Hurricane Ida expected to come inland into Florida as a transitioning extratropical cyclone

Hurricane Ida has taken advantage of the ample moisture in the western Caribbean to become a category one storm.  Ida has little time left to absorb the energy before it enters the less-favorable Gulf of Mexico.

Conditions in the GOM, however, would support a category one hurricane provided upper-level conditions remained favorable – no dry air enters Ida, Ida maintains convection, and shear remains under 20kts (23mph or 37kph).

The NHC mentioned in the 08/0900Z advisory package that due to Ida’s expectations of becoming extratropical in the northern Gulf that it likely would leave any weather advisories to the local National Weather Service offices.

However, several computer models are indicating Ida will come ashore the north central Gulf coast region as a minimal hurricane.  The NHC could not possibly allow not issuing watches and warnings for the region and I would suspect they will be hoisted later today – at least tropical storm watches.

Ida is expected to mingle with an upper-level ridge that will bring strong wind conditions indirectly associated with Ida to the Gulf coast region as early as today.  Therefore, gale wind warnings and coastal flood watches and warnings have been issued for portions of the Louisiana/Mississippi/Alabama/Florida Gulf coast.

Based on latest model trends, it seems more likely Ida will make a landfall in the central Gulf coast region.  the 08/0900Z forecast from the NHC took Ida dangerously close to Florida’s western panhandle as an extratropical system with winds near 45kts (52mph or 83kph).

It is my opinion residents in this area should be prepared for a hurricane based on forecast conditions, sea conditions, and timing issues of any extratropcial transition.

The following storm details are based on data and conditions obtained between 7:00 AM and 9:00 AM CST, including the 08/1500Z National Hurricane Center advisory package.

Hurricane Ida Details

• as of 08/1500Z (9:00 AM CST):
  • located 80 miles west-southwest of the western tip of Cuba;
  • moving northwest (320°) at 9kts (10mph or 17kph);
  • winds are 80kts (92mph or 148kph) with gusts to 100kts (115mph or 185kph);
  • pressure is 983mb (29.03in);
  • eye is 20miles (37km) wide;
  • tropical storm-force winds extend up to 120 miles to the northeast and as little as 40 miles to the southwest;
  • hurricane-force winds extend 15 miles to the north;

Hurricane Ida Forecast Path

• Hurricane Ida is forecast as of 08/1500Z to continue a north-northwest track to approximately 50 miles south of Plaquemines Parish, Louisiana Monday afternoon, local time;
• As Ida passes Plaquemines, it is expected to begin undergoing an extratropical transition but still pack minimal hurricane-force winds;
• Ida is forecast to come inland around Santa Rosa Island, Florida late Tuesday, local time, as a strong extratropical cyclone;
• Ida is expected to enter the Atlantic coast off Jacksonville early Thursday as a weak extratropical cyclone;

Current watches and warnings

As of 12:00 UTC, 6:00 AM CST:

• Tropical storm watch for:
  • Isle of Youth, Cuba;
• Tropical storm warning for:
  • Punta Allen north to Playa Del Carmen, Quintana Roo;
  • Cabo Catoche west to San Felipe;
  • Pinar Del Rio province, Cuba;
• Hurricane watch for:
  • Tulum, Quintana Roo to Playa Del Carmen, Quintana Roo;
  • Grand Isle, LA to MS/AL border – does not include New Orleans;
• Hurricane warning for:
  • Playa Del Carmen, Quintana Roo to Cabo Catoche, Quintana Roo;

Coastal flood warnings are in effect for all coastal parishes and counties of Louisiana and Mississippi east of Terrebonne Parish, Louisiana.

Coastal flood watches are in effect for all coastal counties of Alabama  and Florida east of Okaloosa County, Florida.

Gale warnings are in effect for offshore waters.

The National Hurricane Center said in the 08/0900Z storm discussion (#17) that since Ida is expected to undergo an extratropical transition prior to tropical storm-force winds affecting the Gulf coast, local NWS offices will be issuing the appropriate advisories.

This, as I would take it, likely means that unless atmospheric conditions change considerably, no tropical storm or hurricane watches or warnings will be issued for the Gulf coast.

Instead, gale warnings and high wind warnings will likely be posted possibly as early as this afternoon for coastal and inland counties and parishes.

Current Weather Conditions

The following are the most recent surface conditions obtained in the past three hours within 150miles (278km) from Hurricane Ida’s 08/1200Z position, 20.8°N, 85.7°W:

Station	Time	Location	Pressure	Wind	Waves	Air Temp	Sea Temp	Dewpoint
42056	1250Z, 6:50 AM CST	66nm SE (147°)	1005mb (29.67in)	29kts (33mph or 54kph), gusts 33kts (38mph or 61kph)	11ft @ 8 sec	28°C (82°F)	29°C (84°F)	25°C (77°F)
SHIP	12:00Z, 6:00 AM CST	145nm NE (30°)	1010mb (29.83in)	35kts (40mph or 65kph)	13ft @ 3 sec	25°C (77°F)	29°C (84°F)	N/A

Sea Surface Conditions

• SSTs:
  • Hurricane Ida is currently over 31°C (88°F) SSTs;
  • as Ida passes through the Yucatan Channel later tonight, those SSTs will drop to 27°C (81°F);
  • early tomorrow morning, Ida will pass over a subtropical region of SSTs below 26°C (79°F);
  • thereafter, the storm will get back over waters above 26°C (79°F) for a short period before hitting subtropical waters again shortly thereafter which Ida will remain over the rest of the forecast period;
• OHC:
  • Ida is passing over high OHC values of 110 kJ cm²;
  • OHC values will drop below 50 kJ cm² as it passes the Yucatan Channel;
  • the last three days of the forecast period Ida will be over OHC values less than 30 kJ cm²;

Ida has just about 12 more hours to take advantage of the energy available.  Gulf of Mexico waters will be supportive for Ida without much weakening.  However, no strengthening should be expected because of oceanic conditions after the 12-hour period.

Satellite Presentation

• GOES IR color imagery as of 08/1415Z (8:15 AM CST) showed convection as cold as -90°C (-130°F) over the center of circulation (COC);
• water vapor imagery at the same time shows low-to-mid-level moisture on the periphery of Ida with higher moisture to the north and a moisture channel extending eastward across Cuba towards Hispaniola; if upper-level conditions remained favorable and Ida could tap into the moisture in the southwestern Gulf of Mexico, it would be enough to continue to support convective development;
• a 08/1159Z (5:59 AM CST) SSM\I (85GHz) overpass showed limited convection in the northern quadrant and an open eyewall in the southeastern quadrant – perhaps due to a little dry air getting into the system; if that’s the case, Ida would not be able to strengthen much over the next 12 hours;
• the 37GHz color composite of the previously mentioned pass shows the deeper moisture to the northeastern quadrant and in feeder bands to the east;

Atmospheric Conditions

• UW-CIMSS, as of 08/1200Z (6:00 AM CST), lists upper-level wind shear over Ida above 10kts (12mph or 19kph) from the southwest;
• mid-level wind shear is from the southwest as much as 30kts (35mph or 56kph) in the southeastern quadrant;
• upper-level divergence is minimal over Ida at the present time and should decrease even more as Ida enters the Gulf of Mexico;

Computer Forecast Models

• EMCWF 08/0000Z:  shows the remnants of Hurricane Ida inland over Mississippi in 72 hours; dissolves the storm into frontal trough in 96 hours off the eastern seaboard;
• CMC 08/0000Z:  the Canadian is slower than the official NHC forecast having Ida 150 miles south-southwest of the NHC’s position at 36 hours; the CMC continues to bring Ida into the Louisiana/Mississippi region early Tuesday, local time, as a strong tropical storm or hurricane;
• GFS 08/0600Z: the GFS seems to break Ida open at the 24-hour period due to shear; the GFS then takes the remnants of Ida into the Lousiana/Mississippi coasts late Monday night or early Tuesday morning, local time; as with the CMC and EMCWF, the GFS proceeds to take the remnants across the southeast United States off the Atlantic seaboard;
• GFDL 08/0600Z: maintains Ida as a hurricane through the central Gulf of Mexico with a landfall near the Mississippi/Alabama border; intensity-wise, the GFDL has Ida as a category two hurricane with 90kts (104mph or 167kph) – I would say this is an overestimate and I strongly doubt Ida would be more than a minimal hurricane at the time of landfall;
• HWRF 08/0600Z: nearly identical to the GFDL with landfall around Pensacola as a category two hurricane;
• other track models as of 08/1200Z (6:00 AM CST) are showing landfall in the same region around 48 hours;
• intensity guidance as of 08/1200Z shows no weakening for the first 24 hours;