Philadelphia Area Weather Forecasts, PHL Climate Forecasts

WEEKEND WEATHER FORECAST

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Rain Outlook?

Posted Saturday 04/11/26 @ 9:11 AM — You’ve already heard what a nice weekend we’ll be having. What can I add?

Well, as mentioned over the past week or so, I’m seeing a pattern of very dry weather for our area over the coming months.

The latest ECMWF-AI will be used to illustrate and the pertinent information is in caption below —

06z ECMWF-AI forecast for Thursday. The shading shows the Total precipitation through 2AM Thursday. The path of the rain (green arrows) follow a path that takes it around our area, not through our area.

Notice the contour (faint gold color) that extends and pushes in to our area. That contour is a 500-1000mb “thickness” line— it captures the 3-D shape of the air mass over us in the lower half of the atmosphere. . Most important is the sharp anticyclonic curvature of the line right over us. This anticyclonic curvature is associated with downward motion; rain/showers that move towards this area will fall apart. (Click on image for a larger view.)

Continuing from the caption above, as long as this sharp, anticyclonic curvature remains over our area, rain and thunderstorms will be inhibited. We’ve seen this exact same process in recent past summers during what became drought situations. The best we’ll see with this setup are thunderstorms that fall apart as they approach and rain areas that become very light and scattered.

This pattern of rain ‘avoiding’ our area has been happening for quite awhile. These patterns certainly can change. If it’s part of a recognized climate pattern called the Madden-Julian Oscillation, it could easily last 3 months or more. I’m not liking what I’m seeing.

Weekend Early Edition – Beautiful Weekend

Originally Posted Fri 9:57 AM —A weak front, currently just northwest of Pennsylvania, will pass through about 5 AM Saturday morning. The rain associated with this front will shear off to our northwest. A few very light showers possible northwest of the city around midnight with this front. A negligible amount of rainfall.

Current satellite water vapor image with superimposed RAP model 500-1000 mb thickness lines (yellow), Mean Sea Level Pressure isobars (black contours) and radar. (Water Vapor Imagery reveals emitted water vapor infrared TEMPERATURE, NOT REFLECTED LIGHT from CLOUDS.) (Click on image for a larger view.)

High pressure builds in behind the front this weekend. Windy Saturday morning, then winds subside in the afternoon. Sunny with very light winds on Sunday. Highs 64º-68º Saturday and 69º-70º on Sunday. :

Another system comes through Monday. Rainfall again will stay far north and west of the city and South Jersey. We may see some scattered very light showers close to the city.

As I discussed last week, I see signs of a very dry pattern for our area in the extended range forecasts.

One more thing…

With a very dry pattern developing, I expect to see increasingly frequent wildfires forming with smoke issues affecting many areas in the coming months. Here’s the current HRRR smoke model showing wildfires and sources of smoke in the continental US—

12z HRRR smoke model shows sources of smoke- wildfires, other sources. (Click on image for a larger view.)