Tropical Weather Discussion...As expected Alex has obtained hurricane status, that's really no surprise. It appears tonight that Alex will not be throwing any surprise party by moving off course. Everything is right on track with the previous forecast laid out. Here are the latest specifics as of 10p.m.
Hurricane Alex Advisory...
Alex now the season's first hurricane...no real changes to the forecast track...landfall expected Wednesday night in the Rio Grande Valley in South Texas or Northeast Mexico...heavy rains expected across our area for the next couple of days...
10p.m. CDT Tuesday, June 29, 2010
Latitude: 23.1 N
Longitude: 94.8 W
This position is about 195 miles ESE of La Pesca, Mexico and 255 miles SE of Brownsville, Texas.
Winds: 75 mph w/ higher gusts. This makes Alex the season's first hurricane, and a category 1 hurricane on the Saffir-Simpson hurricane scale. Hurricane force winds extend outward to 15 miles from the center, and tropical storm force winds extend outward to 175 miles from the center. Additional strengthening is forecast tonight and Wednesday before Alex makes landfall Wednesday night. Alex will likely continue to slowly strengthening until landfall.
Movement: West or 280 degrees @ 9 mph. This nearly due Westward is believed to be temporary, and Alex should resume a more WNW to NW motion overnight. A general WNW direction is expected for the next 24-48 hours, and on this track Hurricane Alex will approach the Gulf coastline of South Texas and Northeast Mexico Wednesday, and make landfall Wednesday night in the hurricane warning area.
Minimum Central Pressure: 28.73" or 973 mb.
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. A 1-2' rise in tides is expected along the coastline of SE Texas and SW Louisiana. This will lead to minor coastal flooding with tidal backup occurring at the lower end of area rivers as well.
Tornadoes...Isolated tornadoes are expected across South Texas and Northeast Mexico close to the center of circulation on Wednesday and Thursday. An isolated tornado or two could occur in the outermost rain bands which will rotate through the forecast area over the next couple of days, but the tornado threat here seems minimal at this time.
Discussion...Recon data is trickling in tonight, and as expected Alex is indeed the season's first hurricane. Alex is showing signs of continued organization and strengthening tonight, and since the storm is in a low-shear environment and there is nothing to act as an impediment over the Gulf, Alex is forecast to continue strengthening through the night and through the day on Wednesday. It is possible that Alex will reach category 2 status before making landfall on either side of the Rio Grande Valley Wednesday night. The current forecast doesn't depict that Alex will reach category 2 status, however it does reflect a strong category 1 with winds 90-95 mph. Landfall is about 24 hours away, give or take a few hours depending on how Alex moves at the coast. The models are all clustered over the Rio Grande region, and there is absolutely no reason to deviate from the forecast laid out by the NHC. They have done a great job forecasting this storm. Alex is being steered around the periphery of an anti-cyclone that is currently in place over the Central United States. Alex has wobbled Westward over the past few hours, but the resumption of a general WNW track is expected later tonight and Wednesday. The forward speed may also slow just a little bit, but Alex should continue to be steered by the anti-cyclone in the nation's mid-section. Alex is a large tropical cyclone, and his effects will be felt over a large area.
It is so important to not just focus on the center line that is the forecast track. The rainbands from Alex are already moving onshore in the strike zone, and this will continue through the night and conditions will progressively worsen in these areas on Wednesday. Across our area, the outer rainbands from Alex will influence the weather over the next couple of days. Other than periods of heavy rain and squalls, and an increase in tides along the coast the effects of Alex will be minimal in SW Louisiana and SE Texas. Rainfall amounts of 2-4" area wide are expected through Friday with isolated higher amounts over 6" possible especially near the coast. A long fetch onshore flow will develop as well on the NE side of the circulation. Winds will be gusty in 20-30 mph range at times especially in squalls. The expected heavy rain could lead to some localized flooding, and as a result the National Weather Service in Lake Charles has issued a Flash Flood Watch in effect through Thursday morning for the parishes and counties along and South of the I-10 corridor. A Coastal Flood Watch also remains in effect through Thursday for the anticipation of coastal flooding due to the strong onshore flow. While far removed from the main circulation of Alex, an isolated tornado or two can't be ruled out across the forecast area especially in the strongest squalls and rainbands near the coast. The threat for heavy rain will gradually taper off by the weekend as Alex spins down over the mountains of Mexico.
The question still remains how the path of Alex will affect the oil spill. It is likely that the strong South wind will drive more oil towards the Louisiana coast, and with a SE wind across our area some of the oil could move closer to our area. However, it is not clear if any of the oil will reach SW Louisiana at this time. The cleanup and repair operations will have to be ceased because of the strong winds and seas. The strong waves and seas over the Gulf will stir up the oil slick, and disperse it over a wider portion of the Gulf. The oil will not simply just dissolve or disburse. There is still a lot of uncertainty as to what exactly will happen.
That's all for this update. The National Hurricane Center issue an intermediate advisory at 1a.m. CDT Wednesday, followed by the next complete advisory at 4a.m. My next update on Alex will be Wednesday morning. I will have a regular forecast discussion posted in an hour or two.
Have a great Tuesday night and God bless!
-DM-
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