ATL: ISAAC - Post-Tropical - Discussion

[JPmia]

Climatologically speaking.. this site will give you an idea on how rare (rare in terms of time from 1899-2004) for a major to landfall in the Big Bend region.. not saying it won't happen, but it would be a first.

http://www.ncdc.noaa.gov/oa/climate/sev ... ml#earlier

The posts in this forum are NOT official forecast 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.org. For official information, please refer to the NHC and NWS products.

[artist]

A good example as to why not to believe everything you read this is from out local weather site web page
Tropical Storm Isaac is tracking west at about 80 miles per hour, and is about to slam into the lesser Antilles Islands. Isaac is predicted to upgrade to a Hurricane Thursday night as it tracks just south of Puerto Rico. Then Issac’s track looks to shift northwest, over Cuba and into the tip of Florida. Right now he has sustained winds of 40mph.

[SouthDadeFish]

Looks can be deceiving:

[Tireman4]

A good example as to why not to believe everything you read this is from out local weather site web page
Tropical Storm Isaac is tracking west at about 80 miles per hour, and is about to slam into the lesser Antilles Islands. Isaac is predicted to upgrade to a Hurricane Thursday night as it tracks just south of Puerto Rico. Then Issac’s track looks to shift northwest, over Cuba and into the tip of Florida. Right now he has sustained winds of 40mph.

Wow. Just wow. Do they proofread their web page at all?

The posts in this forum are NOT official forecast 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.org. For official information, please refer to the NHC and NWS products.

[Frank2]

Just my own observation, but in the last few photos it seems Isaac is on a 265 or 260 course - we'll see if that's the start of a more westward trend, because this morning's local forecast indicates our South Florida wind to turn from it's present southerly direction to a more eastward component by later in the week, which would indicate that perhaps the trough will have lifted out by then and not be as much of an influence as earlier thought (the Atlantic high behind stronger than forecast), and allowing Isaac to move westward towards Central America...

We'll see...

[Stormlover2012]

This is from lrandy tropical weather underground
In the Atlantic ....



A surface high pressure ridge dominates most of the open tropical Atlantic from 20N to 30N all the way into the Bahamas before we see the influence of the front off the US east coast.

TD#9 is currently near 14N 54W and is moving steadily west at 20 knots. The system has a lot of dry air north of it that is hindering development but the system has been slowly intensifying over the last 48 hours. Wind shear is expected to lessen and water temps will rise so we can expect to see TD#9 become Tropical Storm Isaac soon. In the short term, the models all agree on the westward motion of this system as it develops into a hurricane by about the 36-48 hour point (sometime Thursday). Beyond the 72 hour point, the models vary in their solution. A trough of low pressure in the western US is expected to dig southeast into the SE US by late in the week. The current solution that most of the models agree on is that this trough will dig far enough south to pull this system north. How far north and at what point the turn will occur varies by model with the current spread being anything from the GFS solution up along the west coast of FL to most of the other models that forecast a turn sooner bringing this system up through the Bahamas and up the eastern seaboard.

There are two major considerations in my mind for this forecast. First is the intensity forecast. If TD#9 doesn't become a deep, well defined system, it'll be less affected by the trough. A number of factors can influence the intensity forecast. One is the eastern Caribbean "hurricane graveyard". Low level speed divergence in the eastern Caribbean in the early part of the season is known to quell storm development in this area. However, this system is fairly well developed and we aren't really in the early part of the season anymore so this may or may not have an impact. Also, interaction with land along the Greater Antilles will have a significant impact on intensity.

The second consideration is the tendency of the global models to over-amplify high and low pressure trends in the mid-lattitudes in long range forecasts. It is not at all uncommon for the models to forecast a trough to dig too deep or a high pressure ridge to build too strongly in the long term. So I would take the long range projection for the trough digging too far into the Gulf with a grain of salt, especially this time of year.

So what would all this mean for the long term forecast for this storm? If the models are wrong about the trough digging so far south, or the storm doesn't develop as well and as deep as forecast, then the system won't turn north as forecast or at the rate that is forecast. That would mean a more westerly track. As usual, we'l have to wait and see with each new model run. But it won't surprise me to see future runs nudge the track forecast further and further west.

The other news in the Atlantic is Invest 96L in the far east Atlantic. This system is a bit further south than TD#9 was at the start and it gets to ride along in the moisture trail of TD#9 so I think it's a pretty safe bet that this system will develop. The model forecasts are iffy at the moment since the models are often not too accurate until the systems become well developed so I wouldn't speculate just yet on the long range forecast for this system but for the moment it will stay on a westward track around the southern edge of the high pressure ridge dominating the Atlantic. Warm water, low shear, and a fairly moist environment all point toward development of this system.

I'll post again tomorrow as these systems develop.

Have a great day!

Randy

[hurricanefloyd5]

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE MELBOURNE FL
930 AM EDT WED AUG 22 2012

SUN-TUE...ATTENTION TOWARD ISAAC DURING THE WEEKEND TRANSLATES TO
HIS POSSIBLE EFFECTS ON AREA EARLY NEXT WEEK. NHC FORECAST DAY 5
POSITION CURRENTLY JUST NORTH OF THE CENTRAL CUBA COAST SUNDAY EVE
WITH ANTICIPATED DRAWING NWD OF THE FORECAST TRACK DUE TO
INTERACTION WITH US EAST COAST TROUGH. UNCERTAINTY EXISTS WITH
REGARD TO STRENGTH OF THE MID TROPOSPHERIC RIDGE CURRENTLY NORTH OF
ISAAC AND THE EVENTUAL WEAKENING OF THE WWD EXTENT OF THE RIDGE AND
ONSET OF INTERACTION WITH THE US EAST COAST TROUGH. LATEST 00Z ECMWF
RUN INDICATES A STRONGER MORE EXPANSIVE WWD EXTENSION OF THIS RIDGE
AND THUS A MORE WWD MOTION OF ISAAC TOWARD THE EASTERN GULF. IT IS
HOPED THE HIGH ALTITUDE G4 SURVEILLANCE FROM THE NOAA JET BEGINNING
THURSDAY WILL SAMPLE THE REGION AROUND ISAAC AND PROVIDE ADT`L INFO
FOR MODEL GUIDANCE.

[wxwatcher1999]

Wow seems like more and more people are mentioning the possibility of a westerly track

[adam0983]

Does anyone know how large the windfield with Tropical Storm Isaac will be? Looking great on a radar this morning. This storm comes down to when does the high get weak and when does the ridge break down.

[KBBOCA]

From the Goes Floater Visible, it looks like the western edge of the CDO is about to affect the island of Martinique.

Sorry - lousy internet connection today, so I can't upload graphics easily.

[Frank2]

LATEST 00Z ECMWF
RUN INDICATES A STRONGER MORE EXPANSIVE WWD EXTENSION OF THIS RIDGE
AND THUS A MORE WWD MOTION OF ISAAC TOWARD THE EASTERN GULF

Exactly - that's what our Miami WSFO indicates as well in the local forecast from early this morning - my guess is that the models will soon reflect this with a leftward bend in the cone...

Frank

[uhvjaguars22]

Personal Forecast Disclaimer:
The posts in this forum are NOT official forecast 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.org. For official information, please refer to the NHC and NWS products.


im going to go ahead and call my landfall location of galveston to new orleans i may be way wrong though. and it would be a heck of a call from the gfs last week showing a texas landfall

opinion

[Tyler Penland]

Last hour looks like he's wobbled south. Main convection did anyways.

http://www.ssd.noaa.gov/PS/TROP/floater ... short.html

[Tireman4]

The posts in this forum are NOT official forecast 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.org. For official information, please refer to the NHC and NWS products.

im going to go ahead and call my landfall location of galveston to new orleans i may be way wrong though. and it would be a heck of a call from the gfs last week showing a texas landfall

opinion

Wow. Bold move there. Goodness.

[Extratropical94]

A good example as to why not to believe everything you read this is from out local weather site web page
Tropical Storm Isaac is tracking west at about 80 miles per hour, and is about to slam into the lesser Antilles Islands. Isaac is predicted to upgrade to a Hurricane Thursday night as it tracks just south of Puerto Rico. Then Issac’s track looks to shift northwest, over Cuba and into the tip of Florida. Right now he has sustained winds of 40mph.

Wow. Just wow. Do they proofread their web page at all?

The posts in this forum are NOT official forecast 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.org. For official information, please refer to the NHC and NWS products.

A local website/newspaper here also posted something about Isaac a few hours ago (translated):
Tourists and resident in the Lesser Antilles are on the alert since Monday. Hurricane "Isaak" is expected to move through the area, then impact Puerto Rico and head towards the US. (...) Intensity models are very agressive and bullish on the system and all signs are pointing towards a major hurricane (category 3+). "Isaak" has the potential to enter the history books as wind speeds above 220 km/h (135 mph) and scenarios like the Great Hurricane of 1780 that killed more than 22,000 people can't be ruled out. (...) Going with currend trends, the hurricane is forecast to impact Florida or the US East coast on Saturday night.

I think such posts are irresponsible and full of mistakes that happen when writers don't do enough research, especially when handling such an important topic.
I know this storm won't get too much attention here in Germany unless it hits the US mainland but still I'm really shocked what I have to read sometimes.

[Hurricane Andrew]

The posts in this forum are NOT official forecast 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.org. For official information, please refer to the NHC and NWS products.

0 Hours, 45mph, TS
12 Hours, 45mph, TS
24 Hours, 50mph,TS
48 Hours, 60mph, TS

My forecast. Thoughts?

[Bocadude85]

Last hour looks like he's wobbled south. Main convection did anyways.

http://www.ssd.noaa.gov/PS/TROP/floater ... short.html

Thats from the NE shear.. not a movement.

[Tyler Penland]

Last hour looks like he's wobbled south. Main convection did anyways.

http://www.ssd.noaa.gov/PS/TROP/floater ... short.html

Thats from the NE shear.. not a movement.

Good to know.

[hurricanefloyd5]

dose anyone have radar from this area?

[ROCK]

nice looking TS now this morning....maybe it can maintain today and stay out of the SAL buffet.....