[Tropical] Tropical Weather Discussion

[EMWIN Server]

AXNT20 KNHC 281727
TWDAT

TROPICAL WEATHER DISCUSSION
NWS TPC/NATIONAL HURRICANE CENTER MIAMI FL
105 PM EST TUE 28 DEC 2004

TROPICAL WEATHER DISCUSSION FOR NORTH AMERICA...CENTRAL
AMERICA...GULF OF MEXICO...CARIBBEAN SEA...NORTHEASTERN
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 1200 UTC SURFACE ANALYSIS AND SATELLITE IMAGERY THROUGH
1645 UTC.

...ITCZ...

ITCZ AXIS IS CENTERED ALONG 9N10W 5N30W 5N50W 6N65W BECOMING
ILL-DEFINED OVER THE REMAINDER OF S AMERICA. SCATTERED
MODERATE/ISOLATED STRONG CONVECTION FROM 3N-9N BETWEEN 30W-45W.
WIDELY SCATTERED MODERATE CONVECTION OVER S AMERICA FROM THE
EQUATOR TO 7N BETWEEN 48W-60W.

...DISCUSSION...

GULF OF MEXICO...
MIDDLE TO UPPER LEVEL RIDGING IS BUILDING ACROSS MEXICO AND THE
GLFMEX LEADING TO STRONG SUBSIDENCE AND TRANQUIL WEATHER.  THIS
PATTERN IS EXPECTED TO REMAIN ESSENTIALLY UNCHANGED FOR THE NEXT
SEVERAL DAYS KEEPING UPSTREAM DISTURBANCES AND COLD FRONTS
CONFINED N OF THE AREA.  AT THE LOWER LEVELS...A STRONG PRESSURE
GRADIENT REMAINS OVER THE AREA COURTESY OF A 1040 MB HIGH OVER
THE E UNITED STATES. ASSOCIATED NE FLOW IS ADVECTING A LARGE
FIELD OF LOWER TO MIDDLE LEVEL STRATOCUMULUS CLOUDS FROM THE
ATLANTIC WATERS ACROSS THE S HALF OF FLORIDA. SURFACE HIGH
PRESSURE
WILL SHIFT SLOWLY SEWD TOWARD BERMUDA DURING THE NEXT 2 DAYS
PRODUCING MODERATE ELY FLOW AND A SLOW WARMING TREND. THE
STRONGEST WINDS WILL OCCUR OVER THE STRAITS OF FLORIDA WITH SOME
WEAK RETURN FLOW DEVELOPING OVER THE FAR W GLFMEX TOMORROW.

CARIBBEAN...
A MIDDLE TO UPPER LEVEL TROUGH OVER THE W ATLC WATERS TRAILS SWD
OVER W CUBA TO THE YUCATAN PENINSULA.  ATTENDANT COLD FRONT
PULLS UP STATIONARY OVER HISPANIOLA EXTENDING SW ALONG 15N80W TO
COSTA RICA.  BROKEN/OVERCAST CLOUDINESS AND SCATTERED
SHOWERS/THUNDERSTORMS ARE WITHIN 100 NM SE OF FRONT AND 300 NM
NW OF FRONT.  ELSEWHERE W OF FRONT...NLY FLOW IS PRODUCING
OVERCAST CLOUDINESS AND SCATTERED SHOWERS ALONG THE WINDWARD
FACING SLOPES OF HONDURAS...GUATEMALA...AND COSTA RICA.  THE S
EXTENT OF THE FRONTAL BOUNDARY WILL SLOWLY DRIFT WESTWARD OVER
THE NEXT 24 HOURS PRODUCING INCREASING CLOUDINESS AND SHOWERS
OVER CENTRAL AMERICA.  OVER THE E HALF OF THE CARIBBEAN...MIDDLE
TO UPPER LEVEL RIDGING IS PRODUCING STRONG SUBSIDENCE AND VERY
DRY/STABLE CONDITIONS ABOVE 800 HPA.  A SMALL AREA OF LOWER
LEVEL MOISTURE OVER THE S CARIBBEAN IS PRODUCING SCATTERED
SHOWERS FROM 12N-15N BETWEEN 62W-75W INCLUDING THE ABC ISLANDS.

ATLANTIC OCEAN...
A PROGRESSIVE MIDDLE TO UPPER LEVEL TROUGH IS MOVING QUICKLY
OVER THE W ATLC WATERS EXTENDING FROM JUST E OF BERMUDA TO THE N
BAHAMAS.  ATTENDANT COLD FRONT ENTERS THE AREA ALONG 32N54W
EXTENDING SW TO HISPANIOLA. A NARROW...150-200 NM WIDE...BAND OF
SCATTERED SHOWERS EXIST ALONG AND NW OF THE BOUNDARY.  STRONG
SUBSIDENCE AND MIDDLE TO UPPER LEVEL DRY/STABLE CONDITIONS EXIST
ELSEWHERE W OF THE FRONT EXTENDING ALL THE WAY TO FLORIDA.
HOWEVER...COLD AIR ADVECTION OVER THE RELATIVELY WARM OCEAN
WATERS IS PRODUCING A LARGE FIELD OVER BROKEN/OVERCAST
STRATOCUMULUS CLOUDS.  SHIFTING EWD...A HIGH OVER LOW TYPE
PATTERN EXIST OVER THE CENTRAL AND E ATLC WITH A MIDDLE TO UPPER
LEVEL HIGH NEAR THE AZORES AND A LARGE DEEP LAYERED LOW NEAR
21N45W.  THIS SYSTEM HAS WORKED DOWN TO THE SURFACE WITH A 1009
MB LOW NEAR 23N50W.  DIFFLUENT UPPER LEVEL FLOW NEAR AND TO THE
EAST OF THE DEEP LAYERED LOW IS PRODUCING A LARGE AREA OF
CLOUDINESS AND SCATTERED SHOWERS/THUNDERSTORMS FROM 20N-26N
BETWEEN 35W-46W.  THE DEEPEST CONVECTION WITHIN THIS AREA IS
CONCENTRATED FROM 21N-24N BETWEEN 40W-45W.  SIMILAR ACTIVITY IS
OBSERVED WITHIN THE ITCZ FROM 30W-45W. STRONG SUBSIDENCE EXIST
OVER THE CONFLUENT SIDE OF THE DEEP LAYERED LOW EXTENDING INTO
THE E CARIBBEAN.  ELSEWHERE OVER THE E ATLC...STRONG SUBTROPICAL
RIDGE EXTENDS FROM THE AZORES SW TO 15N40W.  ASSOCIATED PRES
GRADIENT IS PRODUCING MODERATE TO STRONG ELY FLOW OVER A GOOD
PORTION OF THE E ATLC.

$$
RHOME


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