ATL: HARVEY - Post-Tropical - Discussion

[ROCK]

model ping pong continues. GFS now keeps the system alive

D did you just mention the Model that shall not be named in 2017?

[ROCK]

model ping pong continues. GFS now keeps the system alive

Look at that upper trough dropping S interacting with the TUTT. The models are clearly struggling. Need the NOAA Global Hawk missions and additional NWS Forecast Office special balloon launches next week.

agree with Srain on this....that would help. The potential is there. Also I take notice of the NAM even if 84hrs out for upstream synoptics. that's just me though...

[p1nheadlarry]

Getting a little feisty here at sunset

Dealing with some dry air right now it appears.

BTW, that is a great avatar.

[chaser1]

With the latest discussion laying everything out, i'm gonna go out on a limb here. Assuming that Harvey will have at least maintained its identity as a closed system, I believe that the storm will undergo some significant strengthening at its crossing 70W and within the 24-36 hr. period. I'll further guess that Belize or Yucatan will have to brace for a Cat. 2 or 3 hurricane. As I see it, the cut-off centered over the Florida Straits will continue to not only move westward but more importantly will gain latitude as well. I think that the shear impacting Harvey now will lesson in about 24 hours as the storm moves a little further west and that we'll see a broader upper anticyclonic flow begin to bridge south and over the Central Caribbean. Obviously no models seems to think that and NHC seems to be hinting towards possibly better upper conditions but further out than that. Hmmm, maybe I wont quite bet the farm on it LOL; better I keep it to a 6-pack of beer!

Very bold. For the sake of your prediction--good luck!

LOL, thanks. Fortunately for the good folks in Texas, I'm not anticipating the need to quit my day job. Besides if I was REALLY sure about my somewhat educated hunch, I'd throw down more than a six pack of Coors Light

[Alyono]

looks like the shear has increased further. Think this needs to be moving in excess of 30 kts to reduce the shear

[p1nheadlarry]

looks like the shear has increased further. Think this needs to be moving in excess of 30 kts to reduce the shear

Wouldn't that be a little troublesome for the vorticity staying alligned through the midlevels?

[Alyono]

looks like the shear has increased further. Think this needs to be moving in excess of 30 kts to reduce the shear

Wouldn't that be a little troublesome for the vorticity staying alligned through the midlevels?

would be easier to stay aligned if it was moving at the same speed as the upper winds. That would mean the flow at all levels was the same, which would reduce the shear

[p1nheadlarry]

looks like the shear has increased further. Think this needs to be moving in excess of 30 kts to reduce the shear

Wouldn't that be a little troublesome for the vorticity staying alligned through the midlevels?

would be easier to stay aligned if it was moving at the same speed as the upper winds. That would mean the flow at all levels was the same, which would reduce the shear

I guess that makes sense in a mathematical sense. Not yet a met but I at least have a physics background.

[Hammy]

I'm starting to think Harvey dissipates in about 24-36 hours and regenerates later on--starting to remind me of Chantal in 2001 (one of the years I have as possible analog) and interestingly the Euro has been hinting at a similar track.

[Alyono]

I'm starting to think Harvey dissipates in about 24-36 hours and regenerates later on--starting to remind me of Chantal in 2001 (one of the years I have as possible analog) and interestingly the Euro has been hinting at a similar track.

it has probably already dissipated. Does not have the signature of a tropical cyclone on satellite any longer

[cycloneye]

Tropical Storm Harvey Discussion Number 7
NWS National Hurricane Center Miami FL AL092017
1100 PM AST Fri Aug 18 2017

Microwave and conventional geostationary satellite images indicate
that Harvey's center is still displaced to the east of a persistent
cluster of deep convection due to about 15 kt of northeasterly
shear. With no notable changes in the cyclone's structure since
the last advisory, the maximum wind estimate remains 35 kt, which
is in line with the latest Dvorak CI numbers.

Recent microwave fixes suggest that Harvey's center may have slowed
down or wobbled northward temporarily, and the 12-hour motion
estimate is a slightly slower 275/16 kt. A low- to mid-level ridge
extending across the western Atlantic should keep Harvey on a swift
westward course across the Caribbean Sea for the next 48 hours.
Once Harvey moves into the northwestern Caribbean Sea by 72 hours,
it will reach the western edge of the ridge, and it will likely
slow down and gain some latitude due to a cut-off low over the
northwestern Gulf of Mexico. Although the track guidance envelope
has shifted slightly northward on this cycle, especially around the
72-hour period, there are no significant changes from six hours ago.

Northeasterly or northerly shear is forecast to continue for the
next 36 hours or so, which should prevent significant strengthening
while Harvey moves westward across the eastern and central
Caribbean Sea. By 48 hours, the vertical shear over the cyclone
drops drastically, but the system's fast motion could still
limit the amount of intensification that will occur. The best
opportunity for strengthening would likely be around day 3 when
Harvey begins to slow down as it approaches Belize and the Yucatan
Peninsula. The updated NHC intensity forecast is the same as the
previous one during the first 48 hours, and it was nudged a little
lower at 72 hours to fall closer to the HFIP Corrected Consensus
(HCCA) model and the ICON intensity consensus. A lot of
uncertainty remains, however, since models like SHIPS and HWRF
bring Harvey near or to hurricane intensity before it reaches land
while the GFS and ECMWF continue to weaken the circulation while it
moves across the Caribbean Sea.

FORECAST POSITIONS AND MAX WINDS

INIT 19/0300Z 13.7N 64.1W 35 KT 40 MPH
12H 19/1200Z 14.0N 66.8W 35 KT 40 MPH
24H 20/0000Z 14.3N 70.4W 40 KT 45 MPH
36H 20/1200Z 14.5N 74.3W 40 KT 45 MPH
48H 21/0000Z 14.8N 78.1W 45 KT 50 MPH
72H 22/0000Z 16.5N 84.7W 55 KT 65 MPH
96H 23/0000Z 18.0N 89.5W 45 KT 50 MPH...INLAND
120H 24/0000Z 19.0N 92.5W 40 KT 45 MPH...OVER WATER

$$
Forecaster Berg

[storm_in_a_teacup]

Shoot, we haven't had a real threat since 1980 with Allen. I sure hope it doesn't form up like some are saying, I like my A/C and running water. I don't want to go to SA and get a hotel, my salt tank will die. Hopefully it'll just be a sheared storm with lots of beneficial rain. After reading all the posts on Storm2K of post hurricane strikes over the years has me a bit worried now, especially all the stories from Florida and Louisiana.

Hurricane Allen https://en.wikipedia.org/wiki/Hurricane_Allen#/media/File:Allen_1980_track.png

If your in Texas this definitely needs to be watched ...

You have a saltwater fish tank? What species do you have? ...Okay that's kinda off topic but it caught my interest
(FYI Marine battery + livewell aerator saved my fish in Ike)

[Kazmit]

NHC cone nudged a little more northward...

[latitude_20]

With the latest discussion laying everything out, i'm gonna go out on a limb here. Assuming that Harvey will have at least maintained its identity as a closed system, I believe that the storm will undergo some significant strengthening at its crossing 70W and within the 24-36 hr. period. I'll further guess that Belize or Yucatan will have to brace for a Cat. 2 or 3 hurricane. As I see it, the cut-off centered over the Florida Straits will continue to not only move westward but more importantly will gain latitude as well. I think that the shear impacting Harvey now will lesson in about 24 hours as the storm moves a little further west and that we'll see a broader upper anticyclonic flow begin to bridge south and over the Central Caribbean. Obviously no models seems to think that and NHC seems to be hinting towards possibly better upper conditions but further out than that. Hmmm, maybe I wont quite bet the farm on it LOL; better I keep it to a 6-pack of beer!

Very bold. For the sake of your prediction--good luck!

LOL, thanks. Fortunately for the good folks in Texas, I'm not anticipating the need to quit my day job. Besides if I was REALLY sure about my somewhat educated hunch, I'd throw down more than a six pack of Coors Light

Hey chaser, Tulum, Mexico here (by way of Texas), I doubled down on your hunch this afternoon and topped off my preps. Neighbors think I'm being alarmist. One guy says, "Bah, I lived in FLA for years, no worries!"

I'm not running around wringing my hands and screaming "ONOZ!!!", just want to prepare for a distinct possibility. No storm, no problem, the food will keep and we'll eat it eventually and replace it if need be.

The NHC is admittedly being very soft on their forecast. When they say "low confidence", well, that's just a very professional way of saying, "We don't know what will happen after thus and such..." lol. So yeah, better safe than sorry.

Lost power for 18 hours when Frank made landfall. About two days ago, my girl and I began making preps for at least a 7 day power outage in the event of a Cat 1-2 landfall in our area.

[hd44]

Looking a little better tonight to me.

[stormreader]

Harvey expanding its influence. Larger looking storm.

[cycloneye]

Tropical Storm Harvey Discussion Number 8
NWS National Hurricane Center Miami FL AL092017
500 AM AST Sat Aug 19 2017

GOES-16 shortwave infrared imagery shows the partially exposed
center of Harvey on the eastern edge of a large area of deep
convection. While the center is closer to the convection than a few
hours ago, cirrus clouds be clearly seen moving from northeast to
southwest across the system; an indication of the persistent shear.
Satellite estimates suggest the maximum winds of Harvey remain 35
kt.

The storm has picked up some forward speed with a recent motion
estimate of 275/18. A low- to mid-level ridge extending across the
western Atlantic should keep Harvey on a fast westward course across
the Caribbean Sea for the next 48 hours. Thereafter, the ridge
weakens across the Gulf of Mexico due to a strong mid/upper-level
low currently seen there on water vapor images. This steering flow
change should cause Harvey to slow down and turn a little more to
the west-northwest in the northwestern Caribbean Sea, with an even
slower motion forecast for Harvey in the Bay of Campeche. Model
guidance is in fairly good agreement on this scenario, and no
significant changes were made to the previous forecast.

Harvey should be moving into a more conducive environment for
strengthening early next week since the strong northeasterly shear
that has been affecting the cyclone is forecast by almost all of the
guidance to weaken within about 24 hours. In a few days, most of
the global models show a favorable upper-level environment for
intensification, and Harvey could be near hurricane strength between
the 72 hour forecast period and landfall. There has been little
change to the guidance so the new intensity forecast is similar to
the previous one, close to the model consensus. However, with
a weak storm moving so quickly across the central Caribbean, one
always has to be careful of the system opening up into a wave. This
is a plausible alternative scenario still suggested by the GFS and
ECMWF models.


FORECAST POSITIONS AND MAX WINDS

INIT 19/0900Z 13.8N 65.9W 35 KT 40 MPH
12H 19/1800Z 14.0N 68.7W 35 KT 40 MPH
24H 20/0600Z 14.3N 72.7W 40 KT 45 MPH
36H 20/1800Z 14.6N 76.7W 45 KT 50 MPH
48H 21/0600Z 15.2N 80.1W 50 KT 60 MPH
72H 22/0600Z 17.0N 86.5W 55 KT 65 MPH
96H 23/0600Z 18.3N 90.5W 35 KT 40 MPH...INLAND
120H 24/0600Z 19.3N 93.0W 40 KT 45 MPH...OVER WATER

$$
Forecaster Blake

[Thetxhurricanemaster]

Recon heading in again this will help the global models alot because the GFS and EURO don't bring this too far North because they predict it opens up which I think is unlikely

[HURAKAN]

nice microwave pass

[Thetxhurricanemaster]

nice microwave pass

It's definitely looking better this could be a 50MPH tropical storment maybe 45