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hurricane sandy thread #2


forkyfork

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Only has about 3" for the area. The heaviest qpf is going to be to the west and south of the center but the euro could easily be underdoing qpf

There would likely be intense convective bands to the east of the center and the steady blob of rain to the west/south. Hard to say how this will all shake out.

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do these types of storms carry with them the risks of tornado outbreaks we usually see with landfalling hurricanes??

there was one a couple of miles east of us during Irene... good thing we had power so had access to radar and news and all that stuff... having no power while thinking of hurricanes must be really scary...violin.gif

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75-85 mph winds.

Thanks. Very impressive. Time for everyone who still has any doubts of this storm's seriousness outside of our little community here to really start taking this seriously. Sustained hurricane force winds with possible category 2 type gusts are for the most part not manageable in this region of the country especially if the duration is 12 hours or more and people who don't understand that are going to be in for a rude awakening.

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do these types of storms carry with them the risks of tornado outbreaks we usually see with landfalling hurricanes??

there was one a couple of miles east of us during Irene... good thing we had power so had access to radar and news and all that stuff... having no power while thinking of hurricanes must be really scary...violin.gif

low tornado threat at this moment according to the SPC:

DAY 4-8 CONVECTIVE OUTLOOK

NWS STORM PREDICTION CENTER NORMAN OK

0401 AM CDT FRI OCT 26 2012

VALID 291200Z - 031200Z

...DISCUSSION...

...DELMARVA...

HURRICANE SANDY IS EXPECTED TO BE DRAWN NWWD TOWARD THE DELMARVA

EARLY NEXT WEEK...PARTLY IN RESPONSE TO APPROACHING UPPER TROUGH AND

STUBBORN DOWNSTREAM BLOCK. IF THE TROPICAL SYSTEM MOVES INLAND A

STRONG PRESSURE GRADIENT COULD LEAD TO POTENTIALLY DAMAGING SFC

WINDS...ESPECIALLY ALONG THE NRN PERIPHERY OF LOW WHERE ONSHORE FLOW

WILL BE MAXIMIZED. HOWEVER...POOR INSTABILITY SHOULD LEAD TO

MINIMAL TSTM ACTIVITY AND FOR THIS REASON WILL NOT INTRODUCE AN

ORGANIZED SEVERE EVENT AT THIS TIME. IF IT BECOMES CLEAR THAT

SUFFICIENT INSTABILITY WILL SUPPORT ORGANIZED DEEP CONVECTION THEN A

SEVERE RISK WILL BE INTRODUCED.

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Updated consensus track is now shifted 30 south Asbury Park with (gulp) min pressure 943 mb possibly 3h prior.

GEM solution needs to be adjusted west at 36-48h, I suspect, but may otherwise be fairly good guidance on the capture scenario. Deep vortex of hurricane is pulled west to merge with expanding vortex of the frontal wave, explosive cyclogenesis develops Monday, warm seclusion continues in part due to topographic nesting, system spins at a violent rate and hits the coast. This is looking almost inevitable now.

From now to landfall I will make a pledge to discuss only weather impacts, damage can be inferred etc.

During the latter stages of approach a triple point is likely to form near the Hudson canyon ocean buoy moving north towards ISP. This will be the focus for violent squally thunderstorms embedded in the veering (NE to ESE) surface flow at 50-80 mph with higher gusts developing. Meso-scale complexes of thunderstorms will likely then wrap around the centre as it approaches the north-central Jersey coast. These could be aligned something like LGA to Staten Island to Asbury Park before landfall moving west. Damaging wind gusts may be embedded with these. Further west the frontal merge process will be setting up the M front (the wrap around will be effectively the P front) north-south approximately central line of NJ into Catskills. This will become the focus for 2-3" per hour rainfalls for as long as the setup persists, squeezing hard so it doesn't move west with the system. Therefore some huge rainfall totals could develop in n/c and nw NJ and ne PA.

Long Island Sound in this scenario would see the developing occlusion edging north adding gustiness to a general 50-80 mph wind field that could contain gusts to 100 or even 120 mph. Wind fields could pulsate due to interaction of the pressure system with the nearby topographic barriers. Higher exposed parts of the Berkshires could see 150 mph gusts. Any communication facilities at high elevation or on top of NYC buildings are at risk due to higher wind speeds at what amounts to 900 mbs. Planning should no doubt address removal of anything that can be removed from high exposed locations.

Wind speeds will drop off slightly into land areas west of Manhattan but probably not quite enough to avoid hurricane gusts. Near the landfalling center, whether my consensus track is right or maybe too far north, wherever that is, a small nearly calm center will persist even after landfall. It won't necessarily be an eye, but a zone of < 25 mph winds lasting an hour or so (perhaps longer if the center stalled). This could confuse some members of the public and tempt them out into harm's way. The system will retain some similarity to a hurricane in that the peak winds could be at eyewall distance then a flat gradient of wind speeds and perhaps local streaks of wind max over exposed terrain on the forward side.

In the consensus and GFS-GEM scenario, winds south of about central NJ will start out NNW 30-50 mph Monday, increase to perhaps NW 40-70 mph then W 50-80 mph tapering off gradually south down the coast but at a very gradual pace. There could be embedded wrap around squalls near the center. The arctic air in any scenario will likely not intrude on the center at any point and the arctic front is likely to be washed out by downsloping. Modified arctic air will wrap around and form a pseudo-front aligned to the center like a reverse letter C extending into the Atlantic but stalling as the system drags it west while it tries to rotate.

Snow will break out later Sunday at about 1200' and higher in PA, MD and WV and then may come down to valley floor elevations but I doubt that it will snow more than a trace in BWI or PHL in any scenario (of course less likely in the Euro landfall). Snow amounts could be 15-35 inches but may be banded like lake effect. Great Lakes regions will see mixed precip developing with soft hail or ice pellets in lake effect streamers.

Returning to NYC, the landfall period will basically be a land hurricane situation, wind gusts could exceed record values. By the time the low is in n/c NJ or ne PA, winds in NYC and Long Island will be SSE 45-75 mph with some higher gusts, trending to 35-60 mph in e CT and RI. It now looks more likely that a loop will be avoided and the low will track steadily NW and NNW out of the region, thus winds will just slowly abate to 30-50 mph SW with temperatures falling into the 40s F.

These are observations one might expect to see in the course of the landfall for JFK ...

Note: times in GMT (z) subtract 4h for EDT ...

Monday 18z ... 69/69 ... R+ ... NNE 48G78 (mph)

Monday 21z ... 72/72 ... TRW+ R++ ... NE 65G90

Tuesday 00z ... 71/71 ... TRW+R++ ... E 70G102

Tuesday 03z ... 64/64 ... TRW+RW ... SE 74G110

Tuesday 06z ... 61/60 ... RW- LTNG W-N ... SSE 55G78 (possible surge in vicinity)

Tuesday 09z ... 57/55 ... RW ... S 47G70

Tuesday 12z ... 55/52 ... R- SSE 40G57

Meanwhile at landfall n/c NJ observers might find this hourly sequence ...

62/62 ... T+R+ NNE 60G92

63/62 ... TRW N 40G70

67/64 ... LTNG NNW 25G45

spec ... 67/62 S 15G27 moon visible

70/70 ... TRW+ SSE 30G50

71/71 ... TRW SSE 60G90

70/68 ... RW S 65G100

(then 3h int to

65/60 ... SSW 50G80

57/54 ... SSW 48G70

wind subsides slowly as center fills inland but remnant gusts could increase against that trend for a time.

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Is anyone else concerned about Sandy's landfall timing? NHC has her making landfall late on Monday night, although some models already bring her onshore by Monday evening. I don't know all of the significant hurricanes in the region so I don't know if there is a slow bias with the forecast timing of the hurricane, but I do know that the 1938 LI Express and Irene were faster than expected.

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So all in all.. Everyone should begin to prepare for possibly a life-altering event.. This storm is going to be studied and talked about for years if these models are at all correct..

Is anyone actually a little nervous? I'm usually not, but w/ this type of event.. I'm getting a little ancy...

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Pretty dumb move on their part. Public won't care about a High Wind Warning or Storm Warning.

Not to mention that their 5 AM track still maintains it as a tropical entity until after landfall. People would assume "high winds" to be like the 40-50 MPH wind events we get during winter storms with only 2 feet of storm surge. However, in this case, some models are depicting that some areas may experience sustained hurricane-force winds of 75 MPH with gusts up to 90 MPH, along with surges possibly exceeding 10 feet.

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Under Flood and High Wind Watch right now, saying 4 to 8" possible but probably closer to 4" in central nj, winds 35-45 mph with gusts up to 65 mph which sounds about right. I feel winds could be even stronger than that for a time Monday, probably 50-60 mph sustained, gusts near or up to hurricane force but that will get adjusted as we go through today and early Sunday.

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If central jersy winds are forcast to gust to 65 that would mean that they would most likely be less as you head North into long islamd no. Also I really doubt the public is going to take this seriously ESP if there just goimg to issue a wind watch and flood watch say for gust to 65 like central jersy is saying. that to the public is just another storm that we get all the time they might take it a litt more seriously if nhc was handling tje storm the whole way up the coast witch truly they should simce it's technically still going to be tropical in nature also they might take it more seriously if they didn't see a forcast for say central jersy witch is closer to the storm saying wimd gist will gust to 65 again there goimg to say that happens everytime we get a big stor, so its no big deal I wish there was a consensus of all forcasters instead of everyone giveimg diff wind forcast some say 65 as top gust some are saying over a 100 that is a big diff when talking about weather the public is going to take somethimg serious or not some people even on the board prob aren't really takeing it seriously couse nobody is giveimg ome soid forcast yet and yes I understand it's 3 days out but still!!!

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Exactly hailstorm and who do you listen to when preparing the forcast calling for a wind event that we get all the time or the one calling for hurricane force winds?? What's your best educated guess for the NYC metro long island area wind focast????

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Upton is being very bearish with the forecast storm surge of only 2 feet for NY harbor in their Coastal Flood Watch.

I think they are working with the Mayor's OEM. Bloomberg as usual wishes to secretly flee city on weekends and is having the NWS play this thing down to give him cover/excuse if he does decide to leave a 'capable' deputy mayor in charge!

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The GFS easterly LLJ north of the center is the strongest that I can remember seeing here.

I found a March 2010 sounding to compare it to at around 400-600 meters up.

March 2010

948 472 6.6 6.0 96 0.6 6.3 93 64 284.1 285.1 281.8 301.3 6.19

Sandy

900 570 15.0 14.6 98 0.4 14.7 75 101 296.9 299.0 291.9 330.7 11.68

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Snipet from NHC 8am public adv. Even if Sandy landfalls south we will still see very strong winds. Anyone who is saying a landfall south would have less of an impact here is not correct.

SANDY IS A VERY LARGE TROPICAL CYCLONE. HURRICANE FORCE WINDS EXTEND

OUTWARD UP TO 100 MILES PRIMARILY SOUTHWEST OF THE CENTER...AND

TROPICAL STORM FORCE WINDS EXTEND OUTWARD UP TO 450 MILES...

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I have to agree with you guys. The wording by Mt. Holly on the high wind warning is borderline irresponsible IMO. Given that you are at the least supposed to have a 50 KT extratropical cyclone slamming into central Jersey, to put in you wording all the way down to the coast 35-45 MPH sustained winds is horrendous. Makes it sound like a fairly run of the mill storm when that is not the case in any way.

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