[Tropical] Tropical Weather Discussion

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AXNT20 KNHC 100004
TWDAT

TROPICAL WEATHER DISCUSSION
NWS TPC/NATIONAL HURRICANE CENTER MIAMI FL
805 PM EDT SAT JUN 09 2007

TROPICAL WEATHER DISCUSSION FOR NORTH AMERICA...CENTRAL
AMERICA...THE GULF OF MEXICO...THE CARIBBEAN SEA...NORTHERN
SECTIONS OF SOUTH AMERICA...AND THE ATLANTIC OCEAN TO THE
AFRICAN COAST FROM THE EQUATOR TO 32N. THE FOLLOWING INFORMATION
IS BASED ON SATELLITE IMAGERY...METEOROLOGICAL ANALYSIS...
WEATHER OBSERVATIONS...AND RADAR.

BASED ON 1800 UTC SURFACE ANALYSIS AND SATELLITE IMAGERY
THROUGH 2315 UTC.

...TROPICAL WAVES...

STRONG WELL DEFINED TROPICAL WAVE FOR EARLY JUNE WHICH WAS ADDED
TO THE 12Z SFC ANALYSIS IS CURRENTLY ALONG 16W S OF 15N. THE
LAST VISIBLE SATELLITE IMAGES AND A 1942 UTC QUIKSCAT PASS
SUGGESTS A LOW PRES CENTER ALONG THE WAVE AXIS AT 8N WITH AN
ESTIMATED CENTRAL PRESSURE OF 1009 MB. IN ADDITION...SURFACE
OBSERVATIONS FROM SENEGAL AND GUINEA INDICATE A SECOND LOW
CENTER...1008 MB AT THE NORTHERN END OF THE WAVE NEAR DAKAR.
BASED ON THE LAST 6-12 HOURS OF MOTION THE WAVE APPEARS TO BE
MOVING W NEAR 20 KT. THE WAVE CONSISTS OF WELL DEFINED LOW TO
MID LEVEL CYCLONIC TURNING WITH SCATTERED MODERATE ISOLATED
STRONG BANDED DEEP CONVECTION MAINTAINING ITSELF NEAR THE
ESTIMATED LOW LEVEL CENTER.

A WEAK LOW AMPLITUDE TROPICAL WAVE IS ALONG 39W S OF 10N MOVING
W 10-15 KT. THIS WAVE IS NOT DISCERNIBLE IN OBS OR SAT
IMAGES...THEREFORE THE PSN REMAINS BASED ON CONTINUITY.
ASSOCIATED SHOWER ACTIVITY IS ISOLATED AT BEST.

A TROPICAL WAVE HAS MOVED INTO THE E CARIBBEAN ALONG 63W S OF
16N MOVING W NEAR 15 KT. WIDELY SCATTERED SHOWER AND TSTM
ACTIVITY APPEARS SOMEWHAT ORGANIZED FROM 12N-17N BETWEEN
55W-62W. NEARLY ALL OF THE ASSOCIATED CLOUDINESS LIES TO THE E
OF THE WAVE AXIS...SHEARED BY STRONG UPPER WESTERLIES.

A TROPICAL WAVE IS IN THE S CENTRAL CARIB ALONG 74W/75W S OF 15N
MOVING W NEAR 15 KT. CYCLONIC TURNING IN THE LOWER CLOUDS
APPEARS TO BE ASSOCIATED WITH THE NORMAL BACKGROUND FLOW AROUND
THE N COAST OF COLOMBIA. ISOLATED SHOWERS/TSTMS ARE WITHIN 120
NM EITHER SIDE OF THE AXIS OVER THE CARIB PORTION. HOWEVER...A
MORE SIGNIFICANT AREA OF SCATTERED MODERATE/ISOLATED STRONG
CONVECTION IS LOCATED OVER THE SW CARIB S OF 14N W OF 77W TIED
TO THE ITCZ AND ALSO BEING ENHANCED BY DIFLUENT SWLY FLOW
SE OF AN UPPER LOW OVER W CUBA.

...THE ITCZ...

ITCZ AXIS IS CENTERED ALONG 5N17W 3N21W 4N30W 2N45W 8N58W.
EXCEPT AS NOTED WITH THE STRONG TROPICAL WAVE DESCRIBED ABOVE
...ISOLATED MODERATE IS WITHIN 90-120 NM N OF THE ITCZ
BETWEEN 30W-38W. SIMILAR ACTIVITY IS FROM 8N-11N BETWEEN 54W-56W.

...DISCUSSION...

GULF OF MEXICO...
THE GULF IS RATHER TRANQUIL THIS EVENING WITH A 1020 MB HIGH
SETTLING IN THE N CENTRAL GULF NEAR 28N91W. THIS PSN OF THE HIGH
HAS ALLOWED SFC WINDS TO RELAX OVER THE GULF INCLUDING THE  BAY
OF CAMPECHE AS WELL. IN THE MID AND UPPER LEVELS...THE PATTERN
REMAINS CONFLUENT BETWEEN AN UPPER HIGH OVER S MEXICO NEAR
21N102W AND AN UPPER LOW IN THE VICINITY OF HAVANA CUBA.
STRONGLY CONFLUENT FLOW AND ASSOCIATED SUBSIDENCE ALOFT IS
RESPONSIBLE FOR THE FAIR WEATHER. WHILE THE MAJORITY OF THE GULF
IS CURRENTLY CLEAR THERE IS SOME SIGNIFICANT CONVECTION
NEAR THE EDGES. SCATTERED STRONG CONVECTION IS EMERGING OFF THE
COAST BETWEEN THE FLORIDA PANHANDLE AND E-CENTRAL LOUISIANA.
WSR-88D DATA INDICATED THE STRONGEST ACTIVITY WAS CENTERED FROM
55 NM S OF MOBILE ALABAMA WWD THROUGH THE CHANDELEUR ISLANDS OFF
LOUISIANA TO NEAR GRAND ISLE. THE ACTIVITY WAS PRESSING SWD AT
20-25 KT. ADDITIONAL BUT WEAKER SCATTERED SHOWER ACTIVITY IS
PUSHING ACROSS THE UPPER FLORIDA KEYS AND THE STRAITS ASSOCIATED
WITH INSTABILITY NEAR THE UPPER LOW OVER CUBA.

CARIBBEAN SEA...
THE MOST ACTIVE WEATHER IS IN THE SW CARIB FROM THE N COAST OF
PANAMA/COSTA RICA TO 14N BETWEEN 77W-82W. THIS ACTIVITY IS
APPARENTLY SUPPORTED BY THE ITCZ AND ENHANCED IN A PRONOUNCED
UPPER DIFFLUENT ZONE. AN UPPER LOW WHICH WAS OVER FLORIDA
YESTERDAY HAS BEEN DRIFTING TO THE SW AND IS NOW CENTERED IN THE
VICINITY OF HAVANA CUBA. INSTABILITY NEAR THIS UPPER SYSTEM
AND OROGRAPHIC LIFT IS GENERATING SCATTERED SHOWER AND TSTM
ACTIVITY OVER CUBA. SURFACE OBSERVATIONS OVER THE WRN CARIBBEAN
INDICATED PRESSURES OF 1008-1010 MB AS FAR N AS THE CAYMAN
ISLANDS AND JAMAICA. THESE PRESSURES ARE ABOUT 2-3 MB BELOW
CLIMATOLOGICAL VALUES EVEN FACTORING IN DIURNAL OSCILLATIONS.
THE COMBINATION OF LOW PRESSURES...UPPER DIFFLUENCE SE OF THE
UPPER LOW AND THE APPROACHING TROPICAL WAVE ALONG 74W/75W
PRECLUDE THE POSSIBILITY OF MORE ORGANIZED CONVECTION IN THE
SAME AREA TOMORROW.

ATLANTIC OCEAN...
SHOWERS AND TSTMS OVER THE BAHAMAS ASSOCIATED WITH THE UPPER LOW
THAT IS DRIFTING TO THE SW OVER WRN CUBA HAVE DIMINISHED.
OTHERWISE...A WEAK SFC HIGH PRES RIDGE RULES THE WRN ATLC.
FARTHER NE...A LARGE STATIONARY VERTICALLY STACKED LOW PRES AREA
IS LOCATED NEAR 37N61W. THIS SYSTEM IS PROVIDING SOME SUPPORT
FOR A FRONTAL TROUGH WHICH ENTERS THE AREA NEAR 32N53W AND
EXTENDS SW TO 23N65W. ISOLATED SHOWERS ARE POSSIBLE WITHIN 120
NM E OF THIS BOUNDARY.

MUCH OF THE CENTRAL AND EASTERN ATLC DISCUSSION AREA IS UNDER
THE INFLUENCE OF SFC HIGH PRES ANCHORED BY A 1022 MB CENTER NEAR
27N33W RESULTING IN LIGHT TO MODERATE WINDS. WV IMAGERY SHOWS AN
UPPER TROUGH EXTENDING ALONG 32N40W TO 12N44W AND A SPRAWLING
RIDGE COVERING THE E ATLC WITH THE HIGH CENTERED OVER
MAURITANIA. THESE UPPER SYSTEMS ARE NOT PRODUCING MUCH MORE THAN
SCATTERED PATCHES OF CIRRUS.

$$
COBB




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