Masters student in tropical meteorology at FSU. Raised in Alaskan blizzards, but drawn toward tropical cyclones by their superior PGF.
By: Levi32 , 4:44 PM GMT on August 12, 2011
Please note that these tidbits do NOT reflect the official forecasts of the National Hurricane Center, and should not be taken as such. While tropical cyclones exist in the Atlantic, the official NHC forecasts will be posted in the lower part of this blog. Please refer to those when making decisions, and heed the advisories and evacuation statements of your local National Weather Service Office.
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We have quite the train of invests out in the Atlantic today. We now have four active invests, 92L-95L. Invest 95L is along a frontal boundary just NW of Bermuda, likely baroclinically influenced, and although it has a circulation developing, probably won't deserve classification, but that will be up to the NHC. It is no threat to land.
94L is the piece that split off from Emily, and is now northeast of the Antilles, trying to come down around the Bermuda High and cause mischief a second time. Coming down around the SE flank of an upper ridge is very difficult to do, and most systems attempting that don't survive, so I still have doubts that 94L will develop significantly, but it is worth keeping a wary eye on in case it tries to pull off another performance. The ghost of Emily is very persistent, after all.
Invest 92L is southeast of 94L, and is a lot farther north than it was yesterday, now near 18N as the northern portion of the wave split off from it due to dry air and elongation. Dry air is still plaguing this system, though it is starting to move into warmer waters today. This may still have a chance at developing, but even if it does, it shouldn't get too strong. A ridge building in to its northeast should keep it moving WNW to NW for a little while, eventually recurving near the Bermuda Area, so those folks should keep an eye on this feature in case it develops.
Invest 93L is southeast of 92L, and has lost most of its convection from yesterday. As I mentioned, we shouldn't really get too excited about it immediately developing, as some models had it doing. It still lacks circulation, and it is still embedded in the monsoon trough, which does protect it from dry air, but also impedes the focusing of surface convergence (piling up of air) near the system. The fact that 93L is remaining weak is almost not good news, as it means that it could sneak farther west before gaining latitude. Thus, the Caribbean islands may need to watch 93L in case it tries to develop near their area and come into the northeast Caribbean.
The 0z ECMWF and 6z GFS actually take 93L through the entire Caribbean and into the Yucatan Peninsula in 10 days. I find these solutions to be a bit premature and perhaps too far south, but we will see how future runs treat the system. The steering features in the forecast remain the same. A sharp trough off the eastern seaboard during the next 4 days should recurve 92L, but will lift out quickly as most troughs have done in the western Atlantic so far this season. Once it lifts out, ridging develops over southeastern Canada, but the weakness between the Texas ridge and Atlantic ridge still remains over the eastern seaboard. This results in yet another fragile pattern that is capable of recurving some storms, like 92L, but can also bring storms to the coast if they come in far enough south, as 93L might. This persistent weakness over the east is why I think the model runs bringing 93L into the Yucatan may be a bit too far south, but if 93L remains as weak as it is now for the next 6-7 days, such runs illustrate the potential danger for it to get right into all of those land areas in the Caribbean region. The pattern supports mischief close to land, and thus we should keep a close eye on 93L in case it develops. The eastern Caribbean islands will have to watch this system first, though it is not much of a worry right now unless it starts to wind up before getting there. It may never develop either, but with the MJO coming back to our basin as it chugs westward, and with the time of year that we are in, chances are it will try to wind up down the road and threaten somebody.
We shall see what happens!
Invest 92L Visible/IR2 Floater:
Invest 92L Track Forecast Models:
Invest 93L Track Forecast Models:
Caribbean/East Pacific Visible/IR2 Satellite (click image for loop):
Central Atlantic Visible/IR2 Satellite (click image for loop):
Atlantic Tropical Surface Analysis:
200mb Vertical Velocity (green areas represent upward motion associated with the MJO):
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