HURRICANE IDA HIGH PROBABLITY TO REACH CATEGORY 4

There is no doubt in my mind, based upon looking at the latest data, that recently upgraded hurricane IDA will achieve category 4 status at some point over the next 48 hours. There is still uncertainty as to whether it will be a category 4 when it makes landfall on the Central Louisiana coast but it will clearly become a category 4 hurricane. There is also a possibility that it could reach Category 5 status as well.

In addition this update shows that there is little chance that IDA will shift to the West and make Landfall on the upper Texas coast — that is to say near the Louisiana Texas border over to the Galveston Bay area. The vast majority of the data shows that it’s going to make landfall in the central Louisiana coast. A slight jog to the west is still possible but the model agreement is extremely strong.

Inland the flooding will be quite serious because the Delta and the Gulf Coast areas are quite saturated and have been for most of the summer. Indeed this is the only area in the CONUS that has seen saturated ground conditions because of continued above normal rainfall for most of the spring and summer. Obviously this has major implications for the Inland locations with regard to power infrastructure damage. But IDA’s Track size and intensity also has major implications in the agricultural interests because of the amount of soybeans, cotton, and sugar which is grown in the Delta and the increasingly tight supplies of these commodities in the US and throughout the world.

Here is the midday infrared satellite picture and it shows why IDA was upgraded to hurricane at midday. There is a clear “EYE” being detected in the infrared and visible satellite pictures

And here is the Friday afternoon visible satellite picture which is quite impressive.

This image shows the recent track of IDA and we can see the turn to the Northwest is quite prominent end continuous. It looks like the eye is going to go over the Far Western tip of Cuba but that should not cause any significant disruption to the intensification of the structure of the hurricane.

This image shows the recent reconnaissance flight and information found Based upon the 2:30 p.m. report. The minimum sea level pressure has fallen steadily and significantly all day from 997 to 985. Notice that the strongest winds are still on the northern eastern side which is indicative of an immature but developing hurricane.

The reconnaissance data shows that maximum flight level winds found 75 knots or 80 MPH with numerous surface wind speeds 70 to 80mph

The actual forecast track is quite straightforward and not complicated and that is probably the easiest thing to understand with regard to what is happening with IDA. This image shows the recent upper air 500mb pattern across the CONUS. Anyone who has been outside in the past week across the eastern third of the CONUS and the Deep South can tell you that it has been beastly hot day after day and extremely humid. This is because of a monster Ridge in the jet stream that stretches from Texas to Kansas, across the Deep South the Ohio valley, then through the Middle Atlantic States into the western Atlantic Ocean. It is the position and shape of this feature which has been driving IDA to the WNW.

However over the past 36 a strong trough in the jet stream and surface cold front has been moving in from the Rockies and pushing into the upper Plains and the Upper Midwest. This is dislodging or weakening the western side of the Ridge. The heat Dome itself is centered across Virginia and the Carolinas and this is where temperatures have been the hottest for the past several days in the eastern half of the country. Hurricane IDA is detecting that the Heat Ridge is under attack and that the western side is weakening. This has allowed IDA to turn more to the NW but there is still a heat DOME centered in the southeastern states that is anchored in the Carolinas and Virginia. So IDA is now turning around the western periphery of this Heat DOME.

In other words, the hurricane is going around the western periphery of the heat Dome. During the next two days, the heat DOME will slide east, which will allow the hurricane to turn to the north as it follows around the Western periphery of the Dome. When IDA makes landfall, it probably will be headed due N and within 24 hours after landfall, IDA will make a turn to the NE moving into Mississippi and then eventually either far northern Alabama or Tennessee as a weakened tropical storm or tropical depression with a tremendous amount of rain.’

There are several reasons why WxRisk — and others- are very concerned about the potential for explosive deepening of hurricane IDA into a monstrously large and Powerful category four or even Category 5 hurricane as it approaches the Louisiana coast on Sunday.

First and most obvious are the record warm ocean water temperatures in the Gulf of Mexico. Most people know that extremely warm ocean water temperature has become the essential fuel for tropical Cyclones whether it’s in the Atlantic or the Pacific or the Indian Ocean.

Another feature which is very important is the development of HIGH pressure at the upper levels of the atmosphere , usually at the 200 MB level. This is the heart of the jet stream and when you have strong HIGH pressure at this level, tropical systems which move underneath them are energized because the HIGH pressure at the top of the hurricane helps the circulation of the hurricane. The HIGH increases the circulation of the air coming out of the eye at the top of the hurricane which in turn always causes rapid and dramatic intensification.

Indeed the hurricane SHIPS model, which is one of the primary models used by the hurricane center to figure out intensity of hurricanes and how fast it can intensify, is absolutely going bonkers with the intensification of IDA this weekend. It clearly shows maximum winds reaching 127 knots or 145 mph which is a very solid category 4 hurricane. Not only does the SHIPS model show an ideal perfect atmosphere in the Gulf of Mexico with absolutely no shear of any kind but it shows a 43% chance of intensification of greater than 65 knots over the next three days . Amazingly that’s actually the highest probability with respect to intensification.

Also many of the hurricane models such as the HWRF which almost always over does everything is also showing a 939MB hurricane hitting the Central Louisiana coast on Sunday night.

In our opinion the rainfall forecast from the various models for the Delta Region — the eastern half of Louisiana. all of Mississippi, western Alabama, and eastern Tennessee are probably under done.

One final concern is that once IDA has moved Inland and turns to the East, the system, even though it will be greatly weakened and just a large rainstorm, could pose a tornado threat for much of Tennessee, North Carolina, and the southern half of Virginia on September 2nd or 3rd. Experience shows that when you have powerful intense hurricanes which have large circulations that move out of the Appalachian Mountains, there is an enhanced or elevated risk of tornadoes in the Middle Atlantic region east of the mountains of Virginia and North Carolina. We saw this particularly with the remains of hurricane Florence which caused a significant tornado outbreak in these areas when the system moved out of the Appalachian Mountains into Virginia and Maryland. There were similar occurrences of tornado outbreaks of some significance in the Middle Atlantic region east of the mountains from Hurricane Frances and Ivan in the 2004 hurricane season