[Tropical] Tropical Weather Discussion

[EMWIN Server]

AXNT20 KNHC 122352
TWDAT

TROPICAL WEATHER DISCUSSION
NWS TPC/NATIONAL HURRICANE CENTER MIAMI FL
705 PM EST FRI 12 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.

...ITCZ...
ITCZ AXIS IS ALONG 7N10W 6N40W 9N65W 6N80W. SCATTERED MODERATE
CONVECTION FROM 4N-7N BETWEEN 20W-27W.

...DISCUSSION...

GULF OF MEXICO...
MIDDLE TO UPPER SHORTWAVE TROUGH MOVING THROUGH THE SE UNITED
STATES IS THE PRIMARY WEATHER MAKER AS IT SWEEPS A COLD FRONT
OVER THE GLFMEX FROM THE FLORIDA PANHANDLE TO THE COAST OF
MEXICO NEAR VERACRUZ.  DYNAMICS/LIFT ASSOCIATED WITH THE
SHORTWAVE IS PRODUCING A LINE OF SCATTERED SHOWERS/THUNDERSTORMS
ALONG A PREFRONTAL TROUGH OVER THE FLORIDA PANHANDLE.
HOWEVER...THE BULK OF THIS ENERGY WILL LIFT N OF THE AREA WITH
THE COLD FRONT GRADUALLY BECOMING STATIONARY OVER THE W GLFMEX.
A STRONG HIGH PUSHING EWD FROM THE CENTRAL UNITED STATES SHOULD
PUSH THE REMAINDER OF THE FRONT...E OF 90W...SWD CLEARING S
FLORIDA BY SUNDAY. THERE WILL BE ENOUGH LOW LEVEL MOISTURE
POOLING TO SUPPORT WIDELY SCATTERED SHOWERS AND ISOLATED
THUNDERSTORMS ALONG THE BOUNDARY AS IT SAGS SWD.  ELSEWHERE...
SUBSIDENCE AND DRY AIR PREVAILS LIMITING SIGNIFICANT
CLOUDS/CONVECTION.

CARIBBEAN SEA...
THE SHARP MIDDLE TO UPPER LEVEL TROUGH WHICH HAS AFFECTED THE
CARIBBEAN THROUGH MUCH OF THE WEEK IS FINALLY LIFTING NEWD INTO
THE ATLC. ASSOCIATED BROAD AREA OF SURFACE LOW PRESSURE AND DEEP
CONVECTION HAS PUSHED E OF THE LESSER ANTILLES WITH MIDDLE TO
UPPER LEVEL DRYING NOW OCCURRING. WHILE THIS PATTERN HAS ENDED
THE DEEP CONVECTION...A COLD FRONT HAS PUSHED SWD INTO THE E
CARIBBEAN FROM THE ATLC NEAR ANGUILLA TO 15N70W.  STRONG NE FLOW
BEHIND THE FRONT IS PRODUCING SCATTERED SHOWERS/THUNDERSTORMS
OVER PUERTO RICO WITH WIDELY SCATTERED SHOWERS ELSEWHERE OVER
THE E CARIBBEAN AND LESSER ANTILLES. A WEAK EXTENSION OF THE
FRONT CONTINUES OVER THE CENTRAL AND W CARIBBEAN ALONG 15N/16N
TO CENTRAL AMERICA NEAR THE N COAST OF HONDURAS. WIDELY
SCATTERED SHOWERS ARE OBSERVED WITHIN 60 NM EITHER SIDE OF THE
BOUNDARY. N OF THE FRONT...DRY/STABLE AIR IS SPILLING SWD FROM
THE W ATLC.

ATLANTIC OCEAN...
THE W ATLC REMAINS HIGH AND DRY AS A RIDGE BUILDS FROM CUBA TO
BERMUDA AHEAD OF A PROGRESSIVE TROUGH MOVING THROUGH THE E
UNITED STATES.  MIDDLE TO UPPER LEVEL SUBSIDENCE AND LOWER LEVEL
COLD ADVECTION CONTINUES TO PRODUCE STABLE CONDITIONS W OF A
CENTRAL ATLC COLD FRONT ALONG 32N45W 24N50W INTO THE E CARIBBEAN
NEAR ANGUILLA.  THE PRESSURE GRADIENT BEHIND THE FRONT HAS
RELAXED SINCE YESTERDAY AS STRONG HIGH PRESSURE OVER THE W ATLC
WEAKENS AND LIFTS NEWD.  THE MOST ACTIVE WEATHER REMAINS OVER
THE CENTRAL ATLC WHERE DEEP TROPICAL MOISTURE SURGING NWD IS
INTERACTING WITH A SHARP MIDDLE TO UPPER LEVEL TROUGH AND
ASSOCIATED COLD FRONT. WIDESPREAD CLOUDINESS AND SCATTERED
SHOWERS/THUNDERSTORMS EXTEND NWD FROM 15N TO 28N BETWEEN
45W-60W.  THE STRONGEST AND MOST NUMEROUS OF THIS ACTIVITY IS
LOCATED JUST E OF THE LESSER ANTILLES FROM 16N-20N BETWEEN
50W-60W.  FARTHER E...MIDDLE TO UPPER LEVEL RIDGE EXTENDS FROM A
ANTICYCLONE OVER THE DEEP TROPICAL ATLC NEAR 11N46W NEWD TO
BEYOND 30N40W.  THIS FEATURE IS PRODUCING STRONG SUBSIDENCE AND
DRY AIR S OF 15N BETWEEN 35W-55W EFFECTIVELY SUPPRESSING ITCZ
CONVECTION.  OVER THE FAR E ATLC...NEARLY STATIONARY MIDDLE TO
UPPER LEVEL TROUGH HAS BECOME CUTOFF WITH A CLOSED LOW FORMING
NEAR 26N28W.  A TROUGH TRAILS SWD INTO THE TROPICAL WATERS ALONG
20N27W TO 7N40W.

$$
RHOME


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