[Tropical] Tropical Weather Discussion

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AXNT20 KNHC 150538
TWDAT

TROPICAL WEATHER DISCUSSION
NWS TPC/NATIONAL HURRICANE CENTER MIAMI FL
105 AM EST TUE 15 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
0515 UTC.

...ITCZ...

ITCZ AXIS IS CENTERED ALONG 5N9W S OF THE EQUATOR NEAR 15W TO
INLAND OVER SOUTH AMERICA NEAR 42W. SCATTERED CLUSTERS OF
SCATTERED MODERATE/ISOLATED STRONG CONVECTION ARE FROM 5N TO S
OF THE EQUATOR BETWEEN 8W-12W AND FROM 35W-51W.

...DISCUSSION...

GULF OF MEXICO...
WEAKENING COLD FRONT CONTINUES TO MOVE E ACROSS THE SE UNITED
STATES N OF THE GULF OF MEXICO. THERE REMAINS LITTLE TEMPERATURE
GRADIENT ACROSS THE BOUNDARY ALTHOUGH MOIST SW FLOW JUST AHEAD
OF THE FRONT IS PRODUCING PATCHES OF SEA FOG UP TO 75 NM OFF THE
LOUISIANA AND E TEXAS COAST. FURTHER E...A SHARP UPPER LEVEL
SHORTWAVE TROUGH OVER THE FAR E UNITED STATES IS PRODUCING A
LINE OF STRONG SHOWERS/THUNDERSTORMS OFF THE COAST FROM NE
GEORGIA TO BEYOND NORTH CAROLINA. THE UPPER TROUGH IS FORECAST
TO LIFT QUICKLY NE WITH ASSOCIATED LINE OF SHOWERS/THUNDERSTORMS
GRADUALLY WEAKENING INTO SCATTERED SHOWERS MOVES ACROSS THE W
ATLC. MID/UPPER LEVEL RIDGING WILL THEN BUILD IN BEHIND THE
EXITING SHORTWAVE CONTINUING TO PRODUCE MAINLY DRY/TRANQUIL
CONDITIONS OVER THE ENTIRE AREA THROUGH MID-WEEK. THE NEXT COLD
FRONT TO AFFECT THE AREA WILL MOVE OFF THE TEXAS COAST LATE WED
NIGHT BUT WILL BE MOISTURE STARVED WITH LITTLE SIGNIFICANT
WEATHER IN ADVANCE. EXPECT A RETURN TO A TYPICAL WINTER REGIME
OF POST-FRONTAL N FLOW AND COLD AIR ADVECTION BY LATE WEEK AS
THE FRONT SWEEPS THROUGH THE GULF.

CARIBBEAN...
THE CARIBBEAN CONTINUES TO BE DOMINATED BY A MID/UPPER LEVEL
RIDGE EXTENDING ALONG THE N COAST OF VENEZUELA NE ACROSS E CUBA/
HISPANIOLA INTO THE W ATLC. RESULTING STRONG SUBSIDENCE AND VERY
DRY/STABLE CONDITIONS ALOFT EXIST ACROSS THE ENTIRE AREA. AS
SUCH...CLOUDINESS AND SHOWER ACTIVITY IS PRIMARILY FOCUSED ALONG
LOW LEVEL MOISTURE BOUNDARIES. THE MOST PROMINENT OF THESE
BOUNDARIES TRAILS ACROSS THE CENTRAL CARIBBEAN FROM S OF PUERTO
RICO NEAR 15N65W TO OFF THE COAST OF COLOMBIA NEAR 13N73W.
OVERCAST LOW CLOUDS WITH SCATTERED SHOWERS ARE N OF THE BOUNDARY
TO THE GREATER ANTILLES. A SECOND AREA OF SCATTERED SHOWERS IS
LOCATED W OF JAMAICA FROM 14N-20N BETWEEN 80W-85W. THIS AREA OF
SHOWER ACTIVITY IS MOVING QUICKLY W WITHIN THE MODERATE/STRONG E
FLOW WHICH HAS BECOME ESTABLISHED ACROSS MUCH OF THE CARIBBEAN
AS HIGH PRESSURE BUILDS S FROM THE W ATLC. WEAK SURFACE TROUGH
EXTENDS FROM THE LESSER ANTILLES NEAR GUADELOUPE S TO THE COAST
OF VENEZUELA NEAR 11N63W WITH ONLY BROKEN LOW CLOUDS AND
ISOLATED SHOWERS WITHIN 75 NM OF THE TROUGH.

ATLANTIC...
THE W ATLC IS UNDER THE INFLUENCE OF DEEP-LAYERED RIDGING WITH
RATHER DRY CONDITIONS NOTED THROUGHOUT THE ENTIRE DEPTH OF THE
ATMOSPHERE EXCEPT NOTED OFF THE IMMEDIATE COAST. DISSIPATING
COLD FRONT IS SLIDING DOWN THE E FLANK OF THE RIDGE E OF BERMUDA
ALONG 32N47W AND TRAILING SW ALONG 27N66W THEN NW BEYOND 32N71W.
HOWEVER...THIS FEATURE IS MOISTURE STARVED AND LACKING UPPER
LEVEL DYNAMICS. THE WEATHER BECOMES MORE ACTIVE OVER THE CENTRAL
ATLC COURTESY OF A COLD/STATIONARY FRONTAL BOUNDARY ALONG 31N43W
28N46W 26N53W WHERE IT DISSIPATES TO 20N59W AND A SURFACE TROUGH
CONTINUES TO THE LESSER ANTILLES NEAR GUADELOUPE. WHILE THE LOW
LEVEL THERMAL GRADIENT IS WEAKENING WITH THIS FEATURE...
SUFFICIENT MOISTURE POOLING AND DYNAMICS ASSOCIATED WITH THE
DEEP LAYERED LOW N OF THE REGION AND A WEAK SHORTWAVE TROUGH
ALONG 46W IS PRODUCING SCATTERED SHOWERS FROM 20N-28N BETWEEN
42W-49W. THE FRONTAL BOUNDARY SHOULD CONTINUE TO WASH OUT OVER
THE CENTRAL ATLC WATERS DURING THE NEXT FEW DAYS BUT SCATTERED
SHOWERS WILL REMAIN. OVER THE FAR E ATLC...A LARGE DEEP-LAYERED
LOW IS CENTERED NW OF THE CANARY ISLANDS NEAR 30N21W WITH A
MID/UPPER LEVEL TROUGH TRAILING S TO N OF THE CAPE VERDE ISLANDS
NEAR 20N28W. CONFLUENT FLOW INTO THE BASE OF THE TROUGH IS
PRODUCING STRONG SUBSIDENCE AND DRY AIR FROM 10N-20N E OF 40W TO
THE COAST OF AFRICA. AT THE SURFACE...A DEEPENING 1008 MB
SURFACE LOW IS LOCATED NW OF THE CANARY ISLANDS NEAR 30N22W.
THERE IS LITTLE SIGNIFICANT WEATHER WITH THIS FEATURE WITH ONLY
A SMALL AREA OF SCATTERED SHOWERS NEAR THE CENTER OF THE LOW
ITSELF. IN FACT...SATELLITE IMAGERY SHOWS MAINLY DRY/STABLE
CONDITIONS TO THE S OF THE LOW DUE IN PART TO AN AREA OF AFRICAN
DUST WHICH HAS PROPAGATED OFF THE CONTINENT OF AFRICA AND IS NOW
BEING ADVECTED INTO THE E SIDE OF THE SURFACE LOW. THE LEADING
EDGE OF THE HIGHEST CONCENTRATION OF DUST EXTENDS FROM THE
CANARY ISLANDS SW THROUGH THE CAPE VERDE ISLANDS TO 13N45W.

$$
WALLACE


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