7:00 AM | ***Major rain event from tomorrow into early Friday...first freeze likely late Friday night...a cold Halloween***

6-Day forecast for the Philadelphia, PA metro region

Today

Mainly cloudy today with occasional light rain and drizzle in the morning, some brightening is possible in the afternoon, mild, highs in the lower 60's

Tonight

Mainly cloudy, chilly, chance of rain late, lows in the upper 40’s

Thursday

Mainly cloudy, quite chilly, breezy, periods of rain, some of the rain will be heavy at times, watch for localized flooding, lower 50’s for afternoon highs

Thursday Night

Mainly cloudy, colder late, breezy, periods of rain, some of the rain will be heavy at times, watch for localized flooding, lower 40’s for late night lows

Friday

Cold with mainly cloudy skies, continued threat of rain in the morning, an outside chance that some snowflakes mix in before the precipitation ends, mid-to-upper 40’s; first freeze of the season at night with lows in the upper 20's

Saturday

Patchy frost early then mainly sunny, quite chilly for Halloween Day, upper 40’s

Sunday

Partly sunny, not as cool, chance of showers, near 55 degrees

Monday

Mainly sunny, colder, upper 40's

Discussion

After landfall later today, the remains of “Zeta” will turn northeast and combine with a strong upper-level low to generate a powerful storm system and a significant rain event is coming to the Mid-Atlantic region from tomorrow into early Friday. By late tomorrow night, this powerful storm will likely be situated off the Mid-Atlantic coastline and a cold air mass will begin to get wrapped in. As a result, there is a good chance that some of the higher elevation, interior sections of the Northeast US (e.g., Poconos, Catskills, Hudson Valley) experience a changeover from rain to snow with accumulations certainly on the table. Following the departure of the storm, it’ll turn quite cold on Friday night with the first freeze of the season likely and low temperatures in the upper 20's. If, in fact, Saturday does bring the first freeze of the season, it’ll actually mark the shortest growing season in some spots since 2002 at 174 days between freezes. On Saturday, temperatures could very well average out to be some fifteen degrees below-normal making for quite a cold time of it for trick-or-treaters as we end the month of October. One final note, this is the weekend to turn the clocks back as of early Sunday morning, November 1st.

Meteorologist Paul Dorian
Perspecta, Inc.
perspectaweather.com