Windspeed

I think forward motion to the north is gaining just enough to finally ease the 300 mb flow, though it had already eased on the core somewhat the past 24 hrs, which allowed Fiona to become a Cat 4. There are some strong outer banding features, so cannot rule out multiple ERCs during the next few days, but Fiona may not have peaked yet if a stable eye can take advantage of the ever improving upper environment.

Forward motion matters with respect to the Pandhandle and shelf waters as well. Sure, if the potential TC is intense but gets left behind prior to landfall, it would stall, upwell itself plus entrain continental airmass. However, if it remains at a decent northerly forward motion into the panhandle, shelf waters are still currently running hot. There has yet to be a significant cold front pass through or at least one to bring down SSTs. So the shallow shelf would be more than sufficient to fuel a Cat 5 just like Michael or Camille. Of course, a hook to the right, 300mb flow, trough ventilation, structure, trough bypass, all speculation for a week or more and we don't even have a TC yet.

Discussion of 98L becoming Hurricane Hermine are bit premature. The AEW/AOI in the eastern MDR is gaining support for development. It's quite possible 98L will be slower to go through TCG until the central Carribean versus the AEW in the visible imagery that is a more concentrated surface low right now. The MDR AOI doesn't even have an invest tag yet, but it may not be long today. The Caribbean system could be the dreaded "I" storm. Though of course that's all poppycock superstitious hogwash.

This map is blowing my mind. I get the extreme high latitude in association with the Gulf Stream current for catagorical cyclone intensity potential. But the upper portion of the map seems impossible, as though those SSTs are running above normal, they're still very cold and way below the threshold to support a tropical surface low.

Pressure continues to fall but Fiona's slow forward motion is allowing the 300 mb flow to impede it somewhat keeping it in check. The double wind maxima is perhaps telling that it won't resolve these structural issues until it gains faster northerly forward motion, which should allow it to take off intensity wise.

This is actually easier to see via AVN as you can better make out the -80C/coldest tops. Notice all the GLM lightning detections with each convective burst/tower going up around the northern eyewall to reach highest altitude in the western to southwestern semicircle. These towers are rotating into the 300 mb flow and some of the canopy is overshooting the eye. That being said, the intense convection is likely dropping pressure and increasing the gradient. Fiona is intensifying.

Hot towers are firing against the 300 mb flow. It's a light shear essentially, so mid-level cloud debris is sinking into the eye. The positive ventilation to the north is outpacing the negative counter vector flow from the southwest. I'd call this favorable for a strengthening major hurricane, but perhaps not a perfect envelope until the hurricane turns more northerly. All in all, a period of RI tonight or in the morning remains quite possible.

^Nope, it sure isn't...

Well we need the AEW to spawn a surface low before I get too excited, but obviously if we do see genesis out of this, the modeled potential is worth the superlatives. It appears the Atlantic got tired of the whining and woke up. If this and a few other systems pan out, we should push ahead of normal climatological ACE into an active season. But unless the Caribbean goes bonkers in October, I am pretty confident we won't eek out a hyperactive season at this point. Here a nice tweet describing the setup for the potential future TC into the Caribbean.

I thought there would be some lag time post exit of landmass for reintensification. Perhaps atleast 6-10 hours of ocean time. I mean this was a trek over the DR, even if the core remained over the lowlands. But I was considering the mountainous terrain impeding some of its low-level inflow into the core. Uhhh... that appears to be a big negatory, slappy. Fiona looks like it is about to experience some explosive deepening.

When modeling consensus and ensembles miss the mark, it just is what it is. Goes to show that tropical surface lows are still sometimes tough to nail even in the shorterm.

Ongoing onslaught of the back feeder bands continue. Daytime heating and instability may unfortunately increase low-level convective feed/fetch, so this sadly looks to continue throughout the day until Fiona can gain some distance. No way to paint the situation but dire at this point.

Agreed. I think most had expected a more northerly component to the WNW motion by this point. It's still drifting west of guidance, if subtle, having implications to shorterm intensification tonight when it clears the DR landmass. Low level inflow will be hindered more if it cannot gain some latitude. So a gradual decline intensity until it is east of Turks and Caicos seems logical now.

This is a good distance away from the NOAA radar tower in PR, so the returns from the beam are weak, but you can still easily make out the eye. Punta Cana was very likely near or in the northern eyewall this morning. They're now in the back/behind the right-front quadrant as Fiona is moving away. Fiona's structure is pretty amazing right now considering the core is entirely over land. Though this part of DR is lowlands and the outer circulation is still getting feed off the Carribean. Impressive, still.

If not for the close proximity of mountainous terrain and land interaction in general, Fiona would be closing in on major hurricane intensity tonight. This is no longer the appearance of a struggling hurricane. Outflow is excellent. Towers firing in the eyewall. It likely will not do anything too crazy since it will crossing over NE DR, but it certainly looks like Fiona will eventually become an intense hurricane near to or just east of the Turks and Caicos tomorrow. Perhaps a bit of recovery time depending on how long it takes to clear DR. But the atmospheric envelope looks primed.

That beast trough is so strong it may very well capture and phase Fiona into New Foundland, perhaps even Nova Scotia. Good take is that though Fiona may get intense, it may miss Bermuda cleanly to the west.

Most recent radar derived estimate...

Josh may have a little nasty encounter with the eyewall if he stays put as the core may take on a more WNW/NW vector soon as the vortex is clearly getting stacked and should feel the deep layer motion. Really this jog should be temporary given structure.

The eyewall looked to be reorganizing the past few hours on radar prior to the hiatus in update about 30 minutes ago. No surprise that the CDO is taking off again with a notable hot tower in progress on satellite. Likely due to intense convection wrapping around the northern semicircle of the vortex. It appears Fiona is strengthening again.

More or less drifting S of W but this may just be a temporary stall. Unfortunately the slow movement is still a nightmare situation with an intense band still crossing right over the heart of PR. Not a small band either. Just insane echoes continue over the island, on and on....