[Tropical] Tropical Weather Discussion

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AXNT20 KNHC 041744
TWDAT

TROPICAL WEATHER DISCUSSION
NWS TPC/NATIONAL HURRICANE CENTER MIAMI FL
205 PM EDT MON SEP 04 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 1200 UTC SURFACE ANALYSIS AND SATELLITE IMAGERY
THROUGH 1715 UTC.

...SPECIAL FEATURE...
THE CENTER OF TROPICAL DEPRESSION SIX AT 04/1200 UTC IS CENTERED
NEAR 16.3N 42.7W IN THE TROPICAL ATLANTIC. IT IS MOVING
NORTHWEST AT 10 KT. THE ESTIMATED MINIMUM CENTRAL PRESSURE IS
1005 MB. THE MAXIMUM SUSTAINED WIND SPEED IS 30 KT WITH GUSTS TO
40 KT. PLEASE READ THE LATEST NHC FORECAST/ADVISORY UNDER
AWIPS/WMO HEADERS MIATCMAT1/WTNT21 KNHC AND THE PUBLIC ADVISORY
UNDER MIATCPAT1/WTNT31 KNHC FOR MORE DETAILS. T.D. SIX IS SLOWLY
ORGANIZED WITH CURVED BANDS BECOMING BETTER DEFINED TO THE N AND
E OF THE CENTER. SHOWERS AND TSTMS ARE MOST ORGANIZED IN THESE
BANDS WITHIN 200 NM OF THE CENTER. A LARGE MID-UPPER LEVEL
TROUGH TO THE NW OF THE DEPRESSION HAS BEEN PRODUCING MODERATE
SWLY SHEAR LIKELY ONLY ALLOWING FOR SLOW INTENSIFICATION OVER
THE NEXT COUPLE OF DAYS AS THE SYSTEM MOVES NW INTO THIS
WEAKNESS. THIS SYSTEM IS FORECAST TO BECOME A TROPICAL STORM
WITHIN THE NEXT 24 HOURS.

...TROPICAL WAVES...
AN E ATLC TROPICAL WAVE IS ALONG 28W FROM 8N-20N MOVING W NEAR
10 KT OVER THE PAST 24 HOURS. THIS SYSTEM REMAINS WELL-DEFINED
WITH A LARGE CIRCULATION ANALYZED AS A 1010 MB LOW ALONG THE
WAVE NEAR 15N. SCATTERED SHOWERS AND TSTMS ARE MOST ORGANIZED IN
A BROKEN CURVED BAND FEATURE WRAPPING AROUND THE SFC
LOW...NAMELY FROM 10N-19N BETWEEN 26W-34W. THIS BROAD AREA IS
BEING MONITORED AS THERE IS SOME POTENTIAL FOR DEVELOPMENT IN
THE NEXT DAY OR TWO.

A 1008 MB SURFACE LOW IS ANALYZED NEAR 13N47W. THIS LOW PRES
AREA IS LOCATED ONLY A FEW HUNDRED NM SE OF T.D. SIX WHICH HAS
SHEARED CONVECTION TO THE S OF THE LOW-LEVEL CENTER. THIS
FEATURE WILL LIKELY CONTINUE TO BE SHEARED DUE TO ITS CLOSE
PROXIMITY OF T.D SIX AND ITS EXPANDING CIRCULATION.
SCATTERED SHOWERS EXIST FROM 10N-14N BETWEEN 45W-50W.

A TROPICAL WAVE HAS BEEN RELOCATED ALONG 55W FROM 8N-21N. THIS
RELOCATION IS BASED ON SATELLITE IMAGERY AND SFC OBSERVATIONS
WHICH SHOW A CLEAR LOW CLOUD INVERTED V WAVE STRUCTURE. ALL OF
THE ASSOCIATED CONVECTION HAS BEEN SHEARED WELL AHEAD OF THE
WAVE AXIS FROM 12N-18N BETWEEN 60W-66W. THIS POORLY ORGANIZED
WAVE WILL CONTINUE TO MOVE TO THE W NEAR 10 KT OR SO.

A CARIBBEAN SEA TROPICAL WAVE IS ALONG 73W SOUTH OF 20N MOVING
WEST NEAR 10 KT. A SHARP UPPER TROUGH IN THE AREA IS MASKING THE
LOW-LEVEL SIGNATURE...HOWEVER SOME LOW-MID LEVEL CYCLONIC
TURNING IS STILL NOTICEABLE ON VIS IMAGES AND SFC OBSERVATIONS.
THE INTERACTION OF THIS WAVE AND THE UPPER TROUGH IS TRIGGERING
SCATTERED SHOWERS AND TSTMS FROM 12N-17N BETWEEN 73W-80W.

...THE ITCZ...
ITCZ AXIS IS CENTERED ALONG 14N16W 16N27W 13N35W 12N53W 12N58W
11N62W THEN ALONG THE N COAST OF S AMERICA AND ACROSS PANAMA.
BESIDES FOR THE CONVECTION ASSOCIATED WITH T.D. SIX AND THE
TROPICAL WAVES...SCATTERED MODERATE CONVECTION IS MOVING OFF THE
AFRICAN COAST E OF 16W FROM 4N-11N. CLUSTERS OF SCATTERED
MODERATE CONVECTION IS OVER W COLOMBIA MOVING INTO THE EPAC.

...DISCUSSION...

THE GULF OF MEXICO...
MID-UPPER LEVEL TROUGHING LIES ACROSS THE E GULF WITH A PAIR OF
UPPER LOWS EMBEDDED. ONE UPPER LOW CENTER IS NEAR 26N87W AND
THE OTHER IS NE OF THE BAHAMAS IN THE W ATLC. AN UPPER HIGH IS
ANCHORED OVER NW MEXICO WITH RIDGING EXTENDING ACROSS THE S U.S.
AND N GULF OUT TO 88W. ANOTHER WEAK UPPER HIGH IS CENTERED IN
THE BAY OF CAMPECHE. THIS PATTERN IS PRODUCING A CONSIDERABLE
AMOUNT OF MOISTURE SE OF A LINE ALONG 24N98W 25N87W 30N84W. THE
DEEPEST MOISTURE IS IN THE SE GULF WHERE SCATTERED SHOWERS AND
TSTMS ARE INCREASING IN COVERAGE S OF 26N E OF 86W ACROSS S
FLORIDA. THIS MOISTURE IS ENHANCED BY A SFC TROUGH OR THE N
PORTION OF A CARIBBEAN TROPICAL WAVE THAT MAY HAVE BROKE OFF A
COUPLE OF DAYS AGO. A STATIONARY FRONT EXTENDS FROM S MS TO
28N91W TO THE TEXAS COAST NEAR 29N95W. A SFC TROUGH LIES ABOUT
100 NM SE OF THE FRONT FROM THE FL PANHANDLE SW ALONG 28N89W
26N96W. A LINE OF CLOUDS AND SCATTERED SHOWERS ARE WITHIN 60 NM
EITHER SIDE OF THE SFC BOUNDARY. OVERALL...DEEP MOISTURE IS
SOMEWHAT LIMITED IN THE NW GULF AS MODERATE SUBSIDENCE COVERS
THE MAJORITY OF THE REGION N OF 25N W OF 88W. IN FACT..BEHIND
THE FRONTAL BOUNDARY DEWPOINT TEMPS ARE IN THE HIGH 50'S AND LOW
60'S ACROSS THE CENTRAL U.S. GULF COAST. SCATTERED SHOWERS AND
TSTMS ARE ALSO IN THE BAY OF CAMPECHE. THE MOIST PATTERN IN THE
E GULF IS EXPECTED TO PERSIST TONIGHT AND TOMORROW.
THEREAFTER... GFS TAKES THE BULK OF THE MOISTURE TO THE NE OF
THE AREA.

THE CARIBBEAN SEA...
A SHARP UPPER TROUGH COVERS THE W CARIBBEAN WITH THE AXIS
EXTENDING FROM THE SE BAHAMAS ACROSS THE WINDWARD PASSAGE TO
NEAR NICARAGUA. A FAIR AMOUNT OF MOISTURE IS ON THE W SIDE OF
THE TROUGH ACROSS THE NW CARIBBEAN WITH SCATTERED SHOWERS AND
TSTMS ARE FOUND N OF 17N W OF 80W. UPPER DIFFLUENCE NEAR THE
BASE OF THE TROUGH AND ON THE SE SIDE INTERACTING WITH A
TROPICAL WAVE ALONG 73W IS PRODUCING SIMILAR ACTIVITY BETWEEN
72W-77W MAINLY S OF 17N. ANOTHER AREA OF UNSETTLED WEATHER IS IN
THE E CARIBBEAN AHEAD OF A TROPICAL WAVE ALONG 55W. SCATTERED
SHOWERS AND TSTMS EXIST FROM 12N-18N BETWEEN 60W-66W. A NARROW
AREA OF DRY STABLE AIR LIES BETWEEN 66W AND 72W GENERATED BY AN
UPPER HIGH OVER PUERTO RICO. TRADE WINDS ARE GENERALLY IN THE
15-20 KT RANGE E OF 80W...LIGHTER WINDS W OF THERE. GFS HAS THE
OVERALL MOISTURE PATTERN INITIALIZED WELL AND INDICATES THAT THE
MOST ORGANIZED TROPICAL MOISTURE WILL REMAIN IN THE E CARIBBEAN
TOMORROW.

THE ATLANTIC OCEAN...
AN UPPER TROUGH COVERS THE ATLC AND MUCH OF THE CARIBBEAN W OF
72W. CONSIDERABLE MOISTURE LIES UNDER THE INFLUENCE OF THE
TROUGH...HOWEVER THE MOST ORGANIZED PRECIP IS IN THE W BAHAMAS
AND NEAR THE SE FLORIDA COAST WHERE UPPER DIFFLUENCE IS
STRONGEST S OF AN UPPER LOW CENTERED NEAR 29N75W. AN UPPER LEVEL
HIGH IS CENTERED TO THE NE OF THE TROUGH NEAR 32N67W. ANOTHER
UPPER HIGH IS CENTERED TO THE S OF THE AREA NEAR PUERTO RICO.
ESSENTIALLY...A NARROW AREA OF UPPER RIDGING EXISTS BETWEEN
59W-72W. A DEEP LAYER TROUGH COVERS THE REGION BETWEEN 37W AND
55W N OF 23N. MODERATE SWLY SHEAR ASSOCIATED WITH THIS TROUGH IS
AFFECTING T.D. SIX AND WILL LIKELY LIMIT ANY RAPID
INTENSIFICATION OVER THE NEXT COUPLE OF DAYS. AN ASSOCIATED SFC
FRONT ENTERS THE AREA NEAR 32N37W AND EXTENDS SW ALONG 29N39W
25N50W THEN STATIONARY TO 24N63W THEN NORTHWARD AS DISSIPATING
STATIONARY FRONT TO 32N64W. SCATTERED SHOWERS ARE WITHIN 180 NM
OF THE BOUNDARY. DUE TO THE SLOW MOVEMENT OF THE
BOUNDARY...BERMUDA HAS RECEIVED OVER 2 INCHES OF RAIN OVER THE
LAST 24 HOURS. FARTHER EAST...A BROAD MID-UPPER LEVEL RIDGE
COVERS THE REMAINDER OF THE REGION WITH THE MAIN HIGH CENTER
NEAR 22N27W. AT THE SFC...RIDGING LIES TO THE E OF THE FRONT
ANCHORED FROM A 1023 MB HIGH 350-400 NM E OF THE AZORES. WEAKER
RIDGING EXISTS IN THE CENTRAL AND W ATLC DUE TO THE FRONTAL
BOUNDARY DRAPED ACROSS THE AREA.

$$
CANGIALOSI


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