ATL: SANDY - Remnants - Discussion

[Tonic]

NHC just posted a statement on Facebook to offer their clarification on the other agencies that will begin issuing warnings once Sandy transforms, but it has already generated a lot of backlash in the comments. I can guarantee the general public will be confused by all of this.

https://www.facebook.com/US.NOAA.Nation ... 1838273302

NHC statement concerning the expected transition of Hurricane Sandy to a Post-tropical cyclone and the flow of information from the National Weather Service:

The National Hurricane Center (NHC) issues advisories, forecasts, and warnings on tropical cyclones - the generic term for hurricanes, tropical storms, and tropical depressions. Sometime prior to making landfall, Hurricane Sandy is expected to lose its characteristics as a tropical cyclone and take on the structure of a wintertime low-pressure area. Because the National Hurricane Center only issues advisories on tropical cyclones, there will be changes in the flow of information coming out of the NWS when this transition occurs.

The primary difference between a tropical cyclone and a wintertime cyclone is the energy source. Tropical cyclones extract heat from the ocean and grow by releasing that heat in the atmosphere near the storm center. Wintertime cyclones (also called extratropical or frontal lows), on the other hand, get most of their energy from temperature contrasts in the atmosphere, and this energy usually gets distributed over larger areas. Because of these differences, tropical cyclones tend to have more compact wind fields, tend to be more symmetric, and have a well-defined inner core of strong winds. Wintertime lows have strong temperature contrasts or fronts attached to them, have a broader wind field, and more complex distributions of rain or snow.

The official NWS term for a tropical cyclone that has evolved into something else is “Post-tropical cyclone”, where the post in post-tropical simply means after. Thus, once Sandy loses its tropical cyclone status it will be known as “Post-tropical Cyclone Sandy” in NWS products. Some aspects of this transition are already occurring, and NWS forecasts of storm impacts are based on this expected evolution. Regardless of when this transition formally occurs, Sandy is expected to bring significant wind, surge, rainfall and inland flooding hazards over an extremely large area, and snowfall to more limited areas.

Because Sandy is expected to make this transition before reaching the coast, the NWS has been using non-tropical wind watches and warnings, issued by local NWS Weather Forecast Offices (WFOs), to communicate the wind threat posed by Sandy in the Mid-Atlantic States and New England. (This is why NHC’s tropical storm warnings extend only into North Carolina.) The NWS plans to continue using non-tropical watches and warnings issued by local offices in the Mid-Atlantic States and northward throughout this event. By using non-tropical warnings in these areas from the start, we avoid or minimize the significant confusion that could occur if the warning suite changed from tropical to non-tropical in the middle of the event.

When NHC determines that Sandy has become post-tropical, NHC advisory products will cease. The NWS will ensure a continuing flow of information through the following:

• NWS WFOs will continue, as they already are, to provide detailed information on local impacts through their regular products. The non-tropical watches and warnings that are in place at the time will remain in effect through the transition.

• The Hydrometeorological Prediction Center (HPC) will take over issuance of Public Advisories on Post-tropical Cyclone Sandy every six hours, under the same product headers as NHC Public Advisories. The HPC Public Advisories will include similar information to the NHC Public Advisory on the current location and strength of the storm, as well as information on the various hazards (wind, surge, and precipitation). The HPC Public Advisories will also contain a track forecast.

• Assuming Sandy becomes post-tropical while its center is still over water, the Ocean Prediction Center (OPC) will discuss the storm in its Marine Weather Discussion. The Marine Weather Discussion will also include the same track forecast contained in the HPC Public Advisory.

• OPC will host a web page for storm support. This page will contain a graphic showing the forecast track of the storm and other information specific to Sandy.

• While NHC's web page will no longer display forecast information about Sandy once responsibility is transferred to other offices, the NHC web page (http://www.hurricanes.gov) will prominently display a collection of links to the other offices’ products, such as HPC’s Public Advisories and precipitation forecast graphics, OPC’s support page and their Marine Weather Discussion, storm surge information from NOAA’s Meteorological Development Laboratory, current water levels data, and regional weather graphics from weather.gov.

• NHC will continue to lead the coordination between NHC, HPC, OPC, and the WFOs throughout the event to ensure consistency of information throughout the NWS.

• NHC will continue to lead the NWS’s coordination with FEMA.

In the event Sandy remains a tropical cyclone through landfall, NHC advisories and products would of course continue. There would be no transition, however, from non-tropical wind warnings issued by the WFOs back to Tropical Storm or Hurricane Warnings issued by NHC, since both sets of warnings describe the same wind hazard.

[GCANE]

18Z GFS showing Sandy coming back to a symmetrical warm core.

http://cimss.ssec.wisc.edu/goes/rt/imag ... 1.2300.gif

Pretty interesting given the fact there is a "cell" trying to strengthen just NW of the LLC and shear is dropping rapidly.

http://tropic.ssec.wisc.edu/real-time/m ... splay.html

http://tropic.ssec.wisc.edu/real-time/w ... oom=&time=

[monicaei]

Well, that's one way to make sure people don't think there's anything to worry about, I guess...

[JtSmarts]

Not issuing those warnings REALLY makes me nervous. I truly hope that the right information is disseminated so people can protect themselves and their property.

[KBBOCA]

Sandy's TS winds now extend 520 miles. Here's a graphical representation. (official NHC graphic)



The original link to the graphic:
http://www.nhc.noaa.gov/storm_graphics/ ... 41R_sm.gif

(edited to change the image link to a saved file, rather than link to the NHC site)

[monicaei]

Isn't it usually the NHC that issues advisories on post tropical systems?

[brunota2003]

Hearing NYC Mayor decided the Battery doesn't need to be evacuated, can anyone confirm that? Aren't they in Zone "A"?

[Hey Its Me]

Isn't it usually the NHC that issues advisories on post tropical systems?

HPC / Local NWS Offices


http://www.hpc.ncep.noaa.gov/

[monicaei]

Isn't it usually the NHC that issues advisories on post tropical systems?

HPC / Local NWS Offices


http://www.hpc.ncep.noaa.gov/

Cool. Did not realize that, thanks. Will they discontinue the NHC track/ plotting/ forecasting this as a tropical system as well?

[Terry]

I'm following things on Twitter and TWC and there are a lot of people pissed at Mayor Bloomberg and the NHC. One has to hope that the NHC will have a chat with him and that he'll do the right thing per evacuations, whatever that is!

[KBBOCA]

The quiet on this site and so many others (even Wunderground is much quieter than usual, though much more active than here) is really beginning to unnerve me. We've not even managed to fill a full 10 pages here in 12 hours today...!!!!

[ROCK]

RECON finding 955-960MB pressure, 2 different planes I believe, 940ish or lower at landfall is not out of the question....

[rosethornil]

I'm in Norfolk, Virginia - within 1/2 mile of the airport and the winds have picked up quite a bit in the last two hours.

Still unseasonably warm and very little rain. Just a bit of drizzle.

[floridasun78]

how are jets going play sunday with type weather their play my team 1pm? it is going safe?

[storm4u]

bloomberg is making the biggest mistake of his life

Hearing NYC Mayor decided the Battery doesn't need to be evacuated, can anyone confirm that? Aren't they in Zone "A"?

[ozonepete]

how are jets going play sunday with type weather their play my team 1pm? it is going safe?

They play in blizzards, lol! but seriously the weather won't be that bad at all tomorrow. It's Monday that will be dangerous.

[ozonepete]

Hearing NYC Mayor decided the Battery doesn't need to be evacuated, can anyone confirm that? Aren't they in Zone "A"?

I haven't heard yet so won't comment. But if the people stay they may be stuck in their high rises for 2 days or more. I hope they stocked up on supplies and those on upper floors stay away from their windows where winds will be much stronger.

[floridasun78]

how are jets going play sunday with type weather their play my team 1pm? it is going safe?

They play in blizzards, lol! but seriously the weather won't be that bad at all tomorrow. It's Monday that will be dangerous.

ok because i want their site their dont talk about weather at all on ny jets.com

[Stephanie]

Wow! All of Staten Island is under water in that image. That is mind boggling. How many homes would be flooded?

Most of Staten Island is well over 10 feet above sea level because it is very hilly island so most of the island won't go under water. It even has a few spots that have the highest land on the northeast coast. But still, they will have severe flooding at their coastline where many homes are only a few feet above sea level. It will be pretty awful if this pans out.

Long Island looks a little thinner in those images. I know that they have a mandatory evacuation along Fire Island. The New Jersey Shore barrier islands which include Long Beach Island and Atlantic City are under mandatory evacuations as well. The casinos are all closing.

[ozonepete]

Sorry I am not getting to all of your questions - I'm getting overwhelmed here as I'm trying to follow Sandy and at the same time getting a lot of questions/texts/emails from family and friends and trying to grade my students' Lab work on tropical meteorology/El Nino. Whew!

But you know I love this stuff, lol.