Hurricane Matthew has remained a category 4 hurricane almost non-stop since late Friday night, and is now moving north towards the Windward Passage. Matthew will slowly move between Haiti and Cuba through Tuesday, possibly making a landfall on the western tip of Haiti or the eastern tip of Cuba. Matthew is becoming a larger storm and is slow moving, meaning the mountainous terrain in eastern Cuba, Haiti, and the Dominican Republic will see locally over 30” of rain, resulting in potentially catastrophic flash flooding. Significant storm surge is also likely on portions of the Haitian coastline, and damaging winds are also likely in far eastern Cuba and in parts of Haiti. A very high death toll is likely in Haiti.
Matthew will emerge over the southern Bahamas on Wednesday and will slowly move north-northwest across much of the island chain. Matthew’s interaction with the high terrain of Haiti and Cuba may briefly weaken it to a category 2 or borderline category 3 hurricane, however the environment will be favorable for re-intensification, and it’s likely that Matthew remains a major hurricane as it moves over the Bahamas, or re-intensifies into a major hurricane if it gets weakened below category 3 status by the interaction with eastern Cuba and Haiti. Matthew’s slow movement will cause a prolonged period of strong/damaging winds, heavy rain, and dangerous storm surge across many of the Bahama Islands. Conditions in the Turks and Caicos and southern Bahamas should begin to improve by Thursday, with the northern Bahamas possibly seeing adverse weather through Friday.
Matthew’s forecast track has shifted westward gradually over the last couple of days and now is just off of the east coast of Florida. Matthew is expected to be a large and strong hurricane through the end of the week, and strong winds, heavy rain, and coastal flooding look increasingly likely over parts of the Florida peninsula. A direct hit on the east coast of Florida is still well within the realm of possibilities, which would increase the odds of more significant wind damage and storm surge in parts of Florida.
Matthew is expected to slowly continue moving north into the weekend and will either come very close to or pass over the Carolina coastline. It is looking increasingly likely that at a minimum, gusty winds, heavy rains and dangerous surf will affect the coast from Georgia up to the Outer Banks…with a direct landfall somewhere in the Carolinas still being within the realm of plausible solutions.
Exact impacts north of the Carolinas are much more uncertain, however the entire East Coast should closely monitor the progress of Matthew this week.
Always check forecasts for the National Hurricane Center, your local Weather Service, and heed advice of emergency management officials when making hurricane related decisions.
The inner core of Hurricane Matthew has fluctuated in form and intensity over the last 3 days, and is still doing so this evening. After a few false starts on Saturday and Sunday, it appears that an eyewall replacement cycle may have finally/quickly occurred Monday afternoon/evening. Recently, cold cloud tops have expanded markedly in the eyewall, although the eyewall may still be open on the southwest or south side, possibly explaining why the eye has clouded over this evening. If the eyewall can close off, there is still a short window for additional intensification before interaction with the mountainous western tip of Haiti…as it stands now, Matthew is an extremely dangerous category 4 hurricane.
Microwave imagery from Monday evening shows that the inner core of Matthew is larger than it was when it became a category 5 hurricane for a brief time Friday night, however the eyewall is producing very intense convection and is almost completely closed off. A little bit of dry air has been trying to intrude into Matthew’s inner core at times over the last couple of days, which may be why the eyewall has a bit of a soft spot…however, if Matthew can close off the eyewall completely, the very intense convection in the eyewall suggests we may see one more run towards a category 5 before impacting the western tip of Haiti Tuesday morning. This isn’t certain but is possible…either way, Haiti is looking at a dire situation and unfortunately a very high death toll in all likelihood.
A loop of microwave images from Monday afternoon and evening does suggest that an eyewall replacement cycle may have quickly (and finally) occurred; there are signs of an outer eyewall forming late Sunday night, with a bit of a “moat” surrounding the inner eyewall. Although Matthew never had the true “concentric” or “double” eyewall look associated with eyewall replacement cycles, the outer eyewall appeared to quickly contract while the inner eyewall quickly weakened. Recently, the eyewall has really intensified and is close to closing off again, a sign that Matthew may still have room to intensify before hitting Haiti.
Remember when Matthew was a category 5 hurricane, and winds quickly went from tropical storm force to 135 knots within a few miles of the center? Recon shows that Matthew is now much larger, another sign that an ERC may be occurring/about to finish. There isn’t really a double wind maximum with Matthew, so again we may be close to the inner core closing off and possibly intensifying tonight. Whether or not the inner core intensifies means little to Haiti and eastern Cuba, as devastating impacts are likely regardless…especially in Haiti. The larger core will increase storm surge in Haiti, and also increase the amount of land that sees damaging winds.
Water vapor loops continue to show an upper level trough to the northwest of Matthew over the Gulf of Mexico, however the trough has weakened/shifted west a bit over the last few days. The southwesterly shear imparted by this trough has weakened over Matthew, and Matthew is moving parallel to the shear now. Matthew has a very symmetric outflow, and it appears that the upper level anti-cyclone is co-located almost perfectly with the hurricane…which isn’t particularly surprising given how long the storm has been producing deep convection. The combination of the upper level trough weakening/backing west a bit and the upper level anti-cyclone becoming more co-located with Matthew has allowed shear to drop to almost 0 over the hurricane, with the trough to the northwest and upper low to the northeast of Matthew helping to provide for strong outflow. With Matthew moving over very high heat content waters south of Haiti, the potential for intensification up until landfall or approach on the western tip of Haiti is certainly there if the eyewall can completely close off.
The western tip of Haiti and eastern Cuba have high terrain, which will likely weaken Matthew some…however with Matthew intensifying right up to land interaction, and a relatively minimal amount of land interaction, Matthew may emerge over the southern Bahamas as a strong category 2 or category 3 hurricane.
The steering currents map for Matthew Monday evening shows several features affecting the short and medium term motion of Matthew; currently, Matthew is being steering to the north or even slightly east of due north by ridging to its east. Mathew will approach the western edge of this ridging and get nudged west over the Bahamas. At the same time, there is a ridge building over the Great Lakes that will move over the Northeast as an upper low currently over New England moves off to the east. As the ridging builds into the Northeast, it may connect with the Atlantic ridging and block Matthew’s escape route out to sea. A trough moving in from the western US may also either phase with Matthew and pull it north-northwest into the coast, or kick it northeast, depending on both the orientation of the trough and the position of Matthew later this week.
When Matthew emerges over the open Atlantic over the Bahamas on Wednesday, it will remain in a very favorable upper level environment…with a very large anti-cyclone over the storm keeping any upper lows and troughs away from the hurricane, and providing for strong outflow. There also doesn’t appear to be any very dry air in the immediate path of Matthew over the next few days:
In addition, oceanic heat content remains very high over much of the Bahamas, with near 30C/mid to upper 80F sea surface temperatures extending to significant depths. Heat potential doesn’t become a limiting factor until you get close to the Carolinas:
It’s always tough to tell how tropical cyclones will handle land, especially land with mountains. Matthew will traverse a very short distance over land, with large portions of the hurricane remaining over very warm waters at all times…however, the land is mountainous, which normally has a significant impact on the inner core of tropical cyclones. I suspect that given the pros and cons and Matthew’s apparent intensification up to land interaction that Matthew will remain a major hurricane as it emerges into the open Atlantic. If Matthew jogs over more land it may briefly get knocked back to a category 2 before the overwhelmingly favorable conditions over the Bahamas allow for re-intensification. Matthew will have a full 2-3 days in this very favorable environment before shear, dry air, and lower heat content likely weaken the hurricane as it gets closer to the Southeast Coast, so barring an earlier landfall into Florida it is very possible that Matthew re-attains category 4 intensity once again over the Bahamas. Depending on how quickly the inner core re-organizes after passing near/over mountainous terrain, one more run at a category 5 isn’t impossible.
When I last posted on Friday, I noted that the majority of guidance left Matthew a path to escape east without directly impacting the United States, and that at that time I was leaning towards that solution. But, as any good meteorologist would, I covered my ass and discussed what may happen to allow for a farther west track. Meteorology is an imperfect science, and it is important to diagnose what the “key players” are in a forecast and keep an eye out for any change in those players. I’m sure some more overly aware readers are already pointing out that the above image is an old run of the GFS model. This run of the from Friday afternoon, like most other guidance at the time, had Matthew close to the SE US but ultimately kept the storm off the coast and eventually took it out to sea. At the time, the models had a few features that were slightly “off” for a US East Coast hurricane hit:
-The cut off slow slowly moving off of the New England coast combined with a weak trough over the Gulf of Mexico to leave a weakness between ridging over the Atlantic and ridging over the Northeast, leaving Matthew a path to escape out to sea.
-The flow into the western US was progressive, with shortwave trough after shortwave trough crashing into the coast. Troughs were having trouble dipping far enough south in the models to capture Matthew, and instead either missed the hurricane to the north altogether or kicked it to the northeast, away from land.
The more recent model runs have changed some of the aforementioned players somewhat, and it has an impact on Matthew’s future track:
-The upper low pulls away from the Northeast faster, allowing the weakness in ridging to close, leaving Matthew behind off the Southeast coast.
-Matthew is slower than the above GFS run, more in line with what the Euro has consistently shown, which gives more time for the weakness in the ridging to close.
-The ridging over Alaska is somewhat stronger, allowing for a somewhat more amplified/slower trough coming out of the west, which may have implications down the road on potential impacts to the Mid Atlantic and/or New England.
The GFS is not alone in showing a solution more conducive to either a close shave or a direct Matthew in on Florida or the Southeast coast; this afternoon’s run of the European ensemble also shows the weakness in ridging pulling away, with ridging building ahead of Matthew and preventing a quick escape out to sea. There is however considerable spread in the European ensembles on the speed/amplitude of the trough ejecting out of the western US. This trend on the European ensembles can be seen since the day 10 forecast valid Friday morning, on this fantastic trend loop from the Tropical Tidbits website:
Note how over the last few days’ worth of runs, the Alaskan ridging has trended stronger, the trough, despite ensemble spread resulting in the mean being a bit smoother, becoming deeper as it ejects in the central US, and the ridging ahead of Matthew has also trended stronger. There has also been a trend to higher heights over Greenland, perhaps also contributing to a more amplified pattern over the US. Despite the insane ensemble spread early on, it is important to note that the Euro ensemble’s general slower motion with Matthew than the GFS suite was more correct.
Speaking of the GFS suite, the GFS ensembles have also shown a consistent trend to amplify the trough coming out of the west due to a more intense Alaskan ridge/-EPO, to build ridging ahead of Matthew more aggressively, and to slow the hurricane down over the last 3 days’ worth of runs.
This prolonged and consistent trend for a slower and more amplified central US trough and stronger ridging along the East Coast ahead of Matthew, due to the hurricane moving slower than some models expected and due to the cut off low moving away quicker, is concerning and is likely legitimate, given these trends have been consistent for several runs on almost every model.
The main question now is will the trends stop, reverse, or continue? Given the cut off low moving off the Northeast coast will only move so fast due to the very nature of cut off lows, I do think there’s a limit to how strong ridging ahead of Matthew can get. I think a direct landfall on the east coast of Florida is possible, with the hurricane then bending NE and possibly also directly hitting the Carolinas and possibly getting close to Georgia. I do not foresee a scenario in which Matthew plows deep into Florida as being plausible, due to the cut off low’s weakness in the ridging likely allowing for enough of a northward motion to prevent that…however, significant impacts from a major hurricane are becoming increasingly likely in eastern Florida. The most recent runs of the ensembles all agree on a very close shave for the eastern Florida coast, and it’s important to note that recent model trends in the “key players” haven’t stopped, which again means that a direct hit is at least possible:
As we head towards the weekend, the trough coming out of the western US will approach the eastern US, where Matthew will be waiting to interact with it. There are three possible solutions here:
- Matthew is south of the base of the trough and gets kicked to the northeast, away from land, as the trough moves in
- Matthew is not south of the base of the trough, but the trough is neutrally or positively tilted, and the cyclone gets accelerated to the north/northeast and passes very close to the Mid Atlantic coast and possibly clips eastern New England
- Matthew is not south of the base of the trough, the trough is negatively tilted, and the cyclone gets captured by the trough while accelerating north/northwest and deepening. This is a worst case scenario for this storm for the Mid Atlantic and New England.
The million dollar question at this time of course is, which solution is more likely?
If you believe the European ensembles, Matthew is slow enough and the trough is progressive enough that Matthew is still south of the trough base when it moves east, resulting in a kick northeast and away from land. As you can see from the above probability map from the Monday afternoon Euro ensembles, most members do NOT hook Matthew back towards the Mid Atlantic or New England after the close call for the Southeast. It is worth noting that with a stronger –EPO and perhaps a –NAO that the pattern may still trend more amplified, this is 6 days away.
The GFS ensembles are a little bit quicker with Matthew than the European ensembles, and also are more amplified with the trough. This gives Matthew a better shot at possibly being captured by the trough. With that said, AT THIS TIME, most GFS ensemble members do not capture Matthew and kick it northeast and away from land as the trough approaches.
“Slower” has been the correct solution for Matthew so far, and the GFS ensembles, which are faster, still largely fail to capture Matthew. Given this, I’m leaning towards Matthew moving northeast and away from the coast after impacting the Carolinas, but it is less than a certain call.
Factors to watch for the Mid Atlantic:
- Does –EPO ridging or –NAO ridging intensify enough to amplify the trough more
- Does ridging ahead of Matthew weaken just enough for a quicker track northeast, giving the trough better odds at capturing it.
Regardless of whether or not Matthew directly impacts the Mid Atlantic or New England, a jet streak and cold front ahead of the trough will provide for strong lift as moisture from Matthew gets drawn northward ahead of the front, potentially resulting in heavy rain over the Mid Atlantic and New England. Some drought stricken areas could use the rain.
-Matthew will produce devastating flooding in the Hispaniola and damaging winds in portions of Haiti. A very high death toll is sadly quite possible in Haiti. Significant impacts will also be felt in eastern Cuba.
-Matthew will slowly track over much of the Bahamas as what will likely be a major hurricane.
-The chances for significant impacts to eastern Florida have increased, and a landfall is possible as a major hurricane.
-The chances for significant impacts to coastal Georgia, North Carolina, and South Carolina have increased, and a landfall as a hurricane is possible in the Carolinas.
-A direct impact on the Mid Atlantic or New England still seems unlikely, but trends in Matthew’s speed and the amplitude of the incoming shortwave trough this weekend need to be watched closely.