7/21 Weather Brief

• Cold front approaches, chance of thunderstorms
• Model guidance suggests storms blooming around 2 PM in SEPA
• Gusty winds and hail are greatest threats
• Temps in the mid-80s

Currently we have low pressure and cold front to our north and west.

Lots of haziness around still and the smokey skies are causing air quality issues. Plenty of orange and red areas of AQI. Sensitive groups may have difficulty breathing and it is recommended to limit time outdoors. Air quality should improve tomorrow.

High temperatures today should be around 86 or so for Philly

The story today is the chance for severe weather. The best chance is east of Philly, but strong storms can’t be ruled out for the city.

Models differ on timing and strength of thunderstorms. Pictured below is the NAM, which has storms in SEPA and SNJ in the early afternoon

However, the FV3 hi-res model (GFS) disagrees and suggests storms further north

Ensembles suggest storms around 2PM to bubble in EPA and push into NJ and LI.

So a little bit of a mystery day today with where the storms will be strongest. Generally it appears that instability will be uniform in the high risk areas, but possibly greater to the south in the early afternoon. The mid-level/upper level orientation suggests that northern areas will receive better support for storm formation. So there is a little bit of favorability for both areas.

As always, thank you for reading and stay weather aware today