Hurricane Melissa

[Windspeed]

Let me get it out of the way first. Melissa is definitely a Category 5 right now based on initial recon. But clearly there is something to be said about inflated ADT numbers due to CT temperatures. ADT is spitting out sub 900 hPa estimates and we're no where near that. I think while recon is out there they will sample in the 910s range before they leave. But we're going to start having to curb CT temps based on background characteristics of the Autumn tropopause height. A ring of sub -80 to -90°C is still impressive regardless of date. But it is becoming quite apparent that given the later months (late Oct, Nov., Dec.) that the tropopause height in the deep tropics allows tops to get colder than the Summer and late Summer months. It inflates dvorak numbers. We have had suspicions for years that WPAC deep tropic super typhoons may have been over estimated. Again, it doesn't take away from the fact highest-end TCs are Category 5s on the Saffir Simpson. But the later the seasonal date, ADT is estimating too low a pressure. 895 versus operational ~20 hPa off is ridiculous.

[Coach McGuirk]

Still a cat 4 with 150 MPH winds but cat 5 pressure at 926 MB. 

[Coach McGuirk]

4 minutes ago, Windspeed said:

Let me get it out of the way first. Melissa is definitely a Category 5 right now based on initial recon. But clearly there is something to be said about inflated ADT numbers due to CT temperatures. ADT is spitting out sub 900 hPa estimates and we're no where near that. I think while recon is out there they will sample in the 910s range before they leave. But we're going to start having to curb CT temps based on background characteristics of the Autumn tropopause height. A ring of sub -80 to -90°C is still impressive regardless of date. But it is becoming quite apparent that given the later months (late Oct, Nov., Dec.) that the tropopause height in the deep tropics allows tops to get colder than the Summer and late Summer months. It inflates dvorak numbers. We have had suspicions for years that WPAC deep tropic super typhoons may have been over estimated. Again, it doesn't take away from the fact highest-end TCs are Category 5s on the Sapphir Simpson. But the later the seasonal date, ADT is estimating too low a pressure. 895 versus operational ~20 hPa off is ridiculous.

What about Wilma?   Hurricane Wilma - Wikipedia
 

[Windspeed]

What about Wilma?   Hurricane Wilma - Wikipedia
 

Nothing to say, really. Wilma had recon support for its peak.

[WxWatcher007]

Wilma is one of one. 

[WxSynopsisDavid]

7 minutes ago, Coach McGuirk said:

What about Wilma?   Hurricane Wilma - Wikipedia
 

Understand Dvorak is an estimate and it should be used as a tool. Typically when you see those sub 900 estimates on Dvorak, add 20 to get an accurate estimate. In the case of Melissa, Dvorak was pretty much spot-on if you added 20 to the pressure estimates.

[WxSynopsisDavid]

3 minutes ago, WxWatcher007 said:

Wilma is one of one. 

 

Wilma is the GOAT. At least we never got to witness Wilma’s peak on landfall.

[WxWatcher007]

This is probably going to be a really impressive SW to NE pass. 

[WxSynopsisDavid]

1 minute ago, WxWatcher007 said:

This is probably going to be a really impressive SW to NE pass. 

Historic and likely one for the record books. Top-5 or Top-10 reading inbound.

[Coach McGuirk]

TWC has it hitting Jamaica with 160 MPH winds.

[WxSynopsisDavid]

1 minute ago, Coach McGuirk said:

TWC has it hitting Jamaica with 160 MPH winds.

I think very few of us in here actually look at TWC for tropical weather insight. Melissa is likely in the 170-180mph range right now. Just need the northeast quadrant eyewall measured to confirm.

[WxSynopsisDavid]

I still stand with 910-920mb and 170-180mph winds for my bet on the northeast quadrant reading. Any final bets or adjustments to previous bets?

[Coach McGuirk]

2 minutes ago, WxSynopsisDavid said:

I think very few of us in here actually look at TWC for tropical weather insight. Melissa is likely in the 170-180mph range right now. Just need the northeast quadrant eyewall measured to confirm.

NWS still has Mesissa at 150 MPH 1 AM Eastern time. But with a 926 mb pressure indicating cat 5. 

[WxSynopsisDavid]

Just now, Coach McGuirk said:

NWS still has Mesissa at 150 MPH 1 AM Eastern time. But with a 926 mb pressure indicating cat 5. 

Recon Hunters are currently inside Melissa. Those previous readings were measured in the south quadrant. In Atlantic hurricanes, the south quad typically features weaker winds and higher pressure. The higher winds and lowest pressure (peak intensity) reside in the northeast quadrant. 
 

So process that for a minute. The weaker quadrant of the hurricane measured at 923mb with 150mph winds. What do you think they will find in the northeast quadrant?

[WxWatcher007]

918.9mb extrap

[WxSynopsisDavid]

918mb in southwest/western quadrant.

We have 923mb in S/SE quad and 918mb in W/SW quad. Very impressive readings in the weakest quads of an Atlantic hurricane. 

[WxSynopsisDavid]

140kts in NE quad

[NeonPeon]

First appearance of any asymmetry in a while on ir. Deeper convection away from eyewall in ne quadrant. Imagining this is an ewr beginning? Hopefully it can't finish before becoming a slightly larger windfield version of the same beast we just saw.

[WxSynopsisDavid]

1 minute ago, NeonPeon said:

First appearance of any asymmetry in a while on ir. Imagining this is an ewr beginning? Hopefully it can't finish before becoming a slightly larger windfield version of the same beast we just saw.

No, recon hunter data confirms no ERC is ongoing or imminent. What is happening to cause the asymmetry is deep convection firing. Melissa is undergoing another RI process. We just happen to have recon hunters inside the storm this time.

[WxSynopsisDavid]

3 minutes ago, NeonPeon said:

First appearance of any asymmetry in a while on ir. Imagining this is an ewr beginning? Hopefully it can't finish before becoming a slightly larger windfield version of the same beast we just saw.

Also, asymmetry can happen in Category 5’s when they start to feel friction with the coast. 

[Windspeed]

Also, asymmetry can happen in Category 5’s when they start to feel friction with the coast. 

The trough is also moving into influence which can begin to affect symmetry and convection on the periphery of the TC, including the outflow channels. Otherwise, Melissa's core is about as textbook as it gets for a powerful Atlantic Caribbean hurricane. Current appearance kind of reminds me of Matthew.

[NeonPeon]

2 minutes ago, WxSynopsisDavid said:

No, recon hunter data confirms no ERC is ongoing or imminent. What is happening to cause the asymmetry is deep convection firing. Melissa is undergoing another RI process. We just happen to have recon hunters inside the storm this time.

It's already at 160mph. It's some ask for it to rapidly intensity from there!

Esp when it is looking less symmetrical.

[WxWatcher007]

Remarks Section - Remarks That Were Decoded...
 

Maximum Flight Level Wind: 152kts (~ 174.9mph) which was observed 5 nautical miles to the N (358°) from the flight level center at 7:05:00Z

Remarks Section - Additional Remarks...
 

SAWTOOTH APPEARANCE AND FREQUENT LIGHTNING PRESENT ALONG NORTHERN EYEWALL

[NeonPeon]

3 minutes ago, Windspeed said:

8 minutes ago, WxSynopsisDavid said:

Also, asymmetry can happen in Category 5’s when they start to feel friction with the coast. 

The trough is also moving into influence which can begin to affect symmetry and convection on the periphery of the TC, including the outflow channela. Otherwise, Melissa's core is about as textbook as it gets for a powerful Atlantic Caribbean hurricane. Current appearance kind of reminds me of Matthew.

I think it's more the latter, yeah you can see part of the outflow racing off to the northeast. As the whole storm turns it'll reorient, but if the coastal interaction happens before it can wrap the convection around more, I don't see how it isn't currently at around its peak strength, which is impressive enough.

[WxSynopsisDavid]

1 minute ago, NeonPeon said:

It's already at 160mph. It's some ask for it to rapidly intensity from there!

Esp when it is looking less symmetrical.

Your assumption on ERC is wrong, point of my remark. The asymmetry is from friction and the trough. There’s also deep convection that fired in the east quadrant. Melissa is showing no signs of weakening. I mean, we literally have pressure falling and winds increasing on each recon pass right now.

[WxWatcher007]

Yeah recon shows no evidence of weakening. Probably the opposite at this hour. I mean, expect another 2-4mb drop on the next pass. The ERC will happen eventually, but it’s not right now. 

[RU848789]

The view of a peaceful starry night, inside the maelstrom of Melissa.  

[Windspeed]

Looks like we are around 30 hours from landfall give or take a few depending on timing of the trough influenced deep layer southerly flow. We should start to see northward motion begin by midday or noon'ish. Timing on this is critical for the eventual landfall point.

[WxSynopsisDavid]

917mb in N/NE quad. Along with the 140kts they measured earlier in the NE quad, Melissa will now be upgraded to a Category 5. Either we get a special advisory or they wait for 5am.

[WxSynopsisDavid]

Recon measured 158kts in the north eyewall at the surface. This equates to 180-185mph range for surface winds.