Dr. Masters co-founded wunderground in 1995. He flew with the NOAA Hurricane Hunters from 1986-1990. Co-blogging with him: Bob Henson, @bhensonweather
By: Dr. Jeff Masters , 3:01 PM GMT on November 10, 2009
A weakening Tropical Storm Ida limped ashore near Dauphin Island, Alabama at 5:40 am CST this morning, as a tropical storm with 45 mph winds. Winds at coastal locations during Ida's landfall were mostly below tropical storm force. One exception was Dauphin Island, where winds peaked at 40 mph, gusting to 50 mph, near midnight. Radar-estimated rainfall from Ida showed many regions received 3 - 5 inches of rain (Figure 1), which has caused some minor river and street flooding. The main damage from Ida seems to have been beach erosion, as a 3 - 6 foot storm surge topped by battering waves affected a long stretch of coast, from Southeast Louisiana to the Florida Panhandle. Ida drove a 5.5 foot storm surge to Shell Beach, LA (on the east side of New Orleans). Ida did not spawn any tornadoes, and the Storm Prediction Center Discussion for today maintains that the airmass in place over the Gulf Coast is relatively stable, and the prospects for severe weather today are low.
Ida's remnants and Invest 98L
Ida is expected to transition to a strong extratropical storm later today, then move off the U.S. Southeast coast by Thursday. Minor to moderate coastal flooding is possible along the Atlantic coast from Georgia to North Carolina beginning Thursday, as the counter-clockwise flow of air around Ida's extratropical version brings winds of 25 - 35 mph to the coast.
Joining the fun on Thursday may be another extratropical storm (Invest 98L), currently spinning over the Atlantic a few hundred miles north of Puerto Rico. This disturbance is under 30 - 40 knots of wind shear, and will not be able to develop today. However, wind shear will fall to the moderate range, 10 - 20 knots, Wednesday through Thursday, and the storm may begin to acquire some subtropical traits as it moves northwest towards the Southeast U.S. coast. There won't be enough time for 98L to develop into a subtropical storm, since by Thursday night it will be interacting with the remains of Ida, which will bring prohibitively high wind shear over 98L.
Figure 1. Estimated precipitation for Ida, from the Mobile, Alabama radar.
Figure 2. Observed vs. predicted water levels at Shell Beach, LA (just east of New Orleans). The green line shows how high above normal the water is. For Shell Beach, it peaked at 5.5 feet above normal between 8 - 10 pm EST last night, and is now falling. Image credit: NOAA Tides and Currents.
El Salvador floods kill at least 130
Heavy rains that began on Thursday due to tropical disturbance 96E have killed at least 130 people in El Salvador, with 60 people still missing. The flooding hit the capital of San Salvador and rural areas to the east. The heavy rains were due to tropical disturbance 96E, which formed off the coast of El Salvador on Wednesday, November 4. The counter-clockwise flow of air around the disturbance pulled large quantities of moist, Pacific air over the coastal mountains in El Salvador, dumping steady rains of up two inches over central El Salvador, Thursday through Friday. On Saturday evening, November 7, an extremely intense thunderstorm complex developed over central El Salvador, dumping up to 17.4" (442 mm) of rain on the slopes of the Chichontepec volcano just east of the capital of San Salvador. Huge mudslides rumbled down the mountain, burying the the town of Verapaz, some 30 miles (48 km) east of San Salvador.
Figure 3. Collapsed bridge at Santa Cruz La Libertad, El Salvador. Image credit: Wunderphotographer DiegoSagrera
This weekend's flooding disaster was the second deadliest weather disaster in El Salvador history. The deadliest was from Category 5 Hurricane Mitch, which killed 240 people in 1998. Ranking third is Category 1 Hurricane Stan of 2005, which brought heavy rains that killed at least 72 people. El Salvador is very vulnerable to flash flooding, since the nation is the second most deforested country in the Americas, next to Haiti. Approximately 85% - 90% of the nation's forests have been destroyed since the 1960s, and the rate of destruction--now 1.7% per year--has accelerated since 2000. Most deforestation in El Salvador results from the country's high population that relies heavily on the collection of fuel wood and subsistence hunting and agriculture. Although the government has protected areas of forest, forestry laws go unenforced due to lack of funds and management. Salvanatura.org, the Ecological Foundation of El Salvador, is working on efforts to help protect the forests of El Salvador from continued destruction. Expect to hear of more frequent flooding disasters in El Salvador in the coming decades, as the country loses more of its forests, and as global warming brings an increase in heavy precipitation events due to higher amounts of water vapor in the atmosphere.
Figure 4. Rainfall for the period 7 am Saturday, November 7, through 7 am Sunday, November 8, over El Salvador. Rainfall amounts in excess of 300 mm (about 12 inches, black colors) occurred over central El Salvador, near the capital of San Salvador. Image credit: El Salvador Weather Service (SNET).
For those interested in making a donation to assist in disaster relief for El Salvador, Portlight.org has a Paypal donation page set up for this. All funds raised will be forwarded to José Luis Escobar Alas, Catholic Archbishop of San Salvador, and used to assist flooding victims at the discretion of the Archbishop.
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