Work at the intersection of weather and reinsurance risk for Arch Reinsurance. Love to golf/ski/surf. Views expressed are mine alone.
@osuwxguy
.bsky.social
Eyewall convection already starting to perk up as Fiona's center moves back over water. I'd imagine a significant period of intensification to begin in ~ 6-12 hours. How strong does it get? Guidance certainly suggests a cat 4 is possible
Incredible sun glint looking almost like a zipper as it reflects off the very smooth ocean over the eastern Atlantic - notable for the weak trade winds (smooth ocean) and for the lack of Saharan dust --> both favor continued anomalous warming, yikes!
My favorite phase of TC forecasting is watching a disorganized group of clouds slowly become better organized until it eventually becomes a tropical depression - eg 92L currently
Got all our hurricane prep completed and now can sit back and take in the show. Here is a photo of one of the first outer rain bands as it passes off to the west
#Paulette
#Bermuda
These negative anomalies, especially surrounding Florida into the Bahamas are living on borrowed time - strongest sun of the year + lots of clear skies + weak winds = rapid warming over the next 10 day
Looks like the engine just roared to life with Idalia. -80C convection arcing around the LLC inside the RMW. Good chance we have a hurricane by tomorrow morning
PTC4 appears to forming a surface center near 20.3N 78.3W with westerlies evident in the low level clouds near Cayman Brac. More southerly starting point and slightly less time over Cuba should help lead to a stronger system than the current forecast and possibly a bit further W
Folks in the Lesser/Greater Antilles should keep an eye on the wave near 30W. Solid support across the global model control / ensembles for development. Will do a detailed thread late this afternoon but you can see in the EPS below that a stronger system earlier goes more North
EPS starting to perk up a bit on possible MDR development as we head toward August, which makes sense in the context of the broader forecast pattern, though late July/early August is still a a bit early climatologically for prime peak season conditions
Why are Atlantic MDR SST so warm? Pretty explanatory image showing low level winds for the past month vs climatology (normal) - the past month has much weaker trade winds (less reds/yellows) across much of the tropics - especially noticeable near NW Africa
Sweltering heat looks to continue across Mexico with the ECMWF ensemble mean showing mid level height anomalies as high as 4.7 STD DEV above the climate of just the past 20 years. Suggests a probability of ~1 in 769K
I'm still scratching my head a bit on why I caught so much grief yesterday for saying that a wave that will largely have favorable shear conditions and has decent vorticity and a fairly large moisture pocket was worth watching 🤷♂️
Pretty fascinating to have a strong Cat 2 with a well defined eye in such close proximity to a powerful cold front - baroclinic impacts starting to show in the convection to the N and NE as the warm, moist air is lifted up over over the cooler, more stable air north of the front
Striking difference, especially for the Caribbean, between last year's February ECMWF forecast for June/July/August and this year's forecast
Probably a good sign that the Caribbean won't be as quiet as last year...
We are not any closer to knowing if Ian will landfall near Tampa, but it is interesting to note that the last cat 1 hurricane to landfall in the red box was in 1946, the last cat 2 in 1944 and the last (and only) cat 3 in 1921
Can see the mesovortices within the eye, as well as the firehose of moisture aimed at the southern portions of Puerto Rico and undoubtedly being enhanced by the E-W oriented mountains to 3000 ft + Ugly look, thoughts are with all being impacted!
When folks talk about the "Spring Predictability Barrier" in regards to predicting the El Nino - Southern Oscillation, here is a perfect example of the challenge. March Nino 3.4 anomaly (dashed blue line) was outside the ECMWF SEAS5 forecast plume from December
Latest ECMWF seasonal modeling is aggressive with its Atlantic hurricane season forecast through October as expected - its activity forecast is the highest of any season since 1992 (blue line) and is in the company of the 1995 / 2005 / 2017 seasons actual ACE (red dotted line)
TS Cindy is a gorgeous little storm this morning with a fairly axisymmetric CDO and outflow. Probably a bit of dry air being pulled in with the notch in the NE, but low shear should allow for some intensification over the next 24 to 36 hours
Trend is our friend with 91L! Northward trend makes it less likely to threaten the Bahamas and the US East Coast. Still don’t have a storm center so plenty of uncertainty so could trend the other way
We'll have had anomalous rising motion (green -VP anomalies) focused over W Caribbean/E Pacific for over half of June and very warm SSTs and still it looks like it'll be a struggle to even get one tropical cyclone out of the pattern
The Yucatan Peninsula and the upper level low (red area over the western Gulf) very likely saved the US from a major hurricane landfall. The track Beryl is currently following would have been quite bad for Houston, if the environment had been moister and Beryl's core more intact
I posted a similar pair of images last year emphasizing the uncertainty associated with forecasting ENSO beyond the NHEM Spring. Left image shows the ensemble forecast from Jan2022 in red lines, while the dotted line is actual - right is the new Jan2023 forecast
A thread of random thoughts on Tropical Storm Fiona - Recon is finding that the storm continues to slowly deepen - down form 995mb to 992mb - despite fairly limited deep convection
As we edge closer to the peak of the Atlantic Hurricane Season, where do we sit in respect to SST anomalies compared to recent years? We are well cooler in the MDR than the hyperactive seasons - 2005/2017/2020
Convection has consolidated and consistently fired over top the central portion of the wave axis, kinda curious if it hasn't spun up something under those clouds at this point. Certainly looks worth dubbing it an invest IMO
92L certainly appears to be trying to build a LLC+core, but will need to wait for visible satellite or a wind retrieval to be sure. Let's see what the morning brings!
Hot off the presses - June ECMWF seasonal modeling continues to show double the Atlantic tropical cyclone activity (ACE) as the rather active climatology from 1993-2023 - 2.0 in the green bar. 10% below normal in the E Pacific and 30% below normal in the W Pacific
Historical storms from 2010-2021 passing near the northern Lesser Antilles to Puerto Rico left vs 12Z EPS guidance right. Long way to go to see where this goes and how strong it may get!
Quiet early May across the eastern Atlantic with a southerly suppressed Intertropical Convergence Zone (ITCZ) driven by a combination of an Atlantic Nino (equatorial warmth) and the suppressed phase of the MJO passing over.
Arc of vortical hot towers evident around the south side of Fiona's center. My forecast would be this this to be a hurricane within the next 24 hours, and I do think that storm will track over or very near the SW portion of Puerto Rico on Sunday
Background surface pressures in the Atlantic MDR generally over a standard deviation above normal is not a great pattern for waves to develop - high pressure -> subsidence/dry mid levels
Tiny eye starting to peak out on infrared with Hurricane Agatha after some recent very powerful vortical hot towers rotated around. Glad they have a recon flight headed that way soon!
Low amplitude tropical wave between 50-55°W with expansive Saharan Air Layer to its N. Climatologically brisk trade winds in the E Caribbean -> high shear for the wave. Slight chance for development w/ potentially more favorable conditions as it get further W late week
Latest C3S seasonal modeling is out with the mean precipitation anomalies across all models for Aug-Oct shown below - wet West Africa into the Central Atlantic suggesting that peak season ought to be fairly favorable for easterly waves and possible quick development over water
Interestingly though, the latest EC shows fairly limited impact of the upper level trough as Bret enters the E Caribbean storm graveyard, though of course the enhanced trades still means a struggle with shear
Rather odd evolution in the 06Z ECMWF which holds Fiona steady state over the Dominican Republic and then rather quickly strengthens even as half the circulation is still over land 🤔
94L making progress towards getting upgraded this morning, with some convective banding starting to appear around a nascent low level center. Fairly far south at the moment, should gain latitude as it strengthens, but I suspect the NE Caribbean will likely get clipped
#Waterspout
off the south shore of Southampton
#Bermuda
this afternoon. Lasted 5-6 minutes before dissipating as it ran ashore near the Fairmont’s Ocean Club
Latest 45 Day modeling from ECMWF takes us into the start of Atlantic hurricane season!
Clear signals in the precip anomalies for:
+IOD
+Atlantic Nino
Low precip driven by cooling in the equatorial E Pac as we-> likely La Nina by peak season
US looks dry out West + Southeast
July ECWMF Seasonal Modeling hot off the presses, their Atlantic Basin ACE forecast is for 40% above the recent era normal down from 100% above in June
🧵as I dig into it:
Interesting to see the EC seasonal showing Atlantic ACE 10% above the 1993-2022 climatology, somewhat surprising given the same model ENSO plume is unanimously into the moderate to strong el nino by peak season
Quite a bit of vortex tilt with 91L this afternoon as SE/ESE trade winds at the surface are cross by upper level SW winds - blue L denotes approximate surface low and red L denotes approximate mid level center
Lee's multi-model ensemble track density plot has shifted west a bit and has tightened a bit. Devil is still in the details though of the exact track and associated impacts
Tons of dry air wrapping into Ian fortunately, with no convection near the center (which is becoming a bit less well defined) It would sure seem that any intensification from here before landfall in South Carolina would be due to baroclinic processes
From April 1 - June 5 here are the 500mb geopotential height anomalies for 2020 / 2021 / 2022 with quite anomalous lower heights dominating the NW United States in 2022 in a marked difference from the past two years
Another powerful easterly wind burst forecast by the EC ensemble near the Date Line in the Pacific -> will further reinforce the La Nina and continue to help support the forecast for another La Nina for Northern Hemisphere winter
00Z EPS continues the consistent narrative for a hurricane, likely to stay to the north of the islands, possibly affect the Turks & Caicos, and likely recurve possibly near Bermuda. Overall for a long track MDR hurricane, this would be a great outcome!
Invest 92L has a pretty good shot of getting upgraded sometime tonight or early tomorrow!
SE flow in the low/mid levels has induced some shear overnight and this morning, but this should lessen over the next 12 hours + 92L will be crossing the Gulf Stream near Diurnal Max
A while back, I had posted about Franklin busting through the trough and potentially taking advantage of duel outflow channels to become a major hurricane. Whelp, here we are...
It's a good thing that the wave east of the Lesser Antilles has struggled with mid-level dry air or we would have likely had a TC able to take advantage of the entire length of the Caribbean in low shear... Still worth keeping an eye on for now though.
So apologies in advance, but I'm going to be tweeting quite a bit about
#Paulette
the next several days since it's headed my way. Some convection wrapping upshear (toward the SW) on the latest infrared may be an indication that the shear is starting to relax just a bit
@BigJoeBastardi
Hi Joe. Not sure I follow? I was pointing out how warm the Atlantic Basin in as it relates to the upcoming hurricane season. Recent cold in Morocco doesn't seem to change the point that we are the second warmest in the MDR as of mid May
As if predicting the monsoon trough wasn't difficult enough, signal for some E Pac energy to crossover or a CAG type genesis pathway for the Western Caribbean/Gulf in a week to 10 days continues to pop up in the op runs and ensembles. 👎
It's been interesting to watch the models showing some modest signs of interest in the tropical waves crossing the MDR despite the some large scale subsidence being favored (left) over the next 5 days - the 6-10 / 11-15 day forecast looks more favorable
Looking to the eastern Atlantic for what might be next tropically, Invest 95L is being strongly sheared and will be absorbed into Earl and thus is unlikely to develop. The other wave circled is on the edge of a very dry, stable airmass which will make any development difficult
Latest ECMWF seasonal forecast calling for Atlantic ACE 50% above the 1993-2021 climatology, so either the basin will pick itself up off the mat, or many of these seasonal forecasts will bust low
Progressive CCKW pattern with another likely to be generated in the Bay of Bengal and then progress across the Pacific and could give us another chance for a Central American Gyre and tropical cyclone genesis in the W Caribbean or E Pacific around June 1st
As we begin November, global SST anomalies compared to same time last year show a similar La Nina pattern in the E Pac, but are much cooler this year in the N and NE Pacific including along the West Coast of the US. Atlantic SSTs are warmer near Europe and near the Equator
In a very weak steering environment, the center of Franklin is chasing the deep convection being sheared to its southeast. Quite a rare heading for late August!
GFS has 93L plowing through a fairly strong upper level trough then finds lower shear under the trough axis and intensifies quickly into a hurricane over fairly cool waters near Bermuda
#ColorMeSkeptical
Powerful atmospheric river aimed at southern Florida bringing a substantial flood risk over the next couple days as deep tropical moisture floods north ahead of the E US trough - ironically to an area that has been extremely dry and is suffering drought conditions
Going to play guess that final modeled pressure for the low in the Gulf shown in the latest frame available. I'm going to guess 963mb. Hopefully just a spurious W Caribbean convective spinup, but that's a not so fun environment it would find...
Recon is heading for an intensifying Fiona. Looking forward to seeing dropping pressure and increasing winds with each pass, and maybe we get support for an upgrade to a cat 3 before it departs?
Almost comical how the Main Development Region is just about the only region of near to below normal SSTs in the North Atlantic
(PLEASE note that we are a long way from HU season, and these temps can change a LOT even in just a couple weeks, so don't read too much into it)
Somewhat interesting attempt at bit of a reversal in the ++AMO over the past 15 days with the MDR cooler (albeit from record levels) and the subtropics warming