Tropical Weather Discussion...Good afternoon. On this last Monday of June, Alex continues to be the big weather story, and continues his strengthening trend over the Gulf. New watches and warnings have been issued. Here are the specifics.
Tropical Storm Alex
1p.m. CDT Monday, June 28, 2010
...Alex Strengthens...Could Become Season's First Hurricane Tonight...
Latitude: 20.3 N
Longitude: 91.7 W
This places the center of circulation about 85 miles WNW of Campeche, Mexico and 535 miles SE of Brownsville, Texas.
Winds: 60 mph...Alex has been strengthening and will continue do so. Alex should approach hurricane strength this afternoon, and will likely reach hurricane status tonight or early Tuesday. Tropical storm force winds currently extend outward to 70 miles from the center.
Movement: NNW or 330 degrees at 5 mph. This general motion is forecast to continue through Tuesday. After this point, a turn back to the NW is expected, but this remains to be seen. It all hinges on the development of a ridge across the Central U.S.
Minimum Central Pressure: 29.23" or 990 mb.
Watches/Warnings...As of 10a.m. a Hurricane Watch has been issued for a portion of the Western Gulf of Mexico coastline. The Hurricane Watch is in effect along the coasts of Mexico and Texas from La Cruz, Mexico to the Mouth of the Rio Grande River on the U.S./Mexico border, and from the Rio Grande River to Baffin Bay, Texas. A Hurricane Watch means that hurricane conditions are possible in the watch area. A watch is typically issued 48 hours before the onslaught of tropical storm conditions are expected, as these conditions will make outside preparations difficult or dangerous.
Rainfall...Additional rainfall totals of 3-6" are expected across the Yucatan Peninsula, Guatemala, and Southern Mexico through Tuesday. Isolated amounts of 10" or more are possible in mountainous areas. The heavy rains from Alex should reach Northern Mexico and Southern Texas by Wednesday. Alex is a large tropical storm, and the outer rain bands will rotate Northward towards the Northern Gulf coast, and affect Louisiana, Mississippi, Alabama, and the Florida Panhandle throughout the week. 2-4" of rain is possible across our area.
Discussion...Alex continues to strengthen as expected early this afternoon. The environment over the Southern Gulf is one that is very conducive to further development, and the intensity forecast reflects this. The official forecast has been shifted to the right (NE) of the previous forecast package. The entire model suite has shifted right, and the official forecast track is on the left side of the average of all models at this time. The official track takes Alex inland Thursday morning just South of the Rio Grande River on the U.S./Mexico border. The intensity forecast has also been revised upward, and Alex is expected to make landfall Thursday as a strong category 2 hurricane with 110 mph winds. It is not out of the realm of possibility that Alex could obtain major hurricane status before making landfall. The longer time Alex spends over the Gulf, the longer it will have time to intensify. Alex's forward progression has slowed considerably during the last 24 hours. A very slow NNW progression is expected for the remainder of today, before it accelerates somewhat on Tuesday. It has been moving around the SW periphery of a ridge of high pressure anchored over the SE U.S., but this high is weakening, and steering currents are collapsing over the Western and Southern Gulf. We turn our attention to some synoptic scale features downstream that will ultimately steer Alex.
The same features discussed in previous discussions are still valid. An approaching trough is advancing towards the Gulf coast, and it remains to be seen how much of an influence this will have on Alex. The weakness that was expected to develop along the Gulf coast has indeed done so. It is responsible for the more Northward motion over the last 24 hours, and this will continue to be in place for at least another 24-36 hours. A secondary ridge is shown by forecast models to develop to the North of the advancing trough beyond 36 hours. This ridge over the Central U.S. could be strong enough to steer Alex back to the W or WNW into Northern Mexico or South Texas on Thursday. However, if the ridge isn't as strong as models depict and the trough is stronger than anticipated, then Alex will not show much Westward motion, and the current NNW to North motion will continue, thus bringing landfall at a point further up the Texas coast. This would also increase the threat for SW Louisiana at the end of the week. There is still some model inconsistencies that exist, and nothing is cut and dry yet. Although, the latest model suite is clustered from near Corpus Christi to just South of the U.S./Mexico border. The current official track is a consensus (average) of this morning's forecast models. I am staying the course, and I believe landfall will be in the U.S. on the Texas coast between Brownsville and Corpus Christi Thursday. Alex will certainly be a formidable hurricane at landfall as well. Based on the environment Alex is currently in, I believe reaching major hurricane of category 3 strength is not out of the question. If the trough is stronger and Alex approaches a point further North closer to SW Louisiana, landfall would occur later most likely Friday, and that will also increase the odds of a stronger storm as well. Although, if the trough picks up Alex, the environment over the Northern Gulf waters will be as favorable for continued strengthening as the Southern Gulf is. The advancing trough would produce wind shear from the SW over the Northern Gulf, and this shear would in turn act to weaken Alex as it approaches the coast. The jury is still out on this. All Gulf coast residents from Tampico, Mexico to New Orleans need to keep a watchful eye. Louisiana is by no means out of the woods yet.
Assuming Alex takes the projected path laid out by the NHC, the question is what kind of effects would SW Louisiana experience and what effect will this track of the storm have on the oil spill zone? First, there will certainly be impacts on our part of the world. An increase in moisture is a given with a stiff onshore flow. The chances for showers and thunderstorms and occasional squalls around the outer periphery of Alex are expected this week. Activity will be scattered today, but should be more numerous beginning Tuesday, and rain chances shoot up into the likely category from Wednesday-Friday at least. Rain could be in the likely category for the 4th of July weekend as well. More on that later. Rainfall will be heavy at times and 2-4" is expected on average this week, with some locations receiving over 6" across South Louisiana. The circulation around Alex will also lead to tidal backup along the coast, and a rise in tides. Coastal flooding issues are anticipated as Alex moves towards the coast. The National Weather Service has issued a Coastal Flood Watch in anticipation of this possibility through Thursday. Strong E to SE winds will lead to the tidal backup. Winds near tropical storm force in our coastal waters can't be ruled out, but on the current track tropical storm conditions are not expected inland. Winds will be gusty at times with gusts over 30 mph at times by Wednesday and Thursday. The further West you go, the higher the winds will be. It is possible that tropical storm conditions will be experienced in the Houston area on the current track. Of course, a more Northward track would worsen the expected conditions across SW Louisiana. Winds and seas in the offshore waters will likely hamper clean up efforts in the oil spill zone. Operations will likely have to be ceased in the next day or two. It is unclear at this time if the current prognostication for landfall will lead to oil approaching the coastline here in SW Louisiana. Once again, a track further to the right will increase the possibility of such an occurrence. Everyone needs to keep a watchful eye, and just have your plan in place should things change. Just keep checking back here for all the latest, and do some praying.
That's all for this update. The next complete advisory by the National Hurricane Center will be issued at 4p.m. CDT, and my next update will follow that once I collect data and look at the latest models. I will also have a regular forecast discussion for you, so you'll know exactly what kind of weather we can expect this week. Look for that tonight. Remember, there's no need to turn anywhere for the most complete and accurate weather information that you expect and can count on, than right here on this blog.
Have a good Monday afternoon! God bless!
-DM-
Thanks for the great detailed information Drew!!!
ReplyDeleteShantele