Oct. 2, 2016 — Powerful "Matthew" is squarely over the Caribbean..... anyone with travel plans to the Caribbean should stay up to date on the latest developments & forecasts..... heads-up Puerto Rico, Haiti, Dominican Republic, Cuba, Jamaica..... then the Bahamas & possibly parts of the coastal U.S.
WE'RE JUST A FEW WEEKS PAST THE PEAK MONTH OF THE HURRICANE SEASON... You should always be prepared & aware. First Alert Hurricane Center here. Reminder that flood insurance policies take 30 days to take effect..... & will not be written when/if a named storm is nearby.
Now would be a good time to clear gutters of leaves & pine needles... trim old, overgrown, or dying tree branches & bushes... & clear debris from storm drains on neighborhood streets. Even if "Matthew" stays to the east next week, some heavy rain bands will rotate west from the Atlantic on-&-off Sunday through the middle of the week (not necessarily directly related to "Matthew) along gusty onshore winds courtesy a pretty tight pressure gradient between "Matthew" to the east/southeast of Fl. & high pressure to the north. The GFS model forecast for early Wed. shows strong high pressure near/just east of Maine while "Matthew" makes its move into the Bahamas. Unfortunately this could be a pretty major beating for our beaches.
"Matthew" was upgraded to a hurricane early Thu. afternoon & has gone through a rapid intensification cycle taking the hurricane from a Cat. 1 late Thu. to a Cat. 5 Fri. evening - the first Cat. 5 over the Atlantic Basin since "Felix" in 2007. Even without much land interaction through the weekend, there will likely be intensity fluctuations due to some ocean upwelling below the hurricane + structural changes such as eyewall replacement cycles which usually occur with well developed strong hurricanes. During the replacement cycle, the hurricane usually weakens some but can then sometimes regain its intensity. Further "up the road", there may be enough land interaction with Cuba & possibly Hispaniola to cause some weakening. The satellite image below was at about the time that the NHC upgraded "Matthew" to Cat. 5 status Fri. evening with winds of 160 mph!
Current IR imagery:
So..... IF "Matthew" ends up east of Florida next week which continues to be the "call" for right now....
the primary impacts on Northeast Florida/Southeast Georgia & much of the Florida coast would be at the coast & beaches about Monday through Thursday with a possible peak Tue./Wed.:
-- gusty winds
-- bands of heavy showers
-- rough seas & surf (10'+ waves possible) resulting in the potential for serious beach erosion
-- some coastal flooding.
Impacts inland would be minimal & relegated mostly to periods of rain. BUT remember it is still early in the forecast on "Matthew" & changes are quite likely & could greatly change impacts -- both at the coast/beaches & inland.
"Matthew" has started its much anticipated turn to the northwest but only very slowly which but should eventually straighten out to a more northerly track. Models have generally trended on a better consensus recently with the sharp turn to the north over the Central Caribbean with movement to a little east of Jamaica (could spare the island the worst), to near the east edge of Cuba & near or just west of Hispaniola before continuing north into or near the Bahamas to the east of Florida through the middle & end of the week. However, there are significant differences on when the turn north will occur & then how fast the hurricane moves north with at least a bit of a stairstep northward (alternating N/NE & N/NW) alternating depending on upper level troughing to the west & northwest & the Bermuda high to the north & east. "Matthew" appears to have reached the "fork in the road" with its turn more northwest. The next couple of days will be pivotal & will likely show us which model(s) to lean toward as the European shows a hit on Haiti/Dominican Republic but has shifted slightly west while several other models aim more at Eastern Cuba OR right between the two islands. Virtually all models then show a move into the Bahamas in one form or another. BUT remember: forecast models are just that - MODELS! I've been mentioning this week that we MIGHT be able to take a hint from what went on over the W. Pacific last week as typhoon "Megi" went west/northwest through Taiwan last Mon. night/early Tue. This (teleconnection) could imply a stronger ridge will evolve over the W. Atlantic in the coming days. Now typhoon "Chaba" will recurve over the far W. Pacific moving over or near Japan by midweek. This could imply -- & forecast models are indicating such -- more troughing developing near the U.S. east coast but not until next weekend which would have implications for the long range movement of "Matthew" & whether or not the hurricane gets captured & to what extent. G-IV air research missions conducted the last couple of days did allow realtime atmospheric data to be ingested into the model data analysis which -- in theory -- could lead to better forecasts, but I remain steadfast that the plane data has to be a constant input in each & every model run for that data to offer consistency & therefore to be of much value. But such an undertaking is expensive. It does appear that G-IV missions will at least be pretty constant through into next week. Studies have indicated that model accuracy can improve by as much as 20% thanks to the G-IV missions.
Check out the noticeable differences for early Fri. between the GFS (green lines/circled L) vs. the European model (yellow line/L)..... though both are still a good deal east of Florida.
The band of clouds near the U.S. east coast on the satellite imagery below is being driven by a stalling front & strong upper level trough of low pressure (see 2nd image below) that is slowly filling (weakening) with a surface low & upper low stacked over the Ohio Valley. This upper trough will lift off to the northeast leaving behind a weak, "baggy" trough near the east coast of the U.S. that intially extends south into the Gulf of Mexico which should help with the more northward movement in the short term. This upper level pattern will be the key for "Matthew". A clear alleyway of lower pressure exists right now over the W. Atlantic which is what many of the models seem to follow which is reinforced by the weak yet very important upper level trough into the Southeast U.S. & Gulf. The European model seems to have sniffed this alleyway too but is -- overall -- much slower, especially in the long term. The European ensemble (combination of a number of model runs to show an average) still shows plenty of spread west & east but has recently started to focus more east (but still over the Bahamas by midweek). Both models are just about in lockstep until late in the early to midweek which is related to the upper level troughing over the U.S. vs. upper level ridging over the Atlantic. The hurricane has been slowing which was a necessity before we can see the full turn to the north. Most of the other global forecast models are somewhere in between the GFS & European models but are pretty clustered near Cuba/Hispaniola early to midweek then northward to the Bahamas but staying east of Florida. Any land interaction (S. America, Cuba or Hispaniola) complicates the intensity forecast. Word of caution here: weakening over any landmasses could result in a more shallow system for a time that would turn more northwest - just another wildcard to consider. I want to emphasize the importance of the Bermuda High -- its location & intensity as to how "Matthew" will behave -- movement north or northwest & its speed of movement.
The upper level forecast for midday Tue. shows the upper level trough over New England weakening & lifting off to the northeast with the Bermuda High firmly entrenched over the Central Atlantic creating a "soft spot" through the far Western Atlantic... but there are signs of the Bermuda Highs trying to build west. As I've tried to highlight -- any strengthening of the Bermuda High pushes "Matthew" more west is something to be cognizant of even though the early indications are the alleyway stays open. A second strong upper level trough -- see 2nd image below for Fri. -- moving into the Central U.S. late in the week could also play a role in "Matthew's" movement but not until the long range (next weekend or so).
Tuesday:
Friday:
The strong wave -- initially dubbed 97L -- that moved off Africa more than a week ago became "Matthew" Wed. & has steadily strengthened, sometimes quickly despite a good deal of shear out of the southwest. Caribbean tropical cyclones do have a tendency to thrive in late Sept. - Oct. which adds even more confidence to the forecast of a stronger hurricane. A couple more waves trail "Matthew", & we could see another storm or two pop over the Central &/or Eastern Atlantic within the next week or so. In fact, an area of "disturbed" weather/tropical wave is over the Central Atlantic well east/northeast of "Matthew" followed by a 2nd disturbance/wave over the Eastern Atlantic.
Zoomed in image of "Matthew" shows heavy rain & wind still lashing the north coasts of Venezuela & Colombia. There remains decent upper level outflow to the north & northeast while shear continues limiting outflow on the west side of the tropical cyclone. Another very interesting & persistent feature has been bursts of strong convection to the east of the core of "Matthew". This might be tied to some mid & upper level diffluence (of winds). The tendency has been for these bands to eventually wrap around the hurricane followed by lowering of the central pressure + a tightening of the eye. Pretty fascinating, really.
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Visible satellite imagery very nicely shows the intense vertical convection near the cneter & over the eastern circulation of "Matthew":
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Forecast models - flips will remain possible & adjustments are almost a certainty......
Look at the satellite loop below & the combination of an upper low & tropical wave over the Central Atlantic - question is will this weaken the Bermuda High??? If so, farther east once into the Bahamas could be the track for "Matthew" but a bend back -- at least somewhat -- to the northwest could then occur.......
Image below shows the oceanic heat content. Yellow, orange & red indicates higher heat content which can give tropical cyclones added "energy". Pretty impressive over the Caribbean, SW Atlantic & Western Gulf.....
Water vapor imagery below shows plenty of moisture pooling over the Western Atlantic/Caribbean & Central/Eastern Gulf of Mexico....
The wind shear (red lines represent strongest shear) analysis shows the persistent & significant wind shear in the vicinity of "Matthew" across a good part of the Central/Northern Caribbean with speeds of 30-50 mph! .... at which "Matthew" has seemed to scoff at so far. It seems possible that the upper level trough over the Gulf of Mexico might be helping to ventilate "Matthew" thereby helping to compensate for the strong shear (just speculation on my part!).
Gulf of Mexico:
East Atlantic with westward moving wave at about 13 degrees N:
Lots of warm water to help "feed" tropical cyclones. Water temps. of 28 degrees Celsius equates to 82 degrees Fahrenheit. Tropical cyclones generally need at least 80 degree water to thrive.
Sea surface temps. vs. average:
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