Ken711 wrote:After landfall, what is the expected track, N, NW or W?
eventually N-NW
ATL: SANDY - Remnants - Discussion
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Weatherguy173
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Re:
eventually N-NW
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Nothing I say is intended to be a forecast; it's only food for thought and friendly advice!
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Aric Dunn
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melbourne airport just had a gust to 56mph. sustained at 41mph
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Space & Atmospheric Physicist, Embry-Riddle Aeronautical University,
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GoneBabyGone
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Re: ATL: SANDY - Hurricane - Discussion
What is the significance of it having really low pressure? In other words, what is that shorthand for in a practical sense? How does that make the storm more dangerous -- which aspects does it affect?
Thanks!
Thanks!
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SouthernBreeze
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Re: Re:
Ken711 wrote:After landfall, what is the expected track, N, NW or W?
I was just looking at a couple models that show it going inland NW a short ways, then looping around SW.....
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Houstonia
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Re: ATL: SANDY - Hurricane - Discussion
Harris County (Houston) Flood Control District met Jeff Lindner is very excited:
Potentially historic and unprecedented hurricane potential for the NE US coast.
Over the next 5 days a set of extraordinary meteorological factors will come together to potentially produce a hurricane impact on the NE US coast that has never before been experienced since the founding of this nation and the keeping of written weather records.
In response to this potential threat, all US weather balloon sounding stations are launching upper air balloons every 6 hours to incorporate the latest data into the forecast models in support of NHC and HPC forecasting operations…this has never happened before!
The following discussion will attempt to explain this complex set of parameters for what appears to be an increasing likely extremely high impact but never before seen event!
Background:
Hurricanes striking the NE US are not overly uncommon…just last year Irene moved into the same area causing extensive damage and the area which has one of the longest periods of recorded weather history anywhere in the US has been hit several times before by hurricanes. To understand what is forecasted to take place this weekend and early next week, one must look at the fundamental differences between what is called a tropical cyclone…hurricane and what is called post tropical (extra-tropical). To simplify, a tropical cyclone is warm core with no surface temperature gradients (same air mass before and after passage) and they gain intensity from warm waters below. Post tropical (extra-tropical) as usually system higher in latitude than tropical cyclones that do have temperature gradients (cold and warm fronts) and gain intensity not so much from warm water, but the differences in those temperature gradients and jet stream dynamics aloft. Many times as tropical cyclones move out of the tropics and northward into the higher latitude they encounter increasingly colder air masses that wrap into the system and the transition begins from tropical (warm core) to post tropical or cold core (with fronts). An example of a type of extra-tropical system would be a nor’easter.
Upper Air Pattern for this Event:
The upper air pattern over North America and over the North Atlantic is becoming increasingly blocked…weather systems such as big high and low pressure centers are slowing down and will become nearly stationary. Massive high pressure is building over Greenland currently while a large longwave trough is developing over the central and eastern US. Due to the high latitude blocking that is going into place these large scale features will remain nearly stationary in place for the next 5-7 days.
The longwave trough currently developing over the eastern US will become increasingly negative titled (oriented NW to SE instead of SW to NE). Most of the time troughs nearing the east coast are positive tilted (SW to NE) and hurricanes to their SE (where Sandy currently is) are steered N and NE out to sea. In fact all hurricanes that have affected the NE US since 1851 have had tracks from the SW to the NE consistent with a SW to SE steering flow. The difference with this event is the downstream blocking high over Greenland which will prevent Sandy from accelerating NE into the Atlantic and also a strong shortwave trough which moves through the large longwave trough and helps to capture Sandy into the trough.
With the trough anchored over the SE US and mid Atlantic producing an increasingly strong SE steering flow and blocking high pressure over Greenland, Sandy has little choice but to turn back toward the NW or even WNW and strike the US coast. A hurricane has never struck the US mid Atlantic or NE coast moving toward the NW or WNW or at a right angle to the coast as Sandy is forecast to do. Historical storms generally move SW to NE parallel to the coast with the greatest impacts offshore or over extreme east MA and Cape Cod.
As far as the models predicted track go, they are doing a good job with a rare pattern with only modest amounts of spread. Generally the ECMWF continues to be on the west and southern edge of the guidance taking Sandy into the southern DELMARVA area while the GFS and CMC are further north into Long Island (NYC) and southern New England. The current NHC forecast track is splitting the difference with slightly more weight toward the ECMWF which was the first model to predict this “highly anomalous event” and has remained very consistent over the past 2-3 days.
Model Intensification (Tropical vs. Post Tropical):
For reference the powerful 1938 Long Island hurricane holds most of the low pressure records over the NE US. A central pressure of 946mb was recorded as this storm moved inland over southern Long Island producing the highest storm surge on record on Long Island and into southern New England. The 1991 “Perfect Storm” had a central pressure of around 972mb which produced significant coastal damage from North Carolina to Maine. I list these benchmark events as comparisons to what the models are showing for Sandy.
Every forecast model except the NAM is forecasting a sub 960mb storm which would be significantly lower than the 1991 event. However most of the model guidance is producing a sub 940mb storm which has never occurred over the NE US before (946mb is the lowest recorded pressure). To understand what this means, the lower the pressure the stronger the storm system…in the tropics such pressures as this would equal to a category 4-5 hurricane. However, it will not be that simple! Sandy is already starting to undergo changes in her internal structure this morning with the inner core winds weakening and the wind field expanding outward a feature closer to a post tropical system (large weaker wind field) than a tropical system (smaller more concentrated wind field). Even if these super low pressure are to verify, the system would not produce category 4-5 winds as the pressure gradient would be spread out of hundreds of miles with a massive area of 70-90mph winds.
The question is why are the forecast models predicting such “historic” low pressures with this event and are they correct?
1) One would expect a true hurricane (tropical cyclone) to weaken as it moves northward into a colder and drier air mass over the NE US and adjacent Atlantic waters. Additionally water temperatures along the track are generally below the threshold needed for tropical cyclone intensification.
2) If the real world data does not support tropical cyclone intensification, then why are the models all showing it? The system is expected to gain more and more extra-tropical features as it moves northward which means it starts to draw its energy sources from temperature gradients and jet stream dynamics instead of the warmer waters. What is likely happening in the models is that the warm and moist influx of Caribbean air with Sandy will greatly intensify the temperature gradient with the SE moving polar air mass from Canada and help intensity the overall storm. Additionally, Sandy’s surface low will be in a favorable region of the trough to provide strong upper level divergence aloft which will help promote intensification.
3) However…what is interesting is that many of the models keep Sandy warm core or tropical toward landfall while intensifying in conditions that would be marginal at best for a tropical cyclone to hold its intensity. It is likely that Sandy will be something of an “in between system” drawing energy initially from the warm Gulf stream below and then more and more from the mid latitude jet and temperature influences.
4) The models could be completely wrong on the pressures (it would not be the first time). However, it must be noted that nearly every model is showing the same very low pressure and that does add credibility to their solutions.
Possible Impacts:
As with any rare weather event the impacts are somewhat of an unknown. Additionally the uncertainty of how Sandy will evolve and how is curves back toward the US coast will drive where and how severe the impacts will be.
It can be easily stated that should the forecast track and models “spectacular” low pressure verify a storm of rare intensity and tremendous impacts will be felt along the NE and mid-Atlantic coast. Given the forecasted perpendicular strike on the coast, onshore winds will push the Atlantic Ocean inland along the New Jersey and New York coast including New York City. Due to the high blocking over Greenland, the fetch of wind will extend nearly across the entire Atlantic Ocean and this will result in massive wave action aimed at the NE US coast. Lunar tides are also near peak with the full moon on Monday and this combined with the wave run-up and long duration of onshore winds (20-30 hours at 60-80mph) will result in potentially record breaking storm surge values. The potential is there for coastal inundation of sea water never before experienced in the NE US including New York City, but this depends heavily on the exact track of the center of Sandy.
Strong winds will batter much of the mid Atlantic and NE for not hours but days as Sandy moves NW to WNW and slows. These winds will last anywhere from 20-30 hours at 60-80mph with higher gust resulting in widespread power outages and downed trees. Strong winds will spread well inland from the coast into Canada and the OH valley.
Rainfall will be extensive as tropical moisture is brought northward with Sandy and pushed against a stalled front nearly along the higher terrain of the Appalachian mountains. Flooding rainfall due to the high rainfall rates and slow storm motion is likely and it is possible some rivers will reach record crests.
Impacts over the open Atlantic will be severe with a massive area of sustained winds of 60-70mph over hundreds of miles. Wave heights will build into the 20-30 foot range and I would not be surprised to see heights build toward 40-45 feet. Visibilities will be reduced to near zero in blowing sea spray and heavy rainfall.
Potential for widespread travel and commerce disruption as air, surface, sea, and rail travel will likely be significantly impacted along with widespread long term power outages which could last well into November.
My words:
I don't think it's too off-topic or politically biased to say this could really affect voter turnouts if it verifies.
Potentially historic and unprecedented hurricane potential for the NE US coast.
Over the next 5 days a set of extraordinary meteorological factors will come together to potentially produce a hurricane impact on the NE US coast that has never before been experienced since the founding of this nation and the keeping of written weather records.
In response to this potential threat, all US weather balloon sounding stations are launching upper air balloons every 6 hours to incorporate the latest data into the forecast models in support of NHC and HPC forecasting operations…this has never happened before!
The following discussion will attempt to explain this complex set of parameters for what appears to be an increasing likely extremely high impact but never before seen event!
Background:
Hurricanes striking the NE US are not overly uncommon…just last year Irene moved into the same area causing extensive damage and the area which has one of the longest periods of recorded weather history anywhere in the US has been hit several times before by hurricanes. To understand what is forecasted to take place this weekend and early next week, one must look at the fundamental differences between what is called a tropical cyclone…hurricane and what is called post tropical (extra-tropical). To simplify, a tropical cyclone is warm core with no surface temperature gradients (same air mass before and after passage) and they gain intensity from warm waters below. Post tropical (extra-tropical) as usually system higher in latitude than tropical cyclones that do have temperature gradients (cold and warm fronts) and gain intensity not so much from warm water, but the differences in those temperature gradients and jet stream dynamics aloft. Many times as tropical cyclones move out of the tropics and northward into the higher latitude they encounter increasingly colder air masses that wrap into the system and the transition begins from tropical (warm core) to post tropical or cold core (with fronts). An example of a type of extra-tropical system would be a nor’easter.
Upper Air Pattern for this Event:
The upper air pattern over North America and over the North Atlantic is becoming increasingly blocked…weather systems such as big high and low pressure centers are slowing down and will become nearly stationary. Massive high pressure is building over Greenland currently while a large longwave trough is developing over the central and eastern US. Due to the high latitude blocking that is going into place these large scale features will remain nearly stationary in place for the next 5-7 days.
The longwave trough currently developing over the eastern US will become increasingly negative titled (oriented NW to SE instead of SW to NE). Most of the time troughs nearing the east coast are positive tilted (SW to NE) and hurricanes to their SE (where Sandy currently is) are steered N and NE out to sea. In fact all hurricanes that have affected the NE US since 1851 have had tracks from the SW to the NE consistent with a SW to SE steering flow. The difference with this event is the downstream blocking high over Greenland which will prevent Sandy from accelerating NE into the Atlantic and also a strong shortwave trough which moves through the large longwave trough and helps to capture Sandy into the trough.
With the trough anchored over the SE US and mid Atlantic producing an increasingly strong SE steering flow and blocking high pressure over Greenland, Sandy has little choice but to turn back toward the NW or even WNW and strike the US coast. A hurricane has never struck the US mid Atlantic or NE coast moving toward the NW or WNW or at a right angle to the coast as Sandy is forecast to do. Historical storms generally move SW to NE parallel to the coast with the greatest impacts offshore or over extreme east MA and Cape Cod.
As far as the models predicted track go, they are doing a good job with a rare pattern with only modest amounts of spread. Generally the ECMWF continues to be on the west and southern edge of the guidance taking Sandy into the southern DELMARVA area while the GFS and CMC are further north into Long Island (NYC) and southern New England. The current NHC forecast track is splitting the difference with slightly more weight toward the ECMWF which was the first model to predict this “highly anomalous event” and has remained very consistent over the past 2-3 days.
Model Intensification (Tropical vs. Post Tropical):
For reference the powerful 1938 Long Island hurricane holds most of the low pressure records over the NE US. A central pressure of 946mb was recorded as this storm moved inland over southern Long Island producing the highest storm surge on record on Long Island and into southern New England. The 1991 “Perfect Storm” had a central pressure of around 972mb which produced significant coastal damage from North Carolina to Maine. I list these benchmark events as comparisons to what the models are showing for Sandy.
Every forecast model except the NAM is forecasting a sub 960mb storm which would be significantly lower than the 1991 event. However most of the model guidance is producing a sub 940mb storm which has never occurred over the NE US before (946mb is the lowest recorded pressure). To understand what this means, the lower the pressure the stronger the storm system…in the tropics such pressures as this would equal to a category 4-5 hurricane. However, it will not be that simple! Sandy is already starting to undergo changes in her internal structure this morning with the inner core winds weakening and the wind field expanding outward a feature closer to a post tropical system (large weaker wind field) than a tropical system (smaller more concentrated wind field). Even if these super low pressure are to verify, the system would not produce category 4-5 winds as the pressure gradient would be spread out of hundreds of miles with a massive area of 70-90mph winds.
The question is why are the forecast models predicting such “historic” low pressures with this event and are they correct?
1) One would expect a true hurricane (tropical cyclone) to weaken as it moves northward into a colder and drier air mass over the NE US and adjacent Atlantic waters. Additionally water temperatures along the track are generally below the threshold needed for tropical cyclone intensification.
2) If the real world data does not support tropical cyclone intensification, then why are the models all showing it? The system is expected to gain more and more extra-tropical features as it moves northward which means it starts to draw its energy sources from temperature gradients and jet stream dynamics instead of the warmer waters. What is likely happening in the models is that the warm and moist influx of Caribbean air with Sandy will greatly intensify the temperature gradient with the SE moving polar air mass from Canada and help intensity the overall storm. Additionally, Sandy’s surface low will be in a favorable region of the trough to provide strong upper level divergence aloft which will help promote intensification.
3) However…what is interesting is that many of the models keep Sandy warm core or tropical toward landfall while intensifying in conditions that would be marginal at best for a tropical cyclone to hold its intensity. It is likely that Sandy will be something of an “in between system” drawing energy initially from the warm Gulf stream below and then more and more from the mid latitude jet and temperature influences.
4) The models could be completely wrong on the pressures (it would not be the first time). However, it must be noted that nearly every model is showing the same very low pressure and that does add credibility to their solutions.
Possible Impacts:
As with any rare weather event the impacts are somewhat of an unknown. Additionally the uncertainty of how Sandy will evolve and how is curves back toward the US coast will drive where and how severe the impacts will be.
It can be easily stated that should the forecast track and models “spectacular” low pressure verify a storm of rare intensity and tremendous impacts will be felt along the NE and mid-Atlantic coast. Given the forecasted perpendicular strike on the coast, onshore winds will push the Atlantic Ocean inland along the New Jersey and New York coast including New York City. Due to the high blocking over Greenland, the fetch of wind will extend nearly across the entire Atlantic Ocean and this will result in massive wave action aimed at the NE US coast. Lunar tides are also near peak with the full moon on Monday and this combined with the wave run-up and long duration of onshore winds (20-30 hours at 60-80mph) will result in potentially record breaking storm surge values. The potential is there for coastal inundation of sea water never before experienced in the NE US including New York City, but this depends heavily on the exact track of the center of Sandy.
Strong winds will batter much of the mid Atlantic and NE for not hours but days as Sandy moves NW to WNW and slows. These winds will last anywhere from 20-30 hours at 60-80mph with higher gust resulting in widespread power outages and downed trees. Strong winds will spread well inland from the coast into Canada and the OH valley.
Rainfall will be extensive as tropical moisture is brought northward with Sandy and pushed against a stalled front nearly along the higher terrain of the Appalachian mountains. Flooding rainfall due to the high rainfall rates and slow storm motion is likely and it is possible some rivers will reach record crests.
Impacts over the open Atlantic will be severe with a massive area of sustained winds of 60-70mph over hundreds of miles. Wave heights will build into the 20-30 foot range and I would not be surprised to see heights build toward 40-45 feet. Visibilities will be reduced to near zero in blowing sea spray and heavy rainfall.
Potential for widespread travel and commerce disruption as air, surface, sea, and rail travel will likely be significantly impacted along with widespread long term power outages which could last well into November.
My words:
I don't think it's too off-topic or politically biased to say this could really affect voter turnouts if it verifies.
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Aric Dunn
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Re: ATL: SANDY - Hurricane - Discussion
GoneBabyGone wrote:What is the significance of it having really low pressure? In other words, what is that shorthand for in a practical sense? How does that make the storm more dangerous -- which aspects does it affect?
Thanks!
lower the pressure higher the winds.
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Note: If I make a post that is brief. Please refer back to previous posts for the analysis or reasoning. I do not re-write/qoute what my initial post said each time.
If there is nothing before... then just ask
Space & Atmospheric Physicist, Embry-Riddle Aeronautical University,
I believe the sky is falling...
If there is nothing before... then just ask
Space & Atmospheric Physicist, Embry-Riddle Aeronautical University,
I believe the sky is falling...
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StormingB81
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I haven't heard this I could have missed it but I am just south of the putter banks....someone said we can expect hurricane force winds here I said you better know what you are talking about cause I haven't heard that yet I have heard 50-60 mph gust but that's it anything different I missed besides all the rain
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GoneBabyGone
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Re: ATL: SANDY - Hurricane - Discussion
Very helpful, Houstonia. Thanks. Do you have a link to that?
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Portastorm
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Re:
StormingB81 wrote:I haven't heard this I could have missed it but I am just south of the putter banks....someone said we can expect hurricane force winds here I said you better know what you are talking about cause I haven't heard that yet I have heard 50-60 mph gust but that's it anything different I missed besides all the rain
Your local NWS forecast suggests wind gusts no higher than 45 mph.
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Any forecasts under my name are to be taken with a grain of salt. Get your best forecasts from the National Weather Service and National Hurricane Center.
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OuterBanker
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Re: ATL: SANDY - Hurricane - Discussion
Latest excerpt from NWS here (Dare co, NC)
.SITUATION OVERVIEW...
HURRICANE SANDY IS FORECAST TO MOVE NORTHEAST AND REMAIN OFFSHORE
OF THE NORTH CAROLINA COAST THIS WEEKEND. DESPITE REMAINING
OFFSHORE IT WILL RESULT IN SIGNIFICANT IMPACTS ALONG COASTAL NORTH
CAROLINA. MODERATE COASTAL FLOODING AND ROUGH SURF WILL DEVELOP
SATURDAY NIGHT AND CONTINUE INTO MONDAY. IN GENERAL...RESIDENTS
SHOULD PREPARE FOR STORM SURGE RESULTING IN INUNDATION OF 3 TO 5
FEET ABOVE GROUND LEVEL ALONG THE SOUTHERN PAMLICO SOUND AND ALONG
THE COAST NORTH OF CAPE LOOKOUT. WINDS OF 30 TO 40 MPH WITH GUSTS
OF 50 TO 60 MPH ARE EXPECTED ALONG THE COAST...OVER THE INLAND
AREAS WINDS OF 15 TO 25 MPH WITH GUSTS TO 35 MPH ARE LIKELY. RAIN
WILL DEVELOP TONIGHT AND CONTINUE INTO MONDAY. RAINFALL AMOUNTS
WILL RANGE FROM 2 TO 4 INCHES INLAND WITH 4 TO 6 INCHES ALONG THE
COAST...LOCAL AMOUNTS TO 8 INCHES WILL BE POSSIBLE. THIS AMOUNT OF
RAIN WILL LIKELY PRODUCE FLOODING OF LOW LYING AND POOR DRAINAGE AREAS.
DANGEROUS RIP CURRENTS WILL DEVELOP THIS AFTERNOON AND CONTINUE
INTO EARLY NEXT WEEK.
If you are south of Lookout it will be less.
.SITUATION OVERVIEW...
HURRICANE SANDY IS FORECAST TO MOVE NORTHEAST AND REMAIN OFFSHORE
OF THE NORTH CAROLINA COAST THIS WEEKEND. DESPITE REMAINING
OFFSHORE IT WILL RESULT IN SIGNIFICANT IMPACTS ALONG COASTAL NORTH
CAROLINA. MODERATE COASTAL FLOODING AND ROUGH SURF WILL DEVELOP
SATURDAY NIGHT AND CONTINUE INTO MONDAY. IN GENERAL...RESIDENTS
SHOULD PREPARE FOR STORM SURGE RESULTING IN INUNDATION OF 3 TO 5
FEET ABOVE GROUND LEVEL ALONG THE SOUTHERN PAMLICO SOUND AND ALONG
THE COAST NORTH OF CAPE LOOKOUT. WINDS OF 30 TO 40 MPH WITH GUSTS
OF 50 TO 60 MPH ARE EXPECTED ALONG THE COAST...OVER THE INLAND
AREAS WINDS OF 15 TO 25 MPH WITH GUSTS TO 35 MPH ARE LIKELY. RAIN
WILL DEVELOP TONIGHT AND CONTINUE INTO MONDAY. RAINFALL AMOUNTS
WILL RANGE FROM 2 TO 4 INCHES INLAND WITH 4 TO 6 INCHES ALONG THE
COAST...LOCAL AMOUNTS TO 8 INCHES WILL BE POSSIBLE. THIS AMOUNT OF
RAIN WILL LIKELY PRODUCE FLOODING OF LOW LYING AND POOR DRAINAGE AREAS.
DANGEROUS RIP CURRENTS WILL DEVELOP THIS AFTERNOON AND CONTINUE
INTO EARLY NEXT WEEK.
If you are south of Lookout it will be less.
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dexterlabio
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This "frankenstorm" thing predicted to become of Sandy reminds me of Orkans in Europe. They are huge non-tropical systems but can bring strong winds as much as 150 mph. The recent Orkan event in Europe AFAIK occurred in 2007 or 2008, not so sure...and I wonder if an Orkan can be compared to Sandy once it merged with the nor'easter and became post-tropical..
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The posts in this forum are NOT official forecast and should not be used as such. They are just the opinion of the poster and may or may not be backed by sound meteorological data. They are NOT endorsed by any professional institution or storm2k.org. For official information, please refer to the NHC and NWS products.
Re: Re:
SouthernBreeze wrote:Ken711 wrote:After landfall, what is the expected track, N, NW or W?
I was just looking at a couple models that show it going inland NW a short ways, then looping around SW.....
That doesn't sound good. I live in Northern Virginia outside of Washington, DC.
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tolakram
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Re: ATL: SANDY - Hurricane - Discussion
latest
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M a r k
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tolakram
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Re: ATL: SANDY - Hurricane - Discussion
higher resolution, from the ftp site
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tolakram
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Re: ATL: SANDY - Hurricane - Discussion
Apologies if this was posted earlier. WU blog entry from Brian Norcross.
The Sandy Paradox
Posted by: Bryan Norcross, 3:38 AM GMT on October 26, 2012
http://www.wunderground.com/blog/bnorcr ... ntrynum=18
Isn't it strange that a hurricane in the Bahamas would somehow turn into a monster mega-storm and slam into the Northeast at the end of October? Aren't hurricanes supposed to weaken as they move north over cold water? What the hell is going on?
The answers are... yes, yes, and we're not completely sure. This is a beyond-strange situation. It's unprecedented and bizarre. Hurricanes almost always bend out to sea in October, although there have been some exceptions when storms went due north, but rarely. No October tropical systems in the record book have turned left into the northeast coast.
The strong evidence we have that a significant, maybe historic, storm is going to hit the east coast is that EVERY reliable computer forecast model now says it's going to happen. The only way we can forecast the weather four or five days days from now is with the aid of these super-complex computer programs run on supercomputers. The two best, the European and the U.S. GFS (Global Forecast System) run by NOAA, are now in reasonable agreement that there IS going to be an extraordinarily unusual confluence of events that results in a massive storm.
The upper-air steering pattern that is part of the puzzle is not all that unheard of. It happens when the atmosphere gets blocked over the Atlantic and the flow over the U.S. doubles back on itself. Sometimes big winter storms are involved.
The freak part is that a hurricane happens to be in the right place in the world to get sucked into this doubled-back channel of air and pulled inland from the coast.
And the double-freak part is that the upper level wind, instead of weakening the storm and simply absorbing the moisture - which would be annoying enough - is merging with the tropical system to create a monstrous hybrid vortex. A combination of a hurricane and a nor'easter.
At least that's what the models are saying. And since all of the independent models are saying something similar, we have to believe them and be ready.
For most people being ready means getting to the store and getting stuff before everybody else gets wise and gets the stuff first. The forecast is for an incredibly widespread and long-duration windstorm, meaning power will likely be out for an extended period of time in a lot of locations.
A transistor radio is your best friend in a situation like this. Get one and enough batteries to keep it going. Your cell phone may or may not be your friend after a big storm.
For people near the coast, it's critical that you pay attention to local evacuation orders and emergency information. This storm, as forecast, will create dangerous and potentially life-threatening storm surge along hundreds of miles of coastline north of where the center comes ashore. Big storms move a lot of water, and this one is about as big as they come.
Right now, it looks like the storm center will land between the Delmarva and New Jersey, which would put the entire Tri-State area of NJ, NY, and Connecticut on the bad side of the storm. The Jersey Shore, Long Island, and New York City itself would be exposed to the brunt of the storm surge due to the "L" in the coastline at NYC. The angle and duration of the wind will keep the water high for an extended period of time, if this comes together as forecast. This means transportation disruptions and widespread coastal damage.
If the storm comes in farther south, the Delmarva, Delaware Bay and maybe the Chesapeake will be at risk. A storm the size that's forecast would cause problems throughout New England as well, even if the center is south of New York. And then there is the threat from flooding rain and the extremely heavy snow well inland.
To make all this worse along the coast, the moon is full on Monday, meaning the high tides will be higher yet.
The hope we have is that the computer models are not handling this unusual situation well, and are predicting a stronger storm than we get. But, we can't bet of it. Even a weaker version will likely mean a nightmare for millions.
The Sandy Paradox
Posted by: Bryan Norcross, 3:38 AM GMT on October 26, 2012
http://www.wunderground.com/blog/bnorcr ... ntrynum=18
Isn't it strange that a hurricane in the Bahamas would somehow turn into a monster mega-storm and slam into the Northeast at the end of October? Aren't hurricanes supposed to weaken as they move north over cold water? What the hell is going on?
The answers are... yes, yes, and we're not completely sure. This is a beyond-strange situation. It's unprecedented and bizarre. Hurricanes almost always bend out to sea in October, although there have been some exceptions when storms went due north, but rarely. No October tropical systems in the record book have turned left into the northeast coast.
The strong evidence we have that a significant, maybe historic, storm is going to hit the east coast is that EVERY reliable computer forecast model now says it's going to happen. The only way we can forecast the weather four or five days days from now is with the aid of these super-complex computer programs run on supercomputers. The two best, the European and the U.S. GFS (Global Forecast System) run by NOAA, are now in reasonable agreement that there IS going to be an extraordinarily unusual confluence of events that results in a massive storm.
The upper-air steering pattern that is part of the puzzle is not all that unheard of. It happens when the atmosphere gets blocked over the Atlantic and the flow over the U.S. doubles back on itself. Sometimes big winter storms are involved.
The freak part is that a hurricane happens to be in the right place in the world to get sucked into this doubled-back channel of air and pulled inland from the coast.
And the double-freak part is that the upper level wind, instead of weakening the storm and simply absorbing the moisture - which would be annoying enough - is merging with the tropical system to create a monstrous hybrid vortex. A combination of a hurricane and a nor'easter.
At least that's what the models are saying. And since all of the independent models are saying something similar, we have to believe them and be ready.
For most people being ready means getting to the store and getting stuff before everybody else gets wise and gets the stuff first. The forecast is for an incredibly widespread and long-duration windstorm, meaning power will likely be out for an extended period of time in a lot of locations.
A transistor radio is your best friend in a situation like this. Get one and enough batteries to keep it going. Your cell phone may or may not be your friend after a big storm.
For people near the coast, it's critical that you pay attention to local evacuation orders and emergency information. This storm, as forecast, will create dangerous and potentially life-threatening storm surge along hundreds of miles of coastline north of where the center comes ashore. Big storms move a lot of water, and this one is about as big as they come.
Right now, it looks like the storm center will land between the Delmarva and New Jersey, which would put the entire Tri-State area of NJ, NY, and Connecticut on the bad side of the storm. The Jersey Shore, Long Island, and New York City itself would be exposed to the brunt of the storm surge due to the "L" in the coastline at NYC. The angle and duration of the wind will keep the water high for an extended period of time, if this comes together as forecast. This means transportation disruptions and widespread coastal damage.
If the storm comes in farther south, the Delmarva, Delaware Bay and maybe the Chesapeake will be at risk. A storm the size that's forecast would cause problems throughout New England as well, even if the center is south of New York. And then there is the threat from flooding rain and the extremely heavy snow well inland.
To make all this worse along the coast, the moon is full on Monday, meaning the high tides will be higher yet.
The hope we have is that the computer models are not handling this unusual situation well, and are predicting a stronger storm than we get. But, we can't bet of it. Even a weaker version will likely mean a nightmare for millions.
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M a r k
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vbhoutex
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Re: ATL: SANDY - Hurricane - Discussion
GoneBabyGone wrote:Very helpful, Houstonia. Thanks. Do you have a link to that?
I can answer for Houstonia since I also am on Jeff's email list. There is not a link to that. Jeff is the Harris County Texas Flood Control Warning Coordinator and Meteorologist. He emails updates etc. to those on the list which is generally in the Houston or at least Texas area. We will be diligent in passing along his updates as they relate to Sandy.
I am beginning to see increased discussion that Sandy may already be starting her transition to Extra-tropical. How could this/would it affect the future track as opposed to her staying tropical almost to landfall?
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Skywarn, C.E.R.T.
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Houstonia
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Re: ATL: SANDY - Hurricane - Discussion
GoneBabyGone wrote:Very helpful, Houstonia. Thanks. Do you have a link to that?
No - it's a private email list.
Oops.. VB already responded.. thanks VB!!
Last edited by Houstonia on Fri Oct 26, 2012 9:29 am, edited 1 time in total.
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Looks like it's losing its southern eyewall.
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Personal Forecast Disclaimer:
The posts in this forum are NOT official forecast and should not be used as such. They are just the opinion of the poster and may or may not be backed by sound meteorological data. They are NOT endorsed by any professional institution or storm2k.org.
Hope this helped
The posts in this forum are NOT official forecast and should not be used as such. They are just the opinion of the poster and may or may not be backed by sound meteorological data. They are NOT endorsed by any professional institution or storm2k.org.
Hope this helped
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cycloneye
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Re: ATL: SANDY - Hurricane - Discussion
The latest HPC discussion:
PRELIMINARY EXTENDED FORECAST DISCUSSION
NWS HYDROMETEOROLOGICAL PREDICTION CENTER COLLEGE PARK MD
952 AM EDT FRI OCT 26 2012
VALID 12Z TUE OCT 30 2012 - 12Z FRI NOV 02 2012
...DANGEROUS HURRICANE/POST-TROPICAL CYCLONE SANDY IS LIKELY TO
SPREAD HIGH WINDS/HEAVY RAINS AND INTERIOR HEAVY SNOWS FROM THE
CAROLINAS AND CENTRAL APPALACHIANS NORTHWARD INTO CANADA...
GENERAL FLOW PATTERN
====================
A RETROGRADING POSITIVE ANOMALY MOVING FROM SOUTHERN GREENLAND
INTO NORTHERN QUEBEC FAVORS A QUASI-STATIONARY DEEP CYCLONE NEAR
THE NORTHEAST, IN THIS CASE HURRICANE SANDY AND ITS POST-TROPICAL
REMAINS. OTHERWISE...RIDGING IS GENERAL EXPECTED OUT
WEST...THOUGH FLOW ACROSS THE PACIFIC IS EXPECTED TO SEND AMPLE
ENERGY/HEAVY PRECIPITATION ACROSS THE NORTHWEST. GUIDANCE IS IN
EXCELLENT AGREEMENT ON THE GENERAL FLOW PATTERN, THOUGH ISSUES
REMAIN WITH SANDY'S FUTURE COURSE AND STRENGTH.
MODEL PREFERENCE
================
THE NATIONAL HURRICANE CENTER (NHC) TRACK NOW BEST RESEMBLES THE
00 UTC ECMWF ENSEMBLE MEAN. THE EXTRATROPICAL TRANSITION OF SANDY
MAY HAVE ALREADY BEGUN BASED UPON RECENT SATELLITE IMAGERY...A
PROCESS EXPECTED TO COMPLETE TUESDAY PER NHC. THE DETERMINISTIC
GUIDANCE (PARTICULARLY THE 00 UTC ECMWF) SHOW PRESSURE SOLUTIONS
WELL BEYOND WHAT HAS EVER BEEN OBSERVED NEAR THE NEW JERSEY/NEW
YORK COAST (EVEN EXCEEDING THE 1938 LONG ISLAND EXPRESS HURRICANE)
EARLY IN THE MEDIUM RANGE PERIOD. THE DETERMINISTIC GUIDANCE
(CANADIAN, GFS, AND ECMWF INCLUDED) HAS SHOWN A VERY STRONG BIAS
WITH TROPICAL CYCLONES GAINING LATITUDE AND/OR TRANSITIONING INTO
NON-TROPICAL STORMS OVER THE PAST COUPLE YEARS... INCLUDING (BUT
NOT EXCLUSIVE TO) LESLIE 2012...ISAAC 2012...DEBBY 2012 IN THE
WESTERN SUBTROPICAL ATLANTIC IRENE 2011 AND IGOR 2010. PLEASE
REFER TO THE NHC FOR UPDATED INFORMATION ON SANDY.
THE 00 UTC ECMWF ENSEMBLE MEAN ALSO DEPICTS AN OVERALL FLOW
PATTERN UPSTREAM ACROSS THE W-CENTRAL CONUS AND ERN PACIFIC THAT
IS ON THE MORE AMPLIFIED AND LESS PROGRESSIVE SIDE OF THE FULL
ENVELOPE OF GUIDANCE SOLUTIONS OVER THE NEXT WEEK. THIS SEEMS
QUITE REASONABLE CONSIDERING DOWNSTREAM BLOCKING.
WEATHER IMPACTS
===============
PER THIS SOLUTION FROM SUNDAY THROUGH WEDNESDAY...WINDS AS HIGH AS
HURRICANE-FORCE ARE EXPECTED TO LASH EXPOSED AREAS OF THE
NORTHEAST/MID-ATLANTIC STATES (THE COAST AND TOPOGRAPHY)...LEADING
TO POTENTIALLY SERIOUS COASTAL EROSION AND COASTAL FLOODING. THE
TIMING OF THE FULL MOON AND THE BUILD-UP OF TIDES OVER MULTIPLE
TIDAL CYCLES SHOULD EXACERBATE THE SITUATION ALONG THE
COAST...PARTICULARLY IN CORNERS SUCH AS THE NEW YORK BIGHT. HEAVY
RAINS ARE EXPECTED TO FOCUS WITHIN SANDY'S WARM CONVEYOR BELT
CIRCULATION AS WELL AS ALONG ITS DRAPING WARM FRONT FROM THE
NORTHERN MID-ATLANTIC STATES AND INTO NEW ENG AND ERN
CANADA...WITH LOCAL AMOUNTS EXCEEDING 10 INCHES POSSIBLE. THIS
SOLUTION WOULD MEANWHILE ALLOW SIGNIFICANT SNOWS WITHIN ITS COMMA
HEAD PATTERN UNDER THE SUPPORTING/COOLING MID-UPPER LEVEL TROUGH
TO FALL AS CENTERED/FOCUSING OVER THE CENTRAL THEN NRN
APPALACHIANS AND VICINITY. LAKE EFFECT SNOWS ACROSS THE EASTERN
GREAT LAKES ARE POSSIBLE THROUGH THE PERIOD WITHIN THE CYCLONIC
FLOW IN THE SYSTEM'S COLD SECTOR. AS THE CYCLONE GRADUALLY WEAKENS
AS IT PULLS NORTHWARD THURSDAY INTO NEXT FRIDAY...WINDS SHOULD
SLACKEN AS SHOULD NERN US PRECIPITATION AMOUNTS/COVERAGE...BUT
EXPECT THAT AMOUNTS WILL REMAIN SIGNIFICANT CONSIDERING TROPICAL
ORIGIN OF THE LOW.
ROTH/SCHICHTEL
PRELIMINARY EXTENDED FORECAST DISCUSSION
NWS HYDROMETEOROLOGICAL PREDICTION CENTER COLLEGE PARK MD
952 AM EDT FRI OCT 26 2012
VALID 12Z TUE OCT 30 2012 - 12Z FRI NOV 02 2012
...DANGEROUS HURRICANE/POST-TROPICAL CYCLONE SANDY IS LIKELY TO
SPREAD HIGH WINDS/HEAVY RAINS AND INTERIOR HEAVY SNOWS FROM THE
CAROLINAS AND CENTRAL APPALACHIANS NORTHWARD INTO CANADA...
GENERAL FLOW PATTERN
====================
A RETROGRADING POSITIVE ANOMALY MOVING FROM SOUTHERN GREENLAND
INTO NORTHERN QUEBEC FAVORS A QUASI-STATIONARY DEEP CYCLONE NEAR
THE NORTHEAST, IN THIS CASE HURRICANE SANDY AND ITS POST-TROPICAL
REMAINS. OTHERWISE...RIDGING IS GENERAL EXPECTED OUT
WEST...THOUGH FLOW ACROSS THE PACIFIC IS EXPECTED TO SEND AMPLE
ENERGY/HEAVY PRECIPITATION ACROSS THE NORTHWEST. GUIDANCE IS IN
EXCELLENT AGREEMENT ON THE GENERAL FLOW PATTERN, THOUGH ISSUES
REMAIN WITH SANDY'S FUTURE COURSE AND STRENGTH.
MODEL PREFERENCE
================
THE NATIONAL HURRICANE CENTER (NHC) TRACK NOW BEST RESEMBLES THE
00 UTC ECMWF ENSEMBLE MEAN. THE EXTRATROPICAL TRANSITION OF SANDY
MAY HAVE ALREADY BEGUN BASED UPON RECENT SATELLITE IMAGERY...A
PROCESS EXPECTED TO COMPLETE TUESDAY PER NHC. THE DETERMINISTIC
GUIDANCE (PARTICULARLY THE 00 UTC ECMWF) SHOW PRESSURE SOLUTIONS
WELL BEYOND WHAT HAS EVER BEEN OBSERVED NEAR THE NEW JERSEY/NEW
YORK COAST (EVEN EXCEEDING THE 1938 LONG ISLAND EXPRESS HURRICANE)
EARLY IN THE MEDIUM RANGE PERIOD. THE DETERMINISTIC GUIDANCE
(CANADIAN, GFS, AND ECMWF INCLUDED) HAS SHOWN A VERY STRONG BIAS
WITH TROPICAL CYCLONES GAINING LATITUDE AND/OR TRANSITIONING INTO
NON-TROPICAL STORMS OVER THE PAST COUPLE YEARS... INCLUDING (BUT
NOT EXCLUSIVE TO) LESLIE 2012...ISAAC 2012...DEBBY 2012 IN THE
WESTERN SUBTROPICAL ATLANTIC IRENE 2011 AND IGOR 2010. PLEASE
REFER TO THE NHC FOR UPDATED INFORMATION ON SANDY.
THE 00 UTC ECMWF ENSEMBLE MEAN ALSO DEPICTS AN OVERALL FLOW
PATTERN UPSTREAM ACROSS THE W-CENTRAL CONUS AND ERN PACIFIC THAT
IS ON THE MORE AMPLIFIED AND LESS PROGRESSIVE SIDE OF THE FULL
ENVELOPE OF GUIDANCE SOLUTIONS OVER THE NEXT WEEK. THIS SEEMS
QUITE REASONABLE CONSIDERING DOWNSTREAM BLOCKING.
WEATHER IMPACTS
===============
PER THIS SOLUTION FROM SUNDAY THROUGH WEDNESDAY...WINDS AS HIGH AS
HURRICANE-FORCE ARE EXPECTED TO LASH EXPOSED AREAS OF THE
NORTHEAST/MID-ATLANTIC STATES (THE COAST AND TOPOGRAPHY)...LEADING
TO POTENTIALLY SERIOUS COASTAL EROSION AND COASTAL FLOODING. THE
TIMING OF THE FULL MOON AND THE BUILD-UP OF TIDES OVER MULTIPLE
TIDAL CYCLES SHOULD EXACERBATE THE SITUATION ALONG THE
COAST...PARTICULARLY IN CORNERS SUCH AS THE NEW YORK BIGHT. HEAVY
RAINS ARE EXPECTED TO FOCUS WITHIN SANDY'S WARM CONVEYOR BELT
CIRCULATION AS WELL AS ALONG ITS DRAPING WARM FRONT FROM THE
NORTHERN MID-ATLANTIC STATES AND INTO NEW ENG AND ERN
CANADA...WITH LOCAL AMOUNTS EXCEEDING 10 INCHES POSSIBLE. THIS
SOLUTION WOULD MEANWHILE ALLOW SIGNIFICANT SNOWS WITHIN ITS COMMA
HEAD PATTERN UNDER THE SUPPORTING/COOLING MID-UPPER LEVEL TROUGH
TO FALL AS CENTERED/FOCUSING OVER THE CENTRAL THEN NRN
APPALACHIANS AND VICINITY. LAKE EFFECT SNOWS ACROSS THE EASTERN
GREAT LAKES ARE POSSIBLE THROUGH THE PERIOD WITHIN THE CYCLONIC
FLOW IN THE SYSTEM'S COLD SECTOR. AS THE CYCLONE GRADUALLY WEAKENS
AS IT PULLS NORTHWARD THURSDAY INTO NEXT FRIDAY...WINDS SHOULD
SLACKEN AS SHOULD NERN US PRECIPITATION AMOUNTS/COVERAGE...BUT
EXPECT THAT AMOUNTS WILL REMAIN SIGNIFICANT CONSIDERING TROPICAL
ORIGIN OF THE LOW.
ROTH/SCHICHTEL
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Visit the Caribbean-Central America Weather Thread where you can find at first post web cams,radars
and observations from Caribbean basin members Click Here
and observations from Caribbean basin members Click Here
Re: ATL: SANDY - Hurricane - Discussion
Shear from S.W side center letting up some, and stronger bands may wrap back around W and SW side center
If so and with land heating over Fl - whole State may feel suprising effects (today -Sat)
http://www.ssec.wisc.edu/data/geo/index ... thod=flash
Not official forecast
If so and with land heating over Fl - whole State may feel suprising effects (today -Sat)
http://www.ssec.wisc.edu/data/geo/index ... thod=flash
Not official forecast
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