Monthly Archives: August 2019

Severe Weather

Thunderstorm Outlook- Wednesday

The frontal passage and thunderstorms in Philadelphia expected today will be well-handled by the NWS.

So, what value-add can I offer this early in the day?

Reviewing the models from earlier this morning, the following characteristics and trends exist:

There’s a possibility of some earlier scattered showers and thunderstorms as early as 12-2PM.

Increasing  areal activity is expected between the hours of 4 PM and 8 PM.   A line of storms should develop by 5-6 PM and move through the Philadelphia area, according to the latest RAP and HRRR models.

The severe weather parameters (cape, helicity, shear, precipitable water) are all elevated, but not as elevated as seen a few weeks ago with the tornado development.

Some low pressure centers are expected to develop in this line of storms and additional activity may linger until after 8 PM.

Weather Updates

WEEKEND WEATHER UPDATE

[su_note note_color=”#d9f2da”]No showers developed Philadelphia and west, as expected. There were some thundershowers in south Jersey, not as much areal coverage as predicted by the models last night. Dew points were delightfully lower than had been predicted.  [/su_note]

Pop-up, widely scattered thundershowers did develop today (Saturday), but the areal coverage was hardly close to the model precipitation forecast graphics that I posted yesterday. (This morning’s models which came out after 10:45 am had actually cut back on the showers for today.)

Tonight’s model forecast just becoming available shows even fewer showers for the immediate Philadelphia area westward, but a weak frontal boundary passing through sparks some thundershowers, mostly from the city eastward into N.J. mid to late afternoon.

Current WRF 1hour accumulated rain forecast Sunday 4:30 pm

As we’ve seen today, prediction of specific areal location of thundershowers is something models attempt to do with limited and inconsistent success.

Except for these showers, Sunday will be mostly sunny, very warm and somewhat humid— typical August weather. High 87-89.