Invest 98L in Western Atlantic

[NDG]

Nothing new, the NHC's "testing phase" continues, j/k

TROPICAL WEATHER DISCUSSION
NWS TPC/NATIONAL HURRICANE CENTER MIAMI FL
805 AM EDT SUN JUL 29 2007
...SPECIAL FEATURE...
SURFACE TROUGH IS LOCATED FROM 29N71W TO 23N74W. ENVIRONMENTAL
CONDITIONS ARE FORECAST TO BECOME MORE FAVORABLE FOR TROPICAL
CYCLONE DEVELOPMENT AS THE SYSTEM MOVES NNE OVER THE NEXT DAY OR
TWO. SCATTERED SHOWERS AND TSTMS ARE LOCATED FROM 25N-30N E OF
TROUGH TO 70W.

http://www.nhc.noaa.gov/text/refresh/MIATWDAT+shtml/291048.shtml?

[NDG]

Starting to look better, it seems to be that windshear is only 10-15 kts

[Tampa Bay Hurricane]

I think a tropical depression is likely in the
next 1-2 days as the NHC says conditions will
be favorable and it looks much more
organized this morning.

[tailgater]

Shear still looks like it's pretty strong(shear)on WV loop , and center(low level twist) may be exposed later this morning. But then again NHC is saying conditions becoming more favorable, so lets see if Chantal can form and become a fish. Oops sorry Bermuda.

[tailgater]

QS pass 10:38 UTC shows broad surface circulation near 29N 72W which may not be entirely closed. Winds are very light on west side:

http://manati.orbit.nesdis.noaa.gov/dat ... MBas19.png

This chart shows a fairly well organized LLC trying to form. @ 29N 72 W
Along with some fairly strong winds away from center.

[NDG]

After looking at the first 1 km vis sat loops, at the surface this is not as organized as I thought it was, most of the convection is away from the broad low.

[wxman57]

Here's a current (13Z) surface analysis with 1K satellite overlay. I've identified a mid-level vorticity center near 28N/70W. No clear signs of an LLC. No ships anywhere near the area, so we won't get any surface data today - not until it passes Bermuda. May give Bermuda a little rain as it passes, but doesn't appear to be any significant threat to the island. Can't see a need for recon as it's heading out to sea at a faster clip now. I didn't see any 12Z models in my email. was curious as to where the NHC would initialize them.

Well, I'm burning daylight now. Going to head out on the bike for a ride. We didn't get in from last evening's ride until 10pm last night.

[Berwick Bay]

The system looks somewhat better organized this morning as it heads out into the open Atlantic. Who knows, perhaps by tomorrow we may have a depression. Regardless, I don't believe that this was "another test invest" or some such nonsense. I believe that NHC forecasters, after studying all of the pertinent info, assigned both this and the last system invest status because they genuinely believed that the systems deserved it. Also, it is true that the NHC has had its share of problems lately, but I still believe that there's enough credibility within the organization not to designate phony invests as we approach the heart of the season. My God, models are calling for potential development in the GOM next week as we enter the month of August. At any given point in the season tropical cyclone formation is always a very problematic thing, but to question the NHC's assigning of the invest status to given weather systems strikes me as arrogant at best and downright irresponsible at worst.

[wxman57]

Model data just in. 30.1/72.7 for initialization at 12Z.

TROPICAL CYCLONE GUIDANCE MESSAGE
NWS TPC/NATIONAL HURRICANE CENTER MIAMI FL
1353 UTC SUN JUL 29 2007

DISCLAIMER...NUMERICAL MODELS ARE SUBJECT TO LARGE ERRORS.
PLEASE REFER TO NHC OFFICIAL FORECASTS FOR TROPICAL CYCLONE AND SUBTROPICAL CYCLONE INFORMATION.

ATLANTIC OBJECTIVE AIDS FOR

DISTURBANCE INVEST (AL982007) 20070729 1200 UTC

...00 HRS... ...12 HRS... ...24 HRS. .. ...36 HRS...
070729 1200 070730 0000 070730 1200 070731 0000

LAT LON LAT LON LAT LON LAT LON
BAMS 30.1N 72.7W 31.7N 72.2W 33.1N 71.4W 34.3N 69.8W
BAMD 30.1N 72.7W 32.0N 71.5W 34.1N 69.7W 36.4N 67.3W
BAMM 30.1N 72.7W 31.8N 71.8W 33.5N 70.5W 35.2N 68.3W
LBAR 30.1N 72.7W 32.2N 71.5W 34.5N 70.1W 37.0N 68.4W
SHIP 20KTS 24KTS 31KTS 39KTS
DSHP 20KTS 24KTS 31KTS 39KTS

...48 HRS... ...72 HRS... ...96 HRS. .. ..120 HRS...
070731 1200 070801 1200 070802 1200 070803 1200

LAT LON LAT LON LAT LON LAT LON
BAMS 35.4N 67.7W 38.3N 60.7W 41.7N 50.5W 43.8N 35.8W
BAMD 38.7N 64.5W 44.6N 57.2W 52.2N 45.8W 58.1N 38.1W
BAMM 37.0N 65.6W 41.6N 58.2W 47.7N 46.0W 55.0N 31.9W
LBAR 39.4N 66.0W 44.8N 57.3W .0N .0W .0N .0W
SHIP 46KTS 54KTS 53KTS 46KTS
DSHP 46KTS 54KTS 53KTS 46KTS

...INITIAL CONDITIONS...
LATCUR = 30.1N LONCUR = 72.7W DIRCUR = 10DEG SPDCUR = 12KT
LATM12 = 27.3N LONM12 = 73.2W DIRM12 = 10DEG SPDM12 = 12KT
LATM24 = 25.3N LONM24 = 73.8W
WNDCUR = 20KT RMAXWD = 30NM WNDM12 = 20KT
CENPRS = 1009MB OUTPRS = 1012MB OUTRAD = 150NM SDEPTH = M
RD34NE = 0NM RD34SE = 0NM RD34SW = 0NM RD34NW = 0NM

[wxman57]

And here's a current surface analysis with indications of where the NHC initialized 98L and where I can see a mid-level spin:

[NDG]

This is where I see the broad furface low and the MLC on vis loop.

[tailgater]

May bad guys and gals, I meant to post this chart,
http://manati.orbit.nesdis.noaa.gov/img ... ap?457,202
I think it will get more attention on the next TWO.

[NDG]

May bad guys and gals, I meant to post this chart,
http://manati.orbit.nesdis.noaa.gov/img ... ap?457,202
I think it will get more attention on the next TWO.

That seems to be correct, right about where I see the broad low turning around 29N & 71.5W on vis sat.

[NDG]

And here's a current surface analysis with indications of where the NHC initialized 98L and where I can see a mid-level spin:

Well, the models were initialized wrong then because there's definitely nothing turning at 30.2N/72.8W, rotation is to the SE of this location.

[HURAKAN]

Statement as of 11:30 am EDT on July 29, 2007

For the North Atlantic...Caribbean Sea and the Gulf of Mexico...

The area of low pressure...located about 400 miles northeast of
the central Bahamas...has not become any better organized this
morning. This system still has some potential for tropical or
subtropical development over the next day or two as it moves
north-northeastward at 10 to 15 mph.
Elsewhere...tropical cyclone formation is not expected during the
next 48 hours.
$$

Forecaster Rhome

It seems RECON is not going.

[cycloneye]

NOUS42 KNHC 291500
WEATHER RECONNAISSANCE FLIGHTS
CARCAH, NATIONAL HURRICANE CENTER, MIAMI, FL.
1100 AM EDT SUN 29 JULY 2007
SUBJECT: TROPICAL CYCLONE PLAN OF THE DAY (TCPOD)
VALID 30/1100Z TO 31/1100Z JULY 2007
TCPOD NUMBER.....07-067

I. ATLANTIC REQUIREMENTS
1. NEGATIVE RECONNAISSANCE REQUIREMENTS.
2. OUTLOOK FOR SUCCEEDING DAY.....NEGATIVE.
3. THE INVEST SCHEDULED FOR 29/2000Z WAS CANX BY
NHC AT 29/1430Z.


Recon Cancelled.

[Tampa Bay Hurricane]

It looks better organized...
Recon not going? Oh well that's why I'm an
amateur.

[HURAKAN]

It LOOKS better, there is no thought about it, but structurally, it's not better organized. If this was HOLLYWOOD, we would already have at least a depression, but since we don't work with looks, it's still a disturbance.

[Tampa Bay Hurricane]

oh ok...intriguing....wow forecasting this stuff is really
tricky...

[HURAKAN]

That's why QuikSCAT is so important, looks can be really deceiving. Remember Claudette back in 2003, it looked like a tropical storm, but it was really still a wave.