Sunday, November 8, 2009

The Latest on Hurricane Ida...

Sunday, November 8, 2009

I will have the complete forecast discussion later tonight, but I wanted to update everyone on Hurricane Ida. This really is amazing to see what is going on the Gulf in early November.

I will post the latest advisory and information from the National Hurricane Center shortly, but first here is my assessment of the situation.

First, I should note that even though there are some changes to the forecast track of Ida, it will not change the weather immensely across our area. We're still on track for rain tonight through Monday, not associated with Ida. The non-tropical low in the Western Gulf will bring rain into the area tonight ahead of a cold front which will move through late Monday into early Tuesday.

Ida has progressively strengthened since it emerged into the warm waters of the Western Caribbean, and is now emerging into the SE Gulf just to the NE of the NE tip of the Yucatan Peninsula of Mexico. It is now a category 2 storm with 100 mph winds. Ida is making steady progress to the NNW at 10 mph, and this motion will continue tonight as Ida moves further into the Southern Gulf. Winds and seas are already increasing over the Gulf waters, and will continue to do so through the night. Slight additional strengthening is expected tonight as Ida remains in a favorable environment for strengthening to occur for a little while longer. It is out of the realm of possibility that Ida will achieve major hurricane status before the weakening trend commences Monday, but this is not currently forecast. Given the stready-state strengthening that is ongoing, it wouldn't surprise me quite honestly. Ida will accelerate in forward speed on Monday as it begins to feel the influence of an approaching trough and associated cold front moving into SE Texas. Wind shear over the Gulf will also present a hostile environment for Ida's survival. Cooler water temperatures from this season's cool fronts is also in place over the Central and Northern Gulf, and water temperatures across that region are not supportive of tropical development.

It is the reasons cited above that will result in a transitioning phase for Ida. Ida will transform from its current tropical stage to extratropical beginning Monday. The question is will it completely lose its tropical characteristics before making a Northern Gulf coast landfall on Tuesday. The forecasted path of Ida brings it just E of the Mouth of the Mississippi River Monday evening into Monday night as a weakening hurricane and transitioning system. Ida is currently forecast to complete the transition to extratropical just offshore of the Northern Gulf coast on Tuesday before making landfall as a strong extratropical system near Pensacola, FL Tuesday afternoon. The highly sheared environment will begin to tear apart the storm, and force the weakening trend. The storm will accelerate as it feels the effects of the strong upper level SW winds out ahead of the advancing trough. Near or shortly after landfall, Ida will merge with the front and move parallel to the coast over the Florida Panhandle or Southern Georgia.

On this current forecasted track, SE Louisiana will receive a glancing blow from Ida. Tropical storm force winds will be felt across portions of SE Louisiana, but Ida is very compact, and at this time I only expect 40-50 mph winds at best for the New Orleans Metro Area, including the Northshore. Some hurricane force winds of 75-85 mph may be felt briefly across the extreme portions of SE Louisiana to the S and E of New Orleans. The coastline of Mississippi, Alabama, and the Florida Panhandle will likely have a better chance of experiencing any hurricane force winds. With the expected acceleration, the storm will move very quickly, and threat to SE Louisiana will be over with entirely Tuesday afternoon. The main threats for the entire Gulf Coast will be heavy rain and flooding. Locations along and to the right of the center of circulation could see 5-10" of rainfall, coastal and inland flooding. Minor wind damage is expected with the strongest wind confined to a small area near the center 65-80 mph. Lighter wind speeds of 40-60 mph can be expected further away from the center. Model consensus is very consistent in a path similar to the official forecast from the National Hurricane Center.

A Hurricane Watch has been issued for the Gulf Coast from Grand Isle, LA all the way Eastward to Mexico Beach, Florida. A Hurricane Warning is in effect for the Yucatan Peninsula from Cabo Catoche to Playa del Carmen. A Hurricane Watch is in effect for the Yucatan Peninsula of Mexico from Playa del Carmen to Tulum. The Hurricane Watch along the Gulf Coast doesn't include New Orleans.

A Tropical Storm Warning is in effect from Punta Allen to Playa del Carmen and from Cabo Catoche to San Felipe on the Yucatan Peninsula. A Tropical Storm Warning is in effect for the Cuban Province of Pinar del Rio, and a Tropical Storm Watch is in effect for the Isle of Youth.

In Louisiana, the National Weather Service in Slidell has issued some inland Tropical Storm and Hurricane Watches as well. A Hurricane Wind Watch is in effect until 6p.m. Tuesday for Lower Jefferson, Plaquemines, and St. Bernard Parishes in SE Louisiana as well as Hancock, Harrison, and Jackson Counties on the Mississippi Coast.

A Tropical Storm Wind Watch is in effect until 6p.m. Tuesday for the following locations: Lower Lafourche, Lower Terrebonne, Orleans, St. Charles, St. John the Baptist, St. Tammany, Tangipahoa, Upper Jefferson, Upper Lafourche, and Upper Terrebonne Parishes in SE Louisiana, and Pearl River County in Southern Mississippi.

A Flood Watch is in effect until 6p.m. Tuesday for the same areas mentioned above as well as Washington Parish in SE Louisiana.

Coastal Flood Watches are in effect for all of SE Louisiana and South Mississippi as well. Storm surge flooding is expected along and to the right of the the center of Ida. A Coastal Flood Watch is also in effect for SW Louisiana and SE Texas through Monday, but this is not directly associated with the effects of Ida.

Here is the latest advisory from the National Hurricane Center:

Hurricane Ida 3p.m. Sunday, November 8, 2009

Latitude:    22.2 N
Longitude: 86.3 W
This is about 95 miles WNW of the Western tip of Cuba, and about 510 miles SSE of the Mouth of the Mississippi River.

Winds: 100 mph-Category 2. Little change in strength is expected through tonight, and weakening is expected to begin Monday. Ida is a very compact storm with hurricane force winds extending outward to 35 miles from the center while tropical storm force winds extend outward to 140 miles from the center.

Movement: NNW at 10 mph. A gradual turn towards the North, and an increase in forward speed is expected Monday. Ida will be near the Northern Gulf Coast on Tuesday.

Pressure: 28.82" or 976 mb.

















 















The next advisory from the National Hurricane Center will be issued at 6p.m. CST Sunday.


I will have more information on Ida as well as the complete forecast discussion for SW Louisiana tonight.

-DM-

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