[Tropical] Tropical Weather Discussion

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AXNT20 KNHC 291738
TWDAT

TROPICAL WEATHER DISCUSSION
NWS TPC/NATIONAL HURRICANE CENTER MIAMI FL
205 PM EDT SAT APR 29 2006

TROPICAL WEATHER DISCUSSION FOR NORTH AMERICA...CENTRAL
AMERICA...THE GULF OF MEXICO...THE CARIBBEAN SEA...NORTHEASTERN
SECTIONS OF SOUTH AMERICA...AND THE 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 5N4W 4N10W 3N20W 2N31W EQ51W.
SCATTERED MODERATE/ISOLATED STRONG CONVECTION IS WITHIN 200 NM
OF THE AXIS BETWEEN 4W-11W. SCATTERED MODERATE CONVECTION IS
WITHIN 300 NM OF THE AXIS BETWEEN 15W-50W.

...DISCUSSION...
GULF OF MEXICO...
A UPPER LEVEL RIDGE EXTENDS FROM THE WEST COAST OF COSTA RICA N
THROUGH THE WESTERN CARIBBEAN INTO THE CENTRAL GULF THEN
CONTINUING WELL N OF THE AREA...AXIS RUNS ALONG 11N86W 26N89W
45N88W...THE UPPER LEVEL FLOW DIVES SE ACROSS THE FLORIDA
PENINSULA...CUBA...AND THE YUCATAN PENINSULA. A MOISTURE
PLUME...ORIGINATING FROM ITCZ CONVECTION OVER THE E PACIFIC
BETWEEN 104W-114W IS BEING EJECTED NORTHEASTWARD AHEAD OF A
MID/UPPER LEVEL TROUGH OVER THE EASTERN PACIFIC ALONG THE
PERIPHERY OF THE RIDGE. A 1003 MB SURFACE LOW PRESSURE LOCATED
NEAR TEXAS/OKLAHOMA BORDER WITH AN ASSOCIATED COLD FRONT
EXTENDS SOUTH ALONG THE TEXAS COAST TO NEAR BROWNSVILLE IS
BEGINNING TO PUSH EASTWARD INTO THE AREA...SCATTERED
MODERATE/ISOLATED STRONG CONVECTION IS NOTED ON RADAR FROM
BROWNSVILLE TEXAS ENE TO NEAR TEXAS CITY EXTENDING OUT FROM THE
COAST 45 MILES. SCATTERED MODERATE CONVECTION NOTED ON RADAR
FROM 28N-29N BETWEEN 89N-95N. ELSEWHERE...SOUTH OF 23N E OF 88W
MODERATE SUBSIDENCE AND ASSOCIATED DRY IS INHIBITING ANY
CONVECTION FROM DEVELOPING OVER THE GULF AT THIS TIME. AT THE
SURFACE...HIGH PRESSURE RIDGING CONTINUES TO DOMINATE MOVING
SOUTHWARD THROUGH 28N83W TO 19N88W.

CARIBBEAN SEA...
WESTERN CARIBBEAN SEA...MID/UPPER LEVEL RIDGING EXTENDS FROM THE
ANTICYCLONE NORTH THROUGH 19N86W ACROSS COASTAL RICA NICARAGUA
HONDURAS CONTINUING NORTH THROUGH THE YUCATAN PENINSULA. FURTHER
EAST...A SHORTWAVE TROUGH IS NOTED WITH ITS MEAN AXIS EXTENDING
SOUTH FROM THE PUERTO RICO TO 13N68W. . CONFLUENT FLOW ON THE
BACK SIDE OF THE TROUGH IS USHERING IN MODERATE TO STRONG
SUBSIDENCE AND ASSOCIATED DRY AIR ACROSS ALMOST THE ENTIRE
CARIBBEAN SEA. WIDELY SCATTERED SHOWERS ARE SEEN PRIMARILY OVER
PUERTO RICO. ELSEWHERE...ONLY SCATTERED LOW CLOUDS WITH SOME
ISOLATED SHOWERS ARE MOVING WESTWARD IN LIGHT TRADE WIND FLOW
ACROSS THE SEA.

ATLANTIC OCEAN...
THE WESTERN N ATLC IS UNDER UPPER LEVEL NORTHWESTERLY FLOW WHICH
MARKS THE WESTERN EXTENT OF BROAD CYCLONIC FLOW DUE TO A RATHER
VIGOROUS SHORTWAVE TROUGH WITH ITS MEAN AXIS EXTENDING ROUGHLY
FROM 32N69W TO 14N64W. THE CYCLONIC FLOW EXTENDS EASTWARD TO
57W. UPPER LEVEL DIFFLUENCE INDICATED EAST OF THE TROUGH
CONTINUES TO ENHANCE CONVECTION WELL EAST OF A SURFACE COLD
FRONT THAT EXTENDS FROM A 1004 MB GALE CENTER NEAR 35N67W
THROUGH 30N67W  SW TO NEAR 21N75W. THIS CONVECTION CONSISTS OF
THE SCATTERED MODERATE/ISOLATED STRONG AND IS FOUND GENERALLY
WITHIN AN AREA BOUNDED FROM 20N-30N BETWEEN 57W-62W. WIDELY
SCATTERED SHOWERS AND ISOLATED THUNDERSTORMS ARE SEEN SOUTH OF
21N BETWEEN 60W-66W. ONLY ISOLATED SHOWERS AND THUNDERSTORMS ARE
ALONG AND WITHIN ABOUT 60 NM EAST OF THE COLD FRONT FROM
26N-27N. SCATTERED TO BROKEN LOW CLOUDS WITH ISOLATED SHOWERS
MOVING SOUTH-SOUTHEAST IN CYCLONIC FLOW DUE TO THE GALE CENTER
ARE PRESENT WEST OF THE COLD FRONT NORTH OF 22N.

TO THE EAST OF THE SHORTWAVE TROUGH...S OF 25N ZONAL FLOW
DOMINATES...UPPER LEVEL HIGH IS LOCATED NEAR 40N47W WITH A UPPER
LEVEL LOW JUST TO THE EAST NEAR 35N30W. AT THE SURFACE...HIGH
PRESSURE RIDGING EXTENDS THROUGH 34N548W TO 17N61W. HIGH
PRESSURE COVERS THE AREA NORTH OF 25N EAST OF 56W. COLD FRONT IS
OVER THE W ATLANTIC ALONG 32N73W 29N75W 26N80W. A SMALL AREA OF
SCATTERED MODERATE CONVECTION IS NEAR THE N BAHAMAS FROM 27N-28N
BETWEEN 75W-77W.  A 1029 MB HIGH CENTERED NEAR 38N41W DOMINATES
THE REMAINDER OF THE ATLANTIC.  IN THE UPPER LEVELS...A TROUGH
IS N OF 23N BETWEEN 70W-80W.  UPPER LEVEL DIFFLUENCE E OF THIS
TROUGH IS PRODUCING A PLUME OF UPPER LEVEL MOISTURE N OF 24N
BETWEEN 67W-71W.  A RIDGE IS N OF 20N BETWEEN 50W-70W.  A TROUGH
IS N OF 20N BETWEEN 30W-50W.

IN THE TROPICS...WLY ZONAL FLOW IS FROM 10N-25N BETWEEN
10W-50W... WHILE SELY FLOW IS FROM EQ-10N BETWEEN 10W-50W. OVER
THE FAR EASTERN ATLANTIC...AN UPPER LEVEL ANTICYCLONE IS
ESTIMATED OVER AFRICA NEAR 7N3W WITH A RIDGE EXTENDING WESTWARD
THROUGH 7N17W TO 7N33W. DEBRIS MOISTURE FROM CONVECTION OF SOUTH
AMERICA...AND THE ITCZ BETWEEN 25W AND 49W...IS STREAMING
NORTHEAST ACROSS THE TROPICAL ATLC WATERS SOUTH OF 10N EAST OF
34W.

$$
JP/WB


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