This is not a drill.

This is not a drill.

DANGEROUS AND HIGH IMPACT STORM TO AFFECT

ENTIRE MID-ATLANTIC AND NORTHEAST CORRIDOR 
FRIDAY INTO SUNDAY WITH HEAVY SNOW & STRONG WINDS

BLIZZARD WATCH POSTED FOR PORTIONS OF BALTIMORE / 
WASHINGTON METRO - NORTHERN VIRGINIA & SOUTHERN MD

• SUSTAINED WINDS OF 40 MPH OVER A 12-HOUR PERIOD OR MORE WILL PRODUCE SIGNIFICANT POWER OUTAGES AND LOW VISIBILITY, MAKING TRAVEL IMPOSSIBLE IN AFFECTED AREAS.

• MAJOR COASTAL FLOODING EXPECTED ALONG THE ATLANTIC SHORE, STORM SURGES OF 3-5 FEET PROJECTED FOR COASTAL MD - DE - NJ. 

• BLOWING AND DRIFTING OF SNOW IN NORTHERN AREAS OF THE WATCH WHERE SNOW RATIOS WILL BE HIGHER DUE TO COLDER TEMPS.

• TEMPERATURES IN THE 20S DURING AND AFTER THE STORM WILL CREATE REFREEZING OF ANY AREAS CLEARED OF SNOW.

WINTER STORM SAFETY RESOURCES

Visit NOAA Winter Storm Safety Page for more details

"Your primary concerns at home or work during a winter storm are loss of heat, power and telephone service and a shortage of supplies if storm conditions continue for more than a day." - NOAA

In either place, you should have available:

• Flashlight and extra batteries
• Battery-powered NOAA Weather Radio and portable radio to receive emergency info 
• Extra food and water such as dried fruit, nuts and granola bars, and other food requiring no cooking or refrigeration.
• Extra prescription medicine
• Baby items such as diapers and formula
• First-aid supplies
• Heating fuel: refuel before you are empty; fuel carriers may not reach you for days after a winter storm
• Emergency heat source: fireplace, wood stove or space heater, properly ventilated to prevent a fire. NOT CANDLES OR INDOOR KEROSENE heaters
• Fire extinguisher, smoke alarm; test smoke alarms once a month to ensure they work properly
• Extra pet food and warm shelter for pets
• Review generator safety. You should never run a generator in an enclosed space.
• Home fires are common each winter when trying to stay warm. Review ways to keep your home and loved ones safe so you don't become an unnecessary headline. (FF)

WHERE IS THE STORM? The stream of energy rising from the Gulf of Mexico will be pulled into
that approaching band of activity in the Southwest to form a new low in the Southern Plains today.

6:30 AM EST 1/20 HIGH CONFIDENCE FOR MAJOR MID-ATLANTIC STORM FRIDAY INTO SUNDAY. (Forecaster Mike & the Winter Stormcast Team) Brisk and wintry greetings everyone! Shades of snowstorms past are appearing in this upcoming winter storm expected for Friday into Saturday. We are certain now that it is going to snow, the question is, how much? 

While we are seeing similarities to many of our high impact snowstorms of notable years, like February 2010, February 2003, and January 1996, the track is not set in stone yet. Since we are three days out still, there is time for things to change. However, it is rare to have this confidence this far in advance, and many factors could impact the timing and areas of heaviest snow.

For now, we have the scenarios we think are most likely to play out this weekend. As is our standard approach, tracing back to our coverage of the 2010 storms, we present a range of options from worst case to most disappointing and use models as guidance - not gospel - to inform our assessment of what is the most probable ground truth we all may see. See below the map for the scenarios.

SCENARIO A: 60% Chance – The Big Kahuna 

Have you been waiting since February 2010 for the next big storm? This scenario brings snow totals of nearly one foot or even more to much of central and western Maryland, northern/western Virginia, and West Virginia. 

• The impact of this storm has the potential to surpass February 12-13, 2014, the Mid-Atlantic's last major snowfall. 
• Combined with high winds, travel would be difficult to impossible for 36 hours starting when snow begins between late morning Friday and mid afternoon. 
• Heavy snow continues overnight, and tapers Saturday afternoon. The map below from the US Global Forecast System shows surface pressure and precip as of 1 PM Saturday 1/23.

While this isn’t a lock yet, we do think it is the most likely scenario at this point, with a 60% probability of playing out. But weather is an inexact science, so here is how this could change. 

SCENARIO B: 25% Chance – Southern Special 
Contrary to Scenario C, cold air remains strong and the high pressure to our north prevents a weaker low pressure system from moving north. 

• The result is the storm gets pushed out to sea and to the south. This would deliver a major snowstorm to parts of Virginia and North Carolina as well as into the southern Appalachians. 
• The major cities of DC, Baltimore, Philadelphia, New York, and Boston would be spared from the worst of the storm. 
• The metro areas and those to the north would be under a very sharp cutoff of snow accumulation totals as you go north. 

SCENARIO C: 15% Chance – Wintry Slop 
This scenario would occur if the low pressure system tracks further north and closer to or along the Atlantic coastline. 

• After the warm end to 2015, water temperatures are extremely warm in the Chesapeake and the Gulf Stream, compared to normal for this time of year. 
• A low closer to the coast would surge warm air into the I-95 corridor, and switch snow to a wintry slop of snow, sleet, and then rain overnight Friday into Saturday. 
• Snow accumulations would be significantly less, but still near 6" for those NW of the cities, while the cities get more slop. 
• The bulls eye here is shifted away from central Maryland/northern Virginia, and into the Appalachian Mountains, the Blue Ridge, and up into Pennsylvania. 

What's the word for now? All data points to it being very likely (95%) that we much of the Mid-Atlantic will see snow accumulation, but remember that this far out in time, higher snow totals you may have seen on snow maps may have lower probabilities of occurring. If we see major snow becoming even more likely, we will continue updating you and share accumulation forecasts when confidence is high enough to present specific numbers publicly. 

If you need more detailed access to snowfall probabilities, and would like to receive advance internal reports by text, email and Smartphone, please consider registering as an Insider. A few readers already have and they are, shall we say, well in the know...well before the snow. We hope to see you there!

The FF Winter Stormcast Team

Contributors included Forecasters Connor M., Jason M., Troy A., Mike N., Joey K., Mintong N., Jake S., Meteorologists Jolene W., Pete W., Advisors Foot and Krichinsky