Tropical Weather Discussion...Alex continues his Southern Gulf journey on this Tuesday afternoon. He is slowly strengthening this afternoon, and seems poised to reach hurricane status tonight. It's time to give you all the latest specifics on Alex.
Tropical Storm Alex Advisory
Alex slowly strengthening...likely to become season's first hurricane tonight...forecast right on track...
4p.m. CDT Tuesday, June 29, 2010
Latitude: 23.2 N
Longitude: 94.0 W
This places the center of circulation of Alex about 245 miles E of La Pesca, Mexico and 290 miles SE of Brownsville, Texas.
Winds: 70 mph with higher gusts. Satellite imagery indicates that Alex is becoming better organized, and a Hurricane Hunter Aircraft will investigate the system shortly. Alex will likely be upgraded to a category 1 hurricane this evening. Continued strengthening is expected until landfall Wednesday night. Tropical Storm force winds now extend outward to 175 miles from the center of circulation.
Movement: NW or 310 degrees @ 13 mph. This motion should continue tonight, before a gradual turn to the WNW and W occurs Wednesday and Wednesday night. Some reduction in forward speed is also expected on Wednesday. On the forecast track, Alex will be approaching the Gulf Coast of Northeastern Mexico and Southern Texas on Wednesday. Landfall will occur Wednesday night in the hurricane warning area.
Pressure: 28.97" or 981 mb.
Watches/Warnings...There is no change to the Hurricane Warning which was issued Monday night. It remains in effect from Baffin Bay, Texas to La Cruz, Mexico. The Tropical Storm Warning remains in effect from Baffin Bay, Texas to Port O'Connor, Texas. As of the 4p.m. advisory, the government of Mexico has issued a Tropical Storm Warning from La Cruz to Cabo Rojo.
A hurricane warning means that hurricane conditions are expected somewhere in the watch area. A warning is typically issued 36 hours before the first occurrence of tropical storm force winds are expected to occur. These are the conditions that make outdoor preparations dangerous and difficult.
A tropical storm warning means that tropical storm conditions are expected somewhere in the warning area within 36 hours. Tropical storm conditions are expected to reach the coastline in the hurricane warning area by Wednesday morning. These winds will make outdoor preparations dangerous, and persons in the warning area need to complete protection of life and property by this time.
Rainfall...Alex should produce 6-12" of rain across the Lower Rio Grande Valley of NE Mexico and S Texas. Isolated amounts of 20" are possible in these locations. These rains will likely cause life-threatening flash floods and mudslides. Rainbands from Alex are already spreading onshore in the strike region. Alex is a large tropical cyclone, and his rainbands are far reaching. The rainbands extend along the Northern Gulf coast from Florida to Texas, and in these areas far away from the brunt of the storm, rainfall totals will generally be 2-4" with isolated amounts in excess of 6". Some flash flooding will be possible through Friday.
Storm Surge...Storm surge values of 3-5' are expected near and to the North of the center. The storm surge will be accompanied by large and destructive waves along the coast.
Discussion...We are getting within the 24 hour window before landfall on this Tuesday evening. Alex is behaving quite nicely as far as the expected forecast track. It has been reluctant to develop further today, but it is getting more organized at this time. It will likely be a hurricane on the next advisory as an Air Force Hurricane Hunter Aircraft is en route to investigate the system. Alex is being steered around a strong anti-cyclone over the Great Plains and Mid West. The environment over the Gulf continues to be very supportive for additional development, and there is no reason why Alex won't continue to strengthen through Wednesday. Alex is forecast to be a category 1 at landfall, but if it can strengthen at a more rapid pace before landfall category 2 status isn't out of the question. Landfall should occur Wednesday night or early Thursday if the storm slows down a bit more than expected. Landfall will be right in line with the official forecast track, but wobbles one way or the other will determine which side of the Rio Grande Alex will make landfall on. I will stick with the idea of a landfall on the U.S. side of the Rio Grande, although the official track suggests a landfall just across the Rio Grande in NE Mexico. All model guidance is clustered in this region, and the models are generally very close to where landfall will ultimately occur within 24 hours or so, so again there is no reason to deviate from previous forecasts.
Forecast confidence is high concerning where landfall will be, and no matter which side of the Rio Grande Alex makes his landfall, the effects on SW Louisiana will be the same. Rainfall will be the main weather story around our part of the world. 2-5" of rainfall is expected through Thursday for most areas, with isolated amounts in excess of 6" possible. A Flash Flood Watch has been issued through Thursday morning by the National Weather Service in anticipation of some heavy rainfall associated with Alex. This flood watch is for parishes and counties along and south of I-10. Minor coastal flooding is also possible along the coast, but it should not be a major issue. Winds will pick up a bit, and a long fetch of SE winds is expected. Winds will be on the order of 20-25 mph at times especially in squalls, but other than that no major issues across the forecast area, mostly just some tropical rains.
That's all for this update. The next intermediate advisory by the National Hurricane Center will be issued at 7p.m. followed by the next complete advisory at 10p.m. My next Alex update will follow the 10p.m. update from the National Hurricane Center. Also, look for the detailed regular forecast discussion later tonight as well. It will detail the effects from Alex across our area.
Have a good evening & God bless!
-DM-
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