Fiona has been down graded to a Depression as mid/upper level Westerly shear blows the tops of any convection near the center of circulation.
90L looks to become a Tropical Depression at anytime during the next 24 hours.
And closer to the Lesser Antilles, 99L gained some convection near the surface circulation as it heads generally W to WNW and potentially more favorable conditions for tropical development later this week near Hispaniola and the SE Bahamas.
The models continue to struggle with the eventual track of this tropical disturbance beyond the Bahamas. The latest 06Z GFS suggests a stronger SE Ridge and brings this tropical disturbance over the Florida Keys into the SE Gulf early next week. I caution everyone that until we actually see Tropical Cyclone Genesis, the computer models will struggle and swing wildly from run to run. That said the potential does exist for there to be a blocking SE Ridge in place which tends to favor a more Westerly track of this tropical disturbance, but as always the computer models typically cannot be trusted beyond 3 to 5 days out. We will continue to monitor the Tropics because we are marching to Peak Season that occurs around September 12th or so.
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90L has been upgraded to Tropical Depression # 7 in the far Eastern Atlantic...
TROPICAL DEPRESSION SEVEN DISCUSSION NUMBER 1
NWS NATIONAL HURRICANE CENTER MIAMI FL AL072016
500 PM AST MON AUG 22 2016
The low pressure area located west-southwest of the Cabo Verde
Islands has developed a well-defined circulation and sufficient
organized convection to be considered a tropical depression.
Microwave imagery suggests that the system is likely still
consolidating, with two or more vorticity centers rotating around
a mean center. The initial intensity is set to 30 kt in agreement
with a satellite intensity estimate from TAFB.
The initial motion is 275/16. The cyclone is on the south side of
a deep-layer ridge over the eastern Atlantic, and as a result it
should move generally west-northwestward for the next 36-48 hours.
Beyond that time, the cyclone is forecast to turn northwestward
toward a weakness in the ridge over the central Atlantic. The
track guidance is in good agreement with this scenario, and the
forecast track lies near the consensus models.
The depression is currently in an environment of light to moderate
easterly vertical shear. This, combined with warm sea surface
temperatures, should allow strengthening. One possible negative
factor, however, is a tongue of African dust/dry air wrapping
around the west side of the circulation. On that basis that the
dry air will not stop development, the intensity forecast calls for
steady strengthening through 72 hours. After that time, arrested
development is likely due to the cyclone encountering moderate to
strong westerly vertical shear.
Crazy to see models go in the completely opposite direction. The ECMWF solution in general is rather interesting with high pressure setup over the northeast United States. Obviously this is a week to a week and a half out but that would not fair well for the gulf in general. Key factors here will be development (if any), how fast ridging breaks down/moves west, and any influence of a ULL in breaking down the ridge and increasing shear for 99L. Still have a lot of model disparity and run to run bias.
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A lot of strong ridging in the extended range along the E coast. Heights of 591 to 594dm over the SE US this weekend. Ensemble tracks are more important at this juncture than the operational runs. Hard to find a way for this to escape north with the forecasted steering pattern in place on many of the models. Something to watch.
jeff wrote:A lot of strong ridging in the extended range along the E coast. Heights of 591 to 594dm over the SE US this weekend. Ensemble tracks are more important at this juncture than the operational runs. Hard to find a way for this to escape north with the forecasted steering pattern in place on many of the models. Something to watch.
Yea the only thing that I saw that could help it escape north would be a mix of the ULL paired with the TD Seven breaking down the ridge just enough to cause a weakness. Even then I think that would be rather unlikely. Unfortunately the Bahamas is forecasted to have pretty good conditions in about 5 days.
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jeff wrote:A lot of strong ridging in the extended range along the E coast. Heights of 591 to 594dm over the SE US this weekend. Ensemble tracks are more important at this juncture than the operational runs. Hard to find a way for this to escape north with the forecasted steering pattern in place on many of the models. Something to watch.
Jeff should the Houston/Galveston area be paying attention to 99L.
jeff wrote:A lot of strong ridging in the extended range along the E coast. Heights of 591 to 594dm over the SE US this weekend. Ensemble tracks are more important at this juncture than the operational runs. Hard to find a way for this to escape north with the forecasted steering pattern in place on many of the models. Something to watch.
Jeff should the Houston/Galveston area be paying attention to 99L.
jeff wrote:A lot of strong ridging in the extended range along the E coast. Heights of 591 to 594dm over the SE US this weekend. Ensemble tracks are more important at this juncture than the operational runs. Hard to find a way for this to escape north with the forecasted steering pattern in place on many of the models. Something to watch.
Jeff should the Houston/Galveston area be paying attention to 99L.
It is always good to keep an eye on things...most of us would have never thought Ike would get here from where it was when it formed. I don't like the fact that there is fair agreement on a good amount of ridging over the SE US this weekend that would effectively block a N/NW track. Models tend to have less ridging than what actually transpires...we have seen this time and time again. I certainly think this could get into the SE/E Gulf at least. There are some negative factors for 99L to overcome...the biggest being dry air and maybe some shear if the GFS is correct on its upper air strung out trough over the SW ATL. Model consistency is in the dumps between both runs and the different models so they are of little help...but there is fair agreement on the overall pattern that will be in place....a lot of ridging! Ensembles can be of better help with the current situation and many of them are showing the W to WNW bend over the Bahamas as whatever is there feels the ridging to the NW.
Andrew wrote:Just for reference, the HWRF shows a strong hurricane NE of the Bahamas . GFDL barely has a tropical low approaching the Bahamas
And nothing approaching TX, I presume.
HWRF doesn't go far enough out. Still too soon to say really, but trend is closer to a gulf coast storm if it develops.
Dear Andrew and Worrybug.
I'm not going to get hung up on any one scenario, here, but, based on the recent changes in the steering forecast, I think residents of the Florida Peninsula and Mobile, Al., as well as all other E Gulf communities, should monitor the progress of 99L, if/when it becomes better organized and develop into a tropical cyclone over the next 5 days. No one I've spoken to thinks this is eventually going to be a TX storm, though there aren't any guarantees on that.
jeff wrote:A lot of strong ridging in the extended range along the E coast. Heights of 591 to 594dm over the SE US this weekend. Ensemble tracks are more important at this juncture than the operational runs. Hard to find a way for this to escape north with the forecasted steering pattern in place on many of the models. Something to watch.
Jeff should the Houston/Galveston area be paying attention to 99L.
It is always good to keep an eye on things...most of us would have never thought Ike would get here from where it was when it formed. I don't like the fact that there is fair agreement on a good amount of ridging over the SE US this weekend that would effectively block a N/NW track. Models tend to have less ridging than what actually transpires...we have seen this time and time again. I certainly think this could get into the SE/E Gulf at least. There are some negative factors for 99L to overcome...the biggest being dry air and maybe some shear if the GFS is correct on its upper air strung out trough over the SW ATL. Model consistency is in the dumps between both runs and the different models so they are of little help...but there is fair agreement on the overall pattern that will be in place....a lot of ridging! Ensembles can be of better help with the current situation and many of them are showing the W to WNW bend over the Bahamas as whatever is there feels the ridging to the NW.
Unfortunately, I've just seen the GEFS and it's showing a big cluster over New Orleans, LA. I don't like that.
Models responding to the synoptic scale pattern of strong ridging showing more and more leftward trending. Ensembles have been split between a west track into the Gulf and N track toward the SE US coast over the last 48 hours. It is becoming clear that the leftward track is increasingly the more likely outcome. Still not overly worried about intensity just yet even with the strong EURO and HWRF runs...but think the GFS is too weak. Factors certainly to overcome in the next 48-72 hours for development.
Fiona is expected to turn northwestward with some deceleration as it heads for a break in the subtropical ridge. The official track forecast is very close to the latest dynamical model consensus, TVCN.
jeff wrote:Models responding to the synoptic scale pattern of strong ridging showing more and more leftward trending. Ensembles have been split between a west track into the Gulf and N track toward the SE US coast over the last 48 hours. It is becoming clear that the leftward track is increasingly the more likely outcome. Still not overly worried about intensity just yet even with the strong EURO and HWRF runs...but think the GFS is too weak. Factors certainly to overcome in the next 48-72 hours for development.
But it has to clear Florida first if I read the models right. I had a gut feeling that people on the E Gulf Coast (at least) would be the ones to have to really watch it.
jeff wrote:Models responding to the synoptic scale pattern of strong ridging showing more and more leftward trending. Ensembles have been split between a west track into the Gulf and N track toward the SE US coast over the last 48 hours. It is becoming clear that the leftward track is increasingly the more likely outcome. Still not overly worried about intensity just yet even with the strong EURO and HWRF runs...but think the GFS is too weak. Factors certainly to overcome in the next 48-72 hours for development.
But it has to clear Florida first if I read the models right. I had a gut feeling that people on the E Gulf Coast (at least) would be the ones to have to really watch it.
Right now everyone needs to keep an eye on it but don't worry too much about it. There are a lot of questions to be answered and few solutions. Hopefully by the middle of the week we have a better idea of what will happen.
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jeff wrote:Models responding to the synoptic scale pattern of strong ridging showing more and more leftward trending. Ensembles have been split between a west track into the Gulf and N track toward the SE US coast over the last 48 hours. It is becoming clear that the leftward track is increasingly the more likely outcome. Still not overly worried about intensity just yet even with the strong EURO and HWRF runs...but think the GFS is too weak. Factors certainly to overcome in the next 48-72 hours for development.
But it has to clear Florida first if I read the models right. I had a gut feeling that people on the E Gulf Coast (at least) would be the ones to have to really watch it.
Right now everyone needs to keep an eye on it but don't worry too much about it. There are a lot of questions to be answered and few solutions. Hopefully by the middle of the week we have a better idea of what will happen.
May I please share a personal landfall guess (big G) with you?
