Windspeed

Your only criteria for an "active MDR" only ever appears to be when we have a major hurricane in progress, and your posts are uncoincidentally absent. Only the 2021 season lacked a classifed TC in the MDR that failed to become a hurricane. 2023 saw four, one becoming a Category 5 while still in the MDR. The MDR is not going to produce long-tracking major hurricanes every season. Yes, we all know this. I'm not even sure why I bothered a response. Perhaps for everyone else who doesn't know your history and might become misinformed.

LOL, nice try. We had a Category 5 hurricane in the MDR last year. We've already had a Category 5 hurricane that developed out of the MDR this year.

WAM intensified and gained significant latitude in late July. The Sub-Saharan region, even portions of the Sahara have seen significant precipitation the past month. But if you recall, the ITCZ was at a low latitude and very active in June before WAM intensified. We have seen record downpours from the Arabian Peninsula to Morocco over the past month. Additionally, we've seen enhanced SAL plumes due to SPH placement across the central Atlantic. You may also recall that the AEWs that became Debby and Ernesto did not become convectively dominate until they reached the WATL. Both systems were choked of stable airmass. They eventually did moderate and develop, but only after mixing out SAL.

Mike, where have you been? Lol... There's been plenty of discussion about the West African Monsoon and latitudinal placement. AEWs do not, or at least rarely, develop north of the CVs when they exit there. That being said, the WAM is losing steam, and it is modeled to do so. ITCZ placement should drop in latitude by September, and the SPH will shift into a more climatogical steering flow for MDR TCs. I actually think it is somewhat amusing that TC enthusiasts and pro tropical climatologists are all scrambling due to the approaching peak with limited model support. This is mostly due to varying ranges of significantly high named storms numbers. I think forecasting 25+ named storms is a huge risk to take in any year no matter the long-range ECMWF+UKMET superblends, climo patterns, or AMO or ENSO states. Too many caveats and anomolies can occur when all things look extreme. WAM placement and East Atlantic Nino being a perfect example this year. I should stress, however, that WAM will weaken, even if it is abnormally strong. You want some monsoonal enhancement to favor AEWs with a low-latitude ITCZ if you want MDR TCs. We're still going to get that the bulk of September. Sure, NS numbers may not hit all these crazy forecasts, but we will get active, and we will see intense TCs out of the MDR during that stretch. Back to the present, though the wave south of the CV looks good, modeling support is pretty limited. However, it doesn't look too bad right now, and bears watching. As it moves into the western MDR this coming week, the MJO may time just right to enhance development. Even if limited, some EPS support is there, and that could increase as we get into midweek.

Hone has clearly organized further overnight and now has a clearing eye with multiple CBs rotating around it. Radar is also telling. The hurricane appears to have intensified. It will be interesting to see how the flow over the Big Island affects and influences Hone's structure. The Lee side of Mauna Loa and Mauna Kea's massifs will most likely have some type of deformation on the core as the hurricane positions SW of the island. In fact, that may already be occurring as the eyewall appears pinched in the NW quadrant. Also, keep in mind that the radar beam is blocked to the SW to N due to Mauna Loa.

NE quadrant was weaker than the previous NW pass. Interestingly, the NW quadrant of the eyewall had the most intense echoes. Not sure if this will be enough for any upgrade. Again, it's borderline. We'll see if they do a south to N for their final pass.

If officially upgraded, it will be, yes. With the current radar presentation and in situ recon data, CPHC may issue a special advisory, though they may wait on the NE pass to the reconfirm before releasing it. Edit: Latest VDM:

64 kt SFMR in the NW quadrant. Hone is probably a minimal hurricane now. We'll see what the next pass through the NE quadrant shows.

Improvement in structure on IR and radar due to persistent convective bursting that has occurred since the last recon mission. We'll see if this translates to any deepening via the recon mission currently in progress. Should have a new VDM within the hour.

So far, so good. Hone has failed to intensify further. Environmental conditons are managing to keep the TC in check.

Shanshan's mid-level vortex is being stretched due to close proximity to the mid-to-upper cutoff, which is now an intensifying ULL. The ULL has been evolving while imparting substantial shear across the TC the past few days. Interestingly, though shear has a negative impact in preventing Shanshan's core from developing a stable eyewall, strong diffluence (spreading wind vectors) around the ULL has already been aiding in strong convective bursting to keep the low-level vortex vigorously organized, and it is exactly this phenomenon that favors future rapid intensification. As the ULL retrogrades to the WSW and gains separation from Shanshan, it will flip from unfavorable to exceptionally favorable in mid-to-upper flow. The 400-200 hPa jet pivots away to create a mass sink to evacuate air. Diffluence remains, but you now have divergence aloft with poleward and westward channels. Simultaneously, Shanshan moves over relatively untouched SSTs with deep heat potential. So we're all looking at this thing with apprehension because, based on the evolving and modeled steering layer, this TC has the potential to be the most powerful typhoon to make landfall in Japan in decades. I am not saying it will. But you may still be dismissive of the high-end modeling (which is probably overdoing it) and are certainly justified to worry of an intense and destructive landfall.

Little change in intensity is expected in the next 12 to 18 hours, followed intensification Saturday and Sunday. Easterly winds aloft, which have inhibited outflow in all but the south and southwest quadrants, will relax tonight and Saturday as a weakness develops in the upper level ridge north of the cyclone. Sea surface temperatures will remain around 26-27C, which will be sufficient for intensification, possibly to hurricane strength, later in the weekend. By Monday, westerly vertical wind shear increases sharply, and some drier mid-level air appears to begin entraining into the system. This should result in steady weakening. The intensity forecast was changed little from the prior package and lies near the IVCN between the stronger dynamical guidance and the weaker statistical guidance. Easterly mid-to-upper flow has kept the core of the Hone rather devoid of convection today. The CPHC is forecasting that flow to relax on Saturday, which should allow convection to rebuild around the core. At any rate, this is the reasoning behind Hone's delay in intensification, and it isn't forecast to approach hurricane strength until positioned south of the island chain, having already bypassed the Big Island. In the last few hours, a new burst of convection is trying to wrap upshear.

The disturbance that may threaten Hawaii would be approaching from a direction that typically is not conducive for strong hurricanes. However, currently, SSTs are marginally supportive SE of Hawaiʻi Island (the Big Island) if our hypothetical TC can get going and establish an inner core. The shallow 26-27°C layer might provide just enough thermal support for a minimal hurricane that maintains a steady rate of motion. A compact structure may also aid in intensity. Hopefully, any potential TC, regardless of TS or minimal 'cane, would remain far enough south to lessen impacts, perhaps only to provide some beneficial rains.

One of the larger WAM-anchored disturbances that I can recall in recent years will be moving off of WA. It will be interesting to see how modeling picks up on this feature late week. Does the low-latitude portion of the surface trough axis persist or the northern low that appears to be waning in convection?

Not every hurricane is going to rapidly intensify. In fact, most do not. We've just had so many hurricanes to go through RI over the past three decades during ASO that we've come to expect it to occur when TC/SHIPs modeling sniff out any potential. This year, so far, our three hurricanes all originated from tropical waves/disturbances that traversed the MDR during the portion of the season that is climatologically less favorable. June into the first half of August is notorious for ~700 hPa jet and easterly SAL expulsions that cross the sub-tropical Atlantic. I can not stress this enough. Sure, every two to three years, we get an early MDR TC form. But they most always fizzle out or become shredded by shear in the ECARIB graveyard. 2024 has been an anomaly like 2005 in that we have had multiple MDR waves already form into TCs and go on to become hurricanes. That doesn't mean they won't still struggle or have issues with plumes of stable airmass. Only Beryl was able to rapidly intensify because it formed at such a low latitude. Even though climatological deterrents were still in place (SAL and shear), it managed to be positioned just perfectly for those factors to be lessened. I can remember a time when you simply did not look at the MDR for threats before August. June and July hurricanes came from the tail-end of stalled frontal boundaries in the GOM, WATL surface troughs, or WCARIB CAG/disturbance systems. Generally, the WAM, SPH and wave placement is unfavorable until the last week of August. It's therefore no surprise that we usually see an abrupt ramp up in activity just a few weeks before early September peak. Once the pattern flips for the MDR during an active season, TCs begin developing with much higher frequency and under favorable atmospheric setups for a higher chance of rapid intensification to occur. Large waves due to temporary WAM placement will moderate/moisten the MDR, and then as the SPH shifts and WAM breaks down, ITCZ placement and tropical waves around 10-15°N latitude should have a more favorable MDR to traverse. SAL is never fully eliminated but significantly lessened. I will finish by mentioning the first time that I ever learned about SAL. The person discussing it was named John Hope. The tropical wave he was analyzing on TV was a very healthy one that eventually became a hurricane. Not just any hurricane, mind you, but Hugo. Yes, 1989, Hugo had dry air north of its circulation within its envelope. I can also recall, many years later, the early development of Isabel mixing out SAL in its rather large circulation. My point is that SAL is an environmental characteristic of the Atlantic Basin. When it's strong, it suppresses. When it is weak, it's just not as much a factor.

Ernesto is giving us a final grunt before moving over cooler SSTs. The satellite presentation, even if short-lived, is the best it has looked since its initial intensification north of the Antilles. As such, ADT numbers are spiking upwards. The current trend may not persist until the 11AM AST advisory package to see any official upgrade in category, but clearly, the hurricane has got its act together this morning. There's even lightning showing up in the eastern eyewall.

RE: Window for intensification. Ernesto is not in a bad environment as far as current shear and upper outflow, and it still has roughly 9-12 hours over heat content that would support further strengthening. My skepticism against more significant intensification, however, continues to be stable airmass emplaced around the circulation and core. If Ernesto's eyewall continues to gain enough convection and can shield off any intrusion or ingestion tonight, perhaps it may get officially classified Category 2 again prior to the core moving over the sub 26C° isotherm. But upper tropospheric temperatures aren't really cold enough to support deep convection once SSTs get down below that threshold. We have certainly seen plenty of examples in past years of TCs under a cold pool aloft in association with upper troughs where evaporation and lapse rates continue to support deep convection. I don't think that will be the case here. Ernesto should begin to fall apart once it passes north of 26°C.

Ernesto's structure has improved, and most remote sensing data supports the upgrade back to hurricane status. It does have some characteristics of a reformed core eye band, if intermediately broken. However, I don't think the recent convective bursting is strong enough for any substantial strengthening back to Category 2. Reintensification in line with some increase in ADT values is currently around 75 kts / 85 mph. If it were to continue bursting and wrapping up, sure, perhaps Category 2 is possible again tonight, though the window for this is closing.

The 2024 season has been incredibly efficient. The first five named storms have made landfall. I'm not sure I can ever recall that occurring in previous seasons since tracking as a kid.

000 WTNT45 KNHC 170857 TCDAT5 Hurricane Ernesto Discussion Number 23 NWS National Hurricane Center Miami FL AL052024 500 AM AST Sat Aug 17 2024 Satellite and surface observations indicate that the center of Ernesto made landfall on the western side of Bermuda at about 430 AM AST, with the National Museum of Bermuda recently reporting light winds and a central pressure of 972 mb. The system overall has become less organized as drier air has infiltrated much of the circulation's southern semicircle. Earlier aircraft reconnaissance data supported 75-80 kt as an initial intensity, and with the degradation in the satellite imagery, 75 kt is chosen as the current intensity (and operational landfall intensity). The Air Force Hurricane Hunters should be out again in a few hours to sample the cyclone. While the current moderate shear is forecast to weaken today, it will take some time for the vortex to recover from the dry air as it moves across warm waters north of Bermuda. Thus little change inintensity is anticipated in the short term, and re-strengthening could begin tomorrow. This should be a fairly short-lived window, however, since Ernesto will be crossing the north wall of the Gulf Stream on Monday while moving into a strong wind shear environment. Therefore, steady weakening is forecast for the work week, and Ernesto is expected to complete extratropical transition near or just east of Newfoundland. The NHC intensity forecast is largely an update of the previous one, a bit lower in the short-term to account for recent guidance. Ernesto has turned more to the north-northeast overnight and slowed down to about 8 kt. The motion should creep in that direction today as the hurricane is stuck in an area of lighter steering currents, waiting for the next trough to move off the U.S. East coast. This slow motion and Ernesto's large size will cause a long duration of impacts through tonight on Bermuda. The trough should force the cyclone to accelerate northeastward later in the weekend and early next week, taking Ernesto near Newfoundland Monday night. The guidance is again slower than the previous cycle, so the NHC track forecast is trended in that direction. Global model fields depict that Ernesto should open into a trough, or become absorbed in a larger polar low by 120 h over the northern Atlantic ocean, thus the NHC forecast now shows the system dissipated at that time. Key Messages: 1. Ernesto is expected to bring periods of strong winds, storm surge and battering waves on Bermuda through tonight. A hurricane warning is in effect for the island, and residents there should listen to orders from local officials. 2. Heavy rainfall from Ernesto will continue to impact Bermuda through tonight and will likely result in considerable life-threatening flash flooding, especially in low-lying areas on the island. 3. Even though Ernesto is forecast to remain well offshore the U.S. East Coast, swells generated by the hurricane are expected to affect the area through the weekend. Beach goers should be aware of a significant risk of life-threatening surf and rip currents, and stay out of the water if advised by lifeguards. Surf and rip currents are also possible on the Bahamas, Bermuda, and Atlantic Canada during the next few days. 4. Interests in Atlantic Canada should monitor the progress of Ernesto. FORECAST POSITIONS AND MAX WINDS INIT 17/0900Z 32.3N 64.8W 75 KT 85 MPH 12H 17/1800Z 33.3N 64.4W 70 KT 80 MPH 24H 18/0600Z 34.6N 63.9W 70 KT 80 MPH 36H 18/1800Z 36.6N 62.9W 75 KT 85 MPH 48H 19/0600Z 39.8N 61.2W 80 KT 90 MPH 60H 19/1800Z 43.5N 57.5W 70 KT 80 MPH 72H 20/0600Z 47.0N 51.5W 60 KT 70 MPH...POST-TROPICAL 96H 21/0600Z 51.5N 32.0W 40 KT 45 MPH...POST-TROP/EXTRATROP 120H 22/0600Z...DISSIPATED $$ Forecaster Blake

That's one hell of a hypothesis by Webb. Alarming, even:

As has been discussed thoroughly in the thread, Bermuda is built to handle strong hurricanes. But you are silly to downplay this as a non-story. 17k+ are now without power, and there will still be further grid and infrastructure damage. They will most likely have any old-growth tree damage that may've survived previous storms. Additionally, there will be some roof damage regardless of the quality of building/wall supports with 80-90+ gusts occurring. We'll need to be patient and see the aftermath and damage assessment in the coming days. It does look like the low-level vortex is going to make landfall.

This year has been more quality versus quantity so far. We're on the 'E' storm. Some of the more recent high number of named storm seasons also saw a lot of weaker TCs and ST systems that formed in the early months. This year we've only had two weak systems develop that did not become hurricanes. Even Chris probably would have become a BOC 'cane given more time over water. I suppose we may still see a plethora of central Atlantic systems form at higher latitudes during September and October besides the more potent southerly systems. But overall, I don't think this year would be remembered by busting on total number of named storms if indeed we do witness a significant number of intense hurricanes. Again, quality over quantity. 2017 was a horrible record season that did not hit 20 named storms. Only 17 formed that year, in fact.

To continue the above discussion, here's an excellent thread by Kaylan Patel on upcoming developments with regards to the WAM, the MDR, and pattern placement by September.

Agreed. Need I remind everyone that it is August 15th. Conditons are not yet prime. The proverbial switch generally flips by the last week of August (as per the climatological norm) for a more favorable MDR, regardless of whether the season is to finish as hyperactive or not. Yet, even though we've had easterly SAL plumes and periods of shear, we've had three hurricanes, two of those as landfalls (potentially three), with two reaching Cat 2. Beryl's early season rampage through the Caribbean may be an anomaly, but I'm fairly confident we'll be dealing with several big ACE producing CV long-trackers that will likely drive through the islands again unfortunately. One or two may become GOM threats. The ECONUS trough most likely will give way to re-extension of the SPH by September. To add, with near-record SSTs in place across the basin and the evolving La Niña, we may see a burst of late season activity as well. Certainly, October may be similar to September in pattern and continued late season MDR development we have seen in previous years. Obviously, the more typical WCARIB / CAG developments by November.