[Tropical] Tropical Weather Discussion

[EMWIN Server]

AXNT20 KNHC 071148
TWDAT

TROPICAL WEATHER DISCUSSION
NWS NATIONAL HURRICANE CENTER MIAMI FL
705 AM EST FRI DEC 07 2012

TROPICAL WEATHER DISCUSSION FOR NORTH AMERICA...CENTRAL
AMERICA...GULF OF MEXICO...CARIBBEAN SEA...NORTHERN 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 0600 UTC SURFACE ANALYSIS AND SATELLITE IMAGERY THROUGH
1115 UTC.

...ITCZ/MONSOON TROUGH...

THE MONSOON TROUGH EXTENDS ACROSS W AFRICA TO THE COAST OF
GUINEA. THE ITCZ BEGINS AT THE COAST NEAR 9N14W AND CONTINUES
ALONG 6N27W 7N42W TO SOUTH AMERICA NEAR 5N54W. SCATTERED
MODERATE/ISOLATED STRONG CONVECTION IS FROM 5N-8N BETWEEN
43W-46W. SCATTERED MODERATE CONVECTION IS FROM 9N-11N BETWEEN
38W-40W. CLUSTERS OF ISOLATED MODERATE CONVECTION DOT THE AREA N
OF 2N TO THE ITCZ BETWEEN 15W-35W. A SURFACE TROUGH IS JUST N OF
THE ITCZ EXTENDING ALONG 46W BETWEEN 9N-14N WITH SCATTERED
MODERATE/ISOLATED STRONG CONVECTION FROM 10N-13N BETWEEN
45W-48W.

...DISCUSSION...

GULF OF MEXICO...
AN UPPER RIDGE EXTENDS FROM ACROSS MEXICO TO OVER THE
MISSISSIPPI VALLEY AND COUPLED WITH THE UPPER TROUGH THAT
EXTENDS JUST E OF THE FLORIDA PENINSULA IS GIVING THE GULF
MOSTLY NW FLOW ALOFT. A SURFACE TROUGH AT 07/0900 UTC EXTENDS
FROM 29N91W SE TO 24N86W. ISOLATED SHOWERS DOT AREA WITHIN 200
NM NE OF THE TROUGH. AN AREA OF LOW CLOUDS WITH POSSIBLE
ISOLATED SHOWERS AND POSSIBLE PATCHES OF FOG COVERS THE FAR NE
GULF N OF TAMPA E OF PANAMA CITY. THIS IS LEAVING THE REMAINDER
OF THE GULF UNDER CLEAR SKIES THIS MORNING. SURFACE TROUGH WILL
DISSIPATE LATER TODAY. HIGH PRESSURE WILL BUILD NE OF THE REGION
THROUGH THE WEEKEND. A STRONG COLD FRONT WILL MOVE OFF THE TEXAS
COAST MON MORNING AND REACH FROM MOBILE BAY TO TAMPICO BY MON
EVENING THEN REACH FROM BIG BEND REGION TO W BAY OF CAMPECHE TUE.

CARIBBEAN SEA...
A BROAD UPPER RIDGE IN THE TROPICAL ATLC EXTENDS A RIDGE AXIS
ACROSS THE S CARIBBEAN THROUGH 11N62W TO OVER CENTRAL AMERICA
NEAR 13N84W GIVING THE CARIBBEAN MAINLY SW TO W FLOW ALOFT. A
SURFACE TROUGH IS OVER THE W CARIBBEAN EXTENDING FROM 21N81W
ACROSS THE CAYMAN ISLANDS TO 13N77W. REMNANT MOISTURE ACROSS THE
N CARIBBEAN IS GENERATING SCATTERED SHOWERS AND POSSIBLE
ISOLATED THUNDERSTORMS N OF LINE FROM 15N66W TO 16N77W AND
WITHIN 75 NM OF LINE FROM 17N79W TO OVER COSTA RICA AND W PANAMA
NEAR 10N83W. WEAK SURFACE RIDGE OVER THE W ATLC WILL SHIFT E AND
GRADUALLY WEAKEN TODAY MAINTAINING LIGHT TO MODERATE WINDS
ACROSS MOST OF THE REGION.

ATLANTIC OCEAN...
AN UPPER TROUGH EXTENDS E OF THE FLORIDA PENINSULA THROUGH
32N79W TO CUBA NEAR 22N78W. THE SURFACE TROUGH EXTENDS FROM
31N80W OVER E FLORIDA FROM MELBOURNE ALONG THE E COAST OF LAKE
OKEECHOBEE AND ACROSS THE UPPER FLORIDA KEYS TO 24N81W. THE
SURFACE TROUGH AND UPPER TROUGH ARE INTERACTING AND GENERATING
SCATTERED SHOWERS/THUNDERSTORMS N OF 28N BETWEEN 77W-80W WITH
SCATTERED SHOWERS AND POSSIBLE ISOLATED THUNDERSTORMS N OF 26N W
OF 74W. AN UPPER RIDGE EXTENDS FROM NEAR 20N64W TO BEYOND 32N70W
PROVIDING DIFFLUENCE ALOFT TO GENERATE SCATTERED SHOWERS/
ISOLATED THUNDERSTORMS FROM 20N-26N BETWEEN 70W-78W. AN UPPER
TROUGH N OF THE DISCUSSION AREA IS DRAPING A COLD FRONT INTO THE
W CENTRAL ATLC NEAR 32N55W TO 31N58W WHERE IT BECOMES STATIONARY
TO 31N77W. BROAD UPPER TROUGH COVERS THE E/CENTRAL ATLC N OF 20N
BETWEEN 30W-50W SUPPORTING COLD FRONT THAT EXTENDS THROUGH
32N32W ALONG 22N38W TO 16N46W THEN DISSIPATES TO 14N55W. AN
UPPER RIDGE IS JUST TO THE E EXTENDING FROM THE TROPICAL ATLC
NEAR 14N31W TO BEYOND 32N20W ENHANCING SCATTERED SHOWERS/
ISOLATED THUNDERSTORMS WITHIN 200 NM E OF THE FRONT N OF 19N.
SURFACE RIDGE DOMINATES THE FAR E ATLC N OF 18N E OF 27W
ANCHORED BY A 1023 MB HIGH JUST N OF THE CANARY ISLANDS.
WEAKENING SURFACE RIDGE WILL SHIFT E AND GRADUALLY WEAKEN TODAY
ALLOWING A COLD FRONT TO BRUSH PAST THE NORTHERN WATERS. SURFACE
TROUGH OVER FLORIDA WILL DRIFT IN W-NW THROUGH TODAY. STRONG
HIGH PRESSURE WILL BUILD NE OF THE AREA FRI THROUGH SUN. A NEW
COLD FRONT WILL APPROACH NW WATERS TUE.

FOR ADDITIONAL INFORMATION PLEASE VISIT
HTTP://WWW.HURRICANES.GOV/MARINE

$$
PAW






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