Tropical Depression Ida, Tropical Storm Kate, and the Atlantic Blob: 30 August, Update A

And more importantly, Goodbye Ida!! She is now a Tropical Depression, last seen over central Mississippi at around 33.3N, 89.5W, heading NE at 10mph. Winds have decreased to 35 mph, central pressure is around 998mb, so she is fairly weak but still has quite a bit of rain which you can see is falling over a number of states in the US:

The full extent of damages is still not known yet of course, and it is extensive, but clean up and recovery has slowly started.

 

Some of you wondered how unusual this hurricane was in keeping her eye for many hours after landfall. It is not the first time we have seen this. Strong storms that come ashore over any swampy water (such as in southern Louisiana) have the same behaviour because they are going over an area with warm water (a 'brown ocean'). Another notable example was Hurricane Andrew in 1992 which made landfall in Miami as a cat 5 storm and crossed the southern Everglades, maintaining a solid eye, and emerging back in the Gulf of Mexico as a cat 4 storm. 

In many ways, this storm was really not unusual - it's the time of year for strong storms and we know that they reach this part of the Gulf. It also crossed that Loop Current Eddy (deep warm water) so, because the conditions in the atmosphere were 'good', it was inevitable that she would intensify. 

The only unusual aspect that I noticed was that we don't normally see such strong storms at this time of year get named so close to landfall - usually we see the August/September/October storms coming across the Atlantic and they become hurricanes or named Tropical Storms much earlier in their track. We did see this Atlantic Blobette coming across the Atlantic (like TD10 - now Tropical Storm Kate), but it wasn't upgraded to a Tropical Depression until Thursday afternoon in the western Caribbean. We normally see Caribbean and Gulf of Mexico storms pop up early and late in the season - when the storms are not so strong.

In this case, there was a lot of dry air - that Saharan Air Layer - which kept her convection and development in check. However, she did have considerable circulation so as soon as she got away from that, she was over very warm water and blossomed quickly.

This is my last note on Ida. 

Tropical Storm Kate

This was TD10 yesterday and was named this morning. She is barely a Tropical Storm with winds of 40mph, central pressure 1003mb. There isn't a lot of convection, but what little there is you can see in the satellite imagery above. She is at 22.7N, 50.9N. and is moving N at 6mph:

The forecast is that she will be a TD tomorrow. She is under some wind shear and dry air, and has very little circulation in the mid-troposphere, so I would say she is actually already a Tropical Depression. 

There is one more Atlantic Blob that just emerged from Africa - it does have some circulation in the lower half of the troposphere (more than Kate) but it isn't quite developed enough to be a Tropical Depression.

Oh, and in case you were wondering what happened to Tropical Storm Julian - well he became post-tropical today as expected and went away too. Just like that. 

That's all for today! 

Toodle pip, 

J. 

Blogs archived at http://jyotikastorms.blogspot.com/

Twitter @JyovianStorm

--------------------------------------

DISCLAIMER:

These remarks are just what I think/see regarding tropical storms - not the opinion of any organization I represent. If you are making an evacuation decision, please heed your local emergency management and the National Hurricane Center's official forecast and local weather service announcements. This is not an official forecast. If I "run away, run away" (Monty Python), I'll let you know.

Hurricane Ida, Tropical Storm Julian, and TD 10: 29 August, Update A

Oh deary me! Ida continued to intensify even after crossing the Loop Current Eddy and has now, finally, made landfall as a strong cat 4 storm with estimated winds of 150mph and a very low central pressure of 933mb (Cat 4 range: 130-156mph), somewhat more robust than all the projections. 

She is currently inland at 29.5N, 90.6W, heading NW at 10mph and winds have decreased to 130mph (central pressure is now 938mb). Landfall was around 11am this morning, in southwestern Louisiana, west of New Orleans - in an area which has a lot of low-lying swampland and is not as densely populated as other parts of that coastline:

She had a lot of convection - rain, thunderstorms - and a clear eye which was about 15 nautical miles in diameter (just over 17 miles):

There isn't any large decrease in appearance or circulation (at all levels of the troposphere) since landfall, even though they have lowered her winds. She still has a very solid eye. The slow change is because of those swampy regions she is going over - essentially it's a continuation of the ocean. 

The issue is the storm surge and flooding. Since Katrina, billions of dollars have been put into the levee system around New Orleans, so they should hold up. However, it will take some time for the Lake to drain out so even though the storm has made landfall, there is still a strain. There are parts of the coastline which have seen over 7 ft of storm surge. As I said yesterday, those on the east side of the eye will experience greater surge because water is being pushed on shore, whereas those on the west side will experience less. Here are some storm surge data charts from...

Shell Beach, LA (east side of eye) - water was 7.55ft above normal: 

New Canal Street Station, LA - New Orleans (east side of eye) - water is 3.16ft above normal: 

Grand Isle, LA (nearest station to eye of storm) but still on the east where water was 4.77ft above normal:

Bay Waveland Yacht Club, MS (east side of eye) - water was 6ft above normal:

And from Amerada Pass, LA (west side of eye) - where water was actually 0.36ft below normal:

The news is still emerging of course but we already know that power is out (and the utilities from many states are already ready to go in to help out - thank you!), some damage to buildings, trees etc. The full impact will emerge in a day or two though. 

She is projected to continue heading inland and then turn to the northeast. She has got a lot of rain, so again, if you are in the path inland be prepared for potential flooding - move out of flood zones. 

Tropical Storm Julian 

This was yesterday's TD 11, which did turn out to be a little better developed than TD10. He is a mid-sized TS with winds of 60mph, central pressure 995mb. He does have some convection, as you can see in the northern edge of this satellite image: 

He is currently at 36.7N, 44.6W, heading NE at 24mph. He is expected to continue moving to the northeast over the next few days as a TS:

He will not survive that far north as 'Tropical' Storm but will morph into a Post-Tropical Storm instead (the NHC expect this to take place tomorrow). 

Tropical Depression 10

She is still struggling to develop. She's at 19.7N, 50.4W, heading N at 12mph. She doesn't have a lot of convection, as you can see in the image above. Winds are estimated to be 35mph, central pressure is 1008mb. I'll keep an eye on her. 

That's all for today. Hoping all my friends and wonderful readers are safe post-Ida! 

Toodle pip,

J.

Blogs archived at http://jyotikastorms.blogspot.com/

Twitter @JyovianStorm

--------------------------------------

DISCLAIMER:

These remarks are just what I think/see regarding tropical storms - not the opinion of any organization I represent. If you are making an evacuation decision, please heed your local emergency management and the National Hurricane Center's official forecast and local weather service announcements. This is not an official forecast. If I "run away, run away" (Monty Python), I'll let you know.

Hurricane Ida: 28 August, Update B

Just checking in up on Ida one more time before the end of the day. She is at 27.6N, 88.7W, heading NW at 15mph:

She has been slower to intensify than the NHC expected, but was just upgraded to a weak cat 3 storm with winds of 115mph, central pressure is 955mb (cat 3 range: 111-129mph). I would agree with the cat 3 status - she is a little stronger which we know because the eye is a little steadier, the vorticity (circulation) is even stronger in the upper levels of the troposphere, and the pressure is a lot lower than earlier in the day. 

She is moving over that Loop Current Eddy region and we can see that the deep warm water has strengthened her convection quite a bit: 

The strong thunderstorms and tornado-generating weather in the red area has expanded and now fully encloses the eye. But the storm is already interacting with land - we can see some of the stronger outer bands over the Florida panhandle and along the Alabama coast, dropping a bucket or two of rain here and there. 

However, she has reached the northern edge of that Loop Current Eddy: 

so she won't have too much more deep warm water to cross in a couple more hours, and she won't intensify too much further. They still maintain she will have winds of 130mph at landfall, which means she will be a borderline cat 4 storm (130-156mph). She will most likely be a strong cat 3 - still a major hurricane (cat 3 and higher are major hurricanes). 

She is going to make landfall west of the Mississippi Delta, which means that water levels will increase in New Orleans. As parts of New Orleans are below Sea Level, they have levees. For New Orleans, even though the storm will have made landfall, it will take a day or longer for the water to drain out of Lake Pontchartrain, so I'm sure everyone will be watching and monitoring the levees carefully. Storm surge is now a lot higher than it was earlier today. At Shell Beach, LA, it is already almost 3 ft above normal: 

At New Canal Station in New Orleans, LA, water is almost 2ft above normal:

And at Dauphin Island, AL, water is also almost 1.5ft above normal: 

Good luck to those in Ida's path! Be safe out there! 

(and I see TD 11 has officially been numbered - both TDs are expected to become Tropical Storms tomorrow (Sunday)).

Until tomorrow,

J. 

Blogs archived at http://jyotikastorms.blogspot.com/

Twitter @JyovianStorm

--------------------------------------

DISCLAIMER:

These remarks are just what I think/see regarding tropical storms - not the opinion of any organization I represent. If you are making an evacuation decision, please heed your local emergency management and the National Hurricane Center's official forecast and local weather service announcements. This is not an official forecast. If I "run away, run away" (Monty Python), I'll let you know.

Hurricane Ida, Tropical Depression 10, and the Atlantic Blobette: 28 August, Update A

It's a weekend, so of course Mother Nature is out partying with a few storms here and there! And as it's the weekend, I had a French Lunch (i.e. any lunch which involves red wine :-)). 

Hurricane Ida

Ida has slowly got stronger, which was expected after she cleared Cuba because of low wind shear, generally humid air, and warm sea surface temperatures. The NHC currently peg her as a strong cat 2 hurricane with winds of 105mph, central pressure of 976mb (cat 2 range: 96 - 110mph). I would agree with this cat 2 status because she has an eye (so the winds are stronger than 90mph), but it is fluctuating in size and strength so she's not quite at the major cat 3 or higher level. Here are the visible, infrared, and water vapour satellite images so we can see what is going on. From the visible, we see that the eye is not very clear yet, although it is there, and that this storm is covering the entire eastern half of the Gulf of Mexico - she is quite large...  

As a reminder, the infrared satellite images tell us how cold the tops of the clouds are, which means how strong the rainfall or thunderstorms are (see the <Science Alert!> and <Technical Alert!> double feature here for a full explanation). So, from the infrared, we see that although there are some clouds over the northern Gulf and Florida, a lot of it is just cloudy with some lighter bands of rain (blus/green). There is heavy rain and some thunderstorms (yellow/orange/red) over Georgia, Texas, and along southwest Florida and Cuba, but the bulk of the really heavy rainfall and strongest thunderstorms (red/dark red) is still offshore. We also see that the convection is not evenly spread around the eye yet... 

From the upper atmospheric level water vapour, we can see that the air is humid around the eye and the storm in general, however there appears to be a little drier air being pulled in to her south from the southwest side of the storm...  

From the lower atmospheric water vapour, we can see that drier air a lot more clearly... 

And from all of these images, we can cross-check that the center is where the current forecast track shows (and it is right on track)... she is at 26.3N, 87W heading NW at 16mph. Landfall is expected tomorrow afternoon, which is the 16 year anniversary of Katrina in that part of the world.

Generally, she has been staying to the eastern edge of the Cone of Uncertainty for the last 2 days instead of along the center, so her track after leaving Cuba has been on the eastern edge of the Loop Current, which is why she hasn't intensified as quickly as they thought she would. As a result, the NHC have downgraded her winds at landfall from 140mph to 130mph - from a mid-size cat 4 to barely a cat 4/borderline cat 3 storm (cat 4 range: 130-156mph). The Loop Current map (the depth of water warmer than 26 deg C) is... 

Although she's been on that eastern side of the 'yellow' sliver, she is about to cross over the patch of warmer water that looks like an inverted triangle in the northern Gulf (a Loop Current Eddy). It will take her a few hours to cross this region (unless she speeds up), which means she will continue to get stronger until the early hours of tomorrow morning (unless that dry air from the south really manages to get a foothold).

Her circulation (vorticity) is very strong in all levels of the troposphere. Here is the vorticity map at 850mb (lower level): 

 

At 500mb (mid-level of troposphere):

And at 200mb (the highest level): 

You can see Ida has a good signal in all levels, including at 200mb, which means she is clearly a hurricane and given how robust that is at that high altitude, she's a cat 2. 

For those who are in the northern Gulf, where she makes landfall is important for storm surge.

<Science Alert!> Storm surge is water rising along the coastline as a storm approaches and makes landfall. How high the storm surge is depends on a number of factors: 

1. Storms are low pressure systems, which means that there is low atmospheric pressure. But obviously we don't have a "gap" between the air and the ocean (which are both fluids - one gas and one liquid), so the water 'rises' up to fill that 'gap' which is created by the low atmospheric pressure. So the stronger the storm is, the lower the central pressure, the greater the 'gap' for the water to rise to 'fill'. 

2. Storms are low pressure systems, so in the northern hemisphere they rotate in an anticlockwise direction.  This means generally water will be pushed onshore on the eastern side of the eye, and will be pushed off shore on the western side. Storm surge will be higher on the eastern side. In this case, if Ida makes landfall to the west of the Mississippi Delta, she will push water up the river and towards New Orleans as well as along the coast.

3. Speed of the storm. If a storm is moving quickly, then there is simply less time for water to get pushed onshore before the storm has swung by. Storm surge is greater for slower storms. 

4. Angle of storm approach to land. Depending on if a storm is approaching land directly or at an angle can affect the amount of storm surge because of the direction of the winds. Storms that are heading directly onto shore result in greater storm surge than those that are approaching it from an angle - skirting along the coastline. 

5. Shape of coastline (bays etc). Water can get piled into bays and upstream in estuaries of course. 

6. The depth of the seafloor just off the coast is important. For areas with a shallow seafloor, more water piles up compared to areas where the seafloor is deep just off the coast. 

<End Science Alert!>

To monitor storm surge, use NOAA's tidesandcurrents website (instructions for this website are in the <Technical Alert!> in this post). At the moment, I see storm surge of around 0.5ft in parts of the northern Gulf/Louisiana region. 

Be safe out there - listen to your local emergency managers because each area is different! 

Remember - hide from the wind, run from the water. This means that if you can shelter safely and you aren't in a flood zone, then stay in place. If you are in a flood zone, then try and get out. Water causes the most fatalities in tropical storms. 

And remember to eat the ice cream first in case the power does go out.... 

Tropical Depression 10 & the Atlantic Blobette

TD10 was yesterday's Atlantic Blob and may be the future Julian, but from the vorticity maps, there isn't much of a signal in the mid-levels of the troposphere so he is quite weak at the moment. In fact, the Atlantic Blobette east of Bermuda has more of a signal in the mid-levels than TD 10. They both are fairly weak, but I expect the Atlantic Blobette to be TD11 soon...

I won't say much more about these until they are named. 

More later!
Ciao,

J. 

Blogs archived at http://jyotikastorms.blogspot.com/

Twitter @JyovianStorm

--------------------------------------

DISCLAIMER:

These remarks are just what I think/see regarding tropical storms - not the opinion of any organization I represent. If you are making an evacuation decision, please heed your local emergency management and the National Hurricane Center's official forecast and local weather service announcements. This is not an official forecast. If I "run away, run away" (Monty Python), I'll let you know.

Hurricane Ida, Atlantic Blob and Atlantic Blobette: 27 August, Update A

Well, my friends, Ida pulled herself together pretty quickly today, didn't she? Just in time for the weekend. So...

Hurricane Ida

She is currently at 23N, 84W, heading NW at 15mph and is crossing Cuba a little to the east of the track that they estimated yesterday, which is as expected. However, the track for the next couple of days continues to take her towards the central northern Gulf (as I'm sure everyone around the Gulf knows by now!): 

At the moment, I don't see any reason not to go with the NHC track  - I would still be prepared along the entire northern Gulf coast between TX and Apalachicola, FL. Especially as her rainfall and thundery weather stretches over quite a large area. 

She is currently a weak Cat 1 hurricane with winds of 80mph, central pressure of 989mb (Cat 1 range: 74-95mph). She has got quite a lot of convection still, although we can see that Cuba really helped to take some of that out of her:

There is also some wind shear, which we see from the clouds streaming to the east, however that looks like it will decrease in the Gulf. The NHC are forecasting a major cat 4 hurricane to make landfall late Sunday/early Monday. If she stays on the forecast track, then a strong hurricane is possible. The factors that are controlling her intensity in the Gulf are: 

1. Low wind shear over the Gulf.

2. The air has a lot of water vapour ahead of her, although not at all levels of the atmosphere. In the upper layers of the troposphere, there isn't any dry air (dark purple). This water vapour is a factor in helping her to intensify: 

But there is some drier air (yellow parts) in the lower levels of the atmosphere, which you can see in the satellite image below and is part of the reason that her convection is not as robust as it was when she was crossing Cuba:

If that dry air continues, then her intensification will be slow. But there is a lot of convection so I am not sure it will continue to inhibit her for much longer. 

3. But the biggest reason why they are thinking she will intensify quickly is because not only are the Gulf sea surface temperatures warmer than 28 deg C, the path she is forecast to take means that she will pass directly over the Loop Current over the next 2 days. The Loop Current is part of the Gulf Stream system and has a lot of deep warm water. This means that as she churns up the water underneath her, she is bringing up more warm water which keeps feeding her and helps her to intensify. A map of the depth of the 26 deg C and warmer water is here... 

If you overlay the track path, you can see that she is projected to go over the deeper warm water all the way into the northern Gulf (yellow means water warmer than 26 deg C is in the upper 100m of the water column, and red means that warm water is in the upper 125-150m). If she doesn't go over the yellow or red areas, there is a chance she will not intensify as much as they think and if she goes over those very small blue patches, then she will definitely not intensify as much. 

So... in short, the intensity crucially depends on the path she actually takes. 

As I thought yesterday, again at the moment it looks to me as though her center of circulation from the satellite imagery is a little to the east/north of the center in the Cone of Uncertainty, which means she may be weaker because of that low level drier air, but also because she's actually currently moving along the edge of the area where the warm water is shallow (the green part of the map above). We will know the location of the center more accurately when the planes return the latest data, but the models are still taking this storm to the Louisiana region and they have been quite steady on that track. 

I do agree with the NHC that she is a hurricane at the moment because there is strong circulation in all levels of the troposphere, including the upper levels - a sure sign of a hurricane. And I also agree that she's a weak cat 1 because there isn't any clear eye (which starts to appear around 90 mph or higher). 

For those of you in the Cone of Uncertainty, I hope you are ready! Above everything, please heed the advice of your local emergency managers - they have the most up-to-date information on what is happening in your area. Also, a general note to remember to "run from the water, hide from the wind". This means that if you are in a flood zone, then definitely move to higher ground because most fatalities in hurricanes are related to water rather than wind. If you are in an area that is not prone to flooding, find a place away from windows and hunker down. However, if it was a cat 4 or higher and it was me, I would evacuate if I could. 

Atlantic Blob and Blobette

There are still two more areas to watch in the Atlantic: 

You can see them both in the satellite image above. The most likely to become TS Julian is the one to the south - due east of the Lesser Antilles. He has recently gained a lot of convection - he was inhibited by dry air until now. His circulation is fairly good in the lower half of the troposphere, so I think he may already be a Tropical Storm.

The second Blobette is north of the potential-future-Julian and east of Bermuda. She does not have as much convection (mostly cloudy) - again because of dry air. Her circulation is not as robust either, so we have a little more time. If she continues to develop, she will be future Kate. 

That's it for today, but tomorrow I'll be following with great attention the track that Ida takes.  And it's the weekend so there may be more than one update per day! 

Wishing all my northern Gulf readers well in their preparations! 

Toodle pip ,

J. 

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DISCLAIMER:

These remarks are just what I think/see regarding tropical storms - not the opinion of any organization I represent. If you are making an evacuation decision, please heed your local emergency management and the National Hurricane Center's official forecast and local weather service announcements. This is not an official forecast. If I "run away, run away" (Monty Python), I'll let you know.

Tropical Storm Ida: 26 August, Update A

And here's Ida! It was a busy Thursday (still practicing at trying to get the hang of those!... and Wednesday is the new Thursday, so it's like two Thursdays in a row!) so I'll jump into the fray. 

Ida is now in the Caribbean, but she was one of three tropical depressions in the Atlantic (the other two are still out there by the way - the circulation for both suggest that they are close to Tropical Storms, but not quite there yet). She was upgraded to Tropical Storm status just a few hours ago and currently has winds estimated to be around 40mph, central pressure 1006mb, which means she is a very weak Tropical Storm at the moment. Although, she does have a lot of rainy and thundery weather: 

For such a weak storm, she is quite large in her coverage - from the northern Caribbean to the south, and along the entire length of Cuba. However, structurally she isn't very well developed at the moment. The water under her is warmer than 29 deg C at the surface and the upper 150m of the water column under her is warmer than 26 deg C. This would help her to intensify, but there is quite a bit of wind shear so her lower level circulation is a little west of the circulation at higher altitudes - and the heavy convection is to the eastern side of the storm. She is already interacting with Cuba (a toot) and dumping a bunch of raindrops over that island.

She is in the Caribbean at 18.6N, 80.5W, heading NW at 12mph:

The track takes her over the tip of Cuba tomorrow. Now, looking at the satellite imagery and the location of this storm on the map, I am not quite convinced that the center is where they think it is - this is the sign of a weak storm... it is a bit tricky finding a center. To me, it looks like she's a little more to the north and a smidge to the east compared to the track map, but they will be sending in a plane tomorrow to get better data. If she is a little north/east, that track may shift to the east but it will also change her intensity and she may not be as strong at landfall as the NHC think (currently, they think she will be a borderline cat 2/cat 3 storm at landfall).

Although all the models are currently saying a Louisiana landfall, I'd say that the entire northern Gulf from the western edge of that Cone of Uncertainty and east to Appalachicola should get ready just in case (you don't want to run out of ice cream!), and we'll see if they have a better fix on the location tomorrow. 

I'm off to visit the Sandman now, but tune in tomorrow for the next installment. 

Ciao for now!
J.

--------------------------------------

DISCLAIMER:

These remarks are just what I think/see regarding tropical storms - not the opinion of any organization I represent. If you are making an evacuation decision, please heed your local emergency management and the National Hurricane Center's official forecast and local weather service announcements. This is not an official forecast. If I "run away, run away" (Monty Python), I'll let you know.

Tropical Storm Henri: 22 August, Update A

Ah, it's a Sunday. Ah, it's a Sundae. ;-) 

Tropical Storm Henri was finally downgraded from a cat 1 Hurricane to Tropical Storm status this morning at 7am EDT. Despite the additional convection and structure I noted yesterday evening, he just wasn't a Hurricane and never intensified into one. He made landfall at around 12.30pm this afternoon near Westerly, Rhode Island and about 15miles NNE of Montauk Point on Long Island. At the time of landfall, winds were 60mph, central pressure was 989 mb, which makes him a mid-size TS (TS range: 39-73mph).  

He has very little rain left now as he is inland over Connecticut (about 20 SE of Hartford) at 41.6N, 72.4W. He is heading WNW at 7mph and is really barely a Tropical Storm with winds of 40mph, central pressure 997mb:

The forecast track still calls for a sharp(ish) turn to the east as it has for a couple of days now, but that, I think will change and/or shift northwards - unless he starts moving eastward in the next few hours. 

Overall, at least in Boston and near NYC, I heard it was a non-event. 

This is my last update on Hooray Henri. The next storm in the Atlantic basin will be Ida. 

And for those of you who are wondering what happened to Grace... she has emerged into the Pacific and her circulation looks strong. I think they will name her/him in the next few hours as TS Marty. 

Enjoy the rest of the weekend!

Ciao for now,

J. 

--------------------------------------

DISCLAIMER:

These remarks are just what I think/see regarding tropical storms - not the opinion of any organization I represent. If you are making an evacuation decision, please heed your local emergency management and the National Hurricane Center's official forecast and local weather service announcements. This is not an official forecast. If I "run away, run away" (Monty Python), I'll let you know.

Hurricane Henri: 21 August, Update B

A quick update Regarding Henri... 

He is officially at around 38.6N, 71W, heading N at a fast 21 mph. Although he was in the Cone of Uncertainty he stayed on the eastern side and so the track forecast did, indeed, shift to the east: 

He may shift east a little more - the range of the cone at landfall is quite broad still. They are expecting him to take a NNW turn soon, but I don't see it quite yet. 

Officially he is still a very weak cat 1 hurricane with winds of 75mph, central pressure of 987mb (cat 1 range: 74-95mph). I still think he's weaker - a strong Tropical Storm. The wind shear is so clearly evident in the satellite imagery, although it is starting to decrease a bit now: 

He gained a little more convective structure but that is because he is still going over the Gulf Stream (warm - and deep warm - water) and the wind shear is decreasing a little. There is still a lot of dry air being pulled into this storm, which we can see from the lower level water vapour satellite imagery:

From this image, he does look like a bit of a mess.

However, he still has about 20 hours until landfall, so he could get a little stronger. I still think he'll be a very weak cat 1 storm or strong TS at landfall, and I think the NHC are thinking along the same lines as they have downgraded his longer term intensity forecast to be an 80mph storm at landfall.

As he approaches, please heed your local emergency managers because they have the best information. 

More tomorrow! Be good out there! 

Ciao for now,

J.

--------------------------------------

DISCLAIMER:

These remarks are just what I think/see regarding tropical storms - not the opinion of any organization I represent. If you are making an evacuation decision, please heed your local emergency management and the National Hurricane Center's official forecast and local weather service announcements. This is not an official forecast. If I "run away, run away" (Monty Python), I'll let you know.

Hurricane Henri: 21 August, Update A

A quick note to wrap up Grace and then on to the main story for today, Henri.

Grace made landfall in Mexico just before 1am local time near Tecolutla, Mexico, as a cat 3 storm with winds of 125mph, central pressure 962mb (cat 3 range: 111-129mph). She is now crossing Mexico and has weakened quite considerably - winds are 25mph, so she is not even a Tropical Storm. Her circulation is, however, intact enough that she may re-form in the Pacific. This is my last note on Grace. 

In the Atlantic, Hurricane Henri was upgraded to a cat 1 storm this morning. He is currently at 36.3N, 71.4W heading NNE at the very rapid 18mph, as expected. He is on track to make landfall in the Long Island/Connecticut/Rhode Island part of the world tomorrow:

I would still keep an eye on the Cone of Uncertainty because he could shift within that (to the east seems possible), but at 24 hours away from landfall, the NHC generally do a reasonably decent job with the track and I see no reason why this would change. 

It is still daytime, so this is what he looks like in the satellite imagery by day:

He looks like quite a beast but in a tale as old as time, he's not that ferocious. He is officially barely a cat 1 storm with winds of 75mph, central pressure 991mb (cat 1 range: 74-95mph). The intensity is a bit of an overestimate in my opinion. There is still a tremendous amount of wind shear with the clouds streaming off to the south and to the northwest. The NHC think that the wind shear will die down soon, but I am currently not seeing that happening enough to stop those clouds from streaming away. Peeling back what is visible in the satellite imagery above to see what his convection looks like shows us that a lot of those clouds are just clouds or nice rainy weather, and not as much of the heavy rain or thunderstorms we saw yesterday:   

It looks like has run into some lovely dry air again at the lower levels of the atmosphere, which is why the convection took a bit of a nose-dive and has weakened him further. To show you, here is the water vapour at the higher altitudes:

From the top, he looks like he has enough water vapour to keep going, but you can see that dark purple streak coming in from the west - that's dry air and it's at a lower altitude. To confirm that, here's the water vapour from a slice lower down in the atmosphere:

Here we see that not only is there dry air (yellow) on the west, but there is also some to the north as well (yellow/purple). 

He may regain some of that rainy weather and convection, but soon he will cross the Gulf Stream (warm water) and start to move over cooler waters which will make it a little more difficult for him. 

That's it for now, but as it's a Saturday I think you may get another update from me in a few hours. With wine.

For those in the path, be good and be ready, just in case. I hope you have your ice cream supplies... I mean hurricane supplies!

Ciao for now,

J. 

ps... New York? Today: Hurricane preparations and a 'We Love NYC' concert in Central Park? You crazy kids! 

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DISCLAIMER:

These remarks are just what I think/see regarding tropical storms - not the opinion of any organization I represent. If you are making an evacuation decision, please heed your local emergency management and the National Hurricane Center's official forecast and local weather service announcements. This is not an official forecast. If I "run away, run away" (Monty Python), I'll let you know.

Hurricane Grace and Tropical Storm Henri: 20 August, Update A

But of course, a few people didn't have quite that sort of Friday as they got ready for a storm or two! 

Hurricane Grace

Hmm... she fell off the bandwagon. She was behaving so well, but although she's on the right track, her intensity decided to make a run for it. She's at 20.7N, 96.3W, heading W at 10mph. She is close to landfall now and will be making landfall south of Tuxpan, Mexico very soon:

That's pretty much on target... with a note that she may actually cross Mexico, despite the mountains, and enter the Pacific to reform into a new Tropical Storm. This is not the first time a storm has done this, by the way and she will become a he... as TS Marty. 

But she intensified more than expected - in the last few hours she underwent rapid intensification (which is an area of very active research). We knew she was going to get stronger because the water is very warm, but she intensified more than expected and is now a major cat 3 hurricane with winds of 120mph, central pressure 967mb (cat 3 range: 111-129mph). She is already getting a little weaker as she is interacting with land:

She is already dumping a lot of rain (accompanied by thunderstorms to Mexico), and she will most likely be a strong cat 2 or weak cat 3 at landfall. 

Tropical Storm Henri

Now, for the storm I've had the most queries on today. I hadn't realized how many people I knew in the northeast! He is at 32.3N, 73.5W, heading N at 9mph, and as forecast, he made that northward turn:

He has also started to move a little faster will pick up speed even more as he moves between the high pressure to the east and low pressure to the west.

Henri is still officially a Tropical Storm trying to get past that wind shear, but he is a strong one with 70mph winds, central pressure 994mb (TS range: 39-73mph). As we saw yesterday, his convection shows a lot of very heavy rain and some thundery weather (red and dark red):

As I said, he is still under some strong wind shear, which we can see as the clouds are streaming to the south. I agree with the NHC on the current intensity - he is almost a cat 1 storm but not quite there yet. The clues are in the vorticity (circulation) maps which show the wind shear in his structure, but also show some circulation now in the upper levels of the troposphere (a sign that he is a hurricane). The lowest level map at 850mb: 

And in the mid-levels of the troposphere (500mb): 

As we saw yesterday, the circulation in the mid-levels doesn't align with the lower levels. However, unlike yesterday, there is now a signal of vorticity in the upper level of the troposphere (200mb):

It's that green dot to the southwest of the symbol that is Henri - again, it is shifted to the southwest compared to the mid-levels, so there is a lot of wind shear in the higher levels of the troposphere as well which is inhibiting his development. Until that wind shear gets weaker, he will not get very strong.  He will pick up speed and move over the warmest waters fairly quickly so as he approaches land, he won't have warm water to draw from by Sunday. I think, at the most, he will be in the cat 1 range but may even be a strong TS.  

Also, remember to keep an eye on that entire Cone of Uncertainty - I think he will shift a little more.

Good luck in the preparations! I'll be back tomorrow, including some daytime satellite imagery. 

Toodle pip,

J. 

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DISCLAIMER:

These remarks are just what I think/see regarding tropical storms - not the opinion of any organization I represent. If you are making an evacuation decision, please heed your local emergency management and the National Hurricane Center's official forecast and local weather service announcements. This is not an official forecast. If I "run away, run away" (Monty Python), I'll let you know.