Winter storm update, could see blizzard conditions in spots.

[WXBUFFJIM]

Good evening everyone. Definitely a busy winter storm setup and a complex pair of storm systems that will make travel hazardous and in some cases impossible in some locations Friday right through Sunday. Timing brings wintry wx into DC and Baltimore tonight around midnight and Philly during the day on Friday. But this is only part 1 of a 2 part storm. The 2nd part is forecast to be even more intense for the I 95 corridor from DC up to Philadelphia with snow and wind gusts near blizzard criteria. Further north into New York City and Boston, the majority of the winter storm will hit in those areas Friday night and last through early Sunday. Snow and very gusty wind combined will result in whiteout conditions and a better chance of blizzard conditions for the tristate region and into southern New England as well.

Right now we have a winter storm warning in effect from Baltimore and Washington DC on north and west due to the anticipation of 3-6 inches of snow tonight. Communities included in the winter storm warning area include Westminster, MD, Martinsburg, WV and Hagerstown, MD. A winter storm warning means severe winter weather such as significant snow and or ice is expected in the warned area or is immient. Meanwhile a winter weather advisory is in effect for Baltimore City, Washington DC, and Philadelphia tonight through Friday morning. Snowfall amounts of 2-4 inches is expected with some sleet and rain mixed in at times on Fridat before tapering off temporarily. A winter storm watch is in effect for Washington DC, Baltimore, Harrisburg, Allentown, Philadelphia and New York City Friday night through Saturday. A winter storm watch is also in effect for Boston, which lasts through early Sunday. Significant snowfall accumulations of 6-12 inches with locally higher amounts in heavier mesoscale bands are likely in all the major cities Friday night through Sunday morning. In addition to the snow, very strong winds could mean blizzard conditions and very high snow drifts. That could make travel almost impossible and it maybe just that for the weekend for the major cities. This is a storm that has the potential of being a bigger and more crippling snowstorm than the December 5th, 2002 storm was. There will definitely be alot of staying power as further information becomes available on this potentially dangerous storm.

Now the real question is what is causing this problem? Part 1 of this storm is developing off the carolina coast with cold air wedging down the east side of the Appl. Mountains. The end result in wintry precip for DC, Baltimore, and Philadelphia tonight with higher snowfall amounts just north and west of those cities overnight tonight and into early Friday. Cold high pressure will also dominate our weather bringing down the colder air from Canada. By midday and early afternoon Friday, the potential of a lull in the action will be short lived as low pressure forms on the Mid Atlantic coast and slowly tracks northeast as an upper disturbance slams into that developing coastal storm. Thus the entire system will become more energized and become a potentially crippling storm from DC up to Boston with significant snows and wind gusts strong enough to create whiteout conditions. Near blizzard conditions are likely Friday night through Sunday in the megalopolis.

As the coastal storm intensifies Friday through Saturday, there will be more significant snowfall and colder air will dive southward courtesy of strong high pressure over eastern Canada. Even the coastal sections from the jersey shore down through the delmarva Peninsula and the tidewater will likely see rain changeover to snow Saturday and the snow will last into Saturday night even on the coast. However gusty winds combined with the snow will result in possible blizzard conditions, even on the coastal sections of the mid atlantic and especially into New England. Gale and storm warnings are up along the new england and mid atlantic coastal areas. Tides are expected to be several feet above normal. The combination of this intense coastal storm combined with the astronomically higher than normal tides courtesy of the December 8th full moon will enhance the risk of major beach erosion and coastal flooding along the coastal areas. Definitely a very strong storm system and folks in the mid atlantic and the northeastern United States including the megalopolis and the coastal areas should prepare for this potentially dangerous winter storm over the next day or so. After Friday, all bets are off in the megalopolis.

Elsewhere across the country, the upper disturbance, which will fire up the coastal storm is currently over the northern plains and midwestern United States. Snow advisories and winter weather advisories are in effect in many areas of the northern plains and midwest. Snowfall is expected tonight through Friday for Des Moines, the Quad Cities, Chicago, and eventually into Indianapolis as well. Snowfall accumulation of 2-5 inches is expected in these areas tonight through Friday. Locally higher amounts are possible in more concentrated heavier mesoscale bands. So even the midwest and northern plains will get a nail biting effect from this storm also.

I will post another update on this storm overnight and early Friday am. Stay safe everyone!!!

Jim

[rainstorm]

anything here?

[wxid]

As usual, nice breakdown Jim!

[li-mike]

I have been saying it a bit on the WWBB but the trick is in these coastal storms to be close to the RN/SN line but not get caught in the mixing. I think we will do fine tomorrow on Northern LI. Temps are well below progged (25.7 degrees at 726pm) and if we can time this right the maximum radiational cooling will occur with my temps dropping to the High Teens or low 20's tonight then the cloud cover comes in-b4 sunrise and there you have it no way for the cold to escap with the sun. either way we get a lot of snow here I say 4-8 Inches in worst case and best case will be near 15 inches and that would be historical. Thank you all for your forecasts and attention to detail.

Li-Mike living on the North shore in the Pine Barrens.

[Stephanie]

It's amazing how these accumulations have gone from 0 - 6 or 8 inches in just one day!