Rina pulls its punch; Thai floods worsen; Texas gets snow

Tropical Storm Rina is being ripped apart by strong upper-level southerly winds creating 30 knots of wind shear over the storm. Visible satellite loops show that the low-level circulation of Rina is just a naked swirl over Cancun, on the northeastern tip of the Yucatan Peninsula. The shear has torn away Rina's heavy thunderstorms so that they lie about 200 miles to the northeast of the center. Cancun radar shows almost no rain affecting the northeastern Yucatan Peninsula and surrounding the waters, even though the center of the storm is directly over Cancun. Last night, Rina brought wind gusts of up to 41 mph to Cancun and 43 mph at Cozumel, where 8.20" of rain fell yesterday. Damage from Rina to Cozumel and Cancun should be very minor, and I expect the hotels there will be open for business today.

Rina will continue to be sheared apart today, with the low level center expected to drift slowly southwards along the Yucatan coast. Long range radar out of Key West shows that moisture streaming to the northeast from Rina is bringing rain to the Southwest coast of Florida. Rainfall amounts of 1 - 3 inches are likely over the Florida Keys and South Florida through Sunday due to moisture from Rina. Wind shear should be able to destroy the circulation of Rina by Saturday.


Figure 1. What tropical storm? It's hard to tell a tropical storm with 45 mph winds was centered over this beach in Cancun, Mexico this morning. Rina's heavy rains and strong wind were several hundred miles to the northeast of Cancun this morning, thanks to strong upper-level winds that sheared the storm apart.


Figure 2. Morning satellite image of Tropical Storm Rina showing the center of circulation over the northeast tip of the Yucatan Peninsula, and the heavy thunderstorms several hundred miles to the northeast of the center.

Elsewhere in the Atlantic
A broad region of low pressure in the Western Caribbean between Jamaica and Honduras is drifting slowly northwest at less than 5 mph. Heavy thunderstorm activity is disorganized and relatively modest, and NHC is giving the region a 10% chance of developing into a tropical depression by Sunday. Heavy rains from the disturbance will affect Honduras, the Cayman Islands, and Nicaragua Friday through Sunday. None of the reliable computer models are showing development of a new tropical depression in the Atlantic over the next seven days, though we will continue to see disturbed weather over the Western Caribbean that could generate something.

Thailand's Great Flood likely to peak this weekend
The most damaging natural disaster in Thailand history is growing more serious, as the flood waters besieging the capital of Bangkok continue to overwhelm defenses and inundate the city. Heavy rains during September and October have led to extreme flooding that has killed 373 people and caused that nation's most expensive natural disaster in history, with a cost now estimated at $6 billion. Thailand's previous most expensive disaster was the $1.3 billion price tag of the November 27, 1993 flood, according to the Centre for Research on the Epidemiology of Disasters (CRED). Floodwaters have swamped fields and cities in a third of Thailand's provinces, affected 9 million people, and damaged approximately 10% of the nation's rice crop. Thailand is the world's largest exporter of rice, so the disaster may put further upward pressure on world food prices, which are already at the highest levels since the late 1970s. The highest tide of the month occurs this weekend at 8:07 am ICT in the capital of Bangkok, and the additional pressure that incoming salt water puts on the flood walls protecting the city is a major concern. Fortunately, the monsoon has been quiet this week over Southeast Asia, and the latest GFS model precipitation forecast show little additional rain over the country in the coming week. Heavy monsoon rains are common in Thailand and Southeast Asia during La Niña events, and we currently have a weak La Niña event occurring. Ocean temperatures in the waters surrounding Thailand during September and October have been approximately 0.3°C above average, which has increased rainfall amounts by putting more water vapor into the air. The remains of Tropical Storm Haitang and Typhoon Nesat also brought heavy rains in late September which contributed to the flooding.


Figure 3. Top ten most expensive natural disasters in Thailand since 1900, as tabulated by the Centre for Research on the Epidemiology of Disasters (CRED). This month's disaster (number one on the table above) is not yet in the CRED data base.

Texas gets its first snow of the season
The first snow of the season blanketed parts of the western and central Oklahoma and Texas Panhandles yesterday. Officially, Amarillo, TX picked up 3.1" of snow, which was a record for the date (old record: 2.4" on Oct. 27, 1911.) Areas 6 miles southwest of Amarillo got up to five inches of snow. Amarillo's heaviest October snow on record was 9.0" on Oct.21 - 22, 1906. The earliest measurable snowfall at Amarillo is 0.3" on Sept. 29, 1984. Yesterday's snow was quite a contrast from Tuesday's weather, when the high hit 86°F in Amarillo! Normally Texas would grumble about getting snow so early in the year, but yesterday's 1.23" of precipitation in Amarillo was over 25% of their precipitation for the entire year. Amarillo has now had 4.84" of precipitation this year, which is almost 14" below normal. Wunderground's weather historian Christopher C. Burt has the latest on the Texas drought in his latest post. He noted that Pecos, TX had received a paltry .48" so far this year, and that the driest calendar year in Texas records was 1.64" at Presidio in 1956. Well, Pecos got another 0.02" yesterday to bring their yearly total to 0.50", so that city is still on track to record the lowest rainfall of any city in Texas history.

My next post may not be until Sunday or Monday, depending upon the weather.

Jeff Masters