[Tropical] Tropical Weather Discussion

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AXNT20 KNHC 031149
TWDAT

TROPICAL WEATHER DISCUSSION
NWS TPC/NATIONAL HURRICANE CENTER MIAMI FL
705 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 0600 UTC SURFACE ANALYSIS AND SATELLITE IMAGERY THROUGH
1115 UTC.

...ITCZ...

ITCZ AXIS IS CENTERED ALONG 8N10W 2N23W 3N43W 2N50W. CLUSTERS OF
SCATTERED MODERATE/ISOLATED STRONG CONVECTION ARE S OF 6N W OF
22W TO INLAND OVER SOUTH AMERICA.

...DISCUSSION...

GULF OF MEXICO...
WEAK 1018 MB LOW OVER S ALABAMA/FLORIDA PANHANDLE AND
ASSOCIATED FRONTAL SYSTEM CONTINUES TO BE THE MAIN WEATHER MAKER
WITH A SWATH OF RAIN AFFECTING THE E UNITED STATES FROM S
GEORGIA AND AS FAR NORTH THE E GREAT LAKES. SCATTERED SHOWERS
ARE AFFECTING THE N GULF COAST N OF 26N FROM THE FLORIDA
PENINSULA TO SE ALABAMA. THE FRONTAL SYSTEM CONSISTS OF A WARM
FRONT EXTENDING FROM THE COAST OF FLORIDA NEAR 29N83W TO THE
1018 MB LOW NEAR 30N87W AND A COLD FRONT EXTENDING S ALONG
21N93W TO THE BAY OF CAMPECHE AND THE COAST OF MEXICO NEAR
18N94W. 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
WHILE THE LOW AND ATTENDANT WARM FRONT CONTINUES TO MOVE N OF
THE AREA LATER TODAY. 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...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 OVER GUADELOUPE. BROKEN
STRATOCUMULUS FIELD HAS FILTERED INTO THE NE CARIBBEAN W OF THE
W ATLC FRONT N OF 15N W OF 70W. 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...
A NEARLY STATIONARY DEEP-LAYERED LOW IS LOCATED ROUGHLY 400 NM
ESE OF BERMUDA WITH A DEEPENING 991 MB STORM FORCE LOW CENTERED
NEAR 31N57W. THE SURFACE SYSTEM TO THE E HAS BEEN ABSORBED BY
THE MASSIVE STORM CENTER. ASSOCIATED OCCLUDED FRONT EXTENDS WELL
TO E NEAR TO A 1009 MB LOW TRIPLE POINT NEAR 34N42W WITH A COLD
FRONT EXTENDING S ALONG 24N47W THEN SW TO THE LEEWARD ISLANDS
NEAR GUADELOUPE. A DEVELOPING WARM FRONT EXTENDS FROM THE 1009
MB LOW SE TO 28N34W. A NARROW 30 NM WIDE BAND OF SCATTERED
SHOWERS ACCOMPANIES A WEAK LOW LEVEL TROUGH TO THE E OF THE
FRONT FROM 21N47W TO 26N42W. BROKEN STRATOCUMULUS FIELD IS NOTED
W OF THE FRONT ACROSS THE BAHAMAS AND THE GREATER ANTILLES E OF
79W. 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 MODERATE/ISOLATED STRONG
WITHIN 90/120 NM OF LINE FROM 23N55W TO 32N48W AND SCATTERED
CELLS OF SCATTERED SHOWERS/ISOLATED THUNDERSTORMS N OF 25N
BETWEEN 54W-62W. WATER VAPOR IMAGERY INDICATES THE MID/UPPER
LEVEL TROUGH CONTINUES TO DEEPEN AS A SHORTWAVE FEATURE SWINGS
NE AND ENCOMPASSING THE NEGATIVELY-TILTED SHORTWAVE TROUGH TO
THE E. THIS SHOULD SUPPORT SOME ADDITIONAL STRENGTHENING OF THE
SURFACE LOW OVER THE NEXT 12 TO 24 HOURS AS IT SLOWLY BEGINS TO
DRIFT 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. 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 OF 23N AND E OF
30W INCLUDING THE CAPE VERDE ISLANDS.

$$
WALLACE



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