Jack Wales

As I feared AderynCoch, especially as Matthew is moving so slowly which prolongs the exposure to the extreme conditions. The wind is still blowing at 110mph there, that's continous 100mph+ wind speed for over three hours! Recon data shows maximum surface winds at 136mph and interestingly their SFMR data at around 990mb is consistent with the wind speeds being observed at Les Cayes. Agree with SB, with low shear and warm SST's there is nothing to prevent restrengthening.

Yes AderynCoch, Les Cayes has a population of just under 100k so I really feel for them atm. That station only dropped to 989mb so 109mph on the outskirts of the eyewall is immense!

The eye of Matthew has made landfall on the western tip of Haiti whilst the system exhibits the classic doughnut shape often seen with Cat 5's. It'll be interesting to see what recon come back with in the next hour.

With the eye of Matthew now approaching the Haiti coast, here is the current reading from Les Cayes (probably in the eyewall) showing winds of 103mph... https://weather.com/en-GB/weather/today/l/18.20,-73.75

I just missed Hermaine when I was over there a couple of weeks ago. Good luck and stay safe.

Recon data just in shows pressure drop to 934mb however no adjustment to surface level winds with maximums of 135mph recorded. This maintains Matthew at Cat 4 (at least) and forward speed seems to have slowed in the last couple of hours as he wobbles just east of due north. Still presenting well in the imagery, although there are signs of the moisture envelope being somewhat cut off by the Hispanola land mass which should induce some weakening. At the moment the eyewall track is over a sparsley populated area of Haiti, however the wider risk of flooding and mudslides are likely to pose the greatest risks Imo...

Based on this image, I'd say the new eyewall is 80% complete. The timing is worrying as with the ERC complete -coupled with diminishing shear could herald another phase of Rapid Intensification.

Eyewall Replacement Cycle

Mathew continues to intensify with the eye now clearly discernable in visible imagery. Unsurprisingly it's now up to 100kt with no real impediments ahead of it over the next couple of days. This could be pretty devastating for Jamaica and Cuba.

Mathew looking more impressive despite the shear. Cdo is strong and eyewall clearly starting to form...

Yes, looking very impressive at long last. Could make landfall as a cat2. At least that coastal region of florida is sparsely populated which will hopefully mitigate the damage to property and lives.

99l is a heavily sheared system at the moment. The low level centre appears to be over the turk and caicos islands with all the convection sheared well to the south over southern Hispanola. With the shear only forecast to reduce somewhat it's less likely a TD will form in the next few days at least.

Hi Nouska, yes I'm still in Florida and eagerly watching the models. As you say it's interesting that ECM is the most bullish with regards to development of this system. The satellite images from this morning indicate 99l has tightened up with a more defined and seemingly closed rotation in place. I wouldn't be surprised if this is upgraded to a TD today...

99l is definitely firing up with very cold cloud tops and signs of it beginning to establish a circulation. Proximity of dry air doesn't seem to be affecting the system at the moment and with it moving into a much more favourable environment, there's definitely scope for significant intensificstion by the end of the week. What's more of a concern is that models are becoming more aligned with the forecast track taking 99l across the Bahamas and Florida.

HI I'm currently in Florida so watching both 99l and 90l with great interest. The Atlantic ridge into the USA seems to be robust so it's likely that both systems will end up close to my location. The only mitigating factors appear to be dry air entrainment... Any thoughts anyone?

Hi, as i see it this winter has a strong chance of being mild to very mild. The siginificantly positive enso coupled with the positive and strong QBO signal usually combine to override other factors such as Atlantic SST's. I hope I'm wrong but wouldn't be surprised to see the N'ly tracking jet / bartlett scenario prevail for longer periods this winter.

Thunder snow in Tonyrefail :-) currently 0.8 c

I suspect a cold end to the month so I'll go for 3.8C

7.9

The brief cold spell currently being modelled remains a week away which is still in FI in my opinion. The key elements for the evolution such the cold synoptics are the positioning of the scandi high and the strength of the jet. One factor which models seem to be picking up on is that the progged weakening of the jet into next week may have been a little overplayed. The outcome of a stronger jet would result in the scandi high being displaced to the east and the jet subsequently splitting further east (and the cold diverted into central europe). At this stage, the ensembles are probably the best gauge for the probability of an easterly occurring next week. However at the moment support in the ensembles is gradually diminishing as we get closer to the reliable timeframe. At this time of year (and especially so given recent synoptics), I won't dust off my sledge unless we are still seeing these charts after the weekend!!

Yes, deep cold and -40C widely being recorded across canada at the lower latitudes (50 to 55 deg north), -46C in parts of Quebec. Currently approaching -30C in parts of Newfoundland!

4.5 please

Yep, Bizarrely now 14C in Pentwyn and Rumney (both in Cardiff).No clear signs of a pattern change upstream as yet so I cannot see much changing in the next couple of weeks.

Yes, they are telling us it's going to be extremely mild! Even the most ardent cold rampers must admit that December is virtually a write-off for cold given the current embedded pattern.At the moment it's 13C in Cardiff and with no wind it actually feels warm in the unbroken sushine. So much so I didn't bother wearing my coat today, just nice shirt-sleeve weather. I think this winter will go down in the record books.... for it's mildness.

I doubt even the most ardent cold ramper could argue that the charts beyond monday look anything but mild. Just look at the enesmbles which gnerally indicate mild right into FI. Based on the current synoptics, I just can't see any major pattern changes on the horizon. RJS looks to be spot on re December already.