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09-29-2016, 06:32 PM
Post: #21
We have lots of model runs yet to sort this out and for me anyway, not
convinced its just an east coast storm. That north hook is a bit drastic
.... It'll go north eventually looking at the whole set of dynamics,
but far S Fla may have some issues. Just sayin'

Roll me out in the cold rain and snow ...

And brave the storm to come,
For it surely looks like rain.
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09-29-2016, 08:05 PM (This post was last modified: 09-29-2016 08:52 PM by Her-icane.)
Post: #22
[Image: wg8dlm1.GIF]


Quote: Hurricane Matthew Is Born in Caribbean; Uncertainty Reigns in Long-Term Outlook

By:Bob Henson , 10:06 PM GMT on September 29, 2016

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The 13th named storm of the 2016 Atlantic season became Hurricane Matthew at 2:00 pm EDT Thursday. After detecting a small area of hurricane-force winds earlier in the day, an Air Force Hurricane Hunter flight found more consistent evidence of surface winds up to the 75-mph hurricane threshold, thus prompting the upgrade. This is the first Matthew to reach hurricane strength since the name was introduced in 2004, and it’s also the fifth hurricane of the 2016 Atlantic season. Most of this year’s storms have been on the weak side, together producing only about 70% of the usual amount of accumulated cyclone energy for this point in the season. Matthew could boost that percentage considerably over the next week or more.

[Image: matthew-sat-2107Z-9.29.16.jpg]
Figure 1. Satellite image for Matthew as of 5:07 pm EDT Thursday, September 26, 2016.

Fighting and surviving headwinds
Tropical cyclones often weaken or fail to develop in the “hurricane graveyard” of the eastern Caribbean Sea. Trade winds typically accelerate through the region in a way that leads to sinking air and enhanced vertical wind shear. (See details in this 2010 paper from the Bulletin of the American Meteorological Society). Indeed, Matthew has been fighting vertical wind shear of close to 20 knots that was predicted by some but not all models. Early Thursday, Matthew’s low-level center decoupled from its central convection (showers and thunderstorms) and was clearly visible on satellite. A new batch of convection erupted by midday Thursday atop the low-level center, and the old convection has morphed into a banding feature feeding into Matthew. These elements should help sustain and nourish Matthew’s growth. At the same time, Matthew is plowing into fairly dry air at middle levels of the atmosphere, as revealed in visible satellite imagery that shows low-level outflow features to the west of the center. Matthew’s sustained winds remained at 75 mph in the 5 pm EDT update from the National Hurricane Center. Radiometer observations from the midday Hurricane Hunter flight detected peak surface winds of up to 67 knots (77 mph) around 17Z (1:00 pm EDT).

A Tropical Storm Watch is in effect for the southeast Caribbean islands of Bonaire, Curacao, and Aruba as Matthew passes to the north. In addition, a rare Tropical Storm Watch is now in effect for the coast of Colombia, extending from the Venezuala border west to Riohacha. Matthew is not expected to make landfall in South America, but its large circulation could bring gales and heavy rains near the coast.

[Image: shear-18Z-9.29.16.jpg]
Figure 2. Vertical wind shear across the Caribbean as of 18Z (2:00 pm EDT) Thursday, September 29, 2016. Higher shear (unfavorable for tropical cyclones) is shown in red. Matthew has reached and maintained hurricane strength despite wind shear of around 20 knots. The shear may continue for another couple of days as Matthew enters the central Caribbean, but then is predicted to lessen. Image credit: CIMSS/University of Wisconsin/SSEC.

[Image: matthew-modis-sep29.jpg]
Figure 3. MODIS satellite image of Matthew taken at 11:30 am EDT September 29, 2016. Image credit: NASA.

Short-term forecast for Matthew
The outlook for Matthew is fairly straightforward over the next couple of days. Late Wednesday, Matthew was moving due west at 17 mph, and a very gradual, well-predicted bend to a track just south of due west appears to be in progress. Along the way, conditions will favor at least some strengthening, as the atmosphere around Matthew moistens (relative humidity will rise from around 55-60% Wednesday to around 65% by Friday) and wind shear relaxes to around 10 knots by Saturday. There is fairly strong model agreement that Matthew will be positioned in the central Caribbean north of Colombia and south of Hispaniola by Saturday, perhaps as a Category 2 hurricane.

The outlook grows much more complex from this weekend onward. Models continue to agree that an upper low cut off from the jet stream over the eastern U.S. will extend into the Gulf of Mexico by the weekend, helping to urge Matthew northward. One big question is how far west Matthew will get before that sharp right-hand turn occurs. The longitude of the turn will help determine the westward extent of Matthew’s subsequent track, which in turn will shape whether Matthew threatens Cuba, Jamaica, and/or Hispaniola by early next week. The NOAA Gulfstream-IV aircraft that samples the environment around hurricanes is again in service after a multiweek outage, and data from the G-IV flights will be incorporated in model runs starting at 00Z Thursday, which should help nail down Matthew’s track.

Conditions may turn even more favorable for Matthew to intensify from around Saturday to Tuesday as it approaches the Greater Antilles. The official NHC outlook brings Matthew to the high end of Category 2 strength by Monday, when it is forecasted to be approaching eastern Cuba. There is only limited skill in predicting hurricane intensity five days out, and we cannot rule out the possibility that Matthew will intensify even more, or will fail to intensify very much. Rapid intensification is a distinct possibility, given the very large heat content in the northern Caribbean waters. Interests in the Greater Antilles, especially from eastern Cuba to the Dominican Republic, should pay especially close attention to Matthew’s progress. Matthew is a large storm and could lead to torrential rains and life-threatening floods and mudslides near its path in the Greater Antilles.

[Image: matthew-tracking-21Z-9.29.16.jpg]
Figure 4. National Hurricane Center five-day outlook for Matthew as of 5 pm EDT Thursday, September 29, 2016.

Long-range forecast for Matthew
It appears increasingly likely that Matthew will move north from the Caribbean into The Bahamas and avoid the Gulf of Mexico, although residents along the Gulf Coast would be prudent to keep an eye on it. On Wednesday and Wednesday night, the European model included a minority of ensemble members that took Matthew into the Gulf later next week. In its 12Z Thursday run, the European ensemble became somewhat more unified around the idea that Matthew will move north into The Bahamas, then perhaps angle northwest from that point. The 12Z Thursday operational run of the UKMET model tracked along the same general lines as the Euro ensemble. Meanwhile, the GFS model and its ensemble members have been resolute for more than a day in taking Matthew through The Bahamas early next week on a steady northward track, with uncertainty growing as it approaches the Southeast and Mid-Atlantic coast.

Beyond The Bahamas, the GFS and European solutions leave open the possibility that Matthew could approach the U.S. East Coast anywhere from Florida to Maine, but the timing and location of that track remain very uncertain. Steering currents will hinge on the evolution of this weekend’s cut-off low in the eastern U.S. and on a new upper-level low that will be sweeping into the western U.S. It is far to soon to know exactly how these features will evolve. Next week’s upper trough could arrive in time to steer Matthew out to sea late next week, as suggested by the 12Z runs of the GFS and ECMWF operational model. However, any slowdown in that trough’s arrival, or any change in its configuration, could lead to a vastly different solution for Matthew—including a track angling inland. It is quite rare for such a trough to be perfectly predicted a week in advance.

The bottom line: Matthew will pose a significant threat to the Greater Antilles in the 3-to-5-day time frame, and a potential threat to the U.S. East Coast in the 6-to-10-day time frame. Future model runs will allow us to be more specific about the areas that will be most at risk and when that might be. As always, the five-day outlooks from the National Hurricane Center and the associated local bulletins are the place to turn for official guidance.

Jeff Masters will be back with our next update on Matthew by late Friday morning.

Bob Henson

[Image: ensembles-pm-9.29.16-v2.jpg]
Figure 5. Track forecasts from (left) the five European model ensemble members that have performed best with Matthew thus far [gray lines], effective 12Z Thursday, September 29, 2016; and (right) the full 20-member GFS ensemble, effective 18Z Thursday.

[Image: clark14latest.png]
[Image: clarki14latest.png]

[Image: CtkK9LnXgAARqD3.jpg]

30 foot significant wave heights (average of highest 1/3) at buoy north of center of Hurricane Matthew
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09-30-2016, 04:20 AM
Post: #23
500 AM AST FRI SEP 30 2016

There are no data currently available from the inner core of
Matthew, so it is unclear whether the earlier rapid intensification
is continuing. A well-defined elliptical eye is seen in data from
the Curacao radar. However, the latest satellite imagery shows
that the central convection is somewhat asymmetric and that an eye
is yet to form. Satellite intensity estimates are 90 kt from TAFB
and 77 kt from SAB. Based on continuity from the previous advisory
and no improvement in the satellite signature, the initial intensity
is held at a possibly conservative 85 kt. It is notable that the
rapid intensification has occurred despite an ongoing 20 kt of
southwesterly vertical wind shear.

The initial motion is 265/12. There is little change to the track
forecast philosophy from the previous advisory. A low- to
mid-level ridge to the north of Matthew should keep it moving
westward or south of westward for the next 36 hours with some
decrease in forward speed. From 48-120 hours, the ridge is
forecast to weaken and shift eastward as a mid- to upper-level
trough moves into the central and eastern Gulf of Mexico. This
evolution should cause Matthew to turn northwestward and then
northward. There is a significant spread in where the turn will
occur and how fast Matthew will move afterwards. The ECMWF and
UKMET are on the eastern side of the guidance envelope and slower
than the other models, while the GFS and Canadian models are to the
left of the center of the guidance envelope and much faster. The
various consensus models split these differences in both track and
speed, and the new forecast track lies close to them. Overall, the
new track is a little south of the previous track through 48 hours
and a little west of the previous track from 72-120 hours.

The intensity forecast is very problematic. The ongoing shear has
so far done little to keep Matthew from intensifying. Despite
this, the intensity guidance is in unanimous agreement that the
cyclone should weaken from 12-48 hours, most likely due to shear.
From 48-96 hours, the shear is expected to diminish, and during that
time Matthew is expected to intensify until it interacts with land.
The intensity forecast will smooth through what could be some ups
and downs in intensity. First, it assumes that the current
strengthening will continue for another 12-24 hours, with Matthew
reaching major hurricane strength. Then, it keeps the intensity at
100 kt from 24-48 hours, followed by some intensification as the
shear lets up. Weakening due to land interaction is forecast after
72 hours. The intensity forecast lies near the upper edge of the
intensity guidance, but it is less intense than the HWRF model from
72-120 hours.


INIT 30/0900Z 14.0N 69.9W 85 KT 100 MPH
12H 30/1800Z 13.8N 71.2W 95 KT 110 MPH
24H 01/0600Z 13.7N 72.5W 100 KT 115 MPH
36H 01/1800Z 13.9N 73.7W 100 KT 115 MPH
48H 02/0600Z 14.5N 74.8W 100 KT 115 MPH
72H 03/0600Z 17.0N 76.0W 105 KT 120 MPH
96H 04/0600Z 20.5N 76.0W 90 KT 105 MPH...INLAND
120H 05/0600Z 24.5N 76.0W 85 KT 100 MPH...OVER WATER

Forecaster Beven

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09-30-2016, 07:55 AM
Post: #24
Cat 2

LOCATION...13.8N 70.3W

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09-30-2016, 10:28 AM
Post: #25

Let me get this straight... a cat 2, no well defined eye, scattered all over the place and with wind shear?? And he is gonna make a 90 degree turn? IMO this guy is gonna be bad enough to make his own weather! Everyone needs to watch him close.
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09-30-2016, 11:05 AM
Post: #26
Cat 3 now

1100 AM EDT FRI SEP 30 2016

Matthew has continued to intensify this morning. An Air Force
Reserve Hurricane Hunter aircraft recently measured a peak SFMR wind
of 99 kt and a 700-mb wind of 103 kt. Based on these data, the
initial intensity is set to 100 kt for this advisory. The aircraft
reported that the central pressure had fallen to 968 mb, and also
observed a 16 n mi wide eye that is open to the southwest. Water
vapor imagery shows a well-established poleward outflow channel,
with outflow also expanding in the southwest quadrant.

This intensification has occurred despite analyzed southwesterly
shear of around 20 kt. The SHIPS model output shows this shear
continuing for the next 36 hours or so, and as a result, the SHIPS
and LGEM models show Matthew weakening during this time. This
weakening trend is also shown by the HWRF and COAMPS-TC hurricane
models. However, I am reluctant to show a decrease in intensity
given that the environment around the cyclone does not appear to
change much. Some short-term fluctuations in intensity are
certainly possible, but the official forecast remains above much of
the guidance in the short range and keeps the intensity at 100 kt
through 72 hours. Some weakening is shown by days 4 and 5 due to
potential land interaction. Late in the period the NHC forecast is
closest to the HWRF model.

Matthew has been moving west-southwestward during the past few
hours, with an initial motion estimate of 255/10. The cyclone
should continue moving south of due west for the next 12 hours to
the south of a mid-level ridge nosing into the northern Caribbean
Sea. After that, Matthew should gradually turn poleward as the
ridge retreats eastward and a trough moves into the eastern Gulf of
Mexico. There remains a large amount of spread in the guidance,
both along and across track. The ECMWF, ECMWF ensemble mean, and
the UKMET are slower and on the right side of the guidance envelope
at 48 hours and beyond. The GFS, GEFS ensemble mean, HWRF, and
COAMPS-TC are faster and farther to the left. The new NHC track
forecast has been adjusted a little to the south in the first 36
hours due to the initial motion, and lies a little south of the
consensus and close to the GFS at this time range. Beyond that
time, the official forecast is an update of the previous one and
lies a little to the east of the latest multi-model consensus and a
bit to the west of the GFS/ECMWF blend.

It is important to remind users that average NHC track forecast
errors are around 175 miles at day 4 and 230 miles at day 5.
Therefore, it is too soon to rule out possible hurricane impacts
from Matthew in Florida.


INIT 30/1500Z 13.7N 70.8W 100 KT 115 MPH
12H 01/0000Z 13.5N 71.9W 100 KT 115 MPH
24H 01/1200Z 13.5N 73.3W 100 KT 115 MPH
36H 02/0000Z 13.8N 74.3W 100 KT 115 MPH
48H 02/1200Z 14.7N 75.0W 100 KT 115 MPH
72H 03/1200Z 17.5N 76.0W 100 KT 115 MPH
96H 04/1200Z 21.5N 76.0W 90 KT 105 MPH
120H 05/1200Z 25.5N 75.7W 85 KT 100 MPH

Forecaster Brennan

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09-30-2016, 11:21 AM
Post: #27
You got to be kidding me

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09-30-2016, 12:00 PM
Post: #28
968 mb - WOW

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09-30-2016, 04:13 PM
Post: #29
Cat 4 now.

Interesting disco by NHC @ 5:00 PM:

Roll me out in the cold rain and snow ...

And brave the storm to come,
For it surely looks like rain.
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09-30-2016, 04:13 PM
Post: #30
WOW....well that escalated quickly
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