12:40 PM | *Squall line update and "black ice" potential by dawn*
Paul Dorian
12:13 PM radar showing squall line (circled region); courtesy NOAA
Squall line update
An impressive squall line on radar is closing in on Philly, southern NJ and it will generate very heavy rain, potentially damaging wind gusts to 60 mph, and perhaps a rumble of thunder over the next 30-60 minutes. This line is moving extremely rapidly to the northeast at around 75 mph. The squall line should reach the NYC metro region shortly after 2PM.
Black ice threat
The following combination could very well produce “black ice” late tonight/early tomorrow in the I-95 corridor; primarily, in the northern and western suburbs of Philly, NYC and just in time for the morning commute:
1) temperatures drop to near freezing late tonight,
2) many surfaces will remain moist in the overnight hours following today’s heavy rain as it will not be a classic “drying” pattern following the passage of a frontal system,
3) heavy rain from today washes away the “protective” salt on the roads
4) finally, there are still some isolated patches of snow/ice that will continue to melt away.
Meteorologist Paul Dorian
Vencore, Inc.