166  
FXCA20 KWBC 021520  
PMDCA  
 
TROPICAL DISCUSSION - INTERNATIONAL DESKS  
NWS WEATHER PREDICTION CENTER COLLEGE PARK MD  
1120 AM EDT TUE MAY 02 2023  
 
FORECAST BULLETIN FROM 02 MAY 2023 AT 1620 UTC: THE UPPER  
CONVERGENT PHASE OF MJO WILL CONTINUE TO PERSIST OVER THE AMERICAS  
THROUGH THE WEEKEND...LIMITING THE COVERAGE AND INTENSITY OF DEEP  
CONVECTION AND ASSOCIATED PRECIPITATION. THIS IS CONSISTENT AS  
WELL WITH A STRENGTHENING OF THE EASTERLY TRADES...WHICH WILL  
FAVOR ENHANCED LOW-LEVEL SHEAR AND DRIER-THAN-NORMAL CONDITIONS  
ACROSS MOST OF THE CARIBBEAN AND NORTHERN SOUTH AMERICA.  
 
ZONAL WESTERLY FLOW CONTINUES OVER MEXICO IN THE MID-UPPER  
TROPOSPHERE. THIS IS CLUSTERING MOISTURE TO THE SIERRA MADRE  
ORIENTAL...WHERE EXPECT ISOLATED CONVECTION ON A DAILY BASIS. A  
NEGATIVELY TILTED UPPER TROUGH IS FORECAST TO APPROACH FROM THE  
WEST ON WEDNESDAY AND THURSDAY...TO EXTEND FROM NORTHERN BAJA  
CALIFORNIA INTO WESTERN JALISCO BY THURSDAY EVENING. THIS WILL  
ENHANCE THE ONSHORE TRANSPORT OF MOISTURE FROM THE GULF OF  
MEXICO...FAVORING AN INCREASE IN THE COVERAGE OF DIURNAL  
CONVECTION ON WEDNESDAY AND EXPECIALLY THURSDAY. ON  
WEDNESDAY...EXPECT 05-10MM/DAY AND MAXIMA OF 15MM IN NORTHERN  
COHUILA WITH A SLIGHT RISK FOR SEVERITY. THIS INCREASES TO  
05-10MM/DAY AND MAXIMA OF 15-25MM BY THURSDAY WITH A CONTINUED  
RISK FOR SEVERITY. ALSO ON THURSDAY...EXPECT SCATTERED  
THUNDERSTORMS IN EASTERN PORTIONS OF THE EJE VOLCANICO  
TRANSVERSAL...TO PRODUCE AMOUNTS OF 05-10MM/DAY AND MAXIMA OF  
15-25MM.  
 
A ROBUST CELL OF THE SUBEQUATORIAL RIDGE CENTERS OVER THE CENTRAL  
CARIBBEAN ON TUESDAY MORNING...EXTENDING FROM NORTHERN CENTRAL  
AMERICA INTO SOUTHERN COLOMBIA AND EAST INTO THE LEEWARD ISLANDS.  
THIS COINCIDES WITH AN ELONGATED MID-LEVEL RIDGE THAT CENTERS JUST  
TO THE SOUTH OF HISPANIOLA AND EXTENDS FROM THE YUCATAN PENINSULA  
INTO THE LEEWARD ISLANDS AND NORTHERN SOUTH AMERICA. CENTRAL  
AMERICA LIES ALONG THE SOUTHWEST PERIPHERY OF THESE RIDGES...WHICH  
WILL ALLOW FOR SOME VENTILATION FOR DEVELOPING DEEP CONVECTION  
THROUGH THE FORECAST CYCLE. AN EASTERLY WAVE IS PROPAGATING ACROSS  
NICARAGUA/EL SALVADOR AND HONDURAS ON TUESDAY...SOUTHERN  
GUATEMALA/CHIAPAS ON WEDNESDAY...TO THEN EXIT INTO OPEN WATERS OF  
THE EASTERN PACIFIC. THIS WILL PROVIDE ENHANCEMENT OF DIURNAL  
CONVECTION...TO FAVOR 10-15MM/DAY AND MAXIMA OF 20-45MM IN  
HONDURAS/EL SALVADOR/SOUTHERN GUATEMALA ON TUESDAY...AND MAXIMA OF  
15-30MM IN THE GULF OF FONSECA REGION. TRAILING MOISTURE WILL  
FAVOR 05-10MM/DAY AND MAXIMA OF 15-30MM IN COSTA RICA AND EASTERN  
NICARAGUA...AIDED BY TRADE WIND CONVERGENCE. ON WEDNESDAY...THE  
WAVE WILL FAVOR 10-15MM/DAY AND MAXIMA OF 20-35MM IN  
BELIZE...CENTRAL GUATEMALA AND NORTHWEST HONDURAS...WHERE AMOUNTS  
WILL BE STIMULATED BY THE BASE OF AN UPPER TROUGH. IN SOUTHERN  
GUATEMALA...EL SALVADOR AND CENTRAL/SOUTHERN HONDURAS EXPECT  
05-10MM/DAY AND MAXIMA OF 15-25MM. ON THURSDAY...LINGERING  
MOISTURE WILL FAVOR 05-10MM/DAY AND MAXIMA OF 15MM IN  
GUATEMALA/BELIZE/CHIAPAS. ENHANCED TRADE WIND CONVERGENCE...AS THE  
TRADES ACCELERATE...WILL FAVOR 05-10MM/DAY AND MAXIMA OF 15-25MM  
IN EASTERN COSTA RICA AND NORTHWEST PANAMA.  
 
IN THE CARIBBEAN...THE INFLUENCE OF THE MID-LEVEL RIDGE AND THE  
UPPER CONVERGENT PHASE OF THE MJO WILL CONTINUE LIMITING  
ACCUMULATIONS ACROSS THE ENTIRE BASIN. A SURFACE FRONT IS  
LINGERING ACROSS THE CENTRAL BAHAMAS AND CENTRAL CUBA ON TUESDAY  
WHILE WEAKENING...FAVORING MAXIMA GENERALLY UNDER 10MM/DAY. ON  
WEDNESDAY...THE FRONTOLIZING BOUNDARY WILL FAVOR SIMILAR AMOUNTS  
IN THE CENTRAL BAHAMAS. ANOTHER FRONT ARRIVES INTO THE NORTHWEST  
BAHAMAS EARLY ON THURSDAY. BY THURSDAY EVENING...THE BOUNDARY IS  
FORECAST TO STALL ACROSS THE CENTRAL BAHAMAS...FLORIDA  
STRAIT...WHERE IT WILL START TO WEAKEN. THIS WILL FAVOR MAXIMA  
UNDER 10MM IN THE CENTRAL BAHAMAS AND 05-10MM/DAY AND MAXIMA OF  
15MM IN CUBA. OTHERWISE IN THE CARIBBEAN BASIN...DIURNAL  
THUNDERSTORMS ARE EXPECTED ON A DAILY BASIS IN HISPANIOLA. THIS  
WILL FAVOR 05-10MM/DAY AND ISOLATED MAXIMA OF 15-20MM ON TUESDAY  
AND WEDNESDAY...INCREASING TO MAXIMA OF 15-25MM ON THURSDAY  
ASSOCIATED WITH A PREFRONTAL TROUGH-LIKE STRUCTURE. VERY LIGHT  
CONVECTION IS ALSO EXPECTED IN THE CENTRAL LESSER ANTILLES ON A  
DAILY BASIS.  
 
IN SOUTH AMERICA...A DRY SPELL CONTINUES UNRAVELING IN AREAS TO  
THE NORTH OF 5N...AS A DRY AIR MASS CONTINUES PRESENT OVER THE  
REGION. THE NET HAS MEANDERED SOUTH AND IS FORECAST TO EXTEND  
ACROSS AMAPA AND NORTHERN BRASIL AND EXTEND CLOSE TO THE EQUATOR  
INTO SOUTHERN COLOMBIA THROUGH THE CYCLE. HEAVY-RAIN PRODUCING  
THUNDERSTORMS ARE FORECAST TO ORGANIZE PRIMARILY ALONG AND SOUTH  
OF THE NET...WHILE GENERALLY FAIR WEATHER CONDITIONS CO0NTINUE IN  
THE GUIANAS...VENEZUELA AND THE NORTHERN HALF OF COLOMBIA. WETTER  
CONDITIONS ARE EXPECTED IN THE PACIFIC BASIN OF ECUADOR...WHERE  
ONSHORE FLOW AND ITCZ CONVERGENCE WILL FAVOR 10-15MM/DAY AND  
MAXIMA OF 20-35MM ON TUESDAY...INCREASING TO MAXIMA OF 20-45MM  
THEREAFTER. LOCALLY HIGHER AMOUNTS ARE ALSO EXPECTED IN AMAPA DUE  
TO ITCZ MOISTURE CONVERGENCE.  
 
GALVEZ/ACOSTA/ALAMO...WPC (USA)  
 

 
 
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