Meteorological Sketch of the February 9-13, 1998 "Stagnation Episode"

Submitted by Doc Taylor, NY DEC

On the 8th, the upper level pattern (500 mb) was characterized by a remarkable split flow with the southern jet down across TX to FL, and ridging across the Great Lakes. At the sfc there was high pressure extending from the Great lakes to the Northeast. Pretty strong press gradient along the coast due to an ocean storm well offshore.

On the 9th, 500 mb ridging moved east to NY and New England, with the sfc high centered over NY. 12z Albany sounding was pretty stable (-7 at the sfc and -1 at 850 mb). Sfc obs from Albany showed winds basically calm all day an into the night.

On the 10th, 500 mb heights highest along the East Coast, with a sharp trof in the southern branch initiating cyclogenesis in TX. Sfc ridge nosed down along the coast from ME to VA. 850 mb ridge from southern Tier of NY to VA. Once again 12z sounding from Albany quite stable with sfc at -6 and 850 mb +2. Winds very light from sfc to 850 mb(1 kt). Afternoon sfc map showed sfc high had moved off shore of Cape Cod (southeast sfc flow over eastern New England). Albany sfc winds went light southerly during the day.

On the 11th 500 mb heights continue to rise in response to a major trof ejecting out of the lower Mississippi Valley. Sfc high pressure just off shore, with 992 low tracking northward out of southern MO. At the 850 mb level southwest flow taking hold over the northeast with winds about 10 - 15 kts. Alb 12z sounding still stable, but not as much so as before with sfc at 0 and 850 temp at +2. The afternoon wx map showed the low moving into IL with high clouds spreading into central NY. Relatively light south winds were the rule in New England, while increasing southeasterly winds began to affect western and central NY.

On the 12th, the upper level trof was swinging through the northeast. The sfc low was tracking down the St. Lawrence. Southern New England popped into the warm sector with strong southerly winds while areas in central New England still had light winds ahead of the warm front. The 850 mb low also tracked down the St. Lawrence, with screaming southerly flow over eastern areas. The 12z Alb sounding showed multilayered inversions up to 850 mb. By 3 pm the cold front had cleared all areas with the low approaching Caribou, ME.

By the 13th the storm was well gone and a northwest flow of well mixed (no more inversions) air was well established. Albany's 12z 850 mb temp was -11 and dropping.