Ed Dunham
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| (Former Meteorologist & CFHC Forum Moderator (Ed Passed Away on May 14, 2017)) |
| Thu Sep 18 2008 03:56 AM |
North of Antigua
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A new tropical wave is firing a burst of convection north of Antigua. The wave is under light southerly wind shear and has very little movement - perhaps a slow westerly drift. Elsewhere the Atlantic Basin is tranquil.
ED
Added: Not really a tropical wave after all - its a developing upper level low with a difluent zone that is enhancing convection over the Islands. However, enhanced convection north of Panama is associated with a tropical wave.
| doug |
| (Weather Analyst) |
| Thu Sep 18 2008 02:47 PM |
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Re: North of Antigua
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The southwestern Carribean has been under a generalized area of lower pressure for a while. The models show this but nothing is supposed to popup in the near future. However, this is the area we will need to watch more now that we are moving past the peak Atlantic season. Some hefty late season storms have developed here (Mitch comes to mind.)
(It is interesting that today's discussion did classify the activity north of Antigua as a wave interacting with an upper low and indicated a low level of probability for development.)
| Ed in Va |
| (Weather Master) |
| Thu Sep 18 2008 07:13 PM |
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Re: North of Antigua
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There have been models and discussions about possible development off the east coast next week. Here is the
Wilmington NC take on it:
AN INTERESTING ASPECT TO CONSIDER WITH THIS SCENARIO IS HOW MANY
TROPICAL CHARACTERISTICS A SLOW-MOVING FRONTAL LOW COULD PICK UP
WHILE OVER THE GULF STREAM FOR SEVERAL DAYS. THE HPC EXTENDED
DISCUSSION GIVES MORE DETAILS ABOUT POSSIBLE IMPACTS SHOULD AN
SUBTROPICAL TRANSITION OCCUR. MORE MUNDANE TO CONSIDER...BUT
SITUATIONS SUCH AS THESE OFTEN WRAP CONSIDERABLE DRY AIR IN FROM THE
NORTH WHICH LIMITS THE WEST AND NORTHWESTWARD PENETRATION OF RAIN.
THE UPPER LOW INLAND MAY MITIGATE THIS SOME...BUT MANY POSSIBILITIES
REMAIN OPEN. SINCE THIS IS STILL A 6 AND 7 DAY FORECAST WE HAVE ONLY
RAISED POPS 10-20% ABOVE CLIMATOLOGY UNTIL DETAILS CAN GET HAMMERED
OUT OVER THE NEXT FEW DAYS.
Here's the actual HPC discussion"
...UPDATED MORNING PRELIMS PROVIDE IMPUT FROM 06Z GFS/DGEX AND
ECMWF ENS MEAN..CHANGES MADE ARE TO GO COMPLETELY WITH ECMWF BUT
WITH MODIFICATIONS TO ITS SFC PRESSURE FIELDS ACROSS THE EAST
COAST DAYS 6 AND 7 MORE TOWARD A CONSENSUS OF OP MODELS TOWARDS
MORE HIGH PRESSURE OVER NEW ENGLAND COMBINED WITH THE POTENTIAL OF
SUBTROPICAL LOW/HYBRID TYPE SFC WAVE DEVELOPMENT OFF THE SOUTHEAST
COAST INCREASING THE WIND FIELDS TO FULL GALE OR STORM CONDITIONS
LATE NEXT WEEK ACROSS THE MID ATLC AND SOUTHEAST COAST. DGEX AND
CMC INDICATE FULL BLOWN TROPICAL CYCLOGENESIS WHILE EVEN THE MOST
CONSERVATIVE OF THE SOLUTIONS DEVELOPS LOW PRESSURE AS DO THE ENS
MEANS. BELIEVE IT PRUDENT TO START LEANING TOWARDS THE MORE
SIGNIFCANT THREAT. THIS IS ALSO SUPPORTED BY A WESTERLY PHASE MJO
AND FAVORABLE VELOCITY POTENTIAL ANOMALIES AT H250 AND H850
COVERING AN AREA INCLUDING THE TROPICAL EPAC/GULFMEX/CARRIBBEAN
AND OFFSHORE OF THE SOUTH ATLC SEABOARD/BAHAMAS.
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Ed Dunham
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| (Former Meteorologist & CFHC Forum Moderator (Ed Passed Away on May 14, 2017)) |
| Thu Sep 18 2008 08:44 PM |
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Re: North of Antigua
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Interesting discussions. The HPC comments may be influenced by what appears to be the remnant low-level circulation of the former 'Josephine'. The circulation is still intact near 23.2N 67.3W at 18/20Z moving to the west northwest at about 10 knots. Occasional convection is still firing to the northeast of the center and windshear ahead of the system is forecast to decline in the next 48 hours.
ED
| Cat 5orBust |
| (Weather Hobbyist) |
| Fri Sep 19 2008 01:42 AM |
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Re: North of Antigua
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we have 93L now. Need to wait for some more computers to run, but the few that have run (BAMS) AND CMC take it over Hispaniola.
| Taz16 |
| (Registered User) |
| Fri Sep 19 2008 06:52 AM |
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Re: North of Antigua *Killed -- Sent to Graveyard*
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This post was sent to the Hurricane Graveyard
| Ed in Va |
| (Weather Master) |
| Fri Sep 19 2008 06:19 PM |
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Re: North of Antigua
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Today's HPC discussion on possible EC storm next week...maybe more of a northeaster than a tropical system:
THE ATLC COASTAL SIGNAL HAS BEEN SEEN FOR SEVERAL DAYS NOW PLACING
A 1035-1040 MB HIGH IN A POSITION TO PROVIDE NEAR GALE FORCE WINDS
IN THE WEST ATLC AND ALONG THE COAST ALONE. ALL MODELS AND
ENSEMBLES HAVE INDICATED SOME CYCLOGENESIS POSSIBLY EVEN A
SUBTROPICAL LOW. GFS SERIES HAS BEEN ON THE RIGHT SIDE OF THE
ENVELOPE WHILE CANADIAN AND DGEX HAVE BEEN MORE TO THE LEFT.
PREFERENCE IS TOWARD ECMWF/UKMET AND LATEST DGEX OF LOW PRESSURE
DEVELOPING OFF THE GA COAST MOVING NWD TO ALONG THE MID ATLC COAST
LATE WEEK/NEXT WEEKEND. THIS WILL BRING BRISK/STRONG ONSHORE WINDS
TO THE MID ATLC SOUTHEAST COAST TUES INTO FRIDAY AND NWD UP THE
COAST NEXT WEEKEND. THREAT OF GALE TO STORM FORCE COASTAL AND
OFFSHORE WINDS/PROLONGED PERIOD OF HIGH TIDES WITH ENHANCEMENT BY
NEW MOON PHASE/COASTAL FLOODING/BEACH EROSION/AND HEAVY COASTAL
RAINS. ABOVE AVERAGE CONFIDENCE FORECAST.