Here we go, folks.
Our storm (named “Jonas”) is taking shape over north Texas. All signs are there. There will be a crippling blizzard for inland regions of North Carolina, Virginia, and West Virginia, and in addition, a crippling blizzard for Baltimore-Washington possibly through to New York City. Boston, you may be in the clear but stay tuned. Meanwhile even Charlotte, Raleigh, Greensboro and Atlanta will be in the game, along with Nashville back to Memphis. Ice is the main threat here in central North Carolina , with heavy snow in the Smoky Mountains (I do know there are few of y’all out there who post from that region. Please be safe!)
Severe weather too, is a feature. It will be nasty across Florida. The thing about storms like these in the winter is they bring severe weather to the areas not receiving snow. As I write this, tornado watches are up across Texas and Louisiana, and tornadoes are breaking out across east Texas.
Let’s also not forget the full moon on Saturday. Portions of the New Jersey and Delaware coast will experience storm surges that may exceed the surge bought by Hurricane Sandy. The towns that border Delaware Bay may see significant flooding over multiple tide cycles.
This is the real deal. Even the Hurricane Hunters are about to fly.
Tomorrow, snow and ice will break out across the Southeast after tonight’s severe weather forecast to blow through this evening. If you live in or near Birmingham, Atlanta, Charlotte, Memphis and Nashville, perhaps as far south as Jackson, stay home if you can. If you live in and around Charlotte up through Greensboro---ice is a serious threat here, up to an inch of it accumulating. On top of that, up to 8” of snow may fall in Durham, NC—on top of the ice! Ice will fall back through most of Kentucky, up to a half-inch. Ice is scarier than snow, for me. This means power outages and significant damage to electrical infrastructure.
Severe weather will break out across Florida and southern Georgia on Friday, with a fairly significant chance of isolated tornadoes. Tomorrow morning will be very ugly.
Snow should begin to fall in Washington DC around lunch time. Already seeing that most things will be closed tomorrow in the District. Stay home if you can, because as Friday evening goes on the storm (Jonas) will emerge off of the coast and rapidly intensify. This process is called Bombogenesis.
Bombogenesis is defined as a mid-latitude cyclone that drops in surface barometric pressure by 24 or more millibars in a 24-hour period. The height contours pack around the center of rotation and the number of height contours increases rapidly in the developing stages. The most common time of the year for bombogenesis to occur is in the cool season (October to March) when the temperature gradient is large between the high and mid-latitudes. Bombogenesis typically occurs between a cold continental air mass and warm ocean waters or between a cold polar air mass and a much warmer air mass. Many Nor-easters are the product of bombs.
This is what will cause the winds to rise (and the seas to rise) as the storm slowly moves northeast. By Saturday night, winds will gust higher than tropical-storm force in Washington DC, and may approach hurricane-force in cities like Lewes, DE and Atlantic City, NJ.
“Jonas” is linked to the subtropical jet, which this year is very strong due to El Nino. It is packing an immense amount of moisture, which will fall as snow. Coupled with the warm Atlantic (compared to last winter, it’s quite warm), it means a lot of snow.
WHAT IS A BLIZZARD?
A blizzard is pretty simple in the textbook (it’s often used incorrectly- the Blizzard of 1996 really wasn’t a blizzard). But simply put, the definition of a blizzard is:
The National Weather Service defines a blizzard as a storm which contains large amounts of snow OR blowing snow, with winds in excess of 35 mph and visibilities of less than 1/4 mile for an extended period of time (at least 3 hours). When these conditions are expected, the National Weather Service will issue a "Blizzard Warning". When these conditions are not expected to occur simultaneously, but one or two of these conditions are expected, a "Winter Storm Warning" or "Heavy Snow Warning" may be issued.
Blizzard conditions often develop on the northwest side of an intense storm system. The difference between the lower pressure in the storm and the higher pressure to the west creates a tight pressure gradient, or difference in pressure between two locations, which in turn results in very strong winds. These strong winds pick up available snow from the ground, or blow any snow which is falling, creating very low visibilities and the potential for significant drifting of snow.
That is what’s going to happen tomorrow night through Saturday in Washington DC and Baltimore.
This will be a long-duration event. The snow will end late on Saturday into Sunday.
COASTAL FLOODING
Coastal flood watches are up for Delaware and New Jersey.
Widespread moderate to major coastal and back bay flooding is expected along the Delaware and New Jersey coasts (except Monmouth County) this weekend, including Delaware Bay . A strong onshore flow will persist through three tide cycles. A Coastal Flood Watch is in effect for these areas for late Friday night through Sunday morning. Flooding is not expected along the Chesapeake Bay north of Cambridge.
LOCATION TIME OF PREDICTED WATER LEVEL
HIGH TIDE
SEASIDE HEIGHTS, NJ 6:30 AM SATURDAY NEAR 7.0 FEET MLLW
(OCEANFRONT) 6:58 PM SATURDAY NEAR 7.5 FEET MLLW
7:14 AM SUNDAY 7.5 TO 8.0 FEET MLLW
ATLANTIC CITY, NJ 6:43 AM SATURDAY NEAR 7.0 FEET MLLW
(OCEANFRONT) 7:09 PM SATURDAY NEAR 7.5 FEET MLLW
7:26 AM SUNDAY 7.5 TO 8.0 FEET MLLW
CAPE MAY, NJ 7:17 AM SATURDAY 7.5 TO 8.0 FEET MLLW
(OCEANFRONT) 7:43 PM SATURDAY NEAR 8.0 FEET MLLW
8:00 AM SUNDAY NEAR 8.5 FEET MLLW
LEWES, DE 7:59 AM SATURDAY 7.5 TO 8.0 FEET MLLW
(DELAWARE BAY) 8:22 PM SATURDAY 7.5 TO 8.0 FEET MLLW
8:42 AM SUNDAY NEAR 8.0 FEET MLLW
REHOBOTH BEACH, DE 7:00 AM SATURDAY NEAR 7.5 FEET MLLW
(OCEANFRONT) 7:13 PM SATURDAY NEAR 7.5 FEET MLLW
7:45 AM SUNDAY 7.5 TO 8.0 FEET MLLW
Some of these approach Hurricane Sandy levels. For NYC to Atlantic City, NJ, it looks like coastal flooding will be minor. But for areas between Ocean City MD and Atlantic City NJ, this could be a major event. Stay tuned, and be ready to evacuate.
SNOWFALL TOTALS
Snowfall through Sunday, by city
CITY |
AMOUNTS |
Boston |
probably not more than 6” |
NYC |
possibly up to 12”—very sharp cutoff, so very tricky. |
Philadelphia |
12-18” |
Baltimore |
possibly up to 24”, blizzard conditions Saturday |
Washington DC |
possibly up to 28”, blizzard conditions Saturday |
Richmond |
possibly up to 12” |
Charlotte |
5”-8”, serious, serious ice |
Atlanta |
1”-2”, ice too |
Please keep in mind this isn’t all that cold a storm Watch the rain-snow line closely. I think it may come inland a good way. In the DC area, there may be pretty wide differences in snowfall totals in the usual places because of this, and the same with Philadelphia. And it’s not going to last---this isn’t like the last couple winters where brutal cold hung around for weeks. We’ll be back to seasonal to warmish temps by the end of next week.