11:50 AM | *Strong coastal storm to form aided by a powerful upper-level jet streak…soaking rain, damaging winds for Mid-Atlantic/NE US*
Paul Dorian
Very strong winds aloft will aid in the development of a strong coastal storm later today and tonight in the Mid-Atlantic/NE US; map courtesy NOAA, tropicaltidbits.com
Overview
A vigorous upper-level low is dropping southeastward across the Great Lakes today and will interact with a powerful jet streak over the Tennessee Valley to help set off the formation of a strong coastal storm. This low will intensify this afternoon and tonight and will bring a soaking rainfall to the Mid-Atlantic region and the Northeast US – the likes of which haven’t been seen in many weeks. Winds will become an increasing problem as well and could gust past 50 mph later tonight and on Thursday in the Mid-Atlantic/NE US following the departure of the strong storm and possibly to hurricane force along coastal regions of southern New England. As some colder air wraps into the system on Thursday, there is a threat for a changeover to snow in some of the higher elevations of northern New York and New England.
The latest radar loop shows a solid area of rainfall pushing northeast up along the I-95 corridor. In addition, there is a “line” developing across western PA/West Virginia that could result in some embedded thunderstorm activity later in the day. Courtesy NOAA, College of DuPage
Details
A powerful jet streak over the Tennessee Valley is going to contribute to rapid intensification of a coastal low later today near the Mid-Atlantic coastline. In fact, a radiosonde balloon recorded a wind speed at 250 millibars this morning over Nashville, Tennessee and this may be an all-time high for the month of October. As this jet streak pushes to the northeast, it’ll combine with a “negatively-tilted” upper level low (i.e., trough axis oriented from NW to SE) to intensify a developing surface low pressure system near the Mid-Atlantic coastline. Rain has already pushed into the DC metro region and is on the doorstep in Philly and it will continue to spread to the northeast over the next few hours up along the I-95 corridor. Latest radar echoes are also showing the makings of a “line” out across western PA/West Virginia and this could result in some embedded thunder late in the day or early tonight in the I-95 corridor. Rainfall amounts are likely to increase from this storm as one moves to the northeast in the I-95 corridor with total amounts likely near an inch in DC, an inch and a half in Philly, and 2+ inches are possible in NYC and Boston.
Wide satellite view of the developing strong coastal storm; courtesy NOAA, College of DuPage
Winds will become an increasing issue in the Mid-Atlantic and NE US as the storm intensifies over the next 12-24 hours and power outages are certainly on the table. In fact, winds can gust to 50 mph in the I-95 corridor late tonight and on Thursday following the departure of the storm system. As colder air wraps into the system on Thursday, the rain can change to snow in northern New York and New England with small accumulations on the table. In addition to the winds, it’ll be quite cool on Thursday behind the storm with temperatures likely holding in the 50;’s in most areas of the Mid-Atlantic and NE US. It turns somewhat quieter on Friday, but there will still be a breeze and the cool conditions will continue.
Meteorologist Paul Dorian
Perspecta, Inc.
perspectaweather.com
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