[Tropical] Tropical Weather Discussion

[EMWIN Server]

AXNT20 KNHC 122307
TWDAT

TROPICAL WEATHER DISCUSSION
NWS TPC/NATIONAL HURRICANE CENTER MIAMI FL
805 PM EDT SUN JUN 12 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.

...TROPICAL WAVES...

E ATLC TROPICAL WAVE ALONG 27W S OF 15N MOVING W 10 KT.  THIS
WAVE IS MARKED BY TURNING IN THE LOW CLOUDS ALONG WITH LIMITED
ITCZ TSTMS.

W-CENTRAL ATLC TROPICAL WAVE ALONG 48W S OF 19N MOVING W 15-20
KT.  THIS IS A HIGH-AMPLITUDE WAVE THAT IS EASILY POSITION BY
LOW CLOUD CURVATURE AND A DEVELOPING V-SHAPE ON SATELLITE
PICTURES.  WIDELY SCATTERED TSTMS ARE WITHIN 60 NM OF THE WAVE
AXIS S OF 13N N OF THE ITCZ.  WAVE SHOULD MOVE INTO THE WINDWARD
ISLANDS ON LATE TUE WITH WIDELY SCATTERED SHOWERS AND A FEW
TSTMS.

E CARIBBEAN TROPICAL WAVE ALONG 66W/67W S OF 16N MOVING W 10
KT.  THE WAVE IS VERY DIFFICULT TO FIND WITH LONG-TERM LOOPS
INCONCLUSIVE.  A LARGE UPPER LOW CONTINUES TO MASK THE WAVE'S
POSITIONS WITH STRONG NLY FLOW.  WIDELY SCATTERED TSTMS BETWEEN
60W-70W FROM 15N-19N ARE PROBABLY ASSOCIATED WITH THE WAVE.

W CARIBBEAN TROPICAL WAVE ALONG 85W S OF 18N MOVING W 10 KT.
CLUSTERS OF TSTMS ARE NEAR THE WAVE AXIS IN THE EPAC...
OTHERWISE THE WEATHER ON THE ATLC SIDE IS RATHER QUIET.

...ITCZ...

ITCZ AXIS IS ALONG 12N16W 7N35W 10N60W.  SCATTERED MODERATE
CONVECTION IS FROM 5.5N-8N BETWEEN 33W-45W.  WIDELY SCATTERED
MODERATE FROM 4N-10N BETWEEN 45W-55W AND WITHIN 45 NM OF LINE
8N13W 7N19W.

...DISCUSSION...

GULF OF MEXICO...
MOST OF THE AREA IS RATHER DRY FOR JUNE WITH DAYTIME TSTMS
SEVERELY INHIBITED BY MODERATE/STRONG SUBSIDENCE ALOFT.  FLORIDA
CONTINUES TO BE AN EXCEPTION TO THE DRY WEATHER WITH LINGERING
MOISTURE FROM ARLENE COMBINING WITH THE W COAST SEA-BREEZE TO
FORM LARGE TSTMS WITH LOCALLY HEAVY RAIN.  HOWEVER MOST OF THE
SUNSHINE STATE WILL GET INTO SOME DRIER WEATHER TOMORROW WITH A
DRY SLOT COMING IN FROM THE E COURTESY OF A LARGE MID/UPPER LOW
OVER THE W ATLC.  BETTER CHANCES OF RAIN WILL SHIFT INTO THE
OPEN WATERS OF THE GULF WITH GENERAL ELY FLOW FAVORING A FEW W
COAST SEABREEZE TSTMS.  LIGHT WINDS AND MOSTLY DRY CONDITIONS
ARE THE RULE FOR THE NEXT FEWS DAY WITH NO SIGN OF THE
SUBTROPICAL RIDGE BUILDING IN AND ANY MID-LATITUDE FEATURES WELL
TO THE N OF THE AREA.

CARIBBEAN SEA...
MUCH WETTER-THAN-AVERAGE WEATHER PATTERN IS LOCKED INTO PLACE
OVER THE CENTRAL AND E CARIBBEAN. AN ANTICYCLONE OVER THE FAR NW
CARIBBEAN CONTROLS THE WEATHER MOSTLY W OF JAMAICA WITH DRIER
AIR ALOFT KEEPING THE OFFSHORE WATERS MOSTLY CONVECTION-FREE
THOUGH LAND AREAS HAVE WIDELY SCATTERED ACTIVITY.  A POWERFUL
MID/UPPER LOW POSITIONED ABOUT 340 NM N OF PUERTO RICO CONTINUES
TO CREATE A LARGE AREA OF DIFFLUENCE N OF 15N ALONG THE GREATER
AND LESSER ANTILLES.  SIMILAR TO YESTERDAY...THE DIFFLUENT
PATTERN ALOFT COUPLED WITH AMPLE DEEP-LAYERED TROPICAL MOISTURE
IS SUPPORTING WIDESPREAD CLOUDINESS AND WIDELY SCATTERED
MODERATE TO STRONG CONVECTION N OF 15N E OF JAMAICA.  LITTLE
CHANGE IS LIKELY TOMORROW WITH THE MID/UPPER LOW NOT MOVING MUCH
AND UPPER FORCING FOCUSES OVER THE NORTHERN CARIBBEAN.  HEAVY
RAIN AND ISOLATED FLOODING IS POSSIBLE OVER THE NE CARIBBEAN FOR
THE NEXT COUPLE OF DAYS.  THIS OVERALL WET PATTERN IS LIKELY TO
CONTINUE ACROSS MUCH OF THE CENTRAL TO E CARIBBEAN THROUGH THE
FIRST PART OF THE WEEK DUE TO THE LOW'S SLOW MOVEMENT.  MODEL
SUGGEST THAT UPPER RIDGING SHOULD BUILD INTO THE SE CARIBBEAN ON
WED...BRINGING A REDUCED CHANCE OF RAIN FOR THE LEEWARD ISLANDS
THOUGH THERE WILL STILL BE SHOWERS IN THE WINDWARD ISLANDS
ASSOCIATED WITH A TROPICAL WAVE.  VERY LIGHT SURFACE WINDS ARE
FORECAST FOR THE W CARIBBEAN FOR THE NEXT SEVERAL DAYS WITH THE
SUBTROPICAL RIDGE SUPPRESSED FAR TO THE NE.

ATLANTIC OCEAN...
LARGE MID/UPPER LOW NEAR 25N66W WITH TROUGH TO THE NW BAHAMAS
DOMINATES THE WEATHER PICTURE IN THE W ATLC.  FEATURE SHOULD
SLOWLY RETROGRADE BENEATH A BUILDING RIDGE OVER THE SE UNITED
STATES WITH VERY DRY AIR ALOFT OVERSPREADING THE BAHAMAS...
FLORIDA AND CUBA DURING THE NEXT 24 HOURS.  THIS LOW MAY
ACTUALLY EXTEND INTO THE LOW-LEVELS WITH A SURFACE TROUGH NOTED
FROM 19N63W TO 25N60W IN THE SURFACE OBSERVATIONS.  A STRONGLY
DIFFLUENT PATTERN COUPLED WITH AMPLE DEEP-LAYERED MOISTURE
CONTINUES TO GENERATE WIDESPREAD CLOUDINESS AND WIDELY SCATTERED
SHOWERS/TSTMS S OF 25N. THIS ACTIVITY WILL SPREAD WESTWARD WITH
THE UPPER LOW OVER THE NEXT TWO DAYS.  A WEAKNESS IN THE
SUBTROPICAL RIDGE IS FORECAST TO REMAIN IN THE W ATLC FOR THE
NEXT SEVERAL DAYS WITH COMPUTER MODELS SUGGESTING THAT SOME SORT
OF LOW COULD FORM ON THE BOUNDARY N OF PUERTO RICO.  THE MODEL
CONSENSUS HAS CHANGED A BIT SINCE YESTERDAY WITH MOST MODELS
SHOWING A WEAK SURFACE LOW FORMING IN THAT VICINITY.  AS THE
UPPER LOW MOVES W...IT SHOULD ALLOWS THE AREA OF DISTURBED
WEATHER NEAR THE NE CARIBBEAN TO MORE UNDER AN AMPLIFIED W ATLC
RIDGE THOUGH THERE IS ONLY A SMALL AREA OF LOW SHEAR.  FARTHER
E...BROAD UPPER TROUGH COVERS THE REMAINDER OF THE SUBTROPICAL
ATLC E OF 55W WITH TROUGH AXIS ALONG 26W.  WEAKENED SUBTROPICAL
RIDGE IS UNDER THIS TROUGH WITH A SURFACE RIDGE AXIS ALONG ABOUT
30N WITH TROPICAL ATLC HAVING MOSTLY 15 KT TRADEWINDS.  IN THE
DEEP TROPICS... MID/UPPER RIDGING EXTENDS FROM JUST S OF
BARBADOS THRU 12N50W SE TO 9N36W THEN ENE TO 11N15W IN W
AFRICA.  THE RIDGE CONTINUES TO GROW IN THE W ATLC WHILE IT IS
SUPPRESSED A BIT S OF AVERAGE IN THE E ATLC.  MODERATE
SUBSIDENCE IS PRESENT BETWEEN 10-20N E OF 40W. AN AREA OF
AFRICAN DUST CAN BE STILL SEEN IN VISIBLE SATELLITE IMAGERY E OF
45W FROM THE ITCZ NWD TO ROUGHLY 21N.

$$
BLAKE


This weather bulletin was brought to you by:
www.nashvilleweather.net