespread hazardous weather is low. .SPOTTER INFORMATION STATEMENT... Spotter activation is not expected at this time. DEZ001-MDZ008-NJZ009-015-PAZ070-071-101>106-202000- New Castle-Cecil-Hunterdon-Mercer-Delaware-Philadelphia- Western Chester-Eastern Chester-Western Montgomery- Eastern Montgomery-Upper Bucks-Lower Bucks- 356 PM EDT Fri Jun 19 2020 This Hazardous Weather Outlook is for northern Delaware, northeast Maryland, central New Jersey, northwest New Jersey and southeast Pennsylvania. .DAY ONE...This afternoon and tonight. Slow moving scattered showers and thunderstorms will produce locally heavy rain this afternoon and evening. Patchy dense fog will be possible tonight. .DAYS TWO THROUGH SEVEN...Saturday through Thursday. The probability for widespread hazardous weather is low. .SPOTTER INFORMATION STATEMENT... Spotter activation is not expected at this time.
Special Weather Statement National Weather Service Mount Holly NJ 549 PM EDT Fri Jun 19 2020 PAZ060>062-103-105-192215- Upper Bucks-Lehigh-Western Montgomery-Northampton-Berks- 549 PM EDT Fri Jun 19 2020 ...A STRONG THUNDERSTORM WILL AFFECT EAST CENTRAL BERKS... SOUTHEASTERN LEHIGH...NORTH CENTRAL MONTGOMERY...NORTHWESTERN BUCKS AND SOUTHWESTERN NORTHAMPTON COUNTIES... At 548 PM EDT, a strong thunderstorm was located over Zionsville, or 10 miles south of Allentown, moving north at 20 mph. Wind gusts up to 30 mph and pea size hail are possible with this storm. Heavy rainfall is also occurring with this storm...and may cause ponding on roadways and poor drainage areas. Do not drive your vehicle through flooded roadways. Occasional cloud to ground lightning is occurring with this storm. Lightning can strike 15 miles away from a thunderstorm. If you see lightning or hear thunder seek a safe shelter inside a building or vehicle. Locations impacted include... Allentown, Bethlehem, Emmaus, Northampton, Hellertown, East Greenville, Bally, Bechtelsville, Coffeetown, Zionsville, Ancient Oaks, Lehigh University, Claussville, Geryville, Catasauqua, Fountain Hill, Pennsburg, Coplay, Macungie and North Catasauqua. This includes the following highways... Northeast Extension between mile markers 41 and 62. Interstate 78 in Pennsylvania between mile markers 49 and 69. LAT...LON 4067 7527 4039 7540 4037 7564 4067 7567 TIME...MOT...LOC 2148Z 192DEG 16KT 4044 7553 Robertson
Special Weather Statement National Weather Service Mount Holly NJ 740 PM EDT Fri Jun 19 2020 NJZ009-010-012-015-200015- Hunterdon-Somerset-Middlesex-Mercer- 740 PM EDT Fri Jun 19 2020 ...A STRONG THUNDERSTORM WILL AFFECT SOUTHEASTERN HUNTERDON...NORTH CENTRAL MERCER...SOUTHERN SOMERSET AND NORTH CENTRAL MIDDLESEX COUNTIES... At 740 PM EDT, a strong thunderstorm was located over Millstone, or near Somerville, moving northeast at 5 mph. Wind gusts up to 40 mph and pea size hail are possible with this storm. Locations impacted include... Somerville, Somerset, Middlesex, Bound Brook, Manville, Hopewell, Rocky Hill, Millstone, Skillman, Flagtown, Belle Mead, Martinsville, Society Hill, South Plainfield, Dunellen, Raritan and South Bound Brook. This includes the following highways... Interstate 78 in New Jersey between mile markers 38 and 39. Interstate 287 in New Jersey between mile markers 4 and 16. If outdoors, consider seeking shelter inside a building. Torrential rainfall is also occurring with this storm, and may cause localized flooding. Do not drive your vehicle through flooded roadways. LAT...LON 4055 7439 4033 7477 4041 7486 4066 7450 TIME...MOT...LOC 2340Z 234DEG 6KT 4052 7461 Davis
Special Weather Statement
National Weather Service Mount Holly NJ
855 PM EDT Fri Jun 19 2020
NJZ001-008-200130-
Morris-Sussex-
855 PM EDT Fri Jun 19 2020
...A STRONG THUNDERSTORM WILL AFFECT NORTHWESTERN MORRIS AND SOUTH
CENTRAL SUSSEX COUNTIES...
At 855 PM EDT, a strong thunderstorm was located over Hopatcong, or
near Newton, moving northeast at 30 mph.
Wind gusts up to 40 mph and pea size hail are possible with this
storm.
Locations impacted include...
Newton, Hopatcong, Wharton, Mount Arlington, Franklin, Stanhope,
Netcong, Ogdensburg, Branchville, Andover, Lake Mohawk, Succasunna,
Succasunna-Kenvil, Green Pond, Budd Lake and Lake Telemark.
This includes Interstate 80 in New Jersey between mile markers 23 and
34.
If outdoors, consider seeking shelter inside a building.
Torrential rainfall is also occurring with this storm, and may cause
localized flooding. Do not drive your vehicle through flooded
roadways.
LAT...LON 4107 7449 4104 7450 4105 7445 4104 7443
4103 7443 4103 7442 4082 7468 4090 7479
4091 7477 4094 7480 4118 7473
TIME...MOT...LOC 0055Z 206DEG 25KT 4096 7470
DavisThe Philadelphia radar (KDIX), 122 km away, was scanning. The volume nearest the first event began at 01:05 UTC.
1 thunderstorm wind. Local standard time, as filed.
Reports of trees and wires down near Underrock Road near Sparta. Time estimated from radar.
After NWS Directive 10-1605, the rules offices file Storm Data by.
Every storm in New Jersey in 2020Every state in 2020This day in weather historyWarnings in New Jersey, June 2020
NOAA National Centers for Environmental Information, Storm Events Database, compiled from the National Weather Service’s monthly Storm Data. Complete through 2026-06; NCEI adds each month about 75 days after it ends and revises past years a few times a year. Rebuilt 2026-09-24. Each event’s entry at NCEI: 889009.