[Tropical] Tropical Weather Discussion

[EMWIN Server]

AXNT20 KNHC 160603
TWDAT

TROPICAL WEATHER DISCUSSION
NWS TPC/NATIONAL HURRICANE CENTER MIAMI FL
205 AM EDT WED AUG 16 2006

TROPICAL WEATHER DISCUSSION FOR NORTH AMERICA...CENTRAL
AMERICA...THE GULF OF MEXICO...THE CARIBBEAN SEA...NORTHEASTERN
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...WEATHER OBSERVATIONS...RADAR...
AND METEOROLOGICAL ANALYSIS.

BASED ON 0000 UTC SURFACE ANALYSIS AND SATELLITE IMAGERY THROUGH
0545 UTC.

...TROPICAL WAVES...
AN ATLANTIC OCEAN 1012 MB SURFACE LOW PRESSURE CENTER IS SW OF
THE CAPE VERDE ISLANDS NEAR 13N27W MOVING WEST 10 TO 15 KT.
CONVECTION NEAR THIS LOW IS LIMITED WITH ONLY ISOLATED SHOWERS
AND TSTMS NOTED IN THE VICINITY.

AN ATLANTIC OCEAN TROPICAL WAVE IS ALONG 39W SOUTH OF 21N MOVING
WEST NEAR 10 KT.  THIS WAVE CONTINUES TO EXHIBIT A CLASSIC
INVERTED V PATTERN BUT CONVECTION REMAINS LIMITED N OF THE ITCZ
AXIS NEAR 10N. SCATTERED MODERATE CONVECTION IS NOTED SOUTH OF
THE ITCZ FROM 4N-8N BETWEEN 37W AND 42W.

A CARIBBEAN SEA TROPICAL WAVE EXTENDING S THROUGH THE DOMINICAN
REPUBLIC IS ALONG 70W SOUTH OF 20N MOVING WEST 15 KT. CYCLONIC
CURVATURE IS STILL EVIDENT ABOUT THE WAVE AXIS THOUGH THIS WAVE
IS NOT NEARLY AS DEFINED AS IT USED TO BE. SCATTERED MODERATE
CONVECTION IS AFFECTING ERN HISPANIOLA AND THE ADJACENT WATERS.
MUCH OF THE REMAINDER OF THE CARIBBEAN PORTION OF THIS WAVE IS
SHOWER FREE UNDER THE INFLUENCE OF AN UPPER HIGH AND DRY
AIR...FROM 11N TO 17N WITHIN 200NM OF EITHER SIDE OF THE WAVE.

...THE ITCZ...
ITCZ IS CENTERED ALONG 16N16W 13N35W 10N38W 10N41W AND INLAND
OVER SOUTH AMERICA TO NEAR 9N69W. VERY LITTLE SHOWER/TSTM
ACTIVITY IS NOW NOTED NEAR THE ITCZ OFF THE COAST OF AFRICA.
CLUSTERS OF SCATTERED MODERATE CONVECTION LIE FROM 10N TO 12N
BETWEEN 28W AND 32W...AND FROM 4N TO 9N BETWEEN 35W AND 50W.
ISOLATED SHOWER AND TSTM ACTIVITY IS NOTED ELSEWHERE WITHIN
200NM OF EITHER SIDE OF THE AXIS.

...DISCUSSION...
THE GULF OF MEXICO...
THE SURFACE LOW CENTER THAT WAS PREVIOUSLY IN THE NE GULF OF
MEXICO IS NO LONGER EVIDENT...THOUGH A TROUGH STILL EXISTS FROM
26N85W TO 29N87W. SHOWERS AND TSTMS ASSOCIATED WITH THIS FEATURE
HAVE DIMINISHED THIS EVENING...THOUGH SOME SLOW DEVELOPMENT IS
POSSIBLE OVER THE NEXT DAY OR SO. THE MAIN FEATURE NOW BEGINNING
TO AFFECT THE GULF IS A LARGE MCS MOVING SOUTH FROM THE WRN
FLORIDA PANHANDLE AND CENTRAL GULF COAST STATES. DOPPLER RADAR
SHOWS STRONG SHOWERS AND TSTMS PUSHING INTO THE NRN GULF FROM
29N-30N BETWEEN CAPE SAN BLAS AND SE LOUISIANA. ISOLATED SHOWERS
AND TSTMS ARE ALSO NOTED IN THE FAR ERN GULF JUST OFF THE W
COAST OF FLORIDA...ASSOCIATED WITH INSTABILITY AROUND THE UPPER
LOW SPINNING OVER CENTRAL FLORIDA. 16/0000 UTC GFS SEEMS TO HAVE
THIS INITIALIZED WELL...SHOWING A DISTINCT REGION OF 500MB
POSITIVE VORTICITY ADVECTION IN THE REGION JUST OFFSHORE CEDAR
KEY THROUGH TAMPA...AND SUGGESTS THIS REGION WILL DRIFT SLOWLY W
TODAY. THE W/SW GULF IS FAIRLY QUIET TONIGHT.

THE CARIBBEAN SEA...
A TROPICAL WAVE IS MOVING THROUGH HISPANIOLA AS DISCUSSED ABOVE.
OVERALL THE CARIBBEAN IS FAIRLY INACTIVE ASIDE FROM A COUPLE OF
SMALL CLUSTERS OF MODERATE CONVECTION IN THE SW GULF OFF THE
COAST OF PANAMA AND COSTA RICA...JUST NORTH OF THE ITCZ. MID TO
UPPER LEVEL ANTICYCLONE CENTERED JUST SOUTH OF HISPANIOLA NEAR
15N70W IS AFFECTING MUCH OF THE CENTRAL CARIBBEAN. A WEAK UPPER
TROUGH IS OVER THE NW CARIBBEAN...WHILE THE ATLC UPPER LOW ENE
OF THE LEEWARD ISLANDS IS PRODUCING UPPER CYCLONIC FLOW OVER THE
NE AND E CARIBBEAN. COLOMBIAN LOW CONTINUES TO INTERACT WITH A
FAIRLY WEAK ATLC SFC RIDGE...WITH 15 TO 20KT TRADE FLOW
DOMINATING MUCH OF THE CARIBBEAN...THOUGH A WEAKER GRADIENT AND
LIGHTER WINDS ARE OBSERVED FAR NW PORTION.

THE ATLANTIC OCEAN...
A SURFACE LOW PRESSURE SYSTEM IS LOCATED A FEW HUNDRED MILES
SOUTHEAST OF THE SOUTH AND NORTH CAROLINA COASTS.  WHILE THE
ASSOCIATED SHOWER AND THUNDERSTORM ACTIVITY REMAINS
MINIMAL...THIS SYSTEM STILL HAS SOME POTENTIAL FOR TROPICAL
CYCLONE FORMATION OVER THE NEXT DAY OR SO AS IT MOVES SLOWLY
NORTHWARD.  AN AIR FORCE RESERVE RECONNAISSANCE AIRCRAFT IS
SCHEDULED TO INVESTIGATE THE SYSTEM ON WEDNESDAY...IF NECESSARY.
A SURFACE TROUGH EXTENDS THROUGH THE FLORIDA KEYS AND NRN
BAHAMAS AND NE THROUGH THE LOW OFF THE CAROLINAS. A SMALL
CLUSTER OF MODERATE CONVECTION ASSOCIATED WITH THIS TROUGH IS
NOTED NE OF THE ABACOS NEAR 28N77W. A DISTINCT UPPER LOW IS SEEN
SPINNING JUST INLAND FROM CAPE CANAVERAL...EXTENDING E INTO THE
WRN ATLC. UPPER RIDGING IS EXTENDING N FROM HISPANIOLA WHILE AN
UPPER LOW IS ENE OF THE LEEWARD ISLANDS NEAR 20N57W. A FEW
ISOLATED SHOWERS NEAR THIS UPPER LOW ARE SEEN FROM 18N-24N
BETWEEN 53W-59W. ELSEWHERE IN THE WRN ATLC...A WEAK SURFACE LOW
REMAINS ALONG AN OLD FRONTAL BOUNDARY NEAR 28N60W. ISOLATED
SHOWER AND TSTM ACTIVITY PERSIST ALONG THIS BOUNDARY FROM
26N-32N BETWEEN 53W-71W. BROAD UPPER RIDGING CONTINUES TO
DOMINATE MUCH OF THE ERN ATLC...WITH THE RIDGE AXIS EXTENDING W
FROM AFRICA ALONG 20N OUT TO 35W. FAIR WEATHER ALONG WITH WEAK
SURFACE HIGH PRESSURE DOMINATES MUCH OF THIS AREA FROM 15N-30N
BETWEEN AFRICA AND 55W.

$$
WILLIS



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