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Weekend Outlook

Posted Thursday 06/06/24 @ 7:44 PM —The forecast for Friday and the upcoming weekend is looking considerably brighter than it had been earlier this week.

Most of the clouds and showers associated with the upper low in Canada will stay well to our north. Plenty of sunshine with occasional clouds is expected, and temperatures will remain somewhat below seasonal averages.

Expect highs in the low 80s Friday through Sunday. Some clouds and light scattered showers may still occur during the afternoon Sunday.

Thu 7:21 AM —Forecast Review —Looking over the MRMS based rain totals this morning, it appears that the HRRR below did the best in forecasting the overall placement of the heavier rain last night. (The posted NAM-NEST had the axis of heavy rain too far into Philadelphia. Not posted last night was the 18z experimental RRFS, whose forecast had the heavy rain axis way too far south. )

As expected, many areas received only small to moderate rainfall, less than 1/2 inch.

Here’s the MRMS rainfall summery —

Thursday- Afternoon Shower/Thundershowers

Posted Thursday 06/06/24 @ 7:40 AM — An upper air disturbance will move through today, Thursday, between 2 PM and 6 PM from the northwest. Expect some showers and thunderstorms to move through at that time. Some gusty winds and quick moving heavy rain possible in some locations. Before that time, we may see some sunshine or sunhine though high clouds.

Heavy Rain Possible in Some Areas

Posted Wednesday 06/05/24 @ 4:38 PM — The models have come together with rain moving in from the southwest between 6 and 8 PM Wednesday evening. The models are forecasting areas of heavy rainfall in some areas; as always, they differ in the exact location.

Some of the rain will come in the form of thunderstorms. While some storms may be strong, severe weather doesn’t appear likely.

The following two images shows the difference in location between the latest HRRR and the latest NAM-NEST heavy rainfall forecasts—

Posted Wednesday 06/05/24 @ 7:41 AM — The question for today- when will the rain start in the Philadelphia area. My forecast yesterday, based on the Canadian models, had activity moving in as early as 1-3 PM. This rain is associated with a warm front.

Today, the Canadian models, along with a good many others, have a later start for the rain, between 6 PM and 8 PM. The GFS has some activity breaking out ahead of the main area of rain as early as 4 PM and the latest NBM also has some light activity as early as 4 PM. So quite a range!

Either way, the heavier showers and possibly thundershowers will be here between 6 and 8 PM and continue until at least midnight to 2 AM. The heaviest activity will be in southern Chester county and down near Wilmington DE.

On Thursday morning, a lull in activity, followed by additional rain by late morning into the afternoon.

Friday looks cloudy but dry now. Saturday looks pretty good, especially at the NJ shore.

Posted Tuesday 06/04/24 @ 4:50 PM — There’s been a shift towards an earlier start for the showers moving in on Wednesday. We’re back to an earlier start of about 1-3 PM moving in from the west-southwest. While the showers will be widely scattered at the start, expect the rain to fill in by late afternoon and early evening.

This morning’s Canadian RGEM had the best forecast for the showers south of us along the Chesapeake occurring right now. Here’s its forecast for 2 PM Wednesday—

Just an aside— while we’ve had plenty of rain showers over the past month, most of the rainfall in the immediate Philadelphia area and South Jersey has been on the light side in most areas. We haven’t had those 1-3 inch generalized rainfalls recently. Nor have we had any lines of heavy thunderstorms. A trajectory towards a drier summer??

Posted Tuesday 06/04/24 @ 9:08 AM — Tuesday should be sunny, warm and pleasant. Any instability showers late afternoon will be west of Lancaster and Reading.

Wednesday looks to be mostly cloudy. Some models have the showers from the next system moving in as early as 2-3 PM. A majority of models hold off the showers until the evening.

This past Sunday, it looked like the period between late Wednesday through this coming weekend would be stormy. Things have backed off and it appears that the word to describe this period would be “unsettled”, with much of the energy and heavy rain sliding off to our far northwest.

We’ll have to see how the upper low and the surface lows position themselves for a more definitive forecast for late Thursday into the weekend. A nicer weekend now looks possible with the showers staying far north for Friday and much of Saturday. Sunday maybe not.

Posted Monday 06/03/24 @ 9:48 AM — An upper air disturbance along with moisture and thermal instability will result in scattered showers and thundershowers today, Monday, after 4 PM. Most models have most of the showers from Philadelphia and southward, as shown by the latest model blend (NBM), although the latest GFS has some additional activity further north—

For Tuesday, sunny skies in the morning will have some clouds and sunshine through high clouds in the afternoon. Showers develop to our west Tuesday evening as the next weather pattern develops.

Beginning early afternoon Wednesday , our area comes under the influence of a slow moving upper trough and associated surface low pressure systems. Considerable rain, showers and thundershowers are likely, possibly into the weekend.

Originally Posted Sun 7:31 PM —Following a weak upper air disturbance that will move through late Monday afternoon and evening with widely scattered showers and some thunder (mostly affecting areas to our south and South Jersey), we’ll be moving into a somewhat blocked pattern with an upper trough dropping into the eastern US.

The trough will become entrenched by late Wednesday—

Showers and thunderstorms expected by Wednesday afternoon and unsettled weather through at least Friday.

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Rain-Free through Sunday

Posted Friday 05/31/24 @ 9:13 AM — The latest model runs have backed off on the light showers that had been expected to move in during the day on Sunday. It now appears that we’ll have gradually increasing clouds and any light showers, if any, won’t move in until early Sunday evening.

The latest ECMWF , which had been quite aggressive with the rainfall Sunday evening, has joined the latest GFS with little in the way of rainfall—

So a very nice weekend overall.

Saturday we’ll get into the low 80s (81-83º) and Sunday (82-84º) Due to the cloud cover, there’s a bit more uncertainty regarding high temps on Sunday.

Delightful through Saturday

Posted Thursday 05/30/24 @ 9:42 AM —The cold front moved through last night and unseasonably cool delightful weather will be with us through Saturday.

Current water vapor imagery shows the air mass over our area and the disturbances setting up to move in sometime Sunday—

The big question is the timing of the next system on Sunday. Current trends are for it to be cloudy with light showers possible in Philadelphia Sunday afternoon. The light showers may arrive at the shore later in the evening.

Gusty Showers/Thunderstorms Wed Evening

Posted Wednesday 05/29/24 @ 8:39 AM — A cold front associated with an upper and surface trough will move through this evening.

The models have come together with a time frame of 6-8 PM, earlier southwest Chester county, for showers and embedded thunderstorms to move through. Some locations will receive an inch of rain, while adjacent areas less than a quarter of an inch. So the heavier rain will be spotty and localized. The heaviest rain is expected northern Bucks county and north of Allentown, as well as north central NJ.

The experimental RRFS model didn’t do bad for last Sunday’s rainfall. Here’s the RRFS total rainfall forecast for this evening—

As mentioned yesterday, the storms will move in from the southwest with gusty winds, which appears to be the main potential hazard. Truly severe weather not expected.

Skies clear by daybreak Thursday.

The weekend had been looking fine, but the latest NAEFS shows a warm front with showers moving in on Sunday—

Showers later Wednesday Afternoon

Posted Tuesday 05/28/24 @ 7:44 PM — A surface and upper trough approaches Wednesday with an increase in clouds after noontime with with showers and maybe some thunder during the afternoon.

Western suburbs may see some showers as early as 1-2 PM, but many models hold off the showers until 4-6 PM closer to the city. Some models are showing gusty winds preceding the showers late afternoon.

Total rainfall looks to be light. Showers continue into early Thursday morning with rapid clearing by about 10 AM. Becoming windy.

Cooler and windy for Thursday afternoon.

Previously Posted Tue 12:20 PM —Sunday’s rains were not all that heavy or severe. Here’s the MRMS-based rainfall summary —

Following a system that may bring us some rain later Wednesday, a large, cool high pressure system will bring very nice weather possibly through the weekend—

Next week should see a return to much warmer temperatures.

Things have stabilized somewhat with my family medical situation, and I will continue posting thoughts and commentary about the current weather over the coming days. For the time being, postings won’t be as frequent or comprehensive as they have been in the recent past.

Weekend Looking Better

Posted Thursday, 05/23/24 @ 7:35 PM— Timing and position of various disturbances over the weekend continues to be in flux. The gist of this morning’s update still holds, but it would not surprise me if things change radically, either for better weather overall, or worse for Saturday and Sunday. Monday still looks rainy.

Additionally, the weather conditions will be highly location dependent. With a front that will stall to our south, distances of 30-50 miles east-west or north-south of Philadelphia can have very different weather at different times of the day both Saturday and Sunday.

Posted Thursday 05/23/24 @ 12:45 PM — The timing of various disturbances moving across the area will impact the sensible weather this weekend, at least through Sunday. A lingering frontal system will affect mostly South Jersey on Friday with showers. Philadelphia may see sun on Friday.

Another disturbance approaching on Saturday will result in scattered showers/thundershowers late Saturday into Saturday evening in Philadelphia. The Jersey Shore will likely be sunny through high clouds on Saturday. The showers move into NJ Saturday night.

Sunday looks quite nice both in Philadelphia and the shore. There may be some clouds at times at the shore.

Monday looks cloudy and rainy. The heaviest rain in the early morning, but lingering cloudiness and scattered showers for the rest of the day with heavier rain developing again during the evening.

Posted Wednesday 05/22/24 @ 4:18 PM — Recent model runs have accelerated the passage of the cold front. Originally expected to move through late Thursday, the latest models have showers, perhaps with some thunder, moving through Thursday morning. No major storms are expected. (There’s even a chance of some showers moving in this evening (Wednesday), especially western sections.

Showers may linger through Thursday afternoon and evening as the front slows down.

There’s much uncertainty in the weekend forecast. The Canadian global model has significant rain for us over the weekend. NOAA has been doing planned maintenance on their main server today, and I don’t have the latest NAEFS.

The weekend may be saved by the changes in timing of the next disturbances. It’s possible that shower activity will occur during the evening Saturday instead of the daytime hours. This especially true at the shore.

Sunday does still appear to have showers in the afternoon as does Monday.

Here’s the latest ECMWF forecast for 2 PM Monday—

Posted Tuesday 05/21/24 @ 3:57 PM — What’s really catching my interest over the past week is the extraordinarily high temperatures for May I’m seeing in Florida and Texas. Such severe high temperatures this early in the season is of great concern.

There is evidence that these severe temperatures will be in our area sooner rather than later this upcoming summer season.

Posted Tue, 05/21/24 @ 11:00 AM— The next notable weather events this week and the upcoming Memorial Day Weekend will be a cold front that moves through later Thursday afternoon/evening and stalls east-west, becoming a focal point for low pressure development.

First, Thursday’s cold front will have plenty of thermodynamic energy for thunderstorms, BUT a weak jet flow and a weak anticyclonic curvature to the upper air winds may limit the development of locally severe weather. Most models are consistent with the heaviest rain and storms to occur to our north and to our south (in Maryland), somewhat skipping the immediate Philadelphia area. Total rainfall in the immediate PHL area will also be limited to under 1/2 inch of rain, as currently forecast.

The Memorial Day Weekend weather outlook is looking less than stellar. The cold front will stall to our south and areas of low pressure are expected to bring several periods of rain/showers Saturday through Monday. It’s too early to time these rainy periods.

Here’s the latest NAEFS forecast for Saturday evening—

There’s still time for the weekend outlook to improve, but this is how it appears to be shaping up right now.

Previously Posted Sun 7:07 PM —

We finally have some sun and the first part of this upcoming week should feature sunshine and increasing temperatures.

The current water vapor image captures all the elements for this coming week’s weather—

Temperatures will likely get into the mid to upper 80s by Thursday.

Here’s the current NAEFS forecast for Thursday afternoon. A cold front will move through, likely with thunderstorms, and the front may stall east west to our south. —

The upcoming Memorial Day Weekend is likely to start reasonably nice (but cool) but with an increasing chance of showers and clouds from maybe Sunday and more likely into Monday. Much uncertainty, but this is how things look now.