[Tropical] Tropical Weather Discussion

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AXNT20 KNHC 021748
TWDAT

TROPICAL WEATHER DISCUSSION
NWS TPC/NATIONAL HURRICANE CENTER MIAMI FL
105 PM EST WED 02 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 1200 UTC SURFACE ANALYSIS AND SATELLITE IMAGERY THROUGH
1715 UTC.

...ITCZ...

ITCZ AXIS IS CENTERED ALONG 6N10W 1N25W 2N50W.  SCATTERED
MODERATE/ISOLATED STRONG CONVECTION S OF 4N BETWEEN 21W-47W.

...DISCUSSION...

GULF OF MEXICO...
A WEAKENING 1016 MB LOW OVER SE LOUISIANA AND ASSOCIATED FRONTAL
SYSTEM CONTINUE TO BE THE MAIN WEATHER MAKER WITH AREAS OF HEAVY
RAINFALL AFFECTING THE N GULF COAST AND SE UNITED STATES FROM
THE FLORIDA PANHANDLE TO THE SE TIP OF LOUISIANA. THE FRONTAL
SYSTEM CONSISTS OF A WARM FRONT EXTENDING ESE FROM THE LOW TO
28N85W OR ROUGHLY 125 NM WNW OF TAMPA BAY FLORIDA. THE BULK OF
THE HEAVY RAIN AND THUNDERSTORM ACTIVITY IS FOCUSED JUST N OF
THE WARM FRONT. A WEAK TO MODERATE COLD FRONT TRAILS SWD FROM
THE LOW TO THE BAY OF CAMPECHE THEN INLAND OVER MEXICO ALONG THE
E SLOPES OF THE SIERRA MADRE ORIENTAL MOUNTAINS S OF 25N.
OVERCAST CLOUDINESS AND ISOLATED SHOWERS EXISTS BEHIND THE FRONT
IN THE RELATIVELY UNSTABLE ENVIRONMENT CREATED BY COLD ADVECTION
OVER A WARM SEA SURFACE. OVERCAST CLOUDINESS AND SHOWERS EXTEND
INLAND OVER MEXICO AS POST-FRONTAL NLY FLOW ENCOUNTERS THE
WINDWARD FACING SLOPES.  THE PATTERN ALOFT CONTINUES TO SLOWLY
SHARPEN AS A MID/UPPER TROUGH OVER THE SW UNITED STATES AND NW
MEXICO AMPLIFIES SWD AND MIDDLE TO UPPER LEVEL RIDGING OVER THE
GULF NOSES NWD.  THIS EVOLUTION SHOULD PRODUCE WEAKENING UPPER
LEVEL DYNAMICS/LIFT TONIGHT WHILE THE LOW AND ATTENDANT WARM
FRONT MOVE N OF THE AREA LATER THIS EVENING.  HOWEVER...LOW
LEVEL MOISTURE POOLING WILL CONTINUE TO GENERATE A NARROW BAND
OF WIDELY SCATTERED TO LOCALLY SCATTERED SHOWERS ALONG THE COLD
FRONT AS IT MOVES ACROSS FLORIDA TONIGHT CLEARING THE S TIP BY
EARLY FRI.

CARIBBEAN...
MIDDLE TO UPPER RIDGE REMAINS OVER THE W HALF OF THE CARIBBEAN
ANCHORED BY A WELL-DEFINED ANTICYCLONE OVER CENTRAL AMERICA NEAR
HONDURAS.  OVER THE E CARIBBEAN...WEAK TROUGHING HAS DEVELOPED
AS A DEEP LAYERED TROUGH OVER THE W ATLC AMPLIFIES.  THE
RESULTING UPPER FLOW OVER THE CARIBBEAN IS PRIMARILY 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 NLY FLOW BEHIND AN ATLC FRONT FILTERS SWD
OVER THE AREA. A THIN LINE OF BROKEN LOW CLOUDS AND ISOLATED
SHOWERS ARE WITHIN 30 NM EITHER SIDE OF THE LEADING EDGE OF THIS
DRIER AIR FROM ANTIGUA TO 17N74W. A FEW SHOWERS ARE ALSO NOTED
ALONG A WEAK LOW LEVEL TROUGH ALONG THE COAST OF S AMERICA E OF
70W. ADDITIONALLY...THE USUAL AREA OF OVERCAST LOW CLOUDS WITH
ISOLATED SHOWERS IS NOTED INLAND OVER PORTIONS OF NICARAGUA AND
SE HONDURAS AS NLY FLOW ENCOUNTERS WINDWARD FACING SLOPES OF THE
SIERRA MADRE MOUNTAINS.

ATLANTIC WEST OF 45W...
A NEARLY STATIONARY DEEP-LAYERED LOW IS LOCATED ROUGHLY 250 NM E
OF BERMUDA WITH A DEEPENING 995 MB STORM FORCE LOW JUST E OF THE
BERMUDA NEAR 33N62W. ASSOCIATED OCCLUDED FRONT TRAILS SE TO A
TRIPLE POINT NEAR 31N50W WITH COLD FRONT TRAILING SWD ALONG
27N47W 20N55W THEN WEAKENING TO THE N LEEWARD ISLANDS. ONLY A
NARROW 30 NM WIDE BAND OF WIDELY SCATTERED SHOWERS ACCOMPANIES
THE COLD FRONT. A WARM FRONT EXTENDS FROM THE TRIPLE POINT SEWD
TO 28N42W WITH OVERCAST CLOUDINESS AND SCATTERED
SHOWERS/THUNDERSTORMS TO THE N BETWEEN 40W-50W.  A BROKEN
STRATOCUMULUS FIELD IS NOTED W OF THE FRONT TO THE BAHAMAS.
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 SHOWERS/THUNDERSTORMS N OF
29N BETWEEN 50W-65W.  WATER VAPOR IMAGERY INDICATES THE MIDDLE
TO 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 SEWD.  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 NLY COMPONENT.

ATLANTIC EAST OF 45W...
A SECOND NEGATIVELY-TILTED SHORTWAVE TROUGH IS LOCATED FARTHER E
BETWEEN 30W-40W N OF 20N WITH ATTENDANT 1008 MB SURFACE LOW NEAR
29N39W.  A WEAKENING COLD FRONT TRAILS SWD ALONG 26N37W TO
21N38W.  UPPER DIFFLUENCE E OF THE TROUGH IS PRODUCING
WIDESPREAD CLOUDINESS AND WIDELY SCATTERED SHOWERS/THUNDERSTORMS
WELL E OF THE COLD FRONT N OF 22N BETWEEN 30W-37W.  UNDER THE
INFLUENCE OF THE LARGER SCALE AND STRONGER W ATLC SYSTEM...THE
LOW AND ASSOCIATED CONVECTION WILL MOVE QUICKLY NWD AND OUT OF
THE AREA DURING THE NEXT 24 HOURS.  SCATTERED SHALLOW TOPPED
SHOWERS WILL REMAIN ALONG A TRAILING LOW LEVEL TROUGH WHICH WILL
EXTEND FROM 31N34W TO 20N40W BY THU AFTERNOON.  ELSEWHERE...A
PLUME OF AFRICAN DUST AND VERY DRY LOW LEVEL AIR HAS MOVED OFF
THE COAST AND REACHED AS FAR W AS 30W...INHIBITING CLOUD
DEVELOPMENT S AND E OF THE CAPE VERDE ISLANDS.

$$
RHOME




WWWW
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