CFHC Talkback For News Story #44:
Newest Talkback: 10:12 PM 08-09 EDT

Tropical Depression #4 Forms off our Coast
11:08 AM EDT - 09 August 2000

Tropical Systems are known to be sometimes surprising...

This is a quick update to let you know that Tropical Depression 4 has indeed formed. Info now suggests that it may not landfall, however the weak steering winds and very slow movement make any such discussion dangerous. One model has it basically stalling just off the coast, and forming into Hurricane status, but staying OFFSHORE. However, it is much too early to be jumping to conclusions, as it is now just a weak surface low/depression. Until convection fires, this is pure speculation. The fact that it is currently drifting adds questions, and I'm doubting it getting much stronger than it currently is. But, it's worth noting.

Ugh, this one is going to be hard to watch being so close. NHC suggests that it may eventually move NE away from land before ever making landfall. Will it get close enough for us to see some effects? Probably, but nothing major. This is open for debate here.

We will post more as things come in.

Comments? Use the comment button by the story Headline.

Nice Satellite Image of Atlantic (IR Colorized)

Satellite images at: [N.A. visible] (visible -- Daytime Only) [N.A. infrared] (infrared), and [N.A. water vapor] (water vapor)--Nasa source.

Some Forecast models: (NGM, AVN, MRF, ECMWF, ETA)
DoD weather models (NOGAPS, AVN, MRF)
AVN, ECMWF, GFDL, NOGAPS, UKMET

- [mac]

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Displaying Talkbacks #6 - #26 (of 26 total)
NWS/TALLAHASSEE (#6)
Posted by: Colleen Location: Lakeland, Florida
Posted On 11:40AM 09-Aug-2000 with id (QURNQVSNRPWNVW*)

Clyde: I think this is what you were talking about, I was able to get into the site, although I will tell you it has been difficult all morning:

FXUS62 KTAE 091436
AFDTLH
AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE TALLAHASSEE FL
1040 AM EDT WED AUG 9 2000

ATTM FORECAST ON TRACK WITH OVERALL 30-40% POP COVERAGE OVER CWA. WILL SEE SEA BREEZE PENETRATION INHIBITED A BIT THIS AFTERNOON WITH
NW-N FLOW. SOUNDINGS CONTINUE TO HAVE LIS OF -5 TO -8...CAPES IN 3K RANGE...& PRECIP WATER VALUES OF AROUND 1.7 INCHES. WILL HAVE TO WATCH ENERGY NOW PUSHING INTO EASTERN GA WITH FLOW TO TAKE NEAR CWA THIS LATE AFTERNOON & THIS EVENING. RUC HAS THIS FEATURE & 700MB FLOW TO BRING IT SW. VISUAL SATELLITE IMAGERY HAS TD#4 WELL PLACED
OFF EAST FL COAST WITH WEST DRIFT INDICATED. HOWEVER MODELS NOT PICKING IT UP WELL...WITH EVEN ETA TAKING IT WELL N & WITH ONLY PIECE OF ENERGY POSSIBLE OVER CENTRAL FL. CURRENT TRENDS SHOULD TAKE IT OVER CENTRAL FL THEN INTO GULF NEXT 24-36 HRS. 12Z RUNS SHOULD BE BETTER. WILL ONLY TWEAK FORECAST ATTM. RECORD IN TLH IS 98 TODAY SO
NEAR RECORD WORDS LOOK GOOD.

Hope this helps: even the NWS forecasters don't have much faith in the models!!!

Clyde (#7)
Posted by: Colleen Location: Lakeland, Florida
Posted On 11:42AM 09-Aug-2000 with id (QURNQVSNRPWNVW*)

Great minds think alike!!! LOL!!!
TD4 (#8)
Posted by: Bubba Location: Yeehaw Junction, Fl
Posted On 11:50AM 09-Aug-2000 with id (QSRNQUXNQUYNQRV*)

I think it'll rain some myself.
Watches (#9)
Posted by: alan Location: orlando
Posted On 12:25PM 09-Aug-2000 with id (RPVNRQUNRRQNRUR*)

Does it surprise anyone else that there hasn't been at least a tropical storm watch issued for the east coast of Florida. After all, the strike probabilities place an 18 percent chance of land fall at Fort Pierce and a 16 at Cocoa over the next 24 hours. The only higher places are to the west northwest of the storm's current location.
If it doesn't go north like the NHC believes, there could be a lot of people caught off guard if a strong tropical storm comes ashore during the middle of the night.
Alberto (#10)
Posted by: Chris
Posted On 01:05PM 09-Aug-2000 with id (RPTNRPQNXTNQ*)

Can someone explain in detail(i.e. not reiterate the NHC discussion) why Alberto is going to make a turn to the north. Just 2 days ago the 48 hr forecast was turning it west after the sheer died down.
TD Four Comments (#11)
Posted by: JJ
Posted On 01:27PM 09-Aug-2000 with id (RPUNQXXNQYYNQYW*)

Somebody asked why the NHC hasn't issued a TS watch for the FL east coast. Probably because they doubt it will reach TS strength or threaten the coast within 24 hours. They're probably fairly confident that its quasi-stationary status will keep it still long enough for the expected trough to pick it up. An 18% chance isn't much at all.

The trough pick-up isn't so clear to me...this is
a pretty shallow system; perhaps there's a *small*
chance it could slip under the trough. If the convection fires up more, however, things will get a little more concrete. Still, track forecasting isn't my forte--I'll go by the NHC's party line for now.
Lows (#12)
Posted by: Duncan Mitre Location: Winter Park, FL
Posted On 01:44PM 09-Aug-2000 with id (RPWNSPNWTNQXR*)

This thing is basically a surface feature. The vis pics still show it moving west now.



Latest Recon ... Either NHC messed up coordinates or storm has moved South (#13)
Posted by: OrlandoDude Location: O-Town
Posted On 03:26PM 09-Aug-2000 with id (QYRNQRXNQSSNVX*)

The latest recon is back and it appears as of 2:35 PM today the storm is located at 27.54 and 77.53 with Surface winds of 35 KTs. It appears either the storm has drifted South or the NHC did not have a good fix on the system and this is an adjustment. Either way, there maybe a rethinking of their 11 AM Forecast.

Here is the recon report if you need assistance decoding this click on this link: http://cirrus.sprl.umich.edu/wxnet/hurricane/recon.txt



803
URNT12 KNHC 091835
VORTEX DATA MESSAGE
A. 09/1835Z
B. 27 DEG 54 MIN N
77 DEG 53 MIN W
C. NA
D. 35 KT
E. 315 DEG 10 NM
F. 050 DEG 39 KT
G. 315 DEG 07 NM
H. EXTRAP 1010 MB
I. 23 C/ 369 M
J. 25 C/ 356 M
K. 24 C/ NA
L. NA
M. NA
N. 12345/1
O. 0.1/1 NM
P. AF966 0204A CYCLONE OB 03
MAX FL WIND 39 KT NW QUAD 1832Z. SLP EXTRAP FROM 1500FT.
WEAK BANDING EVIDENT ON RADAR W-N-NNE SEMICIRCLE 35NM DIA

=


Thanks OralndoDude (#14)
Posted by: Bob H Location: Sanford, FL
Posted On 03:34PM 09-Aug-2000 with id (RPYNQQTNRPQNQSX*)

Your on top of things OrlandoDude thanks!
Good Job!! (#15)
Posted by: Colleen Location: Lakeland, Florida
Posted On 03:40PM 09-Aug-2000 with id (QURNQVSNRQSNUT*)

Thanks for posting the latest recon info...Bob H is right...you are right on top of things!!!
Supplemental recon (#16)
Posted by: Bill
Posted On 03:44PM 09-Aug-2000 with id (RPTNQQPNRQTNYT*)

Some supplemental recon data appears to show 40 kt winds, not sure at surface or FLevel.

RE: Location: the position was given in minutes and seconds. Seems to be just about where it was before, unless I read the report wrong.

Seems like the convection is getting thicker, the organization continues very good. As the recon noted, banding features are showing up on radar.

On another front...has Alberto slowed down and moved more west? seems to be getting better organized too.

Convection seesm to be organizing in the tropical low to the east of TD#4 . NHC has tasked a recon to invest off Cape Hatteras tomorrow. Noted a large flare up on the south end of the wave too, this may be interfering with TD #4.

Finally, there seems to be quite an increase in convection in NW Caribbean.

Finally, finally...seems like the wave off Africa is trying to form a circulation also.

Busy days ahead!

IHS,

Bill

Clearly, it is a tropical storm (was yesterday too, even stronger then). The question is, will NHC upgrade it 'officially'?

IHS,

Bill
Correct Coordinates (#17)
Posted by: Ed Dunham Location: Melbourne, FL
Posted On 03:49PM 09-Aug-2000 with id (VSNQVRNRRVNTT*)

The RECON coordinates were correct. The aircraft fixed the center at 27 degrees and 54 minutes north latitude. 54 minutes equals 9/10 of a degree, so the reported latitude was 27.9 degrees. Ditto for the longitude, i.e., 77 degrees and 53 minutes west longitude equals 77.9 degrees. To convert the 'minutes' reported by the RECON, divide the number by 6, i.e., if the aircraft reports 78 degrees and 18 minutes, divide the 18 by 6 = .3, or in this example, 78.3 degrees. Very much enjoy the dialogue at this site - some of you have some excellent ideas.
Cheers,
Ed Dunham, Chief Meteorologist (Retired)
40 Knot Winds (#18)
Posted by: Duncan Mitre Location: Winter Park, FL
Posted On 03:52PM 09-Aug-2000 with id (RPWNSPNWTNQUR*)

Does this mean, for all practical purposes, that we have a Beryl?


Beryl? (#19)
Posted by: Bill Location: Tallahassee
Posted On 04:07PM 09-Aug-2000 with id (RPTNQQPNRQTNYT*)

Duncan-

yes, it does. And the latest HIRES VIS pics show the convection increasing near the center, and wrapping around, so it looks like we may have Beryl on our hands eventually, possibly at 5. If NHC doesn't upgrade, that will not be a solely weather based decsion, it seems. I think they will upgrade.

Mr. Dunham, thank you for that explanation, as I said, it didn't look like it had moved much to me (did rough calculation of minutes and seconds in head). It does seem in the last couple of pics to be drifting west again, tho.

IHS,

Bill

Beryl (#20)
Posted by: Colleen Location: Lakeland, Florida
Posted On 04:10PM 09-Aug-2000 with id (QURNQVSNRQSNUT*)

Ed, maybe you can correct me if I am wrong, but I believe in regards to Duncan's question, if the winds are 35knts at surface level, that would indicate a TS...because I believe that at flight level, those winds would be reported as "FLIGHT LEVEL" which could be as high as 10,000ft and not really do justice to the actual winds at the surface. Is that correct? MAX FL WIND 39 KT NW QUAD 1832Z. SLP EXTRAP FROM 1500FT.
WEAK BANDING EVIDENT ON RADAR W-N-NNE SEMICIRCLE 35NM DIA

So what would this tell us? That it is still at TD level? Thanks for your help in explaining all this!!!!

Regards, Colleen
Colleen's question (#21)
Posted by: Bill
Posted On 04:33PM 09-Aug-2000 with id (RPTNQQPNRQTNYT*)

Pardon me for jumping in Colleen-

the answer to your question is that, all other things being equal, if there are 35 kt surface winds, it is a tropical storm. It is the surface winds that "count" in this regard. Flight level winds as you indicated, can be high above the surface and indicate the relative strength of the storm as well, but in a different context. Many storms, especially after landfall (Fran comes to mind) were still hurricanes (in terms of windspeed)above the boundary (near surface) layer, but at the surface, the system was a tropical storm. That is what the NHC goes by as far as classification is concerned...surface (actually 10 meter/33 ft) wind speed. There can be other factors too, as in the winds must be sustained. (I minute avg I believe). Gusts do not a hurricane make. Gordon had gusts to 127 mph at Gitmo..but it was only a tropical storm (and the gusts were realted to a mesocyclone in the storm circulation).

Now, just because there is a report of 35 kt winds at the surface (35kts=39 mph, threshold for ts formation), NHC doesn't have to say .."aha, tropical storm!". They could disregard it as an isolated observation, or one in error. They could hold off due to lack of convection, or a perceived weakening trend beginning instead of strengthening, or , of course, for other reasons only they know.

Seems to me with an increase of convection near the center, and 35 kt surface winds, plus pressure same or lower, they would upgrade. But, they may wait one advisory to see if the storm holds together. When they say 'tropical storm' everything moves up another notch.

Interestingly, as a side note, some of the models make the storm a hurricane just off NE Florida in 72 hours. NHC is disregarding that at this time, basically because htis is such a weird little system.

Sorry fot the long answer..probably more than you wanted to know!

IHS,

Bill
Thanks (#22)
Posted by: Duncan Mitre Location: Winter Park, FL
Posted On 04:37PM 09-Aug-2000 with id (RPWNSPNWTNRX*)

So it's borderline. Guess we'll find out in about a half hour.

Thanks!
Well it's still a depression (#23)
Posted by: Duncan Mitre Location: Winter Park, FL
Posted On 04:43PM 09-Aug-2000 with id (RPWNSPNWTNRX*)

At least the new advisory says so. It's probably close, though, guys. Thanks again.
NHC (#24)
Posted by: peanuts Location: Hollywood, FL
Posted On 04:45PM 09-Aug-2000 with id (VSNSPNQYTNRUP*)

Well the 5pm report is out and no change in status I guess we will just have to wait and see
TD 4 (#25)
Posted by: Bill Location: Tallahassee
Posted On 05:00PM 09-Aug-2000 with id (RPTNQQPNRQTNYT*)

As Duncan said, still a 'td'..thought it interesting the NHC discussion mentioned the FLevel winds but NOT the surface. They state that they aren't going to upgrade until consistent convection shows up. I understand their point but think they are being too technical.

We'll see what 11pm brings, however, unless convection really fires this evening, NHC will hold off until at least 5 am, maybe 11am, tomorrow.If it does recurve, looks like it is going to get pretty close in before it recurves!

Time will tell..it always does!

See you all tomorrow. Thanks to the C brothers and
all of you for a great forum!

IHS,

Bill
On Alert? (#26)
Posted by: Richard B (http://www.atlantic-technologies.co.uk) Location: Gloucester, England, UK
Posted On 06:12PM 09-Aug-2000 with id (RQRNQSYNTUNRRV*)

Well this depression, which insidently hasdformed from the Bermuda Low i said we needed to be watching for the past 8 days, looks to me like it is doing its own thing! It is drifting, and is such a small system i think it could go pretty much where it wants. I do see an upgrade to Tropical Storm Beryl, probably tomoro, because the system is slowly becoming better organised. And as it is only 100 miles off the east coast you all in that area should watch closely. At the moment i have issued aTropical Depression Watch from my site, but i think i may need to upgrade it to a Tropical Storm Watch, or even Warning, within 24 hours... any way i am so busy at the moment so i must go. Keep watching this one closely and i will talk to you all soon.
Take care.
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