Category Archives: PHL Climate Forecasts

Philadelphia Area Weather Forecasts, PHL Climate Forecasts

WEEKEND WEATHER FORECAST

#Philadelphia #weather #PAwx #PhillyWx

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.)


Commentary, PHL Climate Forecasts

Climate Outlook

#Philadelphia #weather #PAwx #PhillyWx

Observation-based Climate Outlook

I wanted to share with you my climate outlook for Philadelphia for the spring and summer.

I’ve noticed over the past winter a drought-leaning storm track trend that really had its origin last spring 2025. This trend has manifest itself multiple times over the the winter and this past month. Basically, the heaviest precipitation with multiple storms has stayed well north and west of the immediate Philadelphia area and adjacent South Jersey.

Sure, we had a big snow storm, but the total water equivalent was not more than 2″. We had several weeks where the old saying ” it’s too cold to snow” seemed to be spot-on. This past winter has left us with a precipitation deficit.

Recently, multiple rounds of multi-day cloudiness with showers has yielded low precipitation amounts of less than 1/3 of an inch. Really not enough rainfall. It wasn’t too many years ago that routine storms with multi-inch rainfall was common. It’s been a while since we had those. Last year, I focused on the observation that thunderstorms seemed to move to the far north and the far south of Philadelphia area and would dissipate as they moved into the city.

They say that “April showers bring May Flowers”. Unfortunately, I don’t seem much rainfall in the medium range models for us. The best example is next week, where the entire pattern will be dry for us.

AIGFS forecast for next Monday. There’s a large Bermuda high that’s beginning to take shape in the western Atlantic and a storm track that is well into Canada. Our cool weather of this week will transition to much above-average temperatures next week with little chance of rainfall. (Click on image for a larger view.)

With recent warning of a “super-El Niño” developing, I’m expecting climate change to make a rather disturbing statement with an extremely hot and a very dry spring and summer for the Philadelphia region.

Climate forecasting is not my hobby nor it is my main focus or interest. But every so often, the bigger trends regarding weather and climate work their way into my attention.

Long time visitors to this blog know that I’ve attributed past dry and hot patterns to the phase of the 11 year sunspot cycle and an acknowledged 22 year solar sunspot pattern also documented in the climate literature. But frankly, I’m not sure what causes these climate patterns.

But I can’t ignore an unsettling trend that’s been unfolding on the weather maps over the past year. And I thought I’d share my observations. Let’s hope I’m wrong and we have a ‘normal’ summer when it comes to heat and precipitation.

PHL Climate Forecasts

WINTER 2022-2023 SNOW OUTLOOK

I’m often asked around this time of year whether we’ll get a lot of snow in the coming winter. My response over the past two to three winters has been that I don’t see any pattern evolving that would give us a greater likelihood for large snowfalls.

All I would say is that large temperature swings would be something to expect. The last three winters have been light on large snowfalls with large swings in temperatures every few weeks.

The large swings in temperature are likely to continue this winter.

In years where I see a pattern evolving, I usually wait until the first week of December to make the call. But this year, I’m chiming in early.

Let me cut to the chase— The jet pattern I’ve seen develop over the past month hasn’t been seen in several past winters. If it continues, it translates into more frequent coastal storm development with higher snowfall amounts this winter for our area.

The jet stream pattern forecast for this weekend captures the setup—

NAEFS forecast jet stream (250 mb winds) for Saturday. Plunging jet stream in central Canada with strong southern stream jet flow converging. This is a very different setup than we saw much of last winter where the plunge of cold air was much further into eastern Canada.

Climate forecasts are tough and even the experts at the NWS Climate Center have not always done well. Climate forecasts and weather forecasts, while they may appear on the surface to somewhat similar, are very different sciences. Climatologists even have their own models.

I’m more knowledgeable about weather compared to climate, but I’ve been looking at the maps these past few weeks and I wanted to share what I see in them a bit earlier in the season than usual.

While I’m at it, we need to keep an eye on Thanksgiving weekend, especially next Friday night into Saturday. Our first taste of either light snow or a mix is possible.