NAVY:


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JEFF MASTERS:
Ida strengthens, could be a hurricane for the Yucatan

Tropical Storm Ida is slowly strengthening, as it heads north-northwest towards an encounter with Mexico's Yucatan Peninsula. Infrared satellite loops show that Ida's heavy thunderstorms are expanding in area, and the cloud tops are cooling, indicating that the updrafts in the storm are growing stronger and pushing higher into the atmosphere. Wind shear is a moderate 15 - 20 knots, and is forecast to remain moderate through Sunday night. SSTs are a warm 29°C, and the total ocean heat content is over 100 kJ/cm^2, which is very favorable for intensification. The rains have ended over Nicaragua and Honduras, and Ida dumped up to eleven inches of rain along the coast in Nicaragua, causing flooding that damaged thousands of homes, but caused no deaths or injuries as of yet.


Figure 1. Satellite-estimated rainfall from Ida. The dark red colors (275 mm) represent rainfall in excess of about eleven inches. Image credit: NASA/TRMM project. Wunderground meteorologist Dr. Rob Carver presents another estimate of Ida's precipitation in his blog today.

The forecast for Ida
The moderate wind shear of 15 - 20 knots should allow for continued slow but steady intensification of Ida through Sunday afternoon, as long as the center remains over water. I give Ida a medium (30 - 50% chance) of reaching Category 1 hurricane strength before arriving at the Yucatan, since the total heat content of the ocean in the Western Caribbean is so high. We'll have a better idea of Ida's current strength early this afternoon, when the Hurricane Hunters have had time to investigate the storm.

The current wind speed probabilities for Cozumel give the Mexican resort island a 46% chance of receiving tropical storm-force winds of 39 mph of higher, Sunday or Monday. The odds of receiving hurricane force winds are given as 3%. Given the current trend in organization of Ida, these numbers should probably be bumped up to about 60% and 5%, respectively.

Once Ida crosses into the Gulf of Mexico on Sunday night, the storm will encounter much cooler SSTs and a strong trough of low pressure that will dump cold air into the storm and bring 40 knots of wind shear. This will cause Ida to lose its tropical characteristics and become a powerful extratropical storm with 45 - 55 mph winds. It is highly unlikely that Ida will hit the U.S. as a tropical storm, but it could still bring tropical storm-force winds of 45 mph to the coast next week as an extratropical storm.

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CROWN WEATHER:
Hurricane Ida:
Here is the 6 am Eastern Time/5 am Central Time Information On Hurricane Ida:
Location: 20.8 North Latitude, 85.7 West Longitude.
Maximum Sustained Winds: 90 mph.
Movement: Northwest or 325 Degrees at a forward speed of 12 mph.
Minimum Central Pressure: 983 millibars or 29.03 inches.

Air Force reconnaissance aircraft found a 90 mph hurricane late last night with a 984 millibar central pressure. I expect Ida to strengthen some more today and for it to reach Category 2 strength either today or tonight. The reason for this thinking is because Ida will be over some very warm ocean waters for the next 24 hours or so and the environment is somewhat favorable. I suspect that Ida will peak at between 100 and 105 mph later this afternoon and tonight. As we get into Monday and Tuesday, Ida will start to track into cooler sea surface temperatures during Monday and also into an area of higher wind shear; although I continue to believe that Ida’s forward motion will line up with the southwesterly wind shear and cause a net shear of nearly zero and thus not weaken as quickly as you would normally see. The global models forecast that Ida will start to become extratropical during Tuesday. I’m not convinced that Ida will be extratropical by the time it reaches the northern Gulf coast. The latest GFDL model forecasts that Ida will come ashore as a Category 1 hurricane near Mobile, Alabama late Monday night. The latest HWRF model forecasts that Ida will come ashore as a Category 1 hurricane near Pensacola, Florida around midnight Monday night. In addition, the cyclone phase evolution webpage forecasts that Ida will remain a warm cored tropical system right through landfall. So, I have to disagree with the National Hurricane Center and I do believe that Ida will still be a tropical system and come ashore as a tropical system.

Ida is currently tracking northwest at a forward speed of 12 mph. Ida is forecast to come very close to the northeastern tip of the Yucatan Peninsula by early this afternoon and Ida will then track into the Gulf of Mexico tonight and then speed up in forward speed on Monday. Based on the latest model guidance and also the strength of the incoming trough, I have to disagree with the NHC on the timing of Ida. I think the storm will reach the northern Gulf much quicker than the NHC forecast; in fact, the GFS model forecasts Ida will make landfall in the extreme western Florida panhandle on Tuesday morning. The European model forecasts that Ida will be ashore on Monday night as does the GFDL, HWRF and Canadian models. So, my thinking is that Ida will be in the northern Gulf of Mexico by Monday evening and then come ashore somewhere between Apalachee Bay, Florida and Gulfport, Mississippi with the most likely area being between Mobile, Alabama and Fort Walton Beach, Florida. The time of landfall will be between midnight Monday night and 9 am Tuesday morning. The strength of Ida at landfall looks to be somewhere between a 65 mph tropical storm and a 80 mph Category 1 hurricane.

The northeastern Yucatan Peninsula, including Cancun and Cozumel will have hurricane conditions today, especially late this morning into this afternoon. Very heavy rainfall, hurricane force winds and a storm surge of up to 4 feet above ground level is likely in the northeastern Yucatan Peninsula today.

Ida will effect much of the northern Gulf coast with heavy rainfall of 2 to 6 inches, tropical storm force winds, high seas and coastal flooding starting on Monday and continuing through Tuesday. I understand, but respectfully disagree, on the National Hurricane Center letting the local NWS offices handle Ida with local watches and warnings and not issue a Tropical Storm or even a Hurricane Watch for parts of the northern Gulf Coast. So, residents and vacationers along the northern Gulf coast should closely monitor local media or their local National Weather Service office for the latest watches and warnings.

this morning we get the classic view of a storm heading thru the chute between cancun and cuba.