[Tropical] Tropical Weather Discussion

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AXNT20 KNHC 291736
TWDAT

TROPICAL WEATHER DISCUSSION
NWS TPC/NATIONAL HURRICANE CENTER MIAMI FL
105 PM EST MON 29 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 1200 UTC SURFACE ANALYSIS AND SATELLITE IMAGERY THROUGH
1715 UTC.

SPECIAL FEATURES...
DEEP LAYERED NON-TROPICAL AREA OF LOW PRESSURE IS CENTERED IN
THE NORTH- CENTRAL ATLC NEAR 29.5N48W 1001 MB...MOVING NW 10 KT.
THIS POSITION IS ABOUT 850 NM ESE OF BERMUDA...ALSO ABOUT 1000
NM SW OF THE WESTERNMOST AZORES ISLANDS. THIS SYSTEM CONTINUES
TO SHOW SOME POTENTIAL FOR SUBTROPICAL DEVELOPMENT DURING THE
NEXT COUPLE OF DAYS. VISIBLE SATELLITE IMAGERY INDICATES THAT
THE LOW-LEVEL CIRCULATION ASSOCIATED WITH THE LOW HAS BECOME
MORE COMPACT AND THE OVERALL SYSTEM LOOKS A LITTLE BETTER
ORGANIZED. GALE FORCE WINDS ARE N OF 31N. CLOSER TO THE
LOW...SMALL BANDS OF MODERATE CONVECTION ARE WITHIN 90-120 N AND
E OF THE LOW. ANOTHER AREA OF MODERATE CONVECTION IS NW OF THE
LOW FROM 32N53W TO 28N52W. OCCLUDED FRONT WRAPS AROUND THE W
SIDE OF THE LOW TO 31N49W...THEN ESE TO TRIPLE POINT NEAR
29N42W. STATIONARY FRONT THEN EXTENDS ESE FROM TRIPLE POINT TO
26N32W. CLUSTERS OF SCATTERED MODERATE CONVECTION ARE ALONG AND
JUST N OF THE FRONTAL BOUNDARIES. WIDELY SCATTERED
SHOWERS/POSSIBLE TSTMS ARE DEVELOPING SW OF THE TRIPLE POINT
FROM 26N-28N BETWEEN 43W-45W...A POSSIBLE INDICATION OF WARMER
AND UNSTABLE AIR WRAPPING AROUND THE SYSTEM.

...ITCZ...

ITCZ AXIS IS CENTERED ALONG 6N11W 7N28W 10N46W 10N61W. SCATTERED
MODERATE/ISOLATED STRONG CONVECTION IS WITHIN 60 NM OF AXIS
BETWEEN 30W-37W. SCATTERED MODERATE CONVECTION IS WITHIN
120 NM N OF AXIS BETWEEN 37W-43W...AND ALONG THE ITCZ JUST E OF
TRINIDAD. SCATTERED MODERATE CONVECTION S OF AFRICA COAST FROM
1N-4N BETWEEN 2W-5W IS WELL S OF ITCZ AXIS WHICH IS INLAND OVER
AFRICA.

...DISCUSSION...

GULF OF MEXICO INTO W ATLANTIC AND NW CARIBBEAN...
SPRAWLING MID/UPPER LEVEL HIGH DOMINATES THIS AREA WHICH EXTENDS
AS FAR E AS THE BAHAMAS AND SOUTHWARD ACROSS CUBA...JAMAICA...
AND NW CARIBBEAN N OF 15N TO OVER YUCATAN PENINSULA. A MID-LEVEL
ANTICYCLONIC CIRCULATION CENTER OVER W CUBA. UPPER LEVEL FLOW IS
ANTICYCLONIC OVER THIS REGION...WITH WATER VAPOR IMAGERY AND
RAWINSONDE DATA INDICATING DRY AIR IN THE MID LEVELS PREVAILING
ACROSS MUCH OF THE AREA. SW UPPER LEVEL WINDS INCREASE TO 70-80
KT ALONG THE U.S. GULF COAST WHERE AN INCREASE IN UPPER LEVEL
MOISTURE IS NOTED. AT THE SURFACE...A WEAKENING STATIONARY FRONT
EXTENDS ACROSS CENTRAL AND WESTERN CUBA TO THE YUCATAN CHANNEL
WHERE IT BECOMES A WARM FRONT TO OVER THE SW GULF NEAR 24N93W.
THE HIGH IS EXPECTED TO MOVE LITTLE OVER THE NEXT 24-36
HOURS...KEEPING MAINLY DRY CONDITIONS ACROSS THE AREA. A COLD
FRONT CURRENTLY OVER N TEXAS IS FORECAST TO MOVE INTO THE NW
GULF OF MEXICO IN 24-30 HOURS...WITH INCREASING MOISTURE AND
SCATTERED SHOWERS/ISOLATED TSTMS EXPECTED ALONG THE FRONT.

W ATLANTIC BETWEEN 60W-75W AND REMAINDER CARIBBEAN...
MID/UPPER LEVEL FLOW IS PREDOMINANTLY W-NW ACROSS THIS AREA WITH
AN EMBEDDED SHORTWAVE TROUGH FROM 32N60W-24N63W TO ACROSS
HISPANIOLA AND PUERTO RICO TO CARIBBEAN NEAR 15N80W. MUCH OF
THIS AREA IS UNDER MODERATE SUBSIDENCE...WITH CONFLUENT UPPER
FLOW W OF TROUGH PRODUCING LOCALLY STRONG SUBSIDENCE/DRY AIR
NOTED OVER CARIBBEAN SEA S OF HISPANIOLA. AT THE SURFACE...A
COLD FRONT EXTENDS FROM VICINITY OF BERMUDA SW TO 24N75W WHERE
IT THEN BECOMES STATIONARY ACROSS CENTRAL BAHAMAS TO CENTRAL
CUBA. ISOLATED SHOWERS/TSTMS ARE ALONG THE FRONT MAINLY N OF
26N...WITH WIDELY SCATTERED SHOWERS/TSTMS FURTHER E NEAR
MID/UPPER SHORTWAVE TROUGH AXIS. MOST OF CARIBBEAN SEA REMAINS
FREE OF SIGNIFICANT CLOUD COVER. ONLY EXCEPTIONS ARE OVER SW
CARIBBEAN WHERE BROKEN/OVERCAST LOW/MID CLOUDS WITH ISOLATED
SHOWERS ARE MOVING W ON THE LEADING EDGE OF STRONGER SURFACE NE
WINDS APPROACHING THE CENTRAL AMERICA COAST...AND NEAR THE
COLOMBIA AND WESTERN VENEZUELA COAST WHERE BROKEN/OVERCAST
LOW-MID CLOUDS WERE ALSO NOTED. SHORTWAVE TROUGH IS EXPECTED TO
MOVE EASTWARD OVER THE NEXT 24-48 HOURS...KEEPING AREA UNDER
MOSTLY DRY NORTHERLY FLOW ALOFT.

CENTRAL ATLANTIC BETWEEN 40W-60W...
THIS AREA IS DOMINATED BY THE DEEP LAYERED NON-TROPICAL LOW
DESCRIBED IN THE SPECIAL FEATURES SECTION. CYCLONIC MID/UPPER
LEVEL CIRCULATION IS NEAR 29N49W...JUST W OF THE SURFACE
LOW...WITH MID/UPPER TROUGH AXIS EXTENDING SW TO ALONG
24N53W-16N56W. UPPER LEVEL FLOW IS PREDOMINANTLY W-SW AND
CYCLONIC N OF TROUGH...WITH ZONAL FLOW S OF TROUGH. DISSIPATING
SURFACE FRONT EXTENDS FROM 28N41W-19N53W...WITH DIFFLUENT UPPER
LEVEL FLOW HELPING TO SUPPORT SCATTERED MODERATE CONVECTION SE
OF THIS BOUNDARY FROM 16N-20N BETWEEN 40W-45W. ANOTHER AREA OF
SCATTERED MODERATE CONVECTION IS ALONG AN AREA OF WEAK LOW LEVEL
CONVERGENCE FROM 11N58W-14N53W-16N49W. THE DEEP LAYERED LOW IS
EXPECTED TO MOVE NW-N OVER THE NEXT 24-48 HOURS AS THE MID/UPPER
TROUGH DROPS SE AND REMAINS ACROSS THIS AREA. THIS WILL HELP TO
CONTINUE PRODUCING SHOWERS/TSTMS MAINLY BETWEEN 40W-50W IN
STRONGLY DIFFLUENT UPPER FLOW.

ATLANTIC E OF 40W...
MID/UPPER RIDGE FROM 26N33W THROUGH 32N35W IS WEDGED BETWEEN THE
DEEP-LAYERED LOW DESCRIBED IN THE SPECIAL FEATURES SECTION AND
ANOTHER DEEP LAYERED LOW CENTERED N OF AREA NEAR 34N16W. UPPER
FLOW IS STRONGLY CYCLONIC N OF 27N E OF 30W IN ASSOCIATION WITH
THE LOW NEAR 34N16W. SATELLITE-DERIVED UPPER LEVEL WINDS OF
60-70 KT ARE N OF 28N E OF 27W...DROPPING S TO NEAR 28N21W...
THEN NE ACROSS CANARY ISLANDS. SURFACE COLD FRONT EXTENDS FROM
OVER CANARY ISLANDS S TO NEAR 24N17W...WITH A NARROW BAND OF
BROKEN/OVERCAST MULTI-LAYERED CLOUDS AND POSSIBLE SHOWERS E OF
FRONT TO THE COAST OF MOROCCO. BROKEN/OVERCAST LOW CLOUDS WITH
SCATTERED SHOWERS ARE ALSO OVER NE PORTION OF AREA JUST S OF THE
LOW CENTER. BAND OF SHOWERS/TSTMS EXTENDS ALONG STATIONARY FRONT
ASSOCIATED WITH THE CENTRAL ATLC DEEP-LAYERED LOW FROM 28N41W
TO 26N32W. ZONAL FLOW CONTINUES ACROSS TROPICAL PORTION OF AREA
ALL THE WAY TO THE AFRICAN COAST NEAR 19N16W. S OF THIS AREA...A
MID/UPPER LEVEL HIGH IS CENTERED N OF BRAZIL COAST NEAR 2N38W.
DIFFLUENT FLOW BETWEEN THE HIGH AND THE SW FLOW FARTHER TO THE N
IS ENHANCING ITCZ CONVECTION W OF 30W. UPPER FLOW IS EXPECTED TO
AMPLIFY ACROSS THE AREA DURING THE NEXT 24-48 HOURS AS LOW NEAR
34N16W MOVES E AND DOWNSTREAM RIDGE STRENGTHENS NEAR 35W.

$$
MOLLEDA


WWWW
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