Potential Cape Verde Storm

[Randall Marable]

Since the NHC has highlighted this wave off of the coast of Africa I thought I would go ahead and initiate a new thread on this potential threat. If you believe some of the computer models this area should eventually become Tropical Depression Number 3 and something potentially much more serious down the road.



TROPICAL WEATHER OUTLOOK
NWS TPC/NATIONAL HURRICANE CENTER MIAMI FL
200 AM EDT WED AUG 12 2009


3. A LARGE AREA OF SHOWERS AND THUNDERSTORMS NEAR THE COAST OF WESTERN
AFRICA IS ASSOCIATED WITH A VIGOROUS TROPICAL WAVE. SOME SLOW
DEVELOPMENT OF THIS SYSTEM IS POSSIBLE OVER THE NEXT FEW DAYS AS
IT MOVES TO THE WEST AT 10 TO 15 MPH. THERE IS A LOW CHANCE... LESS
THAN 30 PERCENT...OF THIS SYSTEM BECOMING A TROPICAL CYCLONE DURING
THE NEXT 48 HOURS.

 

[Randall Marable]

San Juan is beginning to include discussion of this wave as well within their AFD's. I guess it is safe for us to assume that since so many models are indicating some type of development of this wave, everyone concerned is keeping a very close eye on this one.



AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE SAN JUAN PR
231 AM AST WED AUG 12 2009


ANOTHER LARGE TROPICAL WAVE IS TRACKING BEHIND TROPICAL DEP 2 AND WE
SHOULD MONITOR ITS PROGRESS SINCE GFS IS INDICATING POSSIBLE
DEVELOPMENT...AND THE CHANCE THAT IT MAY HAVE SOME IMPACT ACROSS THE
NORTHEAST CARIBBEAN NEXT TUESDAY AND WEDNESDAY. KEPT MAX SURFACE
WINDS AT 25 KNOTS FOR GRIDS FOR DAY 7 AND 8 PERIOD. A REMINDER...IT
IS AUGUST AND CLIMATOLOGICALLY A TIME WHEN THE TROPICS BECOME MORE
ACTIVE. ALL LOCAL RESIDENTS...MARINERS AND VISITORS ARE REMINDED TO
MONITOR THE WEATHER CLOSELY...AS WE APPROACH THE MORE ACTIVE PART OF
THE HURRICANE SEASON.

 

[Jason Foster]

Two previous threads for additional reference and discussion:

http://www.stormtrack.org/forum/showthread.php?t=21538

and

http://www.stormtrack.org/forum/showthread.php?t=21513

 

[Randall Marable]

Invest 90L

Computer models continue to insist this invest will be a potential threat to either the Lesser Antilles and/or the Bahamas within 7 to 8 days or so. Still way to early to say whether or not 90L will be a threat to the US. The GFS has been waffling back and forth from a threat to the US to a potential near-miss the last few days. The latest 08/13 12Z run of the GFS continues to insist this area will pose a threat to the north-most Windward Islands. As with all systems like this, the overall steering currents around days 10 to 13 will ultimately determine where this system will end up going.

 

[Randall Marable]

Computer models continue to insist this invest will be a potential threat to either the Lesser Antilles and/or the Bahamas within 7 to 8 days or so. Still way to early to say whether or not 90L will be a threat to the US. The GFS has been waffling back and forth from a threat to the US to a potential near-miss the last few days. The latest 08/14 12Z run of the GFS continues to insist this area will pose a threat to the north-most Windward Islands. As with all systems like this, the overall steering currents around days 10 to 13 will ultimately determine where this system will end up going.

I might need to revise that time frame. I guess it all depends on which model you want to believe. For example, the GFS is slightly faster with the forward speed with 90L than the ECMWF. This may explain why the ECMWF believes the system will not reach the East Coast, giving that 'forecasted' trough time to reach the East Coast first before the system arrives. Again I we all understand a lot can and will change between now and then, but it's still kinda of interesting to follow the day-to-day changes within and among each model run nevertheless.

 

[Randall Marable]

Right or wrong, no one can accuse the GFS of not being constistent on taking this system into northern most Lesser Antilles into the Southern Bahamas in the long term. In addition, there is a fairly tight consensus among the major forecasting models of taking this system into these regions as well. This tells me that a strike on or around the Puerto Rico area is becoming more and more likely. Of course nothing is set in stone so there are always other possibilities with this system. However, if this system begins to develop like many of the models are forecasting, then everyone in and around these regions should seriously began to complete their respective storm preparations here in the near future.

 

[Randall Marable]

For those of you who speak spanish, this Puerto Rico local TV station's weather forecaster spent most of her time discussing 90L. It appears there is an increasing local/regional concern over the future prospects of this system.

http://www.wapa.tv/tiempo.php

 

[Randall Marable]

Forthcoming Tropical Depression # 3

Baring some drastic changes in the short-term, from the presentation of the latest satillites loops, quikscat images, and latest verbage from the NHC it looks as if this system should be upgraded within the next 12 hours or so. The latest computer model runs have shifted the track slightly to the north as compared to yesterday. It remains to be seen if this shift to the north is only temporary and are these models are taking in consideration of newly formed Tropical Storm Ana. I think the best bet at this point is to wait another 24 hours or so to allow the models to catch up with what's actually going on. As is always the case with these developing tropical systems, there is usually a lag in model accuracy due to slightly outdated data, especially in cases where a tropical system undergoes rapid intensification.