[Tropical] Tropical Weather Discussion

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AXNT20 KNHC 161752
TWDAT

TROPICAL WEATHER DISCUSSION
NWS TPC/NATIONAL HURRICANE CENTER MIAMI FL
105 PM EST TUE 16 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.

...ITCZ...

ITCZ AXIS IS ALONG 10N10W 6N30W 7N43W 4N55W 8N73W 7N80W.
SCATTERED MODERATE TO STRONG CONVECTION FROM 3N-6N BETWEEN
10W-30W. WIDELY SCATTERED MODERATE CONVECTION FROM 3N-10N
BETWEEN 33W-43W.

...DISCUSSION...

GULF OF MEXICO...
LARGE UPPER LEVEL CLOSED LOW OVER NW MEXICO IS THE MAIN WEATHER
MAKER FOR THE GLFMEX AS DIFFLUENT UPPER LEVEL FLOW TO THE EAST
PRODUCES WIDESPREAD CLOUDINESS AND SCATTERED SHOWERS/
THUNDERSTORM N OF 22N W OF 90W. SIMILAR ACTIVITY IS ALSO NOTED
OVER INTERIOR MEXICO ALONG THE E SLOPES OF THE SIERRA MADRE
ORIENTALS BETWEEN 100W-105W.  THIS ACTIVITY EXTENDS NWD AND
BECOMES INCREASINGLY NUMEROUS OVER W PORTIONS OF TEXAS IN LINE
WITH THE BEST UPPER DYNAMICS.  THE UPPER LOW IS FLANKED ON THE
WESTERN SIDE BY A 70-90 KT NLY JET INDICATING THE TROUGH WILL
UNDERGO AMPLIFICATION AND BECOME NEGATIVELY TILTED DURING THE
NEXT 24 HOURS.  AS THIS EVOLUTION OCCURS...MIDDLE TO UPPER LEVEL
DYNAMICS/LIFT WILL INCREASE AND SLIDE EWD INTO CENTRAL TEXAS AND
THE NW GLFMEX. THIS PATTERN WILL SUPPORT INCREASING
SHOWERS/THUNDERSTORMS EXTENDING FROM TEXAS SWD INTO THE NW
GLFMEX...MAINLY N OF 25N.  SHIFTING EWD...STRONG MIDDLE TO UPPER
LEVEL RIDGE BISECTS THE CENTRAL GULF ALONG 90W EXTENDING NWD
WELL INTO THE CENTRAL UNITED STATES.  UPSTREAM DYNAMICS AND
MOISTURE IS RIDING UP AND OVER THE RIDGE LEAVING SUBSIDENCE AND
DRY AIR OVER THE E GLFMEX AND FLORIDA.  LOWER LEVEL MOISTURE IS
ALSO ABSENT OVER THIS REGION AND THE PRESENCE OF STRATOCUMULUS
CLOUDS IN SATELLITE IMAGERY INDICATES COLD ADVECTION AND STABLE
CONDITIONS.

CARIBBEAN SEA...
A LARGE MIDDLE TO UPPER LEVEL TROUGH OVER THE W ATLC PENETRATES
WELL INTO THE CENTRAL CARIBBEAN FROM THE MONA PASSAGE TO CENTRAL
AMERICA NEAR THE COSTA RICA/PANAMA BORDER.  ASSOCIATED CONFLUENT
FLOW ON THE BACKSIDE OF THE TROUGH IS PRODUCING STRONG MIDDLE TO
UPPER LEVEL SUBSIDENCE AND VERY DRY AIR.  THIS PATTERN IS
EFFECTIVELY CAPPING SIGNIFICANT CLOUDS/CONVECTION.  ATTENDANT
COLD FRONT ENTERS THE AREA THROUGH THE WINDWARD PASSAGE BECOMING
STATIONARY AS IT MAKES ITS WAY ACROSS THE NW CARIBBEAN TO N
BELIZE.  STRONG HIGH PRESSURE BEHIND THE FRONT CONTINUES TO
PRODUCING BRISK NE FLOW AND COLD ADVECTION.  OVER THE E
CARIBBEAN...MIDDLE TO UPPER LEVEL DIFFLUENT FLOW IS TRIGGERING
SCATTERED SHOWERS/THUNDERSTORMS PRIMARY ALONG A LOW LEVEL TROUGH
EXTENDING ACROSS THE WINDWARD ISLANDS NEAR ST. LUCIA TO JUST OFF
THE COAST OF COLOMBIA NEAR 11N75W.  THE UPPER TROUGH OVER THE
CENTRAL ATLC AND CARIBBEAN WILL CONTINUE TO BE REINFORCED DURING
THE NEXT FEW DAYS BY SHORTWAVES DROPPING SWD FROM THE E UNITED
STATES.  THIS SHOULD MAINTAIN A BAND OF MIDDLE TO UPPER LEVEL
LIFT AND ASSOCIATED SHOWERS/THUNDERSTORMS FROM THE SW CARIBBEAN
TO THE WINDWARD ISLANDS.  THIS ACTIVITY MAY BECOME MORE
NUMEROUS/STRONG TOWARD THE END OF THE WEEK AS A STRONG
SUBTROPICAL JET FORMS OVER THE CENTRAL ATLC.

ATLANTIC OCEAN...
THE PERSISTENT HIGH AMPLITUDE TROUGH PATTERN REMAINS OVER THE W
ATLC WITH AXIS CURRENTLY EXTENDING FROM 31N60W SWD INTO THE
CARIBBEAN NEAR THE MONA PASSAGE. THE ATTENDANT COLD FRONT ENTERS
THE AREA NEAR 32N50W SW ALONG 23N60W TO THE N COAST OF
HISPANIOLA WHERE IT BECOMES STATIONARY ACROSS THE NW CARIBBEAN.
STRONG SUBSIDENCE AND DRY NW FLOW BEHIND THE UPPER TROUGH
CONTINUES TO AFFECT THE AREA  W OF THE FRONT ALL THE WAY TO THE
E UNITED STATES COAST WITH ASSOCIATED STABLE CONDITIONS LIMITING
CLOUDS TO COLD AIR STRATOCUMULUS.  A 1034 MB SURFACE HIGH OVER
THE SE UNITED STATES IS BUILDING IN BEHIND THE COLD FRONT
PRODUCING STRONG NE FLOW.  MIDDLE TO UPPER LEVEL DYNAMICS WITH
THE UPPER TROUGH IS WELL AHEAD OF THE COLD FRONT PRODUCING AN
AREA OF CONVECTION OVER THE CENTRAL ATLC NE A 1004 SURFACE LOW
NEAR 26N48W. WIDELY SCATTERED MODERATE CONVECTION IS ALSO NOTED
WITHIN 300 NM AHEAD OF A TRAILING TROUGH EXTENDING SW TO THE
WINDWARD ISLANDS NEAR 14N.  OVER THE CENTRAL AND E ATLC...MIDDLE
TO UPPER LEVEL RIDGE EXTENDS NWD FROM A WELL-DEFINED ANTICYCLONE
OVER THE TROPICAL ATLC NEAR 11N45W TO BEYOND 31N43W. A SHORTWAVE
TROUGH LIES OVER THE FAR E ATLC NEAR 30W WITH A MUCH STRONGER
TROUGH EXTENDING SWD FROM EUROPE OVER NW AFRICA.  OVER THE
TROPICAL ATLC...ITCZ CONVECTION IS MOST PRONOUNCED BETWEEN
10W-30W IN ASSOCIATION WITH A SUBTROPICAL JET SE OF THE CAPE
VERDE ISLANDS.  THIS JET IS EXPECTED TO REMAIN OVER THE AREA
DURING THE NEXT DAY OR SO KEEPING THE E PORTION OF THE ITCZ
ACTIVE.

$$
RHOME


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