Disturbance fizzeled in Eastern Atlantic

[Sanibel]

RL3AO might be right and the surface spiral at 30W might actually be the wave axis of this convection.

[RL3AO]

[Gustywind]

[cycloneye]

ABNT20 KNHC 041733
TWOAT
TROPICAL WEATHER OUTLOOK
NWS TPC/NATIONAL HURRICANE CENTER MIAMI FL
200 PM EDT TUE AUG 4 2009

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

DISORGANIZED SHOWERS AND THUNDERSTORMS SEVERAL HUNDRED MILES
SOUTHWEST OF THE CAPE VERDE ISLANDS ARE ASSOCIATED WITH A TROPICAL
WAVE. SIGNIFICANT DEVELOPMENT...IF ANY...OF THE SYSTEM IS EXPECTED
TO BE SLOW TO OCCUR AS THIS WAVE MOVES TO WEST AT ABOUT 15 MPH.
THERE IS A LOW CHANCE...LESS THAN 30 PERCENT...OF THIS SYSTEM
BECOMING A TROPICAL CYCLONE DURING THE NEXT 48 HOURS.

ELSEWHERE...TROPICAL CYCLONE FORMATION IS NOT EXPECTED DURING THE
NEXT 48 HOURS.

$$
FORECASTER BLAKE/PASCH

[Derek Ortt]

I am not shocked at all this is not mentioned. I also did not mention this tonight and also put it at the end of my PNJ column for the evening

I said about ten times in this thread why this is not worthy of a mention

Did you include this wave in your column this morning?

I write in the evenings. I did not mention on nwhhc though as there is no need

[wxman57]

Don't get too excited yet. Any mid-level spin is fairly weak. Convection is very weak and disorganized. Upper-level winds over the system are out of the east at 35-40 kts, yielding at least 20 kts of shear. You can see the high clouds racing westward atop the disturbance. The actual wave axis is back around 24W. I'd encourage the use of higher-res visible imagery vs. IR to see any lower-level features.

[cycloneye]

30W is where we have to look for something to form,if ever does so.

TROPICAL WEATHER DISCUSSION
NWS TPC/NATIONAL HURRICANE CENTER MIAMI FL
205 PM EDT TUE AUG 04 2009

TROPICAL WEATHER DISCUSSION FOR NORTH AMERICA...CENTRAL
AMERICA...GULF OF MEXICO...CARIBBEAN SEA...NORTHERN SECTIONS OF
SOUTH AMERICA...AND ATLANTIC OCEAN TO THE AFRICAN COAST FROM THE
EQUATOR TO 32N. THE FOLLOWING INFORMATION IS BASED ON SATELLITE
IMAGERY...METEOROLOGICAL ANALYSIS...WEATHER OBSERVATIONS...AND
RADAR.

BASED ON 1200 UTC SURFACE ANALYSIS AND SATELLITE IMAGERY THROUGH
1700 UTC.

...TROPICAL WAVES...

AN ACTIVE SURFACE TROUGH IS ALONG 34W/35W S OF 12N. WHILE IT IS
CURRENTLY NOT ANALYZED AS A TROPICAL WAVE...IT MAY BE
TRANSITIONED TO ONE ON FUTURE SURFACE ANALYSIS. MID-LEVEL
CYCLONIC CIRCULATION IS NEAR THE TROUGH AXIS SUPPORTING
SCATTERED MODERATE/ISOLATED STRONG CONVECTION FROM 7N-10N
BETWEEN 33W-37W. HOWEVER...VISIBLE SATELLITE IMAGERY AND
QUIKSCAT DATA AROUND 0800 UTC INDICATES THAT LOW LEVEL
CYCLONIC CIRCULATION IS FARTHER E AROUND 30W.

http://www.storm2k.org/weather/hw3.php? ... hwvmetric=

[wxman57]

Here's an 18Z meteosat along with the GFS 6hr forecast of surface pressure, analyzed to 1/2 millibar increments. You can see that the GFS has a low about 5 degrees east of the disturbance near 10N/30W. But the few surface obs we have in the area of the GFS low center are all from the west - even north of where the GFS has the low. In addition, pressures there are around 1014mb, sort of high. So I don't think that there is any low center near 30W. Certainly, data don't support a center there.

[wxman57]

To give you the image of what a developing TC looks like on the MIMIC TPW loops, here's a loop of the 3 days leading up to Ike's formation. The circulation is moving off the coast of Africa initially, then becomes very well defined and detached from the wave to the northwest. You can go back to the MIMIC archives and look at such loops for each storm of 2008. They're all similar to the loop below. Currently, this disturbance looks nothing like that. Only the faintest hint of a circulation. But look east on the current MIMIC loop and you do see a circulation associated with the wave axis around 24W-25W and 12N.

Loop of Ike's Formation:
ftp://ftp.ssec.wisc.edu/pub/mimic_tpw/a ... anim72.gif

Fay followed by Gustav. Gustav wave had just moved off Africa:
ftp://ftp.ssec.wisc.edu/pub/mimic_tpw/a ... anim72.gif

Bertha's Formation:
ftp://ftp.ssec.wisc.edu/pub/mimic_tpw/a ... anim72.gif

Dolly starting out in east Caribbean:
ftp://ftp.ssec.wisc.edu/pub/mimic_tpw/a ... anim72.gif

In each of the developments (from tropical waves) last year, there was quite a bit of rotation evident in the image and the system was well-removed from the ITCZ. They develop at the crest of the wave as the rotation detaches. Certainly nothing like that currently in the Atlantic.

[srainhoutx]

All the more reason to look a bit closer to home for any tropical troubles this year.

[Blown Away]

I don't see anything where the GFS initializes and I think the GFS recurves before the islands. I wonder if the blob of convection with cyclonic rotation SW of the GFS initial point develops will it go farther W?

[wxman57]

I don't see anything where the GFS initializes and I think the GFS recurves before the islands. I wonder if the blob of convection with cyclonic rotation SW of the GFS initial point develops will it go farther W?

I think that more likely - it doesn't develop, tracks generally westward, and eventually looks like the current wave approaching the east Caribbean. Just scattered showers/storms. I don't think this is Ana, but can't completely rule out development yet. Maybe next week we'll have a real development threat.

[cycloneye]

HPC Discussion of the tropics in Atlantic

OUTLOOK: MEDIUM RANGE GUIDANCE IS SHOWING A GRADUAL TRANSITION ON
THE NORTHERN PORTIONS OF THE DOMAINS. ON DAYS 04-05...THE RIDGE
OVER THE WESTERN USA WILL RELOCATE TO THE EASTERN USA/WESTERN
ATLANTIC. IN-TANDEM...AN UPPER LEVEL TROUGH WILL THEN ESTABLISH
OVER THE WESTERN ATLANTIC TO NORTH OF THE ISLANDS. DOWNSTREAM FROM
THIS TROUGH...A RIDGE WILL GRADUALLY BUILD/ESTABLISH OVER THE
EASTERN ATLANTIC TO THE NORTH OF 20N. THIS CHANGE WILL COINCIDE
WITH AN INCREASE IN THE MJO...WHICH SHOULD LAST FOR TWO TO THREE
WEEKS. THIS WILL BRING US CLOSER TO THE TYPICAL/MORE SEASONAL
CLIMATOLOGICAL PATTERN OVER THE DOMAIN...AND LIKELY MAKE IT MORE
FAVORABLE FOR TROPICAL CYCLONE FORMATION.

http://www.hpc.ncep.noaa.gov/discussions/fxca20.html

[Ed Mahmoud]

All the more reason to look a bit closer to home for any tropical troubles this year.

Hey, we don't need this wave for action at all. GFS implies Felicia passes near/over Hawai'i? This El Nino season already looks super action packed for the Central Pacific.

We might even get Fujiwara excitement, where Enrique keeps Felicia surpressed further South, increasing the odds of Hawai'i?


And when is the last time we discussed Fujiwara interaction in real time on this board?

[wxman57]

Take a look at the projected oceanic heat content in Felicia's path beyond 60 hrs, Ed:

ftp://ftp.tpc.ncep.noaa.gov/atcf/stext/ ... _ships.txt

After the next 12 hours, heat content begins dropping, down to zero after 72 hours. So it probably won't last to hit Hawaii.

[Ed Mahmoud]

Take a look at the projected oceanic heat content in Felicia's path beyond 60 hrs, Ed:

ftp://ftp.tpc.ncep.noaa.gov/atcf/stext/ ... _ships.txt

After the next 12 hours, heat content begins dropping, down to zero after 72 hours. So it probably won't last to hit Hawaii.

Not super toasty, but we've seen Atlantic cyclones sort of maintain at 25º before.

[Blown Away]

I don't see anything where the GFS initializes and I think the GFS recurves before the islands. I wonder if the blob of convection with cyclonic rotation SW of the GFS initial point develops will it go farther W?

I think that more likely - it doesn't develop, tracks generally westward, and eventually looks like the current wave approaching the east Caribbean. Just scattered showers/storms. I don't think this is Ana, but can't completely rule out development yet. Maybe next week we'll have a real development threat.

I agree. BTW, thanks for posting those cool maps and labeling features, it really helps us amateurs understand what is really happening and I appreciate you taking the time to do that each hurricane season. I know the blob is entrenched in the ITCZ, but until I see the convection and rotation decrease I am not going to rule out a potential Ana from this area.

[cycloneye]

The last time I ckecked,this is not the Felicia thread.

Go here

[Ed Mahmoud]

The last time I ckecked,this is not the Felicia thread.

Go here

Sorry. That will indeed be the action thread.

[srainhoutx]

HPC Discussion of the tropics in Atlantic

OUTLOOK: MEDIUM RANGE GUIDANCE IS SHOWING A GRADUAL TRANSITION ON
THE NORTHERN PORTIONS OF THE DOMAINS. ON DAYS 04-05...THE RIDGE
OVER THE WESTERN USA WILL RELOCATE TO THE EASTERN USA/WESTERN
ATLANTIC. IN-TANDEM...AN UPPER LEVEL TROUGH WILL THEN ESTABLISH
OVER THE WESTERN ATLANTIC TO NORTH OF THE ISLANDS. DOWNSTREAM FROM
THIS TROUGH...A RIDGE WILL GRADUALLY BUILD/ESTABLISH OVER THE
EASTERN ATLANTIC TO THE NORTH OF 20N. [b]THIS CHANGE WILL COINCIDE
WITH AN INCREASE IN THE MJO...WHICH SHOULD LAST FOR TWO TO THREE
WEEKS. THIS WILL BRING US CLOSER TO THE TYPICAL/MORE SEASONAL
CLIMATOLOGICAL PATTERN OVER THE DOMAIN...AND LIKELY MAKE IT MORE
FAVORABLE FOR TROPICAL CYCLONE FORMATION.
http://www.hpc.ncep.noaa.gov/discussions/fxca20.html
[/b]

Hmmm, where have I seen this before...