textproduct: Philadelphia/Mt Holly

WHAT HAS CHANGED

Updated Key Message 1.

KEY MESSAGES

1. Minor tidal flooding will continue with this evening's high tide for the Atlantic coastline and Delaware Bay. Further Coastal Flood Advisories may be needed.

2. Relatively tranquil and seasonable through Monday. There is a low chance (15-30%) of a shower or isolated thunderstorm for the north/west areas this afternoon.

3. Above normal temperatures take over by Tuesday, likely continuing toward the end of the week. Wednesday will likely need heat headlines.

4. Late week could be active and unsettled with a chance for showers and thunderstorms, some of which could be severe.

DISCUSSION

KEY MESSAGE 1...Minor tidal flooding will continue with this evening's high tide for the Atlantic coastline and Delaware Bay. Further Coastal Flood Advisories may be needed.

A relatively light onshore flow has continued today resulting in a minor push of water towards the coastline. Astronomical tides are also increasing with the upcoming New Moon on Tuesday. This will result in elevated tides with minor tidal flooding likely with the evening high tide cycle. The severity looks to remain within minor levels but will monitor how things trend over the coming days.

For this evening, a Coastal Flood Advisory remains in effect for the South Jersey and Delaware coast as well as the entirety of Delaware Bay including Salem and New Castle County for this evening's high tide. Widespread minor tidal flooding is expected again, and guidance has continued to show tides near or perhaps a touch higher compared to last night. Only spotty minor flooding is expected north of Atlantic City, so no Advisory has been issued for those areas.

Cannot rule out some spotty minor tidal flooding for communities along the Delaware River with the upcoming elevated tides. No tidal flooding is expected in our Eastern Shore zones along the Chesapeake Bay.

KEY MESSAGE 2... Relatively tranquil and seasonable through Monday. There is a low chance (15-30%) of a shower or isolated thunderstorm for the north/west areas late this afternoon.

High pressure builds in tonight and remains through Monday. There is a minor disturbance across the southern Poconos and near Berks county PA which could bring a few scattered showers into the evening. The short term models continue to show a signal for this (like they have for several runs now). We'll continue with this since satellite pics show some building clouds around there attm. Clear and seasonable cool tonight.

Pleasant weather for Monday with temps rising into the mid/upper 80s and low humidity levels. Could be the pick of the week weatherwise.

KEY MESSAGE 3...Above normal temperatures take over by Tuesday, likely continuing toward the end of the week. Wednesday will likely need heat headlines.

A more typical summertime pattern sets up beginning on Tuesday. Temperatures are expected to get above normal as ridging extends into the Mid-Atlantic from the west with surface high pressure strengthening offshore. This will set up warm southerly flow, allowing the heat and humidity to return, though not nearly as bad as how we started July. The heat peaks on Wednesday, where heat headlines look likely for at least some of the area as temperatures should get well into the 90s with increasing humidity. Its not out of the question PHL and a few other sites tag the century mark again, but its unlikely to reach the levels experienced early in the month.

A dry cold front looks to pass sometime late Wednesday which will knock down temperatures a bit, but medium range guidance and ensembles indicate above normal temperatures in the upper 80s/low 90s could remain through the end of the week and potentially into the weekend.

KEY MESSAGE 4...Late week could be active and unsettled with a chance for showers and thunderstorms, some of which could be severe.

We are still several days out but we are monitoring the severe weather setup on Thursday and Friday. A strong cold front will slide southward to break the heat ridge, putting potential for another round of severe weather in play. The Storm Prediction Center (SPC) has highlighted most of the area in a Slight Risk (15% chance of severe thunderstorms 25 miles from any point). Storms look to be driven by a strong cold front swinging in from the northwest and with ample daytime heating and instability, the ingredients are certainly there for strong to severe thunderstorms and damaging wind gusts. Timing is uncertain, as some of the latest guidance is somewhat faster with frontal progression.

In their long term outlook, SPC did mention some small MCS potential during the day 7 to 10 period as some shortwaves are likely to ripple through the northwest flow. Again, still several days out, but we will have to monitor the severe weather potential for the end of the week and possibly next weekend.

AVIATION /20Z SUNDAY THROUGH FRIDAY/

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

thru 00Z. VFR expected. A VCSH added for KRDG/KABE in case showers develop. East to Southeast winds around 10 knots. High confid.

Tonight...VFR. Winds generally out of the south around 5 kt or less though periods of calm likely especially for the second half of the night. High confidence.

Monday...VFR. South or Southwest winds up to 10 knots. High confid.

Outlook...

Tuesday through Friday...VFR for the most part. Showers and thunderstorms may re-enter the forecast Thursday and Friday, with brief sub-VFR conditions possible.

MARINE

Sub-SCA conditions expected through Monday with east/southeast winds around 10 to 15 kt and seas 2 to 3 feet.

Outlook...

Tuesday through Friday...Marginal small craft conditions may occur Wednesday with gusty southwesterly winds over the ocean waters. Gusts may reach 25 kts and waves may touch 5 feet.

Rip Currents...

For Monday, winds weaken to around 10 MPH or less with wave heights around 3 feet. A southeasterly swell develops and there is a period of around 7 seconds. There is also the New Moon on Tuesday. All of this said, the relatively light winds, low wave heights, and a bit of a shorter period will result in a LOW risk for the development of rip currents.

For Tuesday, winds become more shore parallel as they turn to be more out of the south-southwest and increase to 10-20 mph. For wave heights, these remain around 3 feet with a period of around 7 seconds. A southeasterly swell remains. The New Moon also falls on this day. All of this said, the winds becoming more shore parallel, low wave heights, and a bit of a shorter period will result in a LOW risk for the development of rip currents.

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

CLIMATE

A brief 1-day spike in temperatures is expected, with highs likely to approach records. Here are the records for Wednesday, July 15:

Allentown/ABE 98 in 1995 AC Airport/ACY 100 in 1995 AC Marina/55N 99 in 1995 Georgetown/GED 96 in 2024 and 1993 Mount Pocono/MPO 92 in 1954 Philadelphia/PHL 103 in 1995 Reading/RDG 100 in 1995 Trenton/TTN 101 in 1995 Wilmington/ILG 99 in 1997 and 1995

PHI WATCHES/WARNINGS/ADVISORIES

PA...None. NJ...Coastal Flood Advisory from 8 PM this evening to midnight EDT tonight for NJZ016. Coastal Flood Advisory until 11 PM EDT this evening for NJZ021>025. DE...Coastal Flood Advisory from 8 PM this evening to midnight EDT tonight for DEZ001. Coastal Flood Advisory until 11 PM EDT this evening for DEZ002>004. MD...None. MARINE...None.