7:00 AM | Mild to start off the new work week...rain pushes in for later Tuesday...spring fever alert for Wednesday...rain or snow at the end of the week

6-Day DC Forecast

Today

Becoming partly sunny, milder, highs in the mid-to-upper 50’s

Tonight

Mostly cloudy, chilly, lows in the upper 30’s

Tuesday

Cloudy, cool, rain likely later in the afternoon, low-to-mid 50’s

Tuesday Night

Cloudy, cool, rain likely, low 40's

Wednesday

Mostly cloudy, milder, upper 50’s

Thursday

Partly sunny, mild, low 50's

Friday

Mostly cloudy, colder, chance for rain or snow, mid--to-upper 40’s

Saturday

Mostly cloudy, chilly, chance for rain, upper 40’s

Discussion

Temperatures today should reach well into the 50's with partial clearing skies and it could climb to near 60 degrees on Wednesday. Clouds will dominate on Tuesday keeping us slightly cooler than today and rain is likely later in the day and tomorrow night. Late in the week, colder air will be pushing in from the north and a large area of moisture will advance northward into the Mid-Atlantic region from the southern states. As a result, rain or even snow could break out at the end of the work week.

Video

httpv://youtu.be/L9F0rQlpcb4

7:00 AM | Big break coming in the overall pattern, but winter is not over yet

[Pretty amazing to see 54% of the US with snow cover in early March (through mid-day Thursday); map courtesy Weather Bell Analytics]

6-Day DC Forecast

Today

Brilliant sunshine today, but very cold, highs only reaching the mid-to-upper 20’s

Tonight

Partly cloudy, brutally cold, lows in the single digits

Saturday

Partly sunny, still quite cold, but not as harsh, near 40 degrees

Saturday Night

Mostly cloudy, cold, mid-to-upper 20’s

Sunday

Partly sunny, moderate cold, upper 40’s

Monday

Partly sunny, a bit milder, low 50’s

Tuesday

Partly sunny, chilly, chance for showers, low 50’s

Wednesday

Partly sunny, mild, mid 50’s

Discussion

Very cold conditions will ease up this weekend and it’ll get noticeably milder as we progress through next week. However, despite this upcoming significant break in the overall weather pattern, winter is likely not through with us yet. Colder-than-normal weather is quite likely to return to the Northeast US later this month and last into April and there can even be more threats of snow.

A quick recap of this morning’s amazing cold and yesterday’s biggest snowfall of the year: 1) Record cold this morning for the date at Reading, PA, Allentown, PA, Wilmington, DE, Atlantic City, NJ, Dulles Airport, VA, Baltimore, MD 2) All-time record cold this morning for the month of March at Pittsburgh, PA, Harrisburg, PA 3) Snow totals yesterday at the 3 DC Airports (all daily snow records): DCA 4.8”, BWI 6.2”, IAD 9.4” 4) Philly region: 7.5” at PHL, 10.4” in King of Prussia 5) NYC region: Bronx 6.6”, Central Park 7.0”, JFK 5.8”

7:00 AM | *****Snowstorm today after transition to snow completes in the region from north-to-south...heavy snow from mid-morning through the afternoon...brutally cold overnight*****

6-Day DC Forecast

Today

Precipitation transitions to all snow from north-to-south by mid-morning and continues heavy at times right through the afternoon with significant accumulations, breezy and cold with temperatures dropping throughout the day

Tonight

Still the chance for snow early then becoming partly cloudy and brutally cold, lows by tomorrow morning in the single digits

Friday

Mostly sunny, very cold, mid 20’s

Friday Night

Partly cloudy, brutally cold, single digits possible for lows

Saturday

Mostly sunny, cold, upper 30’s

Sunday

Mostly sunny, still cold, but not as harsh, near 45 degrees

Monday

Mostly sunny, milder, near 50 degrees

Tuesday

Mostly sunny, mild, mid 50’s

Discussion

An influx of colder air is transitioning all precipitation to snow from north-to-south and the snow will continue, heavy at times, from mid-morning right through the afternoon throughout the DC metro region. Temperatures will actually drop as the day progresses and then bottom out late tonight in the single digits following today’s snowfall - perhaps in record-breaking territory. Accumulations should average 6-10 inches in the DC metro region, and even higher amounts are possible in isolated spots. The higher amounts in that range will tend to occur to the north and west of DC and the lower amounts inside the District and points south and east. It’ll stay very cold on Friday to close out the work week despite brilliant sunshine, but then temperatures will modify slowly over the weekend along with dry weather conditions. Despite a substantial break in the overall pattern, this is likely not winter's last blast. The snow will begin the day on the "heavy, wet" side clinging to the previously wet branches and other surfaces, but may end up "drier and fluffier" later in the day as temperatures continue to drop.

1:15 PM | ****Significant snow late tonight and Thursday****

[12Z GEM model forecast map of total snowfall accumulations during this upcoming event; courtesy tropicaltidbits.com]

Discussion

Overview We are now in phase 2 of this 3-day weather event. Phase 1 featured lots of freezing rain and sleet late yesterday with numerous slippery spots during the evening commute in the Philly metro region. Today’s phase 2 brings us noticeably milder conditions with occasional rain and the touch of fog in some areas. Phase 3 will feature colder air moving in from the northwest and moisture moving in from the southwest. The cold and moisture will meet to bring the I-95 corridor significant snow from late tonight through much of the day on Thursday. Six inches of snow is a pretty safe bet as a minimum in most areas along the I-95 corridor with the chance for considerably more than that and all of this follows rain this evening and then a period of sleet later tonight.

Timetable, snowfall estimates Occasional rain will fall right into the evening hours in DC, Philly and NYC at the same time colder air is filtering in from the northwest to the southeast. The rain will change to a period of sleet during the middle of the night and this should then transition to snow late tonight from the northwest to the southeast. Specifically, the transition to snow should take place between 1 and 4 am in the NYC and Philly metro regions and 5-8am in the DC metro region. The snow should continue well into the afternoon in all areas and then taper off during the late afternoon or early evening hours. DC’s best snows will likely take place between mid-morning and mid-afternoon whereas Philly and NYC will likely see their best snows from the pre-dawn hours to mid-day. Temperatures will drop through the day on Thursday and bottom out in the single digits in some areas by early Friday morning.

Accumulation estimates are as follows:

6-10 in the DC metro region with the higher amounts in that range likely to the north and west of the District and the lower amounts in the District and nearby points to the south and east

6-10 in the Philly metro region with the higher amounts in that range likely in Philadelphia and nearby areas and the lower amounts well to the north and west of the city; central and south New Jersey also fall into the 6-10 inch range

4-8 inches in the NYC metro region with the higher amounts in that range from the metro region and points south and east and the lesser amounts to the north and west

Stay tuned...small shifts can have a big impact.

Morning Video Discussion

httpv://youtu.be/_Jx_2Rjhk24

6:00 AM | *****Threat continues for the biggest snowfall of the year between late tonight and late tomorrow*****

6-Day DC Forecast

Today

Becoming milder with occasional rain, some patchy fog possible, highs reaching the low-to-mid 40’s

Tonight

Rain early changes to sleet and then to accumulating snow after midnight, turning colder with lows by morning in the upper 20’s

Thursday

Periods of snow with significant accumulations on the order of 6-12 inches before it winds down, quite cold, highs in the upper 20’s early in the day

Thursday Night

Chance for snow early then becoming partly cloudy, brutally cold, upper single digits for lows

Friday

Mostly sunny, very cold, mid 20’s

Saturday

Mostly sunny, still cold, but not as harsh, low 40’s

Sunday

Mostly sunny, cold, mid 40’s

Monday

Mostly sunny, milder, low 50's

Discussion

Today promises to be a milder day with periods of rain and some patchy fog possible; however, the more important story will be the arrival of another Arctic cold frontal system. This front will pass through the region late in the day and this will begin a downward trend in temperatures that could set the stage for a snowstorm in the I-95 corridor later tonight and Thursday. Once the Arctic front reaches the east coast, it will stall out due to the alignment of the upper-level winds which will prevent any significant movement to the southeast. At the same time, copious amounts of moisture will begin heading northeast along the stalled out frontal boundary zone as colder air pushes in from the northwest. The result could very well be the biggest snowfall of the year for the DC metro region with 6-12 inches on the table between late tonight and late Thursday.

Video

httpv://youtu.be/_Jx_2Rjhk24

12:45 PM | ****Spotty snow, sleet next couple hours, but then more widespread mixed precipitation for the mid and late afternoon hours...Snowstorm threat late Wednesday night/Thursday****

[Tuesday 12Z Canadian forecast map for Thursday mid-day (blue=snow)]

Discussion

Overview The next 48 hours will be quite wild in the I-95 corridor region from DC-to-Philly-to-NYC. First, more snow and ice will develop later this afternoon and continue into the evening. This will very likely create numerous slippery spots for the evening commute with a fresh coating to an inch or two of snow/ice accumulations. Then, milder air will push in overnight, and any wintry mix that falls this evening should change to plain rain by late tonight and Wednesday promises to be a milder day with occasional rain and patchy fog possible. After that, the potential exists for the biggest snowfall of the year from late Wednesday night into Thursday which could very well shut things down in the I-95 corridor on Thursday.

Snow, ice threat for this afternoon and evening Current radar shows spotty snow and sleet developing just to the west of DC and Philly. The entire region from DC-to-Philly-to-NYC should see spotty snow and/or sleet during the early afternoon hours, but then the mixed precipitation becomes more widespread during the mid-to-late afternoon hours. There will likely be numerous slick spots for the evening commute and a coating to an inch or two of snow/ice is quite likely by later this evening. Milder air will cause the wintry mix to transition to plain rain in most locations by late tonight as temperatures slowly rise.

Wednesday – milder with plain rain Wednesday promises to be a milder day with periods of rain. Temperatures could even flirt with the 50 degree mark on Wednesday in southern portions of the I-95 corridor. The more important story; however, will be the approach of another Arctic cold frontal system. This front will pass through the region late Wednesday and this will begin a downward trend in temperatures that could set the stage for a snowstorm in the I-95 corridor from late Wednesday night into Thursday.

Late Wednesday night/Thursday – Snowstorm threat Once the Arctic front reaches the east coast, it will stall out due to the alignment of the upper-level winds which will prevent any significant movement to the southeast. At the same time, copious amounts of moisture will begin heading northeast along the stalled out frontal boundary zone and colder air will be pushing in from the northwest. The result could very well be the biggest snowfall of the year in DC, Philly and NYC with 6-12 inches of accumulation on the table. Very cold weather closes out the work week.

[Tuesday 12Z GFS snowfall forecast map for the late Wednesday night/Thursday storm]

7:00 AM | **Another round of snow and/or ice later today...milder tomorrow with plain rain...significant snow possible on Thursday**

6-Day DC Forecast

Today

Cloudy, cold, snow or a wintry mix breaks out during the early-to-mid afternoon hours, slick travel conditions possible for the evening commute with a coating to an inch of snow and ice accumulations, highs in the low-to-mid 30’s

Tonight

Wintry mix changes to plain rain as temperatures slowly rise, some fog possible late

Wednesday

Becoming noticeably milder with rain likely at times, some fog possible, quite breezy, near 50 degrees

Wednesday Night

Rain likely early, but it should change to snow by morning, turning colder, mid-to-upper 20’s by morning

Thursday

Snow likely with significant accumulations, much colder than Wednesday, upper 20's for highs

Friday

Mostly sunny, breezy, very cold, upper 20's

Saturday

Mostly sunny, still cold, but not as harsh, low 40's

Sunday

Mostly sunny, chilly, near 45 degrees

Discussion

Clouds will thicken up this morning and another round of snow and/or ice is headed our way. Precipitation should break out by early afternoon - probably as a mix of snow and sleet - and then freezing rain will likely mix in by the end of the day. There can be some slick travel conditions for the evening commute with a coating to an inch of snow/ice accumulations possible. The wintry mix should change to plain rain during the evening hours as temperatures rise slowly and some fog is possible late. Wednesday promises to be a milder day with occasional rain and some fog; however, the more important story will be the approach of yet another Arctic cold frontal system. That front will pass through the region late Wednesday and this will begin a downward trend in temperatures that could set the stage for significant snow on Thursday.

Once the Arctic front reaches the east coast, it will stall out due to the alignment of the upper-level winds which will prevent any significant movement to the southeast. At the same time, copious amounts of moisture will begin heading northeast along the stalled out frontal boundary zone and colder air will be pushing in from the northwest. The result could very well be a significant snow event on Thursday with preliminary estimates in the 4-8 inch range for the I-95 corridor. Very cold weather closes out the work week.

Video

httpv://youtu.be/EF53UXta-Io

1:30 PM | ****Wow, talk about "coming in like a lion"!!****

[12Z Canadian model forecast map for mid-day Thursday (blue=snow].

Discussion

Overview March began with snow and ice on Sunday, more snow and/or ice is coming for tomorrow afternoon and evening and then, after a temporary warmup on Wednesday, a significant snow event is possible from late Wednesday night into Thursday. Before we get into the details on the very active next few days, let us first throw out some new numbers regarding the amazingly cold February which just ended.

February recap for DC, Philly, NYC At Reagan National Airport in Washington, DC (DCA), February 2015 was the coldest month at any time of the year since January 1994. DCA saw seven days completely below freezing which is the most in any month since 1979. Dulles Airport in Virginia (IAD) recorded its 2nd coldest February ever and BWI Airport in Maryland saw its coldest February since 1934 (source Washington Post/Capital Weather Gang).

In Pennsylvania, February 2015 was the coldest February ever in State College, Erie, Williamsport and Harrisburg. At Philly International Airport (PHL), this was the 7th coldest February ever recorded going back to 1874 and the coldest month at any time of the year since December 1989 (source phillywx.com).

In New York City, February 2015 turned out to be the third coldest February ever and the coldest since 1934. It was the 2nd coldest February ever recorded in Newark, NJ.

Finally, here is just a sampling of places which set their all-time monthly (cold) temperature records: Buffalo (NY), Islip (NY), Hartford (CT), Bridgeport (CT), Syracuse (NY) and Bangor (ME).

Tuesday afternoon and evening - snow, ice threat After a very cold night in which temperatures drop into the teens, clouds will thicken up early Tuesday ahead of the next precipitation event. Precipitation is likely to break out during the mid-day or early afternoon hours in DC, mid-to-late afternoon hours in Philly and New York City, and it should be cold enough for that initial precipitation to be of the frozen variety. In DC, the precipitation could start as all snow, but a wintry mix is more likely whereas in Philly and NYC the precipitation is liable to begin as all snow. In all areas, any initial snow will change over to a wintry mix fairly quickly later tomorrow or early tomorrow night and, yes, there can be some snow and ice accumulations by midnight. Temperatures tomorrow night should slowly rise and any mixed precipitation is likely to change to plain rain by early Wednesday.

Wednesday – milder with plain rain Wednesday promises to be a milder day with periods of rain. Temperatures could even flirt with the 50 degree mark on Wednesday in portions of the I-95 corridor. The more important story; however, will be the approach of another Arctic cold frontal system. This front will pass through the region late Wednesday and this will begin a downward trend in temperatures that could set the stage for significant snow on Thursday.

Late Wednesday night/Thursday – potential significant snowfall Once the Arctic front reaches the east coast, it will stall out due to the alignment of the upper-level winds which will prevent any significant movement to the southeast. At the same time, copious amounts of moisture will begin heading northeast along the stalled out frontal boundary zone and into the I-95 corridor. At the same time, colder air will be pushing in from the northwest and the result could very well be a changeover rain early in the day to an accumulating snow and significant accumulations are possible up and down the I-95 corridor.

7:00 AM | ***Week starts off on the cold side...much milder by mid-week, but the warm up will be short-lived and preceded by a wintry mix and then plain rain...cold air returns later this week possibly with significant accumulating snow on Thursday***

6-Day DC Forecast

Today

Becoming partly sunny after early clouds, winds will intensify at mid-day and for the afternoon, cold, highs in the low 40’s

Tonight

Partly cloudy, quite cold, lows in the lower 20’s

Tuesday

Becoming cloudy, cold, snow or a wintry mix arrives during the afternoon, mid-to-upper 30’s

Tuesday Night

A wintry mix becomes plain rain, cold, but temperatures should slowly rise through the 30's

Wednesday

Becoming noticeably milder with showers likely early, breezy, low 50’s

Thursday

Cloudy, breezy, much colder, rain changes to snow early with significant accumulations possible, low-to-mid 30’s

Friday

Mostly sunny, cold, mid 30’s

Saturday

Mostly sunny, milder, mid 40’s

Discussion

Our active weather pattern will continue for the next several days with a potpourri of weather conditions including snow, sleet, freezing rain, plain rain, and the chance for a substantial snow accumulation. The new work week start off on the cold side and the winds will intensify during the mid-day and afternoon hours. After a very cold overnight, clouds will thicken up early Tuesday and snow or a wintry mix is likely to arrive during the afternoon hours. Incoming milder air will gradually change the precipitation to plain rain tomorrow night as temperatures slowly rise through the 30's. Wednesday promises to be quite mild ahead of the next Arctic frontal system with periods of rain and temperatures reaching the 50 degree mark.

That Arctic frontal system will slow down as it reaches the east coast and will set off a chain of events that could bring a significant snowfall to the I-95 corridor. Copious amounts of moisture will ride along the frontal boundary zone Wednesday night and Thursday as colder air pushes into the Mid-Atlantic region. This type of setup could feature a cold rain that changes to snow by early Thursday with significant accumulations possible. Very cold conditions will follow for the end of the work week.

Looking ahead, next weekend looks to be moderately cold and then another shot of Arctic air is possible early next week. Beyond that, there are signs for an important break in the pattern centered around the middle of the month with several days of milder weather conditions. However, it is quite likely that we'll return to a colder-than-normal pattern - perhaps stormy as well - during the latter part of the month and going into April.

Video

httpv://youtu.be/A7UqcJjbJPQ

8:45 AM | ***Accumulating snow and the threat for a significant buildup of ice***

[US radar image with plenty of moisture headed to the Mid-Atlantic region; NEXRAD image courtesy University of Wisconsin]

Discussion

Overview Dense, cold Arctic air sits on top of the Mid-Atlantic region this morning and copious amounts of moisture (radar map) is streaming in from the west – a bad combination that spells big trouble for the I-95 corridor region from DC-to-Philly-to-NYC. Accumulating snow is likely in all areas along I-95 at the onset of today's precipitation event, but that ultimately will not be the biggest problem. Milder air moving northward in the upper part of the atmosphere will generate a changeover from the snow to sleet and then to freezing rain in most areas and there can be a significant buildup of ice on untreated surfaces (e.g., trees, grass, untreated roadways) with slick travel conditions. While the upper atmosphere turns milder, the dense, cold and below-freezing Arctic air at ground level will be reluctant to retreat; thereby, setting the stage for some serious ice buildup later today and early tonight in portions of the area.

Details Snow is likely to break out by mid-morning in the DC metro region perhaps even mixed with some sleet in southern sections, in the late morning to mid-day hours across Philly, and then during the early afternoon in the NYC metro region. Then, after a period of accumulating snow, there will then be a transition later today from south-to-north of the snow to sleet and then to freezing rain although snow will hang on for much of this event in higher elevation locations north of I-80 (e.g., NE PA). Before the changeover to ice, snow should accumulate from a coating to an inch or two in and around the DC metro region, 1-3 inches in the Philly metro region, and 2-4 inches in the NYC metro region. The higher amounts in those snowfall accumulation estimates will occur to the north in a given metro region and the lesser amounts to the south. A significant ice-buildup (quarter to half an inch) is possible later today into early tonight in the entire I-95 region from DC-to-Philly-to-NYC. Precipitation winds down by or shortly after midnight in most of the I-95 corridor.

“Banding” could enhance snow (or ice) totals in parts of the area One final word of caution on today’s event…there will be an impressive thermal gradient in the Mid-Atlantic region and strong upward motion in the atmosphere as a powerful upper-level jet streak (purple area on 300 millibar map) plows through the region from west-to-east. As a result, in this type of dynamic atmosphere, “banding” is likely to develop in the precipitation field later today causing varying rates of precipitation and there could be an enhancement of the snow (or ice) in a given area in a short period of time. We’ll monitor the precipitation pattern as the day progresses and make adjustments to accumulation totals if necessary.

[Sunday AM 300 millibar winds showing powerful jet streak (purple) which is headed right into the Mid-Atlantic region; courtesy NOAA]

Another interesting and complicated threat at mid-week Another complicated precipitation event is likely to occur in the I-95 corridor from Tuesday into Thursday. Precipitation ahead of another strong Arctic frontal system is likely to arrive late Tuesday and it could start as a wintry mix in the I-95 corridor. However, as milder air pumps in from the south, the precipitation is likely to change to plain rain for Tuesday night and early Wednesday and some of the rain can be heavy. Temperatures could climb into the 50’s in portions of the I-95 corridor during the day Wednesday before colder air returns. The Arctic frontal system may then stall as it reaches the east coast on Wednesday night and there is a chance low pressure develops along the frontal boundary and rides up along it into the I-95 corridor region. If this takes place, it could very well turn cold enough for significant snow around here in the late Wednesday night/Thursday time frame. Stay tuned on that one.