1:45 PM | ***The latest on the increasing likelihood of an intense ocean storm at week’s end...impact in Mid-Atlantic region still to be determined***

A powerful ocean storm is depicted here for Saturday evening, January 29th, by the latest Canadian computer forecast model run. Map courtesy Canadian Met Centre, tropicaltidbits.com

Overview

A cold and active weather pattern will continue this week across the eastern US and there is continued potential for an intense ocean storm at week’s end.  Many ingredients are likely to come together at the end of the week that will allow for explosive intensification of surface low pressure somewhere off the US east coast. These ingredients include the following: strong jet streaks in the northern and southern branches of the jet stream, plenty of very cold air to the north and west, relatively warm waters in the western Atlantic, and deepening low pressure aloft that will at some point take on a “negative” tilt in its axis orientation. It is still a bit too early to determine the ultimate storm track and exactly when the explosive intensification will take place, but all residents in the Mid-Atlantic/Northeast US should continue to closely monitor this unfolding intense ocean storm scenario.

The timing and location of the “phasing” together of two waves of energy in the upper atmosphere will largely dictate where the ocean storm ultimately tracks and how rapidly it will intensify. Map courtesy NOAA, tropicaltidbits.com

Details

After a slightly milder day in the Mid-Atlantic region, an Arctic blast will arrive in the overnight hours resulting in a mid-week deep freeze with low temperatures by early Thursday morning likely not too far from the 10 degree mark in the DC-to-Philly-to-NYC corridor.  In fact, it is likely to be cold enough across places like upstate Pennsylvania for many sub-zero readings as we begin the day on Thursday.  At this point in time, all eyes will change focus from the mid-week Arctic cold blast to the formation of low pressure near the eastern seaboard at week’s end.

Very cold air will be feeing into this system by the weekend pushing into the eastern states from the west and north. Map courtesy NOAA, tropicaltidbits.com

By the end of the week, many ingredients will likely come together for the formation of low pressure near or just off the southeastern US coastline and then an explosive intensification as it begins a move to the northeast.  One key ingredient will be an upper-low that will deepen as it becomes increasingly influenced by the phasing together of two waves of energy…one riding along in the northern stream of the upper-air wind flow and the other in the southern branch.  These two systems will indeed “phase” together at some point generating explosive intensification in surface low pressure positioned somewhere off the eastern seaboard. 

The 12Z Euro model run features a powerful upper-level low sitting over the Tennessee Valley region as of late Friday night. In this position, “phasing” will take place at a time and location that potentially increases impact significantly in the eastern Mid-Atlantic region (e.g., southeastern PA, New Jersey, Delmarva Peninsula). Map courtesy ECMWF, Pivotal Weather

Other factors that will play a role in the late week/early weekend scenario will include a very cold air mass pushing into the eastern states from the north and west and the relatively warm waters of the western Atlantic Ocean. This combination will set up a tight temperature gradient at the coast (i.e., cold land temperatures to the west…relatively warm waters to the east) and this will aid in the intensification of surface low pressure and also play a role in its ultimate path. 

Sea surface temperatures are generally above-normal in the western Atlantic and this will set up a tight temperature gradient along the east coast with very cold air over the land mass to the west. Map courtesy NOAA, tropcialtidbits.com

One of the issues that needs to be ironed out over the next couple of days is how quick the “phasing” together of the upper-level systems can take place. This will not only be critical to the timing of the rapid intensification, but also be a crucial factor in the storm track as well.  A quicker “phase” (e.g., 12Z Euro) would allow for a storm track to be closer-in to the east coast resulting in a bigger impact on the eastern Mid-Atlantic region (e.g., SE PA, NJ, Delmarva) and a slower “phase” would push some of the biggest impacts off to the northeast (e.g., NYC, New England). At this vantage point, all residents in the Mid-Atlantic and Northeast US should continue to closely monitor this unfolding situation in which the development of an intense ocean storm with wide-ranging impacts is looking increasingly likely.

Meteorologist Paul Dorian
Arcfield
arcfieldweather.com

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