[Tropical] Tropical Weather Discussion

[EMWIN Server]

AXNT20 KNHC 171015 CCA
TWDAT

TROPICAL WEATHER DISCUSSION
NWS TPC/NATIONAL HURRICANE CENTER MIAMI FL
205 AM EDT THU AUG 17 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.

...SPECIAL FEATURE...
AN AREA OF LOW PRESSURE...LOCATED APPROXIMATELY 120 NM EAST OF
CHARLESTON SOUTH CAROLINA...HAS CHANGED LITTLE OVER THE PAST
SEVERAL HOURS WHILE DRIFTING WESTWARD.  SHOWER AND THUNDERSTORM
ACTIVITY REMAINS LIMITED AND MAXIMUM WINDS ARE ESTIMATED TO BE
NEAR 20 KT IN A FEW SPOTS.  WHILE THERE IS STILL SOME POTENTIAL
FOR THIS SYSTEM TO BECOME A TROPICAL DEPRESSION OVER THE NEXT 12
TO 24 HOURS...UPPER-LEVEL WINDS ARE BECOMING INCREASINGLY
UNFAVORABLE FOR DEVELOPMENT.

...TROPICAL WAVES...
AN EASTERN ATLANTIC OCEAN TROPICAL WAVE IS ALONG 30W SOUTH OF
21N MOVING WEST NEAR 10 KT.  A BROAD AREA OF CYCLONIC TURNING
AND INVERTED V PATTERN IS NOTED WNW OF THE CAPE VERDE ISLANDS. A
SMALL AREA OF SHOWERS AND TSTMS WAS NOTED AT 0000 UTC NEAR
16N31W...BUT THESE HAVE DIMINISHED OVER THE LAST FEW HOURS.
THERE IS NO SIGNIFICANT CONVECTION ASSOCIATED WITH THIS WAVE.

A CENTRAL ATLANTIC OCEAN TROPICAL WAVE IS ALONG 44W SOUTH OF
20N MOVING WEST NEAR 15 KT. BROAD CYCLONIC FLOW IN THE LOW CLOUD
FIELD IS SEEN ON SATELLITE IMAGERY...WITH SHOWER AND TSTM
ACTIVITY REMAINING MINIMAL. WINDS AT BUOY 41041 HAVE BEEN
VEERING FROM ENE TO E OVER THE LAST FEW HOURS...SUGGESTING THE
WAVE AXIS IS VERY CLOSE.

A CARIBBEAN SEA TROPICAL WAVE IS ALONG 75W SOUTH OF 20N MOVING
WEST NEAR 15 KT.  THERE ARE A FEW SHOWERS AND TSTMS NEAR THE NRN
PORTION OF THE AXIS NEAR ERN CUBA AND THE ADJACENT WATERS. THE
MOST SIGNIFICANT OF THESE IS A SMALL CLUSTER OF MODERATE
CONVECTION BETWEEN ERN CUBA AND THE SE BAHAMAS NEAR 22N75W. THE
CLUSTER OF MODERATE TO STRONG CONVECTION THAT AFFECTED
HISPANIOLA EARLIER IN THE EVENING HAS DIMINISHED. ANOTHER AREA
OF SCATTERED MODERATE CONVECTION LIES FROM 10N TO 13N BETWEEN
77W AND 84W...WITH ONE CLUSTER NOW AFFECTING COASTAL NICARAGUA.

...THE ITCZ...
ITCZ IS CENTERED ALONG 13N17W 13N30W 13N32W 10N43W 9N45W...AND
INLAND OVER SOUTH AMERICA TO NEAR 9N71W. THERE IS VERY LITTLE
SHOWER AND TSTM ACTIVITY WITHIN 250NM OF EITHER SIDE OF THE AXIS
FROM THE COAST OF AFRICA TO 30W. ISOLATED MODERATE CONVECTION
LIES MAINLY SOUTH OF THE AXIS FROM 6N TO 12N BETWEEN 33W AND
43W. ISOLATED SHOWERS AND TSTMS ALSO SEEN FROM 7N TO 10N BETWEEN
45W AND 55W.

...DISCUSSION...
THE GULF OF MEXICO...
THE CLUSTER OF MODERATE TO STRONG CONVECTION THAT WAS NOTED IN
THE NW GULF OFF THE COAST OF WRN LOUISIANA AT 0000 UTC HAS SINCE
DIMINISHED. SCATTERED SHOWERS AND TSTMS ARE STILL NOTED IN THE
WRN HALF OF THE GULF FROM 22N TO 30N BETWEEN 90W AND 96W. THESE
ARE ASSOCIATED WITH UPPER DIFFLUENCE BETWEEN AN UPPER LOW SEEN
SPINNING IN THE MIDDLE GULF NEAR 26N87W AND AN UPPER HIGH
CENTERED NEAR SHREVEPORT LOUISIANA...ALONG WITH LIFT S OF A
STATIONARY SURFACE FRONT JUST NORTH OF THE GULF COAST. A WEAK
1012MB SURFACE LOW IS NEAR 25N88W...WITH A SURFACE TROUGH
EXTENDING NNE THROUGH THIS LOW FROM THE YUCATAN PENINSULA TO
NEAR 29N86W. ONLY ISOLATED SHOWERS AND TSTMS ARE SEEN WITHIN
200NM OF ANY SIDE OF THIS LOW/TROUGH...WITH NO DEEP CONVECTION
NOTED. THESE SHOWERS ALONG WITH THE WEAK SFC LOW EXPECTED TO
DRIFT SLOWLY W OVER THE NEXT 24 HRS.

THE CARIBBEAN SEA...
A TROPICAL WAVE IS EXTENDING S THROUGH ERN CUBA AND JAMAICA. THE
MOST ACTIVE WEATHER IN THE CARIBBEAN TONIGHT LIES IN THE SW
PORTION OFF THE COAST OF NICARAGUA/COSTA RICA...AHEAD OF THE
TROPICAL WAVE. THIS IS ALSO LIKELY GETTING SUPPORT FROM THE ITCZ
AND THE UPPER HIGH OVER HONDURAS. ANOTHER AREA OF SCATTERED
MODERATE CONVECTION IS SURGING WESTWARD FROM THE SRN WINDWARD
ISLANDS INTO THE SE CARIBBEAN...FROM 11N TO 14N BETWEEN 61W AND
66W. MUCH OF THE REMAINDER OF THE CARIBBEAN IS UNDER THE
INFLUENCE OF MID TO UPPER LEVEL DRY AIR AND FAIR WEATHER. UPPER
WESTERLY FLOW IS HOVERING MUCH OF THE FAR NW CARIBBEAN BETWEEN
AN UPPER LOW JUST SW OF THE BAHAMAS...AND THE UPPER HIGH OVER
HONDURAS. MID TO UPPER LEVEL CYCLONIC FLOW DOMINATES THE ERN
CARIBBEAN AROUND THE ATLC UPPER LOW NEAR 22N61W. 10 TO 20 KT
TRADE FLOW DOMINATES MUCH OF THE CARIBBEAN AS THE SW PORTION OF
THE ATLC HIGH INTERACTS WITH A 1008MB LOW OVER NW VENEZUELA.
LIGHTER WINDS OBSERVED IN THE FAR NW CARIBBEAN WITH A WEAK
PRESSURE PATTERN IN TACT.

THE ATLANTIC OCEAN...
SHOWER AND TSTM ACTIVITY ASSOCIATED WITH THE 1012MB SURFACE LOW
OFF OF SOUTH CAROLINA REMAINS LIMITED. ANOTHER SURFACE LOW IS
SEEN SPINNING NEAR 30N61W...WITH A STATIONARY FRONT EXTENDING
THROUGH THIS LOW. ISOLATED SHOWERS AND TSTMS ARE NOTED WITHIN
150NM OF EITHER SIDE OF THE STATIONARY FRONT FROM 24N TO 32N
BETWEEN 40W AND 68W. THE MOST SIGNIFICANT OF THE WEATHER
ASSOCIATED WITH THIS FRONT IS A SMALL CLUSTER OF MODERATE
CONVECTION NEAR 29N54W. A DISTINCT UPPER LOW IS SEEN SPINNING
NEAR 21N60W. A FEW ISOLATED SHOWERS ARE SEEN NEAR THIS UPPER LOW
FROM 17N TO 25N BETWEEN 51W AND 62W. BROAD UPPER ANTICYCLONIC
FLOW DOMINATES MUCH OF THE REMAINDER OF THE CENTRAL AND ERN ATLC
FROM 7N TO 30N BETWEEN THE COAST OF AFRICA AND 50W. THIS REGION
IS ALSO DOMINATED BUT VAST FAIR WEATHER...AND WEAK SURFACE HIGH
PRESSURE.

$$
WILLIS


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