289 FXUS61 KPHI 241956 AFDPHI Area Forecast Discussion National Weather Service Mount Holly NJ 356 PM EDT Tue Jun 24 2025 .SYNOPSIS... Our significant heat wave will continue through Wednesday as hot high pressure remains centered over the Appalachians. The high will will eventually weaken and allow a back door cold front to track though much of the forecast area Thursday into Friday. The front will then push back to the north as a warm front on Saturday and Sunday. && .NEAR TERM /THROUGH WEDNESDAY/... Significant and dangerous heat will continue through Wednesday. For the remainder of the afternoon, we will see some of the hottest temperatures in over a decade across some locales. Temperatures will be a bit warmer compared to yesterday (mainly +1 to 2 degrees). At the same time, the pattern is favoring dewpoints to mix out a bit (slightly lower humidity). But in the end, our heat index values will not be very different compared to Monday. Like yesterday, a sea-breeze has developed, but it`s not expected to move too far inland. There are no changes to our headlines through tomorrow. Extreme Heat Warnings remain in effect for almost the entire area with the exception of the coastal beach zones and Carbon and Monroe counties where Heat Advisories are in place. Around the Delaware Valley, Lehigh Valley, and northern New Jersey, overnight temperatures could be the hottest observed in over a decade. There will be little relief tonight as temperatures remain in the mid 70s to around 80, likely even warmer in the most urban environments. Heat tends to have cumulative effects on the body and is exacerbated when the body can`t recover at night. If outside, drink water, take frequent breaks, and find some shade. Watch out for heat cramps, exhaustion, or stroke. Don`t leave people or pets in a closed car. If air conditioning is not available in your home, find a cooling option with friends or family or a nearby cooling station. && .SHORT TERM /WEDNESDAY NIGHT THROUGH THURSDAY NIGHT/... With the ridge beginning to break down and a cold front approaching from the north, a few showers and storms will be possible (POPs around 20-40%) beginning later on Wednesday and continuing into Wednesday night. With strong surface heating earlier in the day enhancing low-level instability, gusty winds could occur with any stronger storms, though marginal lapse rates and weak winds aloft should temper any severe threat. With the isolated showers and storms, increased cloud cover, and the approaching cold front, Wednesday night will be slightly cooler (though still quite warm). In general, lows are expected to be near 70 in the Poconos and along the coast, and in the mid 70s elsewhere. Thursday, the ridge will continue to become further suppressed and continue to shift south of the region as a backdoor cold front crosses the region from the north during the morning and eventually clearing the area Thursday evening. Temperature-wise, areas north of the front will be noticeably cooler with afternoon highs in the upper 70s to mid 80s. For areas south of the cold front, high temperatures on Thursday are expected to rise into the upper 80s and low 90s. For these areas, it will remain humid, thus some heat indicies around 95-100 will be possible again, though with the faster progression of the front, these look to be mainly contained to Delmarva. By Thursday night, with the front through the area, overnight lows will fall back into the mid 60s to around 70. As the front crosses the region, scattered showers and storms will become likely during the afternoon and evening hours. Similar to Wednesday, marginal lapse rates and winds aloft will limit severe potential, but isolated instances of gusty winds could occur with the stronger storms. && .LONG TERM /FRIDAY THROUGH TUESDAY/... With the backdoor front south of the region on Friday and prevailing onshore flow from the east to east-northeast, we will get to enjoy a dramatically cooler day with cloudy skies and highs only in the upper 60s to upper 70s! A few showers and perhaps a thunderstorm will be possible as well through the day. Overnight lows will be cool and in the 60s. Southwesterly flow returns for the weekend with the backdoor front retreating northward as a warm front Saturday morning and high pressure over the southeast shifting offshore. As a result, temperatures will begin to warm back closer to climatology over the weekend and slightly above into the new week. Isolated, primarily diurnally driven convection, will be possible each day. A more active weather pattern may begin to take shape Tuesday and beyond, with indications of a slightly more amplified upper- air pattern taking shape. && .AVIATION /20Z TUESDAY THROUGH SUNDAY/... The following discussion is for KPHL, KPNE, KTTN, KABE, KRDG, KILG, KMIV, KACY and surrounding areas. Tonight...VFR. W to NW winds 5 kt or less. High confidence. Wednesday...Mainly VFR. Can`t rule out a shower/thunderstorm in the afternoon along with brief sub-VFR conditions. But any convection will be isolated. High confidence. Outlook... Wednesday night through Sunday...Mainly VFR. Brief periods of sub- VFR will be possible during the afternoon and evening hours each day in isolated to widely scattered showers and storms. && .MARINE... Tonight...Sub-SCA conditions expected. W to NW winds 10 kts or less. Seas around 2 feet. Wednesday...Sub-SCA conditions expected. NW winds 10 kts or less in morning becoming SE around 10 kts in the afternoon. Seas around 2 feet. Outlook... Wednesday night through Sunday...No marine headlines expected. Periods of showers and storms possible each day, but significant marine impacts are not anticipated. Rip Currents... For Wednesday, winds will be light out of the south at 5 to 10 mph or less. Waves in the surf zone will be around 1 to 2 feet with a dominant swell around 8 seconds. This set up will result in a LOW risk for the development of dangerous rip currents for both the Jersey shore and the Delaware Beaches. For Thursday, winds will turn more onshore out of the east at 10 to 15 mph with waves continuing to be around 1 to 2 feet with a dominant swell around 8 seconds. This set up with an onshore flow will result in a MODERATE risk for the development of dangerous rip currents for shore areas in Monmouth County NJ with a LOW risk continuing for the rest of the Jersey shore and the Delaware Beaches. For specific beach forecasts, visit weather.gov/beach/phi && .TIDES/COASTAL FLOODING... With the New Moon approaching tomorrow, June 25th, astronomical tides are increasing. Spotty minor tidal flooding was observed for the immediate coastline and back bays as well as within Delaware Bay last night. Expecting this to continue with the evening high tide for the next two nights and it`s possible for tomorrow evening`s high tide that some Advisories may end up being needed. Higher confidence in advisories potentially being needed starting Thursday evening. While we get away from the New Moon, onshore flow will result in water piling up and more widespread minor tidal flooding for the coastal and Delaware Bay communities. No tidal flooding is expected within the tidal Delaware River or Chesapeake Bay. && .CLIMATE... Near record breaking heat is expected across the area through the middle of the week. All climate sites except Wilmington and Georgetown set record highs and all climate sites except Reading set record warmest low temperatures for June 23rd. Additionally, Mount Pocono set their all-time record high temperature for June yesterday (June 23rd). The Atlantic City Marina and Wilmington tied their all time record warmest low temperature for June yesterday (June 23rd) as well. Further records are expected to fall into the week. Below is a look at the last 100 degree day, daily record high maximum and minimum temperature for all of our climate sites. Most Recent 100 Degree Day Site Date/Temperature Allentown (ABE) July 22, 2011/104 AC Airport (ACY) July 21, 2019/100 AC Marina (55N) July 5, 1999/101 Georgetown (GED) July 21, 2019/100 Mount Pocono (MPO) July 3, 1911/103 Philadelphia (PHL) July 18, 2012/100 Reading (RDG) June 22, 2024/101 Trenton (TTN) July 18, 2012/100 Wilmington (ILG) July 18, 2012/101 Record High Temperatures June 24 Site Record/Year Allentown (ABE) 98/1923 AC Airport (ACY) 99/2010 AC Marina (55N) 95/2002 Georgetown (GED) 97/2010 Mount Pocono (MPO) 92/1914 Philadelphia (PHL) 99/1923 Reading (RDG) 98/1908 & 1923 Trenton (TTN) 98/1894 Wilmington (ILG) 102/1894 Record Warmest Low Temperatures June 24 Site Record/Year Allentown (ABE) 71/2010 AC Airport (ACY) 72/1951, 2013, 2017 & 2024 AC Marina (55N) 72/1924, 2002, 2010, 2011, 2013 & 2020 Georgetown (GED) 74/2010 Mount Pocono (MPO) 66/1960, 1964 & 2002 Philadelphia (PHL) 75/1909, 1921, 1994 & 2020 Reading (RDG) 73/1909, 1994 & 2010 Trenton (TTN) 76/1894 & 2010 Wilmington (ILG) 74/1994 Record High Temperatures June 25 Site Record/Year Allentown (ABE) 98/1923 AC Airport (ACY) 96/1997 AC Marina (55N) 95/1952 Georgetown (GED) 96/1952 Mount Pocono (MPO) 91/1952 Philadelphia (PHL) 98/1952 Reading (RDG) 99/1943 Trenton (TTN) 99/1997 Wilmington (ILG) 98/1894 Record Warmest Low Temperatures June 25 Site Record/Year Allentown (ABE) 74/1923 & 1976 AC Airport (ACY) 80/1950 AC Marina (55N) 75/1997 & 2002 Georgetown (GED) 75/2019 Mount Pocono (MPO) 69/1952 Philadelphia (PHL) 76/1909, 1976 & 2002 Reading (RDG) 75/1943 & 1949 Trenton (TTN) 75/1976 Wilmington (ILG) 75/1976 && .PHI WATCHES/WARNINGS/ADVISORIES... PA...Extreme Heat Warning until 8 PM EDT Wednesday for PAZ060>062- 070-071-101>106. Heat Advisory until 8 PM EDT Wednesday for PAZ054-055. Air Quality Alert until midnight EDT tonight for PAZ070-071- 101>106. NJ...Extreme Heat Warning until 8 PM EDT Wednesday for NJZ001- 007>010-012-013-015>023-027. Heat Advisory until 8 PM EDT Wednesday for NJZ014-024>026. Air Quality Alert until midnight EDT tonight for NJZ012>027. DE...Extreme Heat Warning until 8 PM EDT Wednesday for DEZ001>003. Heat Advisory until 8 PM EDT Wednesday for DEZ004. MD...Extreme Heat Warning until 8 PM EDT Wednesday for MDZ012-015- 019-020. MARINE...None. && $$ SYNOPSIS...Kruzdlo NEAR TERM...Hoeflich/Kruzdlo SHORT TERM...AKL/Cooper/MJL LONG TERM...AKL/Cooper/MJL AVIATION...AKL/Kruzdlo MARINE...AKL/Fitzsimmons/Kruzdlo TIDES/COASTAL FLOODING... CLIMATE...