392
FXCA20 KWBC 241518
PMDCA

TROPICAL DISCUSSION - INTERNATIONAL DESKS
NWS WEATHER PREDICTION CENTER COLLEGE PARK MD
1117 AM EDT FRI MAY 24 2013

DISCUSSION FROM MAY 24/00UTC: ACROSS MEXICO...SEASONAL DIURNAL
MOIST CONVECTION IS RECURRENTLY ESTABLISHING OVER THE MOUNTAINS OF
CENTRAL...SOUTHERN MEXICO AND THE SIERRA MADRE ORIENTAL. AT UPPER
LEVELS...A TROUGH IS AMPLIFYING TO THE WEST WHILE A RIDGE
DOMINATES OVER THE GULF OF MEXICO/YUCATAN. AREAS OF UPPER
CONVERGENCE ASSOCIATED WITH THE RIDGE ARE ENHANCING SUBSIDENCE AND
LEADING TO SEASONALLY QUIET PATTERN OVER THE GULF OF
MEXICO/YUCATAN. UPPER TROUGH TO THE WEST WILL HOWEVER AID
CONVECTIVE DEVELOPMENT ACROSS THE CENTRAL AND SOUTHERN MOUNTAINS
OF MEXICO THROUGH THE CYCLE WITH ACCUMULATIONS IN THE 15-20MM/DAY
RANGE. THROUGH THE CYCLE...EXPECTING STRONGEST/PERSISTENT
AFTERNOON/EVENING CONVECTION ALONG THE EJE VOLCANICO/CENTRAL
MEXICO FROM JALISCO INTO PUEBLA/TLAXCALA...AND OVER THE SIERRA
MADRE DEL SUR. ACROSS NORTHEASTERN MEXICO...A SHORT WAVE TROUGH IS
ENHANCING CONVECTION WITH ACCUMULATIONS OF 10-15MM/DAY AND MAXIMA
OF 20-40MM. A DECREASING TREND IS EXPECTED AS UPPER TROUGH PASSES
BY.

OVER CENTRAL AMERICA...ACTIVE PATTERN OF CONVECTION WILL PERSIST
AND INTENSIFY ACROSS MOUNTAIN AREAS AND ESPECIALLY THE PACIFIC
BASIN. AT MID/UPPER LEVELS...RIDGE CENTERS OVER OAXACA IN MEXICO.
THE RIDGE WILL MEANDER INTO CAMPECHE THROUGH THE CYCLE AS UPPER
TROUGH PUSHES IN FROM THE WEST. ALTHOUGH PRESENT...SUBSIDENCE IS
LIMITED OVER CENTRAL AMERICA AND THE TEMPERATURE INVERSION WEAK.
STRONGER SUBSIDENCE REMAINS TO THE NORTHEAST OF RIDGE AXIS OVER
YUCATAN AND THE SOUTHERN GULF OF MEXICO. AT LOW LEVELS...DEEPEST
MOISTURE POOL AND CONVECTIVE INSTABILITY ARE ESTABLISHED ALONG THE
PACIFIC COAST FROM PENINSULA DE AZUERO/SOUTHERN COSTA RICA INTO
SOUTHERN OAXACA/CHIAPAS/GUATEMALA. WITH THE EXCEPTION OF A LIGHT
NICARAGUA JET...THE TRADES ARE PARTICULARLY WEAK. THIS WILL AID
THE INLAND PENETRATION OF SEA BREEZES FROM THE
PACIFIC...SUSTAINING VERY ACTIVE DIURNAL CONVECTION DURING THE
COMING DAYS. EXPECTING STORMS IN THE MOUNTAINS/WESTERN SLOPES
DURING THE AFTERNOON/EARLY EVENINGS THEN PROPAGATING INTO AREAS
ALONG THE PACIFIC COAST DURING THE EVENING INTO THE EARLY MORNING.
FURTHERMORE...ARRIVING EASTERLY WAVE WILL AID CONVECTION ON DAY 01
ACROSS COSTA RICA...AND ON DAYS 02-03 ACROSS NORTHERN CENTRAL
AMERICA. THROUGH 36 HRS...EXPECTING HEAVIEST ACCUMULATIONS ACROSS
CHIAPAS/GUATEMALA INTO EL SALVADOR/SOUTHWESTERN HONDURAS WITH
AMOUNTS OF 10-15MM/DAY AND MAXIMA OF 20-45MM. OVER COSTA
RICA/WESTERN PANAMA EXPECTING ALSO ACTIVE CONVECTION AND LOCALLY
HEAVY RAINFALL WITH ACCUMULATIONS OF 15-20MM/DAY AND MAXIMA OF
30-60MM. ON DAY 02...EXPECTING HEAVIEST TO CLUSTER ACROSS COSTA
RICA INTO WESTERN NICARAGUA WITH ACCUMULATIONS OF 15-20MM/DAY AND
MAXIMA OF 25-50MM. ACTIVE CONVECTION WILL CONTINUE ACROSS
GUATEMALA/CHIAPAS WITH ACCUMULATIONS OF 10-15MM/DAY AND MAXIMA OF
20-30MM. ON DAY 03...STRONGEST CONVECTION WILL BUILD UP OVER
NORTHWESTERN NICARAGUA/HONDURAS/EL SALVADOR/SOUTHERN GUATEMALA
WITH ACCUMULATIONS OF 15-20MM/DAY AND MAXIMA OF 35-70MM.

OVER THE CARIBBEAN BASIN...TWO DOMINANT FEATURES ARE IN PLACE. AN
UPPER TROUGH IS DIGGING FROM THE SOUTHEASTERN USA AND WILL MOVE
EASTWARD THROUGH THE CYCLE ENHANCING CONVECTION TO ITS EAST AND
SOUTHEAST. THE SECOND FEATURE OF INTEREST IS A REGION OF ENHANCED
TRADE WIND CONVERGENCE AND PRECIPITABLE WATER ACROSS THE LEEWARD
ISLANDS INTO PUERTO RICO...HISPANIOLA...JAMAICA. THE INTERACTION
BETWEEN THE UPPER TROUGHS AND THIS PERSISTENT REGION OF HIGH
MOISTURE/LOW-LEVEL CONVERGENCE WILL ESTABLISH A RATHER PROLONGED
MOIST PATTERN ACROSS THE LEEWARD ISLANDS...PUERTO RICO INTO
HISPANIOLA. ACTIVE CONVECTION WILL ALSO DOT JAMAICA...SOUTHEASTERN
CUBA AND THE SOUTHEASTERN BAHAMAS. ON DAY 01...HEAVIEST
ACCUMULATIONS ARE EXPECTED OVER HISPANIOLA WHERE EXPECTING
15-20MM/DAY AND MAXIMA OF 25-50MM. LOCALLY HEAVY AMOUNTS ARE ALSO
EXPECTED ACROSS THE SOUTHEASTERN BAHAMAS/TURKS AND CAICOS AND
JAMAICA/SOUTHEASTERN CUBA UNDER INFLUENCE OF INDUCED LOW-LEVEL
TROUGH. IN THESE REGIONSEXPECTING ACCUMULATIONS OF 05-10MM/DAY
AND MAXIMA OF 15-30MM. OVER JAMAICA EXPECTING 10-15MM/DAY AND
MAXIMA OF 20-45MM. OVER PUERTO RICO...EXPECTING ACCUMULATIONS OF
10-15MM/DAY AND MAXIMA OF 20-45MM AS MOIST AND UNSTABLE AIRMASS IS
ADVECTED IN FROM THE LEEWARD ISLANDS. ON DAY 02...EXPECTING
HEAVIEST ACROSS PUERTO RICO AND THE DOMINICAN REPUBLIC WITH
ACCUMULATIONS OF 15-30MM/DAY AND ISOLATED MAXIMA OF 50-100MM. ON
DAY 03...MODERATE TO STRONG CONVECTION WILL DEVELOP FROM THE
FRENCH ANTILLES INTO THE SOUTHEASTERN BAHAMAS/HAITI. EXPECTING
HEAVIEST OVER HISPANIOLA AND PUERTO RICO WITH ACCUMULATIONS OF
15-30MM/DAY AND MAXIMA OF 40-80MM. OVER THE FRENCH
ANTILLES/LEEWARD ISLANDS EXPECTING 10-15MM/DAY AND MAXIMA OF
20-40MM.

OVER NORTHWESTERN SOUTH AMERICA...SEASONALLY ENHANCED CONVECTION
WILL CONTINUE. A SLIGHT DECREASE WITH RESPECT TO PREVIOUS DAYS IS
EXPECTED OVER COLOMBIA DURING DAY 01. THIS IS ESPECIALLY TRUE FOR
EXTREME NORTHERN AND EASTERN COLOMBIA AS A DRY AIR MASS IS BEING
ADVECTED FROM VENEZUELA. ON DAY 02...EXPECTING A REACTIVATION
ACROSS EASTERN COLOMBIA AS TROPICAL WAVE ARRIVES FROM THE EAST. ON
DAY 03 TROPICAL WAVE WILL ENHANCE ACCUMULATIONS OVER MOST REGIONS
TO THE SOUTH OF 08N. ACROSS THE PACIFIC BASIN...ENHANCED ONSHORE
FLOW WILL ALSO PRODUCE LOCALLY HEAVY RAINFALL ON DAY 03. IN TERMS
OF ACCUMULATIONS EXPECTING 05-10MM/DAY AND ISOLATED MAXIMA OF
15-30MM. ON DAY 02...EXPECTING ACCUMULATIONS OF 10-15MM/DAY AND
MAXIMA OF 20-45MM OVER NORTHWESTERN COLOMBIA/ANDES. EXPECTING
10-15MM/DAY AND MAXIMA OF 20-40MM ACROSS EASTERN COLOMBIA/SOUTHERN
VENEZUELA. ON DAY 03 EXPECTING HEAVIEST ACROSS WESTERN COLOMBIA
WITH AMOUNTS OF 15-20MM/DAY AND MAXIMA OF 35-70MM. ACROSS NORTHERN
COLOMBIA EXPECTING MAXIMA OF 25-50MM ON DAY 03.

OVER NORTHEASTERN SOUTH AMERICA AND THE WINDWARD ISLANDS...QUIET
PATTERN WILL CHANGE AS TROPICAL WAVE ARRIVES FROM THE EAST. THE
FIRST TROPICAL WAVE TO ARRIVE IS LOSING DEFINITION UNDER
INTERACTION WITH MID-LEVEL RIDGE OVER THE AREA. THE WAVE ARRIVING
INTO THE WINDWARDS LATE ON DAY 02 WILL HAVE A STRONGER IMPACT IN
PRECIPITATION AS IT IS ACCOMPANIED BY A VERY MOIST AND UNSTABLE
AIR MASS. ON DAY 01...EXPECTING HEAVIEST ACROSS COASTAL GUIANAS
WITH ACCUMULATIONS OF 10-15MM/DAY AND MAXIMA OF 20-30MM. ON DAY
02...SCATTERED DEEP CONVECTION SHOULD MOVE INTO EASTERN VENEZUELA
WITH SIMILAR ACCUMULATIONS. ON DAY 03...EXPECTING ENHANCED DEEP
CONVECTION TO EXTEND OVER NORTHEASTERN VENEZUELA AND THE WINDWARD
ISLANDS PRODUCING ACCUMULATIONS OF 10-15MM/DAY AND MAXIMA OF
20-30MM.

TROPICAL/EASTERLY WAVES INITIALIZED AT 12UTC

INITIAL 24   36   48   60   72   84   TYPE
47W     51W  54W  58W  61W  64W  68W  TW
55W     59W  63W  67W  70W  73W  76W  TW
84W     86W  89W  91W  93W  95W  97W  EW

A WELL DEFINED TROPICAL WAVE IS INITIALIZED AT 48W. THIS WAVE IS
ACCOMPANIED BY A MOISTURE SURGE. THE WAVE WILL ENHANCE CONVECTION
AND ACCUMULATIONS ACROSS THE NORTHERN GUIANAS ON DAYS 01 AND 02...
AND OVER THE WINDWARD ISLANDS/NORTHEAST VENEZUELA ON DAY 03.

TROPICAL WAVE ALONG 55W IS LOSING DEFINITION WHILE ENTERING SOUTH
AMERICA. STILL...THIS WAVE WILL ENHANCE ACCUMULATIONS ACROSS THE
GUIANAS TODAY...BUT ESPECIALLY OVER CENTRAL/SOUTHERN VENEZUELA ON
DAY 02...AND EASTERN/CENTRAL COLOMBIA ON DAY 03.

AN EASTERLY WAVE ALONG 84W WILL ENHANCE ACCUMULATIONS ACROSS
CENTRAL AMERICA THROUGH THE CYCLE. STRONGEST CONVECTION IS
EXPECTED OVER COSTA RICA ON DAY 01. ON DAY 02 FOCUS WILL MOVE TO
NORTHERN COSTA RICA/NICARACUA/SOUTHERN HONDURAS. ON DAY 03
HEAVIEST ACCUMULATIONS WILL EXTEND ACROSS WESTERN
NICARAGUA/HONDURAS/EL SALVADOR AND SOUTHERN GUATEMALA.

BLENMAN...BMS (BARBADOS)
MCKENZIE...BDM (BAHAMAS)
DAVISON/GALVEZ...WPC (USA)

BLENMAN...BMS (BARBADOS)
MCKENZIE...BDM (BAHAMAS)
DAVISON/GALVEZ...WPC (USA)

$$