[su_note note_color=”#d9f2da”]Tues 10 AM Update: This morning’s RAP (Rapid Refresh) model has thunderstorms breaking out 3-4 PM around Philadelphia and continuing on and off until 8-9 PM. Over past weeks, the morning RAP model has had a fairly good track record. [/su_note]

from earlier Tues morning:

[su_note note_color=”#d9f2da”]Tues 8 AM Update: Last night’s models have backed away from the severe weather in the immediate PHL area. The severe parameters (Helicity, Vertical Shear) have reduced from yesterday’s model runs; the expected lack of sunshine will reduce the chance of severe weather in our immediate neck of the woods.

One can still expect showers and thunderstorms to develop as early as noon and continue into the afternoon. Some of the rainfall may still be locally heavy in spots. It may be very windy in some thunderstorms.

As mentioned yesterday, the heavier dynamics now appear to develop to our south and east. [/su_note]

from yesterday…

Tuesday has been in the crosshairs for severe weather for several days.  The bullseye for the severe weather had been the immediate Philadelphia area, but the latest models show that the most extreme aspects looks to occur to the south of us, near the Washington DC area.

That said, there are plenty of ingredients that are poised to come together in our area.

A warm front will pass through Tuesday morning, possibly causing showers and thunderstorms before daybreak with another possibility around noon.  A cold front associated with a low pressure system moves through during the late afternoon and early evening hours.

Thunderstorms with heavy rain and high winds are possible both during the afternoon and early evening.  Some of the severe weather parameters (helicity, vertical shear) are highly elevated giving us a  risk of high winds and slight risk of tornados.  Luckily, we may not have that much sunshine, limiting the available energy and reducing the potential for very extreme weather.

The models are still evolving and have changed their forecast considerably over the past 24 hours.  The NWS does a great job with these events and it’s suggested to stay tuned to their forecasts.