7:00 AM | Turns milder for the next few days, but colder air is on the horizon

6-Day Forecast

Today

Clouds give way to some sunshine, milder, highs in the low 50’s

Tonight

Partly cloudy, cold, lows by morning in the upper 30’s

Wednesday

Mostly cloudy, mild, chance for showers, mid 50’s

Wednesday Night

Mostly cloudy, cool, chance for showers, upper 40’s

Thursday

Mostly cloudy, mild, chance for showers, low 60's

Friday

Mostly cloudy, cooler, showers likely, mid 50’s

Saturday

Mostly cloudy, colder, chance for morning showers, near 40

Sunday

Mostly cloudy, cold, chance for ice, rain and/or snow, mid 30’s

Discussion

An incredibly cold Arctic air mass will plunge today towards the Rockies and Northern Plains and it eventually could contribute to problems here in the Mid-Atlantic region. A front will cross our region by Friday and then stall out in a southwest-to-northeast fashion this weekend. This will allow for several waves of low pressure to head in our direction along the frontal boundary zone and it could get cold enough for ice or snow later this weekend or early next week. Meanwhile, parts of the Northern Plains and Rocky Mountain States will suffer through a couple of days with sub-zero highs to go along with wind and accumulating snow.

Video

httpv://youtu.be/LhKH3bTmDMM

2:30 PM | *An incredibly cold Arctic air mass to cross country this week and it could eventually lead to problems in the Mid-Atlantic region*

Discussion

The calendar has turned to December and the signs are there for a very winter-like pattern across much of the nation during the next couple of weeks – the likes of which we haven’t seen in quite some time for this early in the winter season. An incredibly cold Arctic air outbreak is now gathering itself just above the US/Canada border region in southwestern Canada and it is about to plunge into the Northern Plains and Rocky Mountain region with painful results and temperatures some 40 degrees below normal. Temperatures by Wednesday and Thursday won’t rise above zero in parts of North Dakota and Montana and overnight lows could bottom out at 30 degrees below zero (GFS surface temperature forecast map for Thursday evening courtesy weather.cod.edu). Denver will experience plunging temperatures on Tuesday and might not be able to climb above 10 degrees on Wednesday and Thursday. To make matters worse, snow and wind will accompany this Arctic blast across the Rockies and Northern Plains during the next 48 hours or so.

This Arctic blast will continue on a trek towards the eastern states and could lead to potential problems for the Mid-Atlantic region. The initial cold front will likely pass through the Mid-Atlantic region by Friday or so, but it will then get hung up in a southwest-to-northeast direction not far from the east coast. At the same time, an active pattern may then produce wave-after-wave of low pressure that will ride along the frontal boundary from the moisture-laden Deep South towards this region. This type of pattern could ultimately lead to significant ice around later this weekend or early next week or even accumulating snow. There are signs for a second Arctic blast next week that will again affect much of the country. Stay tuned.

7:00 AM | A milder week to begin the month of December

6-Day Forecast

Today

Mostly cloudy, chilly, highs near 50 degrees

Tonight

Mostly cloudy, cold, lows by morning in the mid 30’s

Tuesday

Partly sunny, a bit milder, low 50's

Tuesday Night

Partly cloudy, cold, mid 30’s

Wednesday

Mostly cloudy, mild, mid 50's

Thursday

Mostly cloudy, milder, chance for showers, near 60

Friday

Mostly cloudy, cooler, chance for showers, near 50

Saturday

Mostly cloudy, even colder, chance for showers, low 40’s

Discussion

A storm will develop off the Carolina coast later today and then intensify as it moves northeastward off the New England coast on Tuesday. This storm will contribute some to our cloud cover into tomorrow; but its precipitation shield should stay east of here. Strong low pressure in the upper Great Lakes should move towards southeastern Canada sending a cold front our way later this week. Meanwhile, as far as Comet ISON is concerned, it appears as if it did not survive its encounter with the sun's atmosphere on Thanksgiving Day and is now nothing more than a cloud of dust...so much for the "Comet of the Century".

Video

httpv://youtu.be/odRpvhHcTBU

7:00 AM | Way below normal temperatures for Thanksgiving Day; Comet ISON makes its closest approach to the sun today

6-Day Forecast

Today

Mostly sunny, very cold, winds may be gusty early in the day, but should slacken off quickly by this afternoon, highs in the low-to-mid 30’s

Tonight

Mostly clear, very cold, light winds, lows by morning in the low 20’s

Friday

Mostly sunny, very cold, light winds, mid-to-upper 30’s

Friday Night

Mostly clear, very cold, near 25

Saturday

Mostly sunny and still very cold, mid-to-upper 30’s

Sunday

Mostly cloudy, not quite as cold, but still below normal, low-to-mid 40’s

Monday

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

Tuesday

Partly sunny, cool, near 50

Discussion

As yesterday’s storm pulls farther away into southeastern Canada, high pressure will build into our region from the Midwest and today will feature plenty of sunshine; however, temperatures will be way below normal for this time of year struggling to rise much past the freezing mark. Winds will start the day on the strong side out of the northwest, but as high pressure builds in overhead, the winds should drop off quickly this afternoon and evening. Colder-than-normal weather will continue on Friday and Saturday with sunshine each day and light winds. Meanwhile, Comet ISON will make its closest approach to the sun today and we’ll have a much better idea on Friday as to whether it will still be able to put on a great viewing show for us during the month of December.

1:50 PM | Rain to change to sleet, snow later this afternoon as Arctic air pours in

Discussion

As Arctic air pours into the Mid-Atlantic region, the lingering rain activity will change over to sleet and then snow later this afternoon from northwest-to-southeast and a snow shower threat will continue right into the overnight hours. Temperatures should keep dropping through the 30’s during the rest of the afternoon and will bottom out well below freezing late tonight so there may be some icing that forms on roadways rather quickly this evening as temperatures drop sharply. There is a chance for minor snow accumulations from later this afternoon through late tonight as a secondary low pressure system area rides up the east coast.

7:00 AM | As major storm pulls to our northeast an Arctic blast will arrive with strong winds, falling temperatures and possible snow showers

6-Day Forecast

Today

Occasional rain showers into the early afternoon with strengthening northwest winds, rain showers should change to snow by late afternoon, temperatures have already peaked for today and will steadily drop to the low-to-mid 30's by the end of the day

Tonight

Windy and much colder with possible snow showers, lows by morning in the low-to-mid 20’s

Thursday

Mostly sunny, very cold, strong winds in the morning will slacken off during the afternoon, low-to-mid 30’s

Thursday Night

Mostly clear, very cold, light winds, low 20’s

Friday

Mostly sunny and still very cold, mid-to-upper 30’s

Saturday

Mostly sunny, very cold, upper 30’s

Sunday

Mostly sunny, not quite as cold, but still below normal, low-to-mid 40’s

Monday

Mostly cloudy, chilly, maybe a few showers, upper 40’s

Discussion

The major storm that generated heavy rain overnight will shift to our northeast today and Arctic air will pour into the region on strengthening northwest winds. Temperatures have already reached their peak for the day and will steadily drop into the 30's by afternoon. The morning steadier rainfall will give way to rain showers that should changeover to snow by late in the day. Strong northwest winds will continue tonight and the snow shower threat will continue with minor accumulations possible between late afternoon and late tonight. Temperatures by morning will be way down in the 20's so all ground surfaces will experience a freeze. Thanksgiving Day promises to be well below normal for this time of year with highs holding in the low-to-mid 30's. Winds will continue to be quite strong out of the northwest during the morning hours on Thursday, but should slacken off during the afternoon and evening as high pressure quickly builds in overhead. The colder-than-normal weather will continue on Friday and Saturday as well and the winds will stay on the light side. Finally, expect a couple inches of turkey to accumulate late tomorrow afternoon or early evening and that will likely diminish to sandwiches on Friday.

Video

httpv://youtu.be/YpjU5PB03yc

1:00 PM | Update on the major storm...a significant rain and wind event followed by an Arctic blast

Discussion

Our major pre-Thanksgiving Day storm is now underway along the I-95 corridor with rain currently falling from the DC metro region to New York City. Atmospheric ingredients are coming together for a substantial rain and wind event up and down the I-95 corridor from DC to Boston over the next 24 hours or so. This entire region should receive 2-4 inches of rainfall from this storm and potentially damaging wind gusts between later tonight and early Thursday. To make matters worse as far as the winds are concerned, they will be quite strong from two different directions during the storm - which never helps the trees - as they will become quite strong tonight from the southeast-to-east and then strong later tomorrow and tomorrow night out of the northwest. Thunderstorms could also mix into the picture; especially, along coastal locations from New Jersey southward. A powerful jet streak in the upper atmosphere is combining with a well-established and “reluctantly-retreating” cold Arctic air mass and northward-moving tropical moisture from the Gulf of Mexico to generate an intensifying low pressure system that will ride up the eastern seaboard over the next 24 hours.

The rain began briefly as a mixture of sleet and rain in some suburban locations to the west and north of DC and Philly, but plain rain should fall from this afternoon into tomorrow morning and the rain will become very heavy at times. Temperatures are just slightly above freezing in many Mid-Atlantic locations at the current time, but they should actually rise throughout the night as strong southeast-to-east winds pump in milder air from the Atlantic Ocean. Once the strong low pressure system pulls to our northeast on Wednesday, a powerful Arctic front will blast through the Mid-Atlantic region causing temperatures to plunge, winds to shift to a northwesterly direction, and lingering rain showers will quite likely change to snow showers in the I-95 corridor. Powerful winds will continue through tomorrow night in the Mid-Atlantic region as the next Arctic air mass pours into the area. Arctic cold will grip the entire region on Thursday, Thanksgiving Day.

[Total precipitation amounts for this upcoming event from the latest NAM computer forecast model run with a stripe of 3+ inches of rainfall between DC and Boston]

7:00 AM | **Major storm rides up the eastern seaboard; heavy rainfall could end up in the 2-4 inch range by tomorrow**

6-Day Forecast

Today

Cloudy with rain developing this morning, there could be a brief period of mixed frozen precipitation at the onset west and north of the District, rain becomes heavy at times this afternoon, chilly, highs near 40 degrees

Tonight

Rain, heavy at times, maybe a thunderstorm mixed in, becoming very windy, temperatures holding steady or rising into the 40's

Wednesday

Cloudy with more rain during the morning, very windy, temperatures drop during the afternoon hours and lingering rain showers could change to snow shoers, highs in the 40's reached early in the day

Wednesday Night

Partly cloudy with snow showers possible, continued strong winds and turning colder, upper 20’s by morning

Thursday

Mostly sunny and very cold, strong winds in the morning that will slacken off during the afternoon and evening, low-to-mid 30’s

Friday

Mostly sunny, still very cold, mid-to-upper 30’s

Saturday

Mostly sunny, cold, near 40

Sunday

Partly sunny, not quite as cold, but still below normal for this time of year, low-to-mid 40’s

Discussion

A major storm will ride up the eastern seaboard over the next 24 hours and it will bring the I-95 corridor region from DC to New York City heavy rainfall that may end up in the 2-4 inch range by midday tomorrow as we go from drought-like conditions to flood-like in quite a hurry. There may be enough cold air around early this morning to allow for a brief period of sleet, snow and/or freezing rain at the onset of the precipitation event to the west and north of the District, but plain rain is likely by this afternoon as slightly milder air pushes in and it will become heavy at times. Heavy rainfall will continue tonight up and down the I-95 corridor and there can be a few thunderstorms mixed in. Winds will increase noticeably tonight out of the south or southeast pumping in even milder air and temperatures will likely rise into the 40's by early Wednesday. As the storm pulls away later tomorrow, another batch of Arctic air will move into the Mid-Atlantic region, temperatures will drop quickly, and lingering rain showers could change to snow showers accompanied by strong northwest winds. Thanksgiving Day promises to be very cold with well below normal temperatures for this time of year and strong northwest winds in the morning hours; however, the winds are likely to slacken off during the afternoon and evening as high pressure edges overhead.

Video

httpv://youtu.be/UoMD6NGZemk

12:45 PM | The day of reckoning has come for Comet ISON

[Image courtesy spaceweather.com taken yesterday from the Canary Islands, eastern Atlantic Ocean]

Discussion

On Thursday, Thanksgiving Day, Comet ISON will make its closest approach to the sun flying through the sun’s atmosphere little more than a million kilometers above the solar surface. At closest approach, the core of ISON could rise by as much as 5000° Fahrenheit – a life or death challenge for an icy comet. No one knows if it will survive.

But if ISON makes it out alive, it could provide a great show to the naked eye and possibly even live up to its billing as the “Comet of the Century”. On Friday, professional and amateur astronomers will be searching for the comet as it comes around the sun and then between Thanksgiving and Christmas, it will fly over the North Pole – potentially, a very nice holiday comet.

What makes ISON quite special is that it is a lone traveler originating from a giant population of comets at the very edge of the solar system – the furthest reaches of the sun’s gravity. The distance from the Earth to the sun is an “astronomical unit” or AU. Pluto, as an example, is 40 AU from the sun. Comet ISON began its journey 100,000 AU away from us in a place called the Oort cloud which contains billions of icy, rocky objects. Detected comets from the Oort cloud are quite rare – probably only a handful per century.

For all of human history – at least a million years according to NASA – this comet has been heading towards the sun. We’ll know beginning this Friday, after coming within a hair of the sun, if Comet ISON survives and is ready to put on a great show for us during the month of December.

7:00 AM | **Coldest November day since 1987**; Thanksgiving week brings us a major storm with heavy rain and then another Arctic outbreak

6-Day Forecast

Today

Mostly sunny, still quite cold for this time of year, but without the wind, highs in the upper 30’s

Tonight

Mostly cloudy, cold, lows near freezing

Tuesday

Cloudy, cold, chance for rain, sleet or snow in the morning and then rain, heavy at times during the afternoon,

Tuesday Night

Cloudy with rain, heavy at times, temperatures holding steady or rising

Wednesday

Cloudy, more rain likely, but then as colder air moves in late snow showers will be possible, mid 40's reached early

Thursday

Mostly sunny, windy and very cold, mid-to-upper 30’s

Friday

Partly sunny, still very cold, upper 30’s

Saturday

Partly sunny, cold, near 40

Discussion

Yesterday's high temperature at Reagan National Airport was only 34 degrees - some 21 degrees below normal for this time of year and the coldest November day since 1987. Philly Airport actually recorded their lowest November temperature in 24 years (1989) with a record low reading of 20 degrees.

Two major weather stories this week: 1) a significant storm will move from the Gulf of Mexico region up the eastern seaboard and bring with it the possibility for 2-4 inches of rainfall to the big cities along I-95 2) another Arctic outbreak will reach the Mid-Atlantic region by Turkey Day. This could very well turn out to be one of the coldest Thanksgiving weeks on a nationwide basis in many, many years. As far as the upcoming storm is concerned, the bulk of it should be in the form of rain around here and there will certainly be heavy rain involved; especially, during Tuesday afternoon and night. While the majority of this event will be rain around here, it could be just cold enough at the onset on Tuesday for a brief period of mixed frozen precipitation and then, as colder air pours in on the back end of the storm later Wednesday, there could be some snow shower activity along with some very strong winds. Thursday, Thanksgiving Day, will feature more bitter cold Arctic air for this time of year and the winds will be quite strong; especially, during the morning hours.

Video

httpv://youtu.be/eAsY8gJQzNU