Coldest Air of the Season Arriving
The coldest air of the season is now plunging into the Midwest and will spread to the Northeast early in the new week ahead.
RyanMaueRyan Maue 19 jan
Heart of coldest-air in a while for Great Lakes, actual 850 mb temps of -37°C — worse of it 23°C below normal
A 2nd, more potent snowstorm for Thursday night and Friday. #Boston #NYC
In the wake of this snow event, bitterly cold air will take hold of the entire Northeast for Tuesday and Wednesday. No community–even those down to northern Virginia and most of the Delmarva–will record a high above freezing either of these days.
Highs in the single digits, on either side of zero, will be common throughout far northern New England.
The brutal cold at midweek will set the stage for the workweek to end with a snowstorm, one that could bring substantial snow to a larger corridor of the Northeast than the late Monday-Tuesday event.
January 24-27 Potential Significant Winter Storm (Updated 1/20)
By Andrew at 10:18 AM
There is potential for a winter storm from January 24th to January 27th across much of the nation east of the Rockies. Let’s do a model analysis and see what the latest forecasts hold.
Shown above is the GFS forecast, valid for the morning of January 25th. We can see the storm system is centered in eastern Tennessee, with precipitation also shown. Snow is shown in blue, and rain is forecasted in the traditional green colors. We see the system is moving relatively eastward towards the Mid-Atlantic, dropping some accumulating snow as it goes. This snow would most likely accumulate in the northern Mid-Atlantic, with cold air still in place following this weekend’s cold outbreak and additional cold air following in the wake of this system.
It should be noted that the GFS model has been swaying from a north track (snow hits the Midwest and northern Ohio Valley) to a south track (snow impacts the areas shown above), reducing my trust in its credibility. Now that we have seen the southern track, let’s take a glance at the north track.
The highly-respected ECMWF model and its ensemble system (commonly called the EPS) are supporters of the northern track at this time. The ECMWF takes the system a bit north of its ensembles, putting the storm system in south central Indiana. Enough cold air would be in place to theoretically give snow to many of the areas described in the small paragraph above these images, like the Midwest, Ohio Valley and into the Lower Great Lakes. The EPS takes the storm system just a few hairs south of the operational ECMWF model, but nonetheless would keep accumulating snow within the same relative realm of the ECMWF model itself. A quick glance at ECMWF snow accumulations on a pay-to-view site agrees with my above thoughts in a swath of accumulating snow in Illinois, Indiana, Michigan and Ohio, to name a few states.
The Canadian GGEM model, usually not one to be in sync with other models, appears to be lining up relatively well with the ECMWF model, The low pressure system is a bit further north on the GGEM model, and temperatures are warmer than the ECMWF model, but the Canadian model can still theoretically be defined as in the north track. Although I don’t really care for the GGEM on account of its messy track record, it’s in one of the tracks at this time, and thus deserves to be noticed.
At the moment, looking at various teleconnections, I am seeing the Pacific-North American index go negative during this timeframe. This means negative pressure anomalies (low pressure) on the West Coast (hence negative PNA), which causes high pressure to build in the East. This would most likely prevent suppression of this storm, giving some strength to the North Camp. The Madden-Julian Oscillation (MJO) will be in a phase favorable for making storms stay away from the Deep South and instead taking a more northern route like the ECMWF/EPS are suggesting. The North Atlantic Oscillation (NAO), which, in its negative phase can cause Nor’easters, will be too weak to help this situation out.
My preferred forecast: ECMWF/EPS solution. Snow accumulates in Midwest, Ohio Valley and Great Lakes. Heaviest totals hit Illinois, Indiana, Ohio and Michigan, among others. Accumulations range from 2 inches to 6 inches. Confidence: 60%
January 24-27 Potential Significant Winter Storm – 1/20 Evening Update
By Andrew at 4:58 PM
This is the current situation unfolding with the potential winter storm that would fall within the timeframe of January 24-27. I have displayed the two most reliable weather models’ ESTIMATED tracks (I say estimated because I believe the ECMWF is actually a bit further south) for this storm system. There is a very messy agreement that the storm will happen, but that’s where the line is drawn. While the ECMWF projects widespread accumulations, much of which falls within the blue ‘Potential Accumulating Snow’ area, the GFS is much more restricted on snow, with only parts of the Ohio Valley and Northeast benefitting.
At the moment, out of consistency, lower cyclone track error and overall better verification in recent runs than the GFS, I’m feeling much better siding with the ECMWF than the GFS. I feel that the GFS is just too wobbly for my liking, while the ECMWF has a swath of accumulating snow down pat in a situation much more fit to happen with frigid Arctic air to the immediate north. Additionally, the ECMWF’s ensemble system is in good agreement with the blue ECMWF track, greatly enhancing the credibility of such a track. On the contrary, the GFS’ ensemble system is disorganized with this system and should not be taken at face value- it faces some of the same issues as the GFS model itself.
At the moment, I will side with the blue track, but I will not map out accumulations due to model disagreement that I am not comfortable deciphering for the time being.
Exciting times ahead for many in this nation!
WWUS41 KBOX 210911
URGENT – WINTER WEATHER MESSAGE
NATIONAL WEATHER SERVICE TAUNTON MA
411 AM EST MON JAN 21 2013
…ACCUMULATING SNOW DEVELOPS BY THIS EVENING AND CONTINUES AT
TIMES TONIGHT BEFORE TAPERING OFF TUESDAY MORNING…
SOUTHEAST MIDDLESEX MA-SUFFOLK MA-EASTERN NORFOLK MA-
INCLUDING THE CITIES OF…CAMBRIDGE…BOSTON…QUINCY
411 AM EST MON JAN 21 2013
…WINTER WEATHER ADVISORY IN EFFECT FROM 4 PM THIS AFTERNOON TO
10 AM EST TUESDAY…
THE NATIONAL WEATHER SERVICE IN TAUNTON HAS ISSUED A WINTER
WEATHER ADVISORY FOR SNOW…WHICH IS IN EFFECT FROM 4 PM THIS
AFTERNOON TO 10 AM EST TUESDAY. THE WINTER STORM WATCH IS NO
LONGER IN EFFECT.
* LOCATIONS…PORTIONS OF EASTERN MASSACHUSETTS.
* HAZARD TYPES…SNOW.
* ACCUMULATIONS…SNOW ACCUMULATION OF 2 TO 4 INCHES.
Snow (and rain) showers Monday night can make for dangerous travel for Midwest, mid-Atlantic & New England