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Tropical Storm Colin Discussion, Tuesday August 3, 2010 at 620 am EDT/520 am CDT

 

Tropical Storm Colin:
Here is the 5 am EDT/4 am CDT Information On Tropical Storm Colin:
Location: 14.0 North Latitude, 47.2 West Longitude.
Maximum Sustained Winds: 40 mph.
Movement: West-Northwest or 285 Degrees at a forward speed of 23 mph.
Minimum Central Pressure: 1006 millibars or 29.71 inches.

TD #4 has become better organized overnight and satellite imagery is showing curved bands of convection wrapping about halfway around the storm on its western side. Intensity estimates based on satellite imagery indicates that this system now has 40 mph winds; so it has been upgraded to Tropical Storm Colin by the National Hurricane Center. Some strengthening is likely today through Wednesday as wind shear values will generally range from 7 to 14 knots. After Wednesday, westerly wind shear is forecast to increase over the storm thanks to an upper level low pressure system over the southwest Atlantic. One caveat to this intensity forecast is that if Colin tracks further south than what the guidance package is forecast (which is quite possible), not as much shear will impact the storm and greater strengthening would be possible. For now, I’m following the NHC intensity forecast and cap the storm off at 60 mph by Wednesday.

Colin is currently tracking west-northwest at a forward speed of 23 mph. Colin is currently being steered by a ridge of high pressure to its north and an easterly tropical jet. Colin is forecast to continue tracking slightly north of due west at a forward speed of 20+ mph today into tonight. By Wednesday, the storm should slow down some in forward speed as it starts to feel a weakness in the high pressure ridge. The track model guidance is in pretty good agreement with the forecast track from today through Wednesday, however, after Wednesday, the track guidance continues to diverge on a forecast track. The GFS model and the European model has shifted westward overnight in its forecast track with the Euro model forecasting a track across the extreme northern Leeward Islands by late Wednesday and then a track to the east of the Bahamas on Friday into Saturday with a close brush with the outer banks of North Carolina on Monday. The GFDL and HWRF models continue to forecast a track well out into the Atlantic and imply a possible threat to Bermuda in about five days. The Canadian model is even further west and forecasts a track that would impact much of the Leeward Islands Wednesday night into Thursday morning, Puerto Rico during the day Thursday, much of the Bahamas from Friday through Saturday and ultimately a track that keeps it just barely offshore of the coast of eastern Florida, Georgia, South Carolina and North Carolina during Sunday and Monday.

Personally, I continue to think that the many of the model guidance members are still overdoing the strength of the low pressure trough and eroding the ridge of high pressure too much. I’m leaning towards a track somewhere between the European and Canadian model and this is significantly west of the National Hurricane Center forecast. Could I be wrong?? Absolutely!!; but this is what my analysis is showing and I’m sticking to my guns that this will track further west like what the Canadian and European models are implying. So, this may actually track right over the northern Leeward Islands Wednesday night as a tropical storm and just north of the Virgin Islands and Puerto Rico during Thursday morning as a tropical storm. After that, I suspect that this may take a track very close to or just a shade east of the Bahamas Friday through Saturday as a Category 1 hurricane and then potentially come fairly close, but not make landfall on the US Southeast Atlantic coast Sunday and Monday as a hurricane.

All interests in the Leeward Islands, Virgin Islands and Puerto Rico should continue to closely monitor the progress of this storm. I will continue to monitor things closely and keep you all updated.

Elsewhere In The Tropical Atlantic:
There are some other areas in the Atlantic that are worth mentioning this morning. The first is a tropical wave located in the eastern Caribbean. Satellite imagery showed widespread shower and thunderstorm activity associated with this wave and some strengthening seems likely, especially once it gets west of 74 West Longitude later Wednesday. Pretty much all of the model guidance forecasts development into a tropical depression or tropical storm but keeps it tracking west right into Honduras, Belize and the Yucatan Peninsula late this week. I generally agree with this and do not think that it will gain much, if any northward progress into the Gulf of Mexico as I think the high pressure ridge will keep it on a general westward track.

I’m also keeping an eye on a couple of other tropical waves. One that is right behind Colin and another that is now just coming off of the coast of Africa. The tropical wave right behind Colin is fairly disorganized and the one coming off of the coast of Africa may find some favorable conditions in a couple of days once it tracks southwestward away from the coast of Africa. So, both of these systems will be watched closely over the coming days.

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