winter storm update, interesting day today

[WXBUFFJIM]

Good afternoon everyone. Definitely of significant impacts and snow isn't the only winter problem we're facing east of the Rocky Mountains. Another problem we're facing is the potential of a significant and widespread prolonged icestorm from the Ohio Valley and especially into the interior of the Mid Atlantic and northeast where power outages are likely with this. We also have to concern ourselves with widespread flooding since the potential exists for this freezing precip to change on over to rain, heavy at times. This is especially true for the lower Ohio Valley and into the Tennessee Valley and also into the Middle Atlantic States and the coastal areas of the northeastern United States. This is a complex situation, but serious impacts are anticipated.

Breaking this down first with the watches, warnings, and advisories for this day here http://www.spc.noaa.gov/products/wwa/

A winter storm warning is up for eastern Iowa and extending northeastward into Wisconsin and the UP of Michigan. In this area, snowfall will range from 3-6 inches with some areas, especially up in Wisconsin seeing locally higher amounts. South and east of that, we have a winter weather advisory up for St Louis, Kansas City, Chicago and for Indianapolis. There are also winter storm watches, warnings, and winter weather advisories up for the northern Mid Atlantic states and the northeast. Keep an eye on the New England coast this coming Saturday since the potential will exist of an explosive coastal low off New England coast on Saturday. This maybe overdone a bit according to the ETA model I'm gonna show you in a second. However should this bombogenesis verify, we'll see prolonged the precipitation, and increasing the winds, thus the potential of more power outages. However we gotta be careful with this. There is still a possibility that the coastal storm may not bomb out until it gets well north and east of New England. However we got to keep an eye on this trend for Saturday for the northeastern United States. If that wasn't enough, we also have a major flood threat for the southern United States and the Tennessee Valley, Ohio Valley, and the Middle Atlantic area where icy and snow covered rivers and ground combined with the heavy rain will create lots of runoff. As a result, ice jam and river flooding is likely, especially across the Mid Atlantic and into Ohio Valley. Further south into the southern United States, the flooding is likely simply due to too much rain falling in a short amount of time courtesy of strong thunderstorms. 3-5 inches of rain is possible in spots across the southern United States while widespread 1-2 inch amounts can be expected for areas along the Ohio river and extending eastward into the Middle Atlantic region, mainly in lower elevations. The following shows model depictions of this winter storm scenario.

ETA
http://www.nco.ncep.noaa.gov/pmb/nwprod ... p_006s.gif
http://www.nco.ncep.noaa.gov/pmb/nwprod ... p_012s.gif
http://www.nco.ncep.noaa.gov/pmb/nwprod ... p_018s.gif
http://www.nco.ncep.noaa.gov/pmb/nwprod ... p_024s.gif
http://www.nco.ncep.noaa.gov/pmb/nwprod ... p_030s.gif
http://www.nco.ncep.noaa.gov/pmb/nwprod ... p_036s.gif
http://www.nco.ncep.noaa.gov/pmb/nwprod ... p_042s.gif
http://www.nco.ncep.noaa.gov/pmb/nwprod ... p_048s.gif
http://www.nco.ncep.noaa.gov/pmb/nwprod ... p_054s.gif
http://www.nco.ncep.noaa.gov/pmb/nwprod ... p_060s.gif

GFS
http://www.nco.ncep.noaa.gov/pmb/nwprod ... p_006s.gif
http://www.nco.ncep.noaa.gov/pmb/nwprod ... p_012s.gif
http://www.nco.ncep.noaa.gov/pmb/nwprod ... p_018s.gif
http://www.nco.ncep.noaa.gov/pmb/nwprod ... p_024s.gif
http://www.nco.ncep.noaa.gov/pmb/nwprod ... p_030s.gif
http://www.nco.ncep.noaa.gov/pmb/nwprod ... p_036s.gif
http://www.nco.ncep.noaa.gov/pmb/nwprod ... p_042s.gif
http://www.nco.ncep.noaa.gov/pmb/nwprod ... p_048s.gif
http://www.nco.ncep.noaa.gov/pmb/nwprod ... p_054s.gif
http://www.nco.ncep.noaa.gov/pmb/nwprod ... p_060s.gif

Checking this out city by city, there are some heavier areas of snow to talk about. For example, Davenport and the Quad Cities area will likely see 3-6 inches of snow before all is said and done later today through tonight. Locally higher amounts are possible over Wisconsin. For instance Green Bay could see close to 6 inches. But not many areas will see more than that at this point.

Further south into Kansas City, bands of heavy snow have been occurring this afternoon over Kansas City. This will result in heavier amounts of up to 5 inches possibly in spots. Something to keep an eye on this afternoon. For St Louis, not as much snow or ice is occurring as anticipated. Thus a winter weather advisory is up now as opposed to a winter storm warning. That was downgraded to an advisory. However we must remember that even alittle bit of ice and snow will cause travel problems, especially as we approach evening rush hour and it gets dark.
Same can be said for Chicago where a 3-5 inch snow is possible with less than 3 inches south of the city as we mix over with sleet and freezing rain. Still some travel problems and worth slowing down in these type of conditions.

Meanwhile we run into the area where the most ice could accumulate from this storm and that will be the northeastern United States for interior areas only. 1/4 inch of ice is likely northwest of Baltimore, DC, and Philadelphia. Areas of western PA and into central and northern PA including State College could see over 1/2 inch of damaging ice accumulation late tonight and into Friday. The big cities along I 95 from NYC to DC will quickly change over to rain. This rain combined with snow and ice melt will result in possible ice jams and river flooding. Also with clogged storm drains courtesy of the snow, street flooding and road closures are possible. Please do not drive through flooded roads. It's way too dangerous as most flooding deaths occur when a person drives through a flooded road and get swept to their deaths basically. We want to avoid that problem.

Also keep a close eye on New York State and into north central New England where an icestorm is expected to produce over 1/2 inch of ice from Albany to Concord. Areas north of that could see a significant snow including the green an white mountains. But we must also keep in mind, if we see a coastal storm bomb out Saturday along the coast along that stalled out frontal boundary, then it gets even more interesting. We gotta watch that carefully and you should as well if you live in the northeastern US.

More updates will follow.

Jim

[yoda]

Nice discussion.... yes, I am looking for 1-2 inches of rain here... but maybe some icing first....

[JCT777]

Great update, Jim. Thanks!

[sertorius]

Again Jim, awesome job!! Thanks so much-the Lawrence/Kansas City area really had this storm blow up ontop of them-about time!!! The radar last night looked down right meek-but man this morning, some heavy bands kept developing and we've had heavy snow for about 5 hours!! The roads are just a mess!!!