FROM CROWN WEATHER THIS MORNING:
Issued: Saturday, July 31, 2010 735 am EDT/635 am CDT
For the Tropical Weather Discussion with Maps, Images and Graphics, Go To:
http://www.crownweather.com/?page_id=325.
Discussion
The Eastern Atlantic:
First area to discuss is a pretty large area of showers and thunderstorms over the eastern Atlantic. This large system is a combination of a tropical wave located near the Cape Verde Islands and a trough of low pressure (which is/was Invest 90L) located about 750 miles southwest of the Cape Verde Islands. It looks like to me that the tropical wave near the Cape Verde Islands will likely become the more dominant system as environmental conditions are more favorable in this area and there is more moisture to work with. Looking at the forecast environmental conditions over the next few days,
it appears that conditions should remain favorable for development in this area over the next few days. With that said, development will be quite slow to occur. The reason why is that if we get a low pressure system forming in this area, it will need to break off and sustain itself away from the Inter-Tropical Convergence Zone. In addition, the disturbance near the Cape Verde Islands may actually combine with whatever is left of Invest 90L. It seems very likely that either of these systems (Invest 90L or the Cape Verde system) will be classified as a tropical depression this weekend into early next week and I think the earliest that this may happen is perhaps Tuesday or Wednesday. The model guidance has been very inconsistent on whether this develops or not. The latest NOGAPS model forecast is very aggressive and forecasts a hurricane moving through the Leeward Islands headed for Puerto Rico next Saturday. The other model guidance really does not forecast development from this system. In fact, there is no in between in the model guidance, they're either forecasting a tropical wave that never develops or a full-fledged hurricane. What this may mean is that environmental conditions will be favorable for development, but it is unsure whether this system consolidates into one main system. I strongly suspect that you will see the model guidance continue to be inconsistent on development over at least the next few days.
So, let's throw out the exact model details and look at the upper level conditions and patterns: As I have already mentioned,
I don't think you will see classification of a tropical depression from this system until Tuesday or Wednesday. After that, if this develops, I think the chances are pretty high that it would strengthen and track westward. I really do not think that this system will recurve out into the open Atlantic; therefore this could be a threat to land down the road. The reason why I don't think this system will curve out into the open Atlantic is that with the Madden Julian Oscillation returning to a more favorable phase very shortly; this would favor a ridge of high pressure to be dominant over the eastern United States. It should be noted that while the model guidance do not agree on the specifics of this system (whether it develops or not), they do agree that a ridge of high pressure will be dominant to the north of this system for at least the next week. This leads me to strongly believe that the northeastern Caribbean Islands need to monitor this system very closely since this will be on your doorstep in about 5 to 7 days. After that, the pattern would favor a west-northwest course during the week of August 8th and potentially track either through the Bahamas and potentially towards the United States. Bottom line is that this system should be watched over the next several days to see if it develops or not. Right now, I give this entire system a very low chance of developing into a tropical depression through Monday and a moderate chance of developing sometime between Tuesday and Thursday with this system in whatever form it is in potentially affecting the northeastern Caribbean between Thursday and next Saturday. Any threat to the US coastline is at least 10 to 12 days away, so for now we will keep a very close eye on it for a possible long range threat.
I just noticed that the 0600 UTC GFS model is back on board with developing this system into a tropical cyclone around Wednesday; however, it is faster with the overall track and affects the Lesser Antilles on Wednesday night or Thursday morning and then Puerto Rico on Thursday night. After that, the GFS model forecasts a possible impact from eastern Florida on August 11th to South and North Carolina from August 13th to August 15th. Again, I want to strongly emphasize that you should not look at the details of the model, in terms of storm tracks, just that the model is seeing a favorable environment for development.
In conclusion, I will be monitoring this system closely over the next several days and will keep you all updated.
Caribbean Disturbance:
The area of disturbed weather in the Caribbean that is associated with a tropical wave has lost a lot of its thunderstorm activity overnight. I do not expect development this weekend from this system; however, it may need to be watched early next week when it reaches the southwestern Caribbean where conditions are more favorable. With that said, this tropical wave is tracking pretty far south in Latitude and it should primarily be a threat to Central America as the easterly wind flow will likely push this system into Central America in a few days. Interests in Honduras, Nicaragua, Guatemala and Belize should keep a close eye on this system over the next few days. I give this system a very low chance of development this weekend and a low to moderate chance of development early next week before it tracks inland over Central America.
Elsewhere in the Tropical Atlantic:
Even though things may get kind of active in terms of development over the next week or so, this is not the main show!! The Madden Julian Oscillation is currently in an unfavorable phase for development, however, it is expected to become very favorable somewhere between August 10th and August 14th and this is when things may get very active. I still think the period between mid-August and mid-October will be very active with the potential for at least 12 to 13 named storms during this two month period. More important than that, the overall impact to land will be above normal this season and I have no change in my thinking regarding which areas are at most risk this season (eastern North Carolina, south Florida and the northwestern Bahamas, the entire northern and western Gulf coast, from Texas to the Florida Panhandle, the Lesser Antilles, the Virgin Islands and the entire northwestern Caribbean, including the Yucatan Peninsula, western Cuba and the Cayman Islands). In addition to this, I still think that this will be a hurricane season that could run right into November and possibly early December.
As I have mentioned a couple of times before and I will mention it again: Please go over your hurricane preparedness kit and if you need supplies and can afford it, go to your local supermarket, your local Target, Wal-Mart or Lowe's and purchase what you need.
Since I do not expect development this weekend, a tropical weather discussion will not be issued on Sunday. The next tropical weather discussion will be issued by 7 am EDT/6 am CDT Monday morning.
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, pretty imformative from CrownWeather! Something to keep an eye on...during the next couple of days for sure.
