164  
FXCA20 KWBC 221837  
PMDCA  
 
TROPICAL DISCUSSION - INTERNATIONAL DESKS  
NWS WEATHER PREDICTION CENTER COLLEGE PARK MD  
236 PM EDT FRI JUN 22 2018  
 
TROPICAL DISCUSSION FROM JUN 22/12 UTC: THERE ARE TWO SYSTEMS OF  
INTEREST IN THE BASIN TO MONITOR THROUGH THE FORECAST CYCLE. ONE  
IS A TUTT LOCATED TO THE EAST OF THE BAHAMAS...WHICH IS FORECAST  
TO INTERACT WITH AN EASTERLY WAVE PROPAGATING ACROSS THE EASTERN  
CARIBBEAN. THE SECOND SYSTEM OF INTEREST IS A TUTT LOCATED OVER  
THE SOUTHERN GULF OF MEXICO...WHICH IS ENHANCING CONVECTION IN THE  
GULF OF HONDURAS AND NORTHERN CENTRAL AMERICA.  
 
IN MEXICO...EARLY IN THE CYCLE...A REGION OF ENHANCED PRECIPITABLE  
WATER IS MEANDERING WESTWARD ACROSS CENTRAL PARTS OF THE COUNTRY.  
THIS WILL FAVOR MODERATE RAINFALL IN SOUTHERN PORTIONS OF THE  
SIERRA MADRE OCCIDENTAL TO PRODUCE 10-15MM/DAY AND MAXIMA OF  
20-35MM IN SINALOA/DURANGO/NAYARIT INTO JALISCO/ZACATECAS ON  
FRIDAY. AMOUNTS WILL DECREASE IN DURANGO AND SINALOA AFTER...AS  
MOIST PLUME MEANDERS WESTWARD INTO THE PACIFIC.  
 
ALSO IN MEXICO AND NORTHERN CENTRAL AMERICA...ACTIVITY IS BEING  
ENHANCED BY A TUTT RETROGRESSING WESTWARD ACROSS THE SOUTHERN GULF  
OF MEXICO. THE TUTT IS FORECAST TO RETROGRESS FROM THE YUCATAN  
PENINSULA ON FRIDAY TO CENTER ACROSS CENTRAL MEXICO BY MONDAY  
THROUGH TUESDAY. THIS WILL LEAD TO A SHIFT IN HEAVIEST  
PRECIPITATION FROM EAST TO WEST THROUGH THE CYCLE. THROUGH EARLY  
SATURDAY...LARGEST ACCUMULATIONS WILL CLUSTER IN OAXACA/CHIAPAS  
INTO CAMPECHE...GUATEMALA...BELIZE AND WESTERN HONDURAS/EL  
SALVADOR...WHERE EXPECTING 15-20MM/DAY AND MAXIMA OF 35-70MM.  
EXPECT SIMILAR AMOUNTS ON SATURDAY-SUNDAY ACROSS EXTREME WESTERN  
HONDURAS/EL SALVADOR INTO WESTERN GUATEMALA AND CHIAPAS/TABASCO.  
IN THE YUCATAN PENINSULA EXPECTING 10-15MM/DAY AND MAXIMA OF  
20-40MM ON BOTH DAYS AS WELL. IN NICARAGUA/EASTERN  
HONDURAS...EXPECTING 10-15MM/DAY AND MAXIMA OF 20-40MM ON  
FRIDAY-SATURDAY DECREASING AFTER. THE DISTRIBUTION OF  
PRECIPITATION WILL CHANGE BY SUNDAY-MONDAY...WHEN EXPECTING THE  
HEAVIEST IN CENTRAL MEXICO TO REACH ACCUMULATIONS OF 15-20MM/DAY  
AND MAXIMA OF 25-50MM. IN WESTERN HONDURAS/EL SALVADOR INTO  
GUATEMALA/CHIAPAS EXPECTING 10-15MM/DAY AND MAXIMA OF 20-40MM. IN  
THE YUCATAN PENINSULA AND NICARAGUA EXPECTING 05-10MM/DAY AND  
MAXIMA OF 15-25MM.  
 
AS A LARGE TUTT EVOLVES AND MEANDERS WESTWARD ACROSS THE ATLANTIC  
NORTH OF PUERTO RICO/HISPANIOLA INTO THE BAHAMAS THROUGH THE  
CYCLE...EXPECTING SCATTERED MODERATE CONVECTION TO CONTINUE IN THE  
GREATER ANTILLES. FURTHERMORE...AN EASTERLY WAVE PROPAGATING  
ACROSS THE EASTERN CARIBBEAN WILL CONTRIBUTE TO ENHANCED MOISTURE  
CONVERGENCE TO SUSTAIN MODERATE PRECIPITATION. A TRADE WIND SURGE  
TRAILS BEHIND THE WAVE. THIS WILL SUSTAIN A GRADUAL DRYING  
STARTING ON THE LESSER ANTILLES ON SATURDAY AND CROSSING PUERTO  
RICO ON SUNDAY. THIS WILL LEAD TO A TRANSITION INTO SCATTERED  
LIGHT TRADE WIND SHOWERS BY EARLY NEXT WEEK...WITH THE EXCEPTION  
OF MODERATE ACCUMULATIONS IN THE REGIONS OF STREAMERS. IN THE MEAN  
TIME...INTERACTION BETWEEN THE WAVE AND THE TUTT WILL LEAD TO  
MODERATE PRECIPITATION IN THE NORTHEASTERN ANTILLES INTO PUERTO  
RICO/DOMINICAN REPUBLIC ON FRIDAY-SATURDAY...WHERE EXPECTING  
15-20MM/DAY AND MAXIMA OF 35-70MM. THIS INCLUDES THE RISK FOR MCS  
FORMATION IN THE VIRGIN ISLANDS/SOUTHEASTERN PUERTO RICO ON  
SATURDAY MORNING. BY SATURDAY-SUNDAY EXPECTING 15-20MM/DAY AND  
MAXIMA OF 30-60MM IN HISPANIOLA AND JAMAICA. THIS INCLUDES THE  
RISK OF MCS FORMATION IN SOUTHEASTERN HISPANIOLA ON SUNDAY  
MORNING. BY SUNDAY-MONDAY...EXPECTING 10-15MM/DAY AND MAXIMA OF  
20-40MM/DAY IN HISPANIOLA AND JAMAICA...UNDER CONTINUED  
ENHANCEMENT BY THE UPPER TROUGH.  
 
SCATTERED CONVECTION IN CUBA AND THE BAHAMAS WILL INCREASE IN  
INTENSITY GRADUALLY AS THE CYCLE PROGRESSES...UNDER THE INFLUENCE  
OF THE APPROACHING TUTT. THIS WILL LEAD TO 05-10MM/DAY AND MAXIMA  
OF 15-20MM THROUGH EARLY SATURDAY...GRADUALLY INCREASING TO  
10-15MM/DAY AND MAXIMA OF 20-35MM BY SUNDAY-MONDAY.  
 
IN NORTHERN SOUTH AMERICA...CONVECTION WILL ORGANIZE MOSTLY ALONG  
THE ITCZ/NET WHICH IS MEANDERING ACROSS THE GUIANAS INTO VENEZUELA  
AND NORTHERN COLOMBIA...PANAMA. EAST ACROSS THE GUIANAS...DAILY  
ITCZ/TRADE WIND CONVERGENCE WILL SUSTAIN ENHANCED ACTIVITY ALONG  
COASTAL AREAS. AN INCREASE IS EXPECTED ON SUNDAY-MONDAY IN  
ASSOCIATION WITH A DISORGANIZED TROPICAL WAVE ARRIVING FROM THE  
ATLANTIC. EXPECTING AMOUNTS OF 10-15MM/DAY AND MAXIMA OF  
20-30MM/DAY THROUGH SATURDAY...INCREASING TO 15-20MM/DAY AND  
MAXIMA OF 25-50MM BY SATURDAY-SUNDAY. BY SUNDAY-MONDAY...EXPECTING  
15-20MM/DAY AND MAXIMA OF 25-50MM CLUSTERING IN NORTHERN  
GUYANA/NORTHEASTERN VENEZUELA AND TRINIDAD AND TOBAGO. ALSO IN  
NORTHERN SOUTH AMERICA...CONVECTION ALONG/SOUTH OF THE NET WILL  
CONTINUE ENHANCED BY OROGRAPHY ACROSS CENTRAL/SOUTHERN VENEZUELA.  
INITIALLY...THIS WILL LEAD TO 15-20MM/DAY AND MAXIMA OF 25-50MM  
THROUGH EARLY SUNDAY. AS THE SUBTROPICAL RIDGE IN CENTRAL SOUTH  
AMERICA STRENGTHENS INTO EARLY NEXT WEEK...ENHANCED VENTILATION  
WILL LEAD TO AN INCREASE IN ACCUMULATIONS TO SUSTAIN 15-20MM/DAY  
AND MAXIMA OF 35-70MM.  
 
IN COLOMBIA AND SOUTHERN CENTRAL AMERICA...ACTIVITY WILL BE  
SENSITIVE TO EASTERLY WAVE PROPAGATING INTO THE REGION AND THE  
INFLUENCE OF THE ITCZ/NET. ALSO...AS TRADE WINDS INCREASE IN THE  
CARIBBEAN INTO EARLY NEXT WEEK...EXPECTING A DECREASE IN  
ACCUMULATIONS IN EXTREME NORTHERN COLOMBIA AND AN INCREASE IN  
EASTERN COSTA RICA AND THE EJE CAFETERO/NORTHWESTERN COLOMBIA.  
THROUGH EARLY SATURDAY EXPECTING AMOUNTS OF 10-15MM/DAY AND MAXIMA  
OF 20-30MM IN PANAMA AND COSTA RICA...AND EXTREME NORTHERN  
COLOMBIA/LAKE MARACAIBO REGION. THIS WILL DECREASE ON  
SATURDAY-SUNDAY IN COLOMBIA...WHILE INCREASING TO 10-15MM/DAY AND  
MAXIMA OF 20-45MM IN COSTA RICA/SOUTHERN NICARAGUA. BY  
SUNDAY-MONDAY...EXPECTING 15-20MM/DAY AND MAXIMA OF 25-50MM  
STRETCHING FROM NORTHWESTERN COLOMBIA INTO PANAMA AND COSTA RICA.  
 
TROPICAL/EASTERLY WAVES/TRADE WIND SURGES FROM 00 UTC:  
INITIAL 24 36 48 60 72 84 96 TYPE SOF  
36W 41W 46W 51W 56W 60W 65W 70W TW 12N  
48W 53W 58W 63W 68W 73W 78W 83W TW 11N  
68W 72W 76W 79W 83W 86W 90W 93W EW 19N  
81W 83W 86W 89W 92W DISSIPATES EW 17N  
 
A TROPICAL WAVE ALONG 36W AND SOUTH OF 11N IS ILL-DEFINED AS IT  
PROPAGATES ALONG THE ATLANTIC ITCZ. THIS WAVE IS FORECAST TO ENTER  
FRENCH GUIANA LATE ON SATURDAY...TO TRIGGER RAINFALL AMOUNTS OF  
10-15MM/DAY AND MAXIMA OF 20-30MM. AS IT APPROACHES  
GUYANA/NORTHEAST VENEZUELA/TRINIDAD AND TOBAGO ON SUNDAY...IT WILL  
FAVOR 15-20MM/DAY AND MAXIMA OF 25-50MM.  
 
A TROPICAL WAVE ALONG 48W AND TO THE SOUTH OF 12N REACHES FRENCH  
GUIANA LATER ON FRIDAY...WHERE IT IS TO FAVOR RAINFALL AMOUNTS OF  
10-15MM/DAY AND MAXIMA OF 20-30MM. SIMILAR AMOUNTS ARE EXPECTED  
ACROSS SURINAME TO GUYANA. OVER THE WINDWARD ISLANDS EXPECTING  
LIGHT RAINFALL AMOUNTS IN ISOLATED CONVECTION. MOST ACTIVE IS  
EXPECTED OVER VENEZUELA ON SATURDAY ALONG THE NET WITH  
ACCUMULATION OF 15-20MM/DAY AND MAXIMA OF 25-50MM.  
 
AN EASTERLY WAVE IS CROSSING THE EASTERN CARIBBEAN...AND WILL LEAD  
TO MODERATE PRECIPITATION WHILE IT INTERACTS WITH A TUTT TO THE  
NORTH. THIS WILL LEAD TO ENHANCEMENT IN THE NORTHEASTERN ANTILLES  
AND PUERTO RICO/EASTERN DOMINICAN REPUBLIC ON  
FRIDAY-SATURDAY...WHERE IT WILL FAVOR 15-20MM/DAY AND MAXIMA OF  
35-70MM AND THE RISK FOR MCS FORMATION. BY SATURDAY-SUNDAY IT WILL  
FAVOR 15-20MM/DAY AND MAXIMA OF 30-60MM OVER HISPANIOLA AND  
JAMAICA...WITH CONTINUED RISK FOR MCS FORMATION. ALSO ON  
SATURDAY-SUNDAY...CONVECTION AHEAD OF THE WAVE WILL LEAD TO  
10-15MM/DAY AND MAXIMA OF 20-45MM IN COSTA RICA. BY  
SUNDAY-MONDAY...THIS WILL LEAD TO 05-10MM/DAY AND 15-25MM IN  
NORTHEASTERN NICARAGUA/EASTERN HONDURAS...AND 15-20MM/DAY AND  
MAXIMA OF 25-50MM IN COSTA RICA.  
 
AN EASTERLY WAVE ALONG 81W WILL LEAD TO A SLIGHT INCREASE SOUTHERN  
CENTRAL AMERICA EARLY IN THE CYCLE...TO SUSTAIN MAXIMA OF 20-40MM  
IN NICARAGUA/EASTERN HONDURAS...AND 20-30MM IN PANAMA AND COSTA  
RICA. IT WILL THEN LOSE DEFINITION AS IT EXITS INTO THE PACIFIC.  
 
HUDSON...MS (JAMAICA)  
WARD-FORBES...BDM (THE BAHAMAS)  
DAVISON/GALVEZ...WPC (USA)  
 

 
 
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