[Tropical] Tropical Weather Discussion

[EMWIN Server]

AXNT20 KNHC 082346
TWDAT

TROPICAL WEATHER DISCUSSION
NWS TPC/NATIONAL HURRICANE CENTER MIAMI FL
705 PM EST WED NOV 08 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...WEATHER OBSERVATIONS...RADAR...
AND METEOROLOGICAL ANALYSIS.

BASED ON 1800 UTC SURFACE ANALYSIS AND SATELLITE IMAGERY THROUGH
2315 UTC.

...TROPICAL WAVES...
BROAD TROPICAL WAVE IS ALONG 40/41W S OF 17N MOVING W 10 TO 15
KT. WELL DEFINED INVERTED-V SHAPE ON SATELLITE IMAGERY.
SCATTERED MODERATE CONVECTION IS FROM 5N-12N BETWEEN 35W-46W.

WEAK TROPICAL WAVE IS ALONG 55W S OF 13N MOVING W 5-10 KT. THIS
WAVE REMAINS DIFFICULT TO LOCATE AND THE PSN IS MORE OR LESS
BASED ON CONTINUITY. WIDELY SCATTERED SHOWERS ARE ASSOCIATED
WITH THIS FEATURE. SCATTERED MODERATE CONVECTION IS ON THE SOUTH
END OF THE WAVE AXIS OVER NORTHERN SURINAME.

...THE ITCZ...
ITCZ AXIS IS CENTERED ALONG 11N15W 7N30W 9N38W 9N52W 9N60W.
CLUSTERS OF SCATTERED MODERATE CONVECTION ARE FROM 3N-8N BETWEEN
28W-35W.

...DISCUSSION...
GULF OF MEXICO...
DEEP LAYER TROUGH IS OVER THE SE U.S COVERING THE NORTHERN GULF
WATERS N OF 24N FROM FLORIDA TO NE MEXICO. AN UPPER HIGH IS OVER
TEXAS. NEARLY ZONAL FLOW DOMINATES THE REMAINDER OF THE GULF. AS
OF 2100 UTC...THE ATTENDANT COLD FRONT EXTENDS ACROSS WESTERN
BAHAMAS/CUBA AND THE YUCATAN PENINSULA INTO THE BAY OF CAMPECHE.
MOST OF THE CONVECTIVE ACTIVITY ASSOCIATED WITH THE FRONT IS
OVER THE W ATLC. AN AREA OF LOW CLOUDS WITH EMBEDDED SHOWERS IS
OVER THE SE PORTION OF THE GULF FROM 23N-25N BETWEEN 81W-86W.
BEHIND THE FRONT...A WEAK 1014 MB SURFACE HIGH IS NEAR 27N92W.
AND WILL MOVE TOWARD THE NE CORNER OF THE GULF LATE THURSDAY
ALLOWING THE SLY RETURN FLOW TO DEVELOP ACROSS THE WESTERN GULF.
THE SLY WINDS WILL INCREASE TO 15-20 KT LATE THURSDAY. WATER
VAPOR IMAGERY SHOWS VERY DRY MID TO UPPER AIR BEING ADVECTED
INTO THE GULF IN WAKE OF THE UPPER TROUGH OVER THE SE US. DEBRIS
MOISTURE FROM TD 19-E IS STREAMING ACROSS SOUTH-CENTRAL MEXICO
AND THE BAY OF CAMPECHE WITH WLY UPPER FLOW. THE NEXT COLD FRONT
WILL MOVE OFF THE TX COAST FRI NIGHT OR EARLY SAT.

CARIBBEAN SEA...
BROAD UPPER RIDGING CONTINUES TO DOMINATE THE BASIN WITH THE
UPPER HIGH LOCATED JUST SE OF THE DOMINICAN REPUBLIC. DRY/STABLE
MID TO UPPER AIR DOMINATES THE CARIBBEAN WATERS E OF 75W AND
NORTHERN VENEZUELA...SUPPRESSING CONVECTION ACROSS THIS AREA.
WIDELY SCATTERED MODERATE CONVECTION IS OVER THE SW CARIBBEAN
AND FROM NORTHERN COLOMBIA TO COSTA RICA DUE TO THE PRESENCE OF
THE ITCZ AXIS. AS OF 2100 UTC...A COLD FRONT CROSSES WESTERN
CUBA AND THE YUCATAN PENINSULA. A PREFRONTAL TROUGH LIES AHEAD
OF THE COLD FRONT AND EXTENDS FROM CENTRAL BAHAMAS/CUBA INTO THE
NW CARIBBEAN TO BELIZE WHERE THERE IS A SMALL AREA OF SHOWERS.
10-20KT TRADE WINDS BLOW ACROSS THE BASIN E OF 75W...CARRYING ON
PATCHES OF LOW LEVEL MOISTURE.

ATLANTIC OCEAN...
FRONTAL SYSTEM ASSOCIATED WITH DEEP LAYER TROUGHING OVER THE SE
US CONTINUES TO DOMINATE THE SW NORTH ATLC. AS OF 2100 UTC...THE
COLD FRONT ENTERS THE AREA NEAR 31N74W THEN CONTINUES SW ACROSS
THE NORTHERN BAHAMAS AND WESTERN CUBA INTO THE YUCATAN PENINSULA
AND THE BAY OF CAMPECHE. CLUSTERS OF MODERATE TO ISOLATED STRONG
CONVECTION ARE AHEAD OF A PREFRONTAL TROUGH THAT RUNS FROM
30N70W ACROSS THE CENTRAL BAHAMAS/CUBA INTO THE NW CARIBBEAN.
THIS CONVECTIVE ACTIVITY COVERS FROM 24N-31N BETWEEN 66W-72W.
UPPER DIFFLUENCE BETWEEN THE TROUGHING OVER THE SE US AND THE
RIDGING FROM THE CARIBBEAN IS ENHANCING THIS SHOWER/TSTM
ACTIVITY. GALE CONDITIONS ARE EXPECTED TO DEVELOP AHEAD OF THE
COLD FRONT N OF 28N TO 65W TONIGHT. THE PREFRONTAL TROUGH IS
FORECAST TO BECOME DIFFUSE TOMORROW AFTERNOON. THE REMAINDER OF
THE ATLC IS DOMINATED BY A HIGHLY AMPLIFIED RIDGE/TROUGH/RIDGE
PATTERN ALOFT. THE UPPER TROUGH IN THE CENTRAL ATLC HAS AN
ASSOCIATED OLD FRONTAL BOUNDARY ALONG 31N38W 24N48W 24N63W. A
BAND OF MAINLY LOW LEVEL CLOUDS WITH ISOLATED SHOWERS IS
ASSOCIATED WITH THE FRONT. NORTH OF THIS FRONT LIES A 1028MB SFC
HIGH NEAR 42N53W. A SURFACE RIDGE ALSO DOMINATES THE E ATLC E OF
30W.

$$
GR






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