[Tropical] Tropical Weather Discussion

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AXNT20 KNHC 090605
TWDAT

TROPICAL WEATHER DISCUSSION
NWS TPC/NATIONAL HURRICANE CENTER MIAMI FL
205 AM 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 0000 UTC SURFACE ANALYSIS AND SATELLITE IMAGERY
THROUGH 0515 UTC.

...TROPICAL WAVES...

A TROPICAL WAVE IS ALONG 34/35W S OF 11N MOVING W 10-15 KT. THIS
WAVE HAS LOST A GREAT DEAL OF ITS STRUCTURE AND CONVECTION SINCE
IT MOVED OFF THE AFRICAN COAST EARLY ON JUNE 5. THE PSN OF THE
WAVE FOLLOWS CONTINUITY AND IS PLACED ON THE UPSHEAR SIDE OF THE
ISOLATED SHOWERS/TSTMS W OF THE AXIS FROM 3N-6N BETWEEN 35W-40W.

A TROPICAL WAVE IS ALONG 58W S OF 14N MOVING W NEAR 15 KT. WAVE
PASSAGE WAS EVIDENT IN THE RAOBS AT CAYENNE FRENCH GUIANA
BETWEEN 07/1100 UTC AND 07/2300 UTC. SOME CYCLONIC TURNING NOTED
IN THE LOW CLOUD FIELD AROUND THE SRN WINDWARD ISLANDS...AND THE
WAVE MAY NEED TO BE NUDGED W A BIT TO ACCOUNT FOR THIS.
SCATTERED MODERATE CONVECTION IS MOSTLY E OF THE WINDWARD ISLANDS
FROM 12N-16N BETWEEN 56W-61W. HIGH CLOUDS OVER THE CONVECTION
ARE BEING STRETCHED EWD WITH UPPER WLY FLOW.

A TROPICAL WAVE ACROSS THE S CENTRAL CARIB IS ALONG 70W S OF 15N
MOVING W NEAR 15 KT. THIS WAVE IS DIFFICULT TO LOCATE AT THE
MOMENT ALTHOUGH PRESSURES IN THE VICINITY ARE A COUPLE OF MB
LOWER THAN THEY WERE LAST NIGHT. SCATTERED MODERATE CONVECTION
IS MOSTLY INLAND OVER COLOMBIA AND VENEZUELA. DRY/STABLE AIR
ALOFT IS PREVENTING MUCH SHOWER/TSTM ACTIVITY FROM OCCURRING
NEAR THE CARIBBEAN PORTION OF THE WAVE.

...THE ITCZ...

ITCZ AXIS IS CENTERED ALONG 6N10W 4N25W 6N34W 3N45W 7N56W.
NUMEROUS MODERATE. ISOLATED STRONG CONVECTION IS MOVING OFF THE
COAST OF AFRICA FROM 3N-12N BETWEEN 9W-17W. THIS ACTIVITY MAY BE
ASSOCIATED WITH THE NEXT TROPICAL WAVE ALTHOUGH SIMILAR
CONVECTION MOVED OFF AFRICA YESTERDAY AND HAS GREATLY DIMINISHED
SINCE. WILL WAIT AND SEE HOW THINGS EVOLVE OVER THE NEXT DAY OR
SO BEFORE ADDING ANOTHER WAVE. ELSEWHERE SCATTERED MODERATE
CONVECTION IS WITHIN 120NM N OF THE AXIS BETWEEN 26W-32W...AND N
OF THE AXIS FROM 8N-10N BETWEEN 52W-56W.

...DISCUSSION...

THE GULF OF MEXICO...
RETURN FLOW OVER THE GULF HAS RELAXED A BIT TONIGHT WITH A NEW
1019 MB HIGH PRES CENTER JUST S OF THE WRN FLORIDA PANHANDLE. A
RESIDUAL 4-7' E/SE SWELL REMAINS IN THE WRN GULF...WHICH WILL
ALSO RELAX OVER THE NEXT COUPLE OF DAYS AS THE WEAK HIGH DRIFTS
W. ALOFT...THE PATTERN IS CONFLUENT BETWEEN AN UPPER HIGH
CENTERED OVER S MEXICO NEAR 20N100W AND AN UPPER TROUGH
EXTENDING WSW THROUGH S FLORIDA AND INTO THE ERN GULF. THIS
PATTERN IS LEADING TO A DRY STABLE AIRMASS ACROSS MUCH OF THE
REGION AIDING IN THE WIDESPREAD FAIR WEATHER. DEBRIS MOISTURE IS
SPREADING INTO THE FAR WRN GULF DOWNSTREAM FROM CONVECTION OVER
MEXICO. SIMILAR UPPER MOISTURE IS NE OF A HAVANA TO NEW ORLEANS
LINE. THE CONVECTION OVER FLORIDA AND THE ERN GULF ASSOCIATED
WITH THE INSTABILITY AROUND THE UPPER TROUGH HAS DIMINISHED
GREATLY SINCE FRI.

THE CARIBBEAN SEA...
THE MOST ACTIVE WEATHER IN THE REGION REMAINS IN THE SW CARIB.
SATELLITE AND LIGHTNING DATA DEPICT SCATTERED TSTMS S OF 12N
BETWEEN COLOMBIA AND NICARAGUA. THIS ACTIVITY APPEARS MOSTLY
TIED TO THE ITCZ WITH SOME ENHANCEMENT FROM DIFFLUENCE ALOFT.
SCATTERED SHOWERS/ISOLATED TSTMS ARE ALSO IN A LOW LEVEL
CONFLUENT ZONE IN LEE OF JAMAICA FROM 15N-19N BETWEEN 78W-83W.
SIMILAR ACTIVITY IS BETWEEN VENEZUELA AND PUERTO RICO FROM
13N-16N BETWEEN 65W-69W. OUTSIDE OF THIS WEATHER AND THAT
DESCRIBED ABOVE WITH THE TROPICAL WAVES...MODERATE TO FRESH
TRADES AND FAIR WEATHER DOMINATE. MODERATE TRADES CONTINUE OVER
MUCH OF THE BASIN THROUGH SUN.

ATLANTIC OCEAN...
CONVECTION OVER THE SW NORTH ATLC ASSOCIATED WITH THE MID TO
UPPER TROUGH OVER THE AREA HAS DIMINISHED QUITE A BIT SINCE FRI
AFTERNOON. HOWEVER...SCATTERED TSTMS PERSIST BETWEEN CENTRAL
CUBA AND THE CENTRAL BAHAMAS S OF 25N BETWEEN 74W-80W.
OTHERWISE...WEAK SFC HIGH PRES RIDGE RULES WITH A 1018 MB CENTER
NEAR 30N72W. FARTHER NE...A LARGE VERTICALLY STACKED LOW PRES
AREA IS LOCATED NEAR 38N60W. THIS SYSTEM IS PROVIDING LIMITED
SUPPORT FOR A WEAKENING FRONTAL TROUGH WHICH EXTENDS FROM 32N55W
TO 25N62W. SCATTERED SHOWERS ARE WITHIN 120 NM E OF THIS
BOUNDARY...ALSO SUPPORTED BY UPPER DIFFLUENCE.

MUCH OF THE CENTRAL AND EASTERN ATLC DISCUSSION AREA IS UNDER
THE INFLUENCE OF WEAK SFC HIGH PRES RIDGING RESULTING IN LIGHT
WINDS. UPPER LOW WITH MEAN CENTER NEAR 30N42W IS BECOMING
ELONGATED AND APPEARS TO BE OPENING INTO A TROUGH. THIS FEATURE
IS GENERATING MOSTLY JUST PATCHES OF CIRRUS THOUGH ISOLATED
TSTMS POSSIBLE FROM 27N-30N BETWEEN 42W-45W. A S-SWLY JET
ORIGINATES NEAR THE BASE OF THE ASSOCIATED TROUGH NEAR 14N45W
AND CONTINUES NE TO 29N34W THEN TURNS EWD TO THE S OF A LARGE
DEEP LAYERED OCCLUDED LOW PRES SYSTEM E OF THE AZORES NEAR
40N21W.

$$
WILLIS




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