Tropical Storm Isaac, Part 2: Isaac Moving Into The Gulf Of Mexico-Hurricane Warnings For Morgan City, LA/MS/AL & FL Panhandle To Destin, FL

[phlwx]

The key to that NW movement taking place is when the 850 and surface low finally stack together. If it takes longer to develop, it's (the low center) going to probably miss Haiti as the 850 center keeps tugging west while the LLC struggles to coalesce with the 850.

That said, there will be some impact with Haiti given its larger circulation so even if there isn't a landfall it may be impacted modestly by land before it hits Cuba.

FWIW, Jamaica did issue TS Watches a little while ago.

[phil882]

Latest fix is 15.5N, 70.1W. It looks like the surface circulation has lined up with the 850 hPa circulation based on the dropsonde which has light and variable winds its entire decent. This is probably the actual center location now.

[phlwx]

Latest fix is 15.5N, 70.1W. It looks like the surface circulation has lined up with the 850 hPa circulation based on the dropsonde which has light and variable winds its entire decent. This is probably the actual center location now.

For comparison purposes for those who don't have google earth, etc. 15.5 N, 70.1 W is the tip of the green arrow per google maps.

A due NW component from now brings it east of Aquin...WNW may graze or miss the SW tip of Haiti outright.

[turtlehurricane]

Latest fix is 15.5N, 70.1W. It looks like the surface circulation has lined up with the 850 hPa circulation based on the dropsonde which has light and variable winds its entire decent. This is probably the actual center location now.

Still pandora's box in there, NOAA plane found lowest extrap pressures around 16.0 °N and a weak wind shift at 15.8 °N, at roughly the same time airforce recon confirmed the circulation at 15.5 °N with the sonde. The NOAA plane also found the wind shift at 15.5 °N so we must have multiple features.

[jconsor]

The NOAA plane was flying at 700 mb and even in stronger storms the 700 mb center doesn't always match up exactly with the sfc/850 mb center.

Still pandora's box in there, NOAA plane found lowest extrap pressures around 16.0 °N and a weak wind shift at 15.8 °N, at roughly the same time airforce recon confirmed the circulation at 15.5 °N with the sonde. The NOAA plane also found the wind shift at 15.5 °N so we must have multiple features.

[phil882]

Still pandora's box in there, NOAA plane found lowest extrap pressures around 16.0 °N and a weak wind shift at 15.8 °N, at roughly the same time airforce recon confirmed the circulation at 15.5 °N with the sonde. The NOAA plane also found the wind shift at 15.5 °N so we must have multiple features.

Probably... it appears the 700 hPa is now north of the 850 hPa but no longer by much... so I think we are finally getting this thing vertically stacked.

[phil882]

Current heading based on last three recon VDM fixes is around 310 degrees. On this current trajectory, the center will only skirt southwestern Haiti. Most of the models are forecasting a more poleward motion in the short term. Lets see how this pans out as the circulation becomes vertically stacked.

[Snow_Miser]

Winds up to 45 kts. and pressure is down to 1000 mb in the 8 AM advisory.

[phil882]

The 8 am position the NHC just issued is probably just a touch off. The NOAA-P3 just released a dropsonde in that same area and found deep layer easterlies. The center is probably somewhere between 15.5-15.8 N and a couple of tenths further east based on the latest fixes.

[jconsor]

Pressure is likely around 996 mb based on a NOAA dropsonde at 16.1N reporting 998 mb with 23 kt sfc winds.

The 8 am position the NHC just issued is probably just a touch off. The NOAA-P3 just released a dropsonde in that same area and found deep layer easterlies. The center is probably somewhere between 15.5-15.8 N and a couple of tenths further east based on the latest fixes.

[phil882]

Pressure is likely around 996 mb based on a NOAA dropsonde at 16.1N reporting 998 mb with 23 kt sfc winds.

The position the hurricane hunters found earlier is probably the correct position (15.5N, 70W) given the recent microwave pass. Also, easily the best presentation of Isaac's lifetime. It looks like a more poleward motion is commencing per visible imagery.

[turtlehurricane]

Today is going to be a long day just watching Isaac slowly creep towards Hispaniola, over 275 miles away from landfall and moving at 15 mph, so 18 hours if it didn't slow down. It's probably going to slow down from friction with the island.

[wxsouth]

Last air force center drop had 2 kt at 850 and 4 kt at surface. Definitely getting stacked.

[EasternUSWX]

Recon finding 75+ mph flight winds and 60+ surface. Not suspect either.

[Derecho!]

12Z NHC Model init position:

At 1200 UTC, 24 August 2012, TROPICAL STORM ISAAC (AL09) was located in the North Atlantic basin at 15.9°N and 70.4°W.

[EasternUSWX]

Time: 12:40:00Z Coordinates: 16.1333N 69.4W Acft. Static Air Press: 842.6 mb (~ 24.88 inHg) Acft. Geopotential Hgt: 1,516 meters (~ 4,974 feet) Extrap. Sfc. Press: - D-value: - Flt. Lvl. Wind (30s): From 172° at 60 knots (From the S at ~ 69.0 mph) Air Temp: 13.2°C* (~ 55.8°F*) Dew Pt: -* Peak (10s) Flt. Lvl. Wind: 62 knots (~ 71.3 mph) SFMR Peak (10s) Sfc. Wind: 56 knots (~ 64.4 mph) SFMR Rain Rate: 28 mm/hr (~ 1.10 in/hr) (*) Denotes suspect data

[DaculaWeather]

Time:12:45:00ZCoordinates:16.0167N 69.2333WAcft.

Static Air Press:842.9 mb (~ 24.89 inHg)Acft.

Geopotential Hgt:1,522 meters (~ 4,993 feet)

Extrap. Sfc. Press:-D-value:-

Flt. Lvl. Wind (30s):From 181° at 61 knots (From the S at ~ 70.1 mph)

Air Temp:13.7°C* (~ 56.7°F*)

Dew Pt:-*Peak (10s)

Flt. Lvl. Wind:62 knots (~ 71.3 mph)SFMR Peak (10s)

Sfc. Wind:48 knots (~ 55.2 mph)SFMR Rain Rate:12 mm/hr (~ 0.47 in/hr) (*) Denotes suspect data

[Srain]

Product: Air Force Vortex Message (URNT12 KNHC)

Transmitted: 24th day of the month at 12:58Z

Corrected: This observation corrected a previous observation.

Aircraft: Air Force Aircraft (Last 3 digits of the tail number are 300)

Storm Number & Year: 09L in 2012

Storm Name: Isaac (flight in the North Atlantic basin)

Mission Number: 10

Observation Number: 17

A. Time of Center Fix: 24th day of the month at 12:14:00Z

B. Center Fix Coordinates: 15°40'N 70°26'W (15.6667N 70.4333W)

B. Center Fix Location: 198 miles (318 km) to the S (190°) from Santo Domingo, Dominican Republic.

C. Minimum Height at Standard Level: 1,430m (4,692ft) at 850mb

D. Estimated (by SFMR or visually) Maximum Surface Wind: 31kts (~ 35.7mph)

E. Location of the Estimated Maximum Surface Wind: 69 nautical miles (79 statute miles) to the WSW (258°) of center fix

F. Maximum Flight Level Wind Inbound: From 340° at 26kts (From the NNW at ~ 29.9mph)

G. Location of Maximum Flight Level Wind Inbound: 71 nautical miles (82 statute miles) to the W (261°) of center fix

H. Minimum Sea Level Pressure: 1000mb (29.53 inHg)

I. Maximum Flight Level Temp & Pressure Altitude Outside Eye: 17°C (63°F) at a pressure alt. of 1,525m (5,003ft)

J. Maximum Flight Level Temp & Pressure Altitude Inside Eye: 18°C (64°F) at a pressure alt. of 1,518m (4,980ft)

K. Dewpoint Temp (collected at same location as temp inside eye): 17°C (63°F)

K. Sea Surface Temp (collected at same location as temp inside eye): Not Available

L. Eye Character: Not Available

M. Eye Shape: Not Available

N. Fix Determined By: Penetration, Wind, Pressure and Temperature

N. Fix Level: 850mb

O. Navigation Fix Accuracy: 0.02 nautical miles

O. Meteorological Accuracy: 10 nautical miles

Remarks Section:

Maximum Flight Level Wind: 58kts (~ 66.7mph) in the northeast quadrant at 10:22:00Z

Maximum Flight Level Wind Outbound: 66kts (~ 76.0mph) in the east quadrant at 12:43:40Z

Maximum Flight Level Temp: 18°C (64°F) which was observed 66 nautical miles (76 statute miles) to the WSW (258°) from the flight level center

[am19psu]

Seems reasonable to think that Isaac will be set to 50 kts at the next advisory based on that VDM information.

[DaculaWeather]

It's beginning to have a nice outflow presentation now

http://www.daculaweather.com/4_sat_caribbean.php

http://www.daculaweather.com/4_carb_ft_loop.php

[kab2791]

AL, 09, 2012082412, , BEST, 0, 159N, 704W, 50, 1000, TS, 50, NEQ, 60, 0, 0, 0, 1008, 250, 60, 0, 0, L, 0, , 0, 0, ISAAC, D, 

[DopplerWx]

Storms beginning to pop up around and over the center now.

[audioguy3107]

Beautiful outflow now to the west and southwest. Definitely the best it has looked so far (which isn't really saying a whole lot up to this point).

[Derecho!]

Beautiful outflow now to the west and southwest. Definitely the best it has looked so far (which isn't really saying a whole lot up to this point).

It's always progress when it looks more like a Dvorak chart than a Rorschach Ink Blot.

[NaoPos]

Anyone have a link to the latest MIMIC loop?

http://tropic.ssec.wisc.edu/real-time/storm.php?&basin=atlantic&sname=09L&invest=NO&zoom=4&img=1&vars=11111000000000000000000&loop=0

This might work, but I'm on the iPad. You can see how he "dips" south before he hits the shredder.

Pretty big shift, could it be indicative of 2 or more of the coc's trying to stack up?or is that based solely on the LLC?

[Srain]

Anyone have a link to the latest MIMIC loop?

[SN_Lover]

NHC 11AM update:

60mph winds

1000 mb central pressure

[dan11295]

Track shifted a bit W also.. Any further west and there is potential to go south of Cuba for a while, which would a big deal with regards to near term intensity.

[NortheastPAWx]

He's looking healthy now; and looks like he might only have slight interaction with Hispaniola. Now, does it get stuck with a track of death over Cuba?

[HurricaneFrances04]

Track shifted a bit W also.. Any further west and there is potential to go south of Cuba for a while, which would a big deal with regards to near term intensity.

Shifted west in the short term, east in the long term.