From Jonathan Vigh:
Tropical Depression Gaston continued to rain itself out today over North Carolina and southern Virginia. Over the last 24 hours, 2-5" of rain has fallen over central North Carolina and southeastern Virginia. Wind gusts up to 45 mph were reported near the NC/SC border. Gaston will continue its plodding trek through Eastern Virginia and the Del Marva peninsula and gradually lose its identity as it tangles with an approaching cold front. An alternate scenario is that Gaston moves out over open (but cold) waters and attempts a come-back, perhaps as an extratropical entity. Tropical Storm Hermine lost its head and is running towards Massachusetts. Vertical wind shear at midlevels separated Hermine's low level center from the deep convection this morning. The system is still at tropical storm strength, however, and may brush southeast Massachusetts overnight. Therefore, the National Hurricane Center has issued a tropical storm warning for this area. At 21Z, Hermine was at 38.4N 71.3W, or 210 miles south-southwest of Nantucket, Massachusetts, moving north at 18 kt. Winds are at 45 kt and the estimated central pressure is 1008 mb. With Gaston and Hermine soon to be gone, all eyes turn towards Hurricane Frances. The storm fought through mild southerly wind shear yesterday, but now appears to be under little if any vertical wind shear. Frances has a healthy appearance in the satellite imagery this afternoon: the outflow is good in all directions and expanding in time, a sign that the environment is favorable for intensification. Indeed, at 18Z, recon aircraft found that the pressure had fallen to 948 mb (down from as high as 958 mb overnight). The aircraft also found a an 18 nm inner eye with an outer eyewall 48 nm in diameter. Frances appears to be nearing the end of another eyewall cycle today, and the storm will probably strengthen as the outer eyewall contracts. At this point, there do not appear to be any factors that would cause substantial weakening of Frances, so the official forecast calls for a dangerous 120 kt storm in five days. Frances will pass north of the Lesser Antilles overnight. Sustained tropical storm force winds are likely in this area, and there is a possibility that the northernmost islands (Anguilla, Virgin Gorda) could experience hurricane conditions. Tropical storm warnings are in effect for the northern U.S. and British Virgin Islands, Culebra, Vieques, and Puerto Rico. If the storm stays on track, tropical storm force winds should remain close to or offshore of northeast Puerto Rico. The Bahamas will likely be the first to feel Frances' full fury. A strong ridge is forecast to continue to steer Frances on a west-northwest course towards the southeast U.S. Coast, possibly making a landfall as early as Saturday morning. At this point in time, there does not appear to be any trough that could recurve the storm before landfall. If the ridge weakens towards the end of the week, Frances could travel further north and hit North Florida, Georgia, or even South Carolina by Sunday or Monday. Alternatively, if the ridge strengthens, Frances could make a quick left turn into South or Central Florida by Saturday morning. Since any potential landfall is at least 5 days away, there is still much uncertainty -- the storm could even miss the U.S. entirely, although the chance of that happening seems to be decreasing with time. Residents in these areas should closely monitor Frances progress this week and remember that 4 and 5 days forecasts typically have track errors of a couple hundred miles. At 21Z, Frances was at 19.5N 60.0W, with maximum sustained winds of 110 kt. She has also increased her forward motion, moving westward at 13 kt.
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