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 , 4:41 PM GMT on August 31, 2014
Tropical wave 99L is spreading heavy rains over Belize and Mexico's Yucatan Peninsula as the storm heads west-northwest at about 10 mph. Belize radar shows little rotation to 99L's echoes, and satellite loops on Sunday morning showed the heavy thunderstorm activity was poorly organized, with few low-level spiral bands. Sea Surface Temperatures (SSTs) were very warm, near 29.5°C (85°F), and wind shear was moderate, 10 - 20 knots. These conditions are favorable for development, but 99L will not be able to develop until it finishes crossing Mexico's Yucatan Peninsula and emerges into the Gulf of Mexico's Bay of Campeche on Monday. The 8 am Sunday run of the SHIPS model predicted that conditions will remain favorable for development over Bay of Campeche during the remainder of the week, with mpderate wind shear, a moist atmosphere, and warm SSTs of 29.5°C (85°F.) None of our three reliable computer models for predicting tropical storm formation showed 99L developing in their Sunday morning runs, though. In their 8 am EDT Sunday Tropical Weather Outlook, NHC gave 99L 2-day and 5-day development odds of 30% and 50%, respectively. If a tropical storm does form in the Bay of Campeche, the most likely track would be to the west-northwest or northwest, with landfall occurring on the Mexican coast south of Texas on Wednesday. An Air Force hurricane hunter aircraft has been tasked to investigate 99L on Monday afternoon, if necessary.
Hurricane expert Steve Gregory has a more detailed look at the tropics in his latest blog post.
Figure 1. Latest satellite image of Invest 99L in the Western Caribbean.
Death Valley ‘Sliding Rocks’ Mystery Resolved
Scientists have long puzzled over how huge rocks on Death Valley's Racetrack Playa managed to slide over the dry lake bed, leaving tracks hundred of feet long. The mystery was solved last week, as detailed by wunderground's weather historian, Christopher C. Burt, in his latest blog post.
Figure 2. Mysterious tracks left by sliding rocks in the dry lakebed of Death Valley's Racetrack Playa as captured by wunderphotographer PugetSoundPost on March 25, 2013.
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