[Tropical] Tropical Weather Discussion

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AXNT20 KNHC 071755
TWDAT

TROPICAL WEATHER DISCUSSION
NWS TPC/NATIONAL HURRICANE CENTER MIAMI FL
205 PM EDT SAT JUN 07 2008

TROPICAL WEATHER DISCUSSION FOR NORTH AMERICA...CENTRAL
AMERICA...GULF OF MEXICO...CARIBBEAN SEA...NORTHERN SECTIONS OF
SOUTH AMERICA...AND ATLANTIC OCEAN TO THE AFRICAN COAST FROM THE
EQUATOR TO 32N. THE FOLLOWING INFORMATION IS BASED ON SATELLITE
IMAGERY...METEOROLOGICAL ANALYSIS...WEATHER OBSERVATIONS...AND
RADAR.

BASED ON 1200 UTC SURFACE ANALYSIS AND SATELLITE IMAGERY THROUGH
1715 UTC.

...TROPICAL WAVES...

THE TROPICAL WAVE THAT WAS PREVIOUSLY ALONG 30W S OF 13N IS
ADJUSTED AHEAD NEAR 37W BASED ON SFC OBSERVATIONS...SATELLITE
PICTURES AND LOW-LEVEL DERIVED WINDS. A WEAK CYCLONIC TURNING
IS SEEN ALONG THE WAVE AXIS NEAR 7N. IN ADDITION...THE TPW
ANIMATION FROM CIMSS SHOWS A PEAK OF MOISTURE JUST BEHIND THE
WAVE AXIS. SCATTERED MODERATE CONVECTION IS WITHIN 120 NM E OF
WAVE AND WITHIN 50 NM AHEAD OF THE WAVE AXIS FROM 7N TO 9N.

A TROPICAL HAS ENTERED THE EASTERN CARIBBEAN. IT AXIS EXTENDS
ALONG 61W/62W S OF 20N MOVING W 10-15 KT. THE MIMIC-TPW PRODUCT
INDICATES A GOOD SURGE OF MOISTENED AIR EITHER SIDE OF THE WAVE
AXIS BUT MAINLY SOUTH OF 16N. THE WAVE IS GENERATING SOME SHOWER
ACTIVITY OVER THE WINDWARD ISLANDS. TRINIDAD REPORTED 0.57
INCHES OF RAIN THIS MORNING. ISOLATED MODERATE CONVECTION IS
OVER THE LESSER ANTILLES.

A TROPICAL WAVE IS OVER CENTRAL AMERICA ALONG 84W S OF 17N
MOVING W 10-15 KT. WAVE REMAINS EMBEDDED WITHIN AN AREA OF DEEP
LAYERED MOISTURE MAINLY ACROSS THE SW CARIBBEAN WHERE UPPER
DIFFLUENCE IS HELPING TO INDUCE CLUSTERS OF MODERATE CONVECTION.

...ITCZ...

ITCZ AXIS IS CENTERED ALONG 5N10W 4N25W 6N34W 6N46W 5N55W.
CLUSTERS OF SCATTERED MODERATE/ISOLATED STRONG CONVECTION ARE
FROM 3N TO THE SW COAST AFRICA BETWEEN THE PRIME MERIDIAN AND
7W. SIMILAR CONVECTION IS NEAR 4N13W AND 2N21W. SCATTERED
MODERATE CONVECTION IS FROM 4N-8N BETWEEN 40W-52W.

...DISCUSSION...

GULF OF MEXICO...
AS OF 1500 UTC...A SFC TROUGH IS ANALYZED FROM NEAR TAMPICO
MEXICO TO THE BAY OF CAMPECHE. THIS FEATURE IS PRODUCING
SCATTERED MODERATE CONVECTION MAINLY SOUTH OF 26N WEST OF 94W.
LIGHTNING DATA DEPICTS SCATTERED TSTMS IN THIS AREA...
PARTICULARLY BETWEEN 23N AND 26N. THE REMAINDER OF THE GULF IS
UNDER THE INFLUENCE OF A SURFACE RIDGE ANCHORED ON A 1023 HIGH
LOCATED OVER THE W ATLC 30N76W. PRES GRADIENT BETWEEN THE SFC
HIGH AND THE TROUGH IS PRODUCING MODERATE TO FRESH SE WINDS OVER
THE WESTERN HALF OF THE GULF. A QSCAT PASS FROM AROUND 1200 UTC
SHOWED WIND BARS OF 15 TO 20 KT OVER THE SAME AREA. THESE WINDS
ARE EXPECTED TO PERSIST THE REST OF THE WEEKEND. IN THE UPPER
LEVELS...A MID/UPPER LEVEL RIDGE CENTERED OVER THE SE CONUS
DOMINATES MOST OF THE GULF REGION GIVING THE AREA MODERATE TO
STRONG SUBSIDENCE. THE EXCEPTION IS THE SW GULF WHERE A FAIR
AMOUNT OF UPPER LEVEL MOISTURE IS FOUND. EXPECT LITTLE CHANGE IN
THE SURFACE PATTERN OVER THE NEXT 24 HOURS AS THE SFC HIGH
REMAINS NEARLY STATIONARY.

CARIBBEAN...
WV IMAGERY SHOWS A WELL DEFINED MID/UPPER LEVEL LOW OVER THE W
ATLC JUST N OF THE SE BAHAMAS NEAR 24N72W. A CYCLONIC FLOW
ASSOCIATED WITH THIS SYSTEM COVERS THE WESTERN AND CENTRAL
CARIBBEAN WHILE AN UPPER RIDGE EXTENDS NWD OVER THE FAR EAST
PORTION OF THE BASIN ALONG 61W/62W. AN UPPER TROUGH EXTENDS FROM
THE LOW THROUGH THE WINDWARD PASSAGE TO THE CENTRAL CARIBBEAN. A
SFC TROUGH...REFLECTION OF THESE UPPER LEVEL FEATURES WAS
ANALYZED ON THE 12Z MAP EXTENDING ACROSS THE SE BAHAMAS AND THE
WINDWARD PASSAGE TO JUST N OF JAMAICA. THIS WEATHER PATTERN IS
HELPING TO INDUCE SOME SHOWER/TSTM ACTIVITY OVER EASTERN CUBA
AND COASTAL WATERS. TWO TROPICAL WAVES ARE ALSO AFFECTING THE
REGION. SEE TROPICAL WAVE SECTION FOR DETAILS. A BAND OF
TRANSVERSE HIGH CLOUDS AROUND THE BASE OF THE UPPER-LEVEL LOW
PREVIOUSLY MENTIONED CROSSES THE GULF OF HONDURAS AND CABO
GRACIAS A DIOS NICARAGUA...THEN CONTINUES EWD ACROSS THE CENTRAL
CARIBBEAN. MODERATE TO FRESH TRADEWINDS ARE NOTED OVER THE
CARIBBEAN SEA WITH THE STRONGEST WINDS...AS USUAL JUST OFFSHORE
THE COLOMBIAN COAST WHERE AN EARLIER QSCAT PASS SHOWED ELY WINDS
OF 20 TO 25 KT. HIGH PRES N OF AREA WILL MAINTAIN FRESH E TRADE
WINDS THROUGH WED.

ATLANTIC...
OUTSIDE OF THE FEATURES OUTLINED ABOVE...A 1024 MB HIGH IS
CENTERED OVER THE W ATLANTIC NEAR 30N76W. A LARGE 1028 MB HIGH N
OF THE AZORES DOMINATES THE REMAINDER OF THE ATLC FORECAST AREA
PRODUCING MOSTLY FAIR WEATHER. IN BETWEEN...THERE IS A WEAK SFC
TROUGH EXTENDING FROM 30N61W TO 25N64W. THE MID/UPPER LEVEL LOW
CENTERED NEAR 24N72W WILL CONTINUE TO MOVE WWD TOWARD THE NW
BAHAMAS...AND POSSIBLY CENTRAL FLORIDA. THIS LOW IS GENERATING
SCATTERED SHOWERS AND TSTMS. A TROUGH IS OVER THE CENTRAL
ATLANTIC WHILE A NEARLY ZONAL FLOW DOMINATES THE EASTERN ATLC.
THE UPPER TROUGH SUPPORTS A COLD FRONT THAT LIES N OF AREA BUT
THIS FRONT IS EXPECTED TO DIP INTO THE FORECAST REGION ACROSS
THE CENTRAL ATLC IN 24 HOURS. A SHORT-WAVE TROUGH ALONG 38W N OF
24N IS GENERATING AN AREA OF CLOUDINESS WITH POSSIBLE SHOWERS
FROM 25N-31N BETWEEN 32W AND 38W. PATCHES OF LOW LEVEL CLOUDS
ARE SEEN N OF THE ITCZ AND EAST OF 40W. IN THE TROPICS...AN
UPPER LEVEL HIGH IS CENTERED OVER THE CAPE VERDE ISLANDS WITH
THE ANTICYCLONIC FLOW REACHING 40W.

$$
GR







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