11:30 AM | ***Active pattern continues...double-barrel weekend storm system with snow or ice possible on the front end...rain to follow...possibly heavy...east coast storm threat later next week***

The MJO is predicted to push through phases 8 and 1 during the second half of the month and these are typically correlated with colder-than-normal conditions across the central and eastern states which may last all the way into the month of March. Plot courtesy ECMWF, NOAA

Overview

One low pressure system is pulling away this morning and another one is following right on its heels and will end up over the eastern Great Lakes by early Thursday. There will be some snow shower activity in the Mid-Atlantic region during the next several hours and then (light) mixed precipitation late today/early tonight should change to plain rain by late tonight/early tomorrow. Another storm system will hit the Mid-Atlantic region during the weekend and it’ll have an impact on both Saturday and Saturday. At the front end, there can be a burst of snow and/or sleet later Saturday morning or mid-day...perhaps even some accumulations north of the PA/MD border...and then rain is likely on Saturday night and Sunday. In fact, some of the rain can be heavy at times which would raise some flooding concerns given the combination of the rain with melting snow. A strong cold front pushes through the Mid-Atlantic later Sunday ushering in much colder-than-normal air mass for the first half of next week. By the middle of next week, we’ll have to watch for the possibility of an east coast storm system that would have plenty of cold air to work with in the Mid-Atlantic region.

Today, tonight and tomorrow

The low pressure system that brough snow to the Mid-Atlantic region late yesterday and last night is already positioned well to the east of here out over the open waters of the western Atlantic Ocean. Snowfall totals in the I-95 corridor as of early today are as follows: 6.4” at DCA, 4.9” at IAD, 3.1” at PHL, and 1.5” at Central Park in New York City. (By the way, the total snowfall at DCA is now 14.8 inches which is already 1.1 inches above the normal amount for a full season according to Capital Weather Gang/Washington Post…15.5 inches for the season so far at IAD).

The next low pressure system in this on-going active pattern will head towards the eastern Great Lakes and given this track to the northwest of the I-95 corridor, warmer air will push northward along the eastern seaboard by later tonight and Thursday. Before the milder air arrives, there can be snow shower activity during the next several hours and then mixed precipitation is likely late today/early tonight. By later tonight, rain is likely in the DC-to-Philly-to-NYC corridor, and it may be just cold enough for freezing on untreated surfaces in some of the normally colder suburbs to the north and west of the big cities. Plain rain is likely to wind down by mid-to-late morning on Thursday and then the winds will pick up noticeably during the afternoon and the intrusion of milder air should lift afternoon temperatures to near the 50-degree mark for highs along the DC-to-Philly-to-NYC corridor.

The weekend will feature a long-lasting storm system that will impact the weather on both Saturday and Sunday. At the onset later Saturday morning or mid-day, it may be cold enough for a burst of snow and/or ice in the Mid-Atlantic region; especially, in those areas to the north of the PA/MD border. Map courtesy NOAA, tropicaltidbits.com

Weekend double-barrel storm...snow/ice possible before a soaking rain

A strong storm system will work its way into the northeastern part of the nation this weekend and can impact the weather in the DC-to-Philly-to-NYC corridor on both Saturday and Sunday. As the initial wave of precipitation arrives on Saturday, it may be cold enough for a burst snow and/or sleet in the Mid-Atlantic region; especially, in areas to the north of the PA/MD border where quick accumulations are even possible. By later Saturday, the colder air will begin to retreat, and any snow or sleet should change over to rain and continue into the day on Sunday. In fact, some of the rain from late Saturday into Sunday can be heavy at times which could raise some flooding concerns given the combination of the soaking rain and the melting of any snow that remains. Low pressure likely cuts up to the northwest of the I-95 corridor by early Sunday and may be positioned over western PA with its trailing cold front making headway towards the Atlantic seaboard. Following the passage of the strong cold front later Sunday, colder air will begin to pour into the Mid-Atlantic region and there is an outside chance that the rain can change to snow in the I-95 corridor for a brief period.

The movement of the MJO into the cold “phases” of 8 and 1 during the next couple of weeks raises the likelihood of colder-than-normal weather across the central and eastern US as these forecast maps imply (week 1 left, week 2 right). Maps courtesy ECMWF, Weather Bell Analytics

Cold outlook for next week...possible east coast storm threat mid-to-late week

The first half of next week looks to be quite cold across much of the central and eastern US with particularly cold air centered over the Great Lakes and Midwest. This idea of colder-than-normal weather next week in the eastern half of the nation is supported by the movement of a tropical disturbance that is tracked 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 the temperature patterns across the nation.

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) and this colder pattern may last all the way into March. Maps courtesy NOAA

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 of February 13-22nd and then into phase 1 around February 23rd or so...both of which suggest colder-than-normal temperatures across much of central and eastern US and this colder-than-normal pattern may last right into the month of March.

There are signs that point to an east coast threat by the middle of next week and any low pressure that does form will have plenty of cold air to work with in the Mid-Atlantic region. Map courtesy ECMWF, Tomer Burg (polarwx.com)

By the middle of the week, strong upper-level low may push from the southwestern states into the south-central US, and this is likely to spawn the formation of low pressure in the Gulf region which will have the ability to tap into plenty of Gulf moisture. This low pressure system is likely to then take a turn up along the eastern seaboard by around the middle of next week and could become a big player; especially, with plenty of cold air around and high-latitude blocking set up over Canada...stay tuned.

Meteorologist Paul Dorian
Arcfield
arcfieldweather.com

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