[Tropical] Tropical Weather Discussion

[EMWIN Server]

AXNT20 KNHC 081138
TWDAT

TROPICAL WEATHER DISCUSSION
NWS TPC/NATIONAL HURRICANE CENTER MIAMI FL
705 AM EST THU DEC 07 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 4N10W 3N20W 4N30W 4N40W 3N51W.
SCATTERED MODERATE/ISOLATED STRONG CONVECTION IS SEEN WITHIN 30
NM ON EITHER SIDE OF THE AXIS BETWEEN 38W-43W AND BETWEEN
46W-48W.

...DISCUSSION...
THE GULF OF MEXICO...
WLY UPPER LEVEL FLOW IS CARRYING ABUNDANT MOISTURE AND HIGH
CLOUDS E ACROSS MUCH OF THE GULF EARLY THIS MORNING. SATELLITE
DERIVED WINDS INDICATED CORE SPEEDS OF 60-80 KT OVER THE AREA. A
DEEP LAYER TROUGH IS AMPLIFYING ACROSS THE EASTERN U.S. AND THE
NORTHERN GULF WATERS. AS OF 0900 UTC...THE ATTENDANT COLD FRONT
EXTENDS ACROSS WESTERN CUBA AND THE YUCATAN PENINSULA INTO THE
BAY OF CAMPECHE. A LINE OF SHOWERS WITH EMBEDDED TSTMS IS JUST
SE OF THE FLORIDA KEYS AND SE FLORIDA ASSOCIATED WITH THE FRONT.
THIS FRONTAL BOUNDARY IS GENERALLY AT THE LEADING EDGE OF A
STRONG 1042 MB SFC HIGH BUILDING INTO THE NRN GULF FROM KANSAS.
STRONG N-NE WINDS ARE BLOWING BEHIND THE FRONT. EARLIER QUIKSCAT
PASS INDICATED WIND SPEEDS OF 25 TO 35 KT. A GALE WARNING IS IN
EFFECT FOR THE WRN GULF FROM 22N TO 25N W OF 94W AND FROM 25N TO
28N W OF 90W...WITH RAPIDLY INCREASING NE WINDS AND WIND WAVES.
THESE CONDITIONS WILL GRADUALLY SUBSIDE THROUGH THE WEEKEND AS
THE HIGH WEAKENS AND SHIFTS E. BASED ON SFC DATA AND THE
QUIKSCAT PASS...THE SFC TROUGH THAT WAS PREVIOUSLY ALONG THE
WESTERN GULF WAS REMOVED FROM THE 06Z SFC CHART. THE BROWNSVILLE
DOPPLER RADAR IS STILL SHOWING PATCHES OF LIGHT RAIN IN THE
AREA...AFFECTING THE DEEP SOUTH AND NE MEXICO...INCLUDING THE
CITIES OF MONTERREY...SALTILLO AND MONCLOVA. NIGHT CHANNEL VIS
IMAGES SHOW COLD STRATOCUMULUS CLOUDS OVER THE GULF. THE GFS
MODEL SUGGESTS THAT MOST OF THE PRECIP WILL BE CONFINED TO THE
WRN GULF/COASTAL MEXICO INCLUDING THE BAY OF CAMPECHE FRI
THROUGH SATURDAY.

CARIBBEAN SEA...
DRY MID TO UPPER AIR CONTINUES TO DOMINATE MUCH OF THE CARIBBEAN
SEA EARLY THIS MORNING. A SHORT WAVE TROUGH REMAINS ALONG
79W/80W. A SFC TROUGH HAS DEVELOPED OVER THE SAME AREA
GENERATING SCATTERED SHOWERS AND ISOLATED TSTMS. COMPUTER MODEL
SUGGESTS THAT THIS SHOWER ACTIVITY WILL MOVE WWD TOWARD
NICARAGUA AND HONDURAS DURING THE NEXT 12-24 HOURS. AN UPPER
RIDGE EXTENDS FROM THE SW PORTION OF THE BASIN THROUGH
HISPANIOLA INTO THE W-CENTRAL ATLC. A WEAKENING UPPER TROUGH
ENTERS THE EASTERN CARIBBEAN NEAR GUADELOUPE FROM THE TROPICAL
NORTH ATLC. THE TRADE WINDS ARE CARRYING PATCHES OF LOW LEVEL
MOISTURE WITH LIGHT SHOWERS ACROSS THE BASIN. ONE OF THEM IS
APPROACHING THE ABC ISLANDS. A DIFFLUENT PATTERN ALOFT IS
SUPPORTING THE DEVELOPMENT OF SMALL AREA OF SHOWERS/ISOLATED
TSTMS OVER THE GULF OF HONDURAS AND IS ALSO ENHANCING THE
CONVECTIVE ACTIVITY ASSOCIATED WITH THE SFC TROUGH. THE QUIKSCAT
PASS SHOWED THE TRADES IN THE 15 TO 25 KT RANGE...WITH THE
STRONGEST WINDS OFF THE COLOMBIAN COAST. THE STRONG COLD FRONT
MENTIONED ABOVE IS ENTERING THE NW CARIBBEAN. NE FLOW ARE
EXPECTED TO INCREASE OVER THE NW PORTION OF THE CARIBBEAN FRI
EVENING INTO SAT AS STRONGER
HIGH PRESSURE BUILDS N OF THE AREA.

THE ATLANTIC OCEAN...
A COLD FRONT IS MOVING ACROSS THE SW NORTH ATLC AND THE NORTHERN
BAHAMAS. STRONG HIGH PRESSURE WILL BUILD INTO THE AREA BEHIND
THE FRONT FRIDAY AND SATURDAY...ALLOWING NE WINDS AND WIND WAVES
TO INCREASE. A GALE WARNING IS ALREADY IN EFFECT BEHIND THE
FRONT W OF 75W. A PRE-FRONTAL TROUGH RUNS FROM 31N70W TO 23N73W.
SCATTERED MODERATE/ISOLATED STRONG CONVECTION IS AHEAD OF THE
TROUGH FROM 25N-31N BETWEEN 64W-68W. DIFFLUENCE BETWEEN THE DEEP
LAYERED TROUGH OVER THE ERN U.S. AND THE UPPER RIDGE EXTENDING
NE THROUGH HISPANIOLA INTO THE W-CENTRAL ATLC IS ENHANCING THIS
CONVECTIVE ACTIVITY. A PRONOUNCED UPPER LOW IS SEEN SPINNING
NEAR 19N36W. ABUNDANT UPPER LEVEL MOISTURE IS ON THE SE
SEMICIRCLE OF THIS FEATURE...WITH SCATTERED SHOWERS POSSIBLE
FROM 13N-22N EAST OF 30W. A STRONG 1038 MB SFC HIGH PRES LOCATED
NORTH OF THE AREA DOMINATES THE E AND CENTRAL ATLC. PATCHES OF
LOW LEVEL MOISTURE ARE SEEN UNDER THE INFLUENCE OF THIS SYSTEM
OVER THE OCEAN. WLY JET OVER THE DEEP TROPICS CONTINUES TO SHEAR
THE CONVECTION OVER THE ITCZ TO THE E.

$$
GR





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