January 2, 2002
Good evening friends. As noted in the discussion earlier in the day, there was still some uncertainty among guidance as to the final impact of the storm system currently developing in the Gulf of Mexico. It has become clear to me tonight, that guidance is once again blurring the picture as to the final track of the said storm system. In short, there were several pieces of data missing from tonight's model suite, the most important of which, in my opinion, is the underestimation of a jet max in the rear right quad of the trough which was 20-30+kts higher than what guidance estimated. Among the implications of this, as seen on satellite and water vapor imagery, is that the low in the Gulf is already farther North than progged. Although missing data by 20-30kts may not seem like a big deal, the area which was misinterpreted is crucial in determining how amplified the trough gets, how long and when the upper low closes off, and of course, the exact track of the system.
Before I get into discussion of the storm, let me first clarify exactly where I have stood with this system in terms of precipitation. While guidance still paints a bullseye in parts of NC and VA with lighter snows barely making it into Southern NJ, I still feel that the track of the low will be slightly farther North than what we have seen the past few guidance runs, allowing some light snow and/or flurries to reach as far North and West as the PHL area. In short, even though the GGEM model has been getting alot of criticism recently, I feel that it's interpretation of the QPF fields on the 0Z Jan 2 run, do not look that unreasonable. Until I see concrete evidence leading in the other direction, I see no reason to back off of my thinking. At this time, I do not feel that our area gets in on the moderate-heavy snow, but it is still not entirely out of the realm of possibility. I've seen stranger things happen with storms 36-48 hours out.
A few trends that keep standing out from run to run are the increased strength of the upper low as it closes off, the longer duration of it staying closed, the slowing down of the upper air features, and at the surface, the trend to move the system farther Northward before taking on an East-Northeast component away from the coast. Whereas 36 hours ago, guidance took the system Northward to about Southern NC, tonight, signs are that the shift may not happen until it nears the VA/NC border at the earliest (the low should still be away from the coast, but just using those points as latitudinal references). That is a shift of about 100-150 miles Northward over the past several runs. Do I think the low will hug the coast all the way into Maine? No, not at all, but it still bears watching for us in the Middle Atlantic. If the trend farther North continues, which I would not be surprised, folks in Southern NJ, parts of DE, and even MD would be under the gun for accumulating snows. Heck, the system is still 36 hours or so away, so plenty of changes could happen (surprises?).
That is really all for now as I am still suffering the effects of the flu and need sleep badly. In short, an area of low pressure will be emerging from the Gulf of Mexico late tomorrow night or early Thursday as it crosses over Florida and into the Gulf Stream waters off the SE Coast. There are good indications the dynamically, the system will develop rather quicky, although I am not quite certain it reaches 'bombogenesis' criterea at this time. Snow will spread into parts of NC and VA during the day on Thursday as the low moves to a position just East of Cape Hatteras by late Thursday night or early Friday. As always, this is where things get tricky. If the upper low is able to interact with the surface low, a track closer to the coast is likely. In any event, I expect the system to get as far North as the very Southern tip of the DelMarVa peninsula before turning ENE. Again, it will not take many minor changes for this storm to shift or to continue Northward just a bit farther before making it's turn. Even though I am starting to lean slightly against the upper low capturing the surface low and pulling it Westward. I must caution you that it will not take much interaction between that upper low and the surface low for this scenario to take place. Right now, still sticking with the chance for light snow in our area late Thursday night into Friday. That's all for now. Take care!
S.B.
