[Tropical] Tropical Weather Discussion

[EMWIN Server]

AXNT20 KNHC 080543
TWDAT

TROPICAL WEATHER DISCUSSION
NWS TPC/NATIONAL HURRICANE CENTER MIAMI FL
105 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 0000 UTC SURFACE ANALYSIS AND SATELLITE IMAGERY THROUGH
0515 UTC.

...THE ITCZ...
ITCZ AXIS IS CENTERED ALONG 5N10W 4N20W 5N30W 4N40W 4N51W.
SCATTERED MODERATE/ISOLATED STRONG CONVECTION IS SEEN WITHIN
60 NM ON EITHER SIDE OF THE AXIS BETWEEN 33W-46W.

...DISCUSSION...
THE GULF OF MEXICO...
ZONAL UPPER FLOW IS CARRYING ABUNDANT UPPER MOISTURE AND HIGH
CLOUDS E ACROSS MUCH OF THE GULF TONIGHT. SATELLITE DERIVED
WINDS INDICATED CORE SPEEDS OF 70-90 KT OVER THE AREA. A DEEP
LAYER TROUGH IS AMPLIFYING ACROSS THE EASTERN U.S. AND THE
NORTHERN GULF WATERS. AS OF 0300 UTC...THE ATTENDANT COLD FRONT
EXTENDS FROM SOUTH FLORIDA TO THE YUCATAN PENINSULA. THIS FRONTAL
BOUNDARY IS GENERALLY AT THE LEADING EDGE OF A STRONG 1044 MB
SFC HIGH BUILDING INTO THE NRN GULF FROM THE CENTRAL U.S..STRONG
NELY WINDS ARE BLOWING BEHIND THE FRONT. A GALE WARNING IS IN
EFFECT FOR THE WRN GULF N OF 25N W OF 85W...WITH RAPIDLY
INCREASING NE WINDS AND WIND WAVES. THESE CONDITIONS WILL
GRADUALLY SUBSIDE THROUGH THE WEEKEND AS THE HIGH WEAKENS AND
SHIFTS E. A SFC TROUGH HAS DEVELOPED ACROSS THE WESTERN GULF
ALONG 26N96W 20N94W. THE BROWNSVILLE DOPPLER RADAR IS SHOWING A
FAIRLY WIDESPREAD REGION OF LIGHT RAIN IN THE AREA...AFFECTING
THE DEEP SOUTH AND NE MEXICO. 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
TONIGHT. THE LARGE SCALE UPPER PATTERN OVER THE CARIBBEAN IS
DOMINATED BY A SHORT WAVE TROUGH ALONG 80W AND AN UPPER RIDGE
WITH THE AXIS EXTENDING FROM THE SW PORTION OF THE BASIN THROUGH
HISPANIOLA. A WEAK UPPER TROUGH CONTINUES TO EXTEND THROUGH THE
LEEWARD ISLANDS INTO THE NE CARIBBEAN. THE SHORT WAVE TROUGH IS
GENERATING SCATTERED SHOWERS FROM 12N-19N BETWEEN 77W-81W.
PATCHES OF LOW LEVEL MOISTURE WITH LIGHT SHOWERS ARE EMBEDDED IN
THE TRADE WINDS MAINLY ACROSS THE E CARIBBEAN. A DIFFLUENT
PATTERN ALOFT IS SUPPORTING THE DEVELOPMENT OF SMALL AREA OF
SHOWERS/ISOLATED TSTMS OVER THE GULF OF HONDURAS. EARLIER
QUIKSCAT PASS SHOWED THE TRADES IN THE 15 TO 25 KT RANGE. STRONG
COLD FRONT WILL ENTER THE NW CARIB EARLY THIS MORNING WITH GUSTY
N WINDS. NE FLOW ARE EXPECTED TO INCREASE OVER THE NW PORTION
FRI EVENING INTO SAT AS STRONGER HIGH PRESSURE BUILDS N OF THE
AREA.

THE ATLANTIC OCEAN...
A COLD FRONT IS PUSHING INTO THE SW NORTH ATLC JUST OFF THE
COAST OF NE FLORIDA. 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 77W. A PRE-FRONTAL TROUGH GOES FROM 31N70W
TO 23N75W. SCATTERED MODERATE/ISOLATED STRONG CONVECTION IS
WITHIN 70-100 NM AHEAD OF THE TROUGH. A DIFFLUENT PATTERN ALOFT
BETWEEN THE DEEP LAYERED TROUGH OVER THE ERN U.S. AND THE UPPER
RIDGE EXTENDING NE THROUGH HISPANIOLA INTO THE CENTRAL ATLC IS
ENHANCING THIS CONVECTIVE ACTIVITY. A PRONOUNCED UPPER LOW IS
SEEN SPINNING NEAR 19N35W. ABUNDANT UPPER LEVEL MOISTURE IS ON
THE SE SEMICIRCLE OF THIS FEATURE...WITH SCATTERED SHOWERS
POSSIBLE FROM 12N-20N EAST OF 30W. A STRONG 1039 MB SFC HIGH PRES
LOCATED NEAR 41N40W 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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