887  
FXCA20 KWBC 171507  
PMDCA  
 
TROPICAL DISCUSSION - INTERNATIONAL DESKS  
NWS WEATHER PREDICTION CENTER COLLEGE PARK MD  
1006 AM EST TUE DEC 17 2024  
 
FORECAST BULLETIN 17 DEC 2024 AT 1500 UTC:  
 
THE CONVERGENCE PHASES OF THE MADDEN-JULIAN OSCILLATION (MJO) OVER  
THE CARIBBEAN...WILL CONTINUE FAVORING A DRY PERIOD OVER THE  
TROPICAL BASIN.  
 
BY WEDNESDAY...  
 
IN NORTHERN AND EASTERN MEXICO...AN UPPER-LEVEL TROUGH IS EXPECTED  
TO AFFECT PRECIPITATION PATTERNS IN THE REGION OVER THE NEXT FEW  
DAYS. THE COLD FRONT EXTENDING INTO NORTHERN COAHUILA AND NUEVO  
LEON WILL FAVOR ISOLATED THUNDERSTORMS DURING THE EVENING IN  
BELIZE...EASTERN MEXICO...INCLUDING TAMAULIPAS... VERACRUZ AND THE  
YUCATAN PENINSULA...  
 
A LARGE AREA OF HIGH PRESSURE IS GENERATING STRONG NORTHEAST TO  
EAST WINDS IN THE EASTERN GULF OF MEXICO. AN ATLANTIC OCEAN TROUGH  
EXTENDS FROM SOUTHWEST CUBA.  
 
OVER THE NORTHERN CARIBBEAN...A ZONAL SPEED DIVERGENCE... ALONG  
WITH A SURFACE TROUGH MOVING WITH THE EASTERLY FLOW... WILL BRING  
AN INCREASE IN MOISTURE INTO THE NORTHEASTERN REGION OF THE  
DOMINICAN REPUBLIC AND PUERTO RICO...POTENTIALLY TRIGGERING  
ISOLATED THUNDERSTORMS. OVER THE GREATER ANTILLES... A MAXIMUM  
PRECIPITATION OF 15-25 MM IS EXPECTED IN THE LESSER ANTILLES.  
 
IN CENTRAL AMERICA...A TROUGH ALONG THE COAST OF HONDURAS...  
EXTENDING TO THE YUCATAN PENINSULA... COULD GENERATE SOME COASTAL  
SHOWERS DURING THE AFTERNOON.  
 
IN TROPICAL SOUTH AMERICA...FLOW PARALLEL TO THE ANDES IN EASTERN  
COLOMBIA AND ECUADOR... COMBINED WITH MOISTURE CONVERGENCE AND  
DIFFLUENCE AT UPPER LEVELS OVER THE REGION... WILL ENHANCE  
PRECIPITATION... WITH MAXIMUM AMOUNTS EXPECTED THROUGH WEDNESDAY  
AFTERNOON REACHING 15-20 MM. THE NORTHERN PART OF BRAZIL CAN  
EXPECT MAXIMUMS OF 15-25 MM. THE NET/ITCZ WILL CONTINUE TO  
INFLUENCE PRECIPITATION PATTERNS IN THE GUIANAS... WITH MAXIMUMS  
OF 15 MM OVER GUYANA AND SURINAME... AND 15-30 MM OVER FRENCH  
GUIANA.  
 
BY THURSDAY...  
 
IN NORTHERN AND EASTERN MEXICO...AS MENTIONED ABOVE... THE  
UPPER-LEVEL TROUGH AND THE COLD FRONT EXTENDING INTO NORTHERN  
COAHUILA AND NUEVO LEON WILL FAVOR MAXIMUM RAINFALL TOTALS OF  
15-25 MM IN EASTERN MEXICO (TAMAULIPAS AND VERACRUZ).  
 
IN CENTRAL ATLANTIC... AS A LOW-PRESSURE SYSTEM FORMS ON WEDNESDAY  
EVENING INTO THURSDAY MORNING...MOISTURE WILL BEGIN TO ENTER THE  
CARIBBEAN...IN ADDITION TO THE PREVIOUSLY MENTIONED UPPER-LEVEL  
DIVERGENCE. THIS WILL INCREASE PRECIPITATION CHANCES IN THIS  
REGION...WITH MAXIMUM RAINFALL TOTALS OF 15-25 MM IN THE GREATER  
ANTILLES.  
 
IN THE NORTHERN BAHAMAS...THE AFOREMENTIONED UPPER-LEVEL TROUGH  
AND ASSOCIATED COLD FRONT WILL BEGIN IMPACTING THE REGION STARTING  
ON THURSDAY MORNING.  
 
IN CENTRAL AMERICA...A TROUGH ALONG THE COAST OF HONDURAS...  
EXTENDING TO THE YUCATAN PENINSULA... ALONG WITH A SLIGHT INCREASE  
IN MOISTURE...COULD ENHANCE THE PROBABILITY OF PRECIPITATION OVER  
NORTHWEST HONDURAS AND BELIZE. A MAXIMUM PRECIPITATION OF 15-25 MM  
IS EXPECTED.  
 
IN TROPICAL SOUTH AMERICA...MOISTURE CONVERGENCE IN FAR EASTERN  
COLOMBIA...NORTHWESTERN BRAZIL...AND SOUTHERN VENEZUELA WILL  
ASSIST IN ENHANCING PRECIPITATION TOTALS IN THIS REGION.  
MEANWHILE..THE NET/ITCZ WILL CONTINUE TO INFLUENCE PRECIPITATION  
PATTERNS IN THE GUIANAS... WITH MAXIMUM OF 15-25 MM.  
 
BY FRIDAY ...  
 
THE AFOREMENTIONED COLD FRONT WILL CONTINUE TO DRIFT SOUTHWARD  
INTO VERACRUZ AND WEAKENING IN THIS REGION. ENHANCED NORTHERLY  
FLOW IN THE WEST GULF OF MEXICO AND INTO SOUTHERN VERACRUZ WILL  
INDUCE SOME MOISTURE POOLING. RAINFALL TOTALS WILL RANGE FROM 15 -  
20MM IN SOUTHERN VERACRUZ AND TABASCO.  
 
IN THE CARIBBEAN ... THE COLD FRONT WILL CONTINUE TO INFLUENCE  
PRECIPITATION PATTERNS IN THE NORTHWEST BAHAMAS. IN ADDITION ...  
AN UPPER LEVEL SHORTWAVE TROUGH ... 500HPA VORTICITY ADVECTION ...  
AND LOW LEVEL SOUTH/SOUTHEASTERLY FLOW WILL HELP DRIVE IN MORE  
MOISTURE INTO THE REGION AND ENHANCING THE POTENTIAL FOR  
CONVECTION WITH MAXIMUM RAINFALL TOTALS OF 15 - 25MM.  
 
ELSEWHERE IN THE CARIBBEAN ... AN INDUCED TROUGH FROM  
AFOREMENTIONED MID ATLANTIC LOW AND THE EASTERLY TRADES WILL  
ENHANCE MOISTURE FLOW INTO THE LESSER ANTILLES ... THUS INCREASING  
THE POTENTIAL FOR RAINFALL.  
 
IN TROPICAL SOUTH AMERICA AND CENTRAL AMERICA ... THE PANAMIAN LOW  
WILL CONTINUE TO DRIVE IN MOISTURE INTO THE PACIFIC COAST OF  
COLOMBIA WHERE RAINFALL TOTALS WILL BE 20 - 45MM. ELSEWHERE IN  
COLOMBIA ... DRY AIR INTRUSION INTO FROM THE NORTH AND EAST INTO  
CENTRAL COLOMBIA WILL HELP POOL MOISTURE ALONG THE COLOMBIA ...  
VENEZUELA ... BRAZIL BORDER. RAINFALL TOTALS WILL RANGE FROM 20 -  
35MM.  
 
IN CENTRAL AMERICA...ANOTHER REGION OF INTEREST IN COSTA RICA AND  
PANAMA ... WHERE SOME MOISTURE TRANSPORT FROM THE CARIBBEAN AND A  
NEARBY TROUGH WILL LIKELY ENHANCE THE POTENTIAL FOR PRECIPITATION  
IN THE REGION ... WHERE VALUES MAY RANGE FROM 15 - 25MM.  
 
TINOCO...(WPC)  
LEDESMA... (WPC)  
 
 
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