Tropical Depression Isaac:

[TXStormjg]

Interesting... The 11:00am advisory showed Isaac was 26.1 North. The new advisory still shows the same thing. West movement? Looks like it got pulled under the convection.
Not too sure about this NW movement of 14mph.

I am inclined to agree here. Taking the straightedge, the movement seems barely north of west. Meaning, I don't see a 305 degree movement, or NW. Who else sees this?

[Rip76]

Can someone post a quick link to what they're seeing (radar/satellite)...

just a little busy at work.

[srainhoutx]

Product: Air Force Vortex Message (URNT12 KNHC)
Transmitted: 27th day of the month at 18:26Z
Aircraft: Air Force Aircraft (Last 3 digits of the tail number are 306)
Storm Number & Year: 09L in 2012
Storm Name: Isaac (flight in the North Atlantic basin)
Mission Number: 27
Observation Number: 06
A. Time of Center Fix: 27th day of the month at 17:52:10Z
B. Center Fix Coordinates: 26°07'N 85°59'W (26.1167N 85.9833W)
B. Center Fix Location: 252 miles (405 km) to the WSW (239°) from Tampa, FL, USA.
C. Minimum Height at Standard Level: 1,296m (4,252ft) at 850mb
D. Estimated (by SFMR or visually) Maximum Surface Wind: 64kts (~ 73.6mph)
E. Location of the Estimated Maximum Surface Wind: 40 nautical miles (46 statute miles) to the NW (318°) of center fix
F. Maximum Flight Level Wind Inbound: From 57° at 54kts (From the ENE at ~ 62.1mph)
G. Location of Maximum Flight Level Wind Inbound: 37 nautical miles (43 statute miles) to the NW (319°) of center fix
H. Minimum Sea Level Pressure: 985mb (29.09 inHg)
I. Maximum Flight Level Temp & Pressure Altitude Outside Eye: 18°C (64°F) at a pressure alt. of 1,538m (5,046ft)
J. Maximum Flight Level Temp & Pressure Altitude Inside Eye: 22°C (72°F) at a pressure alt. of 1,544m (5,066ft)
K. Dewpoint Temp & 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, Radar, Wind, Pressure and Temperature
N. Fix Level: 850mb
O. Navigation Fix Accuracy: 0.02 nautical miles
O. Meteorological Accuracy: 0.5 nautical miles
Remarks Section:
Maximum Flight Level Wind: 54kts (~ 62.1mph) in the northwest quadrant at 17:39:00Z

[srainhoutx]

Can someone post a quick link to what they're seeing (radar/satellite)...

just a little busy at work.

Too far away for good radar images. Here is the NASA rapid HiRes 1km link.

http://wwwghcc.msfc.nasa.gov/GOES/

[Rip76]

Thank you Srain.

That does have a Wward appearance.
This is what I saw a few hours ago...

[srainhoutx]

Update from Jeff:

No major track shifts have occurred since the 400am advisory. The landfall of tropical storm force winds on the MS River Delta is about 30-36 hours away. The 12Z GFS this morning has trended slightly eastward and a general model consensus is found over SE LA with the GFDL and GFS on the western side of the guidance clustering and the ECMWF, CMC, UKMET on the eastern side (more aimed toward MS).

On the intensity side of things, East Gulf Buoy went very near the center this morning and recorded a pressure of 987mb (now down to 984mb per recon) and sustained winds of around 40-45mph. Dry air has wrapped into the east side of the circulation this morning and weak ENE wind shear is pushing the main convective mass to the WSW side of the circulation. While conditions are generally favorable for development, Isaac still has some issues to overcome and has yet to develop an inner core/eyewall. If the inner core can develop Isaac could make a run at a moderate to strong category 1 hurricane prior to landfall, but the window for intensification is shrinking.

Note: Isaac is a large tropical cyclone with tropical storm force winds extending outward over 200 miles to the east of the center. It is important to not focus on the exact point of landfall and instead the overall range of impacts to the entire area.

Storm Surge:
Do to the large size of the circulation, Isaac will be very capable of moving a large amount of sea water toward the US Gulf coast. Significant storm surge flooding is likely along the MS and SE LA coasts including Lake Pontchartrain. The below listed values are currently forecast on the current forecast track. The exact track of the center is important when dealing with storm surge as the worst of the surge will be near and just east of where the center crosses the coast. Additionally, given the current track, Isaac’s SE wind flow on the eastern side of the circulation will pile water into the concave shape of the coast of SW MS into Lake Pontchartrain. At this time, the current forecasted surge values are below the top limits of the levees protecting SE LA and the City of New Orleans.

Surge Ranges (above sea level):
SE LA (from the mouth of the MS River west to near Houma): 6-9 ft
SE LA (from the mouth of the MS River to the LA/MS state line): 7-11 ft
SE LA (Lake Pontchartrain): 5-8 ft
MS coast: 8-12 ft
AL coast: 6-10 ft
FL panhandle: 3-6 ft

Winds:
Tropical storm force winds are likely from the western FL panhandle to the central Louisiana coast. Hurricane force winds are likely over SE LA and coastal MS. Tropical storm force winds will onset over the lower MS delta around midday Tuesday and spread into metro New Orleans and coastal MS by early evening. Hurricane conditions will spread NW from the mouth of the MS River Tuesday evening into SE LA and coastal MS late Tuesday through Wednesday morning. Due to the large size of tropical storm force winds, adverse conditions will last for hours.

Generally winds will average 60-80mph over the MS delta into New Orleans and the coast of MS with gust to near 90-100mph. Tropical storm force winds will spread well inland over central and eastern Louisiana and much of southern and central Mississippi including Baton Rouge. Main impact from these winds will be downed tree and tree limbs along with power lines and power outages and damage to carports, and siding. Near the coast of SE LA and MS winds may be strong enough to cause minor roof damage. All mobile homes in the hurricane warning area should be evacuated!

Rainfall:
Rainfall amounts are expected to average 8-12 inches near and to the right (east) of where the center crosses the coast or across SE LA and much of MS and AL. Isolated rainfall amounts of 15-20 inches will be possible over extreme E Louisiana into all of MS, AL, and the FL panhandle.

Tornadoes:
As always tornadoes will be possible in the feeder bands of any land falling tropical system. The best tornado potential is usually to the right of the center and can extend well inland and well away from the center. The tornado threat remains highest today across the FL peninsula in the SSE to NNW moving feeder bands and this threat will be shifting toward the MS, AL, and GA area over the next 24-48 hours. Tropical cyclone tornadoes are usually fast moving and brief.

Actions:
The time for action is now in the hurricane warning area…preparations to protect life and property should be rushed to completion and all preparations completed by noon Tuesday. Residents outside of hurricane protection levees and low lying areas and those under evacuation orders should evacuate immediately. Follow all recommendations and advice from local officials.

[srainhoutx]

HPC Diagnostic Discussion for the full evolution of the 12Z Guidance Suite:

TROPICAL STORM ISAAC
====================
PREFERENCE: 12Z ECMWF/12Z GFS COMPROMISE OR 06Z HWRF BY DEFAULT

THE 12Z CANADIAN/12Z UKMET SHIFTED FARTHER EAST THIS
CYCLE...TAKING THE SYSTEM EAST OF JACKSON MISSISSIPPI THURSDAY
MORNING. THE LATEST TRACK FROM THE NATIONAL HURRICANE CENTER
(NHC) SPLITS THE DIFFERENCE BETWEEN THE 12Z ECMWF/12Z NAM AND THE
MORE WESTERN GFS-BASED GUIDANCE (12Z GFS), COMING IN CLOSEST TO
THE 06Z HWRF, WHICH IS PREFERRED BY DEFAULT. THIS SOLUTION LIES
JUST SOUTHWEST OF THE MIDDLE OF THE BROAD 00Z GLOBAL ENSEMBLE
SPREAD (THOUGH IT IS CLOSER THOUGH QUICKER THAN THE 00Z ECMWF
ENSEMBLE MEAN SOLUTION). SEE THE LATEST ADVISORIES AND
DISCUSSIONS FROM THE NHC REGARDING THIS SYSTEM.

[djmike]

I feel the track has finally zoned in and wont be making any further nudges west.... Soooo close, but yet too far. (For great beneficial rains that is...not chaos.)

[Rip76]

yep, that's it I think.

[unome]

3 pm audio update by Franklin http://www.nhc.noaa.gov/audio/201208271908.mp3

[Bluefalcon]

Recon just fixed the center of Isaac...Forward motion at this time has stopped. In appx. 1.5 hours Issac has moved all of 10 miles NNE of its last fix....vortex should be up soon.

[skidog40]

once the flux capacitor injects the fujiwhara effect then it will move.

[djmike]

Ok, the last two posts just lost and confused me.....

[Bluefalcon]

Ok, the last two posts just lost and confused me.....

I'm following Recon mission #27 live with Tropical Atlantic's Google Earth tracking app. Recon's 2nd fix of Isaac's center was 10 miles North and East of the 1st center fix.

[biggerbyte]

I posted this last night:

http://www.ssd.noaa.gov/goes/east/gmex/flash-wv.html

Check off L/L and Trop Pts.

Watch Isaac movement. He has already passed the track laid down by the NHC, and he clearly shows a west to wnw movement.

[djmike]

Ok, the last two posts just lost and confused me.....

I'm following Recon mission #27 live with Tropical Atlantic's Google Earth tracking app. Recon's 2nd fix of Isaac's center was 10 miles North and East of the 1st center fix.

More confused at the "Forward motion at this time has stopped," part.... Sorry if I sound confused, but trying to learn here as I am nowhere close to being any type of pro met. Thanks

[srainhoutx]

Product: Air Force Vortex Message (URNT12 KNHC)
Transmitted: 27th day of the month at 20:07Z
Aircraft: Air Force Aircraft (Last 3 digits of the tail number are 306)
Storm Number & Year: 09L in 2012
Storm Name: Isaac (flight in the North Atlantic basin)
Mission Number: 27
Observation Number: 10
A. Time of Center Fix: 27th day of the month at 19:30:40Z
B. Center Fix Coordinates: 26°14'N 85°56'W (26.2333N 85.9333W)
B. Center Fix Location: 245 miles (394 km) to the WSW (241°) from Tampa, FL, USA.
C. Minimum Height at Standard Level: 1,280m (4,199ft) at 850mb
D. Estimated (by SFMR or visually) Maximum Surface Wind: 43kts (~ 49.5mph)
E. Location of the Estimated Maximum Surface Wind: 11 nautical miles (13 statute miles) to the NNE (12°) of center fix
F. Maximum Flight Level Wind Inbound: From 100° at 54kts (From the E at ~ 62.1mph)
G. Location of Maximum Flight Level Wind Inbound: 19 nautical miles (22 statute miles) to the NNE (19°) of center fix
H. Minimum Sea Level Pressure: 982mb (29.00 inHg)
I. Maximum Flight Level Temp & Pressure Altitude Outside Eye: 20°C (68°F) at a pressure alt. of 1,543m (5,062ft)
J. Maximum Flight Level Temp & Pressure Altitude Inside Eye: 22°C (72°F) at a pressure alt. of 1,544m (5,066ft)
K. Dewpoint Temp & Sea Surface Temp (collected at same location as temp inside eye): Not Available
L. Eye Character: Open in the north
M. Eye Shape & Diameter: Circular with a diameter of 20 nautical miles (23 statute miles)
N. Fix Determined By: Penetration, Radar, Wind, Pressure and Temperature
N. Fix Level: 850mb
O. Navigation Fix Accuracy: 0.02 nautical miles
O. Meteorological Accuracy: 1 nautical mile
Remarks Section:
Maximum Wind Outbound: 65kts (~ 74.8mph) in the southwest quadrant at 19:50:10Z
Maximum Flight Level Wind: 65kts (~ 74.8mph) in the southwest quadrant at 19:50:10Z

[djmike]

I posted this last night:

http://www.ssd.noaa.gov/goes/east/gmex/flash-wv.html

Check off L/L and Trop Pts.

Watch Isaac movement. He has already passed the track laid down by the NHC, and he clearly shows a west to wnw movement.

Wow....is that the first clouds from Issac im seeing arrive in Texas on the Sat loop? I guess thats about as good as we're gonna get...

[srainhoutx]

Product: Air Force Vortex Message (URNT12 KNHC)
Transmitted: 27th day of the month at 20:23Z
Corrected: This observation corrected a previous observation.
Aircraft: Air Force Aircraft (Last 3 digits of the tail number are 306)
Storm Number & Year: 09L in 2012
Storm Name: Isaac (flight in the North Atlantic basin)
Mission Number: 27
Observation Number: 10
A. Time of Center Fix: 27th day of the month at 19:30:40Z
B. Center Fix Coordinates: 26°14'N 85°56'W (26.2333N 85.9333W)
B. Center Fix Location: 245 miles (394 km) to the WSW (241°) from Tampa, FL, USA.
C. Minimum Height at Standard Level: 1,280m (4,199ft) at 850mb
D. Estimated (by SFMR or visually) Maximum Surface Wind: 43kts (~ 49.5mph)
E. Location of the Estimated Maximum Surface Wind: 11 nautical miles (13 statute miles) to the NNE (12°) of center fix
F. Maximum Flight Level Wind Inbound: From 100° at 54kts (From the E at ~ 62.1mph)
G. Location of Maximum Flight Level Wind Inbound: 19 nautical miles (22 statute miles) to the NNE (19°) of center fix
H. Minimum Sea Level Pressure: 982mb (29.00 inHg)
I. Maximum Flight Level Temp & Pressure Altitude Outside Eye: 20°C (68°F) at a pressure alt. of 1,543m (5,062ft)
J. Maximum Flight Level Temp & Pressure Altitude Inside Eye: 22°C (72°F) at a pressure alt. of 1,544m (5,066ft)
K. Dewpoint Temp & Sea Surface Temp (collected at same location as temp inside eye): Not Available
L. Eye Character: Open in the north
M. Eye Shape & Diameter: Circular with a diameter of 20 nautical miles (23 statute miles)
N. Fix Determined By: Penetration, Radar, Wind, Pressure and Temperature
N. Fix Level: 850mb
O. Navigation Fix Accuracy: 0.02 nautical miles
O. Meteorological Accuracy: 1 nautical mile
Remarks Section:
Maximum Wind Outbound: 74kts (~ 85.2mph) in the southwest quadrant at 19:52:30Z
Maximum Flight Level Wind: 74kts (~ 85.2mph) in the southwest quadrant at 19:52:30Z

[biggerbyte]

Wow! I never even noticed that. I was trying to find a center, if you will, to focus on, and get a general idea of movement. I need to drive the point in that, whatever he is doing right now, he is past the point where the NHC says he should be heading NW into LA. We will just have to wait a bit to see what happens with the official track next.