5:50 PM | ***Wild weather tonight including heavy snow and possible thunder as we enter the final phase of the storm***

Discussion

The final phase of the “Great Storm of 2014” will arrive tonight and it could generate some wild weather conditions. The upper-level low will pass over the Mid-Atlantic region over the next few hours and the result will be “summer-like” snow showers and isolated “thunder snows” are possible as well. The precipitation could start out briefly as rain and/or sleet, but will soon changeover to all-snow as colder air wraps around the storm system into the region. The “cold conveyor belt” region of the storm system located on the northwest side of the surface low pressure center often contains “bands” of precipitation and any of these “bands” can produce significant snow in a short period of time. New accumulations of up to 6 inches are not out of the question in areas that experience “banding snow” and this will result in total accumulations from this storm as high as 20 inches in some of the N and W suburbs of the big cities. All of the activity will wind down by early morning Friday when this storm ends up in the record books for much of the Mid-Atlantic region.

11:20 AM | *****Major nor'easter continues to impact the region through tonight; more accumulating snow on Saturday*****

Discussion

Phase 1 of our major nor’easter is over with its heavy snowfall, phase 2 is now well underway (snow changes to a wintry mix and precipitation slackens off in intensity), phase 3 will take place tonight with more accumulating snow and it actually could be the most interesting with some wild weather possibilities including "banding" of heavy snow and isolated "thunder snows". Snow will mix with or change to sleet, freezing rain and/or rain today and precipitation will lighten up in intensity at times as we enter the “dry slot” section of the storm (see latest radar map). Temperatures will rise to the mid-30's in many locations. Any mixed precipitation will change back to all-snow early tonight and phase 3 will feature snow at varying intensities overnight with more significant accumulations.

By tonight, we will enter the “cold conveyor belt” region of the storm (its northwest flank) and this type of snow is often characterized by “banding” with one location getting pounded while a nearby location is not receiving much at all. Additional snow accumulations overnight of anywhere from a couple to several inches will make total accumulations for this storm end up in the range of 10-14 inches for the big cities of DC, Philly and NYC to 14-20 inches in some of the northern and western suburbs. Winds will be very gusty at times today and tonight - up to 40 mph – so watch out for any loose limbs that are still caught up in the trees since this is really the first strong wind that we’ve had since the massive ice storm (in SE PA). Also, a thunderstorm with snow and/or sleet cannot be ruled out during the storm which winds down early Friday morning. Looking ahead, it looks like another system will bring more significant accumulating snows to the Mid-Atlantic region on Saturday. Today’s storm will turn out to be one of the all-time great storms in one of the all-time great winters in the Mid-Atlantic. As of early this morning, Philly Airport received 8.8 inches of snow from this current storm which makes this officially the 5th snowiest winter of all-time.

7:00 AM | *****Major nor-easter continues to impact the region through tonight*****

6-Day Forecast

Today

Snow mixes with and/or changes to sleet and/or freezing rain from Route I-95 and points east, and possibly in the N and W suburbs, any mixed precipitation is likely to change back to all-snow by the end of the day, a thunderstorm with snow cannot be ruled out as well for today, windy and cold, highs in the low-to-mid 30’s

Tonight

Snow likely, windy and cold, additional accumulations will make total amounts end up in the 10-14 inch range in the District and 14-20 inches in some of the N and W suburbs, lows in the mid 20’s

Friday

Mostly cloudy, brisk, cold, upper 30’s

Friday Night

Mostly cloudy, chance for a few snow showers, cold, low 20’s

Saturday

Becoming cloudy with more accumulating snow possible, quite cold, low 30’s

Sunday

Partly sunny, breezy, cold, near 30

Monday

Partly sunny, cold, mid-to-upper 30’s

Tuesday

Partly sunny, cold, chance for rain or snow showers, low 40’s

Discussion

A powerful nor’easter will continue to impact the DC metro region as it rides up the eastern seaboard. Snow will mix with or change to sleet and/or freezing rain today from Route I-95 and points east, and possibly in some of the northern and western suburbs, but that is no guarantee. The precipitation will come down at varying intensities today and a thunderstorm with snow cannot be ruled out. As the low pressure center pulls by to our east later today, colder air will wrap around it and any mixed precipitation in the area will change back to all-snow as we enter the “cold conveyor belt” phase of the storm on its northwest flank. Snow will continue well into tonight before winding down creating some difficult driving conditions as we approach the Friday morning rush hour. Total snowfall accumulations will be in the 10-14 inch range in the District and 14-20 inches in some of the N and W suburbs by later tonight. More accumulating snow is possible on Saturday.

2:30 PM | ****The Pre-Valentine's Day Massacre****

[Beautiful satellite image of developing storm showing extensive moisture connection to the Gulf of Mexico]

Discussion

A powerful nor’easter will greatly impact the Mid-Atlantic region from DC-to-Philly-to-NYC beginning tonight and lasting right through tomorrow night. This storm has already affected the Deep South with widespread snow and ice and - when all is said and done - it could rival some of the all-time great storms in terms of its extensive impact from the Deep South to northern New England.

It looks like the storm will come in three different phases in the Mid-Atlantic region. The first phase on the front end will feature heavy snow with 1-2 inch per hour rates producing several inches of accumulation. The second phase will see a changeover of the snow to sleet, freezing rain, and/or rain from around Route I-95 to points east, and possibly as far inland as some of the northern and western suburbs of the big cities although that is not a certainty. It is entirely possible that the storm remains as all-snow in some of the northern and western suburbs which, of course, would help out with snow accumulation amounts. The third phase on the back end will see a changeover of any mixed precipitation back to all-snow and this “wrap around” snow in the “cold conveyor belt” region of the storm on its northwest flank will add significantly to the overall accumulations throughout the region.

The snow in the first phase will begin in DC early tonight (by ~7pm), in Philly during the late evening (by ~10pm), and then around midnight in NYC - and the snow will stick in a hurry given the very cold ground conditions. The middle phase featuring the sleet/freezing rain/rain – at least from around Route I-95 and points east - will take place during the day on Thursday and this precipitation will come down at varying rates of intensity. By tomorrow evening, as the storm passes by off the Mid-Atlantic coastline, colder air will return and any mixed precipitation will change back to all-snow and continue until after midnight in an impressive “cold conveyor belt (CCB)”. The CCB region of the storm (northwest flank) is also known as the "deformation zone" and it is often characterized by "bands" of snow which can come down hard at times and even include some possible "thunder snows". Winds will become a factor gusting up to 25-35 mph as we progress through Thursday and Thursday night. The winds at the coastline could gust past 40 mph later tomorrow and tomorrow night.

In terms of snowfall accumulations, there will be a rather sharp gradient from northwest to southeast, but significant accumulations will occur throughout the DC, Philly and NYC metro regions. In general, these metro regions will likely end up in the 8-14 inch range, but even higher amounts are possible in the northern and western suburbs that remain as primarily snow on Thursday during the middle phase of the storm.

7:00 AM | ****Major coastal storm to greatly impact the DC metro region beginning this evening****

6-Day Forecast

Today

Increasing clouds and cold, highs in the upper 20’s

Tonight

Snow developing during the early evening hours and continuing heavy at times through the rest of the night, cold, lows not far from 25 degrees

Thursday

Snow mixing with or changing to sleet and/or freezing rain; especially, from I-95 to points south and east, cannot rule out some “thunder snow”, any mixed precipitation should change back to snow by tomorrow night, highs near freezing

Thursday Night

Snow lingers into the evening; otherwise, mostly cloudy, windy, total accumulations of 8-14 inches, cold, low-to-mid 20’s

Friday

Becoming partly sunny, cold, near 40

Saturday

Partly sunny, breezy, cold, maybe a few snow showers, mid 30’s

Sunday

Partly sunny, cold, more snow showers possible, upper 30’s

Monday

Partly sunny, cold, near 40

Discussion

A major east coast storm will greatly impact the DC metro region from this evening into tomorrow night with the biggest snow accumulations of the year in many areas. This storm has already caused major problems in the Deep South in terms of ice and snow and a widespread swath of heavy snow is likely over the next 48 hours from the higher elevation mountains of the Carolinas to northern New England and significant icing is possible just to the south and east of this heavy snow accumulation band.

Strong low pressure will move to around Norfolk, VA by later tonight on its way to just off the New Jersey coastline by tomorrow evening and then to near Cape Cod, MA by early Friday. Snow should begin later this evening around here and continue into Thursday and then mixing with or changing to sleet and/or freezing rain for awhile; especially, from I-95 to points south and east. If a changeover to mixed precipitation does indeed occur, then it’ll likely change back to “wrap-around” snow later tomorrow as we enter the “cold conveyor belt” region of the storm on its northwest flank. There is also the possibility for some “thunder snow” to occur during this upcoming event and expect varying precipitation intensities on Thursday. The snow will linger into tomorrow night potentially forcing driving problems to continue into early Friday. Current snowfall estimates are in the 8-14 inch range with the higher amounts in that range occurring in the northern and western suburbs and the lesser amounts to the south and east.

Video

httpv://youtu.be/vz19gIrmf6U

2:00 PM | ****Powerful coastal storm to have a big impact on a large part of the country****

[00Z Euro model surface forecast map for early Thursday evening; map courtesy of College of DuPage Meteorology]

Discussion

A major east coast storm will not only greatly impact the Mid-Atlantic region from Wednesday night through Thursday night, but it will be a major news making event from the Deep South to New England during the next 72 hours or so with massive icing in some areas and 1-2 feet of snow in others. While there are still some disagreements amongst the many computer forecast models and some important details that still need to be ironed out regarding the unfolding event, it is increasingly clear that a powerful storm will track from near Norfolk, VA late Wednesday to just off the New Jersey coastline by late Thursday and then to near Cape Cod, MA by early Friday. There is likely to be a widespread path of heavy snow of a foot or more extending from the western Carolina mountains to northern New England by the time all is said and done and a major ice storm will occur in many locations just to the south and east of the heavy snow band from the Deep South to the Northeast US.

Snow is likely to begin in the DC metro region during the early evening hours on Wednesday and then near or after midnight across Philly and NYC. The Wednesday evening rush hour appears to be safe from the upcoming storm, but all bets are off for Thursday and even early Friday. The storm will be in full throttle for both rush hours on Thursday in the Mid-Atlantic region and Friday morning may still be quite problematic given the fact that the “wrap-around” snow in the “cold conveyor belt” region of the storm (northwest flank) can last right into Thursday night. In fact, the “wrap-around” snow looks quite impressive on the back side of the storm late Thursday. There still is the question as to how much mixing of sleet and/or freezing rain will occur during this storm with the greatest chances of mixing from I-95 to points south and east. The northern and western suburbs of the big cities may stay as primarily snow, but even in those areas a changeover to sleet and/or freezing rain can occur on Thursday. It is possible that the storm results in the scenario of “snow changes to a mixture and then changes back to snow” and, by the way, "thundersnow" is also in the pciture for this storm. Preliminary snowfall estimates are 8-14 inches in and around the DC, Philly and NYC metro regions with the higher amounts in that range occurring in the northern and western suburbs and the lower amounts to the south and east.

As far as the computer forecast models are concerned, the GFS (NOAA) model has indeed come farther to the north and west with the pending coastal storm and it has strengthened it as well compared to its earlier runs, but the European computer forecast model is still the most impressive in terms of storm strength and precipitation amounts. Last night’s 00Z Euro model run depicted a powerful storm just off the Mid-Atlantic coastline as of early Thursday evening. The Euro model has been quite consistent and experience says that when the Euro is locked into one solution - as it has been in recent days - then it is best to go with it. [Surface map from 00Z Euro model run showing powerful storm off the Mid-Atlantic coastline as of early Thursday evening; map courtesy College of DuPage Meteorology].

Finally, let me point out that there will be a couple of smaller events this weekend that could bring a little more snow to the Mid-Atlantic region.

7:00 AM | ***A major east coast storm will impact the region tomorrow night and Thursday with significant snow and some icing as well***

6-Day Forecast

Today

Mostly sunny skies, very cold, highs in the upper 20’s

Tonight

Mostly clear, bitter cold, lows in the low teens

Wednesday

Increasing clouds, very cold, upper 20’s

Wednesday Night

Snow developing in the early evening hours, cold, mid 20’s

Thursday

Snow likely, possibly mixing with sleet and/or freezing rain at times, cold, mid 30’s

Friday

Mostly sunny, breezy, cold, near 40

Saturday

Partly sunny, cold, mid-to-upper 30’s

Sunday

Mostly cloudy, cold, snow showers possible, mid 30’s

Discussion

First the good news...pitchers and catchers report in Florida this week and there are signs for warmer weather during the next couple of weeks. Now the bad news...in the winter that seemingly never ends, there is a major east coast storm headed our way for tomorrow night and Thursday and it should bring substantial snow to the region with some icing possible as well; especially, from Route I-95 to points south and east.

Today will feature very cold conditions for this time of year and bitter cold tonight will drop temperatures to the teens throughout the region. Clouds increase on Wednesday and snow is likely to develop in the early evening and continue through the day on Thursday with the chance for some mixing of sleet and/or freezing rain; especially, from Route I-95 to points south and east. Preliminary snowfall estimates for the DC metro region are 8-14 inches with the higher amounts in that range in the northern and western suburbs where primarily snow can fall and the lesser amounts to the south and east where more of a mixing will likely occur. It looks like there will be numerous school closings on Thursday and that could be the case on Friday as well as the dig out begins.

Video

httpv://youtu.be/iV1M3vp9byw

3:00 PM | ***The threat continues for a major east coast storm on Wednesday night and Thursday with substantial snow and ice accumulations possible; especially, in the northern and western suburbs***

[European model forecast map for early Thursday; courtesy College of DuPage Meteorology]

Discussion

The threat for a major east coast storm continues for the Wednesday night/Thursday time frame and significant snow and ice accumulations are possible in the Mid-Atlantic region. There is likely to be a battle zone pretty close to the I-95 corridor between colder air and primarily snow to the west and slightly warmer air with snow changing to mixed precipitation to the east. The greatest chance for substantial snow and ice in the Mid-Atlantic region is from the northern and western suburbs of the big cities (DC-to-Boston) inland to the Appalachian Mountains.

Strong surface low pressure will track along the Gulf coast on Wednesday and then up the eastern seaboard on Thursday likely taking a track from around Norfolk, Virginia to near Atlantic City, New Jersey. The Southeast US will likely experience a major ice storm on Tuesday night and Wednesday in, for example, cities like Atlanta, Georgia and Charlotte, North Carolina. Interior sections of Virginia will likely get pounded with heavy snowfall from Wednesday night into Thursday. The computer models have come into somewhat better agreement on the idea of a strong coastal storm, but, once again, the GFS (NOAA) model is weaker and slightly farther to the southeast compared to some of the other models.

The Canadian model forecast map shows heavy snow in the region between DC, Philly and New York City as of Thursday morning (below). The European model has a powerful storm in eastern North Carolina as of Thursday morning (forecast map above). Stay tuned.

[Canadian model forecast map for early Thursday]

7:00 AM | ***A major east coast storm threat on Wednesday night and Thursday with the potential for significant snow***

6-Day Forecast

Today

Partly sunny skies, cold, highs in the low 30’s

Tonight

Partly cloudy, very cold, lows in the mid-to-upper teens

Tuesday

Mostly sunny, very cold, upper 20’s

Tuesday Night

Partly cloudy, very cold, mid-teens

Wednesday

Increasing clouds, cold, snow likely at night, low 30’s

Thursday

Cloudy, cold, snow likely, possibly mixed with ice or rain at times, mid-to-upper 30's

Friday

Partly sunny, cold, near 40

Saturday

Mostly cloudy, cold, upper 30's

Discussion

Our active weather pattern continues this week with the threat for a major east coast storm on Wednesday night and Thursday that could generate significant snow from DC-to-Boston. One of the indications that suggests there will be a major storm along the east coast later this week has to do with what occurred this weekend in the Far East. Some may have heard that Tokyo, Japan had 20 inches of snow - one of their biggest storms in years - and a deep trough of low pressure in the Far East often translates to a deep trough in the eastern US several days later. While a strong storm is likely, some details still have to be ironed out with respect to precipitation-type. The rain/snow line during this storm is likely to start off between the big cities along the I-95 corridor and the coastline and it could back westward into the big cities allowing for snow to mix with sleet and/or rain at times on Thursday which would have an important impact on ultimate snow accumulation amounts. In fact, one factor going against an all-snow event in the big cities is the positioning of the high pressure to the north during this storm time period as it looks like it will move off the Northeast US coastline which will make it more difficult - though not impossible - to stay as all snow in the I-95 corridor. Another still-to-be-resolved detail is the fact that the main US computer forecast model, Global Forecast System (GFS), currently has a storm track quite far off the east coast with minimal impact around here whereas other models have the storm riding right up the east coast with a significant impact on the region. The GFS model is probably exhibiting its usual "southeast" bias in east coast storm tracks and will likely pull the storm closer to the east coast as the event time nears. Stay tuned, today's video has a detailed breakdown of several different model runs from last night including the GFS, NAM, European and Canadian.

Video

httpv://youtu.be/EYulJLA4aJ8

12:30 PM | Accumulating snow Sunday PM on the order of 2-4 inches in the Philly metro region

Discussion

Accumulating snow Sunday PM Our active weather pattern continues from this weekend right into the second half of the upcoming week. Today features a relatively weak upper-level disturbance in the southern branch of the jet stream that is generating low pressure off of the Mid-Atlantic coastline. This system will only brush the I-95 corridor with snow this afternoon and little in the way of accumulations. The heaviest precipitation today associated with this southern system will stay well to the southeast of the I-95 corridor. Another upper-level disturbance will ride this way on Sunday from our west in the northern branch of the jet stream. This system has more punch than today’s southern system and the result will likely be accumulating snow for much of the Mid-Atlantic region. As this northern system approaches the Mid-Atlantic coast on Sunday it will intensify somewhat and snow should break out during the afternoon hours. Snow should then continue well into the evening in many I-95 corridor locations and it could actually come down hard at times causing some slick road conditions. In the I-95 corridor from DC-to-Philly-to-NYC, the timing for the snow on Sunday is roughly between 2 and 9PM with 2-4 inches of accumulation by late evening in the Philly metro region and 1-3" in and around the NYC metro region. In the DC metro region, there will be slightly less in the way of total precipitation amounts and also some "precipitation-type mixing" issues; consequently, snow accumulations will be on the lighter side with perhaps little or nothing in the District and an inch or two across the northern suburbs.

Looking ahead to the next threat and it's a big one Dry and very cold weather will dominate the scene in the Mid-Atlantic from Monday into Wednesday with single digit low temperatures possible once again in much of the region. There continue to be signs that a strong wave of low pressure will pull out of the Deep South by Wednesday night or Thursday of next week and head towards the east coast with lots of available moisture. As a result, the threat for significant snow, ice or rain will likely return to the region during the second half of next week, but it is too early for details on this one so stay tuned.

An update on the western US From very dry-to-very wet across northern California…there can be between 6 and 10 inches of rain in the northern half of California over the next 5 days or so. In addition, higher elevation locations out west from California to Colorado can receive several feet of snow in the next several days - particularly hard hit will be the Wasatch Mountains of Utah.

Saturday solar update on the "Climate Info" page.