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LOCAL IMPACTS FROM “IDA” FOR JACKSONVILLE/NE FL./SE GA.:
* anyone living along the Gulf Coast or with travel plans along the Gulf Coast needs to stay up to date on the daily forecasts. Of particular concern: Mississippi & Louisiana but Alabama & Texas too.
* the most harsh conditions – hurricane force winds, storm surge, flooding & tornadoes will occur Sun. afternoon through early Mon. for Louisiana.
* realize that major impacts – flooding & tornadoes – will occur well inland through at least the middle of the week
* from the New Orleans N.W.S.: “This is a very dangerous situation that should be taken very seriously, so listening to your local officials could be life dependent! If you are in areas with evacuation orders; it is crucial that you adhere to them and leave now. Any additional hurricane preparations should be RUSHED and FINALIZED!”
* one last word of caution: making evacuation decisions based on past storms can be a very dangerous proposition.
REMEMBER WHEN A TROPICAL STORM OR HURRICANE IS APPROACHING: Taping windows is *NOT* helpful & will not keep glass from breaking… & realize the cone is the average forecast error over a given time – out to 5 days – & *does not* indicate the width of the storm &/or damage therefore do not become fixated on the center of a tropical system.
Hurricane WARNING & storm surge WARNING for Louisiana & Mississippi…..
The forecast of a major hurricane continues for the Central Gulf Coast with particular focus on Louisiana/Mississippi with a landfall Sunday afternoon.
Ida was a tropical wave originated off of Africa & has been steadily marching west waiting for a more favorable environment (less dust, more moist atmosphere & less shear). It seems the wave has found that more favorable area – upgraded to t.d. #9 Thu. morning then t.s. “Ida” late Thu…. & a hurricane early Fri. afternoon followed by a landfall on the Island of Youth then Western Cuba Fri. evening – which becomes even more conducive for strengthening over the Gulf through the weekend (see images below). In fact, a warm “eddy” is over the Gulf of Mexico – similar to 2005 [Katrina & Rita] – & Ida should move over or very near this deep, warm water through the weekend. The only other question is if Ida can take full advantage of the very favorable conditions considering the storm will “only” have about 36-42 hours in total to strengthen. However, the rapid strengthening cycle appears to be underway late Sat. as Ida encounters the moist atmosphere, lower shear & warm water to develop into a significant hurricane with at least a Cat. 3/4 at landfall. Remember some of the more significant U.S. landfalling hurricanes strengthened over a short period of time including Michael, Andrew, Camille & the 1935 Labor Day hurricane to name just a few.
Once mature, Ida may go through structure/intensity phases based on eyeball replacement cycles which, in turn, will impact the ultimate intensity at landfall. Perhaps the best case scenario would be one where an eyewall replacement occurs within 5-10 hours of landfall. However, due to the late intensification process & swift movement, we may not get that kind of luck.
Forecast models have steadied the trend north (vs. Texas) & remain insistent on intense development of Ida with a landfall on the Louisiana coast near/justs west of New Orleans Sunday afternoon/evening. This will continue the string of “bad luck” for Louisiana after 3 hurricanes & 1 tropical storm landfall last year in addition to tropical storm Claudette this year. The UKMET model has trended the same way though is still a little more west & a bit slower.
Ida briefly moved over Western Cuba Fri. night in what was little more than a speed bump for the storm. The hurricane is over the Gulf of Mexico where conditions are quite ripe for strengthening with continued concern about a landfall while the storm is at or nearing its peak intensity – the most dangerous kind of all.
The track looks to be in-between Fred from early last week (turn toward the north with a landfall along the NE Gulf coast) & Grace late last week (due west into Mexico because of a strong ridge). A soft spot or alleyway has indeed formed over the Northern Gulf which will allow the north/northwest turn through Sunday followed by a turn north then northeast at & after landfall.
Double digit storm surge is forecast to occur just to the east of the eye where waves may exceed 40 feet! (based on a Cat. 4 at landfall). Rainfall of 1-2 feet on top of saturated ground will add to the water/flooding woes. Once inland, very heavy rain, flooding & a few tornadoes will extend far to the north & northeast including parts of the Tennessee Valley, Lower Ohio Valley & Mid-Atlantic states.
‘I’ is rather notorious over the years & is the most retired letter of the Atlantic seasonal alphabet. Since 1955, there have been 11 ‘I’ names retired including Iris, Isidore, Isabel & Ivan in consecutive years from 2001-’04. Most recently Irma was retired in 2017 & Iota in 2020. Tied for second in retired letters is ‘C’ & ‘F’ with nine each.
Again – anyone living along the Gulf Coast &/or traveling to the area & well as along the path well inland should stay up to date on the latest forecasts/development every single day through early next week.
Ida’s remnants + a stalled front will combine to make for a potentially serious flash flood situation well inland – as far north as the Tennessee Valley & Ohio River as well as parts of the Mid Atlantic:
500 mb (~30,000 feet) forecast map below for Sunday, 08/29. Note the weakness along the Gulf Coast with a somewhat soft ridge/high pressure along the U.S. east coast while an trough of low pressure moves into the Midwest. Just how weak the high pressure near the east coast is will be critical on how far north & east ‘99-L’ might track.
Deep oceanic heat content – really warm eddy over the Central Gulf is reminiscent of the set-up for Katrina in 2005:
As one would expect in late Aug…. bath-like sea surface temps.:
Decreasing shear up to landfall (but some upper level high pressure/ventilation):
Plenty of moisture (yellow & orange is dry air):
“Morphed Integrated Microwave Imagery” from CIMSS nicely shows the change in structure & intensity of Ida:
South Florida Water Management District:
Eerie similarities to “Katrina” in 2005 when it comes to the Gulf ocean temps./profile. From “Application of Oceanic Heat Content Estimation to Operational Forecasting of Recent Atlantic Category 5 Hurricanes” by Mainelli, Demaria, Goni:
Lots of oil rigs to be affected by Ida over the Northern Gulf so expect a “bump at the pump” in the coming days depending on how things play out.
Elsewhere over the Atlantic … tropical depression #10 formed early Sat. & has a good chance to become “Julian” preceded by another wave east of Bermuda that has become tropical depression #11 & may very well become “Kate”. Neither of these systems will make much progress west even staying well southeast & east of Bermuda. For right now, the Bermuda High across the Atlantic is displaced to the northeast into early Sept. – important for any potential long track tropical systems coming out of the deep tropics. The good news is that if the Bermuda High stays weaker, it will be difficult for a long track tropical cyclone to make all the way across the Atlantic… at least for now.
We’re now just a couple of weeks from the peak of the hurricane season (Sept. 10), so just from a climatological point, we should see an uptick in Atlantic activity. But there are also other indications to track including the MJO, seasonally warm sea surface temps. & rather impressive deep oceanic heat content.
Sea surface temps. across the Atlantic are now near to above avg. across much of the basin (2nd image below) & – even more importantly – deep oceanic heat content is becoming impressive & the “equivalent oceanic heat content” – namely depth averaged temperature in the upper 300 m (~984 feet) – is even more impressive all the way from Africa to the Gulf of Mexico. Such an ocean water temp. pattern is conducive to long track deep tropical Atlantic tropical cyclones & can lead to a more favored regime for rapid intensification cycles. From an AMS research paper in ‘08 Mainelli, DeMaria, Shay, Goni: “Results show that for a large sample of Atlantic storms, the OHC variations have a small but positive impact on the intensity forecasts. However, for intense storms, the effect of the OHC is much more significant, suggestive of its importance on rapid intensification. The OHC input improved the average intensity errors of the SHIPS forecasts by up to 5% for all cases from the category 5 storms, and up to 20% for individual storms, with the maximum improvement for the 72–96-h forecasts. The statistical results obtained indicate that the OHC only becomes important when it has values much larger than that required to support a tropical cyclone.” More recent research continues to indicate similar correlations.
Saharan dust. Dry air – yellow/orange/red/pink. Widespread dust is most common earlier in the hurricane season & is indicative of dry air that can impede the development of tropical cyclones. However, sometimes “wanna’ be” waves will just wait until they get to the other side of the plume then try to develop if everything else happens to be favorable.
2021 names….. “Julian” is the next name on the Atlantic list (names are picked at random by the World Meteorological Organization… repeat every 6 years… historic storms are retired (Florence & Michael in ’18… Dorian in ’19 & Laura, Eta & Iota in ‘20). Last year – 2020 – had a record 30 named storms. The WMO decided beginning in 2021 that the Greek alphabet will be no longer used & instead there will be a supplemental list of names if the first list is exhausted (has only happened twice – 2005 & 2020). More on the history of naming tropical cyclones * here *.
Mid & upper level wind shear (enemy of tropical cyclones) analysis (CIMMS). The red lines indicate strong shear:
Water vapor imagery (dark blue indicates dry air):
Deep oceanic heat content continues to increase across the Gulf, Caribbean & deep tropical Atlantic & has become pretty impressive from the Central/NW Caribbean into the Gulf of Mexico:
Sea surface temp. anomalies:
SE U.S. surface map:
Surface analysis centered on the tropical Atlantic:
Surface analysis of the Gulf:
Atlantic Basin wave forecast for 24, 48 & 72 hours respectively:
The East Pacific:
Nora is hugging the coast of Mexico & will continue to impact the Central & NW Mexican coast as well as the Baja of California. Eventually – from the middle through the end of next week – tropical moisture will stream northward bringing possible flooding to Arizona & New Mexico perhaps as far north as parts of the Rocky Mountain states:
West Pacific IR satellite:
Global tropical activity:
Cox Media Group