textproduct: Philadelphia/Mt Holly

WHAT HAS CHANGED

A Small Craft Advisory has been issued for Atlantic Ocean coastal waters on Monday.

Increasing confidence in well above normal temperatures next week and a legitimate chance for the first 90 degree of 2026 for Philadelphia. Above normal temperatures could also continue into next weekend, with highs in the 80s for most.

KEY MESSAGES

1. A mainly dry weather pattern continues today, continuing the elevated risk for fire spread.

2. Frost possible across portions of southeast Pennsylvania early this morning.

3. A significant warm up is expected for the early and middle part of next week with temperatures anticipated to reach 90F for the first time this season along portions of the I-95 corridor on Wednesday and potentially Thursday.

DISCUSSION

KEY MESSAGE 1...A mainly dry weather pattern continues today, continuing the elevated risk for fire spread.

Continued dry weather today will lead to another day with an elevated risk for fire spread. Conditions will be slightly less favorable today (compared to Saturday) for fire spread with a little more moisture moving back into the region with east- southeasterly winds. Minimum RH values will still fall around 30-40% though with winds gusting up to around 20 mph.

KEY MESSAGE 2...Frost possible across portions of southeast Pennsylvania early this morning.

With high pressure moving overhead early this morning, calm winds and clear skies have led to early morning lows in the low to mid 30s for many areas north and west of the I-95 corridor. Despite a dry airmass in place, dew point depressions are sufficient to support the potential for patchy frost. A Frost Advisory has been issued for Berks, western Chester, and western Montgomery counties through early this morning where the growing season has begun. For the Lehigh Valley, Poconos, and northern New Jersey, patchy frost is possible, but the growing season there has not begun yet.

KEY MESSAGE 3...A significant warm up is expected for the early and middle part of next week with temperatures anticipated to reach 90F for the first time this season along portions of the I-95 corridor on Wednesday and potentially Thursday.

Strong high pressure will gradually shift offshore Monday allowing for seasonable warm air to push north on southerly flow. This surge of warm air both at the low levels and aloft will push surface temps into the the low 80s Monday, the mid 80s Tuesday and into the upper 80s to low 90s for Wednesday and Thursday. Temperatures touching 90F in Philadelphia would mark the first 90 degree day of the year and the first since September of last year. As is typical in spring though, temperatures along and near the coast likely will be 15-25 degrees cooler due to the colder sea surface temperatures. While a cold front comes through on Thursday Night, temperatures likely stay above normal and remain in the upper 70s and low to mid 80s.

In addition to the strong WAA, winds on Monday could end up being fairly gusty. A low level jet will bring 35-45 kts close to the surface however with the inversion in place it will take most of the morning to erode it. Once the inversion erodes however,southerly gusts of 20-30 MPH can be expected Monday afternoon.

A series of weak disturbances will result in a slight chance to low- end chance (15-30%) for showers or even an isolated thunderstorm Tuesday through Thursday, primarily in the evening hours and primarily for areas northwest of the I-95 corridor. The bulk of the period will be high and dry however, and no area has higher than a 40% chance of rain any given day. This is not good news for the ongoing drought and things are expected to get worse.

AVIATION /12Z SUNDAY THROUGH THURSDAY/

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

Today...VFR. Winds east around 5-10 kts in the morning shift to the S-SE and gust to 15-20 kts in the afternoon. High confidence.

Tonight...VFR. Southerly winds around 5-10 kts with a few gusts around 15 kts. LLWS likely after 05Z with winds around 40-45 kts developing at 2 kft. Moderate-high confidence.

Outlook...

Monday...Primarily VFR. Chance of showers at KRDG/KABE (25-35% and a slight chance of showers (15-20%) in the afternoon, though not expecting anything significant. Southwest wind gusts of 20-25 kt anticipated.

Monday Night through Tuesday Night...VFR. No significant weather.

Wednesday through Wednesday Night...Primarily VFR. Chance of showers (25-40%) in the afternoon and evening at the I-95 and Lehigh Valley terminals could result in brief restrictions.

Thursday...VFR. No significant weather.

MARINE

Sub-SCA conditions expected through Sunday. Winds out of the NE around 10 kts shift SE during the day with gusts around 15-20 kts. Seas 2-4 feet.

Seas increase to around 5 feet late Sunday night/early Monday morning with southerly winds around 15 knots with gusts of 20-25 knots. A Small Craft Advisory has been issued for Atlantic Ocean coastal waters as a result. Sub-SCA conditions expected for the Delaware Bay.

Outlook...

Monday through Monday Night... A Small Craft Advisory is in place for all ocean zones as seas of 5 to 6 feet are expected. Sub-SCA conditions on Delaware Bay. Southwest winds around 15-20 kt with gusts up to 25 kt.

Tuesday through Thursday...No marine headlines expected.

CLIMATE

Warm temperatures well above normal are expected for the upcoming week. Wednesday is currently projected to be the warmest day, though Tuesday through Thursday could see some records broken depending on the site. Below are record highs and record high minimum temperatures for April 14th through April 16th.

Record High Temperatures April 14 Site Record/Year Allentown (ABE) 88/2023 AC Airport (ACY) 86/1945 AC Marina (55N) 90/1941 Georgetown (GED) 87/1977 Mount Pocono (MPO) 84/2023 Philadelphia (PHL) 91/1941 Reading (RDG) 90/1941 Trenton (TTN) 89/1941 Wilmington (ILG) 87/1941

Record Warmest Low Temperatures April 14 Site Record/Year Allentown (ABE) 61/2014 AC Airport (ACY) 63/2023 AC Marina (55N) 60/2023 Georgetown (GED) 65/2019 Mount Pocono (MPO) 56/2014 Philadelphia (PHL) 62/2014 Reading (RDG) 64/2014 Trenton (TTN) 62/2014 Wilmington (ILG) 60/2014

Record High Temperatures April 15 Site Record/Year Allentown (ABE) 86/1941 & 1994 AC Airport (ACY) 90/1967 AC Marina (55N) 86/1941 Georgetown (GED) 86/1960 & 2024 Mount Pocono (MPO) 82/1941 Philadelphia (PHL) 88/1941 Reading (RDG) 86/1941 & 1994 Trenton (TTN) 87/1994 Wilmington (ILG) 86/1896

Record Warmest Low Temperatures April 15 Site Record/Year Allentown (ABE) 59/2002 AC Airport (ACY) 61/2002 AC Marina (55N) 59/2006 Georgetown (GED) 65/2002 Mount Pocono (MPO) 58/2002 Philadelphia (PHL) 64/2002 Reading (RDG) 64/1938 Trenton (TTN) 63/2002 Wilmington (ILG) 62/2002

Record High Temperatures April 16 Site Record/Year Allentown (ABE) 90/2012 AC Airport (ACY) 89/2002 AC Marina (55N) 88/2002 Georgetown (GED) 89/2002 Mount Pocono (MPO) 85/2002 Philadelphia (PHL) 90/2002 Reading (RDG) 90/2012 Trenton (TTN) 91/2012 Wilmington (ILG) 92/1896

Record Warmest Low Temperatures April 16 Site Record/Year Allentown (ABE) 60/1941 AC Airport (ACY) 62/2002 AC Marina (55N) 64/2002 Georgetown (GED) 65/2012 Mount Pocono (MPO) 56/2002 Philadelphia (PHL) 62/2002 Reading (RDG) 65/1941 Trenton (TTN) 62/2002 Wilmington (ILG) 63/2002

PHI WATCHES/WARNINGS/ADVISORIES

PA...Frost Advisory until 8 AM EDT this morning for PAZ060-101-103. NJ...None. DE...None. MD...None. MARINE...Small Craft Advisory from 9 AM Monday to 1 AM EDT Tuesday for ANZ450. Small Craft Advisory from 4 AM Monday to 1 AM EDT Tuesday for ANZ451>454. Small Craft Advisory from 4 AM to 6 PM EDT Monday for ANZ455.