textproduct: Philadelphia/Mt Holly

WHAT HAS CHANGED

Small increase in precipitation changes today, mainly for the southern Poconos.

A new Coastal Flood Advisory was issued for the South Jersey and Delaware Coast, as well as communities along Delaware Bay as widespread minor tidal flooding is expected this evening.

Upgraded the risk to MODERATE for rip currents today at all beaches.

The Storm Prediction Center has added a Slight Risk for Severe Weather next Friday. Key Message 4 will discuss the late week severe weather threat.

KEY MESSAGES

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

2. Relatively tranquil and seasonable through Monday, though a low chance (15-30%) of showers/isolated thunderstorms was added for the Pocono Plateau this afternoon.

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

4. Friday 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 tonight's high tide for the Atlantic coastline and Delaware Bay. Further Coastal Flood Advisories may be needed.

A relatively light onshore flow will continue through 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 tonight, a new Coastal Flood Advisory was issued for the South Jersey and Delaware coast as well as for 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 shows tides perhaps a touch higher compared to last night. Only spotty minor flooding is expected north of Atlantic City, so no Advisory is currently in place 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 pleasant through Monday, though a low chance (15-30%) of showers/isolated thunderstorms was added for the Pocono Plateau this afternoon.

We transition to a period of tranquil weather today as high pressure builds in. However, guidance continues to hint at some orographically-driven showers and isolated thunderstorms developing over the Pocono Plateau this afternoon. Have added around a 15-30% chance of precipitation for the afternoon and early evening, though not anticipating any significant impacts and the rest of the area should be dry. Dry conditions will continue through Monday.

Seasonable temperatures expected (or even a touch below normal) with low to mid 80s both days with lows in the low to mid 60s.

KEY MESSAGE 3...Above normal temperatures take over by Tuesday, likely continuing through the end of the week. Wednesday may 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 increasingly likely for at least some of the area as temperatures should get well into the 90s with increasing humidity.

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...Friday 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 Friday. 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.

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 /08Z SUNDAY THROUGH THURSDAY/

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

Rest of Tonight (through 12z)...VFR for the Lehigh Valley terminals. Brief MVFR conditions possible at the I-95 terminals as a BKN/SCT stratus deck appears to be right near the I-95 corridor. Thinking that dissipates by 11z-12z but brief periods of MVFR conditions are possible (25-30% chance).

Story is a little different for KMIV/KACY. Expecting MVFR/IFR conditions for the next couple hours until drier air moves in. Patchy fog is also possible given these two sites saw a good amount of rainfall today.

Winds out of the northeast around 3 to 8 kt. Moderate confidence.

Today...VFR. Main challenge today will be timing of wind shifts as winds gradually veer through the day, starting east/northeast and ending the day out of the south/southeast. Winds will be around 5 to 10 kt with some gusts up to 20 kt possible at KACY. High confidence in prevailing VFR. Moderate confidence in timing of wind shifts.

Sunday Night...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.

Outlook...

Monday through Thursday...VFR. No significant weather.

MARINE

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

Outlook...

Monday through Thursday...No marine headlines expected.

Rip Currents...

For today, onshore flow strengthens with winds around 10 to 20 MPH (higher end of that range across southern areas). Wave guidance shows multiple swell groups as well with one secondary swell being around 10 seconds. Breaking waves of 2 to 4 feet are expected. With modest onshore flow and a 10 second swell among multiple swell groups, all beaches have been upgraded to a MODERATE risk for the development of rip currents.

For Monday, winds weaken to around 10 MPH or less with wave heights slightly lower as well. Wave guidance now only has one swell group of around 6 seconds. A southeasterly swell does develop and we get within a day of the New Moon, however with a short period, relatively light winds, and low breaking waves, a LOW risk for the development of rip currents should be sufficient for now.

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

PHI WATCHES/WARNINGS/ADVISORIES

PA...None. NJ...Coastal Flood Advisory from 8 PM this evening to midnight EDT tonight for NJZ016. Coastal Flood Advisory from 5 PM this afternoon to 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 from 5 PM this afternoon to 11 PM EDT this evening for DEZ002>004. MD...None. MARINE...None.