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8AM EDT Update 29 September 2007 Tropical Depression #14 becomes Tropical Storm Melissa, with 40MPH winds. It is expected to turn north eventually and out to sea, it, much like Karen, will enter high shear in a few days which may weaken or dissipate it. Karen is also undergoing heavy shear, and it's looking more like a tropical wave than a tropical storm this morning. There is a good chance Karen will be considered gone, open up back into an open wave. Two low level circulation centers can be seen on visible satellite imagry. It is very likely Karen has already fallen below depression status. Conditions improve in a day or so, however. Original Update Tropical Depression 14 has formed in the far east Atlantic, from what was a short lived invest 99L that formed this morning. Likely out to sea. More to come on this soon. Advisories for TD#14 should begin at 11AM EDT. Hurricane Lorenzo made landfall this morning along the coast of Mexico. Karen has weakened and may weaken more, it is still most likely to head out to sea, but there are some interesting things going on with it. More to come soon.... Southeast Composite Radar {{radarlink|amx|Miami, FL}} {{radarlink|byx|Key West, FL}} {{radarlink|mlb|Melbourne, FL}} {{StormCarib}} {{StormLinks|Karen|12|12|2007|1|Karen}} {{StormLinks|Melissa|14|14|2007|2|Melissa}} |
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I'm just a hobbyist at best but the NHC made this statement in 11:00 am disc of Karen "...BUT NOW APPEARS TO BE RETURNING TO A PREVIOUS WEST-NORTHWESTWARD MOTION." I just do not see any westward progression at all, in fact the vis sat appears to show a due north movement. Anyway, all for naught, I believe, just do not see Karen surviving much longer in a very hostile enviroment for trop cycl. |
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I got the impression that the NHC was throwing their collective hands in the air and saying, we really don't know what's going to happen. |
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At least for the time being, she has some signs of life, with some convection blow-up this afternoon. |
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reason she went NNE is cause a passing weak shortwave went by. with her moving inline with the shear in the mid-levels she got into a brief less hospitable shear. She should resume a WNW direction. Difficult to see if she will survive the shear...she needs to get past 65W by Monday...shear will start to decrease and she might be a threat..but if she pulses and maintains some sort of organization..she might get pulled more N and then NE with the trough but not as a hurricane..just as a organized weak TS sheared system..(like now). Time will tell. Area that is forecasted to form over the southern Bahamas will be simular to TD 13..more in the mid and upper levels and a weak LLC.....it could become a TS but simular to 13....hard to tell if anything at all. |
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On the last few frames, Karen is moving due WEST, it has stopped it's northward movement and should continue on a west or west - northwestward course. Karen is also surprisingly blowing up convection.. on the CIMMS shear map shear is 10-15 knots where the actual center is, but where the moisture is, it's 30-50 knots. Yesterday, Karen had that "Barry" look when it reached it's peak in June. This should only be temporary but, it makes me believe even more that she will make it through, also the only reason why the 3 models (GFS, GFDL, and UKMET) even dissipate the storm is because they are developing a trough off the East Coast that would absorb Karen up, not buying yet. For a Tropical Storm, she is actually looking really good. http://www.ssd.noaa.gov/goes/flt/t1/sloop-vis.html Tropical Depression 14 literally shocked me this morning.. I found out it was tagged an invest early this morning and then a TD at 11 am. this should stay out to sea, but wouldn't surprise me if it were to head to Bermuda in the long term. |
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The BAM series has changed its tune and now is moving Karen NE out to sea after a NW turn. Any ideas why? |
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Some models are showing a trough off the southeast coastline shoving Karen out to sea "again".. I'm not buying these models yet, Karen is maintaining her convection for now, but unless something amazingly happens, it will die out tonight and possibly come back again tommorrow. this proccess will continue until shear lightens up, which should be in a few days. Until I see more model support and the actual trough, I am sticking with a westward motion. |
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I'm not seeing that with the recent BAM-series model runs for Karen. I see a NW-then-NE motion with TD 14, however; perhaps you're getting one mistaken for the other? The relevant BAM-series model runs: Karen TD 14 (NE motion appears better on the 18z runs) |
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Karen lives on! Well, kinda..... I think we need a new designation and will make the pitch to NHC! In addition to extra-tropical and sub-tropical, I believe the need exists for a new acronym which would expand the commonly used TD, TS, and HURR. Hmmm, how 'bout "REFUSING TO DIE" or "RTD" - " for " Weakened Tropical Cyclone Having NO Closed Circulation Containing Winds Less Than 25mph, Where Models Predict Hurricane Strength in 72 hrs. or Less!! KIdding of course........, Per recent NHC discussion, along with the obvious, Karen joins the ranks of Tropical "Has-Beens" refusing to die. Amazing how some dynamic models remain quick to restrengthen Karen in a few days. What will be left to strengthen though? I give up attempting to think I have a real handle on this one, but one thing for sure, given Karen's originally large envelope, it would stand to reason that it would take longer to "unwind" than most smaller tropical cyclones. If Karen were to get picked up and move north to northeast, than I could far easier see re-intensification, as motion would lessen the impact of shear. I just do not see a remnant surface to 850mb reflection of Karen, moving west to WNW 3 days from now; meanwhile re-intensifying. Either a westward moving remnant low, or a soon to be mid latitude extra tropcal hurricane moving away from the CONUS. Sitting here, suffering from "Tropcal Envy" as well as "Tropical Cyclone Fatigue" along with making an observation, i'll toss out this interesting and perhaps utterly and useless factoid: 70% , or 9 out of the 13 ( ok, am exaggerating is actually 69% ) of all named tropical cyclones this year, have passed within approx. 700 miles of Havana, Cuba. Point being, that conditions thus far, and quite soon climatology itself, would indicate where the majority of remaining activity might yet occur. With this, I am going to turn my attention to what I believe to be the next INVEST . For the sake of Forum continuity, however will initiate a new thread in the Forecast Lounge to discuss what I believe to be the next system to watch. |
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MODEL DIAGNOSTIC DISCUSSION NWS HYDROMETEOROLOGICAL PREDICTION CENTER CAMP SPRINGS MD 121 PM EDT SAT SEP 29 2007 VALID SEP 29/1200 UTC THRU OCT 03/0000 UTC MODEL TRENDS... ...DEEP CYCLONE/POSSIBLY SUBTROPICAL LOW RETROGRADING ACROSS FLORIDA... THE NAM HAS TRENDED DEEPER/MORE RETROGRESSIVE WITH THIS SYSTEM OVER ITS PAST DAY OF RUNS...PARTIALLY DUE TO STRONGER RIDGING NEAR THE NORTH CAROLINA/VIRGINIA BORDER. THE ECMWF HAS TRENDED MORE SOUTHWEST WITH THIS SYSTEM OVER ITS PAST COUPLE DAYS OF RUNS DUE TO STRONGER RIDGING OVER THE MID-ATLANTIC STATES. THE GFS HAS BEEN CONSISTENT IN KEEPING MOST OF THE ENERGY WITHIN THE TROUGH WEST OF BERMUDA WHICH THEN RECURVES NORTHEASTWARD...ALLOWING A MUCH WEAKER PIECE OF ENERGY TO RETROGRADE THROUGH THE SOUTHERN GULF OF MEXICO. MODEL DIFFERENCES AND PREFERENCES... ...DEEP CYCLONE/POSSIBLY SUBTROPICAL LOW RETROGRADING ACROSS FLORIDA... NORMALLY...WHEN A MERIDIONAL RIDGE REORIENTS ON A MORE EAST-WEST AXIS...A CLOSED CYCLONE WILL EMERGE FROM THE BASE OF THE PREVIOUS TROUGH UNDER THE RIDGE AND RETROGRADE. THE CANADIAN...NAM...ECMWF...AND UKMET SHOW THIS IDEA. THE GFS ALLOWS A BULK OF THE ENERGY TO BE INITIALLY TRAPPED NEAR THE COL POINT IN THE UPPER PATTERN BEFORE LIFTING NORTHEAST AHEAD OF THE NEXT SHORTWAVE. WILL REJECT THE GFS SOLUTION AS IT DOES NOT FIT THE ABOVE THINKING. THE CANADIAN IS NOT MUCH BETTER...ALLOWING A SHORTWAVE TO INDUCE A MODERATELY STRONG SURFACE LOW THAT THEN TRACKS TOWARDS THE CAROLINAS. SINCE THE BULK OF THE ENERGY SHOULD BE RETROGRADING THROUGH THE FLORIDA KEYS INTO THE SOUTHEAST GULF OF MEXICO...THINK THIS CYCLONE IS TOO DEEP AND TOO FAR REMOVED FROM WHERE THE UPPER CENTER IS EXPECTED TO BE. THE UKMET COUPLES THIS SYSTEM IS AS FAR WEST AS THE WEAK 12Z GFS...BUT WITH A DEEPER CENTRAL PRESSURE. THE FORECAST GUIDANCE TENDS TO RETROGRADE CLOSED CYCLONES IN THE SUBTROPICS TOO QUICKLY. SO...FOR NOW...WILL FAVOR THE ECMWF SOLUTION BASED ON THE ABOVE REASONING. MODEL DIAGNOSTIC DISCUSSION edit: This probably should have been posted in the Forecast Lounge. Since the future system is currently impacting the FL East Coast, to a degree. I'll leave the decision to move it up to MikeC and ED.~danielw |
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Just wondering if anyone has any theories about the number of lower latitude systems that have cranked up, while those in the upper latitudes have been blown out with upper and mid shear. The curious thing about that being, that this is the kind of activity in the more northerly latitudes you would expect in an ENSO season and not in a LNSO season. Is this just a temporary anomaly or is this maybe some kind of hybrid season between the two? A Met friend, Paul Dellagato (WTVT-TV-Fox in Tampa), is doing some over the weekend research on this phenomena. But we both find this somewhat of a curiosity. Anybody want to throw their hat in the theory ring? |