Thanks Karl. The synoptic setup, along with the TVCN consensus, hinting at a west-coast FLA rake has had me concerned since last night. If the track turns out to be to the left of the guidance envelope, then the NHC intensity estimates are way underdone, given the sea-surface temps in the Gulf.

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.

Land, I know.

Most of these don't push my "hype" button. This one does, because if things line up the wrong way (and so far all the "breaks" are breaking in the BAD direction) the "rake the left coast" forecast will verify with a storm that is highly probable to be in the Cat 3 (and possibly worse) range.

Quote:

Land...are you a meteorologist?

Ulster, no. But have been deeply fascinated with meteorology since I was about 5. Did the storm chasing things and took some photos back in the day, some of which are still archived at the NSSL. Other than that, just a passion.

Nice looking system...

Radar from French Antilles:

000
WTNT44 KNHC 221449
TCDAT4

TROPICAL STORM ISAAC DISCUSSION NUMBER 6
NWS NATIONAL HURRICANE CENTER MIAMI FL AL092012
1100 AM AST WED AUG 22 2012

THE AIR FORCE RESERVE HURRICANE HUNTER AIRCRAFT MONITORING ISAAC
DURING THE NIGHT REPORTED THAT THE INNER CORE WIND FIELD BECAME
DISORGANIZED AFTER 0600 UTC. A COUPLE OF MICROWAVE OVERPASSES
SUGGEST THAT THE CIRCULATION CENTER BECAME ELONGATED DURING THIS
TIME....AND THE CENTER IS NOT READILY APPARENT IN FRENCH RADAR DATA
FROM MARTINIQUE AND GUADELOUPE. THE INITIAL INTENSITY IS HELD AT
40 KT BASED ON AIRCRAFT-REPORTED WINDS NORTH OF THE CENTER. WHILE
THE CENTRAL CORE IS DISORGANIZED...THE OVERALL STRUCTURE OF THE
STORM IS IMPROVING...AS SATELLITE IMAGERY SHOWS A LARGE OUTER BAND
FORMING AROUND THE CENTRAL CONVECTIVE FEATURE.

THE INITIAL MOTION IS A SOMEWHAT UNCERTAIN 280/15...AS IT IS UNCLEAR
HOW MUCH OF THE OBSERVED NORTHWARD NUDGE WAS DUE TO RE-FORMATION OF
THE CENTER. OTHER THAN THAT...THERE IS NO SIGNIFICANT CHANGE TO THE
PREVIOUS FORECAST TRACK OR REASONING DURING THE FIRST 48-72 HR OF
THE TRACK FORECAST. THE EAST-WEST ORIENTED SUBTROPICAL RIDGE TO THE
NORTH OF ISAAC ALONG 30N LATITUDE IS FORECAST BY ALL OF THE GLOBAL
MODELS TO REMAIN INTACT ACROSS FLORIDA AND THE SOUTHEASTERN U.S.
DURING THAT TIME. THIS EARLY PART OF THE FORECAST TRACK IS AN
UPDATE OF THE PREVIOUS FORECAST. AFTER THAT TIME...THE RIDGE IS
EXPECTED TO WEAKEN SOMEWHAT AS A MID/UPPER-LEVEL TROUGH MOVES ONTO
THE EASTERN UNITED STATES. THE MODELS DIVERGE ON THEIR FORECASTS
OF THE RIDGE. THE ECMWF DOES NOT BREAK THE RIDGE...AND THUS
FORECASTS A MORE WESTWARD MOTION NEAR OR SOUTH OF CUBA. THE
CANADIAN AND NOGAPS HAVE A LARGE BREAK IN THE RIDGE AND TURN ISAAC
NORTHWARD EAST OF FLORIDA. THE UKMET HAS A BREAK IN THE RIDGE OVER
THE NORTHERN GULF COAST AND MOVES THE CYCLONE OVER THE FLORIDA
PENINSULA. THE GFS SHOWS A BREAK IN THE RIDGE EAST OF FLORIDA...
BUT FORECASTS ISAAC TO BYPASS THE BREAK AND MOVE NEAR THE SOUTHWEST
COAST OF FLORIDA. THIS DECREASED-CONFIDENCE PORTION OF THE
FORECAST TRACK IS SHIFTED A LITTLE WEST OF THE PREVIOUS TRACK TO
LIE NEAR THE CONSENSUS MODELS.

WATER VAPOR IMAGERY AND MICROWAVE TOTAL PRECIPITABLE WATER DATA SHOW
DRY AIR TO THE NORTHEAST OF ISAAC...AND A LACK OF CONVECTION IN
THIS AREA SUGGESTS SOME OF THIS AIR IS ENTRAINING INTO THE CYCLONE.
OTHERWISE...ENVIRONMENTAL CONDITIONS APPEAR FAVORABLE FOR
INTENSIFICATION UNTIL THE CENTER REACHES HISPANIOLA IN ABOUT 48 HR.
AFTER THAT...THE INTENSITY WILL BE DETERMINED BY HOW MUCH TIME ISAAC
SPENDS OVER LAND. THE NEW FORECAST IS SIMILAR TO THE PREVIOUS
FORECAST THROUGH 48 HR...THEN IS REDUCED A LITTLE BASED ON
INCREASED LAND INTERACTION IN THE NEW FORECAST TRACK.

A HURRICANE WARNING WILL LIKELY BE REQUIRED FOR PORTIONS OF THE
DOMINICAN REPUBLIC THIS AFTERNOON. IT SHOULD BE NOTED THAT WHILE
NONE OF THE FORECAST POINTS ARE OVER LAND...THE CYCLONE IS FORECAST
TO MOVE OVER HISPANIOLA AND CUBA FROM 48-96 HR.


FORECAST POSITIONS AND MAX WINDS

INIT 22/1500Z 15.9N 59.3W 40 KT 45 MPH
12H 23/0000Z 16.3N 61.8W 45 KT 50 MPH
24H 23/1200Z 16.8N 64.8W 50 KT 60 MPH
36H 24/0000Z 17.3N 67.8W 60 KT 70 MPH
48H 24/1200Z 17.8N 70.3W 75 KT 85 MPH
72H 25/1200Z 19.5N 74.5W 60 KT 70 MPH
96H 26/1200Z 22.5N 78.5W 60 KT 70 MPH
120H 27/1200Z 25.5N 81.5W 70 KT 80 MPH

New cone from NHC... as discussed above, official forecast track is shifted to the west.

00Z Euro doesn't buy into the subtropical ridge breakdown, takes it through the Yucatan Channel into the central LA coast in 10 days:

Visible loop

commentary

Outstanding find, Ulster. Bookmarked that site.

Microwave imagery:

I wonder if the Demoncratic convention in September gets one too? Its in Charlotte and Hugo in 1989 hit Charlotte pretty good.

12Z GFS run trends west... Tampa on Tuesday...

Convection looks to be grouped south of the center... probably ingesting some dry air from the north.

Crystal River Nuclear Plant - Elevation above sea level 2 feet

I see a solution that takes the storm right there -- there's a clean argument for the blocking system currently raking the gulf (and which has been for the last couple of weeks -- it's been responsible for the daily deluges we've had until yesterday) lifting out and east.

If it does, and it appears it is going to do so, it leaves the weakness present that has to be there for the system to turn northward and get funneled up along the west coast. Mid-day frames from the GOES complex appear to be confirming that this temporary, last-two-day change in WX here may be an actual pattern change (not to mention that it's very obvious here "on the ground" in this area that the flow HAS changed in the last 36 hours.)

This is looking more likely to hold up -- the only good news is that it probably brings the storm over Hispaniola first which will rip it up pretty good and thus attenuate the intensity. But -- the Gulf is very warm (~31C temps everywhere), and if the system remains "stacked" it can blow up fast -- 24 hours is more than enough for it to regain most of its strength.

Quote:

Crystal River Nuclear Plant - Elevation above sea level 2 feet

They planned that well, didn't they?

It does seem to be struggling with the dry air to the north... if that continues and it remains weak, look for the track to be adjusted farther west. The Euro hasn't done well this season, but it may just be right this time.

Crystal River will be fine. They may have to shut it down due to windage in the intakes and debris that would otherwise wind up in the cooling water intakes, but it's well-protected against being flooded by surge.

Recon just left St. Croix... it'll be interesting to see what they find.

12Z Canadian - Georgia/S. Carolina coast on Monday:

12Z Navy KNOWCRAPS run... south FLA on Monday:

Updated cone from NHC... tones the intensity down a bit.

Latest observations from recon:

Product: Air Force Vortex Message (URNT12 KNHC)
Transmitted: 22nd day of the month at 18:19Z
Aircraft: Air Force Aircraft (Last 3 digits of the tail number are 307)
Storm Number & Year: 09L in 2012
Storm Name: Isaac (flight in the North Atlantic basin)
Mission Number: 3
Observation Number: 02
A. Time of Center Fix: 22nd day of the month at 18:02:20Z
B. Center Fix Coordinates: 16°06'N 60°24'W (16.1N 60.4W)
B. Center Fix Location: 86 miles (139 km) to the NE (50°) from Roseau, Dominica.
C. Minimum Height at Standard Level: 1,479m (4,852ft) at 850mb
D. Estimated (by SFMR or visually) Maximum Surface Wind: 35kts (~ 40.3mph)
E. Location of the Estimated Maximum Surface Wind: 71 nautical miles (82 statute miles) to the NW (314°) of center fix
F. Maximum Flight Level Wind Inbound: From 68° at 35kts (From the ENE at ~ 40.3mph)
G. Location of Maximum Flight Level Wind Inbound: 74 nautical miles (85 statute miles) to the NW (314°) of center fix
H. Minimum Sea Level Pressure: 1004mb (29.65 inHg)
I. Maximum Flight Level Temp & Pressure Altitude Outside Eye: 18°C (64°F) at a pressure alt. of 1,525m (5,003ft)
J. Maximum Flight Level Temp & Pressure Altitude Inside Eye: 21°C (70°F) at a pressure alt. of 1,525m (5,003ft)
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 Levels (sfc and flt lvl centers are within 5nm of each other): Surface and 850mb
O. Navigation Fix Accuracy: 0.02 nautical miles
O. Meteorological Accuracy: 5 nautical miles
Remarks Section:
Maximum Flight Level Wind: 35kts (~ 40.3mph) in the northwest quadrant at 17:39:00Z
Maximum Flight Level Temp: 21°C (70°F) which was observed 8 nautical miles to the NW (314°) from the flight level center

Gut tells me the next cone will show more trending to the west.