I wanted to post this..it just came out from Dr. Masters at WU, referencing Dr. Klotzbach and Gray from Colorado State:
A statement from Dr. Masters this morning —
“Chantal’s formation on July 8 is an usually early date for formation of the season’s third storm, which usually occurs on August 13. A large number of early-season named storms is not necessarily a harbinger of an active season, unless one or more of these storms form in the deep tropics, south of 23.5°N. According to Phil Klotzbach and Bill Gray, leaders of Colorado State’s seasonal hurricane forecasting team,
“Most years do not have named storm formations in June and July in the tropical Atlantic (south of 23.5°N); however, if tropical formations do occur, it indicates that a very active hurricane season is likely. For example, the seven years with the most named storm days in the deep tropics in June and July (since 1949) are 1966, 1969, 1995, 1996, 1998, 2005, and 2008. All seven of these seasons were very active. When storms form in the deep tropics in the early part of the hurricane season, it indicates that conditions are already very favorable for TC development. In general, the start of the hurricane season is restricted by thermodynamics (warm SSTs, unstable lapse rates), and therefore deep tropical activity early in the hurricane season implies that the thermodynamics are already quite favorable for tropical cyclone (TC) development.”
Two of this season’s three storms have formed in the deep tropics–Tropical Storm Barry, which formed in the Gulf of Mexico’s Bay of Campeche at a latitude of 19.6°N, and now Tropical Storm Chantal, which formed at a latitude of 9.8°N. With recent runs of the GFS model predicting formation of yet another tropical storm southwest of the Cape Verde Islands early next week, it appears that the Atlantic is primed for an active hurricane season in 2013.”
Good day everyone!
This forecast is based on information from the 11:00 a.m. EDT Advisory, and the last updates received from model data.
At 11:00 p.m. EDT yesterday evening, INVEST 95L was upgraded to Tropical Storm Chantal. As of the 11:00 a.m. EDT Advisory from the NHC, the following information was available on Chantal:
11:00 AM AST Mon Jul 8
Location: 10.9°N 51.7°W
Moving: WNW at 25 mph
Min pressure: 1005 mb / 29.68 in
Max sustained: 45 mph
As stated in the NHC Forecast Discussion, the motion of Chantal is to the WNW at 25 mph. I expect this motion to continue for the next 12-18 hours, before a more prominent turn to the WNW takes place (285-290). Analysis of current and forecast steering layers maps indicates this motion. However, after careful analysis and consideration of current satellite loop imagery of various channels, combined with the steering forecast analysis, I do concur with the current NHC forecast track, however I am initially to the left for the next 12-24 hours, and just left of the TVCC / TVCN model consensus. I do however agree with the overall track based on forecast steering, as a weakness in the subtropical ridge occurs within the next 48-60 hours off the SEUS coast. This should draw Chantal, or what’s left of Chantal, on a more NW course in that time, and eventually bend back toward the U.S. coast. Right now, not expecting anything strong, should she regenerate. Again, this is based on current forecast parameters information of this morning.
Maximum sustained winds are 45 mph. The NHC does indicate some further slow strengthening of Chantal, however based on the current wind shear map from CIMSS, and Zonal Shear forecast from the GFS 06Z run, Chantal may not see any change in strength until about sometime later this afternoon, as upper level winds become a little more conducive for development. The problem then lies after she enters the Caribbean, where she begins to lose upper air support in about 48 hours. As you can see by the current shear map, she is beginning to move into an area where shear increases.
Another factor that has come into play as I’ve been analyzing and typing…DRY AIR. Analysis of VIS and RGB loop imagery indicates some slight ingestion of dry air, based on some small outflow boundaries noted in the imagery. This indicates she may be jut starting to have to battle dry air, or it could be just a “hiccup” for the time being. Based on these factors, I believe the NHC may come down slightly on their intensity forecast, and if not, I do not foresee an increase in the forecast.
I will continue to monitor Chantal throughout the day, and will have another update sometime this evening.
I will be open to questions after 1:00 p.m. today
Have a blessed day!
T. F. “STORM” WALSH III
GMCS, USCG (ret)
METEOROLOGIST / HURRICANE SPECIALIST
MEMBER WEST CENTRAL FL AMS
CERTIFIED SKYWARN OFFICIAL STORM SPOTTER (advanced)