989  
FXCA20 KWBC 021815  
PMDCA  
 
TROPICAL DISCUSSION - INTERNATIONAL DESKS  
NWS WEATHER PREDICTION CENTER COLLEGE PARK MD  
215 PM EDT THU NOV 02 2017  
 
TROPICAL DISCUSSION FROM NOV 02/12 UTC: AN UPPER LEVEL HIGH OVER  
CENTRAL MEXICO EXTENDS A RIDGE EAST ACROSS CENTRAL AMERICA-GREATER  
ANTILLES/CARIBBEAN TO NORTHERN SOUTH AMERICA. THIS SUSTAINS A  
FAIRLY STRONG TRADE WINDS CAP ACROSS HISPANIOLA-PUERTO RICO-LESSER  
ANTILLES...INHIBITING ORGANIZED DEEP CONVECTION. SUCCESSIVE POLAR  
PERTURBATIONS STREAMING ACROSS THE USA TO THE WESTERN ATLANTIC ARE  
TO PRESS AGAINST THIS RIDGE. UNDER PRESSURE...THE PORTION OVER THE  
GREATER ANTILLES/ CARIBBEAN BASIN IS TO COLLAPSE LATER ON  
FRIDAY/EARLY MORNING HOURS ON SATURDAY. REMAINING SEGMENT OVER  
MEXICO IS TO THEN BUILD NORTH INTO THE CENTRAL/WESTERN USA.  
THIS...IN-TURN...IS TO THEN INDUCE THE SOUTHWARD AMPLIFICATION OF  
A LONG WAVE TROUGH ACROSS THE FLORIDA PENINSULA-CUBA TO THE  
WESTERN CARIBBEAN/NORTHERN HONDURAS. AS THE RIDGE WEAKENS TO THE  
EAST...TRADE WINDS CAP OVER THE EASTERN CARIBBEAN ISLES GRADUALLY  
RELAXES ITS FOOTHOLD. THIS IS TO THEN ALLOW FOR DEEPER MOISTURE TO  
POOL ACROSS THE ISLAND CHAIN TO PUERTO RICO/VIRGIN ISLES DURING  
THE WEEKEND. DOWNSTREAM FROM THE UPPER LEVEL RIDGE...A TUTT  
EXTENDS SOUTH ALONG 30N 54W TO THE NORTHERN GUIANAS. AS THE RIDGE  
TO THE WEST FLATTENS THE TUTT IS TO ALSO WEAKEN.  
 
AT LOW LEVELS...A RIDGE EXTENDS TO THE SOUTH-SOUTHWEST ACROSS THE  
EASTERN USA TO THE GULF OF MEXICO. UNDER INFLUENCE OF THE TUTT  
EAST OF THE ISLANDS...AND INVERTED TROUGH EXTENDS NORTH BETWEEN  
50W-60W TO 40N. UNDER INFLUENCE OF THIS TROUGH AND THE RIDGE TO  
THE WEST A LONG FETCH NORTHEASTERLY FLOW DOMINATES THE LEEWARD  
ISLES-PUERTO RICO-HISPANIOLA. THIS FAVORS A COOL ADVECTIVE PATTERN  
ACROSS THE NORTHEAST CARIBBEAN ISLES. AS THE TROUGH ALOFT  
WEAKENS...THE LOW LEVEL PERTURBATION IS TO THEN MEANDER  
WEST...CROSSING 60W INTO THE EASTERN CARIBBEAN LATER ON FRIDAY. IN  
RESPONSE TO THIS FEATURE THE LOW LEVEL WINDS ACROSS THE EASTERN  
CARIBBEAN ARE TO THEN VEER TO THE SOUTHEAST. THIS WILL COINCIDE  
WITH WEAKENING OF TRADE WINDS CAP TO SUSTAIN THE ADVECTION OF A  
PLUME OF DEEP TROPICAL MOISTURE ACROSS THE LESSER ANTILLES ON  
FRIDAY...REACHING PUERTO RICO ON SATURDAY. PWAT CONTENT IS TO THEN  
PEAK AROUND 50MM ON SATURDAY-MONDAY. OVER THE WINDWARD ISLANDS THE  
PLUME OF MOISTURE IS TO SUSTAIN RAINFALL AMOUNTS OF 05-10MM/DAY  
AND MAXIMA OF 15MM. ON SATURDAY THIS IS TO SPREAD ACROSS THE  
LEEWARD-VIRGIN ISLES TO SUSTAIN RAINFALL AMOUNTS OF 10-15MM/DAY  
AND MAXIMA OF 20-30MM IN DEEP CONVECTION. OVER PUERTO RICO AND THE  
DOMINICAN REPUBLIC THIS IS TO ALSO TRIGGER RAINFALL AMOUNTS OF  
10-15MM/DAY AND MAXIMA OF 20-35MM ON SUNDAY.  
 
FARTHER WEST...A WANING SURFACE FRONT EXTENDS ACROSS THE  
BAHAMAS-CUBA TO THE WESTERN CARIBBEAN. LACKING UPPER LEVEL SUPPORT  
THIS BOUNDARY WEAKENS TO AN OPEN TROUGH ON FRIDAY. AS THE FRONT  
WEAKENS A PLUME OF MOISTURE IS TO SPREAD ACROSS THE WESTERN  
CARIBBEAN TO BELIZE-NORTHERN GUATEMALA EARLY ON FRIDAY. INITIALLY  
EXPECTING RAINFALL AMOUNTS OF 10-15MM/DAY AND MAXIMA OF 20-40MM.  
ON FRIDAY TO SATURDAY IT IS TO THEN SUSTAIN RAINFALL AMOUNTS OF  
10-15MM/DAY AND MAXIMA OF 20-30MM. THE DIGGING MID/UPPER LEVEL  
TROUGH IS TO ALSO ENHANCE CONVECTION ACROSS CUBA AND THE BAHAMAS.  
OVER THE NORTHWEST BAHAMAS EXPECTING RAINFALL AMOUNTS OF  
00-05MM/DAY AND MAXIMA OF 10MM ON FRIDAY. ACROSS JAMAICA EXPECTING  
RAINFALL AMOUNTS OF 00-05MM/DAY AND MAXIMA 10MM. IN RESPONSE TO  
DEEPENING TROUGH ALOFT...THE FOCUS OF THE CONVECTION SHIFTS TO THE  
SOUTHEAST BAHAMAS-EASTERN CUBA ON SATURDAY-SUNDAY. OVER THE  
SOUTHEAST BAHAMAS-EASTERN CUBA EXPECTING RAINFALL AMOUNTS OF  
05-10MM/DAY AND MAXIMA OF 15-25MM. ON SATURDAY MAXIMA OVER EASTERN  
CUBA-JAMAICA INCREASE TO 20-35MM.  
 
THE EASTERN PACIFIC ITCZ MEANDERS EAST ACROSS SOUTHERN CENTRAL  
AMERICA TO NORTHERN SOUTH AMERICA. OVER COSTA RICA-PANAMA TO  
NORTHERN COLOMBIA THIS IS TO FAVOR SCATTERED DEEP CONVECTION WITH  
ACCUMULATION OF 05-10MM/DAY AND MAXIMA OF 15-20MM/DAY. ACROSS  
WESTERN COLOMBIA-NORTHWEST VENEZUELA EXPECTING SIMILAR RAINFALL  
AMOUNTS...WITH ACCUMULATION OF 05-10MM/DAY AND MAXIMA OF 15-20MM  
THROUGH FRIDAY MORNING. ON FRIDAY-SATURDAY...AS A DEEP LAYER  
WESTERLY FLOW ESTABLISHES ACROSS THE EASTERN PACIFIC...THIS WILL  
INCREASES TO 10-15MM/DAY AND MAXIMA OF 20-40MM...WHILE ON SATURDAY  
TO SUNDAY IT IS TO SUSTAIN RAINFALL AMOUNTS OF 15-20MM/DAY AND  
MAXIMA OF 30-60MM. ON SUNDAY THE ONSHORE FLOW WEAKENS...AND AS A  
RESULT IT WILL DECREASE AGAIN TO 05-10MM/DAY AND MAXIMA OF  
15-20MM. OVER CENTRAL-EASTERN VENEZUELA DIURNAL CONVECTION ALONG  
THE NEAR EQUATORIAL TROUGH WILL SUSTAIN RAINFALL AMOUNTS  
05-10MM/DAY AND MAXIMA OF 15-25MM. OVER NORTHEAST VENEZUELA AND  
NORTHERN GUYANA THIS IS TO FAVOR RAINFALL AMOUNTS OF 05-10MM/DAY  
AND MAXIMA OF 15MM. THROUGH SATURDAY THE MAXIMA INCREASES TO  
15-20MM...PEAKING AT 20-35MM ON SUNDAY. PLUME OF MOISTURE IS TO  
THEN LIFT ACROSS TRINIDAD TO THE SOUTHERN WINDWARD ISLES EARLY ON  
FRIDAY MORNING...TO TRIGGER RAINFALL AMOUNTS OF 05-10MM/DAY AND  
MAXIMA OF 15MM. THROUGH SUNDAY THIS INCREASES TO 10-15MM/DAY AND  
MAXIMA OF 20-35MM.  
 
TROPICAL/EASTERLY WAVES INITIALIZED AT 12UTC:  
INITIAL 24 36 48 60 72 84 96 TYPE SOF  
34W 37W 39W 42W 45W 48W 51W 54W TW 12N  
61W 63W 65W 66W 68W 70W 71W 73W TUTT INDCD 24N  
65W 67W 69W 71W 73W 75W 77W 78W TUTT INDCD 21N  
 
69W 71W 73W 75W DISSIPATES TW 17N  
 
A TROPICAL WAVE ALONG 34W AND SOUTH OF 12N REACHES FRENCH GUIANA  
EARLY ON SUNDAY MORNING. HOWEVER...MOST ACTIVE CONVECTION WITH  
THIS FEATURE IS EXPECTED ALONG THE ITCZ TO THE NORTH. ACROSS  
FRENCH GUIANA-SURINAME THIS IS TO TRIGGER RAINFALL AMOUNTS OF  
05-10MM/DAY AND MAXIMA OF 15MM.  
 
A TUTT INDUCED TROUGH ALONG 61W TO 24N IS TO INTERACT WITH THE  
ITCZ TO FAVOR ISOLATED TO SCATTERED CONVECTION ACROSS THE WINDWARD  
ISLANDS-TRINIDAD/TOBAGO-NORTHEAST VENEZUELA. IN THIS AREA  
EXPECTING ACCUMULATION OF 05-10MM/DAY AND MAXIMA OF 15MM THROUGH  
FRIDAY MORNING. PLUME OF MOISTURE IS TO THEN LIFT ACROSS THE  
LEEWARD ISLES LATER ON SATURDAY TO SUSTAIN RAINFALL AMOUNTS OF  
10-15MM/DAY AND MAXIMA OF 20-30MM. THIS SPREADS TO PUERTO  
RICO/DOMINICAN REPUBLIC ON SATURDAY-SUNDAY TO TRIGGER RAINFALL  
AMOUNTS OF 10-15MM/DAY AND MAXIMA OF 20-35MM.  
 
ANOTHER TUTT INDUCED WAVE ALONG 65W TO 21N WILL MEANDER  
WEST-SOUTHWEST ACROSS THE EASTERN CARIBBEAN. OVER THE NEXT TWO  
DAYS THIS IS TO REMAIN ON THE CONVERGENT SIDE OF WANING MID/UPPER  
LEVEL RIDGE ENVELOPING THE CARIBBEAN. AS IT PULLS ACROSS PUERTO  
RICO THIS IS TO ONLY TRIGGER RAINFALL AMOUNTS OF 00-05MM/DAY AND  
MAXIMA OF 10MM THROUGH FRIDAY MORNING. ACROSS HISPANIOLA IT IS TO  
TRIGGER RAINFALL AMOUNTS OF 05-10MM/DAY AND MAXIMA OF 15MM. ACROSS  
THE SOUTHEAST BAHAMAS AND THE TURKS THIS WILL SUSTAIN RAINFALL  
AMOUNTS OF 05-10MM/DAY AND MAXIMA OF 15-25MM.  
 
WANING TROPICAL WAVE ALONG 69W TO 17N IS TO DISSIPATE LATER ON  
FRIDAY. MEANWHILE...ACROSS PANAMA THIS IS TO SUSTAIN RAINFALL  
AMOUNTS OF 05-10MM/DAY AND MAXIMA OF 15-20MM.  
 
GUY...NMS (BELIZE)  
PECK...MS (JAMAICA)  
RIVAS...SENAMHI (PERU)  
DAVISON...WPC (USA)  
 

 
 
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