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Hurricane Sandy - LIVE - Meteorological Discussion


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doesnt that just mean right now? im not sure it means they wont ever.

No, that means as long as Sandy is alive. See following quote from Mt Holly AFD this morning:

SANDY: FOR LATEST ADVISORIES/TRACK-INTENSITY/CONE OF WIND

PROBABILITIES AND EVENTUALLY PSURGE...PLS FOLLOW NHC PRODUCTS.

SINCE THERE WILL LIKELY BE AT LEAST A PARTIAL TRANSITIONING TO A

POWERFUL EXTRA TROPICAL CYCLONE...ALL HAZARDS FOR THE MOUNT HOLLY

AREA WILL BE GENERATED USING STANDARD NON TROPICAL PROCEDURES.

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No, that means as long as Sandy is alive. See following quote from Mt Holly AFD this morning:

SANDY: FOR LATEST ADVISORIES/TRACK-INTENSITY/CONE OF WIND

PROBABILITIES AND EVENTUALLY PSURGE...PLS FOLLOW NHC PRODUCTS.

SINCE THERE WILL LIKELY BE AT LEAST A PARTIAL TRANSITIONING TO A

POWERFUL EXTRA TROPICAL CYCLONE...ALL HAZARDS FOR THE MOUNT HOLLY

AREA WILL BE GENERATED USING STANDARD NON TROPICAL PROCEDURES.

If they're gonna drop Sandy as a tropical cyclone, which they technically should from a scientific perspective, they might as well do it now since this has become more nor'easter than hurricane already. It's already more baroclinic than a sub-tropical cyclone in my opinion, though I guess there's little baroclinicity in the low levels thus far so that could be their reasoning.

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Amazing to watch the outflow being sucked into the jet stream, high speed ventilation highway http://mapmaker.aos....g8visflash.html

Pretty amazing. It's definitely getting the best of both worlds (ET and Trop.) with regards to forcing for vertical motion. Amazing that the warm core has strengthened considerably this morning.

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If they're gonna drop Sandy as a tropical cyclone, which they technically should from a scientific perspective, they might as well do it now since this has become more nor'easter than hurricane already. It's already more baroclinic than a sub-tropical cyclone in my opinion.

agree with you. It appears to be interacting with the frontal boundry as we type. As you mentioned, that outflow into the jetstream is WOW, and likely a major cause of the deepening this morning. I can't imagine what the dynamics will be like when it gets further north and receives two left exit and two right entrance regions.
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Pretty amazing. It's definitely getting the best of both worlds (ET and Trop.) with regards to forcing for vertical motion. Amazing that the warm core has strengthened considerably this morning.

Having a way to really move the air out of the top of the storm efficiently is typically just as much a hallmark of any strong tropical system so it should be no surprise that being able to do that extremely well via the help of the jet stream has enhanced Sandy.

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Divergence is rapidly decreasing at the moment. Shear still looks pretty good though.

What data are you basing that on? 300 hPa divergence on the SPC mesoanalysis has been increasing the past 6 hours. The jet stream is projected to intensify throughout the day too, from 120 to 150 kt at the 200 hPa level.

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I will start trying to archive some of the satellite image products. I am not sure that there is a way for amateurs to find good satellite images after they are cycled out of their respective loops... so lots of information is lost to us. It's ok but everyone can have insights from the professional level down to amateurs and youth.

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1-3 feet of surge from Florida to the Carolinas currently, with the highest surge at Fernandina beach on the FL/GA border http://tidesandcurre...data/SANDY.html

Surge forecast from the NHC:

FL EAST COAST NORTH OF CAPE CANAVERAL...1 TO 2 FT

NC SOUTH OF SURF CITY...1 TO 3 FT

NC NORTH OF SURF CITY INCLUDING PAMLICO/ALBERMARLE SNDS...3 TO 5 FT

SE VA AND DELMARVA INCLUDING LOWER CHESAPEAKE BAY...2 TO 4 FT

UPPER CHESAPEAKE BAY...1 TO 2 FT

OCEAN CITY MD TO THE CT/RI BORDER...4 TO 8 FT

LONG ISLAND SOUND...RARITAN BAY...AND DELAWARE BAY...4 TO 8 FT

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1-3 feet of surge from Florida to the Carolinas currently, with the highest surge at Fernandina beach on the FL/GA border http://tidesandcurre...data/SANDY.html

Surge forecast from the NHC:

FL EAST COAST NORTH OF CAPE CANAVERAL...1 TO 2 FT

NC SOUTH OF SURF CITY...1 TO 3 FT

NC NORTH OF SURF CITY INCLUDING PAMLICO/ALBERMARLE SNDS...3 TO 5 FT

SE VA AND DELMARVA INCLUDING LOWER CHESAPEAKE BAY...2 TO 4 FT

UPPER CHESAPEAKE BAY...1 TO 2 FT

OCEAN CITY MD TO THE CT/RI BORDER...4 TO 8 FT

LONG ISLAND SOUND...RARITAN BAY...AND DELAWARE BAY...4 TO 8 FT

I wonder what they're forecasting for NYC? 4-8ft? I guess that falls in the MD to RI guidline but then again so does LI sound.

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I think it's similar to what was predicted for Irene last year. Although we have a full moon now. Irene came during a worse Spring Tide.

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Although the exact magnitude of this storm system is not known yet, we should try to save satellite image products; there are not any water vapor image archives that i know of that can be accessed. Even for important weather systems, these images are usually lost once they are cycled out of their respective java or flash loops.

I have saved all of these images in png format, here is an animation that I hope to try and have show multiple days. vrfssh.gif

Are others who have time interested in saving the step by step images from different satellite imagery?

Even just a few hours or a day's worth will leave AmWX and other interested amateur/professional forums an archive of image data that would otherwise not exist.

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Pressure has risen to 962 mb, up from the lowest pressure of 957 mb 6 hours ago. I don't think weakening was projected but then again 6 hours is such a short period it could easily not show up on the global models. I'm not using any of the hurricane models because this is far from a tropical cyclone. I'll be surprised if the pressure doesn't begin to fall in the next 6 hours.

Temperature only 3 °C warmer in the eye than the environment, so the warm core is weakening. Convection needs to fire near the center to strengthen the warm core and restart intensification.

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Pressure has risen to 962 mb, up from the lowest pressure of 957 mb 6 hours ago. I don't think weakening was projected but then again 6 hours is such a short period it could easily not show up on the global models. I'm not using any of the hurricane models because this is far from a tropical cyclone. I'll be surprised if the pressure doesn't begin to fall in the next 6 hours.

Temperature only 3 °C warmer in the eye than the environment, so the warm core is weakening. Convection needs to fire near the center to strengthen the warm core and restart intensification.

So what happens if it makes the extratrop transition too early?

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Although the exact magnitude of this storm system is not known yet, we should try to save satellite image products; there are not any water vapor image archives that i know of that can be accessed. Even for important weather systems, these images are usually lost once they are cycled out of their respective java or flash loops.

I have saved all of these images in png format, here is an animation that I hope to try and have show multiple days.

Are others who have time interested in saving the step by step images from different satellite imagery?

Even just a few hours or a day's worth will leave AmWX and other interested amateur/professional forums an archive of image data that would otherwise not exist.

I put this together using data from NRL. Warning: 27 mb.

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looking at the visible loop for the last couple hours it appears the LLC "shed" something, for lack of a better term

what is that circular cloud mass (at higher height) that is sorta "shed" a couple hours ago and rotates more NNE

is that displacement of a LLC/MLC or something, seems to co-incide with a 5mb pressure rise

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I think it's similar to what was predicted for Irene last year. Although we have a full moon now. Irene came during a worse Spring Tide.

People need to stop comparing this to irene. There is very little similarity other than the fact that they are both tropical systems making landfall around NYC. As of right now, the storm surge forecast for the battery is 5.6ft. The max surge for irene was 4.1ft. The highest water level was 9.4ft. This time around were talking close to 11ft. That is a huge difference when water was only a half a foot from coming over the sea wall. Plus if this worst case scenario track verifies, surge will probably be on the higher end of the forecast (7-8ft). Obviously things can change but at this juncture this looks like an historic surge for lower manhattan

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Sandy is still being affected by strong wind shear (>30 kts) and very dry air associated with an incipient dry slot and jet streak in the south and east portions of the central circulation. Short range model guidance unanimously shifts this feature to the east over the next 12 hours and allows mid-level the moisture envelope around the center to recover. It also appears that wind shear will be on the decrease in the short term, possibly allowing some redevelopment of convection near the center.

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HURRICANE SANDY DISCUSSION NUMBER 22

NWS NATIONAL HURRICANE CENTER MIAMI FL AL182012

500 PM EDT SAT OCT 27 2012

FIRST A NOTE ON THE NWS WARNING STRATEGY FOR SANDY. IN ORDER TO

AVOID THE RISK OF A HIGHLY DISRUPTIVE CHANGE FROM TROPICAL TO

NON-TROPICAL WARNINGS WHEN SANDY BECOMES POST-TROPICAL...THE WIND

HAZARD NORTH OF THE TROPICAL STORM WARNING AREA WILL CONTINUE TO BE

CONVEYED THROUGH HIGH WIND WATCHES AND WARNINGS WARNINGS ISSUED BY

LOCAL NATIONAL WEATHER SERVICE OFFICES.

SATELLITE IMAGERY SHOWS THAT DRY MID-LEVEL AIR HAS WRAPPED AROUND

THE WESTERN AND SOUTHWESTERN PORTIONS OF THE CIRCULATION...WHICH MAY

HAVE CAUSED THE RECENT WEAKENING OF THE INNER-CORE CONVECTION. THE

AIR FORCE AIRCRAFT MADE ITS FINAL PASS THROUGH SANDY AROUND 1800

UTC AND REPORTED A MINIMUM PRESSURE OF AROUND 961 MB. WIND DATA

FROM THE AIRCRAFT AND A RECENT DROPSONDE FROM THE NOAA G-IV AIRCRAFT

CONDUCTING A SURVEILLANCE MISSION AROUND SANDY SUPPORT MAINTAINING

THE INITIAL INTENSITY OF 65 KT.

THERE HAS BEEN NO CHANGE TO THE TRACK OR INTENSITY FORECAST

REASONING. SANDY IS LIKELY TO REMAIN AT OR NEAR HURRICANE STRENGTH

DURING THE NEXT DAY OR SO. AFTER THAT TIME...THE CYCLONE WILL

INTERACT WITH A STRONG SHORTWAVE TROUGH AND ASSOCIATED COLD FRONT

MOVING INTO THE EASTERN UNITED STATES. AS THIS OCCURS...THE GLOBAL

MODELS INDICATE THAT THE CYCLONE WILL STRENGTHEN DUE TO BAROCLINIC

PROCESSES...AND THE OFFICIAL FORECAST CALLS FOR SOME INCREASE IN

INTENSITY IN A COUPLE OF DAYS. BY 48 HOURS...THE GFS AND ECMWF

MODELS SHOW COLDER AIR WRAPPING AROUND THE SOUTH PORTION OF THE

CIRCULATION AND SANDY IS LIKELY TO HAVE COMPLETED ITS

TRANSFORMATION TO A VIGOROUS EXTRATROPICAL CYCLONE AT THAT TIME.

AFTER LANDFALL...THE CYCLONE IS FORECAST TO STEADILY WEAKEN.

THE GFS AND ECMWF MODELS ARE IN BETTER AGREEMENT THIS AFTERNOON...

WITH THE ECMWF A LITTLE NORTH OF ITS PREVIOUS TRACK. SANDY IS

FORECAST TO MOVE NORTHEASTWARD DURING THE NEXT 24 HOURS...THEN TURN

NORTHWARD AHEAD OF THE APPROACHING MID-LATITUDE TROUGH. THE CYCLONE

SHOULD TURN NORTHWESTWARD...THEN WESTWARD AS IT ROTATES AROUND THE

EASTERN SIDE OF THE DEEPENING TROUGH. ONCE AGAIN...DRAWING A

STRAIGHT LINE BETWEEN THE 48- AND 72-HOUR FORECAST POINTS DOES NOT

QUITE DEPICT HOW CLOSE THE CENTER IS EXPECTED TO COME TO LONG

ISLAND. HAVING SAID THAT...IT IS STILL TOO SOON TO FOCUS ON THE

EXACT TRACK...BOTH BECAUSE OF FORECAST UNCERTAINTY AND BECAUSE THE

IMPACTS ARE GOING TO COVER SUCH A LARGE AREA AWAY FROM THE CENTER.

FORECAST POSITIONS AND MAX WINDS

INIT 27/2100Z 30.2N 75.2W 65 KT 75 MPH

12H 28/0600Z 31.5N 73.8W 65 KT 75 MPH

24H 28/1800Z 33.4N 72.1W 65 KT 75 MPH

36H 29/0600Z 35.4N 71.1W 65 KT 75 MPH

48H 29/1800Z 37.9N 72.0W 70 KT 80 MPH...POST-TROP/EXTRATROP

72H 30/1800Z 40.0N 77.0W 50 KT 60 MPH...POST-TROP/EXTRATROP

96H 31/1800Z 42.5N 76.5W 35 KT 40 MPH...POST-TROP/EXTRATROP

120H 01/1800Z 45.5N 74.5W 30 KT 35 MPH...POST-TROP/EXTRATROP

$$

FORECASTER BROWN

post-32-0-47135800-1351371581_thumb.gif

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