Historic Sandy Oct 26th - 31st, SE hybrid obs/disco thread....

[WeatherNC]

About time we branch this off and give it a separate thread. Local news channels are starting to report on it and traffic will really pick up here in a couple days when we have a Cane off the SE Coast flirting with a potential phase and left hook into the MA/NE. Start with the Big 3 ens means from 12z today H5 anomalies rolled forward 96hrs...

[WeatherNC]

EXTENDED FORECAST DISCUSSION

NWS HYDROMETEOROLOGICAL PREDICTION CENTER COLLEGE PARK MD

329 PM EDT TUE OCT 23 2012

VALID 12Z FRI OCT 26 2012 - 12Z TUE OCT 30 2012

...POTENTIAL FOR MAJOR STORM OVER THE MID ATLANTIC & NORTHEAST

EARLY NEXT WEEK...

PRELIMINARY UPDATE...

UPDATED THE PRELIMINARY FRONTS AND PRESSURES FOR DAYS 3 THROUGH 7

USING THE 00Z/23 EUROPEAN CENTRE ENSEMBLE MEAN, WITH A SMALL

INCORPORATION OF THE 00Z/23 EUROPEAN CENTRE DETERMINISTIC MODEL TO

LEND MORE DEFINITION TO THE SYNOPTIC GRADIENTS ACROSS THE NATION.

USED THE MOST RECENT FORECAST FROM THE NATIONAL HURRICANE CENTER

FOR THE TRACK OF TROPICAL STORM SANDY THROUGH DAY 5, WITH A CURVE

TO THE NORTHWEST DAYS 6 AND 7 BASED ON THE ECENS MEAN. THE 00Z/23

GEM GLOBAL CONTINUES TO CLUSTER WITH THE ECMWF FOR THE BEHAVIOR OF

SANDY ONCE IT TRANSITIONS TO AN EXTRATROPICAL SYSTEM, INDICATING

THAT THE CYCLONE GETS PULLED BACK TOWARD THE SHARP UPPER TROUGH

CLOSING OVER THE OHIO VALLEY. THE ECMWF AND GEM GLOBAL HAVE

SEVERAL RUNS OF CONTINUITY NOW WITH THE EVOLUTION OF THIS EVENT,

WITH THE DETERMINISTIC GFS LESS STABLE. THERE HAVE BEEN GFS

ENSEMBLE MEMBERS QUITE SIMILAR TO THE ECMWF/GEM CAMP FOR THE LAST

FEW DAYS OF MODEL CYCLES, PUTTING THE DETERMINISTIC GFS SOLUTIONS

IN A BROADER FRAMEWORK WITH THEIR TRACK OF SANDY WELL OVER THE

OPEN ATLANTIC. WILL BE UPDATING THE TRACK OF SANDY THROUGH DAY 5

FOR THE FINAL PACKAGE WITH THE ADVENT OF THE NEW NATIONAL

HURRICANE CENTER FORECAST, AND ITS BEHAVIOR AS AN EXTRATROPICAL

LOW THEREAFTER AS PER OUR HOTLINE COORDINATION.

FINAL...

ELECTED TO STAY THE COURSE BY KEEPING THE MAJOR EAST COAST STORM

IN PLAY FOR THE FINAL FORECAST. THE 12Z/23 DETERMINISTIC GFS SENDS

SANDY'S CIRCULATION OUT PAST BERMUDA BY THE END OF THE PERIOD,

WHILE THE 12Z/23 GEFS MEAN INCORPORATES IT ALONG THE EAST COAST IN

LINE WITH THE HPC MANUAL FORECAST. THE 12Z/23 GEM GLOBAL KEEPS

SANDY OUT OF REACH OF THE DIGGING TROUGH OVER NORTH AMERICA,

THOUGH LIKE THE LATEST GFS, IT IS PERHAPS BEST TO REGARD SUCH A

DETERMINISTIC SOLUTION AS A SLIGHTLY SOUPED-UP ENSEMBLE MEMBER.

THE 12Z/23 ECMWF STILL INCORPORATES AN EXTREMELY DEEP

POST-TROPICAL SANDY INTO THE MID-LEVEL PIVOT POINT OF THE POLAR

JET IN THE VICINITY OF LONG ISLAND EARLY NEXT TUESDAY, THE DYNAMIC

TRANSFER RESULTING IN A MINIMUM PRESSURE OF AT LEAST 932MB.

THEREIN LIES THE STORM'S MENACE- A POWERHOUSE CAPABLE OF WHIPPING

THE ATLANTIC INTO A FRENZY AND CHURNING UP DANGEROUS TIDES. OF

PARTICULAR NOTE IS THE COINCIDENCE OF THE FULL MOON ON SUNDAY,

OFTEN A SIGNIFICANT FACTOR IN HISTORICAL EVENTS. THE OCEAN EFFECTS

OF THE SYSTEM MAY STILL BE REALIZED EVEN IF POST-TROPICAL SANDY

DOES NOT MAKE LANDFALL IN THE UNITED STATES. BESIDES THE WIND, THE

OTHER SENSIBLE WEATHER THREAT IS HEAVY RAINS, WITH HEAVY SNOWS

POSSIBLE ON THE SOUTHWEST SIDE OF THE HYBRID CIRCULATION WHERE

CONTINENTAL POLAR AIR RUSHES ACROSS THE CENTRAL APPALACHIANS.

HAVE PREFERRED THE EUROPEAN CENTRE GUIDANCE FOR HANDLING OF THE

MAIN BAND OF WESTERLIES FOR SEVERAL DAYS NOW, ITS SYNOPTIC NUANCES

BEST SERVING THE CENTRAL AND WESTERN UNITED STATES WHERE THE FLOW

OPENS UP IN THE WAKE OF THE AMPLIFICATION OF THE EASTERN TROUGH.

CISCO

[Jon]

http://www.erh.noaa.gov/er/phi/briefing/packages/current_briefing.pdf

NWS Philly not taking any chances, briefing already.

[Jon]

Taken from the NE thread:

12z GFS Ens

12z Euro Ens

Wow....also, GFS no longer OTS technically, 18z shows Nova Scotia hit:

[LithiaWx]

In all seriousness... do those models show a "blizzicane" for parts of the west side of this thing?

[Jon]

In all seriousness... do those models show a "blizzicane" for parts of the west side of this thing?

Absolutely. If this thing hits the way the euro will be showing, there will be several inches (feet) of snow on the western side, depending on how much cold air is involved will also determine how far south the snow goes (possibly into SW VA)....on the eastern side major flooding in coastal areas (obviously) NYC, Long Island, Jersey, etc.

This thing is also very slow moving, haven't looked at it recently but last night it was basically stationary for hours...just hanging out...if it doesn't move quick once it hits we're looking at major flooding for areas that normally don't see it.

and I'll end my post with something suiting my disco

[WeatherNC]

In all seriousness... do those models show a "blizzicane" for parts of the west side of this thing?

I have seen maps with RN in the Catskills and Harrisburg getting clobbered... Several SN maps floating around where central PA measures it in ft.

[WeatherNC]

12z GFS mems from Allan's site @ 168 and 180hrs respectively...

linky: http://raleighwx.americanwx.com/models/gfsensemble/members/12zf180.html

[Cold Rain]

Is there any possible scenario where we get any sort of significant effects down here? If the thing is slower coming out of the Caribbean? If the ridge is taller out west and the trough is sharper...pulls the system west sooner? Anything? Or should we give up and just root for calamity up north?

[buckeyefan1]

Is there any possible scenario where we get any sort of significant effects down here? If the thing is slower coming out of the Caribbean? If the ridge is taller out west and the trough is sharper...pulls the system west sooner? Anything? Or should we give up and just root for calamity up north?

This is what I have done

[pcbjr]

root for calamity up north

Always

[WeatherNC]

Is there any possible scenario where we get any sort of significant effects down here? If the thing is slower coming out of the Caribbean? If the ridge is taller out west and the trough is sharper...pulls the system west sooner? Anything? Or should we give up and just root for calamity up north?

My mind is still wrapped around PA for some reason. Granted, this was a solution the EC and the other two to some extent showed for a couple runs this weekend, and looking through the current perturbations and canceling out noise, I can still see it. Hypothesis: NYC-BOS ground zero then a track WSW into PA as it occludes into the front. For most of us in the SE we may be watching from afar, but indirect impacts could be historic, cancelled flights, telecommunication service interruptions, etc... Coastal areas should get some good wind and erosion, even some hints of a pre frontal RN event here in eastern NC. It would not take a large shift to put NC into some more direct impacts but that remains too far out to be seen currently.

So why the hype? For one you have the ens means (that says a great deal) showing a sig cyclone near the east coast at 7 days. The potential is almost off the charts if Sandy can indeed hook up and phase with the modified polar front pushing through the OH Valley/GL region. Means at this range at valuable as they help to see through smaller scale changes in initial conditions as time is stepped and for the big 3 globals to show 980'ish just off the NE coast at 7 days, yeah, kinda sick nasty.

Next, lets look at the larger scale synoptic features in play. What should be a fairly potent cyclone of tropical origins potentially interacting with digging trough over the northeast United States. Positive height departures in the northern latitudes is somewhat epic, ridge over Bering Straight inducing positive height anomalies into AK coupled with ridging off the southern tip of Greenland extending out into the N Atlantic. NAO is solidly negative and the modeled sharp rise in the PNA over the next 5-7, to slightly above, usually indicates enhanced storm potential along the EC. I use the word usually kind of loosely since there are always caveats, and this is not a usual type scenario even though the broader signals are favorable. MJO is currently in phase 2, however, it looks to be a wave with some amplitude, potentially hitting phase 3 during the event, and per RalieghWX's site phase 3 on Oct show neg departures ivo the NE US.

Red taggers and a boat load of members know way more about this stuff than I do, but for the large scale physics aligning as they appear to be, and the ens means singing alarm bells 7 days out, one has to think the chances of a significant, potentially historic event, are greatly increased.

Direct impacts down south, remote chance NC could see them if this does in fact occlude over PA. Look at some of the goofy solutions shown by the GFS ens above, I count several where NC is wrapped into the cold side with blustery winds and scattered squalls. Pretty crazy stuff, 950 something the central mid-atlantic. That is not as strong as the EC btw...

[WilkesboroDude]

^ Yea some of the models were showing up to one inch of snow for the NC mountains...looks like its going to be colder for many after this mild week...and maybe windy according to NWS Blacksburg. Possibly wind advisory criteria in the mountains.

1923 unnamed hurricane...

[WilkesboroDude]

Wow...was not expecting that this fast. I have doubts that Sandy is a 50mph storm now.

[WilkesboroDude]

Coastal Broward County, Coastal Miami Dade County, Coastal Palm Beach County, FL

Statement as of 6:18 PM EDT on October 23, 2012

... A tropical storm watch might be necessary for portions of the

area later tonight or early Wednesday...

... Winds...

tropical cyclone watches or warnings are currently

not in effect. The latest forecast is for maximum winds to remain

close to but below tropical storm force. At this time... remain

calm and stay informed. Given the uncertainty in the forecast... a

tropical storm watch may still be needed later tonight or

Wednesday morning for portions of the area.

Statement as of 5:00 PM EDT on October 22, 2012

... High rip current risk in effect through Friday afternoon...

The National Weather Service in Miami has issued a high rip

current risk... which is in effect through Friday afternoon.

* Timing... now through Friday

[WeatherNC]

wiki graphic snagged from the main-side thread, last vis image below it...

Quiz: Given the above images which stage?

[WilkesboroDude]

Developing T4 and T5 soon given RI may be soon taking place?

[Cold Rain]

My mind is still wrapped around PA for some reason. Granted, this was a solution the EC and the other two to some extent showed for a couple runs this weekend, and looking through the current perturbations and canceling out noise, I can still see it. Hypothesis: NYC-BOS ground zero then a track WSW into PA as it occludes into the front. For most of us in the SE we may be watching from afar, but indirect impacts could be historic, cancelled flights, telecommunication service interruptions, etc... Coastal areas should get some good wind and erosion, even some hints of a pre frontal RN event here in eastern NC. It would not take a large shift to put NC into some more direct impacts but that remains too far out to be seen currently.

So why the hype? For one you have the ens means (that says a great deal) showing a sig cyclone near the east coast at 7 days. The potential is almost off the charts if Sandy can indeed hook up and phase with the modified polar front pushing through the OH Valley/GL region. Means at this range at valuable as they help to see through smaller scale changes in initial conditions as time is stepped and for the big 3 globals to show 980'ish just off the NE coast at 7 days, yeah, kinda sick nasty.

Next, lets look at the larger scale synoptic features in play. What should be a fairly potent cyclone of tropical origins potentially interacting with digging trough over the northeast United States. Positive height departures in the northern latitudes is somewhat epic, ridge over Bering Straight inducing positive height anomalies into AK coupled with ridging off the southern tip of Greenland extending out into the N Atlantic. NAO is solidly negative and the modeled sharp rise in the PNA over the next 5-7, to slightly above, usually indicates enhanced storm potential along the EC. I use the word usually kind of loosely since there are always caveats, and this is not a usual type scenario even though the broader signals are favorable. MJO is currently in phase 2, however, it looks to be a wave with some amplitude, potentially hitting phase 3 during the event, and per RalieghWX's site phase 3 on Oct show neg departures ivo the NE US.

Red taggers and a boat load of members know way more about this stuff than I do, but for the large scale physics aligning as they appear to be, and the ens means singing alarm bells 7 days out, one has to think the chances of a significant, potentially historic event, are greatly increased.

Direct impacts down south, remote chance NC could see them if this does in fact occlude over PA. Look at some of the goofy solutions shown by the GFS ens above, I count several where NC is wrapped into the cold side with blustery winds and scattered squalls. Pretty crazy stuff, 950 something the central mid-atlantic. That is not as strong as the EC btw...

The potential is definitely there for something historic. That in and of itself is always fascinating. It would be cool to experience part of it. But, even watching from afar is interesting. It will be fun to see how it all plays out. Hopefully, we can get some gusty winds out of it, at least.

And yes, rooting for calamity up north is always a good practice.

[NCSNOW]

I'd say already T4 heading into T5 as we speak

[CandymanColumbusGA]

For areas this far south, I'm more concerned about how chilly we could get IF Sandy phases. The wind, depending on orientation, will be out of the north for a few days, so some may need to crank up the heat for the first time this season (at least if you live south of I-20 ). If we see those northerly winds that strong, some places will struggle to get out of the 50s in Alabama and Georgia and even colder than that in the Appalachians. Again, that's IF Sandy phases. I wouldn't be surprised to see wind advisories go up for much of the East Coast as early as this weekend, especially if Sandy is a bit more west than modeled. That's all if Sandy moves into, say, Long Island. If it makes it up to Boston or farther north, we won't be AS chilly. Yes, the cold front will send temperatures below average next week. The question I've been asking is how much below. In all honesty, I've been telling my viewers that I could be a bit too warm next week with my forecast highs... We'll see. haha!

Also, if that vort max rotating through the Ohio Valley were a bit more south, the 18Z GFS would have phases a bit earlier and slung Sandy northwest earlier. As many have said, this will come down to timing. All the pieces are in place, but are they going to fit together in time to give us a storm every can enjoy, even from afar. That, my friends, is a question we won't fully know until this weekend.

[WeatherNC]

Developing T4 and T5 soon given RI may be soon taking place?

I'd say already T4 heading into T5 as we speak

Based on that last vis pass and the IR/micro graphic Wilkes posted I would say low 4 for the Dvorak t-number, likely solid 4 currently, 4.4-4.6 range. What I was actually looking for, and I apologize for the ambiguous question, was the developmental pattern (v, w, x, y or z). But yeah, you guys nailed the raw T scores...

http://rammb.cira.co...tifier=AL182012

[CandymanColumbusGA]

FWIW, WSI's RPM has Sandy off the coast of Florida as a fairly potent, and large, hurricane. It's in line, maybe a smidge west of the official track from the NHC. Things could get interesting for the east coast of Florida. Heck, as I've said a few times, I'm more interested in seeing if Sandy can give Miami enough rain for them to break their all-time rainfall record! They're about 5" away!

[WeatherNC]

18z Global Ensemble Forecast System (graphic credit SuperStorm93 in the NE sub) All but a few showing the capture, with a heavy cluster into the central MA - southern NE

Pretty crazy on the t-steps though, I see 144's mixed in with 216's

[WilkesboroDude]

Based on that last vis pass and the IR/micro graphic Wilkes posted I would say low 4 for the Dvorak t-number, likely solid 4 currently, 4.4-4.6 range. What I was actually looking for, and I apologize for the ambiguous question, was the developmental pattern (v, w, x, y or z). But yeah, you guys nailed the raw T scores...

hmmm...that looks tricky. Well I think we can knock out z,x,w,.....is it ''v'?

Some of those look monsoonal...exposed...idk I am probably wrong on this.

[WilkesboroDude]

Prob for RI is defiantly there now with a good and developing inner structure. Hurricane Sandy by tomorrow is very probable.

Prob of RI for 25 kt RI threshold= 64% is 5.0 times the sample mean(12.8%)

Prob of RI for 30 kt RI threshold= 55% is 6.6 times the sample mean( 8.4%)

Prob of RI for 35 kt RI threshold= 28% is 5.5 times the sample mean( 5.0%)

Prob of RI for 40 kt RI threshold= 16% is 4.7 times the sample mean( 3.4%)

[WilkesboroDude]

Talk about a close call for Florida...here is the FIM model...which is taking over the GFS eventually. West side could be the strongest in this case.

[WeatherNC]

Credit the NE sub, again... Hopefully this will not be a recurring theme as we head into winter. Site link is directly below, a noaa.gov address.

http://ruc.noaa.gov/tracks/

10/23 UKMET 0z (2nd most accurate model on the planet <120hrs) ENS tracks

10/23 12Z UKMET ENS tracks

10/23 CMC 0z (Canadian is a distant 4th in terms of score at day 5) ENS tracks

10/23 CMC 12z ENS tracks

[WeatherNC]

hmmm...that looks tricky. Well I think we can knock out z,x,w,.....is it ''v'?

Some of those look monsoonal...exposed...idk I am probably wrong on this.

It is "y" fourth row of images down and third graphic in that column , T3 on the intensity, potential to wrap up an inner core quickly, maybe transition towards a "v" down the road but that remains to be seen.

[downeastnc]

So the trend is our friend? Naw just kidding to late in the year to deal with what for us would more likely be a transistioning hurricane.....that said climo would argue that this takes a more smoothed track to the NE not a OTS NE track with a quite sudden left turn, if that were to be the case it would put parts of NC in play I would think

[WilkesboroDude]

Large cloud canopy associated with Sandy...follow the advancing cloud canopy out ahead of it to see where Sandy is heading. Bahamas are ground zero so far.