000
FXCA20 KWBC 191114
PMDCA

TROPICAL DISCUSSION - INTERNATIONAL DESKS
NWS WEATHER PREDICTION CENTER COLLEGE PARK MD
714 AM EDT WED JUN 19 2013

PRELIMINARY DISCUSSION FOR PUERTO RICO AND THE USVI. TUTT LOW
NORTH OF THE ISLANDS EXTENDS A TROUGH TO THE EASTERN CARIBBEAN.
THIS AXIS HAS STARTED ITS WESTWARD MIGRATION AS A CELL OF THE
SUBEQUATORIAL RIDGE BUILDS FROM THE EAST. AS A RESULT...FORECAST
AREA TRANSITIONING FROM MID/UPPER CONVERGENCE TO DIVERGENCE...WITH
ENVIRONMENTAL CONDITIONS BECOMING FAVORABLE FOR DEEP CONVECTION. A
TROPICAL WAVE IN THE EASTERLY TRADES IS NOW IN PHASE WITH THE TUTT
ALOFT...WITH CONVECTIVE ACTIVITY FLARING UP EARLY THIS MORNING
ACROSS THE LEEWARD ISLANDS. CONVECTIVE CELLS ARE ALSO BUILDING
WEST AHEAD OF THIS WAVE ACROSS THE VIRGIN ISLES TO PUERTO RICO.

AS THE SUBEQUATORIAL RIDGE INTENSIFIES...THE TUTT WILL RELOCATE
ACROSS HISPANIOLA-CENTRAL CARIBBEAN EARLY IN THE CYCLE. THROUGH
FRIDAY AFTERNOON THE RIDGE IS TO GRADUALLY BECOME THE DOMINANT
FEATURE WHILE TROUGH BEGINS TO PULL. AS A RESULT...DIVERGENT
PATTERN ALOFT IS GOING TO BE RELATIVELY BRIEF/SHORT LASTING...WITH
STRONG CAP TO GRADUALLY ESTABLISH THROUGH THE DAY ON THURSDAY TO
EARLY FRIDAY. THIS IS TO THEN SUSTAIN A RAPID EROSION OF AVAILABLE
WATER FOLLOWING THE WAVE PASSAGE.

BEST MOISTURE CONVERGENCE IS EXPECTED ACROSS THE VIRGIN
ISLES-EASTERN PUERTO RICO DURING THE MORNING TO EARLY AFTERNOON
HOURS...WITH PWAT TO PEAK AROUND 50MM. BUT LATER IN THE DAY IT
WILL START TO DROP AT A FAIRLY FAST PACE. AS A RESULT...EXPECTING
MOST ACTIVE CONVECTION WITH APPROACHING WAVE TO DEVELOP ACROSS THE
USVI TO EASTERN PORTIONS OF PUERTO RICO...WITH RAINFALL AMOUNTS TO
PEAK AT 20-45MM. LATE AFTERNOON/EVENING ACTIVITY IS THEN EXPECTED
ACROSS THE CARIBBEAN WATERS OF PUERTO RICO AND POSSIBLY SOUTH
COAST OF THE ISLAND. AS A DRYER AIR MASS ENVELOPS THE FORECAST
AREA...FAIR WEATHER CONDITIONS ARE TO THEN FOLLOW.

MCKENZIE...BDM (BAHAMAS)
ROBINSON...MSJ (JAMAICA)
DAVISON...WPC (USA)
$$

000
FXCA20 KWBC 181811
PMDCA

TROPICAL DISCUSSION - INTERNATIONAL DESKS
NWS WEATHER PREDICTION CENTER COLLEGE PARK MD
211 PM EDT TUE JUN 18 2013

AT 15UTC TROPICAL DEPRESSION TWO CENTERED NEAR 17.9N 90.0W...WITH
CENTRAL PRESSURE OF 1009 HPA AND MAXIMUM SUSTAINED WINDS OF 25KT.
THE DEPRESSION IS MOVING TO THE WEST-NORTHWEST AT 07KT. SEE NHC
FORECAST FOR DETAILS.

DISCUSSION FROM JUNE 18/00UTC: AT 250 HPA...A NARROW TROUGH ACROSS
THE WESTERN GULF OF MEXICO/CENTRAL MEXICO TO A LOW SOUTH OF
GUERRERO SPLITS THE SUBTROPICAL RIDGE IN TWO CELLS. THE
WESTERNMOST EXTENDS ACROSS THE BAJA PENINSULA-NORTHERN STATES OF
MEXICO...WHILE CENTERING ON A CLOSED HIGH NEAR SOUTHERN BAJA
PENINSULA. THE EASTERNMOST EXTENDS ACROSS CENTRAL AMERICA/WESTERN
CARIBBEAN...WHILE CENTERING ON A CLOSED HIGH OVER GUATEMALA.
THROUGH 60-72 HRS THE TROUGH IS FORECAST TO FILL...AND BY THEN THE
RIDGES ARE EXPECTED TO MERGE. MEANWHILE...THE TROUGH ALOFT IS TO
ENHANCE CONVECTIVE DEVELOPMENT ACROSS THE SIERRA MADRE DEL SUR TO
SOUTHERN OAXACA AND CENTRAL PORTIONS OF MEXICO...TO SUSTAIN
RAINFALL AMOUNTS OF 05-10MM/DAY AND MAXIMA OF 15-25MM/DAY. THE
RIDGES...MEANWHILE...ARE TO VENT DEEP CONVECTION ALONG THE SIERRA
MADRE OCCIDENTAL TO FAVOR RAINFALL AMOUNTS OF 00-05MM/DAY AND
MAXIMA OF 10MM.

AT LOW LEVELS...TROPICAL DEPRESSION TWO IS TO TRACK ACROSS
GUATEMALA-SOUTHERN MEXICO TO THE CAMPECHE SOUND. THE NHC FORECASTS
THIS SYSTEM TO REMAIN ILL ORGANIZED AS IT MEANDERS ACROSS THE
SOUTHERN GULF. ACROSS THE YUCATAN IT IS TO FAVOR RAINFALL AMOUNTS
OF 10-15MM/DAY AND MAXIMA OF 20-40MM/DAY THROUGH 36 HRS. OVER
OAXACA-CHIAPAS-CAMPECHE...AS IT INTERACTS WITH TROUGH ALOFT...
EXPECTING RAINFALL AMOUNTS OF 35-70MM/DAY AND MAXIMA OF 75-125MM
THROUGH 36 HRS. BY 36-60 HRS THIS IS TO DECREASE TO 15-20MM/DAY
AND MAXIMA OF 35-70MM...WITH MOST ACTIVE ACROSS SOUTHERN
VERACRUZ-OAXACA TO THE CENTRAL STATES OF MEXICO. THROUGH 72-96 HRS
THIS IS TO CONTINUE DECREASING WITH RAINFALL AMOUNTS OF
10-15MM/DAY AND MAXIMA OF 20-35MM.

THE EASTERN CARIBBEAN REMAINS UNDER INFLUENCE OF A TUTT THAT
EXTENDS SOUTH FROM A CLOSED LOW NORTH OF THE ISLANDS AND ACROSS
PUERTO RICO TO THE BASIN. THE TROUGH IS ENHANCING ITCZ RELATED
CONVECTION ACROSS THE WINDWARD ISLANDS WHILE ALSO INTERACTING WITH
A TROPICAL WAVE PROPAGATING ALONG THE CONVERGENCE ZONE/THE
GUIANAS. PUERTO RICO AND THE USVI...MEANWHILE...LIE ON THE
CONVERGENT/ SUBSIDENT SIDE OF THIS FEATURE. THE TROUGH IS TO HOLD
ITS GROUND DURING THE NEXT 24-36 HRS. BUT BY 48-72 HRS...A
BUILDING CELL OF THE SUBEQUATORIAL RIDGE IS TO DISPLACE THE TUTT
TO THE WEST...WITH AXIS TO RELOCATE TO HISPANIOLA-CENTRAL
CARIBBEAN/NORTHERN COLOMBIA.  AS THE TROUGH PULLS AWAY...
ENVIRONMENTAL CONDITIONS OVER THE NORTHEAST CARIBBEAN ISLES ARE TO
BECOME MORE CONDUCIVE TO DEEP CONVECTION...WITH MODEL GUIDANCE
SHOWING AN UPPER DIVERGENT PATTERN GRADUALLY ESTABLISHING THROUGH
42-48 HRS. ACROSS NORTHERN SOUTH AMERICA THE RETROGRESSING TROUGH
IS TO THEN ENHANCE VENTILATION ALOFT OVER NORTHWEST VENEZUELA TO
NORTHERN COLOMBIA. MOST ACTIVE CONVECTION ACROSS THE ISLAND
CHAIN-NORTHEAST CARIBBEAN ISLANDS WILL DEPEND ON INTERACTION WITH
A TROPICAL WAVE ENTERING THE BASIN (SEE BELOW FOR DETAILS). ACROSS
THE SOUTHERN WINDWARD ISLANDS...AS IT INTERACTS WITH THE
ITCZ...THIS IS TO FAVOR RAINFALL AMOUNTS OF 05-10MM/DAY AND MAXIMA
OF 15-25MM/DAY. OVER NORTHWEST VENEZUELA-NORTHERN COLOMBIA IT IS
TO THEN FAVOR RAINFALL AMOUNTS OF 15-20MM/DAY AND MAXIMA OF
25-50MM AS IT INTERACTS WITH THE NEAR EQUATORIAL TROUGH AND THE
TROPICAL WAVE.

OVER THE EASTERN PACIFIC...THE ITCZ IS TO MEANDER WEST ALONG 10N
ACROSS COSTA RICA/PANAMA TO NORTHERN COLOMBIA. ACROSS WESTERN
PANAMA-COSTA RICA THIS IS TO FAVOR RAINFALL AMOUNTS OF 05-10MM/DAY
AND MAXIMA OF 15-25MM/DAY. OVER EASTERN PANAMA EXPECT ACCUMULATION
OF 00-05MM/DAY AND MAXIMA OF 10MM. OVER NORTHERN COLOMBIA TO
NORTHWEST VENEZUELA EXPECTING RAINFALL AMOUNTS OF 05-10MM/DAY AND
MAXIMA OF 15-25MM/DAY THROUGH 48-60 HRS...AND 15-20MM/DAY AND
MAXIMA OF 25-50MM AS IT INTERACTS WITH THE CARIBBEAN TUTT.

TROPICAL/EASTERLY WAVES INITIALIZED AT 12UTC

INITIAL 24   36   48   60   72   84   TYPE
51W     56W  60W  64W  68W  71W  74W  TW

TROPICAL WAVE IS INITIALIZED ALONG 51W. THIS IS TO QUICKLY
PROPAGATE ACROSS THE GUIANAS TO THE LESSER ANTILLES THROUGH 30-36
HRS. AS IT PHASES WITH THE EASTERN CARIBBEAN TUTT...PWAT IS TO
INCREASE TO 40-50MM IN ASSOCIATION WITH THIS WAVE. THROUGH 42-48
HRS MOISTURE SURGES ACROSS THE VIRGIN ISLES TO EASTERN PUERTO
RICO...AND THROUGH 60-72 HRS THIS WILL EXPAND TO THE DOMINICAN
REPUBLIC. RAPID EROSION OF AVAILABLE MOISTURE IS TO FOLLOW...WITH
PWAT DECREASING TO 30-35MM ON ITS WAKE. OVER NORTHERN GUYANA TO
NORTHEAST VENEZUELA/SOUTHERN WINDWARD ISLANDS IT IS TO THEN RESULT
IN RAINFALL AMOUNTS OF 05-10MM/DAY AND MAXIMA OF 15-25MM/DAY...
WHILE OVER THE LEEWARD/FRENCH ISLANDS EXPECTING ACCUMULATION OF
10-15MM/DAY AND MAXIMA OF 20-40MM/DAY. OVER PUERTO RICO TO THE
DOMINICAN REPUBLIC EXPECTING RAINFALL AMOUNTS OF 10-15MM/DAY AND
MAXIMA OF 20-45MM/DAY. THROUGH 72 HRS THIS DECREASES TO
10-15MM/DAY AND MAXIMA OF 20-35MM AS IT MOVES ACROSS HAITI. LATER
ON DAY 03...TO DAY 04...CONVECTION IS TO SPREAD TO JAMAICA WITH
ACCUMULATION OF 05-10MM/DAY AND MAXIMA OF 15MM. OVER CENTRAL
VENEZUELA...IN INTERACTION WITH THE NEAR EQUATORIAL
TROUGH...EXPECTING RAINFALL AMOUNTS OF 05-10MM/DAY AND MAXIMA OF
15-20MM/DAY...WHILE OVER NORTHWEST VENEZUELA/NORTHERN COLOMBIA IT
IS TO SUSTAIN RAINFALL AMOUNTS OF 15-20MM/DAY AND MAXIMA OF
25-50MM/DAY.

MCKENZIE...BDM (BAHAMAS)
ROBINSON...MSJ (JAMAICA)
DAVISON...WPC (USA)
$$

000
FXCA20 KWBC 181116
PMDCA

TROPICAL DISCUSSION - INTERNATIONAL DESKS
NWS WEATHER PREDICTION CENTER COLLEGE PARK MD
715 AM EDT TUE JUN 18 2013

PRELIMINARY DISCUSSION FOR PUERTO RICO AND THE USVI. FORECAST AREA
REMAINS UNDER INFLUENCE OF A TUTT THAT EXTENDS SOUTH FROM A CLOSED
LOW NORTH OF THE ISLANDS...ACROSS PUERTO RICO TO THE EASTERN
CARIBBEAN. THE TROUGH IS ENHANCING ITCZ RELATED CONVECTION ACROSS
THE WINDWARD ISLANDS WHILE ALSO INTERACTING WITH A TROPICAL WAVE
PROPAGATING ALONG THE CONVERGENCE ZONE/THE GUIANAS. PUERTO RICO
AND THE USVI...MEANWHILE...LIE ON THE CONVERGENT/SUBSIDENT SIDE OF
THIS FEATURE.

BUILDING CELL OF THE SUBEQUATORIAL RIDGE IS TO DISPLACE TUTT TO
THE WEST...WITH AXIS TO RELOCATE TO HISPANIOLA LATER ON WEDNESDAY
EVENING. AS THE TROUGH PULLS AWAY...ENVIRONMENTAL CONDITIONS ARE
TO BECOME MORE CONDUCIVE TO DEEP CONVECTION...WITH MODEL GUIDANCE
SHOWING AN UPPER DIVERGENT PATTERN ESTABLISHING ACROSS THE
NORTHEAST CARIBBEAN ISLANDS. THIS IS TO COINCIDE WITH ARRIVAL OF
TROPICAL WAVE...EXPECTED TO ENTER THE VIRGIN ISLES AROUND 00UTC ON
THURSDAY...CROSSING THE MONA PASSAGE TO EASTERN HISPANIOLA THROUGH
12UTC. AS THEY INTERACT...PWAT IS TO INCREASE TO 40-50MM DURING
THE DAY ON WEDNESDAY. BUT FOLLOWING WAVE PASSAGE THIS IS TO
QUICKLY ERODE AS A LOW LEVEL CAP INVERSION DEVELOPS THROUGH THE
DAY ON THURSDAY.

GLOBAL GUIDANCE DIVERGE ON IMPACT THIS IS GOING TO HAVE ACROSS
FORECAST AREA. THE GFS APPEARS AS THE MOST ACTIVE...WHILE THE
UKMET AND ECMWF APPEAR SOMEWHAT MORE CONSERVATIVE ON THEIR
RAINFALL AMOUNTS. CONSIDERING THE POSITIVE INTERACTION WITH UPPER
TUTT AND EFFECTS OF DAYTIME HEATING...WE ARE LEANING TOWARDS THE
WETTER GFS SOLUTION. AS A RESULT...EXPECTING RAINFALL AMOUNTS OF
10-15MM AND MAXIMA OF 20-45MM...WITH MOST INTENSE TO CLUSTER
ACROSS THE VIRGIN ISLES-EASTERN PUERTO RICO (LUQUILLO TO HUMACAO).
NIGHTTIME CONVECTION IS LIKELY TO THEN AFFECT SOUTH COAST OF
PUERTO RICO AS THE WAVE PULLS ACROSS THE BASIN. IF THE WAVE HAS AS
MUCH VORTICITIY AS THE GFS IS SUGGESTING...CONSIDER POTENTIAL FOR
MCS FORMATION OVER THE MONA PASSAGE DURING EARLY MORNING HOURS ON
THURSDAY.

MCKENZIE...BDM (BAHAMAS)
ROBINSON...MSJ (JAMAICA)
DAVISON...WPC (USA)
$$