Ed Lizard Posted October 22, 2012 Share Posted October 22, 2012 This thing won't be interesting for a few days. Lots of flooding likely in the Jamaica and Eastern Cuba, then will intensify over the Bahamas Thursday/Friday. After that, who knows? Could go out to sea, could head to the Maritimes, or could be a Hazel-redux. Personally, I think the Maritimes are the most likely landing spot, but I put out about a 25% chance of Hazel Pt 2 today. Adam., are you a Josh tropical purist, or does the post tropical MegaDeth storm of the Euro (and Canadian is Detroit Rock City) appeal to you? Personal preference, I'll take post tropical fun for New England/NY/Mid Atlantic over a fish escaping East. ETA- Raleigh Euro Ensemble means might support the less fun GFS solution offshore. Link to comment Share on other sites More sharing options...
LakeEffectKing Posted October 22, 2012 Share Posted October 22, 2012 GGEM holds serve....nasty time for the Jersey shore: Link to comment Share on other sites More sharing options...
LakeEffectKing Posted October 22, 2012 Share Posted October 22, 2012 LOL! For Sheets and giggles I pulled up the 12z NoGaps.....and it would hint at the possibility of a snowstorm for W. NY/PA.... Link to comment Share on other sites More sharing options...
wxmx Posted October 22, 2012 Share Posted October 22, 2012 For posterity Link to comment Share on other sites More sharing options...
wxmeddler Posted October 22, 2012 Share Posted October 22, 2012 928mb approaching the benchmark as a hybrid system. Link to comment Share on other sites More sharing options...
DopplerWx Posted October 23, 2012 Share Posted October 23, 2012 00z GFS is another fish. EDIT: Almost a direct hit to Bermuda though as a ~965mb cane Link to comment Share on other sites More sharing options...
Jmister Posted October 23, 2012 Share Posted October 23, 2012 Adding to the ensemble thing, there was a significant shift west in all but maybe 2 GFS ensembles from 00z to 06z this morning. Here is the difference from 00z at 90hr and 06z at 84hr: Link to comment Share on other sites More sharing options...
Ed Lizard Posted October 23, 2012 Author Share Posted October 23, 2012 Post Tropical Sandy may be more exciting than whether a 60 knot storm or 70 knot hurricane passes near Jamaica, but since this could affect the MA, PHL, NYC and SNE subforums, and I can't be expected to read all of them, a little spillover into this thread until this actual approaches nowcast is fine by me. UK Met seems, IMHO, to be leaning towards the non-GFS camp of an eventual phase. I know Josh is a purist, but I was checking the AccuWx 6 hour Euro maps, and if NYC has 50 to 60 mph offshore winds sustained at 10 meters, and the immediate Massachusetts coast has 70 to 80 mph sustained onshore, even he would appreciate the "hawtness" factor of a post tropical Northeast storm Link to comment Share on other sites More sharing options...
MJO812 Posted October 23, 2012 Share Posted October 23, 2012 12z GEFS is way west of the op run. Retrogades the storm back in SNE. Link to comment Share on other sites More sharing options...
baroclinic_instability Posted October 23, 2012 Share Posted October 23, 2012 12z GEFS is way west of the op run. Retrogades the storm back in SNE. Only 4 of the members actually capture Sandy wholesale, another 4-5 develop a secondary near that spot, the rest are solidly OTS with a minor event. A few massive runs in the GEFS skew the mean, really doesn't mean much at all. At this time frame and with such a highly variable set of events which may occur, not uncommon to see large shifts in the ensemble mean itself which means nothing overall. Link to comment Share on other sites More sharing options...
Edge Weather Posted October 23, 2012 Share Posted October 23, 2012 18z NOGAPS hr. 120, 126, 132 Link to comment Share on other sites More sharing options...
DopplerWx Posted October 24, 2012 Share Posted October 24, 2012 GFS takes Sandy further west right off FL eastern coast then takes a right and then hooks her back left into the NE. Link to comment Share on other sites More sharing options...
NCSNOW Posted October 24, 2012 Share Posted October 24, 2012 Link to comment Share on other sites More sharing options...
phil882 Posted October 24, 2012 Share Posted October 24, 2012 Thought I'd split up things a little with Sandy potentially being a big threat to the United States. Post models and medium range thoughts in here! Link to comment Share on other sites More sharing options...
Guest Imperator Posted October 24, 2012 Share Posted October 24, 2012 Hi all, I think it would be helpful for Pro Mets to help explain to weather enthusiasts that have moderate knowledge or less such as myself certain aspects such as Low Pressure system millibar measurement versus real time conditions (i.e. Because a LP System is 960mb doesnt mean that it will contain winds at X MPH or more.) Over the past 24 hours lurking I have seem some individuals on this forum make some rather outlandish and irrational analysis (Roger Smith, for example--no disrespect) of model output. I would appreciate a Pro Met or two providing more clarity and reality over what the various model outputs mean to sensible weather in a particular location...Also, while I understanding there are many younger folk on this forum, I can remember many a noreaster or major snowstorm with sub 980 Low Pressure that were not "catastrophic" Link to comment Share on other sites More sharing options...
DopplerWx Posted October 24, 2012 Share Posted October 24, 2012 Euro is a mid atl hit. Starts out hugging the eastern fl coast then a short jog east over the water then it phases and hits the mid atl @120hrs. Link to comment Share on other sites More sharing options...
phil882 Posted October 24, 2012 Share Posted October 24, 2012 Hi all, I think it would be helpful for Pro Mets to help explain to weather enthusiasts that have moderate knowledge or less such as myself certain aspects such as Low Pressure system millibar measurement versus real time conditions (i.e. Because a LP System is 960mb doesnt mean that it will contain winds at X MPH or more.) Over the past 24 hours lurking I have seem some individuals on this forum make some rather outlandish and irrational analysis (Roger Smith, for example--no disrespect) of model output. I would appreciate a Pro Met or two providing more clarity and reality over what the various model outputs mean to sensible weather in a particular location...Also, while I understanding there are many younger folk on this forum, I can remember many a noreaster or major snowstorm with sub 980 Low Pressure that were not "disasterous" or "catastrophic" I don't really have much time to explain right now, but I'll try to give the short hand version. Winds in the atmosphere are driven by pressure gradients, not just pressure alone. Thus, a very small tightly wound 950 mb tropical cyclone (with a very strong pressure gradient) can category 4 winds when a large tropical cyclone with a broader pressure gradient (ex Irene) can have weaker winds even at the same pressure. As the models forecast Sandy to strike the Northeast coastline, the pressure gradient will be much broader than what you would typically experience with a tropical cyclone. Thus, a 940 mb pressure is not going to pact the same punch as you would experience with a tropical cyclone with a tighter pressure gradient with the same pressure. Link to comment Share on other sites More sharing options...
DopplerWx Posted October 24, 2012 Share Posted October 24, 2012 Link to comment Share on other sites More sharing options...
turtlehurricane Posted October 24, 2012 Share Posted October 24, 2012 Posted my analysis and forecast of Sandy on my blog, going to be exciting to watch this undergo transition into a huge hybrid Nor'easter-hurricane. GFS is coming in line with the ECMWF so I think it's fairly probable at this point. http://weather.schematical.com/ Link to comment Share on other sites More sharing options...
Guest Imperator Posted October 24, 2012 Share Posted October 24, 2012 I don't really have much time to explain right now, but I'll try to give the short hand version. Winds in the atmosphere are driven by pressure gradients, not just pressure alone. Thus, a very small tightly wound 950 mb tropical cyclone (with a very strong pressure gradient) can category 4 winds when a large tropical cyclone with a broader pressure gradient (ex Irene) can have weaker winds even at the same pressure. As the models forecast Sandy to strike the Northeast coastline, the pressure gradient will be much broader than what you would typically experience with a tropical cyclone. Thus, a 940 mb pressure is not going to pact the same punch as you would experience with a tropical cyclone with a tighter pressure gradient with the same pressure. Thanks, I sort of had a grasp of that before. But the running theme here among some seems to be Oh a Cat 4 type non tropical storm is shown on the Euro, therefore we will have a Cat 4 Apocolypse! Ive seen some nasty storms up in the NYC area: Gloria, '85, Halloween '91, December '92 countless blizzars etc. that some people on here may have never experienced, so I understand their hype. However, some education and mentoring would be useful on here to counter the misplaced and skewed analysis by some. Link to comment Share on other sites More sharing options...
Guest Imperator Posted October 24, 2012 Share Posted October 24, 2012 ECMWF looks like Delmarva then an inland runner... Link to comment Share on other sites More sharing options...
phil882 Posted October 24, 2012 Share Posted October 24, 2012 Thanks, I sort of had a grasp of that before. But the running theme here among some seems to be Oh a Cat 4 type non tropical storm is shown on the Euro, therefore we will have a Cat 4 Apocolypse! Ive seen some nasty storms up in the NYC area: Gloria, '85, Halloween '91, December '92 countless blizzars etc. that some people on here may have never experienced, so I understand their hype. However, some education and mentoring would be useful on here to counter the misplaced and skewed analysis by some. While I can't speak for any of the sub-forums, this thread and other threads on the main forum will be heavily moderated in order to prevent misleading or incorrect statements being made about Sandy. Its easy to get excited about a sub 950 hPa storm making landfall in the Northeast, but lets not get carried away with an event that is still 5-6 days away. Link to comment Share on other sites More sharing options...
Guest Imperator Posted October 24, 2012 Share Posted October 24, 2012 While I can't speak for any of the sub-forums, this thread and other threads on the main forum will be heavily moderated in order to prevent misleading or incorrect statements being made about Sandy. Its easy to get excited about a sub 950 hPa storm making landfall in the Northeast, but lets not get carried away with an event that is still 5-6 days away. While the storm can indeed be nasty, is the idea of a <970mb storm that is feeding the hype vs any wind/rain, etc that it could produce? Link to comment Share on other sites More sharing options...
Roger Smith Posted October 24, 2012 Share Posted October 24, 2012 We'll see how irrational my thinking is when the 935 mb low goes past any given weather station or ocean buoy. What I would call "skewed and irratiobnal analysis" is to suggest that the storm depicted on the Euro model will max out at 60 knots. The October 1987 non-tropical storm that blew down half the trees in southern England had a minimum pressure of 957 mbs. The Columbus Day storm in western WA and OR had a minimum pressure in the 950s. The Daniel Defoe storm in 1703 probably never broke 945. As I said earlier, the thought process needs to be clarified. If people are really saying :"I don't believe the models, the central pressure will be 960 mbs and max winds 60 mph" that's fine, but if people are saying "the models are right, a 935 mb low will develop, but winds will not be excessive" then that is just 100% absolutely going to bust. And I'm not the only person saying that, just the only one saying it in this thread. Link to comment Share on other sites More sharing options...
turtlehurricane Posted October 24, 2012 Share Posted October 24, 2012 While I can't speak for any of the sub-forums, this thread and other threads on the main forum will be heavily moderated in order to prevent misleading or incorrect statements being made about Sandy. Its easy to get excited about a sub 950 hPa storm making landfall in the Northeast, but lets not get carried away with an event that is still 5-6 days away. Yup, hopefully in coming days the media communicates that even though the pressure will be at cat 4 levels it will only have cat 1 winds if it made landfall in the northeast, and will not be a typical hurricane. I think it'll probably do more damage than a typical hurricane though if the current favored model scenario happened due to the potential for a huge wind radius. It's going to be a very difficult call for the NHC if it happens, do they let the NWS handle it since it's gonna be mostly non-tropical or will they issue hurricane advisories anyways since it will be partially tropical and have major impacts? Link to comment Share on other sites More sharing options...
CT Rain Posted October 24, 2012 Share Posted October 24, 2012 Yup, hopefully in coming days the media communicates that even though the pressure will be at cat 4 levels it will only have cat 1 winds if it made landfall in the northeast, and will not be a typical hurricane. I think it'll probably do more damage than a typical hurricane though if the current favored model scenario happened due to the potential for a huge wind radius. It's going to be a very difficult call for the NHC if it happens, do they let the NWS handle it since it's gonna be mostly non-tropical or will they issue hurricane advisories anyways? It looks to me as if this storm will be warm core through landfall. WIth that in mind... even though it will have some extra tropical characteristics... and the potential for damage you have to keep it going as a hurricane. You could make an argument that if the 1938 storm passed HSE and was undergoing ET it was no longer a true hurricane but rather a warm seclusion. Link to comment Share on other sites More sharing options...
CT Rain Posted October 24, 2012 Share Posted October 24, 2012 GFS cyclone phase space from Bob Hart at FSU. Link to comment Share on other sites More sharing options...
Dsnowx53 Posted October 24, 2012 Share Posted October 24, 2012 I feel like I should know this, but what in particular about the transition to warm seclusion/asymmetric warm core (as opposed to a cold core) makes it so dangerous? Is it that since it's still technically warm core, it keeps its strong core of winds, but also since it's asymmetric, it has an expanding pressure field and thus an expanding wind field as well? And you're getting the benefits of baroclinic enhancement without the hindrances to the core of winds? Link to comment Share on other sites More sharing options...
LakeEffectKing Posted October 24, 2012 Share Posted October 24, 2012 Updated extended outlook: EXTENDED FORECAST DISCUSSION NWS HYDROMETEOROLOGICAL PREDICTION CENTER COLLEGE PARK MD 326 PM EDT WED OCT 24 2012 VALID 12Z SAT OCT 27 2012 - 12Z WED OCT 31 2012 ...CHANCES INCREASING FOR A MAJOR STORM IMPACTING THE MID ATLANTIC AND NORTHEAST... PRELIMINARY UPDATE... USED THE 00Z/24 GEFS MEAN TO UPDATE THE PRELIMINARY FRONTS AND PRESSURES FOR DAYS 3 THROUGH 7. WITH ALL THE ACTION ALONG THE EAST COAST, THE CENTRAL AND WESTERN UNITED STATES ARE AWASH IN PACIFIC AIR, WITH AN ENSEMBLE MEAN SERVING THOSE REGIONS WELL, CONSIDERING THE INHERENT TIMING ISSUES IN THE MORE OPEN FLOW THERE. THE USE OF THE MEAN FOR THE EAST AND ADJACENT ATLANTIC OCEAN FACILITATES MORE LEEWAY TO ADJUST SANDY'S TRACK AS NEEDED BASED ON LATER FORECASTS FROM THE NATIONAL HURRICANE CENTER, AS WELL AS THE PROBLEMATIC POST-TROPICAL PHASE OF THE CYCLONE. WITH REGARD TO SANDY'S ULTIMATE FATE VIS A VIS THE AMPLIFIED POLAR TROUGH OVER THE EAST, THERE IS INCREASING CONSENSUS AMONG THE GUIDANCE FROM THE VARIOUS MODELING CENTERS, PARTICULARLY WITH REGARD TO THE WHOLE OF THE INDIVIDUAL ENSEMBLE MEMBERS. THE DETERMINISTIC SOLUTIONS, IN THE CASE OF THE 00Z/23 GFS AND GEM GLOBAL, ARE OUTLIERS TO THE MAJORITY OF THEIR ENSEMBLE BROTHERS AND SISTERS, WITH THE LION'S SHARE OF THE ENSEMBLE GUIDANCE INDICATING A WHOLESALE INCORPORATION OF SANDY'S POST-TROPICAL CIRCULATION INTO THE UPPER VORTEX CLOSING OVER THE CONTINENT. THE ENTIRE ATLANTIC BASIN SEEMS DESTINED TO BECOME DOMINATED BY BLOCKY HIGHS AND LOWS, WITH DECREASING WIGGLE ROOM FOR EVEN LARGE FEATURES LIKE SANDY. THE BLOCKING IS KEY TO THE OPPORTUNITY FOR THE INTERACTION BETWEEN THE ATLANTIC STORM OF TROPICAL ORIGIN AND THE NORTH AMERICAN VORTEX OF POLAR ORIGIN. SOME OF THE MORE AGGRESSIVE DETERMINISTIC MODELS THAT SPIN UP A TREMENDOUSLY DEEP SURFACE LOW BACK ALONG THE MID ATLANTIC COAST AND LONG ISLAND INCLUDE THE 00Z/24 ECMWF, 00Z/24 NOGAPS, AND 06Z/24 GLOBAL HURRICANE MODEL. IF IT BECOMES CLEARER WITH THE ADVENT OF THE 12Z/24 GUIDANCE THAT A LARGE HYBRID LOW IS LIKELY DAY 6, WILL ADJUST THE FINAL PROGS TOWARD A DETERMINISTIC SOLUTION, WHICH WOULD ROUND THE CIRCULATION OF THE MANUAL FORECAST AND DEEPEN THE PRESSURE SIGNIFICANTLY. THE LUNAR CYCLE WILL PROVE TO BE A FACTOR IN THE POTENTIAL FOR COASTAL FLOODING, WITH HIGH TIDES MOST ANOMALOUS FROM THAT EFFECT ALONE SUNDAY THROUGH TUESDAY AFTER THE FULL MOON ON SUNDAY. FINAL... MADE ONLY MINOR MODIFICATIONS TO THE UPDATE PACKAGE FOR THE FINAL ISSUANCE. TWO OF THE DETERMINISTIC MODEL HOLDOUTS FOR A CONSOLIDATED EAST COAST STORM FROM THE 00Z/24 CYCLE, THE GFS AND GEM GLOBAL, SWITCHED TO THE MERGER CAMP FOR THE 12Z/24 RUN, ALBEIT FARTHER NORTH THAN THE PREFERRED CLUSTER. THE 12Z/24 GEFS MEAN TRENDED DEEPER THAN THE 00Z/24 VERSION, WITH A GREATER NUMBER OF WOUND-UP MEMBERS, CENTERED OVER NEW YORK CITY ON THE MORNING OF DAY 6. THE 12Z/24 ECMWF TRACKS SANDY WEST OF THE BOTH THE NATIONAL HURRICANE TRACK AND THE BULK OF THE GUIDANCE IN THE EARLY PART OF THE SHORT RANGE, ALLOWING THE CIRCULATION TO BE CAPTURED BY THE AMPLIFYING TROUGH SOONER, ALONG THE ATLANTIC COAST OF THE DELMARVA PENINSULA DAY 5. THE PARTICULARS OF THE SENSIBLE WEATHER DEPEND VERY MUCH ON THE LATITUDE AT WHICH THE ANTICIPATED MERGER TAKES PLACE- A POINT TO BE REFINED IN THE COMING DAYS. IN GENERAL, EXPECT HEAVY RAIN AND HIGH WINDS CLOSE TO WHERE THE POST-TROPICAL CORE OF SANDY TRACKS, WITH HEAVY SNOWS IN A CRESCENT ON THE SOUTHWEST EDGE OF THE MERGED VORTEX. THE BEST BET FOR SUBSTANTIAL ACCUMULATIONS WILL BE OVER THE CENTRAL APPALACHIANS, THOUGH EVEN ADJACENT LOWER ELEVATIONS OVER THE UPPER OHIO VALLEY AND EAST OF THE MOUNTAINS COULD SEE MEASURABLE SNOW. CISCO Link to comment Share on other sites More sharing options...
thegreatdr Posted October 24, 2012 Share Posted October 24, 2012 I posted this on facebook...and it is worth repeating here. It is my opinion that whichever model "scores" a 100 hPa error in the surface pressure pattern near the East coast/Western Atlantic with this system within 180 hours should never, ever be run again, for any reason. This includes the HWRF and GFDL. Models which forecast below 940 hPa stand a real chance at reaching this point of futility. Link to comment Share on other sites More sharing options...
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