ATL HANNA: Extratropical - Discussion

[captain east]

UPPER LEVEL RIDGE OVER THE REGION 12Z THU DIMINISHES AS A SLIGHTLY
AMPLIFYING S/W IN THE NORTHERN STREAM MOVES THROUGH THE NORTHERN
PLAINS. THE APPROACH OF THIS SYSTEM AND THE UPPER LEVEL RIDGE
OFFSHORE WILL PROVIDE THE MAIN STEERING MECHANISM FOR T.C. HANNA.
GFS HAS SHOWN SOME DECENT CONTINUITY WITH THE FORWARD SPEED OF HANNA
IN OUR VICINITY DURING THE PERIOD THU NIGHT THROUGH SATURDAY MORNING
BUT HAS VARIED A BIT AS FAR AS HOW FAR WEST/EAST IT GOES. ECMWF
00Z/31 RUN SLOWER COMPARED TO THE LATEST GFS BUT IT (ECMWF) HAS ALSO
DEMONSTRATED DECENT RUN-TO-RUN CONTINUITY. HPC/TPC COORDINATED
POINTS FOR SATURDAY AND SUNDAY ARE SLOWER THAN MODEL GUIDANCE.
GFS/ECMWF TIMING MAY NOT BE TOO FAR BASE AS POSITION/STRENGTH OF
UPPER RIDGE OFFSHORE AND APPROACH OF S/W IN THE NORTHERN STREAM
SHOULD BE ABLE TO ACCELERATE HANNA TO THE N-NE BY THE WEEKEND. WE`LL
SEE.

[cpdaman]

hanna is moving either SW or W, and thanks to recon going home we don't know yet

also in case anyone wasn't aware ......gustav IMO is showing signs of intensification as he is digesting the warm waters of the loop current .........watch the NE side of LLC toward end of loop

http://hadar.cira.colostate.edu/ramsdis ... ive_0.html

mods can delete this but just thought people should be aware of this trend w/ gustav

[cpdaman]

I'm having a hard time locating the actual center even on the visible loop, but I could swear it just took a dip to the WSW.

IMO the center is tuff to see due to the ULL's easterly band almost over it. and the LLC also appears to be following the ULL SW rapidly

cuba does not appear thaaaat far away at her speed and heading, not calling for this but given the uncertainty in her motion.......

[ericinmia]

[cpdaman]

about 20 hours old but decent winds then , none the less

[ericinmia]

about 20 hours old but decent winds then , none the less

Oh crap, forgot to add the timeframe caption... Thanks! Either way it shows that their is a lot more orginization at the surface than we can easily ascertain through sat images.
-Eric

[cpdaman]

about 20 hours old but decent winds then , none the less

Oh crap, forgot to add the timeframe caption... either way it shows there their is a lot more orginization a the surface than we can easily ascertain through sat images.
-Eric

absolutely that is why the surf has already built to rather impressive levels off the s.e coast already


also bouy ob shows pressure fall still very close to center

http://www.ndbc.noaa.gov/station_page.php?station=41046 (note this will update again in 10 minutes)

29.46

[chadtm80]

[captain east]

I thinks she will become better organized and strengthen overnight...

[cpdaman]

thanks chad, i like how this shows the difference in winds that are of tropical storm nature

anyone that has been in a strong tropical storm will tell you it is "day and nite"

also bouy at (23.85/ 70.85) down to 29.44 and hanna is located SW of it based on wind info

[storms in NC]

Some think she is going to die

Okay now here we go. This is from Wilm
NWC
NATIONAL WEATHER SERVICE WILMINGTON NC
340 PM EDT SUN AUG 31 2008

FRI THROUGH SUN REMAIN THE BIG QUESTION MARKS SO DID NOT MAKE MUCH
IN THE WAY OF CHANGES TO THE FORECAST. WITH HANNA EXPECTED TO BE
OVER OR JUST OFF THE NC COAST LATER THIS WEEK WENT AHEAD AND
INCREASED POPS INTO THE LOW 40S FOR FRI AND SAT. DID NOT GO ANY
HIGHER FOR POPS AS THERE IS STILL A LOT OF UNCERTAINTY IN THE
FORECAST. HANNA MAY NOT SURVIVE THE NEXT 72 HOURS AND EVEN IF IT
DOES...SOME OF THE GUIDANCE KEEPS THE STORM MUCH FARTHER S WHILE
OTHERS PASS THE STORM E OF THE AREA.

NATIONAL WEATHER SERVICE NEWPORT/MOREHEAD CITY NC
329 PM EDT SUN AUG 31 2008
.LONG TERM /THURSDAY THROUGH SUNDAY/...
THE EXTENDED FORECAST WILL BE HIGHLY DEPENDENT ON THE EXACT TRACK
AND INTENSITY OF TROPICAL CYCLONE HANNA. MODEL CONSENSUS AND NHC ARE
SHOWING A NW MOTION OFF THE BAHAMAS AND FLORIDA COASTS WED-FRI W OF
SUBTROPICAL RIDGING. NHC WIND PROBABILITIES BEGIN SHOWING SOME LOW
CHANCES OF TROPICAL STORM FORCE WINDS FOR OUR AREA LATE THU INTO FRI
(LESS THAN 10 PERCENT)...THOUGH IT SHOULD BE NOTED THAT THERE IS
LARGE UNCERTAINTY IN BOTH THE TRACK AND INTENSITY OF HANNA AT THIS
TIME FRAME...AND THUS UNCERTAINTY IN THE LOCAL FORECAST FOR
EASTERN NORTH CAROLINA. AT THIS POINT WE HAVE CONTINUED TO
REINTRODUCE POPS THU NITE WITH A 40 PERCENT CHANCE FOR FRI-SAT
WHEN THE BEST POTENTIAL FOR TROPICAL MOISTURE APPEARS AT THIS
TIME. TEMPERATURES MAY DROP A TOUCH WITH INCREASING CLOUDS/PRECIP
DURING THIS TIME FRAME AS WELL. STAY TUNED.
NATIONAL WEATHER SERVICE RALEIGH NC
250 PM EDT SUN AUG 31 2008
FORECAST THROUGH THIS PERIOD STILL REMAINS HIGHLY UNCERTAIN AND WILL
LIKELY SEE ADJUSTMENTS AS CONFIDENCE IN TIMING INCREASES.

UPPER LEVEL RIDGE OVER THE REGION 12Z THU DIMINISHES AS A SLIGHTLY
AMPLIFYING S/W IN THE NORTHERN STREAM MOVES THROUGH THE NORTHERN
PLAINS. THE APPROACH OF THIS SYSTEM AND THE UPPER LEVEL RIDGE
OFFSHORE WILL PROVIDE THE MAIN STEERING MECHANISM FOR T.C. HANNA.
GFS HAS SHOWN SOME DECENT CONTINUITY WITH THE FORWARD SPEED OF HANNA
IN OUR VICINITY DURING THE PERIOD THU NIGHT THROUGH SATURDAY MORNING
BUT HAS VARIED A BIT AS FAR AS HOW FAR WEST/EAST IT GOES. ECMWF
00Z/31 RUN SLOWER COMPARED TO THE LATEST GFS BUT IT (ECMWF) HAS ALSO
DEMONSTRATED DECENT RUN-TO-RUN CONTINUITY. HPC/TPC COORDINATED
POINTS FOR SATURDAY AND SUNDAY ARE SLOWER THAN MODEL GUIDANCE.
GFS/ECMWF TIMING MAY NOT BE TOO FAR BASE AS POSITION/STRENGTH OF
UPPER RIDGE OFFSHORE AND APPROACH OF S/W IN THE NORTHERN STREAM
SHOULD BE ABLE TO ACCELERATE HANNA TO THE N-NE BY THE WEEKEND. WE`LL
SEE.

AS FAR AS SENSIBLE WEATHER....WILL MAINTAIN WARM/HOT AND DRY
CONDITIONS THU WITH UPPER RIDGE AND ITS SURFACE REFLECTION OVER
OUR REGION. WILL CONTINUE FORECAST OF INCREASING CLOUDINESS THU
NIGHT INTO FRI WITH CHANCE POPS FRI AND SLIGHTLY HIGHER CHANCE POPS
FRI NIGHT THROUGH SATURDAY. DID INCREASE WIND SPEEDS OVER THE EAST
HALF FRIDAY INTO SATURDAY. EXPECT A FAIRLY UNIFORM TEMP FIELD FRI
INTO SAT UNDER MOSTLY CLOUDY/OVERCAST SKIES.

[Evil Jeremy]

AT 500 PM AST...2100Z...THE CENTER OF TROPICAL STORM HANNA WAS
LOCATED NEAR LATITUDE 23.5 NORTH...LONGITUDE 71.4 WEST OR ABOUT 140
MILES...225 KM...NORTH OF GRAND TURK ISLAND.

HANNA IS MOVING TOWARD THE WEST NEAR 10 MPH...17 KM/HR. HANNA IS
EXPECTED TO CONTINUE WESTWARD TONIGHT WITH A DECREASE IN FORWARD
SPEED THEN TURN TOWARD THE SOUTHWEST ON TUESDAY. ON THE FORECAST
TRACK...HANNA WILL GRADUALLY APPROACH THE SOUTHERN AND CENTRAL
BAHAMAS DURING THE NEXT COUPLE OF DAYS.

MAXIMUM SUSTAINED WINDS ARE NEAR 45 MPH...75 KM/HR...WITH HIGHER
GUSTS. LITTLE CHANGE IN STRENGTH IS FORECAST DURING THE NEXT 24
HOURS.

TROPICAL STORM FORCE WINDS EXTEND OUTWARD UP TO 140 MILES...220 KM
FROM THE CENTER.

[gatorcane]

Needless to say that is the best thing to do as Rhome has elected to do but the Florida threat remains still after reading the discussion. One scenario brings it into the East Coast of Florida the other brings Hanna to the Carolinas.

The forecast track lies between these two scenarios and is a "safe bet" at this point until models start to gain convincing consensu.s

SINCE THERE IS NO CLEAR
REASON TO FAVOR ONE SCENARIO OVER THE OTHER AT THIS TIME...I'VE
ELECTED TO LEAVE THE OFFICIAL FORECAST ESSENTIALLY UNCHANGED BEYOND
72 HOURS.

http://www.nhc.noaa.gov/text/refresh/MI ... 2038.shtml

It's important NOT to concentrate on the line in this particular case especially due to model uncertainty

[storms in NC]

Needless to say that is the best thing to do as Rhome has elected to do but the Florida threat remains still after reading the discussion. One scenario brings it into the East Coast of Florida the other brings Hanna to the Carolinas.

The forecast track lies between these two scenarios and is a "safe bet" at this point until models start to gain convincing consensu.s

SINCE THERE IS NO CLEAR
REASON TO FAVOR ONE SCENARIO OVER THE OTHER AT THIS TIME...I'VE
ELECTED TO LEAVE THE OFFICIAL FORECAST ESSENTIALLY UNCHANGED BEYOND
72 HOURS.

http://www.nhc.noaa.gov/text/refresh/MI ... 2038.shtml

Where you been today LOL I one of the discussion from Wilm said {HANNA MAY NOT SURVIVE THE NEXT 72 HOURS } I didn't know that was in play at all. Where is the ULL? Sill south of Hanna or west of her?

[jinftl]

The discussion says "THERE IS NO CLEAR REASON TO FAVOR ONE SCENARIO OVER THE OTHER AT THIS TIME" at 5pm compared to "MOST OF THE TRACK MODELS RESPOND BY TURNING HANNA NORTHWEST WITH AN INCREASE IN FORWARD SPEED" at 11am.....could be reading too much into it...but the UKMET scenario now seems less of an outlier and more of a viable option.

Needless to say that is the best thing to do as Rhome has elected to do but the Florida threat remains still after reading the discussion. One scenario brings it into the East Coast of Florida the other brings Hanna to the Carolinas.

The forecast track lies between these two scenarios and is a "safe bet" at this point until models start to gain convincing consensu.s

SINCE THERE IS NO CLEAR
REASON TO FAVOR ONE SCENARIO OVER THE OTHER AT THIS TIME...I'VE
ELECTED TO LEAVE THE OFFICIAL FORECAST ESSENTIALLY UNCHANGED BEYOND
72 HOURS.

http://www.nhc.noaa.gov/text/refresh/MI ... 2038.shtml

It's important NOT to concentrate on the line in this particular case especially due to model uncertainty

[sfwx]

It doesn't look very healthy. I am wondering if the sheer won't take its toll on Hanna and have her as a weak td or wave in the next few days. I believe the models are having a difficult time with this system because it is so weak.

Eric

[Blown Away]

I always use the Melbourne FL to the south or Wilmington NC to the east for my predictions. I'm sticking with that, I have about is much confidence in a Georgia landfall as I did Hanna going SW over Cuba into the Carribean.

[captain east]

I always use the Melbourne FL to the south or Wilmington NC to the east for my predictions. I'm sticking with that, I have about is much confidence in a Georgia landfall as I did Hanna going SW over Cuba into the Carribean.

Same here, It's been so unpredictable that you pretty much have to place it between those lines...

[cpdaman]

sfwx , not sure that it is "so weak" quikscat shows 35-45 mph winds over a large area (it is no gustav that's for sure)

i don't think anyone should let their guard down as this storm is over some of the warmest waters the atlantic has to offer, should the uLL move further away , and the high push hanna west we could be a couple days a way from a hurricane.

this is not forecast and i'm not saying this will happen, but it is possible and no one should go to sleep on this one

[jaxfladude]

Needless to say that is the best thing to do as Rhome has elected to do but the Florida threat remains still after reading the discussion. One scenario brings it into the East Coast of Florida the other brings Hanna to the Carolinas.

The forecast track lies between these two scenarios and is a "safe bet" at this point until models start to gain convincing consensu.s

SINCE THERE IS NO CLEAR
REASON TO FAVOR ONE SCENARIO OVER THE OTHER AT THIS TIME...I'VE
ELECTED TO LEAVE THE OFFICIAL FORECAST ESSENTIALLY UNCHANGED BEYOND
72 HOURS.

http://www.nhc.noaa.gov/text/refresh/MI ... 2038.shtml

It's important NOT to concentrate on the line in this particular case especially due to model uncertainty

So the First Coast area of NE Fla/SE Ga is still under the possible impact of a land falling Hurricane Hanna(Cat. 1 at this point) if I read the 5pm NHC/TPC discussition right and here on this Hanna thread...