LakeEffectKing Posted September 2, 2011 Share Posted September 2, 2011 IMO, TD 13 and it's ultimate evolution is of utmost importance...moreso than any DS ridging, regarding an EC hit...and kind of agree with Adam that a NE hit would be quite difficult without such a ridge....the timing would need to be perfect with a rather quick NW motion of a TC.... But for a NC hit or south, TD 13, IMO needs to strengthen a good bit and then move inland to about the MS/LA border and stall and start transitioning to a baroclinic system, which should certainly induce an downstream ridge (much like what is depicted in the 18z GFS)...and with a weaker Katia than what was progged earlier for this time, and a pick up in speed by a knot or two over the next 3-5 days, and the threat level for the SE coast goes up substantially. If one was "looking" for a better chance in the models of an EC threat, today served some improvement....And coupled with a weaker Katia, and the threat has increased modestly from yesterday. Link to comment Share on other sites More sharing options...
free_man Posted September 2, 2011 Share Posted September 2, 2011 I was taking a look at the daily composites of Edna, Carol, Gloria and Bob, and Irene...I think the correlation with Nova Scotia/Labrador height anomaly is stronger. Both Bob and Carol did not feature ridging in the Davis Strait area, Bob especially. Link to comment Share on other sites More sharing options...
OSUmetstud Posted September 2, 2011 Share Posted September 2, 2011 those dates aren't hurricane hits Link to comment Share on other sites More sharing options...
Typhoon Tip Posted September 2, 2011 Share Posted September 2, 2011 What is with all the comments implying any sort of certainty in models 8-10 days out? Not that I don't agree but the reasoning for the re-curve solution is climo, not the GFS prognostics 2 weekends from now. What is meant by that statement (bold)?? Climo doesn't "cause" things to happen - you do realize that, right? Climatology is essentially the sum of all events devided by n events in the most basic sense. You can look at a given storm and compare it to that climatology, and provided the climatological study has a sufficiently large sample of events in its mean, you "might' be able to derive a sense of confidence in a forecast one way or the other based on how it compares. But therein is risk, as well, because a given single synoptic pattern really couldn't give two schists what climo says, it's going to do what it's going to do. This is the primary reason I don't like to try and assert confidence in recurve this, or straight west that based merely on what other systems did at a given starting position in time. Climate really only gives a canvas so to speak, on which an event gets painted - the end picture often enough won't look the same. Link to comment Share on other sites More sharing options...
OSUmetstud Posted September 2, 2011 Share Posted September 2, 2011 Agreed... its either/or ahh right okay...Bob is a little odd compared to the others in that features pretty strong zonal flow across the North Atlantic...obviously still had strong ridging south of there in the Nova Scotia/Labrador area. Irene is very odd anyway since it's the only one that didn't feature the classic MW/OV/TV trough Link to comment Share on other sites More sharing options...
Typhoon Tip Posted September 2, 2011 Share Posted September 2, 2011 Looks transient in Davis Straight The west ridge just plows east too fast on most runs t which is the second problem with the setup for the EC. Speaking relative to the GFS runs alone ... I think the difference there for the EC really comes down to the middle latitude features here... The NAO is somewhat positive averaging the two agencies, leaving the influence of core of the westerlies primarily N of the boarder over eastern N/A. That leaves the details in the tussle between Atlantic subtropical ridge against the timing of oscillations in the OV/MA trough as more instrumental in the eventual track evolution of Katie.The 18z is more robust with the seaward ridge, while simultaneously somewhat deeper with the trough in the upper TV valley; the path of least resistance there is simple a more westward track than the previous cycle. <br><br>We're probably going to have this east west east west yo-yo game for a couple few more days.<br> Link to comment Share on other sites More sharing options...
BethesdaWX Posted September 2, 2011 Share Posted September 2, 2011 What is meant by that statement (bold)?? Climo doesn't "cause" things to happen - you do realize that, right? Climatology is essentially the sum of all events devided by n events in the most basic sense. You can look at a given storm and compare it to that climatology, and provided the climatological study has a sufficiently large sample of events in its mean, you "might' be able to derive a sense of confidence in a forecast one way or the other based on how it compares. But therein is risk, as well, because a given single synoptic pattern really couldn't give two schists what climo says, it's going to do what it's going to do. This is the primary reason I don't like to try and assert confidence in recurve this, or straight west that based merely on what other systems did at a given starting position in time. Climate really only gives a canvas so to speak, on which an event gets painted - the end picture often enough won't look the same. Of course, I was implying/saying that the reason we can say more definitively that a re-curve is likely a this range is Katia's Lattitude & the forward motion present, & what climo usually says/dictates here, at this range, can give us a more conclusive answer than models can...that is what I meant by that. Basically implying that at this range climo should be weighted into forecasts a bit, over a week out. Link to comment Share on other sites More sharing options...
metagraphica Posted September 2, 2011 Share Posted September 2, 2011 Meanwhile, it looks like the shear and dry air have relaxed a bit this evening for Katia. Link to comment Share on other sites More sharing options...
Typhoon Tip Posted September 2, 2011 Share Posted September 2, 2011 Of course, I was implying/saying that the reason we can say more definitively that a re-curve is likely a this range is Katia's Lattitude & the forward motion present, & what climo usually says/dictates here, at this range, can give us a more conclusive answer than models can...that is what I meant by that. Basically implying that at this range climo should be weighted into forecasts a bit, over a week out. I guess I'm being a bit persnickety with the terminology you are using but ,.. .climo doesn't dictate anything. I think what you means is climate indicates greater probability of re-curve. No arguement there... We'll just have to wait and see if the synoptics of the here and now cooperate with that Link to comment Share on other sites More sharing options...
Typhoon Tip Posted September 2, 2011 Share Posted September 2, 2011 Meanwhile, it looks like the shear and dry air have relaxed a bit this evening for Katia. Yes, I was just looking at this... Extrapolating off the 49.2/16.1 fix from 5pm I estimate the current position is now under the southern edge of that quasi-CDO feature... One thing to maybe consider... When it weakened due to shear (arguably some dry air entraining) earlier on it left a decent low pressure in tact. When/if the shear relaxes the response may be almost immediate - that may be underway already. Link to comment Share on other sites More sharing options...
donsutherland1 Posted September 2, 2011 Share Posted September 2, 2011 At this time, I believe that Katia has weakened a little more from earlier this afternoon. I would not be surprised if the NHC has lowered its estimated maximum winds to 65 mph. An area of strengthening shear currently at 15-20 knots covers Katia's northern circulation. However, to its west, the shear has been relaxing. As Katia tracks generally west-northwestward overnight into tomorrow, it will gradually move into an environment that could become more favorable for restrengthening. Before then, some additional weakening might be possible overnight. Its lack of growth will likely limit any turn to the north in the near-term. That could translate into Katia's coming farther to the west. At this time, I still believe Katia has about a 60% chance of recurvature. However, the combination of its weaker strength and prospect that ridging will close the weakness for a time increases prospects of its tracking more to the West. Previously, I had thought that 65W-70W would be about as far as Katia gets before it recurves. Odds of its reaching at least 70W-75W have increased. In a worst-case scenario, Katia could continue to track mainly west to west-northwestward until it gets so far to the west that its turn to the north comes too late to avoid landfall. Floyd (1999) is an example of such a storm. Right now, I do not expect a Floyd-like outcome. But I can see Katia passing near 20.0N 57.6W, 25.0N 67.6W, and 30.0N 71.7W at this time. The first two positions would be about 50 and 210 miles west of the 9/1 5 pm NHC track. A delayed turn northward from a weaker Katia has raised prospects of such a track. Link to comment Share on other sites More sharing options...
Thundersnow12 Posted September 2, 2011 Share Posted September 2, 2011 Link to comment Share on other sites More sharing options...
Typhoon Tip Posted September 2, 2011 Share Posted September 2, 2011 At this time, I believe that Katia has weakened a little more from earlier this afternoon. I would not be surprised if the NHC has lowered its estimated maximum winds to 65 mph. An area of strengthening shear currently at 15-20 knots covers Katia's northern circulation. However, to its west, the shear has been relaxing. As Katia tracks generally west-northwestward overnight into tomorrow, it will gradually move into an environment that could become more favorable for restrengthening. Before then, some additional weakening might be possible overnight. Its lack of growth will likely limit any turn to the north in the near-term. That could translate into Katia's coming farther to the west. At this time, I still believe Katia has about a 60% chance of recurvature. However, the combination of its weaker strength and prospect that ridging will close the weakness for a time increases prospects of its tracking more to the West. Previously, I had thought that 65W-70W would be about as far as Katia gets before it recurves. Odds of its reaching at least 70W-75W have increased. In a worst-case scenario, Katia could continue to track mainly west to west-northwestward until it gets so far to the west that its turn to the north comes too late to avoid landfall. Floyd (1999) is an example of such a storm. Right now, I do not expect a Floyd-like outcome. But I can see Katia passing near 20.0N 57.6W, 25.0N 67.6W, and 30.0N 71.7W at this time. The first two positions would be about 50 and 210 miles west of the 9/1 5 pm NHC track. A delayed turn northward from a weaker Katia has raised prospects of such a track. You may be right about that weakening trend; often times we see that robust regeneration of convection and actual intensity realization are off-set where the former leads the latter somewhat. ...For that matter, sometimes the awesome appeals of satellite reflect little change in actual intensity, too. But, this is/was 990mb and a respectable depth when the towers tilted off the llv vortex. When the shear relax any it will likely erupt rather abruptly. Link to comment Share on other sites More sharing options...
donsutherland1 Posted September 2, 2011 Share Posted September 2, 2011 But, this is/was 990mb and a respectable depth when the towers tilted off the llv vortex. When the shear relax any it will likely erupt rather abruptly. I agree. I still expect Katia to become a major hurricane (probably peaking at Category 4. Category 5 is still somewhat of a possibility). Link to comment Share on other sites More sharing options...
Typhoon Tip Posted September 2, 2011 Share Posted September 2, 2011 I agree. I still expect Katia to become a major hurricane (probably peaking at Category 4. Category 5 is still somewhat of a possibility). E-gads! Cat 4 would be fantastic. Those upper echelons really require closer to ideal settings - as you were saying, that may not be fore 24 hours before that happens. At leasw according to the modeling. Link to comment Share on other sites More sharing options...
Typhoon Tip Posted September 2, 2011 Share Posted September 2, 2011 NHC is also discussing the trough-ridge relationship between 90W and the Atlantic heights... I think the details of that will be instrumental in determining where this goes... HOWEVER...IN THE LONG RANGE...A STRONG MID-LEVEL TROUGH IS FORECAST TO DEVELOP OVER THE GULF OF MEXICO AS THE ATLANTIC SUBTROPICAL RIDGE BUILDS WESTWARD. THIS PATTERN SHOULD FORCE KATIA ON A MORE WEST-NORTHWESTWARD MOTION BY THE END OF THE FORECAST PERIOD AS INDICATED BY THE ECMWF AND THE GFS. THIS SMALL BEND TO THE WEST-NORTHWEST IS REFLECTED IN THE OFFICIAL FORECAST. Link to comment Share on other sites More sharing options...
BethesdaWX Posted September 2, 2011 Share Posted September 2, 2011 I guess I'm being a bit persnickety with the terminology you are using but ,.. .climo doesn't dictate anything. I think what you means is climate indicates greater probability of re-curve. No arguement there... We'll just have to wait and see if the synoptics of the here and now cooperate with that Well "dictate" was crappy word choice on my part. Climo should be weighted higher in the longer ranges IMO, dictating one's forecast track...more-so than model consensus which changes run to run, and trends over several runs on occasions like we saw with Irene. Maybe the synoptics don't cooperate and Savannah gets plastered, but forecasting that, or anything other than a fish storm atm, would be sillyness, just imfo. Link to comment Share on other sites More sharing options...
Typhoon Tip Posted September 2, 2011 Share Posted September 2, 2011 Well "dictate" was crappy word choice on my part. Climo should be weighted higher in the longer ranges IMO, dictating one's forecast track...more-so than model consensus which changes run to run, and trends over several runs on occasions like we saw with Irene. Maybe the synoptics don't cooperate and Savannah gets plastered, but forecasting that, or anything other than a fish storm atm, would be sillyness, just imfo. Yes in the absence of a coherent synptic signal climo can be useful; but one needs to be ready to make an ulteration to that in a real hurry should said synoptics begin to appeal. Link to comment Share on other sites More sharing options...
Typhoon Tip Posted September 2, 2011 Share Posted September 2, 2011 wow, if you loop the WV imagery right now ( http://www.ssd.noaa.gov/goes/east/tatl/flash-wv.html ) you can see gravity wave action rippling out ahead of Katie through the southern flanks of the trough situated just NW of her - cool! Link to comment Share on other sites More sharing options...
NaoPos Posted September 2, 2011 Share Posted September 2, 2011 Surprised no one mentioned the 0z gfs. West trend continues. Portions of cape cod get precipitation from katia. Posting from my iPhone, but if anyone wants to elaborate further, go ahead. Link to comment Share on other sites More sharing options...
stormspotterlive Posted September 2, 2011 Share Posted September 2, 2011 Surprised no one mentioned the 0z gfs. West trend continues. Portions of cape cod get precipitation from katia. Posting from my iPhone, but if anyone wants to elaborate further, go ahead. Very interesting GFS run here its a Nightmare for any one who got hard hit from Irene on the east coast (NJ). whats left of Lee transfers to Katia but also keeps it from the coast if Lee was to be say 50 miles west we would have an east coast hurricane and major rain storm. additionally ridiging looks slightly better for Katia. GFS ensembles and euro will be very interesting also if the trend continues we could come close to a SC/NC boarder hit then up lots of time here. Not like its a day or 2 way its a week+ this defiantly has me questioning out to sea now and what just may happen with Katia. Going to be a long next 7+ days. Link to comment Share on other sites More sharing options...
LovintheWhiteFluff Posted September 2, 2011 Share Posted September 2, 2011 Surprised no one mentioned the 0z gfs. West trend continues. Portions of cape cod get precipitation from katia. Posting from my iPhone, but if anyone wants to elaborate further, go ahead. Seemed like it was just a little slower, not really west....about 18 hours. 18z 180hr 0z 192hr Link to comment Share on other sites More sharing options...
SnowGoose69 Posted September 2, 2011 Share Posted September 2, 2011 Its still a very long shot. The disturbance that might be Lee is going to have to develop in nearly a perfect manne rto get Katia to hit the U.S....it may be close but right now I'd say its still well below 50% this is making landfall anywhere. Link to comment Share on other sites More sharing options...
NaoPos Posted September 2, 2011 Share Posted September 2, 2011 You can see the ridging Develops a 594dm contour indicative of a stronger ridge as Katia nears the EC.... And the 588 countour extends outwards towards the eastern side of Cuba, whereas the 18z 588dm height makes to the east side of hispanola. In hindsight, katia is above the lower side of the ridge, and the western* extent of that ridge seems to be in same same lat&long as the 18z... And that's just the eastern half of the picture. That crazy ULL/trough is surely gonna cause forecasting troubles down the road. I mean, we're 180-220 hrs out... ULL's are notioriously difficult to pin outside of 48hrs..td#13 is a huge piece of this puzzle attm, which, quite frankly, puts the whole H5 synoptic pattern, outta my tropical knowledge. Good luck! Link to comment Share on other sites More sharing options...
Thundersnow12 Posted September 2, 2011 Share Posted September 2, 2011 FWIW it looks like Katia moves due west on the GFS from 126-150hr. Link to comment Share on other sites More sharing options...
thewxmann Posted September 2, 2011 Share Posted September 2, 2011 Its still a very long shot. The disturbance that might be Lee is going to have to develop in nearly a perfect manne rto get Katia to hit the U.S....it may be close but right now I'd say its still well below 50% this is making landfall anywhere. Not to mention the timing and the morphology of all the troughs, etc. I think Edouard and Earl would be good "analogs" for the future track of Katia. No longer a certainty that this will fish, though. Link to comment Share on other sites More sharing options...
GaWx Posted September 2, 2011 Share Posted September 2, 2011 I expect that this will do no more than tease the east coast, if that. If it teases, it will probably be one of those storms that just won't go away and frustrates lots of weenies for being so slow to exit. The setup is not one that would typically threaten the east coast. It wouldn't at all surprise me if this ends up being one of those storms hated by weenies all over the land. Link to comment Share on other sites More sharing options...
phil882 Posted September 2, 2011 Share Posted September 2, 2011 wow, if you loop the WV imagery right now ( http://www.ssd.noaa....l/flash-wv.html ) you can see gravity wave action rippling out ahead of Katie through the southern flanks of the trough situated just NW of her - cool! Nice Observation! One of the more obvious examples of deep convection inducing gravity waves I've seen... this happens a lot when you see intense convection go up during the overnight hours. Here is a nice visual aid to help explain whats going on. Look at the undulations occurring well to the west of Katia. This is concurrent with the rapid expansion of convection earlier tonight. Link to comment Share on other sites More sharing options...
GaWx Posted September 2, 2011 Share Posted September 2, 2011 Right on cue, the 0Z Euro once again teases but doesn't hit the east coast as expected. Link to comment Share on other sites More sharing options...
atownwxwatcher Posted September 2, 2011 Share Posted September 2, 2011 00z Experimental FIMY ENK This model since i have been watching it has been consistently showing either an east coast threat or a very near east coast threat .. As of 18 Z and 00z GFS we seen that model starting to go "towards" this direction.. Long time till this one is figured out IMHO Link to comment Share on other sites More sharing options...
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