cieldumort
Moderator
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Posts: 2497
Loc: Austin, Tx
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With so much attention rightfully on Fay this week, a little-noted tropical wave that rolled off the west coast of Africa a few days ago has been on a fast track ramp-up tonight.
At this time microwave passes are still a bit wanting, and the most recent out of SAB came in 1.0. The most recent scatt winds came in many hours ago, and a fairly well-defined surface circulation was already present at that time.
It is very possible that the estimate out of SAB is, now, already obsolete, despite being less than a few hours old. Using a blend of both the curved band and methods, and even adjusting this down by applying a degree of constraint (.3T/hr), a more timely Current Intensity (CI) might be in the neighborhood of 2.0 - and it is entirely possible that a tropical cyclone has been forming tonight.
From the 2AM EDT , Berg & Franklin give it marks for increased convection, but stress the expectation that upper-level winds become unfavorable in a few days. In an effort to play devil's advocate, I'll point out that 72 hours from now has nothing to do with what the conditions for development are, right now.
There remains much question as to how stacked the surface low is with the robust mid-level center that has really blossomed over the past six hours. Critical to whether or not the feature is, in the first place, a developing tropical cyclone, and going forward, how it will react to a potentially increasingly hostile upper-level wind environment, will be some more microwave, scat passes, and daylight.
The model runs favoring a relatively rapid and pronounced development of 94L tend to find it a weakness in the B/A High, and send it off fishing. Others, which either keep it from developing for many days, or develop it but keep it on the weaker side, unsurprisingly direct it towards the Greater Antilles.
We should know much more by midday.
Midday Edit
After a very good try overnight, morning hasn't been kind to 94L. There is some reason to believe that with the cooling atmosphere at night, it may just be that for the next few the disturbance continues to fare better at night, but then worse entering the next day. If the disturbance hasn't bitten the dust within the next 120 hours or so, at some point in this cycle, it may actually blow up enough to gel.
Track wise, as it now appears 94L probably will not become a tropical cyclone quickly, steering currents will tend to keep pushing it farther west.
Edited by cieldumort (Tue Aug 19 2008 11:37 AM)
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Major7
Weather Watcher
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Posts: 37
Loc: Hollywood, FL 26.02N/80.20W a...
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Visions of 2004 are starting to pop into my head.
I remember reading somewhere that closely-timed storms tend to follow in previous storm's track. Is this true? And why?
Edited by Major7 (Tue Aug 19 2008 02:26 PM)
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cieldumort
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Posts: 2497
Loc: Austin, Tx
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Let's hope for everyones sake that a repeat of 2004 isn't in the cards.
At least Florida has picked up some helpful servings of rain. Very generous servings, eh?
As for closely-timed storms following the same path, it almost certainly has to do with the steering currents which navigated the first storm still being about the same by the time a "closely-timed" storm comes along. This isn't always the case, of course, but it has happened plenty of times with storms that are closely-timed and just close to each other.
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Major7
Weather Watcher
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Posts: 37
Loc: Hollywood, FL 26.02N/80.20W a...
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That makes sense. Thanks.
-------------------- My experiences:
Betsy 1965~New Orleans (my first)
Alicia 1983~Texas; Opal 1995~Georgia;
Frances & Jeanne 2004~Florida;
Dennis, Eye of Katrina, Eyewall of Wilma~Florida 2005
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craigm
Storm Tracker
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Posts: 327
Loc: Palm City, Florida
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Here an interesting excerpt from NWS puerto rico.
'SYNOPTIC PATTERN ACROSS
THE TROPICAL ATLC REMAINS VERY INTERESTING TODAY...WITH WELL
ESTABLISHED MONSOON TROUGH HAVING BROKEN FREE OF AFRICAN MONSOON
GYRE...THANKS TO A LARGE BAROCLINIC LOW HAVING MOVED ACROSS THE
CAPE VERDES PAST 24-36 HOURS...AND STRONG WLYS SOUTH OF TROUGH NOW
FLOWING SW TO NE AND INTO E SIDE OF THIS BROAD AND ELONGATED LOW.
A CLUSTER OF DEEP CNVTN AND MID LEVEL CYCLONIC TURNING CAN BE SEEN
ALONG ABOUT 9N 35W THIS MORNING ON S SIDE OF THIS EVOLVING
FEATURE. WLYS S OF THE MONSOON TROUGH NOW EXTEND FROM THE MID 50S
TO THIS LARGE TROPICAL WAVE CROSSING 30W THIS MORNING. TROPICAL
WAVE APPROACHING THE LESSER ANTILLES LOOKS TO BE ALONG 53/54W ATTM
AND GAINING POSITIVE TILT WITH TIME...AS MID LEVEL JET REMAINS
ALONG 18-20N. THIS ALIGNMENT CONTINUES TO BLEED VORTICITY AND
MOISTURE TO THE AMBIENT FLOW...WITH LEADING EDGE OF RELATED
MOISTURE JUST ABOUT TO REACH 60W ATTM. NOT FORECASTING THIS
AREA OF WEATHER TO REACH THE USVI UNTIL 06-12Z FRIDAY...BUT SOME
LEADING MOISTURE LIKELY TO AFFECT THE LOCAL AREA TONIGHT. AS HAS
BEEN THE CASE ACROSS THE LOCAL REGION FOR MUCH OF THE PAST 30-60
DAYS...STEERING FLOW IS FORECAST TO GUIDE MUCH OF THE MOISTURE AND
ENERGY ASSOCIATED WITH THIS APPROACHING WAVE TO THE WNW AND
NW...AND LIFT N OF PUERTO RICO...JUST BRUSHING THE VIRGIN ISLANDS.
HOWEVER...CYCLONIC TURNING SEEN IN IR IMAGERY OVERNIGHT CENTERED
ALONG 12N 52W DOES NOT APPEAR WELL INITIALIZED BY ...AND THIS
MAY PASS JUST SOUTH OF PR FRI NIGHT-SAT TO IMPACT THE ISLAND MUCH
MORE SIGNIFICANTLY THAN CURRENTLY SUGGESTED. AGAIN...THIS COMPLEX
TROPICAL ENVIRONMENT ACROSS THE ATLC PROVING CHALLENGING FOR THE
GLOBAL MODELS AND THE NEXT WEEK AND BEYOND SHOULD BE INTERESTING.
-------------------- Why I'm here:
Weather hobbyist
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