[Tropical] Tropical Weather Discussion

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AXNT20 KNHC 071818
TWDAT

TROPICAL WEATHER DISCUSSION
NWS TPC/NATIONAL HURRICANE CENTER MIAMI FL
205 PM EDT THU 07 OCT 2004

TROPICAL WEATHER DISCUSSION FOR NORTH AMERICA...CENTRAL
AMERICA...GULF OF MEXICO...CARIBBEAN SEA...NORTHEASTERN
SECTIONS OF SOUTH AMERICA...AND ATLC 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.

...TROPICAL WAVES...

NEW TROPICAL WAVE IS INTRODUCED ALONG 22W S OF 21N MOVING W AT
10 KT.  SATELLITE IMAGERY SHOWS A WELL DEFINED WAVE WITH
ISOLATED MODERATE CONVECTION FROM 6N-12N BETWEEN 19W-25W.

TROPICAL WAVE IS ALONG 34W S OF 13N MOVING W 10 KT.  A SURFACE
SWIRL IS NOTED ALONG THE ITCZ.  THE WAVE HAS A LOW AMPLITUDE AND
IS LOCATED UNDER THE BASE OF A MID/UPPER TROUGH WHICH IS
PRODUCING NW SHEAR OVER THE WAVE.  CONVECTION IS CONFINED TO THE
ITCZ WITH SCATTERED MODERATE TO ISOLATED STRONG FROM 8N-11N
BETWEEN 30W-38W.

TROPICAL WAVE IS ALONG 51W S OF 14N MOVING W 10-15 KT.  THIS IS
ANOTHER LOW AMPLITUDE WAVE THAT IS BEING OBSCURED ON SATELLITE
IMAGERY BY MIDDLE AND HIGH LEVEL CLOUDS.  SCATTERED MODERATE TO
ISOLATED STRONG CONVECTION IS FROM 10N-16N BETWEEN 47W-55W.

TROPICAL WAVE IS ALONG 60W S OF 18N DRIFTING WEST.  LOW LEVEL
CIRCULATION IS OBSERVED ALONG THE WAVE AXIS NEAR 16N.  MOST
CONVECTION IS E OF THE WAVE AXIS WITH SCATTERED MODERATE TO
ISOLATED STRONG FROM 13N-16N BETWEEN 58W-60W.  THIS WAVE
...TOGETHER WITH THE NEXT WAVE ALONG 51W... MAY BRING ABOUT A
SIGNIFICANT PERIOD OF LOCALIZED HEAVY RAIN FOR THE WINDWARD AND
LEEWARD ISLANDS.

...ITCZ...

ITCZ AXIS IS CENTERED ALONG 15N10W 9N22W 8N40W 14N60W 8N80W.
SCATTERED MODERATE TO ISOLATED STRONG CONVECTION IS FROM 8N-11N
BETWEEN 25W-38W...AND FROM 6N-10N BETWEEN 35W-42W.  SCATTERED
MODERATE CONVECTION IS FROM 8N-12N BETWEEN 43W-47W.

...DISCUSSION...

GULF OF MEXICO...
A 1010 MB LOW REMAINS OFF THE COAST OF MEXICO NEAR 22N96W.  A
SURFACE TROUGH EXTENDS N FROM THE CENTER TO THE TEXAS COAST NEAR
29N94W.  ANOTHER TROUGH EXTENDS S FROM THE CENTER TO S MEXICO
NEAR 17N94W.  SCATTERED MODERATE TO ISOLATED STRONG CONVECTION
IS FROM 20N-30N BETWEEN 91W-97W.  A WEAKENING STATIONARY FRONT
IS OVER S FLORIDA FROM 26N80W TO 27N87W.  SCATTERED SHOWERS ARE
WITHIN 60 NM OF THE FRONT.  IN THE UPPER LEVELS...A LARGE
ANTICYCLONIC CIRCULATION IS CENTERED OVER S MEXICO NEAR 17N94W.
A RIDGE AXIS EXTENDS N TO BEYOND 32N88W.  ANTICYCLONIC FLOW IS
WITHIN 600 NM OF THE RIDGE AXIS.  ABUNDANT MOISTURE COVERS THE
ENTIRE GULF OF MEXICO.

CARIBBEAN...
THE PRIMARY SURFACE FEATURE IN THE CARIBBEAN IS THE APPROACHING
TROPICAL WAVES AND THEIR ASSOCIATED CONVECTION.  IN THE UPPER
LEVELS...NW TO N FLOW DOMINATES THE W CARIBBEAN W OF 80W DUE TO
THE ANTICYCLONIC CIRCULATION CENTERED OVER S MEXICO NEAR
17N94W.  A LARGE CYCLONIC CIRCULATION REMAINS NEAR PUERTO RICO
AT 19N66W.  A TROUGH AXIS EXTENDS S TO N COLOMBIA NEAR 8N74W.
CYCLONIC FLOW IS FROM 8N-27N BETWEEN 57W-74W.  DRY SUBSIDENCE IS
OVER THE CARIBBEAN W OF THE TROUGH AXIS WHILE CONSIDERABLE
MOISTURE IS E OF THE TROUGH AXIS.

SUBTROPICAL ATLANTIC...
A STATIONARY FRONT IS OVER THE W ATLANTIC ALONG 32N64W 28N70W
26N77W WEAKENING TO FLORIDA NEAR 26N80W.  A SURFACE TROUGH NE OF
THE LEEWARD ISLANDS ALONG 30N55W 21N61W.  A 1023 MB HIGH IS OVER
THE CENTRAL ATLANTIC NEAR 35N47W.  IN THE UPPER LEVELS... A
TROUGH IS OVER THE W ATLANTIC N OF 24N BETWEEN 70W-80W.  A
TROUGH EXTENDS N FROM THE CYCLONIC CIRCULATION NEAR 19N66W TO
30N60W.  A LARGE RIDGE IS OVER THE CENTRAL ATLANTIC WITH AXIS
ALONG 10N55W TO WELL BEYOND 32N48W.  ANTICYCLONIC FLOW AND
CONSIDERABLE MOISTURE IS WITHIN 420 NM OF THE RIDGE AXIS.  A
CYCLONIC CIRCULATION IS OVER THE E ATLANTIC NEAR 24N32W.  A
TROUGH EXTENDS S TO NEAR 12N32W.  CYCLONIC FLOW AND SUBSIDENCE
IS WITHIN 600 NM OF THE TROUGH AXIS.

TROPICAL ATLANTIC...
AN UPPER LEVEL RIDGE IS OVER W AFRICA AND THE TROPICAL ATLANTIC
ALONG 16N1W 10N20W 7N40W. ANTICYCLONIC FLOW IS WITHIN 240 NM OF
THE AXIS. FURTHER W... THE WESTERLY UPPER LEVEL FLOW DUE TO THE
N/S RIDGE OVER THE CENTRAL ATLANTIC WILL MOST LIKELY IMPEDE
FURTHER TROPICAL DEVELOPMENT OF THE TROPICAL WAVES ALONG 51W
AND 60W.

$$
FORMOSA




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