11:40 AM (Thurs) | ***Winter storm threat continues for early next week in the Mid-Atlantic…second threat comes later in the week…”snow drought” for DC, Philly, NYC likely coming to a decisive end***
Paul Dorian
Two strong waves of energy in the upper atmosphere will spawn low pressure systems that threaten the Mid-Atlantic region with wintry precipitation from later Monday into Tuesday and then again later Wednesday into Thursday. Map courtesy WSI, Inc., ECMWF
Overview
Philadelphia and New York City received traces of snow early yesterday as an upper-level wave of energy passed overhead, but there has not been anything significant in terms of snow in these two metro regions - nor in the Washington, D.C. area - since the middle of December. This “snow drought” in the DC-to-Philly-to-NYC corridor may come to a rather dramatic end over the next ten days or so. One winter storm can impact the Mid-Atlantic region from later Monday into Tuesday and then a second threat exists for later next week. There have been numerous threats of snow in recent weeks for the I-95 corridor and all have fizzled out, but there is perhaps better cause for optimism this time around for snow lovers in the I-95 corridor.
Total snowfall for the next 15 days as depicted by the 00Z Euro ensemble run with 6+ inches (purple hue) in much of the Mid-Atlantic region. Map courtesy Weather Bell Analytics, ECMWF
Details
A storm in the middle of December brought accumulating snow to much of the I-95 corridor from DC-to-Philly-to-NYC with 2+ inches on the western side of the District of Columbia, 6+ inches in the Philly metro region, and 9+ inches to the NYC metro area. Since then, however, multiple snow threats have fizzled out and the immediate I-95 corridor has been in a relative “snow drought” for several weeks. In Philly and New York City only “traces” of snow have been recorded during the entire month of January and there has been no snow at all recorded this month at Reagan National Airport (DCA) in Washington, D.C. Multiple “longer-range” storm threats in the second half of December and also during the first half of January have either resulted in low pressure systems staying to the south of the Mid-Atlantic region or have seen these storms weaken significantly by the time they reached the eastern states.
12Z GFS surface forecast map as of 7PM, Monday, January 25th. Map courtesy NOAA, tropicaltidbits.com
The next cold front in a series of frontal systems will cross the Mid-Atlantic region by early Friday and its passage will usher in quite a cold air mass for the upcoming weekend with daily highs confined to the 30’s in DC, Philly and New York City. Low pressure is likely to pull out of the south-central states on Monday morning, cross over the Tennessee Valley, and then heads towards the Mid-Atlantic coastline by early Tuesday. There will be enough entrenched cold air around to allow for snow and/or ice north of the PA/MD border at the onset of this event early next week and even in areas to the south of the Mason-Dixon Line such as the Washington, D.C. metro region, frozen precipitation will be a possibility at the start. As the low pressure system pushes to near the Mid-Atlantic coastline (and to the south and east of I-95), colder air will drop southward and any mixed precipitation or plain rain that falls early in this event in the DC metro region could change to all snow during the latter stages of the winter storm. Snow accumulations are on the table from later Monday into Tuesday; especially, in those areas north of the PA/MD border. The upper-level energy likely to spin off this low pressure system is still out over the Pacific Ocean so it’ll be a few days before it even reaches the western US where better data observations are available allowing for additional details to be ironed out.
A second storm could threaten the Mid-Atlantic region with snow by next Wednesday night and Thursday. Map courtesy NOAA, tropcialtidbits.com
The on-going active weather pattern is likely to feature another strong wave of energy by the middle of next week pushing into the western US from the Pacific Ocean. This second system which is currently far out over the Pacific Ocean should follow rather closely on the heels of the early week system. Low pressure may cross the central Plains at mid-week and it could impact the Mid-Atlantic region by Wednesday night or Thursday. This second “longer-range” threat to the Mid-Atlantic region will likely have sustained cold air to work with as strong high pressure will be located to the north in southeastern Canada anchoring the air mass in place. It is, however, still somewhat uncertain as to how far north and east this late week system will come and there are many days to determine the ultimate storm track and intensity, but odds would favor primarily snow in the DC-to-Philly-to-NYC corridor.
The bottom line, there is a quite a good chance of accumulating snow in the DC-to-Philly-to-NYC corridor over the next ten days or so, but the all-important details will need more time to be ironed out….stay tuned.
Meteorologist Paul Dorian
Perspecta, Inc.
perspectaweather.com
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