Oct. 1, 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 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.
With the weekend upon us, 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.
"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 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!
Models have generally trended on a better consensus recently with the sharp turn to the north over the Central Caribbean with movement then near or over Jamaica, Cuba & near or just west of Hispaniola before continuing north into or near the Bahamas to the east of Florida. 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). "Matthew" has slowed & appears to be reaching its crossroads -- the sharp turn to the north by Sat. night/Sunday. The European is now one of the farthest east models while the GFS is generally the farthest west. I am reminded of several instances -- one as recently as one year ago with "Joaquin" & "Isidore" in 2002 (which I flew over in a C-130 with the AFR), when models kept insisting on a turn or a move while reality / the hurricane & the atmosphere had other ideas. It is worth noting that the European "won" the model battle last year with "Joaquin" on an eventual move away from the Bahamas out to sea over the Atlantic. 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 while several other models aim more at Eastern Cuba. 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 earlier this week as typhoon "Megi" went west/northwest through Taiwan Mon. night/early Tue. This (teleconnection) could imply a stronger ridge will evolve over the W. Atlantic in the coming days. If so, "Matthew" may be destined for a more westward (& south) track over the Caribbean. Also -- as I've mentioned several times in this blog -- several forecast models have had a tendency to recurve systems too soon this season & so reality has been farther west. 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 the weekend & studies have indicated that model accuracy can improve by as much as 20%.
So..... IF "Matthew" ends up east of Florida next week....
the primary impacts on Northeast Florida/Southeast Georgia 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. BUT remember it is still early in the forecast on "Matthew" & changes are quite likely.
The band of clouds near & just off the U.S. east coast on the satellite imagery below is being driven by a cold front & strong upper level trough of low pressure (see 2nd image below) with a surface low & upper low stacked over the Ohio Valley. This upper trough will close off & settle over the Eastern/Northeast U.S. over the weekend but gradualy weaken & lift off to the northeast leaving behind a weak, "baggy" trough near the east coast of the U.S. 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 the GFS model seems to follow which is initially reinforced by a weak yet very important upper level trough into the Southeast U.S. early next week which in turn -- according to the GFS model -- keeps "Matthew" to the east of Fl. though with a recent trend more west. The European model seems to have sniffed this alleyway too. 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) & generally the slower model. Both models are just about in lockstep until late in the weekend which looks to be the so-called crossroads for movement of "Matthew". The hurricane has been slowing which was a necessity before we can see a 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 late in the weekend/early next week 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.
The upper level forecast for midday Mon. shows the upper level trough east of the Great Lakes 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. 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 moving into the Eastern U.S. next week could also play a role in "Matthew's" movement.
Monday:
The strong wave -- initially dubbed 97L -- that moved off Africa 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 hundreds of miles northeast of "Matthew". The European model shows some impact from this mid Atlantic tropical wave on softening the Bermuda High which might be one of the reasons the European model is now so far east after hitting the Bahamas.
Zoomed in image of "Matthew" shows heavy rain & wind hammering Aruba & the north coasts of Venezuela & Colombia. There remains decent upper level outflow to the north & northeast while shear is limiting outflow on the west side of the tropical cyclone:
Visible satellite imagery very nicely shows the intense vertical convection near the cneter & over the eastern circulation of "Matthew":
Forecast models - flips will remain possible & adjustments are almost a certainty......
Look at the satellitel 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".......
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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 SW Atlantic/Caribbean & Southern 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. But satellite imagery does show some degredation of the hurricane probably partly due to the shear:
Gulf of Mexico:
East Atlantic:
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.
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Sea surface temps. vs. average:
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