[Tropical] Tropical Weather Discussion

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AXNT20 KNHC 050001
TWDAT

TROPICAL WEATHER DISCUSSION
NWS TPC/NATIONAL HURRICANE CENTER MIAMI FL
705 PM EST THU 04 NOV 2004

TROPICAL WEATHER DISCUSSION FOR NORTH AMERICA...CENTRAL
AMERICA...GULF OF MEXICO...CARIBBEAN SEA...NORTHEASTERN SECTIONS
OF SOUTH AMERICA...AND 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 1800 UTC SURFACE ANALYSIS AND SATELLITE IMAGERY THROUGH
2315 UTC.

...TROPICAL WAVES...
TROPICAL WAVE LOCATED OVER THE W CARIBBEAN/CENTRAL AMERICA ALONG
88W S OF 20N MOVING W 15 KT. DIVERGENT PATTERN ALOFT IS
PROVIDING THE SUPPORT FOR AN AREA OF SCATTERED MODERATE
CONVECTION FROM 12N-17N BETWEEN 80W-84W AND MORE WIDELY
SCATTERED ACTIVITY IN OTHERS AREAS FROM 11N-20N BETWEEN
79W-90W.   THIS ACTIVITY IS SPREADING FARTHER INLAND AND WILL
PRODUCE LOCALLY HEAVY RAINFALL OVER CENTRAL AMERICA N OF COSTA
RICA THRU THE YUCATAN PENINSULA DURING THE NEXT DAY OR TWO.

...ITCZ...
ITCZ AXIS IS ALONG 10N13W 7N25W 10N45W 11N60W.  WIDELY SCATTERED
MODERATE FROM 4N-10N BETWEEN 20W-31W.  ISOLATED MODERATE WITHIN
45 NM OF 4N16W TO 6N10W.  SCATTERED MODERATE WITHIN 120 NM OF
6N37W.  WIDELY SCATTERED SHOWERS IN THE WINDWARD ISLANDS AT THE
NW EDGE OF THE ITCZ FROM BARBADOS S TO 9N BETWEEN 55W-65W.

...DISCUSSION...
GULF OF MEXICO...
UPPER TROUGHING HAS REALLY WEAKENED OVER THE PAST 24 HOURS AS A
MID/UPPER LEVEL CLOSED LOW LEAVES THE USA WITH JUST BROAD
TROUGHING OVER THE NW GULF.  THIS HAS REALLY SLOWED DOWN THE
PROGRESS OF THE ASSOCIATED COLD FRONT FROM NEAR TALLAHASSEE SWD
INTO THE BAY OF CAMPECHE NEAR 18N94W.  THERE ARE FEW UPPER
DYNAMICS TO WORK WITH AND...CONSEQUENTLY...ANY PRECIPITATION
ALONG THE FRONT HAS BECOME ISOLATED AND WEAKER THAN YESTERDAY.
THE EXTREME S EXTENT OF THE FRONT HAS BECOME NEARLY STATIONARY.
HOWEVER...THE PATTERN IS EXPECTED TO BECOME MORE PROGRESSIVE AS
A WEAK SHORTWAVE MOVES E THRU TEXAS INTO THE GULF.  THIS
DISTURBANCE SHOULD KICK THE FRONT EWD ...CLEARING S FLORIDA BY
LATE FRI.  UPPER LIFT WILL REMAIN LIMITED BUT LOW LEVEL MOISTURE
POOLING SHOULD PRODUCE SCATTERED SHOWERS/ISOLATED TSTMS.  HIGH
PRESSURE CONTINUES BEHIND THE FRONT OVER THE W GULF BUT  WINDS
HAVE RELAXED SINCE YESTERDAY'S GALE EVENT.  THE REST OF THE GULF
HAS A STRONG DEEP LAYERED RIDGE EXTENDING FROM THE BAHAMAS W TO
THE CENTRAL GULF NEAR 24N90W.  SUBSIDENCE AND MIDDLE/UPPER DRY
AIR IS LEAVING QUIET CONDITIONS OVER S FLORIDA AND THE SE GULF.

CARIBBEAN...
THE W CARIBBEAN REMAINS THE MOST ACTIVE IN TERMS OF DEEP
CONVECTION COURTESY OF A TROPICAL WAVE ALONG 88W. BROADLY
DIVERGENT FLOW IS OVER THE AREA ENHANCING THE WAVE'S CONVECTION.
THE DIVERGENT FLOW ASSOCIATED WITH A DEVELOPING ANTICYCLONE OVER
THE SW CARIBBEAN.  DEEPER MOISTURE IS SLOWLY PUSHING TOWARD
CUBA.  IN THE E CARIBBEAN...DEEP-LAYERED TROUGH CONTINUES
SAGGING S FROM THE LEEWARD ISLANDS TO THE CENTRAL CARIBBEAN NEAR
14N74W.  VERY DRY AIR IN THE MID/UPPER LEVELS HAS CUT OFF ANY
DEEP CONVECTION THOUGH ISOLATED SHOWERS ARE POSSIBLE N OF THE
TROUGH AXIS.  S OF THE AXIS...WIDELY SCATTERED SHOWERS ARE E OF
70W.  THE TROUGH SHOULD CONTINUE TO DROP SWD TO THE N COAST OF S
AMERICA DURING THE NEXT DAY OR SO ALLOWING DRY/STABLE CONDITIONS
TO INFILTRATE THE ENTIRE E CARIBBEAN.

SUBTROPICAL ATLANTIC...
W ATLC IS COVERED BY A DEEP LAYERED RIDGE OVER THE NW BAHAMAS
WITH STRONG SUBSIDENCE AND ASSOCIATED DRY AIR LEAVING ONLY
SHALLOW SHOWERS POSSIBLE W OF 60W.  A COLD FRONT IS RAPIDLY
MOVING SWD ALONG 31N48W TO 27N63W STATIONARY TO 31N72W WITH
SCATTERED SHOWERS WITHIN 60 NM OF THE FRONT.  DISSIPATING
STATIONARY FRONT EXTENDS FROM 31N38W TO 24N43W THEN 19N62W.
ISOLATED MODERATE N OF 26N BETWEEN 27W-32W ALONG A WEAKENING
TROUGH BOUNDARY.  THESE FRONTS/TROUGHS WERE FORMED BY A BROAD
TROUGH OVER THE CENTRAL ATLC WITH EXITING ENERGY ALONG 25W AND A
NEW TROUGH DIVING S ALONG 31N54W TO 25N61W.   DEEP INTRUSIONS OF
MID-LATITUDE ENERGY APPEAR LIKELY UNTIL UPPER RIDGING DIMINISHES
OVER THE W ATLC IN A COUPLE OF DAYS.  A SMALL UPPER LOW NEAR
30N16W NEAR THE CANARY ISLANDS IS PRODUCING SCATTERED
SHOWERS/TSTMS JUST N OF THE CANARY ISLANDS.

TROPICAL ATLANTIC...
LITTLE CHANGE WITH A MID/UPPER LEVEL RIDGE REMAINING OVER THE E
TROPICAL ATLC ALONG 10N/11N E OF 40W. DIFFLUENCE NEAR THE RIDGE
AXIS IS ENHANCING ITCZ CONVECTION E OF 35W. STRONG WLY UPPER
FLOW ASSOCIATED WITH AN E/W ORIENTED SUBTROPICAL JET FROM THE E
CARIBBEAN TO W AFRICA NEAR MAURITANIA PENETRATES INTO THE
TROPICAL REGION W OF 40W.

$$
BLAKE

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