ATL: SANDY - Remnants - Discussion

[tolakram]

It appears to be close to on track. I used a circle tool to draw a curve between the two forecast points.

[gatorcane]

The NNW turn appears it may be commencing as expected. The system was giving hints of that this morning after rolling of Cuba and slowing some. Question is how much west does it goes and how much does the system expand on the west side? Looks like it is expanding on the west side now....

[adam0983]

How strong do you think the winds will be in Palm Beach County?

[tolakram]

Latest, 15:55Z hires from the FTP site



ftp://goes.gsfc.nasa.gov/pub/goeseast/overview2/vis/

[Bocadude85]

How strong do you think the winds will be in Palm Beach County?

Probably 35-40mph with gusts to 45mph. Thats what the NWS Miami is calling for.

[Bizzles]

What's your guess based on?

ozonepete,

The GFS shows Sandy being absorbed by a large cutoff low forecast to drop through the Appalachians and pinwheels it around in the Atlantic before making landfall on the US/Canadian border - to seem like it's just too late in the season for a landfalling US hurricane, especially in NYC, but never say never...

Frank

But the GFS is gradually moving toward the euro (Delmarava coast) and cmc (New York) solutions. By the way, it is NOT forecast to be absorbed - rather it will be energized by upper level divergence just east of the nose of the approaching vigorous 500mb shortwave trough. This upper divergence has energized many a fading hurricane and given it a new life as a hybrid, e.g. Hurricane Hazel in October of 1954 which went fully extratropical while coming ashore at the NC/SC border and then caused hurricane winds all the way to Canada.
The consensus of the models, which the NHC almost always uses, has Sandy transitioning to a hybrid storm between the VA Capes and NYC so it's a post-tropical storm at landfall. But notice they have winds of 70 mph still associated with it as it comes near the Jersey shore. It will not make much difference whether it's tropical or extra-tropical or what it's called to anyone on the Jersey shore trying to deal with a 10 foot storm surge and 70 mph winds.

Well said!

[Aric Dunn]

Riding building in. should see the nnw to nw turn become more apparent very soon.

[Sanibel]

It's not a normal year so the Euro negative tilt is possible.


Look how once Sandy hit land it sent its black IR out to that remote band to the ESE.

[HPC]

Observations: 2.4 miles inland, Jupiter, FL. (local time, wind and today's rainfall data)
09:15__ Current(mph):09.3__ CurrentGust(mph):17.3__ 1HourAvg(mph):09.7__ MaxGustToday(mph):25.6__ RainToday(in):0.02
10:15__ Current(mph):11.1__ CurrentGust(mph):14.0__ 1HourAvg(mph):08.6__ MaxGustToday(mph):25.6__ RainToday(in):0.02
11:15__ Current(mph):09.7__ CurrentGust(mph):10.4__ 1HourAvg(mph):08.3__ MaxGustToday(mph):25.6__ RainToday(in):0.02
12:15__ Current(mph):07.6__ CurrentGust(mph):12.7__ 1HourAvg(mph):08.4__ MaxGustToday(mph):25.6__ RainToday(in):0.02

[Frank2]

P.S. I read your posts, ozonepete - I forgot about Hazel's very unusually large wind field (I think they even had substantial wind damage in Toronto), and thanks for explaining why Sandy might get energized by the trough, rather than absorbed...

Just went out for lunch - overcast, breezy at times, warm and very humid (well, it is South Florida - we don't complain until the DP reaches 80 - no kidding)...

But, if I had to bet the ranch, and the chickens and the possum, too, I'd bet that Sandy will remain offshore - my brother and his family live in coastal New Jersey and my Aunt in coastal Maine, so I'm biased...

[Aric Dunn]

last few radar images of the center. general north motion should turn soon.

[Houstonia]

Jeff Lindner (Meteorologist with Harris County Flood Control District, Houston, TX) :

Strong hurricane Sandy heading for the Bahamas while lashing SE FL

Potential major storm event for the NE/mid Atlantic late this weekend/early next week.

Discussion:

Hurricane Sandy has moved off the northern coast of Cuba this morning and continues to look very well organized on satellite images. Recon aircraft yesterday evening prior to landfall indicated 126kt flight level winds with a 20-24 mile wide diameter eye surrounded by deep intense thunderstorms. Punta Lucrecia, Cuba recorded sustained winds of 96mph with gust to 118mph overnight. While the inner core of the hurricane was likely disrupted some by the passage over the high mountains of SE Cuba, the system remains well organized as it heads for the central Bahamas. In fact the last few satellite images suggest the eye may be clearing out some and the system starting to take advantage of the warm se state over the central Bahamas.

Track:

The track of Sandy will likely become the main story for the next several days as a set of highly unusual parameters come together to potentially bring a powerful tropical or extra-tropical storm system to the NE US coastline. The model track guidance is in good agreement on Sandy moving generally northward for the next 24-36 hours followed by a turn toward the NNE and NE in the 36-72 hour period as a large trough approaches the US east coast. In most instances, a tropical system on the eastern flank of a strong trough would be pushes NE or ENE out to sea however this trough will dig into the SE US and becoming increasingly negatively tilted resulting in an increasingly strong SSE or SE steering flow over the NE Atlantic as Sandy moves just east of the North Carolina coast. This results in all of the track guidance bringing Sandy back toward the NNW or NW and striking the mid Atlantic of NE US as a powerful tropical or extra-tropical storm system (nor’easter). As shown below there is considerable spread in the model guidance with the GFS the furthest east and north with impacts mainly to Atlantic Canada and Maine, while the GFDL , ECMWF, and NOGAPS are much further to the south and show the system moving inland over the DELMARVA or NJ bringing very serious impacts to the NE US coastline. Based on the highly unusual pattern that will be in place the forecast confidence is extremely low at this point….but the potential is there for a very significant weather event over the NE US early next week.

Intensity:

The short term intensity will be control by the ability of the inner core to consolidate and draw energy from the warm ocean below. This process appears to be underway and I suspect Sandy will deepen as she moves across the Bahamas possibly becoming a category 3 hurricane. Most guidance shows Sandy peaking in the next 12-24 hours prior to the onset of strong SW wind shear, but there is much uncertainty on if the wind shear come be negated by the forward motion (although the system will be slowing) and the potential for increasing baroclinic processes.

Further out in time, the forecast becomes highly complicated and really hard to explain. Sandy will move either along or on the eastern edge of the warm Gulf stream and could continue to feed off those warm waters. Aloft the system will begin to feel the effects of the mid latitude jet stream and this energy from the trough to the west will translate into Sandy and help either maintain or intensify the system. Once the hurricane clears the latitude of North Carolina, it is hard to determine if it will be tropical in nature or more similar to a nor’easter with cold and warm fronts attaches (extra-tropical). Some of the latest mode guidance phase diagrams keep the system more warm core with high inner core rainfall rates…suggesting more tropical in nature. One thing is for sure the wind field will greatly expand which begins to transfer energy outward across the diameter of the storm instead of focused near the center as is true in a purely tropical hurricane or in Sandy’s current state.

Of even more interest is the insanely low pressures the models are driving toward the NE US coast. The GFDL brings a monster 938mb low into the DELMARVA while the HWRF model shows pressure way down around 930mb several hundred miles south of Long Island. These are incredibly low pressures, and all forecast models have Sandy as a sub 960mb storm as it potentially impacts the NE US. These extremely low pressures correlate to a category 4 hurricane in the tropics, but as mentioned above it remains to be seen if Sandy is purely tropical when she reaches these higher latitudes. The current thinking is that while the pressures will be extremely low, the large wind field will expend the energy over a wide area and the wind/pressure relationship will be offset compared to normal. Thus I do not expect a category 4 hurricane strike on the NE US, but a large storm with winds of 70-90mph will be possible which will cause “incredible” impacts.

Impacts:

While there remains much uncertainty in the track and intensity and the shape of Sandy as she moves toward the NE US, the potential if there for some very serious impacts. Lunar tides will be highest with the full moon on Monday (10-29) which will only worsen the threat for severe coastal flooding.

While this system has some similarities to the “Perfect Storm or the Halloween Storm of 1991” made famous by the movie where a nor’ easter absorbed Hurricane Grace and then bettered the NE US coast for days, this current event would result in a more direct hit on the coast with an inland moving storm system displaced south and west of the 1991 storm with much bigger coastal impacts.

[Blown Away]

http://www.ssd.noaa.gov/PS/TROP/floater ... short.html

IMO, clearly the NW to NNW turn began an hour ago.

[Aric Dunn]

9 hrs ago no ridge large break


now ridging filling in in all layers. should be slowing down and it has the oblong squashed looked just before they turn.

[tolakram]

Latest, eye clearing out.

[WeatherOrKnot]

IMO, clearly the NW to NNW turn began an hour ago.

I totally agree.

[MiamiensisWx]

How sharp does anyone (preferably a meteorologist) think the turn will be? My guess is that the NNW movement will still allow the center to pass more than five-tenths of a degree east of Nassau, New Providence.

[CrazyC83]

Once the wind field (not just cloud deck) expands, I would expect the central pressure to fall, although the wind speeds may not respond much.

[Aric Dunn]

recon .. 958 with a 32kt wind. they missed the center again it appears.

[CrazyC83]

recon .. 958 with a 32kt wind. they missed the center again it appears.

That would be a 955mb pressure.