[Tropical] Tropical Weather Discussion

[EMWIN Server]

AXNT20 KNHC 170005
TWDAT

TROPICAL WEATHER DISCUSSION
NWS TPC/NATIONAL HURRICANE CENTER MIAMI FL
805 PM EDT SAT JUN 16 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...

ATLC TROPICAL WAVE IS ALONG 40W S OF 16N MOVING W 15-20 KT. WAVE
REMAINS FAIRLY EASY TO LOCATE WITH A BROAD INVERTED-V SIGNATURE.
CLUSTERS OF SCATTERED MODERATE CONVECTION ARE FROM 2N-10N
BETWEEN 35W-45W.

CARIBBEAN TROPICAL WAVE IS ALONG 71W S OF 14N MOVING W 10-15 KT.
THE WAVE REMAINS DIFFICULT TO LOCATE WITH NO SATELLITE SIGNATURE
NOTED. VERY DRY/STABLE MID TO UPPER AIR OVER THE AREA IS
SUPPRESSING CONVECTION IN THE VICINITY.

CARIBBEAN TROPICAL WAVE IS ALONG 81W S OF 15N MOVING W 10-15 KT.
OVERALL THIS WAVE IS ALSO DIFFICULT TO LOCATE WITH ITS PSN BASED
MAINLY ON CONTINUITY. THERE ARE SCATTERED SHOWERS/ISOLATED TSTMS
OFF THE COAST OF NICARAGUA FROM 11N-16N BETWEEN 79W-84W...BUT
THIS MAY BE ASSOCIATED WITH LOW LEVEL SPEED CONVERGENCE W OF THE
STRONG TRADES IN THE CENTRAL CARIB.

...THE ITCZ...

ITCZ AXIS IS CENTERED ALONG 10N14W 6N30W 7N41W 5N55W. NO DEEP
CONVECTION NOTED E OF 29W. SCATTERED MODERATE IS WITHIN 150 NM
EITHER SIDE OF THE AXIS BETWEEN 28W-35W. LOOKING BACK AT
SATELLITE HOVMOLLER DIAGRAMS...THIS MAY BE ASSOCIATED WITH A
QUICK MOVING LOW AMPLITUDE TROPICAL WAVE OR SURGE OF CONVECTION
THAT MOVED OFF AFRICA EARLY ON JUNE 15. HOWEVER...LITTLE
EVIDENCE IN THIS WAS NOTED IN THE AVAILABLE SOUNDING DATA OVER
AFRICA SO HAVE OPTED NOTE TO PLACE ANOTHER WAVE ON THE MAP AT
THIS POINT. ELSEWHERE...SCATTERED SHOWERS/ISOLATED TSTMS NOTED
WITHIN 220NM OF THE AXIS W OF 45W.

...DISCUSSION...

GULF OF MEXICO...
OVERALL THE SYNOPTIC PRES GRADIENT REMAINS LOOSE OVER THE
GULF...WITH WEAK SFC RIDGING OVER THE NRN WATERS AND TROUGHING
IN THE SE PORTION. THIS IS MOSTLY PRODUCING WINDS OF 15 KT OR
BELOW AND SEAS LESS THAN 4 FT ACROSS THE BASIN...EXCEPT POSSIBLY
HIGHER UNDER CONVECTION. THE HIGHLIGHT TONIGHT REMAINS THE
SIGNIFICANT MOISTURE AND SHOWER ACTIVITY OVER THE SE GULF MAINLY
SE OF THE TROUGH. AS OF 16/2100 UTC..THE ELONGATED SFC TROUGH
EXTENDS ENE FROM THE YUCATAN TO FAR SRN FLORIDA ALONG 21N88W
25N80W. AN IMPRESSIVE PULSE OF SHOWER/TSTM ACTIVITY MOVED
QUICKLY N FROM CUBA THROUGH THE FL KEYS OVER THE LAST COUPLE OF
HOURS...PROMPTING A SPECIAL MARINE WARNING FROM WFO KEY WEST
EARLIER THIS EVENING. THIS ACTIVITY ALSO BEING SUPPORTED BY
UPPER DIFFLUENCE BETWEEN AN UPPER RIDGE EXTENDING E ALONG 22/23N
AND TROUGHING NE OF THE AREA. SCATTERED SHOWERS/TSTMS ALSO NEAR
THE E TEXAS/LOUISIANA COAST...MAINLY N OF 28N BETWEEN 93W-96W.
THIS IS ASSOCIATED WITH INSTABILITY AHEAD OF THE UPPER LOW OVER
TEXAS AND THE WARM/MOIST LOW LEVEL INFLOW FROM THE S.  LOOK FOR
SCATTERED SHOWERS/ISOLD TSTMS ASSOCIATED WITH THE SFC TROUGH TO
PUSH N/NW THROUGH THE E AND MIDDLE GULF OVER THE NEXT DAY OR SO.

CARIBBEAN SEA...
SIGNIFICANT MOISTURE WITH SCATTERED SHOWERS/ISOLATED TSTMS ARE
OVER THE NW CARIBBEAN AND CUBA...NOW MAINLY N OF 18N W OF 78W.
THIS ACTIVITY IS ASSOCIATED THE TROUGH MENTIONED IN THE GULF
SECTION. THE OTHER STORY...BESIDES FOR THE TROPICAL WAVES...IS
THE CONTINUED STRONG TRADES ESPECIALLY BETWEEN 68W-80W. FRESH TO
STRONG TRADES LOOK TO CONTINUE IN THIS VICINITY THROUGH SUN. A
FEW SHOWERS AND TSTMS ARE NOTED N OF THE ABC ISLANDS FROM
13N-16N BETWEEN 66W-69W...LIKELY AIDED BY THE UPPER LOW OVER THE
LESSER ANTILLES REGION. OTHERWISE...VERY DRY/STABLE MID TO UPPER
AIR AND FAIR WEATHER RULE.

ATLANTIC OCEAN...
NUMEROUS SHOWERS/SCATTERED TSTMS ARE AFFECTING THE
BAHAMAS...SOUTH FLORIDA...AND ADJACENT WATERS TONIGHT ASSOCIATED
WITH THE AFOREMENTIONED ELONGATED TROUGH OF LOW PRESSURE
EXTENDING ENE FROM THE YUCATAN PENINSULA. A 1015 MB LOW WAS
ADDED TO THE 1800 UTC MAP NEAR THE NORTHWESTERN BAHAMAS PER THE
CYCLONIC CIRCULATION NOTED IN BOTH SATELLITE IMAGERY AND SFC
OBSERVATIONS. HOWEVER...UPPER-LEVEL WINDS ARE NOT
FAVORABLE FOR THIS LOW TO DEVELOP INTO A TROPICAL CYCLONE AS IT
MOVES EAST-NORTHEASTWARD INTO THE ATLANTIC. A PLUME OF TROPICAL
MOISTURE WITH POSSIBLE SHOWERS IS BEING STRETCHED NE WITH UPPER
SW FLOW...WITHIN 150NM EITHER SIDE OF A ELEUTHERA TO BERMUDA
LINE. DISTINCT UPPER DIFFLUENCE NOTED OVER THIS REGION BETWEEN
THE TROUGHING OVER THE EAST COAST AND RIDGING EXTENDING NE FROM
ERN CUBA. OVERALL THE REMAINDER OF THE DISCUSSION AREA IS
TRANQUIL...WITH A 1025 MB SFC HIGH NEAR 27N60W AND A 1024 MB
CENTER NEAR 27N45W. A DISSIPATING COLD FRONT IS OVER THE FAR NE
PORTION OF THE AREA ALONG 31N20W 28N30W...ASSOCIATED WITH A DEEP
LAYER LOW W OF NRN PORTUGAL. NO SIGNIFICANT CONVECTION IS IN
THIS VICINITY.

$$
WILLIS


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