WxWatcher007

000 WTNT43 KNHC 021445 TCDAT3 Tropical Depression Thirteen Discussion Number 1 NWS National Hurricane Center Miami FL AL132024 200 PM CVT Wed Oct 02 2024 The system we have been monitoring several hundred miles to the southwest of the southernmost Cabo Verde Islands has become gradually better organized this morning with some curved bands organizing to the west of the estimated center. Visible satellite images show that at least a broad closed circulation has developed. Based on the latest subjective Dvorak fixes of T2.5/35-kt from TAFB and T1.5/25-kt from SAB, advisories are being initiated on Tropical Depression Thirteen, with an initial intensity in between these estimates at 30 kt. The depressions initial motion appears to be slowly due west, at 270/6 kt. Over the next day or two this motion should continue, though some of the track guidance actually shows a south of due west motion, partially related to the steering flow and also the possibility that the center might try to reform underneath deep convective bursts in the southern semicircle. After 48 h, the guidance shows TD13 turning west-northwestward and then northwestward by the end of the forecast as mid-level ridging becomes more eroded on its northwestern side while a large long-wave trough becomes established over the Northwest Atlantic. The initial NHC track forecast has opted to favor a track close to the consensus aid TVCN. Interestingly, both the GFS and ECMWF are on the east side of the guidance, while HCCA is on the western side by the end of the forecast period. Intensity wise, initial strengthening could be on the slower end, as the system has to deal with some northwesterly shear related of the outflow from the much larger Hurricane Kirk impinging upon the system. However, the guidance insists this shear will soon decrease, especially after 24-36 h where the upper-level flow seems to split off into a cutoff low to the southwest, and a upper-level trough that shifts east of the depression, leaving the depression in a more favorable upper-level diffluent pattern. After TD13's inner core become better defined, the rate of intensification could increase after 36 h, and the latest NHC intensity forecast forecasts the depression to become a hurricane in 3 days. Additional intensification is forecast after that point as long as the cyclone tracks far enough away from the cold ocean wake left behind by Kirk. This forecast is roughly in the mean of the intensity guidance envelope. FORECAST POSITIONS AND MAX WINDS INIT 02/1500Z 10.6N 29.1W 30 KT 35 MPH 12H 03/0000Z 10.5N 29.8W 35 KT 40 MPH 24H 03/1200Z 10.2N 30.8W 40 KT 45 MPH 36H 04/0000Z 10.2N 31.9W 45 KT 50 MPH 48H 04/1200Z 10.4N 33.3W 55 KT 65 MPH 60H 05/0000Z 11.0N 34.6W 60 KT 70 MPH 72H 05/1200Z 11.7N 35.8W 65 KT 75 MPH 96H 06/1200Z 13.5N 38.1W 75 KT 85 MPH 120H 07/1200Z 16.5N 41.0W 80 KT 90 MPH $$ Forecaster Papin

Peak Season Forecast (Aug 20-Oct 20) Named Storms: 15 (6) Hurricanes: 10 (4) Major Hurricanes: 5 (1) Francine (H), Gordon, Helene (MH), Isaac (H), Joyce, Kirk (H)

Euro has explosive intensification over the next few days. Everything continues to point to another MH going on the board soon.

Just reposting so folks can see. Paging @CoastalWx

I smiled when I saw the new avatar this morning.

It really does look like a delayed peak, and maybe one that’s higher end with CV season heating up? Although weaker, the genesis signal in the Gulf still looks pretty robust. Definitely worth watching. I’m still way off my peak season forecast but some of each category will be added to the board soon. Peak Season Forecast (Aug 20-Oct 20) Named Storms: 15 (6) Hurricanes: 10 (3) Major Hurricanes: 5 (1) Francine (H), Gordon, Helene (MH), Isaac (H), Joyce, Kirk

I think two of the other challenges are that 1) we’re seeing events that are outside of our frame of reference. How do you adequately communicate the worst case scenario when a region has literally seen anything close into it? Worst on record doesn’t cut it when the impacts are almost biblical or an order of magnitude worse than the worst. 2) I think media/NHC really need to reconsider how TCs and impacts get categorized. I think the NHC has done tremendous work over the years talking more about hydro impacts, but categorizing TCs based strictly on winds seems increasingly inadequate given what we’re seeing even with non-hurricanes. Much of the media is still too focused on wind and coastal impacts imo. Not all to be sure, but many.

What a monster Camille was. Completed an ERC just offshore and quickly reintensified to 175mph/900mb. Just unreal. All of our 5’s rapidly intensified within 3 days of landfall. It’s about timing and “luck” as much as anything else.

If we’re just talking landfall zone, I think that’s true, but storms don’t end there of course. The surge of this one was record breaking and far reaching too.

Worse. This will be the storm of record for a lot of people.

Made my week. I’m so happy to hear this. Prayers for everyone waiting to hear from their loved ones.

Tropical Storm Kirk Discussion Number 4 NWS National Hurricane Center Miami FL AL122024 1100 AM AST Mon Sep 30 2024 Satellite images show an expanding area of central convection near the system with the low-level center on the western side of the deep convection. Microwave data from a few hours ago showed that an inner core is forming, with a partial eyewall noted on an AMSU pass. The initial wind speed is set to 45 kt based on 40-45 kt winds from a pair of recent scatterometer passes. The motion of Kirk appears to be westward at about 10 kt, with the center apparently re-forming to the south within the deeper convection. The track forecast is relatively straightforward, with Kirk expected to follow the south and southwestern edge of the subtropical high over the east-central Atlantic, resulting in a path that gradually gains latitude and Kirk moving northward by this weekend. Other than a small westward adjustment based on the initial motion, the new forecast is very close to the old one. The environment around Kirk appears quite favorable for strengthening during the next several days, with warm waters, a moist environment and low shear in forecast. Given the formation of an inner core, the rate of strengthening has been raised in the short term, and rapid intensification is a distinct possibility. The biggest negative to this system is probably its large size, which could eventually promote eyewall replacement cycles and some SST cooling ahead of the system. Still, almost all of the guidance show Kirk becoming quite a large and powerful hurricane. The new NHC intensity forecast lies between the dynamical model consensus and the statistical-dynamical models, which are quite bullish on this system. FORECAST POSITIONS AND MAX WINDS INIT 30/1500Z 13.5N 34.8W 45 KT 50 MPH 12H 01/0000Z 13.6N 36.4W 55 KT 65 MPH 24H 01/1200Z 14.0N 38.7W 70 KT 80 MPH 36H 02/0000Z 14.7N 40.4W 80 KT 90 MPH 48H 02/1200Z 15.8N 41.8W 90 KT 105 MPH 60H 03/0000Z 17.1N 43.1W 100 KT 115 MPH 72H 03/1200Z 18.4N 44.4W 105 KT 120 MPH 96H 04/1200Z 20.7N 46.7W 110 KT 125 MPH 120H 05/1200Z 23.5N 48.7W 105 KT 120 MPH $$ Forecaster Blake

Peak Season Forecast (Aug 20-Oct 20) Named Storms: 15 (6) Hurricanes: 10 (3) Major Hurricanes: 5 (1) Francine (H), Gordon, Helene (MH), Isaac (H), Joyce, Kirk

Worth a thread given the forecast to become a major hurricane. Not expected to impact land but could be a big ACE producer. 000 WTNT42 KNHC 292045 TCDAT2 Tropical Depression Twelve Discussion Number 1 NWS National Hurricane Center Miami FL AL122024 500 PM AST Sun Sep 29 2024 The system we have been monitoring in the eastern Tropical Atlantic (AL90) has continued to become better organized throughout the day. After an overnight deep convective burst, outer convective banding has become better defined, noted by the most recent TAFB subjective Dvorak fix of T2.0/30 kt. GOES-16 1-minute visible imagery also shows that the circulation, which was more elongated this morning, has become better defined on the western side, suggesting a well-defined closed vortex now exists. Based on the above data, advisories are initiated on Tropical Depression Twelve this afternoon, with an initial intensity of 30 kt. The motion of the new depression currently appears to be westward at 270/8 kt. A prominent subtropical ridge to the north should continue to steer the system generally westward to west-northwestward over the next couple of days. After that time, this ridge becomes more eroded by a mid-latitude trough on its western side, resulting in the system gradually turning more poleward through the end of the forecast. In general the guidance is pretty tightly clustered for the first 48-60 h, with spread increasing a little more thereafter related to how quickly the system turns poleward. The initial NHC track forecast lies near the HFIP Corrected Consensus Approach (HCCA), which favors the ECMWF track a little further west than the GFS track. For at least the next 2-3 days, vertical wind shear is expected to remain low, mid-level moisture stays high, as the system remains over 29-30 C sea-surface temperatures. Yet, the current large convective envelope of the system suggests it may take a day or so for an inner-core to become established. Thus, the initial rate of intensification is a bit slow, a little under the guidance for the next 24 hours, but then becomes faster and ends up near the IVCN consensus aid by 120 h. The initial NHC intensity forecast shows TD12 becoming a hurricane in 60 h and a major hurricane in 5 days. FORECAST POSITIONS AND MAX WINDS INIT 29/2100Z 13.8N 32.5W 30 KT 35 MPH 12H 30/0600Z 13.9N 33.6W 35 KT 40 MPH 24H 30/1800Z 14.2N 35.7W 40 KT 45 MPH 36H 01/0600Z 14.5N 38.1W 50 KT 60 MPH 48H 01/1800Z 15.0N 40.0W 60 KT 70 MPH 60H 02/0600Z 15.9N 41.5W 70 KT 80 MPH 72H 02/1800Z 17.4N 42.7W 85 KT 100 MPH 96H 03/1800Z 20.0N 45.0W 95 KT 110 MPH 120H 04/1800Z 22.5N 47.5W 105 KT 120 MPH $$ Forecaster Papin

Some of the analysis is truly remarkable

Oops, I posted in the wrong thread. Agree though that any CVs are highly unlikely to be impactful here.

Exceptionally late start to CV season, but it looks like it’s underway.

There’s a strong signal that CV season was delayed but not quite denied. 90L and/or the wave behind it could become quite strong.

You and your family are in my thoughts and prayers. I hope he’s ok.

Totally agree. More would’ve tested the coast and the area to my SE if the area had a better road network (and it was daylight). And yeah, while it was a good eyewall I also thought given the velocities aloft the winds would’ve been much more intense. I know you’re not downplaying anything. That’s a legitimate concern. Edit: if I had to guess I would say we peaked between 100-120. I know the floor was verified with the airport report, and I think based on some of the damage I saw compared to Idalia the year before that there were isolated pockets closer to 120 gusts. I think that’s in line with what others saw—high end 2/low end 3 gusts. With a similar radar velocity profile Laura was much worse.

It looks like both the latest iterations of the GFS and Euro want to bring its remnants or whatever up here after the Gulf, but, ya know, . The first and only time I’ll ever use that emoji.

Appreciate the kind words. Would love some thoughts from others too but looking back at least at the Perry airport data it does seem like there were more gusts than high end sustained winds. Part of that may be related to what recon was finding pre-landfall. There were a lot of tremendous flight level winds but not a lot of surface estimates that matched up—but note that the NHC is reviewing its SFMR process. It’s possible that in the hours it took for Helene to close off its inner core and expand its hurricane force wind field Thursday that there just wasn’t enough time to effectively translate those very high winds aloft to the surface. Each hurricane has its own sound, but there wasn’t much of a howl in the eyewall. It was definitely more big gust dependent. Funny enough, looking southeast there was tremendous lightning and a big roar just off the deck, but the southern eyewall was nonexistent when we got to the other side of the eye. As for the gusts further inland, they were definitely aided by two things and maybe aided by another. All created the perfect conditions for a generational inland wind event. 1) This was a fast mover. It reminded me of NE systems that rocket north and bring wind far into the region. The 1938 Hurricane was a classic example. It didn’t decay quickly by crawling inland. 2) The trough/jet assisted in maintaining Helene’s intensity without a doubt. See Windspeed’s earlier post about a possible sting jet. Even without that, the jet enhanced winds aloft as Helene was moving quickly but decaying—keeping high end gusts on the table. 3) This is somewhat educated speculation, but I think the big winds aloft at landfall allowed for the storm to keep producing big gusts inland. Kind of related to #1 but if Helene isn’t intensifying at landfall and producing big wind just off the deck there’s no way the gusts we saw could propagate as far inland as it did.