LarryWx wrote:The 18Z NAM clobbers practically the entire GA/SC/far NE FL immediate coast with 0.75" of qpf, the biggest hit of any model run yet except the 6Z ICON (German model) clobber! So, 0.75" of qpf that is practically all wintry except maybe not practically all wintry NE FL (but still probably majority wintry). The 0.50" line now goes inland 50+ miles much of SE. A bullseye of 1.5" is 20 miles offshore Hilton Head. Often the NAM is wet biased (and ICON may be too). So, I'm quite wary about that. However, even if the qpf is cut in half, this is still a major hit. Also, the trend has been wetter. So, these amounts may not be as inflated as usual, if at all.
The key to me as to whether or not this would likely be a major SE coastal hit is the direction of movement of the surface low from Grand Bahama Island. If it moves NE from there like most models, including the 18Z GFS, have been showing, it likely not be an historic hit though it could still have major impact in some areas. However, if it were to move NNE from Grand Bahama like recent NAM and ICON runs have been showing, the chances of this ending up historic would go up significantly.
Yes Larry I saw the changes earlier after the 6Z runs. The earlier GFS runs maintained up until today that the intensifying Low Pressure system would move farther off shore and not impact the Eastern U.S. seaboard.
However, the upper shortwave disturbance on this afternoon's NAM run looks rather strong and the disturbance is also showing a better moisture field by Wednesday. Also. the shortwave. is hanging back a bit over the Northeast GOM/Big Bend region by 18Z Wednesday afternoon. The broad upper trough axis is really deepening at this juncture. This afternoon's NAM and to some extent, the 18Z GFS, are hinting at the upper trough axis possibly being slightly more negatlively tilted. That orientation most definitely would help pull the intensifying storm closer to the Southeast U.S coast on Wednesday and Wednesday evening, before pulling northeast away from the region by Thursday morning.
So, this situation is getting more intriguing by the hour. The prospects imo of seeing potential wintry precip across extreme inland Northeast Florida northeast up into Southeast Georgia are beginning to increase. The prospects also farther north along the coast from the Carolinas to New England also are increasing with this storm. It will all come down to the usual placement/track of the Low Pressure and how far inland the precipitation will get into that very cold air. which will already be well entrenched across the Deep South middle of this week.
More later....