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Dangerous Jova approaching Mexico; welcome rains hit Texas

By: Dr. Jeff Masters, 1:54 PM GMT on October 10, 2011

In the Eastern Pacific off the coast of Mexico, Hurricane Jova continues to intensify. Recent satellite loops show the hurricane has developed a prominent eye with very cold cloud tops. A hurricane hunter aircraft is scheduled to arrive at Jova near 11 am PDT today. The computer models are in good agreement that Jova will turn northeast and then north on Tuesday, with storm expected to hit near Manzanillo on Mexico's southwest coast Tuesday afternoon. The intensity forecast also appears relatively straightforward. Jova is under moderate wind shear of 10 - 15 knots, and shear is predicted to stay in the moderate range between now and landfall. Ocean temperatures are warm, 28 - 29°C, and Jova is now approaching a region where these warm waters extend to great depth, which should allow the storm to maintain major hurricane strength until landfall. The GFDL model predicts Jova will be a Category 3 at landfall on Tuesday afternoon, while the HWRF model predicts Category 4 strength. The hurricane is likely to undergo the usual fluctuations in intensity due to eyewall replacement cycles major hurricanes typically experience at this stage of their lifetimes, so Mexico will have to hope it catches Jova on one of the downswings of this cycle. If Jova maintains its current central pressure of 960 mb until landfall, it will rank as one of the ten most intense Pacific hurricanes to hit Mexico since record keeping began in 1949. According to a comprehensive list of Eastern Pacific hurricane landfalls at Wikipedia, only seven hurricanes with a central pressure of 960 mb or lower have hit Mexico's Pacific coast since 1949. Jova is a modest-sized hurricane, with hurricane-force winds that extend out only 15 miles from the center. A relatively small stretch of moderately to lightly-populated coast will see Jova's high eyewall winds and very dangerous storm surge. A much larger swath of Mexico will see very heavy rains of 5 - 10 inches, and these rains are capable of causing high loss of life due to heavy flooding and mudslides.

Figure 1. Rainfall forecast for Hurricane Jova from this morning's 2 am EDT run of the GFDL model. Image credit: Morris Bender, NOAA/GFDL.

Tropical Storm Irwin also headed for Mexico
Once Jova has made landfall, Tropical Storm Irwin, farther to the west, may also be a concern. The computer forecast models show Irwin could make landfall as a tropical storm on the Mexican coast late in the week, along the same stretch of coast Jova will affect. However, Irwin is a weak storm that is expected to weaken further as it approaches the coast, due to high wind shear, and Irwin may end up not being a significant threat to Mexico.

93L bringing heavy rains, high winds, and a tornado threat to the Southeast U.S.
A large extratropical low pressure system with heavy rain and gale-force winds (Invest 93L), is centered over Northern Florida. Water vapor satellite loops show that the center of this low is filled with dry air, and 93L is headed northwest at 5 - 10 mph. The west side of this low also has a large amount of dry air, which is limiting precipitation amounts along the Gulf of Mexico coast, but the east side has plenty of tropical moisture. Radar-estimated rainfall amounts since Friday are already in excess of ten inches just inland along the Central Florida coast. Melbourne, Florida had its second wettest October day in its history on Saturday, with 5.68" of rain. Much of coast of Northern Florida, Southern South Carolina, and Georgia, including Brunswick, are under a flood watch, high surf advisories, tornado watch, and a high wind watch for wind gusts up to 55 mph. Winds offshore the Southeast Coast are not quite as strong as last night, when tropical storm force winds occurred along the Central Florida coast. Buoy 41009 offshore from Cape Canaveral recorded sustained winds of 52 mph, gusting to 67 mph, at 10 pm EDT Sunday. St. Augustine airport had sustained winds of 38 mph with gusts as high as 51 mph Sunday night. Due to the large amount of dry air near the storm's center and west side, plus the fact the track of the storm will spend little time over water, 93L will not have time to organize into a subtropical storm that gets a name. NHC is currently giving 93L a 10% chance of becoming a named tropical or subtropical storm by Wednesday morning. This large diffuse system will bring strong winds and heavy rains to a large area of the Southeast U.S. coast over the next two days.

Elsewhere in the Atlantic, both the ECMWF and NOGAPS models predict a strong tropical disturbance could form in the Western Caribbean off the coast of Nicaragua in about seven days.

Figure 2. Radar-estimated rainfall from the Tampa Bay, Florida radar as of Monday morning.

Heavy rains for drought-stricken Texas
A slow-moving low pressure system brought the heaviest rains of the year to large portions of rain-starved Texas, Oklahoma, and Kansas over the weekend. Radar-estimated rainfall amounts reached eight inches over portions of Texas between Dallas and Abilene. Houston got 20% of their rain for the entire year--3.02"--on Sunday, breaking a string of 256 consecutive days the city had gone without a one-inch rainstorm. The longest previous such streak was 192 days, set in 1917 - 1918. The last one inch rainstorm in the city was January 24, 2011. The last time Houston had a two inch rainstorm was 383 days ago. Yesterday's rains brought the year-to-date precipitation to 15.25", which is 22" below normal.

Figure 3. Radar-estimated rainfall from the Dallas, Texas radar as of Monday morning.

Jeff Masters
Vero Beach, FL
Vero Beach, FL
Flooding in neighborhoods from 10+ inches of rain in the last 3 days. Photo by R.J.LeBleu
Streets turn into temporary creeks.
Streets turn into temporary creeks.
Luckily I was on the shallow side of this divided roadway as I slowly inched along to avoid stalling. On the Space Coast barrier island the waters generally flow west back into the Banana River Lagoon.
a reprieve from drought. Bosque River
a reprieve from drought. Bosque River
Erath County, City Park at Stephenville.


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