028 FXUS61 KPHI 290543 AFDPHI Area Forecast Discussion National Weather Service Mount Holly NJ 143 AM EDT Mon Jun 29 2026 .WHAT HAS CHANGED... New Key Message 1. Aviation section updated for 06Z TAFs and outlook. Additional temperature record information added to the Climate section. && .KEY MESSAGES... 1. A warming trend in temperatures expected through Tuesday. A few thunderstorms possible on Tuesday. 2. A large area of high pressure will set up over the Midwest, resulting in high heat and humidity over the Northeast and Mid- Atlantic. High temperatures will be well in the upper 90s to as high as 105 degrees with maximum heat index values between 100 and 110 degrees from Wednesday through Saturday. 3. There is the potential for afternoon and evening thunderstorms starting on Friday and lasting into the holiday weekend. && .DISCUSSION... KEY MESSAGE 1...A warming trend in temperatures expected through Tuesday. A few thunderstorms possible on Tuesday. A strengthening ridge of high pressure to our west will result in a warming trend in temperatures today through Tuesday. Highs will be in the mid to upper 80s today, and closer to 90 degrees for some areas by Tuesday. With a lack of low level moisture return locally until late Tuesday, dewpoints are anticipated to mix out each afternoon. So although it'll be quite warm, humidity won't be too oppressive until the heat ramps up on Wednesday. Lows in the 60s. By Tuesday afternoon and evening, we could get some MCSs coming into our region out of the Great Lakes region amid the northwesterly flow aloft. Greatest chances of any thunderstorms will be focused mainly north of the Philly metro. Details on this activity remains to be seen, but will be something to monitor. It is possible convection remains mainly north of our area. Damaging winds would be the main threat with any thunderstorms. KEY MESSAGE 2...A large area of high pressure will set up over the Midwest, resulting in high heat and humidity over the Northeast and Mid-Atlantic. High temperatures will be well in the upper 90s to as high as 105 degrees with maximum heat index values between 100 and 110 degrees from Wednesday through Saturday. Strong mid-level ridging develops over the Great Lakes and Ohio Valley early this week. The high then builds into the Northeast and Mid-Atlantic by Wednesday and continues through into the holiday weekend. In general, a west to southwest flow develops on Wednesday, then becomes more west to northwest by Friday. High temperatures will climb into the mid and upper 90s on Wednesday, and then from 100 to 105 on Thursday and Friday. Temperatures will abate somewhat on Saturday, returning to the mid and upper 90s. However, with dew points in the 60s and 70s, this will yield max heat index values from 105 to 110 during the two hottest days, which will be Thursday and Friday. Still, max heat index values will be 100 to 105 on Wednesday and Saturday. The Extreme Heat Watch remains in effect for New Jersey, southeast Pennsylvania, the Delaware Valley including Philadelphia and northern Delaware, and the southern Poconos. Future shifts will likely expand the Watch to include the rest of Delmarva. The mid-level ridge will break and retrograde back towards the south and west on Saturday, and a mid-level trough will try to slide down into the Northeast. This pattern change will begin to favor slightly cooler temperatures and a break in the extreme heat by Sunday or Monday, as well as the potential for showers and thunderstorms next weekend (see Key Message 3 below). KEY MESSAGE 3...There is the potential for afternoon and evening thunderstorms starting on Friday and lasting into the holiday weekend. The mid-level ridge looks to break down and retrograde back to the south and west starting on Friday, and this will allow mid- level troughiness to develop over the Northeast. With several shortwaves riding over the top of the ridge and into the local area, this may touch off afternoon and evening showers and thunderstorms starting on Friday, but the better chances for convection arrive on Saturday and Sunday. Currently, PoPs are around 20 percent (slight chance) on Friday and 30 to 50 percent (chance) on Saturday and Sunday. Given the high heat and humidity, cannot rule out at least a few stronger thunderstorms. && .AVIATION /06Z MONDAY THROUGH FRIDAY/... The following discussion is for KPHL, KPNE, KTTN, KABE, KRDG, KILG, KMIV, KACY and surrounding areas. Through 12Z...Restrictions are anticipated to develop for many terminals in fog/mist and low clouds moving in off the ocean. Winds mainly calm. Low confidence forecast in the details of restrictions. Rest of Today...Any restrictions clearing early (by 13Z), then VFR. ENE winds increasing to near 5-10 kts from I-95 and southeast, then shifting SE to S as sea, bay, and river breezes develop. Winds light and variable for RDG/ABE, eventually settling out of the south near 5 kts. High confidence. Tonight...Low chance of restrictions in fog overnight. Otherwise, VFR. Winds mainly calm. Low confidence in fog. Outlook... Tuesday through Friday...VFR. Low chance (20%) of a thunderstorm Tuesday and Friday, otherwise no significant weather. && .MARINE... Good conditions across the waters with sub-SCA continuing into the overnight. A couple scattered showers are possible across Delaware Bay or the southern NJ and Delaware waters, but the chances are rather low. Winds will remain light 5 to 10 knots from the E or SE. Similar conditions for Monday. Aside from the showers a little fog is possible overnight and into early Monday. Outlook... Monday night through Friday...Overall, sub-SCA conditions expected. Cannot rule out a brief period of southerly 25+ kt gusts or seas approaching 5 feet late Tuesday and/or Wednesday afternoon, mainly north of Barnegat Light. Rip Currents... For Monday, breaking waves in the surf zone will be around 2 feet or less with east to northeast winds around 10 mph and a southeast swell. As a result, there is a LOW risk of dangerous rip currents for both the Jersey Shore and Delaware Beaches. For Tuesday, conditions remain similar, with east to southeast winds around 10-15 mph and a southeast swell. Breaking waves in the surf zone will be around 1-2 feet as a result, and therefore, the LOW risk of dangerous rip currents for both the Jersey Shore and Delaware Beaches looks to continue. For specific beach forecasts, visit weather.gov/beach/phi && .CLIMATE... Record breaking heat is forecast from Wednesday through Saturday. Temperature records for our climate sites are listed below: All Time Record High Temperatures Site Record / Date Allentown (ABE) 105 / July 3, 1966 AC Airport (ACY) 106 / June 28, 1969 AC Marina (55N) 104 / August 7, 1918 Georgetown (GED) 104 / July 22 & 23, 2011 Mount Pocono (MPO) 103 / July 3, 1911 Philadelphia (PHL) 106 / August 7, 1918 Reading (RDG) 106 / July 22, 2011 Trenton (TTN) 106 / July 9, 1936 & July 22, 2011 Wilmington (ILG) 107 / August 7, 1918 All Time Record Warmest Low Temperatures Site Record / Date Allentown (ABE) 79 / July 15, 1995 AC Airport (ACY) 84 / July 23, 2011 AC Marina (55N) 82 / July 21, 2019 Georgetown (GED) 84 / July 23, 2011 Mount Pocono (MPO) 76 / July 12, 1952 Philadelphia (PHL) 83 / July 24, 2010 & July 23, 2011 Reading (RDG) 81 / August 7, 1918 Trenton (TTN) 84 / August 11, 1895 Wilmington (ILG) 84 / August 7, 1918 Record Number of Consecutive 100+ Degree Days Site Record / Date Allentown (ABE) 3 days / July 9-11, 1936 & July 2-4, 1966 AC Airport (ACY) 3 days / July 2-4, 1966 & July 22-24, 2011 AC Marina (55N) 1 day / Occurred multiple times Georgetown (GED) 2 days / Most recent June 24-25, 2025 Mount Pocono (MPO) 1 day / July 3, 1911 Philadelphia (PHL) 3 days / July 2-4, 1966 & July 8-10, 1993 Reading (RDG) 3 days / Most recent July 21-23, 2011 Trenton (TTN) 3 days / Most recent July 21-23, 2011 Wilmington (ILG) 3 days / Most recent July 9-11, 1936 Record High Temperatures July 1 Site Record / Year Allentown (ABE) 98 / 2018 AC Airport (ACY) 99 / 1968 AC Marina (55N) 98 / 1968 Georgetown (GED) 99 / 2012 Mount Pocono (MPO) 88 / 1963, 1964, 1968, & 2018 Philadelphia (PHL) 102 / 1901 Reading (RDG) 101 / 1901 Trenton (TTN) 98 / 1898, 1901, & 1945 Wilmington (ILG) 97 / 1931 & 1963 Record Warmest Low Temperatures July 1 Site Record / Year Allentown (ABE) 74 / 1930 AC Airport (ACY) 77 / 1945 AC Marina (55N) 79 / 1945 Georgetown (GED) 76 / 1945 Mount Pocono (MPO) 67 / 1946, 1971, 2013, 2017, 2025 Philadelphia (PHL) 82 / 1901 Reading (RDG) 76 / 1968 Trenton (TTN) 77 / 1945 Wilmington (ILG) 75 / 2013 Record High Temperatures July 2 Site Record / Year Allentown (ABE) 102 / 1966 AC Airport (ACY) 100 / 1966 AC Marina (55N) 97 / 1968 Georgetown (GED) 99 / 1953 Mount Pocono (MPO) 93 / 1911 Philadelphia (PHL) 103 / 1901 Reading (RDG) 102 / 1966 Trenton (TTN) 100 / 1901 Wilmington (ILG) 98 / 1941 & 1966 Record Warmest Low Temperatures July 2 Site Record / Year Allentown (ABE) 75 / 2013 AC Airport (ACY) 79 / 2002 AC Marina (55N) 76 / 2012 Georgetown (GED) 77 / 1959 Mount Pocono (MPO) 70 / 1903 Philadelphia (PHL) 82 / 1901 Reading (RDG) 79 / 1901 Trenton (TTN) 79 / 1901 Wilmington (ILG) 75 / 1941 & 2014 Record High Temperatures July 3 Site Record / Year Allentown (ABE) 105 / 1966 AC Airport (ACY) 104 / 1966 AC Marina (55N) 99 / 1919 Georgetown (GED) 101 / 1954 Mount Pocono (MPO) 103 / 1911 Philadelphia (PHL) 104 / 1966 Reading (RDG) 103 / 1898 & 1966 Trenton (TTN) 102 / 1966 Wilmington (ILG) 102 / 1966 Record Warmest Low Temperatures July 3 Site Record / Year Allentown (ABE) 75 / 2018 AC Airport (ACY) 78 / 2018 AC Marina (55N) 76 / 1983, 2002, & 2018 Georgetown (GED) 79 / 1953 Mount Pocono (MPO) 69 / 2013 Philadelphia (PHL) 77 / 1876, 1901, &2002 Reading (RDG) 76 / 2018 Trenton (TTN) 76 / 1901 & 1966 Wilmington (ILG) 76 / 2002 Record High Temperatures July 4 Site Record / Year Allentown (ABE) 102 / 1949 AC Airport (ACY) 102 / 1966 AC Marina (55N) 99 / 1966 Georgetown (GED) 100 / 1966 Mount Pocono (MPO) 99 / 1911 Philadelphia (PHL) 103 / 1966 Reading (RDG) 100 / 1911 & 1966 Trenton (TTN) 99 / 1919, 1999, & 2010 Wilmington (ILG) 102 / 1966 Record Warmest Low Temperatures July 4 Site Record / Year Allentown (ABE) 75 / 1999 AC Airport (ACY) 75 / 1974, 1983, 1999, & 2002 AC Marina (55N) 79 / 2002 Georgetown (GED) 75 / 1999 & 2012 Mount Pocono (MPO) 70 / 2002 & 2013 Philadelphia (PHL) 79 / 1919 Reading (RDG) 78 / 1966 Trenton (TTN) 78 / 1966 Wilmington (ILG) 76 / 1999 && .PHI WATCHES/WARNINGS/ADVISORIES... PA...Extreme Heat Watch from Wednesday afternoon through Saturday evening for PAZ054-055-060>062-070-071-101>106. NJ...Extreme Heat Watch from Wednesday afternoon through Saturday evening for NJZ001-007>010-012>027. DE...Extreme Heat Watch from Wednesday afternoon through Saturday evening for DEZ001. MD...None. MARINE...None. && $$ DISCUSSION...Fitzsimmons/MPS/OHara AVIATION...MPS/Staarmann MARINE...AKL/MPS/OHara