[Tropical] Tropical Weather Discussion

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AXNT20 KNHC 052358
TWDAT

TROPICAL WEATHER DISCUSSION
NWS TPC/NATIONAL HURRICANE CENTER MIAMI FL
805 PM EDT TUE 05 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 1800 UTC SURFACE ANALYSIS AND SATELLITE IMAGERY THROUGH
2315 UTC.

...TROPICAL WAVES...

TROPICAL WAVE IS INTRODUCED ALONG 38W S OF 16N MOVING WEST NEAR
15 KT.  THE WAVE IS PRODUCING ENHANCED ITCZ CONVECTION WITH
SCATTERED MODERATE/ISOLATED STRONG ACTIVITY FROM 6N-14N BETWEEN
30W-40W.

TROPICAL WAVE IS LOCATED ABOUT 250 NM E OF BARBADOS ALONG 55W S
OF 20N MOVING W 10 KT. THE WAVE IS INTERACTING WITH A MID-UPPER
LEVEL TROUGH WHICH IS PRODUCING A BROAD AREA OF CONVECTION AND
SEVERAL AREAS OF LOW-LEVEL ROTATION.  THE CURRENT POSITION IS
BASED ON CONTINUITY AND THE APPEARANCE OF A PERSISTENT
CIRCULATION NEAR 14N55W.  SCATTERED MODERATE/ISOLATED STRONG
CONVECTION LOCATED E OF AXIS FROM 13N-18N BETWEEN 49W-55W.
CONDITIONS ARE EXPECTED TO REMAIN UNFAVORABLE FOR SIGNIFICANT
DEVELOPMENT.

W CARIBBEAN TROPICAL WAVE IS ALONG 85W S OF 20N MOVING W 15-20
KT.  THE WAVE IS PRODUCING AN AREA OF SCATTERED MODERATE
CONVECTION FROM 11N-16N BETWEEN 81W-85W.  A SECOND AREA OF
SCATTERED MODERATE CONVECTION IS LOCATED FURTHER W OVER
BELIZE...N GUATEMALA...AND THE YUCATAN PENINSULA FROM 16N-20N
BETWEEN 87W-92W.

...ITCZ...

ITCZ AXIS IS CENTERED ALONG 11N10W 8N25W 11N38W 8N50W 10N65W
6N80W.  SCATTERED MODERATE CONVECTION MOVING OFF THE COAST OF
AFRICA FROM 5N-12N BETWEEN 8W-20W.

...DISCUSSION...

GULF OF MEXICO...
BUILDING MID TO UPPER LEVEL RIDGE IS LOCATED OVER THE GLFMEX
AHEAD OF A DEVELOPING TROUGH OVER THE SW UNITED STATES AND
INTERIOR MEXICO.  THIS PATTERN IS GENERATING UPPER LEVEL
DIVERGENT FLOW OVER THE W GLFMEX AND PRODUCING SCATTERED TO
NUMEROUS SHOWERS/THUNDERSTORMS NEAR A LOW LEVEL TROUGH
PRIMARILY FROM 21N-26N BETWEEN 90W-97W. ASSOCIATED MOISTURE IS
CURRENTLY SURGING NWD AND IS EXPECTED TO POOL ALONG A STATIONARY
FRONT WHICH CURRENTLY EXTENDS FROM N FLORIDA TO S TEXAS DURING
THE NEXT 24 -36 HOURS.  AT THE SAME TIME...THE UPPER TROUGH OVER
MEXICO WILL BECOME INCREASINGLY AMPLIFIED WITH AN UPPER JET
FORMING OVER THE S UNITED STATES.  THIS WILL SET THE STAGE FOR A
RATHER UNSETTLED/STORMY PATTERN OVER THE NW GLFMEX AND TEXAS
COAST WED AND THU. ELSEWHERE OVER THE GLFMEX...DRY TRANQUIL
CONDITIONS PREVAIL E OF 90W WITH THE ONLY CLOUDS OF NOTE BEING
HIGH CIRRUS FANNING EWD OVER THE AREA.

CARIBBEAN...
THERE HAS BEEN LITTLE CHANGE OVER THE CARIBBEAN DURING THE LAST
24 HOURS.  DIVERGENT UPPER LEVEL FLOW AND DEEP TROPICAL MOISTURE
ON THE EQUATORWARD SIDE OF A SHARP RIDGE EXTENDING FROM COLOMBIA
TO THE YUCATAN PENINSULA CONTINUES TO PRODUCE ENHANCED
CONVECTIVE ACTIVITY OVER CENTRAL AMERICA.  WHILE THIS ACTIVITY
HAS BEEN PRIMARILY FOCUSED ALONG THE CARIBBEAN SIDE OF CENTRAL
AMERICA... THE OVERALL MOISTURE AXIS IS BEGINNING TO SHIFT
SLOWLY WESTWARD AND THIS TREND SHOULD CONTINUE DURING THE NEXT
DAY OR SO.  OVER THE CENTRAL CARIBBEAN...LARGE MIDDLE TO UPPER
LEVEL LOW JUST N OF PUERTO RICO EXTENDS A TROUGH SWD TO THE
COAST OF COLOMBIA NEAR 11N74W.  STRONG SUBSIDENCE ON THE
BACK/WEST SIDE OF THE TROUGH IS SUPPRESSING CONVECTIVE ACTIVITY
OVER MUCH OF THE GREATER ANTILLES AND THE CENTRAL CARIBBEAN.
EAST OF THE TROUGH...DIVERGENT FLOW IS SUPPORTING WIDELY
SCATTERED SHOWERS/THUNDERSTORMS OVER THE LESSER ANTILLES.
NUMERICAL GUIDANCE INDICATES LITTLE OVERALL CHANGE IN THE LARGE
SCALE PATTERN DURING THE NEXT DAY OR TWO.

SUBTROPICAL ATLANTIC...
MIDDLE TO UPPER LEVEL RIDGE EXTENDS FROM FLORIDA NEWD OVER THE W
ATLC TO NEAR 30N60W.  THE RIDGE CONTINUES TO BLOCK UPSTREAM
DISTURBANCES KEEPING THE AREA W OF 60W UNDER FAIR WEATHER
CONDITIONS. ADDITIONALLY...STRONG SUBSIDENCE COVERS A GOOD
PORTION OF THE AREA W OF 60W ESPECIALLY JUST W OF AN UPPER LOW
NEAR PUERTO RICO.  OVER THE CENTRAL ATLC...MIDDLE TO UPPER LEVEL
TROUGH EXTENDS FROM 31N55W TO A STRONG UPPER LOW JUST N OF
PUERTO RICO.  INDUCED RIDGING AND DIVERGENT FLOW EAST OF THE
TROUGH IS PRODUCING A LARGE AREA OF CLOUDINESS AND SCATTERED
SHOWERS/THUNDERSTORMS FROM 20N-30N BETWEEN 45W-58W. THE FLOW
BECOMES INCREASINGLY CONVERGENT OVER THE E ATLC IN ASSOCIATION
WITH A MIDDLE TO UPPER LEVEL TROUGH EXTENDING FROM THE CANARY
ISLANDS TO 20N40W.  ASSOCIATED SUBSIDENCE PENETRATES WELL S OF
20N RESTRICTING CONVECTIVE ACTIVITY TO THE ITCZ WITHIN THE
TROPICAL ATLC.  AT THE SURFACE...STRONG 1032 MB HIGH MIGRATING
EWD OVER THE E UNITED STATES IS PUSHING A COLD FRONT OFF THE E
COAST OF THE UNITED STATES ROUGHLY HALFWAY IN BETWEEN THE NORTH
CAROLINA OUTER BANKS AND BERMUDA TO N FLORIDA.  MOST OF THE
UPPER DYNAMICS WITH THIS FRONT ARE CONFINED N OF THE AREA AND
ONLY A FEW ISOLATED SHOWERS ACCOMPANY THE BOUNDARY. STATIONARY
1025 MB HIGH IS POSITIONED OVER THE CENTRAL ATLC NEAR 35N45W
WITH RIDGE AXIS EXTENDING SEWD TO THE COAST OF AFRICA NEAR W
SAHARA.

TROPICAL ATLANTIC...
MIDDLE TO UPPER LEVEL TROUGH OVER THE SUBTROPICAL E ATLC
PENETRATES INTO THE TROPICAL ATLC JUST W OF THE CANARY ISLANDS
WITH ASSOCIATED SUBSIDENCE REACHING THE ITCZ E OF 30W.  MIDDLE
TO UPPER LEVEL RIDGE PREVAILS W OF 30W IS SUPPORTING EXTENSIVE
ITCZ RELATED CLOUDS/CONVECTION ESPECIALLY IN THE VICINITY OF
TROPICAL WAVES NEAR 38W AND 55W.

$$
RHOME


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