Bombogenesis and the Valentine's Day 2007 Storm

Feb  13, 2007 - The Valentine's Day Storm this year will bring damaging winds (hurricane force) to the coastal areas and the Cape and Islands due to a  "bombogenesis" or rapid intensification of a storm.

"Bombs" often result in Nor'easters, as is the case tomorrow. A heavy accumulation of snow as well as sleet, freezing rain, and at times possibly rain make this a complex dangerous storm.

This storm is similar to what I recall Thanksgiving 72's being, where the heaviest snows migrated to Albany and they got 24". I'd expect they will get that again. Springfield is more or less on the border of the big amounts, but tends to 'downslope' on a brisk east wind aloft. Albany will probably be more prone to a northerly wind, so they may keep the totals high. Watch for a 'surprise' in the middle of this one tomorrow.. more on that in future updates!

"Bombogenesis" is a term which some folks scoff at, but is an actual meteorological slang word adopted by most eastern seaboard meteorologists for a strengthening coastal storm, similar to a quickly deepening hurricane. Some have even adopted the new term "Wintercane", but this is just a re-hash of an older term I believe, "Neutercane"  which was popular after the Blizzard of 1978.

Bombogenesis is the extreme intensification of a cyclone or low-pressure storm system characterised by a drop in surface pressure of at least 24 millibars in 24 hours.

Intense winds arise as the height contours build around the center of rotation with the number of height contours increasing rapidly in the developing stages of the "bomb".

This rapid intensification typically occurs between a cold continental air mass (see associated post on Continental Air Masses coming later today)  and warm ocean waters or between a cold polar air mass and a much warmer air mass.

Read more about bombogenesis at Jeff Haby's HabysHints. Learn more about Low Pressure systems At the University of Illinois WW2010 page "Low Pressure Centers".

Read more about storms at NASA's Clouds Generated During Midlatitude Storms

"Categorizing storms according to their sea level pressure patterns is   another way of classifying storms. By plotting central sea level pressure against time a pressure profile can be created. All storms do not conform to the same sea level pressure pattern throughout its life. Some storms can be classified as classical storms. These are storms where their pressure profiles are "V" shaped or have a dip pattern in pressure. Oscillating storms are those with insignificant pressure changes, while ascending storms increase in pressure over time. Descending storms are those that decrease over time in pressure only."

Also possibly of interest given the anomalous season thus far:
Northern Hemisphere Winter Surface Temperature Predictions based on Land-Atmosphere Fall Anomalies

For information on how to read weather charts, computer models, etc, on the internet, I recommend Peter Chaston's book Weather Maps, 3rd Edition, which you can order by clicking here or by emailing me .