[Tropical] Tropical Weather Discussion

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AXNT20 KNHC 142326
TWDAT

TROPICAL WEATHER DISCUSSION
NWS TPC/NATIONAL HURRICANE CENTER MIAMI FL
705 PM EST MON 14 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 1800 UTC SURFACE ANALYSIS AND SATELLITE IMAGERY THROUGH
2245 UTC.

...ITCZ...

ITCZ AXIS IS CENTERED ALONG 4N8W 3N22W 2N29W 2N42W EQ50W.
ISOLATED MODERATE FROM 1N-5N BETWEEN 8W-12W.  SIMILAR CONVECTION
IS WITHIN 90 NM OF 2N38W AND 2.5N48W.

...DISCUSSION...

GULF OF MEXICO...
WEAK COLD FRONT MOVING THRU S LOUISIANA IS DISSIPATING WITH
LITTLE INFLUENCE IN THE AREA.  MOST OF THE SEA FOG HAS BEEN
DIMINISHING OFFSHORE OF THE TX/LA COAST WITH GENERALLY LIGHT
WINDS IN THE WHOLE NW GULF.  HOWEVER THIS SEA FOG WILL PROBABLY
REDEVELOP OVERNIGHT IN THE COLD SHELF WATERS AND IN COASTAL
LOCATIONS ALONG THE NW GULF.  FURTHER E...AN EXITING UPPER LEVEL
SHORTWAVE TROUGH ALONG ABOUT 80W EARLIER PRODUCED SOME TSTMS
WHICH HAVE NOW DISSIPATED AS THE UPPER SUPPORT LEAVES THE USA
OVER MORE STABLE COASTAL WATERS.  ZONAL UPPER FLOW IS OVER THE
GULF NOW... FOLLOWED BY MIDDLE TO UPPER LEVEL RIDGING BUILDING
IN BEHIND THE EXITING SHORTWAVE PRODUCING 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 HAVE LITTLE SIGNIFICANT WEATHER IN ADVANCE.
EXPECT A QUICK POST-FRONTAL NLY FLOW AND COLD AIR ADVECTION BY
LATE WEEK AS THE FRONT SWEEPS THROUGH THE GULF... THOUGH THIS
COLD FRONT WILL BE WEAKER THAN THE SURGE LAST WEEK.

CARIBBEAN...
LITTLE CHANGE HERE AS THE CARIBBEAN CONTINUES TO BE DOMINATED BY
MID/UPPER LEVEL RIDGING EXTENDING FROM THE N COAST OF VENEZUELA
NWD ACROSS 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 SWD FROM A DISSIPATING ATLC
STATIONARY FRONT OVER THE N LEEWARD ISLANDS TO THE CENTRAL
CARIBBEAN NEAR 12N73W.  THE BOUNDARY IS ACCOMPANIED BY 120 NM
WIDE LINE OF WIDELY SCATTERED SHOWERS.  A SECOND AREA OF SHOWERS
IS LOCATED S OF GRAND CAYMAN FROM 15N-19N BETWEEN 81W-84W.  BOTH
AREAS OF SHOWER ACTIVITY ARE MOVING QUICKLY WESTWARD WITHIN THE
MODERATE ELY FLOW WHICH HAS BECOME ESTABLISHED ACROSS MUCH OF
THE CARIBBEAN AS HIGH PRES BUILDS SWD OVER THE W ATLC.  ENHANCED
RAINS ARE LIKELY OVER PUERTO RICO TONIGHT IN ADDITION TO THE
REST OF THE NE LEEWARD ISLANDS FOR THE NEXT DAY OR TWO.

ATLANTIC...
THE W ATLC IS UNDER THE INFLUENCE OF DEEP-LAYERED RIDGING WITH
RATHER DRY CONDITIONS DESPITE A WEAK SHORTWAVE EXITING FLORIDA.
A COLD FRONT IS SLIDING DOWN THE E FLANK OF THE RIDGE ENTERING
THE AREA ALONG 32N51W SW ALONG 28N60W THEN DISSIPATING NW BEYOND
31N71W. HOWEVER...THIS FEATURE IS MOISTURE-STARVED AND LACKING
UPPER DYNAMICS WITH ONLY A NARROW BAND OF ISOLATED SHOWERS ALONG
THE LEADING EDGE. THE WEATHER BECOMES A LITTLE MORE ACTIVE OVER
THE CENTRAL ATLC COURTESY OF A COLD FRONT FROM 31N42W TO 27N51W
THEN STATIONARY AND DISSIPATING TO THE N LEEWARD ISLANDS NEAR
BARBUDA.  MID/UPPER SHORTWAVE ALONG ABOUT 50W N OF 20N IS
SUPPORTING WIDELY SCATTERED SHOWERS AND A FEW TSTMS FROM 21N-26N
BETWEEN 50W-58W.  THE FRONTAL BOUNDARY SHOULD WASH OUT OVER THE
CENTRAL ATLC WATERS DURING THE NEXT FEW DAYS BUT WIDELY
SCATTERED SHOWERS WILL PERSIST.  OVER THE FAR NE ATLC...A LARGE
DEEP-LAYERED LOW IS SPINNING NW OF THE CANARY ISLANDS NEAR
30N21W.  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 1010 MB SFC LOW IS
LOCATED ABOUT 200 NM NW OF THE CANARY ISLANDS WITH WIDELY
SCATTERED SHOWERS N OF 28N BETWEEN 19W-26W.  FARTHER
S...SATELLITE IMAGERY SHOWS MAINLY DRY/STABLE CONDITIONS TO THE
SOUTH OF THE LOW DUE IN PART TO AN AREA OF DUST WHICH HAS
PROPAGATED OFF THE CONTINENT OF AFRICA AND IS NOW MOVING WEST
WITHIN THE LOW LEVEL ELY FLOW.  THE LEADING EDGE OF THE HIGHEST
CONCENTRATION OF DUST EXTENDS FROM THE CANARY ISLANDS SW TO THE
CAPE VERDES THEN WESTWARD TO NEAR 13N55W WITH VISIBILITIES
DROPPING BELOW 5 MILES AT TIMES.  ZONAL FLOW ALOFT DOMINATES THE
TROPICAL ATLC WITH ONLY BROAD TROUGHING FROM THE E ATLC LOW.
BLOCKING CONDITIONS IN THE FAR NE ATLC SHOULD KEEP THE CANARY
ISLANDS LOW MOVING SLOWLY THRU THE MEDIUM RANGE.

$$
BLAKE

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