textproduct: Philadelphia/Mt Holly

WHAT HAS CHANGED

Severe thunderstorm Watch has been cancelled.

KEY MESSAGES

1. Significantly cooler temperatures and several rounds of showers for the end of this week and the holiday weekend.

DISCUSSION

KEY MESSAGE 1...Significantly cooler temperatures and several rounds of showers for the end of this week and the holiday weekend.

A cold front will settle and stall to our south as we get into the holiday weekend. Some ripples of energy ride along and north of it and this looks to bring some rounds of showers to our region. A more organized surface low well to our west may provide an increase in showers or a period of rain later Friday and Saturday. The precipitation may become enhanced some as surface high pressure to our northeast wedges southwestward into our area creating some cool air damming. Furthermore, with PWAT values around 1.50-1.90 inches over the weekend, which is around the climatological maximum for this time of the year, there is at least a marginal chance for excessive rainfall on Saturday. We will be keeping an eye on how strong the baroclinic forcing gets along the stalled boundary wedged between the high to the northeast and the low to the west. Northeast flow along with several rounds of showers will all result in much cooler temperatures Thursday through Saturday, then some warming should take place Sunday and into Memorial Day. The pattern looks active though and therefore some additional showers are quite possible right into Memorial Day. While not great timing for the holiday weekend and unofficial start of summer, our region needs rain as a long-term drought continues.

AVIATION /00Z THURSDAY THROUGH MONDAY/

The following discussion is for KPHL, KPNE, KTTN, KABE, KRDG, KILG, KMIV, KACY and surrounding areas.

Tonight...Lingering MVFR with a few showers/tsra for KMIV/KACY for a few more hours then a return to VFR for the overnight. Patchy fog possible. Northwest winds 5 to 10 knots becoming North then Northeast late. Medium confid.

Thursday...Any VFR conditions during the morning will diminish to MVFR or IFR (especially for Delaware Valley and South) as the day progresses. Rains arrive from South to North thru the day. Northeast winds 10 to 15 kts with gusts 20 to 25 kts. Higher gusts especially near the shore areas. Low/medium confid.

Outlook...

Thursday Night through Monday...An unsettled pattern takes over with periods of MVFR/IFR conditions expected with several rounds of rain showers. Most widespread restrictions look to come Saturday and Saturday Night though the entire period likely will feature showers and low clouds with perhaps sporadic stretches of VFR if ceilings lift a bit.

MARINE

Following the (ongoing) showers and tstms, winds will becoming west then northwest. Overnight, winds turn north then northeast by Thursday morning. The northeast flow increases during Thursday and with a much cooler air mass moving in the mixing should become more efficient over the chilly ocean water. Seas will also build during Thursday. Opted to issue a Small Craft Advisory for Thursday afternoon for all waters except for the waters off Monmouth County and the upper Delaware Bay.

Outlook...

Thursday Night through Friday... A Small Craft Advisory is in effect for ocean zones south of Manasquan Inlet and the lower Delaware Bay as periods of 25-30 kt winds and seas nearing 5 feet are expected. Sub-SCA conditions expected on the upper Delaware Bay and coastal waters north of Manasquan Inlet.

Friday Night through Monday... SCA conditions expected with seas of 4 to 7 feet and periods of 25-30 kt winds, mainly on Saturday.

Rip Currents...

On Thursday, east to northeast winds will ramp up to 15 to 20 mph with gusts up to 25 mph. There will be a southeast swell with a period around 6 seconds and breaking waves of 1 to 3 feet. As a result, there is a MODERATE risk for the development of dangerous rip currents for the Jersey Shore and for Delaware Beaches.

On Friday, east to northeast winds will range from 15 to 20 mph with 25 to 30 mph gusts. There will be a southeast swell with a period of 10 to 13 seconds and breaking waves of 2 to 4 feet. This should result in a HIGH risk for the development of dangerous and lift threatening rip currents.

Although temperatures inland will mostly be in the 60s or so Thursday through Saturday, and even in the 50s well inland on Saturday, ocean temperatures will remain in the 50s. These cold water temperatures can quickly cause hypothermia and physical incapacitation to anyone suddenly immersed in the water.

For specific beach forecasts, visit weather.gov/beach/phi

CLIMATE

More record breaking temperatures are possible today.

Records for our climate sites are listed below:

Monthly Record High Temperatures for May

Site Record/Date Allentown (ABE) 97/May 19, 1962 AC Airport (ACY) 99/May 29, 1969 AC Marina (55N) 95/May 31, 1895 & May 23, 1925 Georgetown (GED) 98/May 28, 1991 Mount Pocono (MPO) 94/May 22, 1911 Philadelphia (PHL) 98/May 19, 2026 (new) Reading (RDG) 97/May 20, 1996 & May 19, 2026 Trenton (TTN) 99/May 23, 1911 & May 31, 1986 Wilmington (ILG) 98/May 10, 1895 & May 30, 1895

Monthly Record Warmest Low Temperatures for May

Site Record/Date Allentown (ABE) 71/May 31, 1975, May 28 & 31, 1991 AC Airport (ACY) 73/May 24, 2004 & May 19, 2017 AC Marina (55N) 73/May 30 & 31, 1987, & May 31, 1991 Georgetown (GED) 74/May 23, 1953 & May 20, 2019 Mount Pocono (MPO) 68/May 21, 1996 Philadelphia (PHL) 78/May 31, 1895 Reading (RDG) 72/May 28 & 31, 1939, May 31, 1991, & May 19, 2026 Trenton (TTN) 75/May 31, 1895 Wilmington (ILG) 75/May 30, 1895

Record High Temperatures May 20 Site Record/Year Allentown (ABE) 92/1962 & 1996 AC Airport (ACY) 96/1996 AC Marina (55N) 93/1996 Georgetown (GED) 95/1962 Mount Pocono (MPO) 89/1996 Philadelphia (PHL) 94/1962 & 1996 Reading (RDG) 97/1996 Trenton (TTN) 94/1996 Wilmington (ILG) 96/1996

Record Warmest Low Temperatures May 20 Site Record/Year Allentown (ABE) 66/2019 AC Airport (ACY) 68/1996(ties) AC Marina (55N) 69/1996 Georgetown (GED) 74/2019 Mount Pocono (MPO) 61/1959 Philadelphia (PHL) 71/2019 Reading (RDG) 69/1959 & 1996 Trenton (TTN) 68/1903, 1959, & 1962 Wilmington (ILG) 70/2019

PHI WATCHES/WARNINGS/ADVISORIES

PA...None. NJ...None. DE...None. MD...None. MARINE...Small Craft Advisory from 2 PM Thursday to 6 PM EDT Friday for ANZ431-451>455.