[Tropical] Tropical Weather Discussion

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AXNT20 KNHC 302329
TWDAT

TROPICAL WEATHER DISCUSSION
NWS TPC/NATIONAL HURRICANE CENTER MIAMI FL
805 PM EDT THU JUN 30 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
2315 UTC.

...TROPICAL WAVES...

EAST ATLANTIC TROPICAL WAVE IS BETWEEN SENEGAL AND THE CAPE
VERDES ALONG 20W S OF 16N MOVING W 10-15 KT. THERE WAS A LITTLE
CONFUSION OVER THE PAST FEW DAYS AS TO WHETHER OR NOT THIS WAVE
HAD MOVED OFF THE AFRICAN COAST...BUT THE DAKAR SOUNDING FINALLY
CONFIRMED A SEND OFF AROUND 18Z YESTERDAY. THE WAVE IS SHALLOW
AND ONLY EXTENDS FROM THE SFC TO ABOUT 800 MB (6500 FT) DUE TO
STRONG EASTERLIES IN THE MID LEVELS. SATELLITE IMAGERY IS OF
LITTLE HELP AT THE MOMENT MAINLY BECAUSE THE WAVE IS BEING
OVERSHADOWED BY THE LARGE WAVE TO ITS W. NO SIGNIFICANT
CONVECTION.

CENTRAL ATLANTIC TROPICAL WAVE ALONG 40W S OF 23N MOVING W 10-15
KT. THE WAVE CURRENTLY HAS A COMPLEX STRUCTURE AS IT APPEARS THE
SFC/LOW-LEVEL CIRCULATION IS DISPLACED ABOUT 300-350 NM TO THE W
OF THE MID-LEVEL VORT MAX. THE ITCZ CONTINUES TO BE INFLECTED
ALONG A SW/NE LINE ACROSS THE WAVE AXIS AND A LARGE AREA OF DRY
STABLE AIR LIES TO THE W ALL THE WAY TO THE LESSER ANTILLES.
THIS WILL INDUCE SPECTACULAR WEATHER OVER THE WINDWARD AND
LEEWARD ISLANDS THRU THE WEEKEND BEFORE SHOWERS/TSTMS BEGIN TO
INCREASE SUN NIGHT WITH THE APPROACH OF THE WAVE. AS FAR AS
TROPICAL CYCLONE DEVELOPMENT...ALL NUMERICAL MODELS HAVE BACKED
OFF CONSIDERABLY IN FORMING A STRONG SFC LOW AND INSTEAD SHOW A
HIGHLY AMPLIFIED WAVE CROSSING THE ISLANDS ON MON.

CENTRAL CARIBBEAN TROPICAL WAVE EXTENDS FROM NW VENEZUELA TO
HISPANIOLA ALONG 70W S OF 21N MOVING W 15-20 KT. THE WAVE IS
RUNNING INTO A HIGHLY DIFFLUENT UPPER LEVEL ENVIRONMENT NEAR AN
UPPER LEVEL HIGH CENTERED S OF JAMAICA WHICH HAS CAUSED
WIDESPREAD TSTM ACTIVITY TO BREAK OUT PRIMARILY OVER THE
CNTRL/WRN CARIBBEAN WATERS. NUMEROUS MODERATE/STRONG CONVECTION
DIRECTLY ASSOCIATED WITH THE WAVE IS FROM 13N-18N BETWEEN
70W-76W (BUT OTHER CONVECTION LIES FARTHER W...SEE DISCUSSION
BELOW). SCATTERED MODERATE/STRONG ALSO LIES ALONG THE N HALF OF
HISPANIOLA WITH WIDELY SCATTERED SHOWERS/TSTMS OFFSHORE FROM
20N-22N BETWEEN 67W-69W. A LARGE BLOW-UP OF NUMEROUS STRONG
CONVECTION IS ALSO JUST NW OF LAKE MARACAIBO OVER THE GUAJIRA
PENINSULA OF COLOMBIA. DEEP TROPICAL MOISTURE ASSOCIATED WITH
THE WAVE WILL CONTINUE MOVING W AND SHOULD AFFECT MANY PARTS OF
THE W CARIBBEAN WITH SCATTERED TSTMS/HEAVY RAINFALL THRU LATE
MON.

...ITCZ...

ITCZ AXIS IS CENTERED ALONG 15N10W 11N21W 12N32W 6N58W 12N76W
9N84W. SCATTERED MODERATE CONVECTION MOVING WWD TOWARDS THE
COAST OF SENEGAL...GUINEA-BISSAU...AND GUINEA FROM 9N-15N
BETWEEN 12W-16W. ISOLATED MODERATE WITHIN 120 NM OF THE AXIS
BETWEEN 16W-40W. WIDELY SCATTERED SHOWERS/TSTMS 150 NM N OF THE
AXIS BETWEEN 40W-49W.

...DISCUSSION...

MEXICO...
THE REMNANT MID-LEVEL CIRCULATION OF T.D. BRET CONTINUES TO MOVE
NW OVER THE MEXICAN PLATEAU AND IS LOCATED BETWEEN TORREON AND
MONTERREY...CAUSING GENERALLY ISOLATED TSTMS FROM 24N-26N
BETWEEN 100W-103W. SCATTERED MODERATE CONVECTION IS ALSO
DEVELOPING ALONG A CONVERGENCE LINE THAT RUNS FROM DURANGO SE TO
PUEBLA...INCLUDING GREATER MEXICO CITY.

GULF OF MEXICO...
THE ATLANTIC SUBTROPICAL RIDGE HAS BUILT IN OVER THE GULF OF
MEXICO WITH THE MAIN AXIS ALONG 26N AND SINCE THERE IS VERY
LITTLE DEEP-LAYERED ATMOSPHERIC MOISTURE AT THE MOMENT...MOST OF
THE AREA IS UNDER DRY AND CLOUDLESS SKIES. A WEAK SFC TROF IS
EMBEDDED ALONG THE NRN PERIPHERY OF THE RIDGE FROM N/CNTRL
FLORIDA NW TO SE LOUISIANA BUT HAS TRIGGERED ONLY ISOLATED
TSTMS. A CUT-OFF MID/UPPER LEVEL LOW IS CENTERED S OF LOUISIANA
NEAR 27N90W AND IS PRODUCING A SUBSIDENT ENVIRONMENT OVER THE NW
GULF. EASTERLY UPPER LEVEL FLOW OVER THE YUCATAN AND BAY OF
CAMPECHE HAS DISALLOWED THE UPPER LOW FROM TAPPING INTO MUCH
TROPICAL MOISTURE...WHICH HAS KEPT THE E GULF MOSTLY DRY AS
WELL. THE MOST WIDESPREAD CONVECTIVE ACTIVITY IS OVER FLORIDA
WHERE SCATTERED MODERATE CONVECTION HAS FORMED FROM MIAMI TO
CAPE CANAVERAL...AND WIDELY SCATTERED MODERATE FROM TALLAHASSEE
TO JACKSONVILLE. SCATTERED MODERATE IS ALSO ALONG THE W COAST OF
THE YUCATAN PENINSULA.

CARIBBEAN...
THE WEATHER ASSOCIATED WITH THE TRPCL WAVE ALONG 70W HAS MELDED
WITH A SECOND AREA OF TSTMS OVER THE W/SW CARIBBEAN TO PRODUCE A
LARGE COMPLEX OF SCATTERED MODERATE/STRONG CONVECTION THAT
EXTENDS FROM COLOMBIA NWD TO HAITI AND JAMAICA BETWEEN 70W-82W.
THE ITCZ HAS LIFTED N OF PANAMA INTO THE SW CARIBBEAN AND HAS
PROVIDED A GOOD FOCUS FOR LOW-LEVEL CONVERGENCE AND THE
DEVELOPMENT OF TSTMS. IN ADDITION...STRONG DIFFLUENCE IN THE
UPPER LEVELS COURTESY OF AN UPPER HIGH NEAR 14N78W HAS ALLOWED
THESE TSTMS TO BLOSSOM QUICKLY AND EXPAND OVER A LARGE AREA. A
WELL-DEFINED MID-LEVEL CIRCULATION EMERGED FROM THE CONVECTION
NEAR 13N79W BUT THERE IS NO EVIDENCE THAT A CORRESPONDING SFC
CIRCULATION HAS ALSO DEVELOPED. HOWEVER...CONVECTION IS EXPECTED
TO PERSIST OVER THE AREA WITH THE POTENTIAL FOR VERY HEAVY
RAINFALL AND POSSIBLE FLOODING OVER PARTS OF CENTRAL AMERICA
THRU MON. THE REST OF THE CARIBBEAN WILL EXPERIENCE RELATIVELY
DRY WEATHER AHEAD OF THE NEXT TRPCL WAVE WHICH IS SCHEDULED TO
BEGIN AFFECTING THE LESSER ANTILLES SUN NIGHT.

ATLANTIC...
AN AMPLIFIED AND STRONGLY TILTED UPPER RIDGE AXIS EXTENDS FROM
CNTRL FLORIDA NEWD PAST 32N66W WITH HIGH CLOUDINESS EXTENDING
OVER MUCH OF THE W ATLC WATERS N OF 26N. A SHARP UPPER TROF IS
LOCATED DOWNSTREAM ALONG 32N56W 23N63W AND IS COLLOCATED WITH A
SFC TROF ALONG 25N67W 32N58W WITH IS PRODUCING WIDELY SCATTERED
MODERATE CONVECTION FROM 27N-31N BETWEEN 53W-58W. IN
ADDITION...A SFC TROF WHICH BROKE OFF FROM THE CNTRL CARIBBEAN
TRPCL WAVE STRETCHES NE OF THE VIRGIN ISLANDS ALONG 19N63W
24N58W AND HAS TRIGGERED SCATTERED MODERATE CONVECTION FROM
20N-24N BETWEEN 56W-63W. THE REMAINDER OF THE ATLC IS DOMINATED
BY A HARMLESS UPPER LOW NEAR 32N27W AND A SHEARED UPPER TROF
EXTENDING FROM THE CANARY ISLANDS SW TO 14N40W. A STRONG
LOW-LEVEL RIDGE IS PICKING THE WINDS UP A BIT OVER THE E
ATLC...ESPECIALLY NEAR THE COAST OF MOROCCO AND WRN SAHARA WHERE
20-30 KT IS BEING REPORTED. THE UPPER RIDGE EXTENDING OUT OF
AFRICA IS ALONG 15N AND STRETCHES WWD TO 37W...WHICH IS HELPING
TO ADVECT SOME UPPER MOISTURE FARTHER N INTO THE ATLC.

$$
BERG


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