Windspeed

Yeah this is going to get interesting. I can see TD14 getting named first and may even pull off some faster intensification prior to landfall or interaction with the Yucatan. However, it may get sheared heavily in the GOM depending on interaction between upper trough and southerly flow on the western periphery of the large anti-cyclone positioned over the Bahamas in a few days. The exciting thing about this setup is the great amount of uncertainty even among the best tropical meteorologists. Everyone is in wait and see mode. TD13 may still reform a vortex and go bonkers if positioned just north of the GA. Then again it may do nothing and leave TD14 to go at it alone in the GOM. Then there is the public aspect of trying to make a forecast that creates awareness and yet leaves the possibility that one or both systems may not pan out.

Making a single thread to cover semi-related, off-topic and non-meteorological discussions for both Laura and Marco. Both systems are going to influence each other directly and indirectly and I am sure frequent postings will heat up enough to warrant it. Speaking of...

What the hell is going on with the GFS lately? Sheesh...

Race is on here for the L and M names. If recon finds a sufficient low-level vort with TS force and TD14 may win Laura. Interestingly recon also finds a pretty strong trough over the north-central GOM on its way there. Going to be fascinating watching all these dynamic features evolve with the tropical systems.

Watch the low level cloud field. They're starting to align west to east into the convection. Might be the beginnings of something closing off at the surface. Definitely keep watching that if convection can keep firing in the same location of the axis.

97L has been pulsing convection this morning. Again, it's a wait and see if that can remain persistent long enough to increase low level convergence and close off a low level vort. No signs yet based on visible. But the potential is still there as long as convection keeps firing. The disturbance does appear to be slowing down its westward motion.

There it is, Chief... Jokes aside, that is the most impressive sub-Saharan MCS I have seen since Irma. This is going to be fun to track regardless of pattern shenanigans. Granted, Florence's was nice too, but not that intense.

Genevieve still has a beautiful structure and warm eye, however, the core eyewall convection has seemingly reached a steady-state plateau and intensification has ceased. This is likely due to something I had forgotten to consider earlier. SSTs... Genevieve is traversing Elida's wake. Though immediate shallow layer SSTs are likely still 28°C, water below the 26° isotherm in the colder thermalcline has likely upwelled. This may not have even had time to show correctly on SST analysis as this area has been cloud covered. So there you go, Genevieve has peaked and will probably hold steady until tomorrow when weakening begins.

Remnants of Kyle and its energy is phasing with a low pressure system over the Northern Atlantic. Multiple strong systems will blast through the UK this week.

We've been in an unfavorable phase, but favorable upper 200 hPa vorticity is now spreading over the Atlantic Basin and should have a negative mean through the end of August. Afterwards, a rather neutral phase will persist over the western basin with stronger vorticity remaining over the far EATL/WAM. At any rate, you don't need a strong MJO, you just don't want to see a suppressive regime dominating the entire basin. Upper divergence should persist over the WAM through peak season to keep strong AEWs exiting the African continent.

There's nothing really standing out yet on visible at the surface, but the overall convective envelope continues to improve. There is still clearly cyclonic motion to the wave axis being encompassed by strong convection. Notable curved banding on the backside is developing. Subjectively speaking, something about this disturbance just has that look. We'll see if more rapid convective pulsing can spin up a vortex by tomorrow as the wave slows down in westward motion through the central deep Caribbean. It also probably would help if the northern periphery of the axis is where a low-level vort can develop as that would get it further away from any airmass influences of Venezuela landmass.

Mentioning this here as it relates to an overall pattern feature. The MJO is currently increasing favorability across the Atlantic Basin as was forecasted. This should remain in place for the next few weeks, perhaps longer. Interestingly, one of the side effects of robust upper 200 hPa vorticity can be a negative when associated with a monsoonal trough. That's exactly what we have going on in the EATL right now. The WAM extension west into the MDR with two competing wave axii and strong low-level convergence amplified by the ITCZ. This is otherwise generally great for TCG; however, if you have multiple regions of vorticity within close proximity and robust convection occurring over a large area, it can sometimes take an extended period of time for one of the competing regions of vorticity to become dominate. If these regions were further apart, you'd likely get two TCs develop. A favorable MJO phase is always better for TCG than a an unfavorable phase. But there can still be caveats. There has also been research done on how a positive MJO phase influences rapid intensification. Interestingly, it was determined that though the MJO greatly enhances convection to allow for TCG, it doesn't necessarily help with rapid intensification of a particular cyclone. Again, competing convection may have something to do with this as the internal convection within the TC's vortex structure may have to compete with surrounding areas of convection. Sometimes that can be a negative factor, though perhaps not as much if the vortex is already intense. We saw this occur with Major Hurricane Matthew in the deep Caribbean back in 2015. It became a Category 5 despite having to compete with backside intense MCS complexes with competing MLCs rotating outside its main vortex. Though there is a need for more research to be done, I suspect the best scenario for TCG would be an isolated wave convectively influenced by a favorable MJO phase, but not one so strong that it over-amplifies surrounding regions of convection, which may induce subsidence on the resulting TC. Obviously when dealing with a monsoonal trough with multiple wave axii, the possibility of slower tropical development may be a real thing. Though that tends to work itself out when one of the low-level vortices eventually becomes dominate. We'll see how this evolves with 98L. In the meantime, 97L may benefit from the phase much more favorably for TCG in the next 24-36 hrs, as it is certainly isolated, and will position itself in a region of the Caribbean for improved low-level convergence as low-level wind profiles becomes more favorable. Upper divergence isn't an issue. There is some dry air, but the overall upper pattern is favorable.

Genevieve now a Category 4. Maximum sustained winds have increased to near 130 mph (210 km/h) with higher gusts. Genevieve is a category 4 hurricane on the Saffir-Simpson Hurricane Wind Scale. Additional rapid strengthening is possible during the next 12 to 24 hours. Rapid weakening is forecast to begin by late Wednesday and should continue through the end of the week.

It may look like garbage overall but it's still a healthy wave. Convection keeps pulsing just enough along the wave axis. It's biggest problem has been steady and strong easterly level flow working against development. That is forecast to ease off by tomorrow and become more southeasterly, therefore, development potential remains as long as convection can keep up in the short-term.

Genevieve is now a major hurricane. Still forecast to peak as a Category 4 and still intensifying; perhaps not as rapidly as some of the guidance suggested, though still plenty swift to be in upper RI range. The system was classified just 44 hours ago. The chaotic nature of an eyewall core vortex evolving. It still has plenty of time to make a run at Category 5 as favorable conditions will persist 12-24 hrs and MPI could be reached by this evening. By Wednesday evening conditions will not be as supportive. Regardless of peak intensity, looking for Genevieve to ramp up deeper internal convection today.

Genevieve is trying to clearing out a persistent eye. Really well-developed hurricane now with impressive structure.

The GFS-Para is the experimental GFSv16 versus the current operational GFS model (GFSv15) that has been in operation since 2019. GFSv16 would potentially be the new operational GFS next year barring any upgrade setbacks. At any rate, this morning's run had a very interesting throwback track to Charley. Again, this is an experimental product and even if operational, would be out in the medium range if 97L were to develop. Still interesting nonetheless...

2PM EDT Outlook with respect to 97L: A tropical wave approaching the Windward Islands is producing a large area of disorganized shower and thunderstorm activity. This disturbance is moving westward at about 20 mph, and is expected to continue to move quickly westward over the eastern and central Caribbean Sea during the next couple of days, which is likely to limit significant development. After that time, however, the system is expected to move more slowly westward across the western Caribbean, where upper-level winds could become more conducive for the development of a tropical depression during the latter part of this week. Regardless of development, locally heavy rainfall and gusty winds are expected over portions of the Windward and southern Leeward Islands through Tuesday morning. * Formation chance through 48 hours...low...20 percent. * Formation chance through 5 days...medium...50 percent.

2PM EDT Outlook: ZCZC MIATWOAT ALL TTAA00 KNHC DDHHMM Tropical Weather Outlook NWS National Hurricane Center Miami FL 200 PM EDT Mon Aug 17 2020 For the North Atlantic...Caribbean Sea and the Gulf of Mexico: 1. A tropical wave approaching the Windward Islands is producing a large area of disorganized shower and thunderstorm activity. This disturbance is moving westward at about 20 mph, and is expected to continue to move quickly westward over the eastern and central Caribbean Sea during the next couple of days, which is likely to limit significant development. After that time, however, the system is expected to move more slowly westward across the western Caribbean, where upper-level winds could become more conducive for the development of a tropical depression during the latter part of this week. Regardless of development, locally heavy rainfall and gusty winds are expected over portions of the Windward and southern Leeward Islands through Tuesday morning. * Formation chance through 48 hours...low...20 percent. * Formation chance through 5 days...medium...50 percent. 2. A tropical wave over the eastern tropical Atlantic is forecast to interact with another disturbance located several hundred miles southwest of the Cabo Verde Islands within the next day or two. This interaction is expected to lead to the formation of a broad area of low pressure, and conditions are forecast to be conducive for the development of a tropical depression during the middle-to-latter part of this week while the system moves westward to west- northwestward at 15 to 20 mph across the central and western portions of the tropical Atlantic. * Formation chance through 48 hours...low...30 percent. * Formation chance through 5 days...high...70 percent. Forecaster Brown

You're going to come off as quite bipolar in your postings if you start hanging on each GFS operational run for long-range track and immediately making a declaration of death in your "outlook" of the upcoming period every time that track doesn't pan out. The very next run could have an entirely different TCG location and resulting stronger track intensity ~120 hrs out. Best to just realize we have potential development to follow. The ensembles are still more valuable in the long range as has already been stated multiple times, repeatedly. When we actually do have a TC to track, we then may start focusing more on operational track placement and pattern, though you still must be cautious beyond 144+ hrs for the downstream pattern, as that can easily flip. At any rate, your persistent declarations about the peak season being this or that based on single operational model outputs every six hours is not particularly contributive to the discussion. That's not to say we should not point out a pattern that swings more unfavorable. But that is entirely not what is being suggested by modeling here in the mid-to-long range.

Thought that was already deemed 98L. Sometimes they'll discuss them as ALxx. Former NHC Specialist Kimberlain referred to the disturbance as AL98 earlier. At any rate, unsurprisingly the GFS weaker in the mid-to-long range with the potential TC due to tracking through the Greater Antilles and timing/position being not as aligned with strong upper ridging. That upper ridging is a beast though and is probably more the takeaway; i.e., IF a TC gets positioned under that, things could escalate quickly.

425 WTPZ42 KNHC 171451 TCDEP2 Hurricane Genevieve Discussion Number 5 NWS National Hurricane Center Miami FL EP122020 1000 AM CDT Mon Aug 17 2020 Data from a recent SSMIS microwave overpass reveals that an eye is trying to form underneath the deep convection of Genevieve, but there is some dry air near the center that may be disrupting the formation of a solid eyewall. Despite that dry air, large bands continue to the southwest and northwest of the center, and the deep convection over the center is expanding in size. The latest Dvorak satellite intensity estimates from both TAFB and SAB support raising the initial intensity to 65 kt, making Genevieve the third hurricane of the 2020 Eastern Pacific hurricane season. Genevieve jogged a little northwest over the past few hours, but the longer term motion has been west-northwest at 16 kt. The main steering mechanism for the cyclone is a strong mid-level ridge which extends from the southwestern United States southeastward into Mexico. The model guidance varies slightly on the strength and orientation of this ridge over the next few days, which could play a role in how close Genevieve gets to the southern portion of the Baja California Peninsula. The GFS is the farthest east, but still keeps the center well offshore, while The UKMET is the westernmost solution. Overall, the guidance has changed little since early this morning, and the official forecast is very near the previous track, which lies near the TVCX/TVCE consensus. The small amount of dry air near the center should get worked out of the circulation shortly, and there is high confidence that the rapid intensification of Genevieve will continue for the next 24-36 h. The SHIPS Rapid Intensification Index (RII) shows a greater than 95 percent chance of a 30 kt increase in strength in the next 24 h, and nearly an 80 percent chance of a 45 kt increase in the next 36 h. The global, regional, and consensus intensity aids all agree that rapid intensification will occur in one form or another during this time frame as well. The official intensity forecast is a blend of the HFIP corrected consensus and the IVCN consensus, and is very close to the previous forecast. Large swells generated by Genevieve are expected to begin affecting portions of the coast of southern Mexico today and will spread northward along the coast of Mexico to the Baja California peninsula by Wednesday. FORECAST POSITIONS AND MAX WINDS INIT 17/1500Z 14.3N 103.0W 65 KT 75 MPH 12H 18/0000Z 15.4N 105.0W 85 KT 100 MPH 24H 18/1200Z 17.0N 107.3W 105 KT 120 MPH 36H 19/0000Z 18.4N 109.0W 120 KT 140 MPH 48H 19/1200Z 19.7N 110.2W 120 KT 140 MPH 60H 20/0000Z 21.0N 111.1W 110 KT 125 MPH 72H 20/1200Z 22.2N 112.4W 95 KT 110 MPH 96H 21/1200Z 24.3N 115.2W 65 KT 75 MPH 120H 22/1200Z 26.4N 118.7W 45 KT 50 MPH $$ Forecaster Latto