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Friday and the Weekend Outlook
Posted Thursday 05/14/26 @ 7:52 PM — As expected, the rather impressive line of showers Wednesday night fell apart as they approached an unfavorable upper air environment. Here’s the area rainfall—
The upper low pressure system over us will gradually depart and a weak warm front will approach later on Saturday. We may see some clouds on Saturday but rain will fall apart as it approaches our area!
Much warmer on Sunday and into next week!
Wednesday Forecast Update
Posted Wednesday 05/13/26 @ 7:37 AM —The latest RRFS (06z) shows the approaching showers today moving in as two separate lobes; the first one, scattered and light swings through about 6-7 PM.
The second more organized line of showers moves through between 8 PM and 11 PM. The second line of showers is expected to weaken, for the reasons described below as it moves eastward. Total rainfall still expected to be light, although the latest RRFS shows 0.40″; most models still in the 0.25″ or less range.
An upper air low with a pool of cold air aloft will bring variable cloudiness with a chance of scattered instability showers during the afternoon hours on Thursday. Not all areas will see showers.
So Little Rain. Why?
Posted Tuesday 05/12/26 @ 8:02 PM — In recent months, we haven’t seen much in the way of typical Springtime thunderstorms. Most of the time, we’ve been an an anticyclonic upper air flow (clockwise curvature) which produces descending air flow.
Wednesday is another example where a large area of rain somewhat diminishes in intensity as it approaches.
This is a good example of another reason- our position in relation to the position of the jet stream (and more specifically, the constricted part of the wind stream resulting in higher speeds called the ‘jet streak’)
Our position on Wednesday evening will put us in what’s called the Left Entrance Region of the nearby jet streak. This region has vertical descending flow which works against precipitation.
A textbook representation is here—
By the way, the jet in “jet stream” doesn’t get its name from being at the level that jet airplanes fly (34,000-38,000 feet).
The “jet” in jet stream refers to fluid dynamics terminology where constriction in flow causes an increase in velocity of flow. You’ve all seen a garden hose where the nozzle constricts flow causing a jet of water. Air is a fluid too. The upper air winds flow in the valley between air masses. Where that valley constricts causes the jet streaks.
Wednesday Forecast Update
Posted Tuesday 05/12/26 @ 5:46 PM —A cold front will approach and move through our area Wednesday evening. During the daytime hours, Wednesday will have mostly sunny skies through high cirrus clouds in the morning, then periods of clouds in the mid afternoon with the sun breaking out again about 4 PM. It will be windy and times.
Rain with this system will occur behind the front and wind shift. The wind shift occurs about 8 PM (Blue Bell) and the rain showers move in between 8 and 9 PM. Rainfall had originally looked to be impressive, now looks to be on the light side. Total rainfall about 0.20″ The rain is no longer expected to linger into Thursday.
An upper level low will linger over our area Thursday and Friday. A mix of sun and clouds is expected, but with an upper low in May, one can’t rule out a scattered shower.
For weather nerds—
The RRFS and REFS production implementation and the retirement of the legacy models will occur on the same day.“
Tuesday-Wednesday Outlook
Posted Monday 05/11/26 @ 8:05 PM — We’ll finally get some sunny skies on Tuesday, as high pressure builds in behind the system that exited on Monday.
Yet another dip in the jet along with a surface low over the Great Lakes will push a cold front slowly through on Wednesday.
The models continue to have some showers along this front linger into Thursday as the upper jet digs deeper towards the south. It look like this jet dip will have temperatures less chilly than the one with us on Monday.
Originally Posted Mon 9:40 AM —This week will be an active week weather-wise, as an atypical dip in the jet stream and cool air collides with May moisture and warmth from the south.
For today, the front that went through yesterday with the fast moving storms (we had some hail at the start) is still poised to bring some light rain to areas just east of I-95 today into the Jersey Shore.
Varying degrees of mid-level cloudiness is forecast for today but “mostly cloudy” captures it . There will be gradual clearing, perhaps about 5 PM, from the northwest. A few showers this evening are possible near Allentown as an upper air disturbance moves through.
Tuesday looks quite nice!
As for rainfall, here’s what the area received on Sunday evening/night. The rain was very localized- There were sharp gradients with areas receiving 0.25″ and a mile or so away, the totals were 0.75″—
