Updated Sun 11:22 PM — Tonight’s models show thunderstorms of greater intensity as the front moves into New Jersey early afternoon.
Update Sun @ 7:38 PM — Most models show the timing of the front as described below. But, the latest RAP model and GFS have the main wave of the front moving through much earlier. The GFS has showers starting as early as 10-11 AM and the RAP as early as 8-10 AM.
Update Sun @ 5:44 PM — A cold front will move through our area Monday morning through early afternoon with showers and thunderstorms.
The front is likely to come through in two waves— an early period 6-8 AM with very widely scattered showers and storms. Another wave approaches about noon to 2 PM with a more distinct line of showers and thunderstorms. No severe storms expected here. Heavy rainfall (1-1.5 inches) in some locales will be the main impact.
Since the front is coming through early, daytime heating effects will be minimized. This will reduce the likelihood of any severe weather. The energy with this front is distributed in two waves, also reducing severity. Possibly stronger storms will be nearer the Jersey shore and southward into Delaware.
Updated Sat 10:35 PM — Current Sunday forecast looks good. High temps 90-92°, dew points low 60s. The approaching cold front won’t affect us until Monday morning.
Showers and thundershowers Monday morning and early afternoon with the cold front likely will not be severe in our area. Some areas of heavy rain possible.
The upper air low pressure system will finally move out allowing high pressure and an upper air ridge to move in bringing much warmer conditions, above seasonable average temperatures. (average highs are 83º Blue Bell and 85º Philadelphia)
Sunny and compared to recent conditions, very warm. Borderline humid with dew points in the mid 60s. High temperature 88.7º ± 2.0º NBM model, Blue Bell PA. There’s a chance of very widely scattered pop-up thundershowers, mostly far northwest of the city during the afternoon.
Sunny and somewhat warmer. Lower dew points in the low 60s. High temperature 90.5º ± 3.5º NBM model, Blue Bell PA.
A cold front moves in late Sunday evening and overnight with showers and thunderstorms into Monday morning.
Updated Sat 7:48 PM — Sunday will be sunny. Still very windy. Wind gusts 30-40 mph. High temp 73.4º ± 1.5º NBM model Blue Bell. (Average seasonal high this time of year is 83-84°)
Update Sat @ 10:25 AM —
Forecast Review— Despite the lack of most models’ support, instability cloudiness did develop during Saturday morning. Why the models don’t seem to forecast this very well is a mystery to me, but I’ve seen it happen many times in similar setups.
Increasing sunny breaks and sunshine should begin during the afternoon; I’m basing this on the ICON and ECMWF models which did show this cloudiness.
Updated Fri 11:06 PM — Tonight’s models have backed away from the Saturday morning cloudiness.
Update Fri @ 5:59 PM — Forecast Updated in below
High pressure builds in behind a cold front Friday. We’ll be under the influence of high pressure at the surface and low pressure aloft—
From this upper wind configuration, expect cooler temperatures, windy conditions and possibly some cloudiness (although the models aren’t forecasting any clouds here right now.)
More specific forecast info later today…
Here’s the Fri 5:59 PM update on the forecast specifics:
As mentioned, the above upper air setup often leads to some cloudiness. Earlier models didn’t show it, but this afternoon’s GFS, ICON and ECMWF show upper air disturbances moving through around the upper low pressure system.
Saturday will be a mix of clouds and sun. The GFS is suggesting some significant periods of instability stratocumulus both in the morning and mid day, with fair weather cumulus along with periods of sunshine other times. Somewhat windy! High temperature 70.8º ± 2.6º NBM model, Blue Bell
Mostly sunny and delightful. High temp 75.0º ± 2.5º NBM model Blue Bell.