[Tropical] Tropical Weather Discussion

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AXNT20 KNHC 252358
TWDAT

TROPICAL WEATHER DISCUSSION
NWS TPC/NATIONAL HURRICANE CENTER MIAMI FL
805 PM EDT SAT JUN 25 2005

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

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

...TROPICAL WAVES...

EAST ATLANTIC TROPICAL WAVE IS ALONG 30W S OF 15N MOVING W 10-15
KT. THE WAVE IS EMBEDDED WITHIN A WEAK LOW-LEVEL FLOW REGIME AND
EASTERLY 30 KT WINDS AT 700 MB EMANATING OUT OF AFRICA ARE
GIVING THE WAVE A FORWARD TILT WITH HEIGHT. THE WAVE IS NOT
EASILY DEFINED IN SATELLITE IMAGERY...BUT UPPER AIR DATA FROM
SAL CAPE VERDE DID INDICATE A WAVE PASSAGE ABOUT 1-2 DAYS AGO.
THERE IS NO DEEP CONVECTION ASSOCIATED WITH THE WAVE.

CENTRAL ATLANTIC TROPICAL WAVE IS ALONG 42W/43W S OF 14N MOVING
W 15 KT. THIS WAVE IS ALSO NOT WELL-DEFINED IN SATELLITE IMAGERY
AND IS MARKED ONLY BY WIDELY SCATTERED SHOWERS/TSTMS TO THE E OF
THE AXIS...STRADDLING THE ITCZ.

TROPICAL WAVE NEAR THE WINDWARD ISLANDS IS ALONG 62W S OF 13N
MOVING W 15 KT. MUCH LIKE ITS TWO SUCCESSORS...THIS WAVE IS ALSO
VERY ILL-DEFINED IN SATELLITE IMAGERY. THE CAYENNE UPPER AIR
SOUNDING SHOWED A LOW-LEVEL PERTURBATION IN THE WIND FIELD BELOW
900 MB YESTERDAY...WHICH IS THE FEATURE WE HAVE BEEN TRACKING.
ONLY ISOLATED SHOWERS EXTEND FROM THE ORINOCO DELTA NW TO
TRINIDAD.

CENTRAL CARIBBEAN TROPICAL WAVE IS ALONG 77W/78W S OF 19N MOVING
W 10-15 KT. SLIGHT CURVATURE IN THE LOW-LEVEL CLOUD FIELD IS
OBSERVED EXTENDING FROM THE COLOMBIAN COAST NWD TO
JAMAICA.SCATTERED MODERATE TO ISOLATED STRONG CONVECTION IS NEAR
JAMAICA FROM 15N-20N BETWEEN 77W-82W.

WEST CARIBBEAN TROPICAL WAVE IS ALONG 86W/87W S OF 17N MOVING W
10-15 KT.  VISIBLE IMAGERY SHOWS LOW LEVEL CYCLONIC TURNING IN
THE GULF OF HONDURAS NEAR 16N87W.  PATCHES OF WIDELY SCATTERED
MODERATE CONVECTION IS OVER INLAND HONDURAS AND INLAND NICARAGUA
FROM 11N-16N BETWEEN 84W-89W.

...ITCZ...

ITCZ AXIS IS CENTERED ALONG 9N13W 7N17W 9N30W 8N42W 5N50W 5N60W.
SCATTERED MODERATE TO STRONG CONVECTION IS OFF THE COAST OF
AFRICA FROM 10N-13N BETWEEN 16W-20W.  ISOLATED MODERATE
CONVECTION IS FROM 5N-7N BETWEEN 15W-19W...AND FROM 7N-10N
BETWEEN 38W-42W.

...DISCUSSION...

GULF OF MEXICO...
A 1011 MB LOW IS LOCATED JUST N OF TAMPA FLORIDA.  A SURFACE
TROUGH EXTENDS S FROM THE LOW TO THE E GULF OF MEXICO NEAR
24N85W.  A TROUGH ALSO EXTENDS N FORM THE LOW TO THE W ATLANTIC
NEAR 32N77W.  A SMALL AREA OF SCATTERED MODERATE CONVECTION IS
NEAR COCOA FLORIDA WITHIN 15 NM RADIUS OF 28N81W.  FURTHER S...A
SURFACE TROUGH IS OVER W CUBA.  SCATTERED MODERATE CONVECTION IS
OVER THE STRAITS OF FLORIDA FROM 22N-24N BETWEEN 78W-82W.
ISOLATED MODERATE CONVECTION IS OVER THE BAY OF CAMPECHE FROM
17N-20N BETWEEN 93W-97W.  IN THE UPPER LEVELS... A CYCLONIC
CIRCULATION IS CENTERED OVER THE N GULF NEAR 30N88W.  CYCLONIC
FLOW AND SUBSIDENCE IS N OF 25N SIGNIFICANTLY SUPPRESSING
CONVECTION OVER THE N GULF TO INCLUDE TEXAS AND FLORIDA.  AN
ANTICYCLONIC CIRCULATION OVER THE GULF OF HONDURAS NEAR 17N87W
IS PRODUCING RIDGING OVER THE THE S GULF OF MEXICO S OF 25N.
PACIFIC MOISTURE AND OVERCAST HIGH CLOUDS COVERS THE AREA.
EXPECT A SURGE OF MOISTURE AND CONVECTION TO MOVE ACROSS
FLORIDA...THE SE GULF...AND THE YUCATAN PENINSULA BEHIND A
STRONG TROPICAL WAVE BEGINNING LATE SUN AND SPREADING TO THE W
GULF BY THU AND FRI.

CARIBBEAN...
SEE THE TROPICAL WAVE SECTION ABOVE.  IN ADDITION...SCATTERED
MODERATE TO STRONG CONVECTION IS OVER E CUBA FROM 20N-23N
BETWEEN 74W-79W.  SIMILAR CONVECTION IS OVER HISPANIOLA FROM
18N-20N BETWEEN 71W-73W...AND OVER LAKE MARACAIBO VENEZUELA FROM
8N-10N BETWEEN 70W-72W.  IN THE UPPER LEVELS...THE ANTICYCLONIC
CIRCULATION OVER THE GULF OF HONDURAS IS PRODUCING ANTICYCLONIC
FLOW AND SIGNIFICANT MOISTURE OVER THE W CARIBBEAN W OF 78W.  A
CYCLONIC CIRCULATION IS CENTERED OVER THE LEEWARD ISLANDS NEAR
15N61W PRODUCING CYCLONIC FLOW AND SUBSIDENCE E OF 78W ENHANCING
FAIR WEATHER E OF 70W.  EXPECT THIS AREA OF DRY AIR TO SPREAD
OVER MOST OF THE CARIBBEAN OVER THE NEXT COUPLE OF DAYS...WITH
THE NEXT ROUND OF SHOWERS/TSTMS EXPECTED TO MOVE OVER THE SRN
LEEWARD/WINDWARD ISLANDS BEGINNING LATE MON.

WEST ATLANTIC...
AN AIR FORCE C-130 RECONNAISSANCE AIRCRAFT INVESTIGATED AN AREA
OFF THE GEORGIA AND SOUTH CAROLINA COASTS THIS AFTERNOON AND
ONLY FOUND A 1012 MB SURFACE TROUGH WITH NO CLOSED CIRCULATION.
THE PREVIOUS SPECIAL FEATURE SECTION WAS THUS TERMINATED.
PRESENTLY WIDELY SCATTERED MODERATE CONVECTION IS FROM 28N-32N
BETWEEN 68W-74W. IN THE UPPER LEVELS...SLY FLOW AND SUBSIDENCE
IS OVER THE BAHAMAS AND FAR W ATLANTIC W OF 75W DUE TO THE
CYCLONIC CIRCULATION OVER THE N GULF OF MEXICO.  A RIDGE IS
FURTHER E... N OF 20N BETWEEN 65W-75W WITH SIGNIFICANT
MOISTURE.

CENTRAL/EAST ATLANTIC...
A 1026 MB HIGH IS NE OF BERMUDA AT 35N62W.  A SURFACE TROUGH IS
OVER THE CENTRAL ATLANTIC ALONG 32N49W 24N56W.  SCATTERED
SHOWERS ARE WITHIN 90 NM OF THE TROUGH.  THE E ATLANTIC HAS
MOSTLY SURFACE NE FLOW DUE TO A VERY LARGE 1033 MB HIGH CENTERED
NEAR 48N25W.  IN THE UPPER LEVELS...
A STRONG SHORTWAVE TROUGH IS
DIGGING SWD OVER THE CENTRAL ATLANTIC S OF 32N ALONG 32N56W
28N61W. A LARGE PATCH OF MID/UPPER LEVEL CLOUDS EXTENDS S OF THE
SHORTWAVE FROM 26N-30N BETWEEN 53W-63W...BUT VISIBLE IMAGERY
SUGGEST THAT PROBABLY ON ISOLATED SHOWERS ARE EMBEDDED WITHIN
THIS AREA. FARTHER E...A NEARLY STATIONARY UPPER TROUGH IS ALONG
32N45W 25N43W.  THE UPPER TROUGH EXTENDS SWWD INTO THE TROPICS
ALONG 20N47W TO NEAR TRINIDAD...AND A LARGE AREA OF DRY AIR IS
ROTATING WWD ON THE N SIDE OF THE TROUGH ADVECTING TOWARDS THE
LESSER ANTILLES. AN UPPER RIDGE LIES OVER THE E ATLC FROM ABOUT
THE COAST OF MAURITANIA ACROSS THE CAPE VERDES TO 11N40W...AND
THE SUBTROPICAL JET IS ALONG THE N PERIPHERY OF THE RIDGE
FEEDING INTO ANOTHER SHORTWAVE TROUGH THAT IS DROPPING DOWN TO
THE NW OF THE CANARY ISLANDS.

$$
FORMOSA




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