...Tropical Weather Discussion...
I hope everyone is having a great Labor Day weekend! I am cutting mine a bit short to tell you of our newest tropical entity. Tropical Storm Hermine formed in the SW Gulf of Mexico this morning, after a persistent area of low pressure over the weekend closed off into a tropical depression last night. Hermine formed from an old tropical depression in the Eastern Pacific, and it conglomerated with the old frontal boundary which came through late last week. Hermine will not be a major or direct threat across SW Louisiana, but it will be close enough to enhance our rain chances for the first half of the week. The direct impacts will be felt further South of our area into South Texas and North Mexico in the vicinity of the Rio Grande Valley. I will keep you updated through the day on all the latest on Hermine, and the typical format this blog follows for a tropical system is in effect now until further notice. A regular forecast discussion will also be posted tonight. For the most up to date information on Hermine, see the following text.
Tropical Storm Hermine Discussion...The season's eighth named storm has formed in a typical hotbed for tropical development this time of year. Hermine was upgraded from T.D. 10 earlier this morning while churning over the SW Gulf of Mexico. Hermine is in a very favorable environment, as judging by the quick intensification from an open wave on Sunday afternoon, to a Tropical Depression Sunday night, to Tropical Storm status this morning. There is no reason to believe that Hermine won't continue to strengthen until landfall on Tuesday morning. Hermine is in a low-shear environment and an area of very supportive SSTs. There is not much room for Hermine to continue to strengthen. It is close proximity to land. The forecast for Hermine is pretty straightforward as well. The cyclone is being steered around the Western flank of a strong ridge of high pressure which built in behind the recent cold front. This frontal boundary has basically lifted Northward, and dissolved along the Gulf coast. Hermine is moving between N and NW around the periphery of the aforementioned anti-cyclone. This will keep Hermine's direct impact safely away from SW Louisiana. Landfall will occur within the next 24 hours somewhere along the Western Gulf of Mexico coast. Slight wavering in the motion will dictate if Hermine makes landfall in Mexico or in Deep South Texas. The Rio Grande Valley seems to be the bullseye for the direct impacts of Hermine. Tropical Storm Warnings and Hurricane Watches are in effect for portions of Mexico and Texas.
Given the very supportive environs for Hermine, steady state strengthening is anticipated until landfall Tuesday. The current winds of 50 mph could certainly be stronger than that based on satellite representation, and we will know more this afternoon once a Hurricane Hunter Aircraft arrives on the scene. It is not out of the realm of possibility that Hermine could ramp up to a minimal hurricane before it makes landfall in the RVG Tuesday. However, no deviation of the forecast track is anticipated given the strength of the high that resides over the Gulf Coastal Plain. There will be impacts across SW Louisiana, but again the direct impacts will not be experienced around here. Impacts to SW Louisiana will come in the form of plenty of low-level moisture and humidity. The orientation of the actual center of circulation will place SW Louisiana on the moist, NE quadrant, therefore rain chances will shoot up into the likely category for today and tomorrow and likely stretch into Wednesday as the storm spins down over Central Texas. This will keep a deep, plume of tropical moisture surging Northward out of the Gulf. Rain will be heavy at times, and the possibility of several inches of rain will exist through Wednesday across the threshold of the forecast area. However, rain chances will be a bit less the further East you go, and higher in SE Texas. Given the drought conditions across the area, this rainfall will be beneficial to the region. No flooding problems are expected. Coastal locations will see an increase in tides, but unless Hermine becomes stronger than expected not much in the way of coastal flooding is expected. Tropical breezes in the 15-20 mph range will be quite common through Tuesday. The outer rains from this system will begin to impact the region this afternoon, and continue off and on through Wednesday.
...Tropical Storm Hermine Advisory...
10a.m. CDT Monday, September 6, 2010
...Hermine, the Eighth Named Storm of the 2010 Season, Strengthens & is Bound for the Rio Grande Valley...
Latitude: 23.4 N
Longitude: 95.8 W
This places the center of Hermine about 130 miles ESE of La Pesca, Mexico & 210 miles SSE of Brownsville, Texas.
Maximum Sustained Winds: 50 mph w/ higher gusts. Additional strengthening is expected until landfall on Tuesday, and Hermine could become a minimal hurricane before landfall. Tropical storm force winds extend outward to 105 miles from the center.
Movement: NNW or 340 degrees @ 13 mph. This general motion is forecast to continue for the next day or two, and this will take the center of circulation inland somewhere across the Rio Grande Valley of Northeastern Mexico or Deep South Texas Tuesday morning.
Minimum Central Pressure: 29.47" or 998 mb.
Watches/Warnings...A Tropical Storm Warning is in effect from La Pesca, Mexico Northward to Port O'Connor, Texas. A Hurricane Watch is in effect from Rio San Fernando, Mexico Northward to Baffin Bay, Texas.
Rainfall...Rainfall totals of 4-8" are expected across NE Mexico and S Texas with isolated higher amounts in excess of 12" in the higher elevations of Northern Mexico. This will lead to life-threatening flash-floods and mudslides.
Wind...Tropical storm force winds will reach the warning area later today.
Storm surge...Storm surge levels will be in the 2-4' range along and to the North of where the center of Hermine makes landfall Tuesday.
The next update from the National Hurricane Center comes at 1p.m. CDT, followed by the next complete advisory at 4p.m. CDT. My next update will come shortly after the 4p.m. advisory, unless anything significant changes before that time. Look for the official forecast discussion and package tonight as well.
Enjoy your Labor Day & God bless!
-DM-
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