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 , 2:03 PM GMT on July 13, 2011
A tropical disturbance (Invest 97L) in the southernmost Gulf of Mexico in the Bay of Campeche has spun up very quickly into an impressive system with very heavy thunderstorm activity. Radar out of Alvarado, Mexico is showing some rotation to 97L, and the system is close to tropical depression strength. In a special statement issued at 9:15am EDT, NHC gave 97L a 50% chance of development before the storm moves ashore over Mexico this afternoon. The topography of the Bay of Campeche features mountains that help accelerate the counter-clockwise flow of low-level winds, making the region prone to sudden spin-ups of tropical storms.
Figure 1. Morning satellite image of Invest 97L.
97L a heavy rainfall threat
It is already raining in Veracruz, just to the south of where the center of 97L is expected to make landfall. Heavy rains of 3 - 6 inches can be expected over Mexico today and Thursday along 97L's track. These rains may cause flooding problems, particularly since the region impacted has been under extreme drought this year. The drought has killed much of the vegetation that ordinarily would slow down run-off. In late June, Tropical Storm Arlene brought flooding rains in excess of ten inches (250mm) to the coast just north of where 97L is expected to make landfall. These floods killed 22 people.
Figure 2. On June 30, 2011, Tropical Storm Arlene made landfall near Cabo Rojo in Veracruz, Mexico. The impact of Arlene’s heavy rain was clear in early July as the Moderate Resolution Imaging Spectroradiometer (MODIS) on NASA’s Aqua satellite passed overhead. MODIS captured the top image on July 5, 2011. For comparison, the bottom image shows the same area on June 19, 2011. The images use a combination of visible and infrared light to increase contrast between water and land. Water varies from electric blue to navy. Depending on land cover, areas above water range in color from green to brown. Clouds are pale to medium blue-green. A network of lakes extends inland from the city of Tampico. In the image from July 5, the lake network appears to have multiplied, with standing water covering large areas northwest and southwest of the city. Standing water is also apparent south of Cabo Rojo. Image credit: NASA.
The latest runs of the reliable models do not predict any tropical cyclone development over the next seven days,
I'll have a new post late this afternoon or early Thursday morning.
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