[Tropical] Tropical Weather Discussion

[EMWIN Server]

AXNT20 KNHC 042351
TWDAT

TROPICAL WEATHER DISCUSSION
NWS TPC/NATIONAL HURRICANE CENTER MIAMI FL
705 PM EST TUE 04 JAN 2005

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.

...ITCZ...

ITCZ AXIS IS CENTERED ALONG 7N10W 3N30W 7N45W 3N60W 4N80W.
ISOLATED MODERATE CONVECTION IS FROM THE EQUATOR TO 6N BETWEEN
22W AND 50W.

...DISCUSSION...

GULF OF MEXICO...
STRONG MID/UPPER LEVEL RIDGING REMAINS OVER THE GLFMEX WITH AXIS
EXTENDING FROM A ANTICYCLONE OVER THE BAY OF CAMPECHE NEWD TO
THE FLORIDA PANHANDLE. THE PERSISTENT RIDGING CONTINUES TO KEEP
UPSTREAM DISTURBANCES N OF THE AREA AND LIMIT THE INTRUSION OF
COLD CONTINENTAL AIR.  A MIDDLE TO UPPER LEVEL MOISTURE PLUME IS
NOTED IN WATER VAPOR IMAGERY OVER THE NORTHERN GLFMEX N OF 26N.
STRONG SUBSIDENCE IS S OF 26N LEAVING THE SOUTHERN GLFMEX
DRY/TRANQUIL.  AT THE SURFACE...HIGH PRESSURE OVER THE W ATLC IS
PRODUCING YET ANOTHER DAY OF BRISK ELY FLOW OVER S FLORIDA AND
THE SE GLFMEX WITH MODERATE RETURN FLOW OVER THE W GULF.  THIS
PATTERN HAS REMAINED NEARLY UNCHANGED FOR OVER A WEEK BUT
NUMERICAL GUIDANCE INDICATES A COLD FRONT WILL FINALLY PENETRATE
THE AREA WED INTO THU WITH THE SURFACE RIDGE SLIDING SWD OVER
FLORIDA.  THIS PATTERN SHOULD PRODUCE INCREASING WINDS BEHIND
THE FRONT THU WITH DECREASING WINDS OVER THE REMAINDER OF THE
AREA.  CLOUDINESS AND SHOWERS/THUNDERSTORMS WILL ALSO BE ON THE
INCREASE OVER THE NW GLFMEX AS THE FRONT EMERGES OFF SE TEXAS
EARLY THU.

CARIBBEAN...
THE AREA REMAINS UNDER THE INFLUENCE OF STRONG MIDDLE TO UPPER
LEVEL TROUGH EXTENDING FROM THE ATLC OVER HISPANIOLA TO CENTRAL
AMERICA NEAR COSTA RICA.  STRONG SUBSIDENCE OVER THE CONFLUENT
SIDE OF THE UPPER TROUGH BLANKETS THE CARIBBEAN W OF 70W
PRODUCING DRY/STABLE CONDITIONS ABOVE 800 MB.  WEAK UPPER LEVEL
DIFFLUENCE EXIST OVER THE E CARIBBEAN CONTRIBUTING TO AN AREA OF
SHOWERS/THUNDERSTORMS ALONG A WEAK LOW LEVEL ELY DISTURBANCE E
OF 70W.  SURFACE TRADEWIND ACTIVITY IS PRODUCING SCATTERED
SHOWERS OVER COASTAL REGIONS OF CENTRAL AMERICA FROM COSTA RICA
TO THE YUCATAN PENINSULA.

ATLANTIC...
MIDDLE TO UPPER LEVEL RIDGE EXTENDS FROM THE GLFMEX OVER CENTRAL
FLORIDA TO THE W ATLC BEYOND BERMUDA.  THE SUBTROPICAL JET AND
ASSOCIATED MOISTURE LIES ALONG THE N PERIPHERY OF THE RIDGE
CREATING A SHARP DELINEATION IN MOISTURE ALONG THE RIDGE AXIS.
CONFLUENT FLOW S OF THE AXIS IS GENERATING DRY/STABLE CONDITIONS
WHICH EXTENDS EWD ACROSS THE CENTRAL ATLC TO A LARGE UPPER LOW
NEAR 29N49W. AN UPPER TROUGH TRAILS SWD FROM THE LOW INTO THE
CARIBBEAN OVER HISPANIOLA. ENHANCED INSTABILITY ASSOCIATED WITH
THE COLD CORE LOW IS GENERATING SCATTERED MODERATE CONVECTION
OVER THE N PORTION OF THE AREA N OF 28N BETWEEN 36W-50W.  AT THE
SURFACE...A 1008 MB LOW IS LOCATED NEAR 27N49W WITH A BROAD
TROUGH TRAILING SWD ALONG 18N50W TO TRINIDAD/TOBAGO.  SCATTERED
SHOWERS AND ISOLATED THUNDERSTORMS ARE OBSERVED WITHIN SEVERAL
DEGREES EITHER SIDE OF THE BOUNDARY WITH BROKEN STRATOCUMULUS
CLOUDS AND WIDELY SCATTERED SHOWERS ELSEWHERE TO 65W.  OVER THE
E ATLC...A LARGE UPPER LEVEL CUTOFF LOW IS LOCATED ALONG THE
COAST OF W SAHARA NEAR 23N17W WITH ASSOCIATED SUBSIDENCE OVER
THE CANARY ISLANDS AND ATLC WATERS N OF 20N E OF 30W.  FURTHER
S...A BROAD MIDDLE TO UPPER LEVEL RIDGE EXTENDS NWD FROM THE
TROPICAL ATLC ALONG 40W TO BEYOND 32N33W. A SUBTROPICAL JET
ALONG THE N PERIPHERY IS PRODUCING ENHANCED ITCZ ACTIVITY
BETWEEN 25W-45W.

$$
FORMOSA





This weather bulletin was brought to you by:
www.nashvilleweather.net