And another one:

Thanks to @franklinjamesl.bsky.social and @pppapin.bsky.social for help in building this product — in the continued absence of JTWC public a-deck data, I’ve reproduced interpolated model guidance plots for tracks and winds. These are live on PolarWx for all active storms: polarwx.com/tropical

If you prefer using interpolated "early-arriving" model tracks for tropical cyclones (last cycle's models interpolated to this cycle, then compared against the official JTWC/NHC forecast made using these guidance), I've replicated this method on my site: polarwx.com/tropical/?st...

With the addition of HAFS-A and HWRF, I've now independently reproduced most model tracks for global tropical cyclones & typhoons that would typically be in an a-deck file, given that these have not been available for storms in JTWC's domain this year. polarwx.com/tropical/?st...

The East Coast will get its first preview of winter weather next week as a transient but deep cold airmass traverses the region — widespread well below average temperatures are expected for a couple days: (1/3)

Swing… and a (huge) miss Be careful with interpreting AI model run-to-run consistency as a sign of high confidence & likelihood — FNV3 was insistent on exceptional rapid deepening up to the last minute when it failed to materialize:

While recognizing there are different views on whether a category 6 is needed for hurricanes, my personal view on this boils down to a simple phrase: “just because you can, doesn’t mean you should”

So far this year, the Gulf has been very quiet with only one short-lived tropical storm (Barry). Assuming this holds (which is likely), this would be the quietest Gulf season since 2015, and the first season without US Gulf coast tropical cyclone impacts since 2014.

This is part venting as a NJ resident in election season & part plea for help — is there any way to get myself unsubscribed from political operatives’ phone lists that I never subscribed to in the first place & am getting spam calls and texts from different numbers too many times a day

Multi-panel view of the last few days of Hurricane Melissa: ↖️ GOES-19 infrared brightness temp ↗️ GOES-19 visible satellite ↙️ Hurricane hunter planes & flight paths ↘️ Recon-derived flight level wind swath ⬇️ Estimated minimum pressure from recon dropsondes

Given higher than usual confidence of rapid intensification (RI) from analyses of an exceptionally favorable environment & with the aid of newer hurricane models (HAFS) & Google DeepMind, NHC was able to skillfully predict Melissa's RI days in advance.

A look at TDR observations of Melissa over the last few days shows just how impressively persistent and compact its inner core was - while the lack of eyewall replacement cycles helped Melissa intensify right up to landfall, it also kept its wind field fairly small.

The last hurricane hunter flights into Melissa have departed before its landfall in Jamaica. As always kudos to them for their work powering through especially powerful storms like this to collect invaluable data.

Thousands of lightning flashes have been detected in the eyewall of Hurricane Melissa in the last couple days, oftentimes completely enveloping the eyewall - the Enveloped Eyewall Lightning Signature - a phenomenon found in the strongest tropical cyclones on the planet.

Wow. This is easily the most ridiculous dropsonde I’ve ever seen. 188 knot mean winds in the low-levels with gusts over 250 mph Absolutely scary and historic hurricane headed into SW Jamaica this morning

The fact that we are currently witnessing one of the most intense Atlantic hurricanes on record, that it's at this intensity so close to landfall, and is *still* intensifying right up to landfall in Jamaica is absolutely mind blowing. Wishing the best of luck to everyone in its path.

The latest recon pass recorded a staggering 173 kt (199 mph) peak flight-level wind... while this measurement is quite far aloft, parts of western Jamaica in the path of its ferocious core are over 500-1000m elevation & will experience stronger winds than at sea level.

Indeed we’ve got a dropsonde supporting 892mb, making Melissa tied with the Labor Day hurricane for the 3rd deepest Atlantic hurricane on record (behind Gilbert & Wilma) — and at this rate, headed for the deepest Atlantic hurricane at landfall on record.

Waiting on a dropsonde to confirm, but Melissa is most certainly below 900 hPa right now. Tragically we are about to witness the 2nd or 1st deepest Atlantic hurricane landfall by min MSLP on record in Jamaica.

Melissa is a great example of the value of in-situ observations - without recon flights, we largely rely on satellite estimates to assess a storm's current intensity. And current satellite estimates for Melissa are much more intense than what recon has recorded so far.

When many meteorologists call you out for (again) spreading misinformation about hurricanes, resorting to hiding those replies is not exactly the look of someone who cares about the quality of the information they are disseminating... just saying. (Good fact-check here: bsky.app/profile/clar...)

The ongoing USAF mission is going in for another pass into Melissa - given steady pressure falls over the last few passes, there is a non-zero chance its minimum MSLP may reach or fall below 900 hPa in this mission.

Quick comparison of Melissa's structure from TDR now vs. 12 hours ago - while the inner core has barely changed with a similar peak wind speed & RMW, its hurricane-force wind field has slightly expanded. This is not a good development as it approaches Jamaica.

We just had two recon flights near-simultaneously cross Melissa's center - interestingly both recorded slightly different minimum MSLP estimates, though center dropsondes will yield more exact min MSLP values.

This is not meant to be a replacement to other sites that provide much more comprehensive realtime recon data, but in the event that other sites experience outages, I added a basic viewer of the most recent active recon missions: polarwx.com/tropical/?st...

Melissa's north turn is getting slightly delayed by it completing a loop, which has led to its motion briefly deviating to the southwest. Once this loop is completed Melissa should turn on a more north-NNE trajectory.

PolarWx's tropical page is down unfortunately while I try to fix an underlying issue on the web server. Apologies for the inconvenience.

A new convective burst is wrapping around Melissa's eyewall with CDO averaged cloud temps cooling again. With no immediate sign of an eyewall replacement cycle & deep warm water preventing weakening due to cold water upwelling, it's quite possible Melissa falls below 900mb tonight.

🚨MISINFORMATION ALERT🚨 The slow forward speed is only for right now and Melissa will be speeding up as time goes on. The radius of maximum winds is very small - less than 20 miles from the center of the storm. Yes, the combo of wind and rain will be devastating, but not like this. ⬇️⬇️

That’s…not at all how this works. As the NHC’s wind field image shows, Jamaica is only experiencing tropical storm-force winds right now, with weaker winds elsewhere. The most widespread and longest-lasting impact has and will be extreme rain - for which the prep is rather different than wind.

With Melissa's short term motion important for where landfall & the worst of its destructive category 5 winds will occur, I added back plots comparing the latest visible satellite to recon center fixes & NHC and grand ensemble mean forecast tracks: polarwx.com/tropical/?st...

Something to watch out for over the next day is precisely where Melissa makes the turn to the north, as do far it continues to drift west or just south of west. The longer this continues, the farther west its landfall location shifts in Jamaica.

Hurricane Melissa’s inner core has substantially contracted as it continued its rapid intensification — its radius of maximum wind (RMW) has decreased to 14km as of this morning’s mission:

A dropsonde released by NOAA started with southerly winds and ended with northerly winds, implying the dropsonde made it approximately halfway around the eyewall from when it was released to when it hit the ocean. That is some incredible movement.

I brought back limited recon plots to PolarWx - for storms with active recon missions, you can find a recon-derived hovmoller, and loops of TDR composite maps for various altitudes & all missions for this storm: polarwx.com/tropical/?st...

Melissa's long-anticipated exceptionally rapid intensification episode is now underway, as its eye is now closed with deep convection rotating about it. The latest TDR data shows an RMW of ~27km, though this will contract as RI continues, with the strongest wind upshear.

NHC now explicitly calls for Melissa to reach category 5 intensity before striking Jamaica. The addition of Google DeepMind’s FNV3 ensemble this year bolstered forecast confidence in extreme intensification — it’s doubtful the NHC forecast would’ve been this aggressive without FNV3.

While #Melissa has begun to strengthen and has a well-defined LLC, its MLC is still quite far off to the ESE. Sign of the shear that hasn't quite let up. Will not see more rapid intensification until the tilt reduces

Confused about why some model track plots you’ve seen differ from the actual model 2D maps? The “interpolated” tracks commonly shown (left plot) are interpolated to start from the same point, but sometimes this slightly changes their track. The map on the right shows the raw model tracks:

[Melissa forecast analysis, Friday 10/24] The forecast is looking increasingly dire for Jamaica. Model guidance has increasingly clustered on a direct hit - Jamaica has only had close calls from five category 4 hurricanes on record - with catastrophic flooding a major concern.

There are two noteworthy things about the latest NHC forecast for Melissa: 1. This is the first time NHC explicitly forecast rapid intensification at day 3-4 lead time 2. If latest forecast trends hold, this forecast could still be a significant intensity underestimate

If #Melissa finds its way south-southwest of Jamaica in several days, this environment has the highest ceiling for any Atlantic tropical cyclone I can remember. Big, strong, slow-moving hurricanes like what #Melissa may become are when things like Oceanic Heat Content will start to matter a lot.

Overnight guidance has continued to abandon Melissa turning NE into Hispaniola, and is increasingly concentrated on a west track south of Jamaica - a scenario which could easily support a category 5 hurricane in an exceptionally favorable environment for intensification.

The GFS has a habit of erroneously spinning up vorticity maxima into vertically aligned TCs too quickly & aggressively vs observations, which in Melissa’s case leads to a solution likely too far east. Melissa instead continues marching due west, defying the GFS (plot credit @btangywx.bsky.social)

While I continue to build a full viewer for the new 360-member Grand Ensemble, plots of the latest available data are now live on my website for Melissa (link below) and any other storm there is data for: polarwx.com/tropical/?st...

Latest 0z update to the Grand Ensemble, along with a breakdown of every ensemble suite included in it & percent of ensemble members per suite that detected the storm. There was a noticeable west shift in the 0z guidance, with more members showing a west turn south of Jamaica.

I usually don't post about a new feature before it's complete, but in the interest of timeliness with an uncertain path for invest 98L, I've been working on implementing a 360-member grand ensemble consisting of 9 ensemble suites (NWP + AI). Here is its latest projection for 98L:

#lockitin season has arrived (If you’re confused by this post — don’t worry, we aren’t getting a major snowstorm next week)

Since the default GEFS tracks from the NHC server continue to struggle identifying ensemble tracks for invest 98L, I swapped it for my in-house tracker that I use for the ICON & AIFS ensembles on my website: polarwx.com/tropical/?st...

Objective cyclone trackers are having a tough time resolving all GEFS member tracks for invest 98L due to its disjointed segments between the antecedent open wave and subsequent surface cyclone formation. This explains why you see different GEFS tracks on different sites.