[Tropical] Tropical Weather Discussion

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AXNT20 KNHC 030538
TWDAT

TROPICAL WEATHER DISCUSSION
NWS TPC/NATIONAL HURRICANE CENTER MIAMI FL
105 AM EST THU 03 FEB 2005

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 0000 UTC SURFACE ANALYSIS AND SATELLITE IMAGERY THROUGH
0445 UTC.

...ITCZ...

ITCZ AXIS IS CENTERED ALONG 9N10W 3N18W 3N35W 2N52W. CLUSTERS OF
SCATTERED MODERATE/ISOLATED STRONG CONVECTION ARE S OF 5N
BETWEEN 20W-45W.

...DISCUSSION...

GULF OF MEXICO...
WEAK 1016 MB LOW OVER S MISSISSIPPI AND ASSOCIATED FRONTAL
SYSTEM CONTINUE TO BE THE MAIN WEATHER MAKER WITH A SWATH OF
RAIN AFFECTING THE E UNITED STATES FROM S GEORGIA AND ALABAMA
AND AS FAR NORTH THE E GREAT LAKES. SCATTERED SHOWERS ARE
AFFECTING THE N GULF COAST N OF 27N FROM THE FLORIDA PENINSULA
TO ALABAMA. THE FRONTAL SYSTEM CONSISTS OF A WARM FRONT
EXTENDING FROM THE COAST OF FLORIDA NEAR 29N83W TO THE 1016 MB
LOW NEAR 30N88W AND A COLD FRONT EXTENDING S TO THE BAY OF
CAMPECHE AND THE COAST OF MEXICO NEAR 18N93W. SHOWERS AND
THUNDERSTORMS ARE MOSTLY N OF THE WARM FRONT. A STATIONARY FRONT
IS BACKED AGAINST THE E SLOPES OF THE SIERRA MADRE MOUNTAINS.
OVERCAST CLOUDINESS AND ISOLATED SHOWERS EXISTS BEHIND THE COLD
FRONT IN THE RELATIVELY UNSTABLE ENVIRONMENT CREATED BY COLD
ADVECTION OVER A WARM SEA SURFACE WITH PACIFIC MOISTURE ADDING
TO THE MIX. THE PATTERN ALOFT CONTINUES TO SLOWLY SHARPEN AS A
SECOND MID/UPPER TROUGH IN AS MANY DAYS...OVER THE SW UNITED
STATES AND NW MEXICO AMPLIFIES S AND MID/UPPER LEVEL RIDGING
OVER THE GULF NOSES TO NORTH. THIS EVOLUTION SHOULD PRODUCE
WEAKENING UPPER LEVEL DYNAMICS/LIFT TONIGHT WHILE THE LOW AND
ATTENDANT WARM FRONT MOVE JUST N OF THE AREA LATER THIS MORNING.
HOWEVER...LOW LEVEL MOISTURE POOLING WILL CONTINUE TO GENERATE A
NARROW BAND OF SCATTERED SHOWERS ALONG THE COLD FRONT AS IT
MOVES ACROSS FLORIDA TODAY CLEARING THE S TIP BY EARLY FRI.

CARIBBEAN...
MID/UPPER RIDGE REMAINS OVER THE W HALF OF THE CARIBBEAN
ANCHORED BY A HIGH OVER CENTRAL AMERICA NEAR NICARAGUA/HONDURAS
BORDER. OVER THE NE CARIBBEAN...WEAK TROUGHING HAS DEVELOPED AS
A DEEP LAYERED TROUGH OVER THE W ATLC AMPLIFIES AND DIPS S. THE
RESULTING UPPER FLOW OVER THE CARIBBEAN IS PRIMARILY FROM THE NW
WITH VIRTUALLY ALL UPSTREAM MOISTURE STREAMING N OF THE AREA
ACROSS THE GULF AND LEAVING THE CARIBBEAN UNDER STRONG
SUBSIDENCE AND DRY/STABLE CONDITIONS ALOFT. THE LOW LEVELS ARE
ALSO RELATIVELY DRY AS POST-FRONTAL N FLOW BEHIND THE W ATLC
FRONT FILTERS S FROM THE LEEWARD ISLANDS JUST N OF GUADELOUPE TO
16N67W. LINE OF BROKEN LOW CLOUDS AND ISOLATED SHOWERS ARE
WITHIN 120 NM S OF THE FRONT. A FEW SHOWERS ARE ALSO NOTED ALONG
THE COAST OF S AMERICA E OF 73W. ADDITIONALLY...THE USUAL AREA
OF OVERCAST LOW CLOUDS WITH ISOLATED SHOWERS IS NOTED INLAND
OVER PORTIONS OF CENTRAL AMERICA N OF W PANAMA AS NE FLOW
ENCOUNTERS WINDWARD FACING SLOPES OF THE INLAND MOUNTAINS.

ATLANTIC WEST OF 45W...
A NEARLY STATIONARY DEEP-LAYERED LOW IS LOCATED ROUGHLY 400 NM
ESE OF BERMUDA WITH A DEEPENING 991 MB STORM FORCE LOW CENTERED
NEAR 31N59W. ASSOCIATED OCCLUDED FRONT EXTENDS WELL TO E NEAR
32N47W WITH COLD FRONT TRAILING S ALONG 25N47W THEN SW 20N53W TO
THE LEEWARD ISLANDS NEAR 17N62W THEN WEAKENING E INTO THE
CARIBBEAN. A NARROW 60 NM WIDE BAND OF SCATTERED SHOWERS
ACCOMPANIES A WEAK LOW LEVEL TROUGH TO THE E OF THE FRONT FROM
21N46W TO 26N42W. BROKEN STRATOCUMULUS FIELD IS NOTED W OF THE
FRONT ACROSS THE BAHAMAS TO THE GREATER ANTILLES AND FLORIDA. A
SURFACE TROUGH IS ALONG THE E COAST OF FLORIDA FROM 27N80W TO
31N81W WHERE A BAND OF OVERCAST LOW CLOUDS WITH SCATTERED
SHOWERS EXISTS. WHILE THE STRONGEST DYNAMICS/LIFT WITH THIS
PATTERN IS CONFINED N OF THE AREA...INSTABILITY ASSOCIATED WITH
THE COLD CORE UPPER LOW IS PRODUCING SCATTERED CELLS OF
SCATTERED SHOWERS/ISOLATED THUNDERSTORMS N OF 27N BETWEEN
50W-65W.  WATER VAPOR IMAGERY INDICATES THE MID/UPPER LEVEL
TROUGH IS DEEPENING AS A SHORTWAVE FEATURE SWINGS THROUGH THE
BASE. THIS SHOULD SUPPORT SOME ADDITIONAL STRENGTHENING OF THE
SURFACE LOW OVER THE NEXT 24 HOURS AS IT DRIFTS SE. GIVEN THE
LARGE SIZE AND RELATIVE SLOW MOTION OF THIS STRONG SURFACE
LOW...A SIGNIFICANT SWELL EVENT...PERHAPS REACHING 20 FT...
SHOULD UNFOLD ESPECIALLY W OF 60W WHERE THE FLOW WILL MAINTAIN A
N COMPONENT.

ATLANTIC EAST OF 45W...
A NEGATIVELY-TILTED SHORTWAVE TROUGH IS LOCATED FARTHER E
BETWEEN 25W-40W N OF 20N WITH ATTENDANT 1009 MB SURFACE LOW
CENTERED NEAR 33N42W AND A SURFACE TROUGH TRAILING SW ALONG
28N37W TO 23N37W. UPPER DIFFLUENCE E OF THE TROUGH IS PRODUCING
WIDESPREAD CLOUDINESS AND SCATTERED SHOWERS/ISOLATED
THUNDERSTORMS WELL E OF THE SURFACE TROUGH N OF 28N BETWEEN
30W-37W. UNDER THE INFLUENCE OF THE LARGER SCALE AND STRONGER W
ATLC SYSTEM...THE LOW AND ASSOCIATED CONVECTION WILL MOVE
QUICKLY N AND OUT OF THE AREA DURING THE NEXT 12 HOURS.
ELSEWHERE...A PLUME OF AFRICAN DUST AND VERY DRY LOW LEVEL AIR
IS OFF THE COAST AND REACHES AS FAR W AS 30W...INHIBITING CLOUD
DEVELOPMENT S AND E OF THE CAPE VERDE ISLANDS.

$$
WALLACE


WWWW
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