Atlantic Invest Thread 2008

[Iceberg]

Recon is showing a TS with (at least to my understanding, closed circulation and falling pressure with a good centre.

Pressure currently at 1008 and sustained winds of 35-40Kt takes it to a TS, my estimation is a early naming before the 10.00pm advisory of a new tropical storm TS FAY.

Edited August 14, 2008 by Iceberg

[londonsnow]

yes ts fay does look like it's on the cards. i dont know how they come up with these names but potential hurricane fay does sound a little wrong. at least gustav is next which sounds a bit better. gusty gustav etc etc.

[Somerset Squall]

NHC reluctant making the upgrade, saying convection is displaced from the centre:

AN AREA OF LOW PRESSURE ASSOCIATED WITH A TROPICAL WAVE IS MOVING

WEST-NORTHWESTWARD AT ABOUT 15 MPH INTO THE VIRGIN ISLANDS. WHILE

THE ASSOCIATED THUNDERSTORM ACTIVITY HAS BECOME MORE

CONCENTRATED...MOST OF THE ACTIVITY IS LOCATED WELL EAST OF THE LOW

CENTER AT THIS TIME. NOAA AND AIR FORCE RESERVE HURRICANE HUNTER

AIRCRAFT ARE CURRENTLY INVESTIGATING THE SYSTEM TO SEE IF A

TROPICAL DEPRESSION HAS FORMED. REGARDLESS OF DEVELOPMENT...THIS

SYSTEM COULD BRING LOCALLY HEAVY RAINS AND GUSTY WINDS TO PORTIONS

OF THE NORTHERN LEEWARD ISLANDS...THE VIRGIN ISLANDS...PUERTO

RICO...AND HISPANIOLA DURING THE NEXT DAY OR TWO...AND INTERESTS IN

THESE AREAS SHOULD MONITOR THE PROGRESS OF THIS SYSTEM.

[Iceberg]

Dvorak has increased to 2.0

To build it up a little more good agreement from GFDL and HWRF. With a whisker from Miami as a possible CAT 4.

[Iceberg]

Good info from Antigua which indicates the closed circulation.

Latest 2 PM (18) Aug 14 80 (27) 77 (25) 29.88 (1012) S 6 light rain showers

1 PM (17) Aug 14 82 (28) 77 (25) 29.88 (1012) SSW 6 showers in the vicinity

Noon (16) Aug 14 80 (27) 77 (25) 29.88 (1012) Variable 1 thunder

11 AM (15) Aug 14 84 (29) 75 (24) 29.88 (1012) ESE 6 light rain showers

[Paranoid]

I don't know how accurate/reliable the CMC models are, but interestingly enough on the last frame of the 12z run it showed what looked like four hurricanes. 3 in the atlantic and one in the GOM

[tinybill]

http://www.nhc.noaa.gov/gtwo_atl.shtml

ZCZC MIATWOAT ALL

TTAA00 KNHC DDHHMM

TROPICAL WEATHER OUTLOOK

NWS TPC/NATIONAL HURRICANE CENTER MIAMI FL

200 PM EDT THU AUG 14 2008

FOR THE NORTH ATLANTIC...CARIBBEAN SEA AND THE GULF OF MEXICO...

1. AN AREA OF LOW PRESSURE ASSOCIATED WITH A TROPICAL WAVE IS MOVING

WEST-NORTHWESTWARD AT ABOUT 15 MPH INTO THE VIRGIN ISLANDS. WHILE

THE ASSOCIATED THUNDERSTORM ACTIVITY HAS BECOME MORE

CONCENTRATED...MOST OF THE ACTIVITY IS LOCATED WELL EAST OF THE LOW

CENTER AT THIS TIME. NOAA AND AIR FORCE RESERVE HURRICANE HUNTER

AIRCRAFT ARE CURRENTLY INVESTIGATING THE SYSTEM TO SEE IF A

TROPICAL DEPRESSION HAS FORMED. REGARDLESS OF DEVELOPMENT...THIS

SYSTEM COULD BRING LOCALLY HEAVY RAINS AND GUSTY WINDS TO PORTIONS

OF THE NORTHERN LEEWARD ISLANDS...THE VIRGIN ISLANDS...PUERTO

RICO...AND HISPANIOLA DURING THE NEXT DAY OR TWO...AND INTERESTS IN

THESE AREAS SHOULD MONITOR THE PROGRESS OF THIS SYSTEM.

2. A BROAD AREA OF LOW PRESSURE IS LOCATED ABOUT 1100 MILES EAST

OF THE LESSER ANTILLES. SHOWER ACTIVITY ASSOCIATED WITH THIS

SYSTEM REMAINS LIMITED AND DISORGANIZED AND DEVELOPMENT...IF

ANY...IS EXPECTED TO BE SLOW TO OCCUR AS THE SYSTEM CONTINUES

MOVING WESTWARD ABOUT 10 TO 15 MPH.

ELSEWHERE.. TROPICAL CYCLONE FORMATION IS NOT EXPECTED DURING THE

NEXT 48 HOURS.

$$

[Iceberg]

I can't say I agree but we are not having a TS tonight. !

DATA FROM NOAA AND AIR FORCE RESERVE HURRICANE HUNTER AIRCRAFT...

ALONG WITH SURFACE OBSERVATIONS AND SATELLITE IMAGERY...INDICATE

THAT THE LOW PRESSURE AREA LOCATED OVER THE VIRGIN ISLANDS HAS NOT

DEVELOPED INTO A TROPICAL DEPRESSION. HOWEVER...UPPER-LEVEL WINDS

ARE BECOMING MORE FAVORABLE FOR DEVELOPMENT...AND A TROPICAL

DEPRESSION COULD FORM AT ANY TIME DURING THE NEXT DAY OR TWO AS THE

SYSTEM MOVES WEST-NORTHWESTWARD ABOUT 15 MPH.DATA FROM NOAA AND AIR FORCE RESERVE HURRICANE HUNTER AIRCRAFT...

ALONG WITH SURFACE OBSERVATIONS AND SATELLITE IMAGERY...INDICATE

THAT THE LOW PRESSURE AREA LOCATED OVER THE VIRGIN ISLANDS HAS NOT

DEVELOPED INTO A TROPICAL DEPRESSION. HOWEVER...UPPER-LEVEL WINDS

ARE BECOMING MORE FAVORABLE FOR DEVELOPMENT...AND A TROPICAL

DEPRESSION COULD FORM AT ANY TIME DURING THE NEXT DAY OR TWO AS THE

SYSTEM MOVES WEST-NORTHWESTWARD ABOUT 15 MPH.

Latest WV shows the best outflow I've ever seen for a non tropical system. !

I do hope this is the right decision as Fay might well be a CAT 4 Hurricane hitting Miami in 5 days time.

[johnholmes]

how on earth can you presume to have a better idea than a 24x7 team of meteorologists whose main task is to check every available item of information and issue their comment?

Apart from this comment I am lost for words!

[Cookie]

how on earth can you presume to have a better idea than a 24x7 team of meteorologists whose main task is to check every available item of information and issue their comment?

Apart from this comment I am lost for words!

he has a special phone line direct to the system. :o

[Somerset Squall]

It's Dolly all over again, looks like a tropical depression, but isn't. NHC obviously couldn't find a closed circulation so there we go, no TD tonight. However, it could form into a tropical depression at any time over the next couple days.

[kold weather]

Yep recon found no closed circulation. Interestingly ther eis still a clear low level circulation and recon whlst not totally closing it up (Hence no upgrade...) did get probably 80% of the way there. Just over the last 2hrs new convection has fired up over the LLC. I think we are seeing some energy transfering from the midlevel circulation to the LLC further west which is a good sign for development.

Looks like LLC is probably about 18N, 64.3W, so not all that far away Puerto Rico from the looks of thing. Seems like its trying to finally get its act on now that the LLC has some decent convection just to the NE which may help tighten it up, tough to say whether it'll do it in time before reaching PR in about 12hrs, even if it doesn't land interaction shouldn't do much harm as the system hasnt got a core to weaken at the moment as its just a mass of thunderstorms with a weak sharp trough which isn't quite closed off.

Should get plenty of information from the islands near to the path of 92L, should be very obvious if a LLC does close off.

Finally, good to see you on this forum John, keep us updated with the people at NOAA say about the steering.

[Iceberg]

how on earth can you presume to have a better idea than a 24x7 team of meteorologists whose main task is to check every available item of information and issue their comment?

Apart from this comment I am lost for words!

Morning john ! (LOL)

Your quite right I can rather speak my own mind.

To be fair though the people at NHC are not right 100% of the time just like the Met office forecasts arn't right 100% of the time.

It's a bit like referee's at the world cup, they seem to get a edict saying a red card from behind is always a red card and so follow this through.

This year the forecasters seem to have a it must have a 100% vertically alined low and mid circulation to be tropical. Yes technically correct, but if you do all this you only end up naming systems which are all perfectly set up.

If a system has good symetrical outflow like that shown by this sytem there is not another explanation for the deriving of it's energy except though a tropical warm core system(hence a tropical depression).

The surface obs strongly indicate a closed surface centre as well.

It's there call at the end of the day though...

[Iceberg]

We've luckily got a fantastic array of bouys etc in the area. They all support and show a N, W, E, S orintation around the main system It's fair to say that a closed centre exists at the surface.(although admittedly the westerly component is weak). Good circulation of the upper precip is evident as well.

The system looks a little bit ragged this morning, outflow is less symetrical, precip is still good but again less structured, Dvorak is still 2.0.

The path has shifted slightly away from Florida and more towards the Carolina's again, although we are talking about a day 5 range. All models make the system a major hurricane by this time, with both HWRF and GFDL making her a CAT 4.

It is very rare indeed for both tropical models to take a non TD system to a CAT 4. Particularly when supported by ships and ECM, the chance of a hurricane remain very high IMO. It's worth mentioning as well that GFDL takes her to a hurricane within 30 hrs.

ships initialised at 30Kt.

To be balanced Doppler is inconclusive about rotation and does not show good banding.

[johnholmes]

I find it fascinating reading this link, its a new area to me so don't get me wrong Ice following my rather acid comment, tks KW, my forecasting never involved anything to do with hurricanes. Although in 1989-90 on Ascension we had 3 US aircraft for several days as they could not get back to their base on Antigua thanks to a very severe hurricane that year. The whole of the US MAC squadron was pulled out of their ahead of it and dispersed further north into the States. No doubt both of you can tell me which one it was.

[Iceberg]

I loved your comment John. :o Tbh it's always good to have a genuine weather forecaster on these threads.

[Iceberg]

She has really taken off in the last hour or so and now looks a right monster.

Doppler support better organisation as well as shown.

[Iceberg]

92L has been increased to T2.5 This is tropical storm strength. I have never know a 2.5 storm that was not being advised on.

[Somerset Squall]

I find it fascinating reading this link, its a new area to me so don't get me wrong Ice following my rather acid comment, tks KW, my forecasting never involved anything to do with hurricanes. Although in 1989-90 on Ascension we had 3 US aircraft for several days as they could not get back to their base on Antigua thanks to a very severe hurricane that year. The whole of the US MAC squadron was pulled out of their ahead of it and dispersed further north into the States. No doubt both of you can tell me which one it was.

Looks like it was monster category 5 Hurricane Hugo John, though it was cat 4 when it hit Antigua.

http://en.wikipedia.org/wiki/Hurricane_Hugo

The name Hugo was retired due to extensive damage and death and was replaced by Humberto, which is still used today.

92L has been increased to T2.5 This is tropical storm strength. I have never know a 2.5 storm that was not being advised on.

Well considering KW estimated the circulation was 80% closed off yesterday then we may see an upgrade later today, a case of wait and see again. The only thing that concerns me is that 92L seems to be taking a more southerly track, right towards Hispaniola it seems, which would greatly dampen development and of course provide flooding to a very vunerable country.

[Iceberg]

The track does worry me, Naming the system would concentrate minds on it's approach. With forecasts making this a possible hurricane in 24 hrs. I would error on the side of caution using the considerably evidence so far.

A Dvorak of 2.5 by the way indicates a CDO has formed around a closed circulation. Dvorak is the world recognised standard for Hurricane intensity. Did the fly pass last night simply miss the full little bit that would have provided the 360 circulation ?.

I hope they name it before an eye appears on doppler.

[Iceberg]

Latest from PR.(Ponce) indicates the closed centre and a probably good guess of minimum pressure which is probably only a 1 or 2 mb lower than that indicated.

Also 20Kt sustained winds being recorded.

4 AM ( Aug 15 77 (25) 75 (24) 29.88 (1011) ESE 14 heavy rain

3 AM (7) Aug 15 80 (27) 73 (23) 29.82 (1009) W 6

2 AM (6) Aug 15 80 (27) 73 (23) 29.82 (1009) WNW 7

[johnholmes]

Looks like it was monster category 5 Hurricane Hugo John, though it was cat 4 when it hit Antigua.

yep that's the one, the most destructive at the time. An article appeared the following year about how much of the overall earth's 'energy' it had 'sucked up' if that is the correct expression! It was either in Weather or the internal Met Magazine in the Met Office.

It was a fascinating time with 15 minute downloads of all the various spectrums on Meteosat, to watch these monster CB's move west out of central Africa, most just slowly dissipated but now and then one would become a hurricane. We had a direct feed from the then Miami Hurricane centre because of the flights west-east and reverse by US MAC aircraft, so it was very interesting reading their technical output.

If memory serves me correctly it was about 3 weeks before they could use the airfield in Antigua after the hurricane.

returning to now, this is the latest NOAA comment on it

SERN CONUS MID LVL DETAILS THAT WILL

INFLUENCE THE TRACK OF A STRONG NRN CARIBBEAN TROPICAL WAVE WHICH

TPC OUTLOOKS INDICATE HAS A HIGH POTENTIAL FOR TROPICAL CYCLONE

FORMATION DURING THE SHORT RANGE PERIOD.

THE EARLY PRELIM FCST MAINTAINS CONTINUITY WITH YDAYS 16Z TPC/HPC

COORDINATION REGARDING A TROPICAL SYSTEM THAT MAY IMPACT PORTIONS

OF THE EXTREME SOUTHEAST NEXT WEEK... WITH MINIMAL MOVEMENT IN THE

DAY 7 EXTRAPOLATION GIVEN LOW CONFIDENCE IN EXACT DETAILS OF THE

ERN RIDGE.

LED TO STARTING THE DAYS 3-7 FCST WITH A 70/30 BLEND

OF THE 00Z GEFS MEAN AND 12Z/14 ECMWF ENSEMBLE MEAN RESPECTIVELY.

ADJUSTMENTS WERE MADE TO ACCOUNT FOR THE POTENTIAL TROPICAL

FEATURE NEAR THE SERN COAST

add to the above, latest recon, if anyone has the code, I used to but have long since lost it.

URNT11 KWBC 150820

97779 08204 60156 64908 37000 16015 06522 /8020

RMK NOAA3 05DDA WAVE OB 17 KWBC

LAST REPORT. ETA TBPB 15/1000Z.

Edited August 15, 2008 by johnholmes

[johnholmes]

the first line tells us its a report for the Atlantic area, and is times at 0820Z

the last tells us he is due in to bermuda at 1000z today

who knows the 2nd and 3rd line decode?

I'm looking stuff up on NOAA but the initial heading is not what they quote, URNT15 is what is should be, so no idea what 11 means, unless its a code to show its not yet been designated a tropical storm?

[kold weather]

Still having a very tough time finding any defined center with this one, clearly got a good Mid level circulation but any LLC must be ill defined at the moment. Dvorak estimates show the center is more to the NE of the massive convective blob and that is where the mid level circulation is, however radar doesn't really suggest anything other then a broad circulation.

Land interaction with Hispaniola looking pretty likely at least for the southern side of the convection, the MLC may end up only skirting land however. Its a tricky one to call because it all depends what area decides to dominate. Right now we have a sort of uneasy truce as the levels still aren't stacked up. Actually land interaction *may* actually help snuff out any vortexes that are further south and finally allow a LLC to drop down from the MLC further north. A great example of that happening was Arlene 2005 I believe, had multiple centers, one went inland over the Yucatan and then a new one popped further east under the mid level circulation over water.

John, it really is an area of weather that can leave everyone totally wrong, including the pros, I think prehaps along with convective forecasting its the toughest of all the areas to forecast because there is just so much uncertainty, countless times have we all been made to look like fools, no matter how much you think you know!

Ps, yep Hugo was a beast, one of the strongest hurricanes to hit as far north as it did, also had mesovortices in its eyewall as well, those are the same thing that did the huge damage when Andrew hit in 1992.

Edited August 15, 2008 by kold weather

[Jack Wales]

I'm surprised this has still not been upgraded, the satellite images have got tropical storm written all over them, then again if there is no LLC or if it's misaligned I can see why nhc are holding out.

Ps, yep Hugo was a beast, one of the strongest hurricanes to hit as far north as it did, also had mesovortices in its eyewall as well, those are the same thing that did the huge damage when Andrew hit in 1992.

Sorry to sound dumb but what are mesovortices?