textproduct: Philadelphia/Mt Holly

WHAT HAS CHANGED

No significant changes.

KEY MESSAGES

1. A significant warming trend will take place beginning this weekend and continuing into next week. High temperatures will climb into the mid 80s to near 90 by Sunday with low 90s expected for many areas Monday through Wednesday.

2. A cold front will bring chances of showers and thunderstorms to the region late Wednesday through Thursday, along with moderating temperatures closer to normal by the end of next week.

DISCUSSION

KEY MESSAGE 1...A significant warming trend will take place beginning this weekend and continuing into next week. High temperatures will climb into the mid 80s to near 90 by Sunday with low 90s expected for many areas Monday through Wednesday.

An upper level ridge builds into the Eastern US this weekend and into next week, bringing a period of above normal and summer-like temperatures. At the surface, high pressure over the western Atlantic anchors off the coast of the Mid Atlantic. This will result in a warm south to southwesterly flow for several days and gradually warming temperatures from Saturday through Tuesday or Wednesday.

Saturday will feature highs mainly in the upper 70s to low 80s with highs Sunday getting into the mid to upper 80s inland. Along the immediate coast it will generally be a good 5-10 degrees cooler.

Temperatures continue to climb into Monday for inland areas with mid to upper 80s for many areas, and low 90s over portions of eastern PA, inland southern NJ, and Delmarva. However the flow be more out of the south to even southeast so they'll be more of cooling influence near the coast and even extending a bit farther inland compared to Sunday. This will keep these areas near the coast mainly in the 70s to low 80s. Tuesday and potentially Wednesday could see some areas inland getting into the mid 90s but confidence on specific details becomes a bit lower by this time. The heat looks to break by Thursday. In terms of overall heat impacts, the current forecast has the urban corridor flirting with heat advisory criteria by next Tuesday into Wednesday, but that said, this particular setup doesn't look exceptionally favorable for both very high heat and humidity. Through Tuesday, mixing should keep dewpoints from getting too high. Evapotranspiration will be limited due to ongoing drought and ocean temperatures remain cool. Long story short, it is still quite early in the season for high dewpoints to combine with high heat. By the time these numbers creep up by Wednesday, clouds and showers/storms may help knock temperatures down some. In any case, we'll be getting close to record high temperature territory Monday through Wednesday of next week.

Temperatures will moderate closer to normal by late next week following a cold frontal passage late Wednesday.

KEY MESSAGE 2...A cold front will bring chances of showers and thunderstorms to the region late Wednesday through Thursday, along with moderating temperatures closer to normal by the end of next week.

Overall, the next 4 days look mostly dry, but can't rule out some diurnally driven showers/thunderstorms, mainly on Sunday. PoPs Sunday are mainly 10-20% as forcing looks weak and mid levels are dry. Could see some isolated convection focused near surface forcing mechanisms, such as higher terrain and the sea breeze. Surface flow will be westerly inland, but southerly near the coast, so this convergence zone could be something to help convection initiate. We will have a better idea once we get into range of the CAMs.

As mentioned earlier, a cold front will approach and likely bring an end to the stretch of above normal temperatures late next Wednesday. Convective activity will likely accompany that front in some form or fashion, but it's too early to speculate on specific impacts or hazards. The front looks to linger nearby or just south of the area late next week and this could keep some showers around at least into Thursday but perhaps even Friday.

AVIATION /00Z SATURDAY THROUGH WEDNESDAY/

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

Tonight...VFR expected. Winds diminish and become light and variable most places this evening and overnight. High confidence.

Saturday...VFR conditions expected. Winds increase out of the south to southeast 5-10 knots, with gusts 15-20 knots. High confidence.

Outlook...

Sunday through Tuesday...VFR prevailing with no significant weather expected. 10-20% chance of a shower or storm on Sunday.

Wednesday...Potential for sub VFR conditions with afternoon/evening showers and storms likely.

MARINE

Winds and seas are expected to remain below Craft Advisory levels through tonight. For Saturday, southerly winds increase with gusts up to 25 knots expected by late day into the evening. Seas will also be increasing to around 5 feet. A Small Craft Advisory is in effect for our coastal ocean zones that runs from 4 PM Saturday to 10 AM Sunday.

Outlook...

Monday...No marine hazards expected. Fair weather.

Tuesday through Wednesday...Southwest winds increase and could reach Small Craft Advisory levels by late Tuesday into Wednesday.

Rip Currents...

There is a MODERATE risk for the development of dangerous and life threatening rip currents for the Jersey Shore and Delware Beaches both Saturday and Sunday.

On Saturday, south winds will increase to 15 to 20 mph with 25 to 30 mph along with breaking waves of 2 to 3 feet with a 3 to 4 feet/9 to 10 period swell. There is still the potential for the rip current risk to be upgraded to HIGH.

On Sunday, winds shift to more of a west to southwest flow at 10 to 15 mph. There will continue to be breaking waves of 2 to 3 feet with a 3 to 4 feet/9 to 10 period swell.

Important to note that while surface temperatures inland will be in the low 80s on Saturday and in the upper 80s on Sunday, temperatures along the coasts will mainly be in the 70s due to ocean temperatures in the 50s. These cold water temperatures can quickly cause hypothermia and physical incapacitation to anyone suddenly immersed in the water.

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

PHI WATCHES/WARNINGS/ADVISORIES

PA...None. NJ...None. DE...None. MD...None. MARINE...Small Craft Advisory from 4 PM Saturday to 10 AM EDT Sunday for ANZ450>455.