[Tropical] Tropical Weather Discussion

[EMWIN Server]

AXNT20 KNHC 132350
TWDAT

TROPICAL WEATHER DISCUSSION
NWS TPC/NATIONAL HURRICANE CENTER MIAMI FL
805 PM EDT MON JUN 13 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-CENTRAL ATLC TROPICAL WAVE ALONG 32W S OF 15N MOVING W 10-15
KT.  THE WAVE LIES IN A NORTHWARD BEND OF THE ITCZ WITH A FEW
TSTMS CONFINED TO THE ITCZ.  LITTLE SIGNIFICANT CONVECTION IS
LIKELY WITH THE WAVE OUTSIDE OF THE ITCZ FOR THE NEXT SEVERAL
DAYS AS THE WAVE TRAVELS THROUGH STABLE CONDITIONS IN THE
CENTRAL ATLC... SOMEWHAT REINFORCED BY A RECENT AFRICAN DUST
OUTBREAK.

W ATLC TROPICAL WAVE ALONG 54W S OF 19N MOVING W 15 KT.  THIS IS
A WELL-DEFINED WAVE ON SATELLITE PICTURES WITH A V-SHAPE NOTED.
THE WAVE'S CONVECTION IS GENERALLY INCREASING AS THE WAVE
ENCOUNTERS WARMER WATER AND DIFFLUENT CONDITIONS ALOFT.
TOMORROW SHOULD BE A RATHER CLOUDY.. SHOWERY DAY FOR THE
WINDWARD ISLANDS ESPECIALLY IN THE AFTERNOON.  ANY EFFECTS IN
THE LEEWARD ISLANDS SHOULD HOLD OFF UNTIL WED AS THE NORTHERN
END OF THE WAVE LAGS A BIT BEHIND THE SOUTHERN PORTION.  EARLIER
TSTMS HAVE RECENTLY DIMINISHED BUT WIDELY SCATTERED SHOWERS ARE
S OF 13N BETWEEN 51W-58W.

CENTRAL CARIBBEAN TROPICAL WAVE ALONG 70W S OF 16N MOVING W
10-15 KT. A LARGE EXPLOSION OF CONVECTION NEAR HAITI IS PROBABLY
ASSOCIATED WITH THE WAVE WITH WIDELY SCATTERED MODERATE
CONVECTION FROM 15.5N-18.5N BETWEEN PUERTO RICO AND 71W.  THE
WAVE'S POSITION REMAINS A BIT OF A MYSTERY BUT LONG-TERM LOOPS
SUGGEST THE WAVE IS MOVING INTO THE GENERAL LOW PRESSURE AREA IN
THE SW CARIBBEAN.

CENTRAL AMERICAN TROPICAL WAVE ALONG 90W/91W S OF 20N MOVING W
10-15 KT.  THE WAVE PROBABLY BOOSTED DAYTIME TSTMS OVER THE
YUCATAN WITH STRONG CONVECTION MOVING FROM THE PENINSULA INTO
THE BAY OF CAMPECHE S OF 22N E OF 93W.

...ITCZ...

ITCZ AXIS IS ALONG 11N15 8N25W 7N45W 10N61W.  WIDELY SCATTERED
MODERATE/STRONG CONVECTION EMERGED OFFSHORE OF AFRICA EARLIER
TODAY AND IS NOW FROM 5.5N-10N E OF 23W.  ISOLATED MODERATE FROM
7N-10N BETWEEN 20W-40W.

...DISCUSSION...

GULF OF MEXICO...
THE NE PART OF FLORIDA IS THE ONLY AREA WITH TYPICAL DIURNAL
TSTMS FORMING ALONG THE SEA-BREEZES.  THE REASON FOR THIS DRY
JUNE PATTERN LIES WITH TWO FACTORS... THE FIRST BEING STRONG
SUBSIDENCE ALOFT SQUELCHING ANY SORT OF CONVECTION IN THE
WESTERN GULF...AND THE SECOND IS DRY AIR ALOFT FROM THE ATLC
BEING ADVECTED AROUND THE WESTERN SIDE OF THE MID-OCEANIC TROUGH
OVER THE W ATLC.  NE FLORIDA WAS CAUGHT IN BETWEEN THESE TWO
SYSTEMS AND STILL HAD SOME LINGERING LOW-LEVEL MOISTURE FROM
ARLENE SO THEY WERE ABLE TO FORM TSTMS.  A FEW TSTMS ARE
POSSIBLE OVER THE S-CENTRAL GULF AND FAR NE FLORIDA TOMORROW..
OTHERWISE MOSTLY DRY WEATHER SHOULD CONTINUE.  ANOTHER HUGE
ROUND OF TSTMS DEVELOPED OVER YUCATAN TODAY AND MOVED OFFSHORE
INTO THE BAY OF CAMPECHE WITH DEEP-LAYERED MOISTURE IN PLACE AND
A WEAK UPPER RIDGE ALOFT.  A REPEAT IS POSSIBLE TOMORROW BEFORE
CHANCES DIMINISH AS THE MID-OCEANIC TROUGH DIGS FARTHER INTO THE
NW CARIBBEAN.  WEAK HIGH PRESSURE DROPS INTO THE NORTHERN GULF
BY MID-WEEK... WITH DRY CONDITIONS FOR MOST OF THE GULF COAST
AND A BIT WETTER PATTERN FOR THE E COAST OF S FLORIDA WITH WLY
WINDS FORECAST.

CARIBBEAN SEA...
DISTURBED WEATHER CONTINUES FOR THE CENTRAL CARIBBEAN WITH THE
MID-OCEANIC TROUGH BUILDING IN FROM CENTRAL CUBA TO ABOUT SWAN
ISLAND.  DIFFLUENT PATTERN ALOFT IN COMBINATION WITH
DEEP-LAYERED MOISTURE AND THE OCCASIONAL TROPICAL WAVE IS
LEADING TO SCATTERED TSTMS N OF 14N BETWEEN 71W-77W.  SURFACE
PRESSURES ARE MUCH BELOW-AVERAGE WITH A NOAA BUOY REPORTING
PRESSURE BELOW 1006 MB THIS EVENING.  A SURFACE TROUGH IS
ALIGNED FROM ROUGHLY SW HAITI TO SAN ANDRES ISLANDS WITH BUOY
AND SURFACE OBSERVATION SUGGESTING A LOW HAS FORMED JUST E OF
SAN ANDRES.  THERE MAY ALSO BE A LOW CLOSER TO THE TSTMS NEAR
15N77W BUT THERE IS A FAIR AMOUNT OF WLY SHEAR IMPEDING
DEVELOPMENT.  COMPUTER MODELS SUGGEST THAT REGARDLESS OF
DEVELOPMENT...THE TROUGH/LOW WILL LIFT NORTHWARD WITH TIME AND
HAVE STRONG UPPER SUPPORT... LEADING TO VERY HEAVY RAIN...
POSSIBLE FLOODING AND MUDSLIDES OVER HISPANIOLA INTO JAMAICA
TOMORROW.  THIS OVERALL WET PATTERN IS LIKELY TO CONTINUE ACROSS
MUCH OF THE N-CENTRAL CARIBBEAN THROUGH WED DUE TO THE NW
CARIBBEAN UPPER TROUGH'S SLOW MOVEMENT.  UPPER RIDGING IS
BUILDING INTO THE SE CARIBBEAN TONIGHT... A HARBINGER OF DRIER
WEATHER THOUGH DEEP-LAYERED MOISTURE SHOULD KEEP THE E CARIBBEAN
WITH A SLIGHTLY HIGHER-THAN-AVERAGE RAIN CHANCE.  LIGHT SURFACE
WINDS ARE FORECAST FOR THE W AND CENTRAL CARIBBEAN FOR THE NEXT
SEVERAL DAYS WITH THE SUBTROPICAL RIDGE SUPPRESSED FAR TO THE
NE.

ATLANTIC OCEAN...
BASICALLY THE PATTERN HAS TURNED RATHER HIGH AMPLITUDE WITH A
TROUGH/RIDGE/TROUGH ORIENTATION.  MID-OCEANIC TROUGH EXTENDS
FROM 31N60W IN THE W ATLC SW TO CENTRAL CUBA WITH VERY DRY AIR
ALOFT W OF THE TROUGH AXIS AND PLENTIFUL MULTI-LAYERED CLOUDS E
OF THE TROUGH AXIS.  SURFACE TROUGH EXTENDS FROM NEAR 20N66W N
OF PUERTO RICO TO 28N62W WITH A POSSIBLE LOW FORMING NEAR
23N63W.  ISOLATED TSTMS ARE AHEAD OF THE TROUGH FROM 19N-23N W
OF 56W.  COMPUTER MODELS STILL SUGGEST THAT SOME SORT OF LOW
COULD FORM ON THE BOUNDARY AND TRACK NE... THOUGH VERTICAL WIND
SHEAR IS RATHER HIGH FOR SIGNIFICANT DEVELOPMENT.   THE CENTRAL
ATLC IS DOMINATED BY AN EXPANDING MID/UPPER HIGH NEAR 14N50W
WITH RIDGING NORTHWARD ALONG 50W AND EASTWARD TO 10N40W THEN
10N25W ACROSS THE TROPICAL ATLC.  THIS RIDGE IS MUCH FARTHER N
THAN AVERAGE WITH ELY S OF 10N W OF 30W THROUGHOUT THE DEEP
TROPICS.  IN THE NE ATLC... BROAD UPPER TROUGH LIES FROM 32N24W
TO 15N35W PRODUCING LITTLE SIGNIFICANT WEATHER WITH SOME
MODERATE SUBSIDENCE E OF 30W BETWEEN 10N-20N.  WEAKENED
SUBTROPICAL RIDGE IS UNDER THIS TROUGH WITH A 1019 MB HIGH NEAR
27N WITH E-W RIDGING FROM 26N-28N E OF 50W.  AN AREA OF AFRICAN
DUST CAN BE STILL SEEN IN VISIBLE SATELLITE IMAGERY E OF 50W
FROM THE ITCZ NWD TO ROUGHLY 21N.

$$
BLAKE

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