Dangerous Category 1 Lehar Headed for India; Wet Winter Storm for U.S. East Coast

Dangerous Category 1 Cyclone Lehar is intensifying as it heads west-northwest at 8 mph towards India's Bay of Bengal coast. Satellite images show that Lehar--which is the Hindustani word for "wave"--has developed a large Central Dense Overcast (CDO) of high cirrus clouds over its center, which is characteristic of intensifying tropical cyclones approaching hurricane strength. With wind shear a moderate 10 - 20 knots and ocean temperatures a very warm 28 - 29°C, Lehar is expected to continue to intensify to a major Category 3 storm until just before landfall, which is expected to occur near 03 UTC Thursday, November 28 in the Andhra Pradesh state of India. This is the same portion of the coast that Cyclone Helen hit on Friday as a tropical storm with 40 mph winds. Helen's heavy rains killed eleven people, caused widespread severe agricultural damage, and left the soils saturated, which will make the rains from Lehar doubly dangerous. Also of concern is the storm surge, which will impact a portion of the coast that is heavily populated and low-lying. The India Meteorological Agency (IMD) is predicting that Lehar will generate a storm surge of up to 1.6 - 2.9 meters (5.2 - 9.5 feet) to the right of where the eye makes landfall.


Figure 1. Cyclone Lehar over the Andaman Islands in the Bay of Bengal at 04:25 UTC November 25, 2013. At the time, Lehar was at Category 1 strength with top winds of 75 mph. Image credit: NASA.

An unusually active tropical cyclone season for India
In addition to Cyclone Helen, India's Bay of Bengal coast also was hit this year by Tropical Cyclone Phailin, a Category 4 storm with 140 mph winds, which killed 44 people and did $1.1 billion in damage on October 12, 2013. It's unusual for India to get hit by so many named storms in one year; the last time three or more named storms did so was in 1996, when six storms of at least tropical storm intensity hit. Only four Bay of Bengal tropical cyclones have hit India at hurricane strength since 2000, if we include Cyclone Phailin from 2013. The others were:

Category 1 Cyclone Aila of May 25, 2009, which hit near Kolkata, killing 96, causing $553 million in damage.
Category 1 Cyclone Thane, of December 30, 2011, which hit Southeast India, killing 48, causing $376 million in damage.
Category 1 Cyclone 05B, which hit Southern India on November 29, 2000, killing six.

The last major tropical cyclone to hit the portion of the coast that Lehar is threatening occurred on June 14 1996, when Category 4 Tropical Cyclone 07B struck, killing 731 people. Wunderground's weather historian Christopher C. Burt has a detailed post on India's tropical cyclone history. During the past two centuries, 42 percent of Earth's tropical cyclone-associated deaths have occurred in Bangladesh, and 27 percent have occurred in India (Nicholls, R.J.N., N. Mimura, J.C. Topping, 1995, "Climate change in south and south-east Asia: some implications for coastal areas," J Glob Environ Eng 1995;1:137–54.)


Figure 2. Predicted precipitation for the 7-day period ending Monday, December 2, 2013. This week's storm is expected to dump heavy rains of 2+ inches along a long swath of the U.S., from Louisiana to Maine. Image credit: NOAA.

Winter Storm Boreas a heavy rain event for the coast
A powerful and very wet winter storm will slog across the Southeast U.S. Monday and Tuesday and up the Mid-Atlantic coast on Wednesday. The models have come into fair agreement that the storm, dubbed "Boreas", will be a heavy rain event for coastal New England and the Mid-Atlantic, with snow falling inland at higher elevations. The greatest snows of 6+ inches will likely fall on Tuesday through Wednesday in Southwest New York and Northwest Pennsylvania. Pittsburgh and Buffalo are under Winter Storm Watches, and could see 3 - 5" of snow, snarling travel on the busiest travel day of the year.

Jeff Masters