Isaac

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Isaac

Post by Caribbean Traveler » Fri Sep 07, 2018 4:40 pm

Friday Evening Update

TD 9 finally classified

The Weather Situation
Tropical depression 9 has finally been classified. It likely had already formed at least 24 hours ago. NHC previously stated that the low pressure was elongated. Today east wind shear exposed the center showing that indeed a low center had formed.

Current Tropical Weather
As of 5:00 PM AST TD 9 was centered at 13.6 N / 34.9 W or 1755 miles east of the Windward Islands. It was stationary. Top sustained winds are estimated at 35 mph. Pressure was estimated at 1007 MB.

Tropical Weather Forecast:
Forecast models show TD 9 strengthening and possibly taking a low latitude track which may threaten the Lesser Antilles several days from now.

Tropicast: Wednesday Afternoon Visible Satellite
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Tropicast: Thursday Afternoon Visible Satellite
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Tropicast: Friday Afternoon Visible Satellite
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Re: Tropical Depression 9

Post by Caribbean Traveler » Sat Sep 08, 2018 10:50 am

Saturday Afternoon Update

TD 9 really is Isaac

The Weather Situation
Tropical depression 9 will be classified as Tropical Storm Isaac later today. Deep convection has moved over the center of circulation once again and IMO is now a storm.

Current Tropical Weather
As of 11:00 AM AST TD 9 was centered at 14.6 N / 36.0 W or 1680 miles east of the Windward Islands. It was moving WNW at 6 mph. Top sustained winds are estimated at 35 mph. Pressure was estimated at 1007 MB.

Tropical Weather Forecast:
Forecast models show TD 9 strengthening and possibly taking a low latitude track which may threaten the Lesser Antilles several days from now.

Tropicast: Visible Satellite
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Re: Isaac

Post by Caribbean Traveler » Sun Sep 09, 2018 3:38 pm

Sunday Evening Update

Isaac slowly strengthing

The Weather Situation
Isaac is still fighting wind shear.


Tropical Weather Forecast:
Forecast models show Isaac move into the eastern Caribbean as a possible minimal hurricane or possible tropical storm.

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Re: Isaac

Post by Caribbean Traveler » Mon Sep 10, 2018 6:03 pm

Monday Evening Update

Isaac fighting shear

The Weather Situation
Isaac is likely no longer a hurricane. It has been battling wind shear and it appears that the low center is displaced from the deepest convection.

Current Tropical Weather
As of 5:00 PM AST Isaac was centered at 14.4 N / 45.3 W or 1090 miles east of the Windward Islands. It was moving west at 14 mph. Top sustained winds are estimated at 75 mph. Pressure was estimated at 993 MB.

Tropical Weather Forecast:
Forecast models show Isaac move into the eastern Caribbean as a possible minimal hurricane or possible tropical storm.

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Re: Isaac

Post by Caribbean Traveler » Tue Sep 11, 2018 8:21 am

Tuesday Morning Update

Isaac finally downgraded

The Weather Situation
For whatever reason, NHC seems slow on this system. TD 9 appeared to be Isaac a full day before being upgraded and now it seems that it wasn't at hurricane strenght yesterday. Buoy data confirmed the small wind field overnight and NHC finally downgraded to a tropical storm early this morning. Dvorak estimations this morning actually look higher than yesterday. With that being said, I agree with NHC's assessment of 70 mph, but believe that it may have actually dropped to 60-65 mph yesterday.

Current Tropical Weather
As of 5:00 AM AST Isaac was centered at 14.6 N / 48.1 W or 880 miles east of the Lesser Antilles. It was moving west at 14 mph. Top sustained winds are estimated at 70 mph. Pressure was estimated at 997 MB.

Tropical Weather Forecast:
Forecast models will take Isaac generally westward toward the Lesser Antilles then into the Caribbean. Right now estimates show either a minimal hurricane or tropical storm as it passes into the Caribbean.


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Re: Isaac

Post by Caribbean Traveler » Wed Sep 12, 2018 7:37 am

Wednesday Morning Update

Isaac struggling

The Weather Situation
Isaac has struggled its whole lifetime. In fact, I don't believe that it was ever a hurricane. Forecast models have shown favorable conditions for development, but they never materialized. IMO, I wondering if the strengthening of Florence well to its NW has increased shear. Today Isaac is still fighting westerly shear with the deep convection to the SE of the circulation center.

A reconnaissance aircraft will arrive soon.

Current Tropical Weather
As of 8:00 AM AST Isaac was centered at 14.4 N / 54.1 W or 450 miles east of Martinique. It was moving west at 15 mph. Top sustained winds are estimated at 70 mph. Pressure was estimated at 1000 MB.

Tropical Weather Forecast:
Forecast models take Isaac generally westward toward the Lesser Antilles then into the Caribbean. Right now estimates show a tropical storm as it passes into the Caribbean.


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Re: Isaac

Post by Caribbean Traveler » Thu Sep 13, 2018 7:42 am

Thursday Morning Update

Isaac very weak

The Weather Situation
Reconnaissance aircraft currently in Isaac show that it is a minimal tropical storm. Satellite imagery also indicate that the circulation center is stripped of deep convection. Some deep convection remains to the east of the center which will bring locally heavy rainfall to parts of the Lesser Antilles

Current Tropical Weather
As of 8:00 AM AST Isaac was centered at 15.2 N / 60.9 W or 25 miles east of Dominica. It was moving west at 21 mph. Top sustained winds are estimated at 45 mph. Pressure was estimated at 1006 MB.

Tropical Weather Forecast:
Forecast models take Isaac into the central Caribbean the next few days. Little change in strength is expected, and it is possible that it could degenerate into a wave.


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Re: Isaac

Post by Caribbean Traveler » Thu Sep 13, 2018 4:06 pm

Thursday Evening Update

Isaac barely holding on

The Weather Situation
Satellite imagery still shows a low level circulation but no winds to tropical storm force were seen in the Lesser Antilles as it passed by today. IMO it is now a depression. There are still heavy rain showers to the east of the circulation.

Current Tropical Weather
As of 5:00 PM AST Isaac was centered at 14.9 N / 63.2 W or 220 miles SSE of St. Croix. It was moving west at 16 mph. Top sustained winds are estimated at 40 mph. Pressure was estimated at 1006 MB.

Tropical Weather Forecast:
Forecast models take Isaac into the central Caribbean as a tropical depression / wave over the next few days.


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Re: Isaac

Post by Caribbean Traveler » Fri Sep 14, 2018 8:52 am

Friday Morning Update

Isaac downgraded

The Weather Situation
Isaac has been downgraded to a tropical depression, but actually looks more organized than the last few days. The official forecast keeps it as a tropical depression, but be wary of any redevelopment.

Current Tropical Weather
As of 5:00 AM AST Isaac was centered at 15.0 N / 65.5 W or 190 miles SSW of St. Croix. It was moving west at 15 mph. Top sustained winds are estimated at 35 mph. Pressure was estimated at 1006 MB.

Tropical Weather Forecast:
Forecast models take Isaac into the central / western Caribbean as a tropical depression / wave over the next few days. It appears that Isaac is reorganizing despite what forecasts are showing. There is a possibility of it regaining tropical storm strength.


Tropicast: Visible Satellite
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NHC Forecast
https://www.nhc.noaa.gov/text/refresh/M ... 831.shtml?

NHC Track
https://www.nhc.noaa.gov/graphics_at4.s ... e#contents
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Re: Isaac

Post by Caribbean Traveler » Fri Sep 14, 2018 3:59 pm

:idea: Isaac was upgraded to tropical storm again at the 5 PM EDT advisory.
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