ATL: ISAAC - Post-Tropical - Discussion

Moderator: S2k Moderators

Message
Author
AutoPenalti
Category 5
Category 5
Posts: 3946
Age: 27
Joined: Mon Aug 17, 2015 4:16 pm
Location: Ft. Lauderdale, Florida

Re: ATL: ISAAC - Tropical Depression - Discussion

#721 Postby AutoPenalti » Fri Sep 14, 2018 3:35 pm

LLC is really weak. It's pooping out convection that doesn't seem to have that swirl to it.
0 likes   
The posts in this forum are NOT official forecasts and should not be used as such. They are just the opinion of the poster and may or may not be backed by sound meteorological data. They are NOT endorsed by any professional institution or STORM2K. For official information, please refer to products from the NHC and NWS.


Model Runs Cheat Sheet:
GFS (5:30 AM/PM, 11:30 AM/PM)
HWRF, GFDL, UKMET, NAVGEM (6:30-8:00 AM/PM, 12:30-2:00 AM/PM)
ECMWF (1:45 AM/PM)

TCVN
is a weighted averaged

User avatar
Buck
Category 5
Category 5
Posts: 1128
Joined: Fri Sep 10, 2004 12:04 pm
Location: Atlanta, GA

Re: ATL: ISAAC - Tropical Depression - Discussion

#722 Postby Buck » Fri Sep 14, 2018 3:41 pm

Yeah, no wonder models are everywhere/nowhere with this... it's practically nothing at the moment and anything can happen in the Western Caribbean down the road. Not gonna be surprised if a 2.0 happens.
0 likes   

AutoPenalti
Category 5
Category 5
Posts: 3946
Age: 27
Joined: Mon Aug 17, 2015 4:16 pm
Location: Ft. Lauderdale, Florida

Re: ATL: ISAAC - Tropical Depression - Discussion

#723 Postby AutoPenalti » Fri Sep 14, 2018 3:51 pm

Although, if my eyes aren't playing tricks on me, the last few frames seem to show some sort of banding occuring near the center.

Image
Image
Last edited by AutoPenalti on Fri Sep 14, 2018 3:55 pm, edited 1 time in total.
0 likes   
The posts in this forum are NOT official forecasts and should not be used as such. They are just the opinion of the poster and may or may not be backed by sound meteorological data. They are NOT endorsed by any professional institution or STORM2K. For official information, please refer to products from the NHC and NWS.


Model Runs Cheat Sheet:
GFS (5:30 AM/PM, 11:30 AM/PM)
HWRF, GFDL, UKMET, NAVGEM (6:30-8:00 AM/PM, 12:30-2:00 AM/PM)
ECMWF (1:45 AM/PM)

TCVN
is a weighted averaged

User avatar
cycloneye
Admin
Admin
Posts: 138885
Age: 67
Joined: Thu Oct 10, 2002 10:54 am
Location: San Juan, Puerto Rico

Re: ATL: ISAAC - Advisories

#724 Postby cycloneye » Fri Sep 14, 2018 3:52 pm

BULLETIN
Tropical Storm Isaac Advisory Number 29
NWS National Hurricane Center Miami FL AL092018
500 PM AST Fri Sep 14 2018

...ISAAC BECOMES A TROPICAL STORM AGAIN BUT ITS FUTURE IS UNCLEAR...


SUMMARY OF 500 PM AST...2100 UTC...INFORMATION
----------------------------------------------
LOCATION...15.3N 68.2W
ABOUT 250 MI...400 KM SSE OF SANTO DOMINGO DOMINICAN REPUBLIC
ABOUT 600 MI...965 KM ESE OF KINGSTON JAMAICA
MAXIMUM SUSTAINED WINDS...40 MPH...65 KM/H
PRESENT MOVEMENT...W OR 275 DEGREES AT 14 MPH...22 KM/H
MINIMUM CENTRAL PRESSURE...1002 MB...29.59 INCHES


WATCHES AND WARNINGS
--------------------
There are no coastal watches or warnings in effect.

Interests in Jamaica should monitor the progress of Isaac.


DISCUSSION AND OUTLOOK
----------------------
At 500 PM AST (2100 UTC), the center of Tropical Storm Isaac was
located near latitude 15.3 North, longitude 68.2 West. Isaac is
moving toward the west near 14 mph (22 km/h), and this general
motion with some decrease in forward speed is anticipated over the
next couple of days with a turn to the west-northwest possible by
late Sunday. On the forecast track, Isaac will move over the
eastern and central Caribbean Sea during the next few days, and be
near or south of Jamaica early next week.

NOAA Hurricane Hunter data indicate that maximum sustained winds
have increased to near 40 mph (65 km/h) with higher gusts.
Little change in strength is forecast during the next 36 hours.
Isaac is forecast to become a tropical depression on Sunday and
degenerate into a wave on Monday. However this is an uncertain
prediction.

Tropical-storm-force winds extend outward up to 45 miles (75 km)
from the center.

The estimated minimum central pressure from dropsonde data is 1002
mb (29.59 inches).


HAZARDS AFFECTING LAND
----------------------
RAINFALL: Isaac is expected to produce additional rainfall of 2 to
3 inches with isolated maximum totals of up to 5 inches across
southeast Puerto Rico. Rainfall totals of 1 to 2 inches with
maximum amounts of 3 inches are possible across the remainder of
Puerto Rico, the Virgin Islands, the Leeward Islands and the
northern Windward Islands. Rainfall totals of 2 to 3 inches with
isolated maximum amounts of 4 inches are possible across the south-
central portion of the Dominican Republic, southwest Haiti and most
of Jamaica except for the eastern portion of Jamaica where rainfall
totals of 2 to 4 inches and maximum amounts of 6 inches are
possible. This rainfall may cause life-threatening flash floods.


NEXT ADVISORY
-------------
Next complete advisory at 1100 PM AST.

$$
Forecaster Blake



Tropical Storm Isaac Discussion Number 29
NWS National Hurricane Center Miami FL AL092018
500 PM AST Fri Sep 14 2018

It has been a very interesting flight of the NOAA Hurricane Hunter
aircraft this afternoon. Dropsonde and SFMR data indicate that the
maximum winds are around 35 kt again, and the pressure has fallen
to about 1002 mb. However, the system is tilted southward with
vertical height due to northerly shear, and scatterometer and
Hurricane Hunter tail-Doppler radar data indicate the system is
elongated from northeast to southwest, albeit closed. Note that the
plane was unable to sample the southwestern quadrant well because of
strong convection and intense lightning, so the flight-level winds
showing no circulation were unrepresentative.

The intensity forecast hasn't gotten any easier with Isaac.
Vertical shear is expected to decrease a bit more, which might
diminish the effects of dry air seen on water vapor images around
the cyclone. However, the GFS and ECMWF continue to insist that
Isaac will degenerate into a wave within the next 2 or 3 days, which
is almost unanimously supported by their respective ensemble
members. This is the solution that the official forecast follows.
It should be noted that none of the global models show pressures
this low now with Isaac, except the UKMET, and that model is the one
that holds onto the circulation the longest. The reality of the
situation is that the long-term future of Isaac is cloudy, and the
best advice is just to follow NHC advisories every 6 hours to see
if we gain any confidence.

Isaac is moving westward at about 12 kt. A ridge over the
southwestern Atlantic should steer the cyclone westward over the
weekend then west-northwestward early next week as Isaac reaches a
weaker portion of the ridge. Just like yesterday, a stronger system
would likely turn more to the west-northwest earlier, moving
closer to Jamaica. Since the system is forecast to be weaker, the
forecast lies on the westward and faster side of the guidance, and
should also be considered low confidence since it depends on the
intensity. Interests in Jamaica should monitor the progress of the
Isaac.


FORECAST POSITIONS AND MAX WINDS

INIT 14/2100Z 15.3N 68.2W 35 KT 40 MPH
12H 15/0600Z 15.4N 70.1W 35 KT 40 MPH
24H 15/1800Z 15.4N 72.2W 35 KT 40 MPH
36H 16/0600Z 15.7N 74.2W 35 KT 40 MPH
48H 16/1800Z 16.2N 76.3W 30 KT 35 MPH
72H 17/1800Z 17.5N 80.0W 25 KT 30 MPH
96H 18/1800Z...DISSIPATED

$$
Forecaster Blake
0 likes   
Visit the Caribbean-Central America Weather Thread where you can find at first post web cams,radars
and observations from Caribbean basin members Click Here

User avatar
cycloneye
Admin
Admin
Posts: 138885
Age: 67
Joined: Thu Oct 10, 2002 10:54 am
Location: San Juan, Puerto Rico

Re: ATL: ISAAC - Tropical Storm - Discussion

#725 Postby cycloneye » Fri Sep 14, 2018 3:54 pm

...ISAAC BECOMES A TROPICAL STORM AGAIN BUT ITS FUTURE IS UNCLEAR...


SUMMARY OF 500 PM AST...2100 UTC...INFORMATION
----------------------------------------------
LOCATION...15.3N 68.2W
ABOUT 250 MI...400 KM SSE OF SANTO DOMINGO DOMINICAN REPUBLIC
ABOUT 600 MI...965 KM ESE OF KINGSTON JAMAICA
MAXIMUM SUSTAINED WINDS...40 MPH...65 KM/H
PRESENT MOVEMENT...W OR 275 DEGREES AT 14 MPH...22 KM/H
MINIMUM CENTRAL PRESSURE...1002 MB...29.59 INCHES
0 likes   
Visit the Caribbean-Central America Weather Thread where you can find at first post web cams,radars
and observations from Caribbean basin members Click Here

User avatar
meriland29
Category 2
Category 2
Posts: 770
Joined: Thu Aug 03, 2017 11:05 am

Re: ATL: ISAAC - Tropical Storm - Discussion

#726 Postby meriland29 » Fri Sep 14, 2018 3:59 pm

What? A TS again after so close to looking like a wave as of recent. ...well Ill be dipped...
0 likes   

User avatar
HurricaneBelle
S2K Supporter
S2K Supporter
Posts: 974
Joined: Sun Aug 27, 2006 6:12 pm
Location: Clearwater, FL

Re: ATL: ISAAC - Tropical Storm - Discussion

#727 Postby HurricaneBelle » Fri Sep 14, 2018 4:00 pm

...ISAAC BECOMES A TROPICAL STORM AGAIN BUT ITS FUTURE IS UNCLEAR...


He's just like the rest of us.
7 likes   

jlauderdal
S2K Supporter
S2K Supporter
Posts: 6771
Joined: Wed May 19, 2004 5:46 am
Location: NE Fort Lauderdale
Contact:

Re: ATL: ISAAC - Tropical Storm - Discussion

#728 Postby jlauderdal » Fri Sep 14, 2018 4:07 pm

isaac had a good day, he is cheating death...the models have had a hard time completely killing off the energy so not a huge surprise he still has a shot
1 likes   

User avatar
AnnularCane
S2K Supporter
S2K Supporter
Posts: 2620
Joined: Thu Jun 08, 2006 9:18 am
Location: Wytheville, VA

Re: ATL: ISAAC - Tropical Depression - Discussion

#729 Postby AnnularCane » Fri Sep 14, 2018 4:11 pm

Craters wrote:
SoupBone wrote:
meriland29 wrote:He's the little engine that could(n't). He's trying to desperately cling to life by firing convection, but he's still moving at 16mph. He's not dead (yet), Jim.


Or, converesly, Isaac speaking for himself: "I'm not dead yet! I don't want to go on the cart!"

(https://www.youtube.com/watch?v=UPatfgoNBRo)



Guess he was right. :lol:
1 likes   

User avatar
HurricaneBelle
S2K Supporter
S2K Supporter
Posts: 974
Joined: Sun Aug 27, 2006 6:12 pm
Location: Clearwater, FL

Re: ATL: ISAAC - Tropical Storm - Discussion

#730 Postby HurricaneBelle » Fri Sep 14, 2018 4:12 pm

I love this comment from the discussion, which is basically NHC's way of saying ¯\_(ツ)_/¯

The reality of the situation is that the long-term future of Isaac is cloudy, and the best advice is just to follow NHC advisories every 6 hours to see if we gain any confidence.
11 likes   

User avatar
EquusStorm
Category 5
Category 5
Posts: 1649
Age: 33
Joined: Thu Nov 07, 2013 1:04 pm
Location: Jasper, AL
Contact:

Re: ATL: ISAAC - Tropical Storm - Discussion

#731 Postby EquusStorm » Fri Sep 14, 2018 4:12 pm

Its appearance with persistent convection for over 24 hours and redeveloping banding is very impressive; not surprised it's easily at tropical storm intensity again but just wondered if the LLC was closed. If it stays closed it might well hang on decently well, but it's gonna need to slow down a little to stay closed
0 likes   
Colors of lost purpose on the canvas of irrelevance

Not a meteorologist, in fact more of an idiot than anything. You should probably check with the NHC or a local NWS office for official information.

User avatar
blp
Category 5
Category 5
Posts: 2800
Age: 45
Joined: Thu Sep 09, 2004 7:51 pm
Location: Miami, FL
Contact:

Re: ATL: ISAAC - Tropical Storm - Discussion

#732 Postby blp » Fri Sep 14, 2018 4:13 pm

Very interesting snippet of discussion by the NHC on the intensity. Its going to be interesting how this evolves. I don't feel so bad because looks like they can't figure out either why the models dissipate this.

The intensity forecast hasn't gotten any easier with Isaac.
Vertical shear is expected to decrease a bit more, which might
diminish the effects of dry air seen on water vapor images around
the cyclone. However, the GFS and ECMWF continue to insist that
Isaac will degenerate into a wave within the next 2 or 3 days, which
is almost unanimously supported by their respective ensemble
members.
This is the solution that the official forecast follows.
It should be noted that none of the global models show pressures
this low now with Isaac, except the UKMET, and that model is the one
that holds onto the circulation the longest. The reality of the
situation is that the long-term future of Isaac is cloudy, and the
best advice is just to follow NHC advisories every 6 hours to see
if we gain any confidence.
0 likes   
The following post is NOT an official forecast and should not be used as such. It is just the opinion of the poster and may or may not be backed by sound meteorological data. It is NOT endorsed by any professional institution including storm2k.org For Official Information please refer to the NHC and NWS products.

User avatar
Tampa Bay Hurricane
Category 5
Category 5
Posts: 5594
Age: 36
Joined: Fri Jul 22, 2005 7:54 pm
Location: St. Petersburg, FL

Re: ATL: ISAAC - Tropical Storm - Discussion

#733 Postby Tampa Bay Hurricane » Fri Sep 14, 2018 4:15 pm

Thank you AutoPenalti for posting! Isaac might be trying to wrap up in that image. Going to need to watch it. Euro shows a trough at 120 hours causing Isaac to cross Cuba and get into the Gulf of Mexico. Then it shows a ridge building which would push Isaac NW. The GOM and Caribbean islands need to watch it.
https://photos.app.goo.gl/KR3yvzexEZKaWuCdA
0 likes   

Sciencerocks
Category 5
Category 5
Posts: 7281
Age: 38
Joined: Thu Jul 06, 2017 1:51 am

Re: ATL: ISAAC - Tropical Storm - Discussion

#734 Postby Sciencerocks » Fri Sep 14, 2018 4:16 pm

LOL,

They upgraded to it to a tropical storm and found it closed. It looks the best it has looked since 50 west.

No longer being sheared
Moving into a more favorable environment
Ship, LGEM, and TVCN all show strengthening...The main intensity models on that chart.

I wouldn't stop watching this.
5 likes   

AutoPenalti
Category 5
Category 5
Posts: 3946
Age: 27
Joined: Mon Aug 17, 2015 4:16 pm
Location: Ft. Lauderdale, Florida

Re: ATL: ISAAC - Tropical Storm - Discussion

#735 Postby AutoPenalti » Fri Sep 14, 2018 4:20 pm

Just a hunch, but GFS and Euro may not be taking into account the possible reformation of the LLC to it's South. Maybe by the next run we see some adjustments?
0 likes   
The posts in this forum are NOT official forecasts and should not be used as such. They are just the opinion of the poster and may or may not be backed by sound meteorological data. They are NOT endorsed by any professional institution or STORM2K. For official information, please refer to products from the NHC and NWS.


Model Runs Cheat Sheet:
GFS (5:30 AM/PM, 11:30 AM/PM)
HWRF, GFDL, UKMET, NAVGEM (6:30-8:00 AM/PM, 12:30-2:00 AM/PM)
ECMWF (1:45 AM/PM)

TCVN
is a weighted averaged

User avatar
Hurricane Andrew
S2K Supporter
S2K Supporter
Posts: 1891
Age: 25
Joined: Sun May 23, 2010 2:53 pm
Location: KS

Re: ATL: ISAAC - Tropical Storm - Discussion

#736 Postby Hurricane Andrew » Fri Sep 14, 2018 4:26 pm

18z SHIPS guidance text, for reference...

Code: Select all

TIME (HR)          0     6    12    18    24    36    48    60    72    84    96   108   120
V (KT) NO LAND    35    39    42    45    48    53    57    64    68    73    78    83    90
V (KT) LAND       35    39    42    45    48    53    57    64    68    73    78    83    90
V (KT) LGEM       35    38    40    43    46    52    59    68    77   DIS   DIS   DIS   DIS
Storm Type      TROP  TROP  TROP  TROP  TROP  TROP  TROP  TROP  TROP   N/A   N/A   N/A   N/A

SHEAR (KT)        13     7     7     9    10     4    11     7     9   N/A   N/A   N/A   N/A
SHEAR ADJ (KT)     7     3     2     4     7     4     4     0     3   N/A   N/A   N/A   N/A
SHEAR DIR         25    37    38    41    63    32    19   351   353   N/A   N/A   N/A   N/A
SST (C)         28.7  28.8  28.9  28.8  28.7  28.7  29.1  29.5  29.6   N/A   N/A   N/A   N/A
POT. INT. (KT)   148   149   150   149   147   147   154   161   162   N/A   N/A   N/A   N/A
ADJ. POT. INT.   146   147   146   144   141   141   149   155   157   N/A   N/A   N/A   N/A
200 MB T (C)   -53.4 -53.2 -53.3 -53.4 -53.0 -53.1 -53.0 -53.3 -53.5   N/A   N/A   N/A   N/A
200 MB VXT (C)  -0.2   0.0  -0.1   0.1   0.2   0.2   0.5   0.4   0.2  N/A   N/A   N/A   N/A
TH_E DEV (C)      13    13    12    12    12    11    12    11    11   N/A   N/A   N/A   N/A
700-500 MB RH     48    50    49    52    54    57    56    60    64   N/A   N/A   N/A   N/A
MODEL VTX (KT)    11    10     9     9     8     7     5     5     5  LOST  LOST  LOST  LOST
850 MB ENV VOR    38    40    41    45    46    49    29    28     8   N/A   N/A   N/A   N/A
200 MB DIV        11     0    13    23    11    24     4     5     0   N/A   N/A   N/A   N/A
700-850 TADV       0     1     1     0     0     4     0     0    -1   N/A   N/A   N/A   N/A
LAND (KM)        301   306   281   240   248   258   167   109   229   N/A   N/A   N/A   N/A
LAT (DEG N)     15.3  15.4  15.4  15.5  15.5  15.7  16.3  17.0  17.7   N/A   N/A   N/A   N/A
LONG(DEG W)     67.6  68.9  70.1  71.1  72.2  74.1  76.2  78.3  80.4   N/A   N/A   N/A   N/A
STM SPEED (KT)    13    12    11    10    10    10    11    11    11   N/A   N/A   N/A   N/A
HEAT CONTENT      56    58    64    66    66    89    50    76    64  9999  9999  9999  9999


Ignore the weird "N/A"s, etc, as the LGEM's "DIS" after 72 hours makes no sense to me.

FWIW, both SHIPS and LGEM intensity models bump this to a hurricane. For me, all depends on what that shear does in the western part of the Caribbean.
1 likes   

The Enthusiast
NREMT-AEMT, WX nerd

Irene '11, Sandy '12, Irma '17 (SAR)

"Hard to think we were born to live this way..." -Wage War

RL3AO
Moderator-Pro Met
Moderator-Pro Met
Posts: 16308
Joined: Thu Jun 14, 2007 10:03 pm
Location: NC

Re: ATL: ISAAC - Tropical Storm - Discussion

#737 Postby RL3AO » Fri Sep 14, 2018 4:34 pm

HurricaneBelle wrote:I love this comment from the discussion, which is basically NHC's way of saying ¯\_(ツ)_/¯

The reality of the situation is that the long-term future of Isaac is cloudy, and the best advice is just to follow NHC advisories every 6 hours to see if we gain any confidence.


I was trying to guess who wrote that before looking at the name. I went with Lix, but I can totally see that being Eric Blake. He'll have more zingers in the future I think.
0 likes   

User avatar
Tampa Bay Hurricane
Category 5
Category 5
Posts: 5594
Age: 36
Joined: Fri Jul 22, 2005 7:54 pm
Location: St. Petersburg, FL

Re: ATL: ISAAC - Tropical Storm - Discussion

#738 Postby Tampa Bay Hurricane » Fri Sep 14, 2018 4:49 pm

https://www.tropicaltidbits.com/sat/sat ... roduct=vis
On high resolution imagery it appears that there is some spin and banding near the center but it’s being pushed quickly. It’s speed may be slowing as you get the typical trade wind piling in the western Caribbean.
0 likes   

User avatar
meriland29
Category 2
Category 2
Posts: 770
Joined: Thu Aug 03, 2017 11:05 am

Re: ATL: ISAAC - Tropical Storm - Discussion

#739 Postby meriland29 » Fri Sep 14, 2018 5:11 pm

Of he ends up surviving the dead zone and gets into the Gulf (and that's a big if)...what are the conditions supposed to be like there by the time he would get there in terms of sheer, water temps, etc?
0 likes   

Socalhurcnegirl227
Category 1
Category 1
Posts: 267
Age: 35
Joined: Mon Jun 06, 2016 6:39 pm
Location: Santa Barbara, CA

Re: ATL: ISAAC - Tropical Storm - Discussion

#740 Postby Socalhurcnegirl227 » Fri Sep 14, 2018 5:20 pm

jlauderdal wrote:isaac had a good day, he is cheating death...the models have had a hard time completely killing off the energy so not a huge surprise he still has a shot

hes tryin to live his best life on his caribbean cruise :lol:
5 likes   
"I'm a wandress, i'm a one night stand,
dont belong to no city, dont belong to no man
i'm the violence in the pouring rain,
I'm a hurricane"


Return to “2018”

Who is online

Users browsing this forum: No registered users and 25 guests