12:30 PM (Tuesday) | ****A wild ten days of weather****

Snow will dominate the scene across the DC-to-Philly-to-NYC corridor by the time we get to the evening hours as low pressure heads to the open waters of the western Atlantic Ocean. Map courtesy NOAA, tropicaltidbits.com

Overview

The hits just keep on coming and it looks like a wild ten days of weather...

The very active weather patten will bring the Mid-Atlantic region a snow event later today/tonight...a mixed precipitation event later tomorrow/tomorrow night...a weekend double-barreled strong storm system with gusty winds, rain that can get heavy at times, and snow cannot be ruled out on the front end...and, finally, there can be an east coast storm threat later next week.

The mid-day radar loop features snow in the southern Mid-Atlantic region (shown in blue) and rain in areas to the south and west (shown in green). Radar loop courtesy WSI Intellicast, Weather Underground, NOAA

Accumulating snow event later today into early Wednesday

Snow will develop during the early afternoon hours across the DC metro region, late afternoon in Philly, and early evening across NYC. Today’s low pressure system will take more of a southern route compared to recent systems and likely reach the coastal waters off of Virginia/North Carolina by the wee hours of Wednesday morning. As such, cold air is better established across the Mid-Atlantic region ahead of the incoming system, and this will result in primarily - if not completely - a snow event in the DC-to-Philly-to-NYC corridor. Given this southern track, this system is likely to produce the highest snowfall amounts across the southern Mid-Atlantic region in such places as Washington, D.C., Virginia, Delmarva Peninsula, and southern New Jersey and lesser amounts are expected across New York City and northeastern PA.

Breakdown of starting times, snowfall estimates for DC, Philly, NYC:

DC: Snow begins during the early afternoon hours and can come down hard by early evening. Snow winds down late tonight with final accumulations on the order of 4-7 inches along with isolated higher amounts.

Philly:  Snow begins during the late afternoon hours and can come down hard by later in the evening. Snow winds down early Wednesday with accumulations on the order of 2-5 inches (higher amounts in that range to the south and lower amounts to the north, e.g., southern Chester County should get more on average compared to northern Montgomery County).

NYC:  Snow begins during the early evening hours and continues into early Wednesday with snowfall amounts on the order of 1-3 inches.

Next winter storm quickly follows...later tomorrow into Thursday

The next in a long series of low pressure systems in this on-going active weather pattern will bring more precipitation to the Mid-Atlantic region as quickly as later tomorrow and - with high pressure parked over southeastern Canada - cold air will be reluctant to give up its ground across the northeastern states...at least for awhile. As a result, there can be some snow and/or sleet for awhile tomorrow and then freezing rain will be possible late in the day and tomorrow night; especially, in the normally colder suburban locations to the north and west of the big cities in the I-95 corridor. Temperatures should climb well above freezing on Thursday so any leftover precipitation should be in the form of plain rain.  

A strong double-barreled storm system is likely to impact the Mid-Atlantic region this weekend and it may feature some heavy rainfall and gusty winds. In fact, the front end of the weekend storm might be cold enough for some snow on Saturday and, as cold air pours in following a cold frontal passage, there can be snow shower activity on the back end (later Sunday). Maps courtesy NOAA, tropicaltidbits.com.

Weekend double-barreled storm system

A strong double-barreled storm system will work its way into the northeastern part of the nation this weekend and can impact the weather from Saturday into Sunday. An initial system may bring some snow to the region on Saturday before enough warming occurs for the precipitation to become plain rain likely by Saturday night. The second part of this system will become quite strong as it slides to the northwest of I-95 and it can produce some heavy rainfall at times…maybe even a thunderstorm. This second system will drag a strong cold front through the Mid-Atlantic later Sunday and cold air will pour in on its backside. There is the chance that as the cold air rushes in the precipitation may end as some snow shower activity. Winds will become a noticeable factor as well with this Sunday system (second part of the double-barrel) likely from the south-to-southwest ahead of the cold front and then from a northwesterly direction later Sunday/Sunday night following the passage of the front.

The MJO is predicted to push through phases 8 and 1 during the second half of the month and these are typically correlated with quite cold conditions across the central and eastern states. Plot courtesy ECMWF, NOAA

Cold outlook for next week...possible east coast threat by the 20th or so

Following the passage of the strong cold front later Sunday, cold air looks like it will flood the northeastern states and next week looks to be quite a bit colder-than-normal on average across the central and eastern US. This notion of colder-than-normal weather next week is supported by the movement of a tropical disturbance that is tracked around the globe by meteorologists using an index known as the Madden-Julian Oscillation or MJO. Depending on its location (or “phase”) for the given time of year, it can provide clues as to temperature patterns across the nation. At this stage of the winter season, when the MJO moves into phases 8 and 1, temperatures are typically below-normal across the central and eastern states. Indeed, it appears the MJO will push through phase 8 during the period from February 15th to February 21st and then into phase 1 around February 22nd or so...both of these phases suggest colder-than-normal temperatures across much of central and eastern US.

The location or “phase” of the tropical disturbance known as the MJO can play an important role in temperature patterns across the US. During this stage of the winter season, “phases” 8 and 1 usually result in colder-than-normal weather across the central and eastern states (see boxed in temperature composite maps). Maps courtesy NOAA

By the middle of the week, a strong upper-level low may push from the southwestern states into the south-central US, and this could help to produce a strong storm system near the eastern seaboard during the latter part of next week...perhaps right around Thursday, February 20th.  And with plenty of cold air out ahead of it across the northeastern states, this is certainly a system that would have to be closely monitored in coming days...stay tuned.

Meteorologist Paul Dorian
Arcfield
arcfieldweather.com

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