>METEOROLOGICAL DISCUSSION: Major Snow/Ice Storm to mix with Frigid Arctic Air

To be honest with you, Easterners haven’t had too bad a time from old man winter this January but it looks as though the cold is ready to catch up and will produce a bone-chilling close to January 2010.

US-CANADA starting to get colder while Europe and Asia is Frigid

The US finally appears to be looking and feeling the air that’s driving severe cold and snow into much of Europe and Asia, the extent to this cold is remarkably large and intense with -20C air in central Europe with even -25 to -30C from Poland to the Ukraine and -30 to -45C across the heart of interior Asia from Kazakhstan to northern China, -50C cold is showing up in the heart of Siberia, remember this Asian continent is 3 TIMES LARGER than that of North America and therefore it gets even colder than northern Canada’s frozen wasteland.

The very tapping into Siberia vast reservoir of frozen air via a cross-polar flow will drive very cold air into the US in the coming days and weeks and as pressures build into the northern tier states and across the Eastern third, the air grows colder and colder as the Arctic high expands over most of the country “east of the Rockies”. The stratoshere is warming and this is evident in the nature of how the cold is despersing across the hemisphere. Remember most of Europe and Asia is beneath a blanket of cold, Arctic air now and here in the British Isles, we shall see colder and colder times as the westward advancement of this enormous cold pool pushes into us as we eneter February. I wouldn’t be suprised if Feb 2010 opens it’s first 10-day period as one of the coldest of all-time.

Eastern Snowstorm
Southern Plains to Mid-Atlantic

It will be from a storm system now crossing the Four Corners that will, once east of the Rockies will create havoc across the Plains over the next 24 to 36 hour period and eventually over the Appalachains and into the coastal plain of the Mid-Atlantic region which includes the Washington DC to Baltimore to Philadelphia urban corridor and may extend further north into the Greater NYC area and even Boston.

SPLIT FLOW

There are two different upper-level air flows within the US atmosphere, one from a NW direction which is transporting Arctic air into it’s trough which is down over the Northern Rockies, Northern Plains, Upper Midwest and into the Great Lakes and northern New England. The other flow is out of the W-SW and pushing milder, moister air in off the Pacific. The Arctic air is only dropping so far (central plains and up to northern New England and a push of mild air is unabstructed west to east from the Southwest all the way to New York. The colder air however is slowly migrating south and east as the Arctic high, aided by a trough deepening stratospheric warming and cross polar flow event as well as the progressive large-scale hemispheric pattern.

The area of low pressure will ride the “southern jet stream” east from Arizona through Texas on eastbound through Mississippi, Louisiana, Alabama on out towards South Carolina and the Atlantic Ocean.

As for the “northern jet stream” that’s over the Northern plains states will push southbound TOWARDS the warm, more energetic southern branch which of course is where the low is riding the tracks. Arctic high pressure sits above the Northern branch and southward moving Arctic air and a low getting pumped with milder, moisture laden air pushing in from the Pacific is ready to create havoc on the southern Plains as a major snowstorm which will be found across Oklahoma, Arkansas into the high country of the Carolinas and Virginias where anywhere from 1-2 inches to as much as 6-12 inches could be expected from this system. There may be locally 16 inch amounts as I wonder whether more moisture being pulling up from the Gulf by this system and the pulling southbound of the very cold air from Canada could produce greater snow amounts, particularly through orographic lift in the Appalachains and other upslope areas.

The High over the Midwest and New England will likely stop this low from turning up the East Coast and blasting New England with heavy snowfall, however DC to Baltimore and perhaps even up to Philadelphia may end up seeing a decent snowstorm out of this depending on where it’s track goes and whether it can nudge far enough north. I do see DC and Baltimore with at least 4 inches, Philadelphia 4″ and New York perhaps 1-2 inches, Boston may be spared with this.

The possibility however also lies with a further north progression of moisture up into the I-95 from DC and Boston and with all the cold air in place, we may see 4-8 in DC (locally a foot in places) up through Baltimore and Philly and 6 inches as far north of NYC and 4″ even up in Boston..