[Tropical] Tropical Weather Discussion

[EMWIN Server]

AXNT20 KNHC 091744
TWDAT

TROPICAL WEATHER DISCUSSION
NWS TPC/NATIONAL HURRICANE CENTER MIAMI FL
105 PM EST TUE JAN 09 2007

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 1200 UTC SURFACE ANALYSIS AND SATELLITE IMAGERY THROUGH
1715 UTC.

...THE ITCZ...
ITCZ AXIS IS ALONG 2N AT THE PRIME MERIDIAN...3N16W 2N30W 3N45W
2N51W. WIDELY SCATTERED MODERATE CONVECTION IS FROM 1N-6N
BETWEEN 30W-60W. A CLUSTER OF MODERATE TO ISOLATED STRONG
CONVECTION IS NEAR 1S37W.

...DISCUSSION...
GULF OF MEXICO...
DEEP LAYERED TROUGH REMAINS OVER THE E US AND THE NE GULF MOVING
INTO THE NW ATLC RESULTING IN MOSTLY WESTERLY UPPER WINDS ACROSS
THE GULF. THESE WINDS ARE TRANSPORTING ABUNDANT UPPER LEVEL
MOISTURE ACROSS THE GULF MAINLY NORTH OF 25N. AS OF 1500 UTC...
THE ATTENDANT COLD FRONT IS SE OF THE AREA OVER WESTERN CUBA.
COLD STRATOCUMULUS CLOUDS COVER THE GULF...PARTICULARLY SOUTH
OF 25N INCLUDING THE BAY OF CAMPECHE. BROKEN TO OVERCAST LOW
CLOUDS ARE POOLED AGAINST THE SIERRA MADRE DEL SUR IN MEXICO.
MODERATE TO STRONG NORTH WINDS WITH COOLER TEMPERATURES AND LOW
DEW POINTS ARE FOUND BEHIND THE FRONTAL BOUNDARY. A SURFACE
RIDGE CONTINUES TO BUILD ACROSS THE GULF AND NE MEXICO WITH A
1035 MB HIGH ALONG THE TEXAS/MEXICO BORDER. MODERATE/STRONG
NORTHERLY SURFACE WINDS WILL REMAIN ACROSS THE GULF THROUGH
TONIGHT BECOMING WEAKER AND MORE EASTERLY AS THE SURFACE RIDGE
GRADUALLY MOVES E ACROSS THE SE US. HIGH PRES WILL REMAIN IN
CONTROL OF THE WEATHER PATTERN ACROSS THE GULF THROUGH AT LEAST
FRIDAY. ON THIS DAY...SLY RETURN FLOW WILL DEVELOP AHEAD OF THE
NEXT COLD FRONT.

CARIBBEAN SEA...
NARROW UPPER RIDGE EXTENDS FROM CENTRAL AMERICA NE TO OVER W
CUBA/THE BAHAMAS. ANOTHER UPPER LEVEL RIDGE EXTENDING FROM A
HIGH ANCHORED OVER NE BRAZIL COVERS COLOMBIA...VENEZUELA AND THE
SE CORNER OF THE BASIN. IN BETWEEN...THERE IS AN UPPER TROUGH
THAT RUNS FROM HISPANIOLA TO COSTA RICA. STRONG SUBSIDENCE AND
VERY DRY AIR REMAIN IN CONTROL OF THE CARIBBEAN. EASTERLY TRADE
WINDS HAVE WEAKEN AS THE HIGH PRESSURE OVER THE ATLC CONTINUES
TO SHIFT E AHEAD OF THE COLD FRONT THAT REACHED WESTERN CUBA
THIS MORNING. THE CITY OF HAVANA REPORTED NLY WINDS OF AROUND 15
KT. LATEST SAT PICTURES SHOWS THAT THE LEADING EDGE OF THE
FRONTAL BOUNDARY IS ACROSS THE ANDROS ISLAND IN THE BAHAMAS AND
WESTERN CUBA CONTINUING MAINLY S ALONG THE YUCATAN CHANNEL/
PENINSULA AND BELIZE. SHOWERS AND POSSIBLE ISOLATED
THUNDERSTORMS CAN BE EXPECTED WITH THE PASSAGE OF THE FRONT. THE
TRADE WINDS ARE EXPECTED TO INCREASE AGAIN THU THROUGH SAT AS
HIGH PRES BUILD N OF AREA AND MOVES E.

ATLANTIC OCEAN...
DEEP LAYERED TROUGH OVER THE US AND NE GULF OF MEXICO EXTENDS
OVER THE FAR W ATLC. THE ASSOCIATED COLD FRONT ENTERS THE AREA
NEAR 32N70W...THEN CONTINUES SWWD ACROSS THE NORTHERN BAHAMAS
AND W CUBA. DOPPLER RADAR DEPICTS SCATTERED SHOWERS/ISOLATED
THUNDERSTORMS OVER THE STRAITS OF FLORIDA ASSOCIATED WITH THE
FRONTAL BOUNDARY. NARROW UPPER RIDGE IS IN THE W ATLC EXTENDING
FROM ACROSS W CUBA TO NEAR 28N67W. STRONG SUBSIDENCE AND DRY AIR
DOMINATES THE REMAINDER OF THE W ATLC W OF 60W. AN UPPER LOW
REMAINS NEAR 22N60W WITH A TROUGH EXTENDING E AND NE TO NEAR THE
CANARY ISLANDS. WEAK SURFACE REFLECTION IN THE FORM OF A SURFACE
TROUGH ALSO REMAINS OVER THE ATLC AND EXTENDS FROM 26N54W TO THE
VIRGIN ISLANDS NEAR 19N64W. SCATTERED SHOWERS/ISOLATED
THUNDERSTORMS ARE ON THE NORTHERN END OF THE TROUGH. A BROAD
HIGH AMPLITUDE UPPER RIDGE CONTINUES TO DOMINATE THE TROPICS
WITH THE RIDGE AXIS EXTENDING N TO 23N40W COVERING THE AREA
BETWEEN THE LESSER ANTILLES AND THE COAST OF W AFRICA. JET
STREAM WITH WINDS OF 90 TO 110 KT EXTENDS ALONG THE N PERIPHERY
OF THIS UPPER RIDGE. AT THE SURFACE...HIGH PRESSURE DOMINATES
THE ENTIRE ATLC E OF THE FRONT IN THE FAR W ATLC WITH AN
ADDITIONAL WEAKNESS ALONG THE SURFACE TROUGH MENTIONED ABOVE. A
1031 MB HIGH IS OVER THE CENTRAL ATLC NEAR 36N42W.

$$
GR






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