"Talking the Tropics With Mike": Rapidly strengthening "Matthew" - Sept. 30th

Sept. 30, 2016 — "Matthew" is over the Central & Southern 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.

"Matthew" was upgraded to a hurricane early Thu. afternoon & then went through a rapid intensification cycle Thu. night/early Fri. reaching "major" status - Cat. 3 by late Fri. morning. 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" slows down through the weekend & reaches a crossroads -- the sharp turn to the north by Sat. night/Sunday.  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.  Afterall: 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 late Thu./Thu. night 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 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 evident 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 later in the period (middle of next week) which could be a problem for the Carolina's.  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).  Both models are just about in lockstep until the weekend which looks to be the so-called crossroads for movement of "Matthew" & the turn north though the forward speed has got to slow before there can be the hairpin turn.  A strengthening hurricane like "Matthew" is sort of like a snowball rolling down a hill gaining momentum.  Until that momentum slows, "Matthew" will have a hard time turning on a dime.  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 late Fri. shows the trough over the Eastern U.S..... the 2nd upper level chart is for midday Mon. & shows the upper level trough 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.

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 have certainly trended east recently (after the turn north) but model flip-flops will remain possible & adjustments are almost a certainty......

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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.....

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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 southwest 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:

Gulf of Mexico:

East Atlantic where tropical waves continue to march westward.  We're nearing what is typically the end of the "Cape Verde season".... this is where "Matthew" originated - a classic deep tropical cyclone:

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:

Meanwhile.... Hurricane "Joaquin" was born this week a year ago on Sept. 27th, 2015.  The infamous storm will be remembered for the sinking of the El Faro (it was later determined that the ship's captain was using old forecast info. [at least 24 hours old] for "Joaquin" which likely proved to be fatal since "Joaquin" was so rapidly intensifying while also shifting south & west) & the tropical cyclone's forecasting headaches.  The tropical depression on the 27th became a tropical storm on the 28th... the El Faro left port in Jacksonville on the 29th... "Joaquin" became a hurricane on the 30th going through a rapid intensification cycle whereby it became a Cat. 3+ later in the day in less than 24 hours... the El Faro was sunk near the Bahamas on Oct. 1 when "Joaquin" was a Cat. 4... peak intensity -- close to Cat. 5 -- was on Oct. 2 as "Joaquin" moved northeast away from the battered Bahamas.

Below I've reprinted my "Buresh Blog" & Tracking the Tropics With Mike" info. on "Joaquin" from the first week of Oct., 2015:

A quick review: "Joaquin" went hurricane early Wednesday undergoing a rapid intensification cycle that saw the storm go from a tropical storm to Cat. 3 in a little more than 24 hours then to a Cat. 4 early Thu. afternoon.   The hurricane briefly dropped to a Cat. 3 Friday afternoon - early Sat. before going through yet another "growth spurt" Saturday taking the violent hurricane to near Cat. 5 status as hurricane hunter aircraft found winds near 155 mph & falling pressure.  That peak intensity did not last long & there has been a steady weakening since due to cooler water temps. & increasing shear.  The tropical cyclone passed Bermuda to the west as Cat. 2 dropping to Cat. 1 in the process.  Dry air is being drawn into the storm by the strong circulation with much of the more intense convection over the northern & northeast part of the circulation, but the hurricane has remained remarkably well intact north & northeast of Bermuda.  

The sometimes more reliable European model in the past was an outlier to the west -- far to the west -- on "Joaquin".  So the European model wins this forecast battle, hands down.  The European model was one of the first models to take an intense hurricane initially southwest & deep into the Bahamas -- where it went.  Most of the hurricane forecast models -- HWRF & GFDL -- hooked the hurricane rather abruptly west/northwest into the U.S.  The problem is these models have bordered on being horrible the past few years.... & certainly this season.  In fact, the NAM (North American Model) -- which is a mesoscale (small) scale model not necessarily intended for tropical cyclones but has been tweaked on & off the last few years to try to do better on "in-close" tropical cyclones -- was shutting down last week during its forecast cycle unable to finish the job.  One of theories put forth by modelers is that the NAM was not handling the environment well (namely anomalously warm water) near "Joaquin".  Will be an interesting offseason for tropical cyclone numerical modelers - time to get busy!

"Thanks" to national & even some local media outlets, it has to be pointed out that THERE HAVE NOT BEEN & WILL NOT BE DIRECT U.S. IMPACTS FROM "JOAQUIN".  But there will still be some very rough & dangerous weather for areas from Eastern Ga. through the Carolina's to near Chesapeake Bay where there has been flooding, gusty winds, very rough seas & surf & a high rip current risk.  But these weather elements were a combination of a stalled front & the strong upper level disturbance vs. a any kind of hurricane input.  It's true there have been some added surface winds courtesy the pressure gradient between hurricane "Joaquin" & high pressure to the north, but the tropical cyclone's circulation was way, way, way, way to the east.

It's likely that "Joaquin" will remembered for several outstanding "traits", & I would think the name will probably be retired late winter/early spring (the annual list of names returns every 6 years). For blow by blow details with regards to forecasting "Joaquin" last week, you can check "Talking the Tropics With Mike".

(1) the forecast model mayhem

(2) the first Oct. Cat. 4 hurricane to directly hit the Bahamas since 1866

(3) the sinking of the large cargo ship - El Faro.  There have been a lot of questions regarding why El Faro ventured into an intensifying hurricane.  It's possible there was not much the captain could do because of mechanical failure, but it will be up to a future investigation to determine if mechanical difficulty was indeed the beginning of the end for the ship.  Initial forecasts certainly were of little value BUT rapidly changed & were updated such that the crew would have had more than enough time to steer clear of the mighty storm.  Below you'll find a series of track/intensity forecasts + satellite images:

The forecast below was from early Tue. - about when El Faro left port from Jacksonville.  Looking at this forecast, the captain would have little to be concerned about if simply taken for face value.

But the forecast changed drastically in just 12 hours.  Below is the forecast from Tue. evening -- a hurricane dipping more southwest toward the Bahamas.  Crooked Island (where El Faro disappeared) is in the "cone of uncertainty" as is most of the Bahamas.

The early Wed. forecast takes "Joaquin" to Cat. 2.... BUT still not far enough southwest.  In fact, there's been a slight adjustment to the east.

Late Wednesday (a forecast a bit farther southwest)......

Late Wed. evening.... taking the storm to Cat. 3 + closer to the Bahamas......

The forecast models were in disarray - this is from Wed. evening.... through Mon. evening.  We know now that this simply wasn't even close (I believe the models were greatly confused by an incoming area of strong upper level low pressure & therefore the models developed too much low pressure near the east coast which the models mistook for "Joaquin".  In the end, the 2 systems stayed apart -- by a long ways.  Only the European global forecast model picked up on this possibility Wed./Thu. of last week, & it wasn't until Thu./Fri. that most of the rest of the models started to catch on.

IR satellite imagery below at 7:15am, Thu. Oct. 1 - the approximate time of the last transmission from El Faro.  Strong high end Cat. 3 "Joaquin's" eye was just north of Crooked Island which means the ship would have been very near the violent eyewall where winds were 120+ mph & seas were reported to be 40+ feet!

The IR image below is 24 hours later -- early Fri. (7:15am EDT) -- when search & rescue was underway for the El Faro.  The eye of now Cat. 4 "Joaquin" is only about 40-50 miles northwest of Crooked Island & the search area was besieged by the more violent southeast quadrant of the powerful hurricane.

Thursday evening (Oct. 1) storm analysis -- immediate northwest of Crooked Island......

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