Jeff co-founded the Weather Underground in 1995 while working on his Ph.D. He flew with the NOAA Hurricane Hunters from 1986-1990.
By: Dr. Jeff Masters , 8:46 PM GMT on August 23, 2014
(By Steve Gregory - Substituting for Dr. Masters who is on Vacation.)
Over the past few hours, a low level circulation appears to be developing in the vicinity of 21°N/73°W (near Great Inagua Island) based on both RECON reports and high resolution VIS imagery loops.
While there is some convection developing close to this circulation feature, and there have been A/C sampled wind reports of gale force– it’s probably a ‘toss-up’ whether NHC will officially ‘call’ this Tropical Storm Cristobal within the next couple of hours – or wait for additional convection and confirmation that this is in fact, the development of a definitive circulation center. Regardless of classification, the central circulation is moving Northwestward at about 15Kts, and will be moving into the central Bahamas on Sunday with tropical storm conditions.
There continues to be significant variations among all the models on the future evolution of this cyclone, but the general consensus is that the storms’ forward motion will slow during the next 24-48 hours as steering currents weaken in response to the weak TROF off the east coast that extends southward towards the NW Bahamas. At the same time, a slow but steady increase in intensity appears likely, with the storm reaching the NW Bahamas by late Monday.
The threat of CAT 1 hurricane conditions anywhere from southern Florida to the Mid-Atlantic coast continues – though this is certainly not a forgone conclusion as several reliable models continue to forecast the storm to turn northward and then northeastward by Monday and Tues, remaining well offshore without making landfall - paralleling the east coast from Florida to North Carolina.
Elsewhere in the Tropical Atlantic...
A broad, large scale easterly wave located in the central Atlantic is moving westward with little shower activity, while a strong disturbance has moved off the African coast and is also moving westward at ~20Kts. This second disturbance bears monitoring – but at this time, is unlikely to develop for at least the next 5 or more days.
Fig 1: VIS imagery loops show a general low level circulation center near 21N°/73°W and has been confirmed by RECON over the past 2 hours. The system is now moving Northwestward at 18Kts.
I’ll have a complete update late Sunday morning.
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