[Tropical] Tropical Weather Discussion

[EMWIN Server]

AXNT20 KNHC 091141
TWDAT

TROPICAL WEATHER DISCUSSION
NWS TPC/NATIONAL HURRICANE CENTER MIAMI FL
705 AM EST SAT DEC 09 2006

TROPICAL WEATHER DISCUSSION FOR NORTH AMERICA...
CENTRAL AMERICA...THE GULF OF MEXICO...THE CARIBBEAN SEA...
NORTHEASTERN SECTIONS OF SOUTH AMERICA...AND THE ATLANTIC
OCEAN TO THE AFRICAN COAST FROM THE EQUATOR TO 32N.
THE FOLLOWING INFORMATION IS BASED ON SATELLITE IMAGERY...
METEOROLOGICAL ANALYSIS...WEATHER OBSERVATIONS...AND RADAR.

BASED ON 0600 UTC SURFACE ANALYSIS AND SATELLITE IMAGERY THROUGH
1115 UTC.

...THE ITCZ...
ITCZ AXIS IS CENTERED ALONG 7N12W 5N30W 4N40W 5N50W 6N56W.
SCATTERED MODERATE/ISOLATED CONVECTION IS FROM 2N-6N BETWEEN
41W-56W. THIS CONVECTIVE ACTIVITY IS AFFECTING PARTS OF FRENCH
GUIANA AND SURINAME...AND THE ADJACENT COASTAL WATERS.

...DISCUSSION...
THE GULF OF MEXICO...
A SHORT WAVE TROUGH IS OVER TEXAS AND NE MEXICO. SWLY WINDS
AHEAD OF THE UPPER TROUGH ARE CARRYING ABUNDANT MOISTURE AND
HIGH CLOUDS ACROSS MUCH OF THE GULF AND THE STATE OF FLORIDA.
AT THE SURFACE...A STRONG 1036 MB SFC HIGH PRESSURE LOCATED OVER
ALABAMA COVERS THE SE U.S. AND THE GULF...INCLUDING ALSO THE
FLORIDA PENINSULA. THIS FEATURE IS PRODUCING WIDESPREAD 20 TO
25 KT NE FLOW ACROSS THE GULF...WITH WINDS NEAR GALE FORCE IN
THE SW PORTION. THE BROWNSVILLE DOPPLER RADAR SHOWS AN AREA OF
SCATTERED TO NUMEROUS SHOWERS AND ISOLATED TSTMS OVER THE NW
CORNER OF THE GULF...WHILE LIGHT RAIN IS AFFECTING NE MEXICO.
LINES OF MAINLY LIGHT SHOWERS ARE SEEN OVER THE STRAITS OF
FLORIDA. THIS SHOWER ACTIVITY IS REACHING HAVANA CUBA UNDER A
NELY WIND FLOW. THE HIGH PRES WILL SLOWLY SHIFT E TODAY WITH
DIMINISHING WINDS AND SEAS OVER THE W GULF. STRONG NE TO E WINDS
WILL REMAIN OVER THE SE GULF AND THE STRAITS OF FLORIDA DURING
THE REST OF THE WEEKEND.

CARIBBEAN SEA...
WLY UPPER LEVEL FLOW ALSO DOMINATES THE NW QUADRANT OF THE
CARIBBEAN SEA AND WESTERN CUBA. A RIDGE EXTENDS FROM NORTHERN
COLOMBIA ACROSS THE E CARIBBEAN TO THE LEEWARD ISLANDS INTO THE
CENTRAL ATLC. DRY AIR ALOFT/SUBSIDENCE COVERS THE E CARIBBEAN
WITH ONLY PATCHES OF LOW LEVEL MOISTURE EMBEDDED IN THE TRADE
WINDS. A STATIONARY FRONT EXTENDS OVER THE NW CARIBBEAN FROM THE
GULF OF HONDURAS TO EASTERN CUBA...THEN CONTINUES AS A COLD
FRONT OVER THE SOUTHERN BAHAMAS AND THE W ATLC. A SFC TROUGH
REMAINS AHEAD OF THE FRONT AND LIES ALONG 80W/81W. BOTH...THE
STATIONARY FROM 12N-19N W OF 80W. A DIFFLUENT PATTERN ALOFT IS
ENHANCING THIS SHOWER/TSTM ACTIVITY. NE WINDS IN THE 20-25 KT
RANGE ARE BLOWING BEHIND THE FRONT OVER THE YUCATAN CHANNEL AND
THE NW CARIBBEAN. THE SFC TROUGH WILL MOVE EWD INTO CENTRAL
AMERICA GENERATING ISOLATED TO SCATTERED CONVECTION OVER THE
AREA. MODEL GUIDANCE SUGGESTS THE WRN CARIBBEAN WILL CONTINUE TO
SEE SCATTERED SHOWERS/TSTMS THROUGH THE REST OF THE WEEKEND...
WITH SPEED CONVERGENCE AND THE OLD FRONTAL BOUNDARY MEANDERING.
HIGH PRES N OF THE AREA WILL MAINTAIN MODERATE TO FRESH ELY
WINDS THROUGH MONDAY.

THE ATLANTIC OCEAN...
STRONG SFC HIGH PRESSURE IS BUILDING INTO THE SW NORTH ATLC OFF
THE FLORIDA COAST...FROM A 1036 MB CENTER OVER ALABAMA. THIS
SYSTEM IS PRODUCING FRESH TO STRONG NE WINDS OVER MUCH OF THE
AREA N OF 22N AND W OF 65W...JUST BEHIND A COLD FRONT THAT
ENTERS THE AREA NEAR 31N59W THEN CONTINUES SW ACROSS EASTERN
CUBA AND THE NW CARIBBEAN WHERE IT BECOMES STATIONARY. UPPER
FLOW OVER THE SW NORTH ATLC IS MOSTLY SW AHEAD OF THE UPPER
TROUGH OVER THE ERN SEABOARD. DIFFLUENCE BETWEEN THIS FEATURE
AND AN UPPER RIDGE EXTENDING NE THROUGH THE LEEWARD ISLANDS INTO
THE CENTRAL ATLC IS HELPING TO SUPPORT THE CONVECTIVE ACTIVITY
ASSOCIATED WITH THE FRONT. AN UPPER TROUGH EXTENDS FROM AN UPPER
LOW SITUATED NEAR 21N35W TO JUST E OF THE LESSER ANTILLES NEAR
15N60W. AN UPPER RIDGE EXTENDS UP THE COAST OF W AFRICA.
ABUNDANT UPPER LEVEL MOISTURE IS BEEN ADVECTED FROM THE DEEP
TROPICS NEWD ACROSS THE CAPE VERDE/CANARY ISLANDS. A 1040 MB SFC
HIGH PRES OVER THE AZORES REMAINS IN CONTROL OF THE WEATHER
PATTERN OVER THE E-CENTRAL ATLC PRODUCING MODERATE TO FRESH ELY
WINDS. PATCHES OF LOW LEVEL MOISTURE WITH EMBEDDED LIGHT SHOWERS
ARE OBSERVED UNDER THE INFLUENCE OF THIS SYSTEM.

$$
GR




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