617  
FXCA20 KWBC 131933  
PMDCA  
 
TROPICAL DISCUSSION - INTERNATIONAL DESKS  
NWS WEATHER PREDICTION CENTER COLLEGE PARK MD  
232 PM EST MON NOV 13 2017  
 
TROPICAL DISCUSSION FROM NOV 09/12 UTC: A MID/UPPER LEVEL HIGH  
OVER SOUTHERN BAJA PENINSULA EXTENDS A RIDGE ACROSS THE  
NORTHERN/CENTRAL STATES OF MEXICO INTO THE SOUTHWEST USA. THE  
UPPER LEVEL RIDGE IS EXPECTED TO HOLD NEARLY UNCHANGED DURING THE  
NEXT FEW DAYS. MEANWHILE...THIS IS TO FAVOR A STRONG CAP INVERSION  
ACROSS MOST OF MEXICO THAT THIS TO INHIBIT ORGANIZED DEEP  
CONVECTION.  
 
SHORT WAVE TROUGH TO THE EAST EXTENDS AT 500 HPA FROM WESTERN CUBA  
TO THE NORTHWEST CARIBBEAN. AT LOW LEVELS THIS SUSTAINS AN INDUCED  
TROUGH OVER THE CENTRAL CARIBBEAN...WITH AXIS NORTH ALONG 82W/83W  
TO 22N. THIS COMBINES WITH A POLAR RIDGE OVER THE SOUTHERN USA IN  
SUPPORT OF A BRISK NORTH-NORTHEASTERLY FLOW ACROSS THE GULF OF  
MEXICO-WESTERN CARIBBEAN. OVER OAXACA IN SOUTHERN MEXICO THIS  
FAVORS A TEHUANTEPECER JET OF 30-40KT. THE FLOW IS CONVERGING  
ACROSS SOUTHERN VERACRUZ WHERE WE EXPECT RAINFALL AMOUNTS OF  
15-20MM/DAY AND MAXIMA OF 25-50MM THROUGH TUESDAY MORNING. THROUGH  
WEDNESDAY THIS DECREASES TO 00-05MM/DAY AND MAXIMA OF 10MM. OVER  
THE WESTERN CARIBBEAN THIS IS ENHANCING LOW LEVEL MOISTURE  
CONVERGENCE ACROSS NORTHERN PORTIONS OF HONDURAS...TO FAVOR  
RAINFALL AMOUNTS OF 35-70MM/DAY AND MAXIMA OF 75-150MM/DAY THROUGH  
WEDNESDAY. ON WEDNESDAY TO THURSDAY THIS IS TO THEN FAVOR RAINFALL  
AMOUNTS OF 10-15MM/DAY AND MAXIMA OF 20-45MM. ACROSS BELIZE TO  
CENTRAL GUATEMALA THIS IS TO FAVOR RAINFALL AMOUNTS OF 05-10MM/DAY  
AND MAXIMA OF 15-20MM. THROUGH WEDNESDAY THIS INCREASES TO  
10-15MM/DAY AND MAXIMA OF 20-40MM. OVER THE CENTRAL  
CARIBBEAN...THE TROUGH IS DRAWING DEEP ITCZ RELATED MOISTURE NORTH  
TO JAMAICA-EASTERN CUBA AND PORTIONS OF HISPANIOLA. ACROSS JAMAICA  
THIS IS TO FAVOR RAINFALL AMOUNTS OF 05-10MM/DAY AND MAXIMA OF  
15-20MM. HIGHER AMOUNTS ARE EXPECTED OVER THE TURKS/SOUTHEAST  
BAHAMAS-EASTERN CUBA...WITH ACCUMULATION OF 15-20MM/DAY AND MAXIMA  
OF 25-50MM..WHILE OVER HISPANIOLA EXPECTING RAINFALL AMOUNTS OF  
00-05MM/DAY AND MAXIMA OF 10MM.  
 
PERSISTENT RIDGE OVER MEXICO/SOUTHWEST USA IS TO STEER SUCCESSIVE  
MID LEVEL TROUGHS ACROSS THE EASTERN USA TO THE WESTERN ATLANTIC.  
THROUGH THE MIDDLE OF THE WEEK THESE ARE TO THEN COMBINE INTO A  
BROAD TROUGH ACROSS THE BAHAMAS-CUBA/HISPANIOLA TO THE NORTHERN  
CARIBBEAN. AS THE TROUGH DEEPENS IT IS TO SIMULTANEOUSLY INTERACT  
WITH MEANDERING MID LEVEL TROUGH OVER THE WESTERN CARIBBEAN. THIS  
WILL DRAW THE LATTER EASTWARD ACROSS THE CENTRAL CARIBBEAN...WHERE  
IT IS TO THEN RAPIDLY SHEAR. THE WEAKENING TROUGH WILL THEN SEND A  
SERIES OF SHORT WAVE PERTURBATIONS ACROSS HISPANIOLA AND PUERTO  
RICO. THIS IS TO THEN PROVIDE DYNAMICAL SUPPORT TO ORGANIZED DEEP  
CONVECTION BY THE MIDDLE OF THE WEEK. AT LOW LEVELS A FRONT IS TO  
MOVE ACROSS FLORIDA BY MIDDAY ON TUESDAY...REACHING THE NORTHWEST  
BAHAMAS LATER IN THE AFTERNOON. DURING THE DAY ON WEDNESDAY THIS  
IS TO MEANDER ACROSS THE CENTRAL BAHAMAS-WESTERN CUBA...WHERE IT  
IS FORECAST TO GRADUALLY WEAKEN/DISSIPATE. AS THE FRONT MOVES TO  
THE NORTHWEST BAHAMAS ON TUESDAY IT IS TO FAVOR RAINFALL AMOUNTS  
OF 05-10MM/DAY AND MAXIMA OF 15MM. THE FRONT/FRONTAL TROUGH NORTH  
OF THE ISLANDS AND DEEPENING MID LEVEL TROUGH WILL THEN INTERACT  
WITH AFOREMENTIONED LOW LEVEL TROUGH MEANDERING OVER THE CENTRAL  
CARIBBEAN. THIS WILL SUSTAIN THE INTENSIFICATION OF THE LOW LEVEL  
FEATURE...WITH A LOW TO FORM SOUTH OF JAMAICA EARLY ON TUESDAY.  
THIS IS TO REMAIN NEARLY STATIONARY THROUGH WEDNESDAY  
MORNING...LIFTING NORTH ACROSS EASTERN JAMAICA LATER IN THE DAY.  
ALSO AT LOW LEVELS...A RIDGE OVER THE CENTRAL CARIBBEAN FAVORS AN  
EASTERLY FLOW ACROSS THE EASTERN CARIBBEAN. AS THE TROUGH DEEPENS  
TO THE WEST THE WINDS ARE TO VEER TO THE SOUTH ON  
TUESDAY...SHIFTING TO THE SOUTH-SOUTHWEST ON WEDNESDAY. PLUME OF  
DEEP TROPICAL MOISTURE IS TO THEN LIFT ACROSS THE CENTRAL  
CARIBBEAN TO PUERTO RICO AND EASTERN PORTIONS OF HISPANIOLA BY  
MIDDAY ON WEDNESDAY-THURSDAY MORNING. PWAT CONTENT IN THIS AREA  
INCREASES FROM 20-35MM EARLY IN THE CYCLE TO 50MM BY THE END OF  
DAY ON WEDNESDAY. UNDER INFLUENCE OF AN ATMOSPHERIC KELVIN  
WAVE...ENVIRONMENTAL CONDITIONS ARE LIKELY TO BECOME FAVORABLE FOR  
AN MCS TO FORM OVER THE NORTHERN CARIBBEAN LATER ON  
WEDNESDAY/THURSDAY MORNING. MOST ACTIVE CONVECTION IS EXPECTED TO  
CLUSTER BETWEEN THE HAITIAN PENINSULA/POUR AU PRINCE AREA AND THE  
PENINSULA DE BARAHONA IN THE DOMINICAN REPUBLIC. IN THIS AREA  
EXPECTING RAINFALL AMOUNTS OF 35-70MM/DAY AND MAXIMA OF 125-150MM.  
ACROSS PUERTO RICO INITIALLY EXPECTING RAINFALL AMOUNTS OF  
00-05MM/DAY AND MAXIMA OF 10MM IN ISOLATED CONVECTION...WITH MOST  
ACTIVE TO INITIALLY CLUSTER OVER NORTHWEST PORTIONS OF THE ISLAND.  
THROUGH WEDNESDAY...AS THE WINDS VEER TO THE  
SOUTH-SOUTHWEST...FOCUS OF THE CONVECTION WILL SHIFT TO NORTHEAST  
PUERTO RICO/SAN JUAN METRO AREA...WITH RAINFALL AMOUNTS INCREASING  
TO 10-15MM/DAY AND MAXIMA OF 20-30MM.  
 
THE MEANDERING LOW LEVEL TROUGH AND ASSOCIATED CLOSED LOW OVER THE  
CENTRAL CARIBBEAN ARE TO INTERACT WITH THE ITCZ OVER SOUTHERN  
CENTRAL AMERICA AND THE NEAR EQUATORIAL TROUGH OVER  
COLOMBIA-VENEZUELA. ACROSS COSTA RICA TO WESTERN PANAMA INITIALLY  
THIS IS TO FAVOR RAINFALL AMOUNTS OF 05-10MM/DAY AND MAXIMA OF  
15-20MM. ON TUESDAY THIS INCREASES TO 20-30MM/DAY AND MAXIMA OF  
50-100MM. ON WEDNESDAY THIS DECREASES TO 15-20MM/DAY AND MAXIMA OF  
25-50MM. ON THE ANDEAN REGION/WEST COAST OF COLOMBIA EXPECTING  
RAINFALL AMOUNTS OF 20-30MM/DAY AND MAXIMA OF 50-100MM/DAY THROUGH  
WEDNESDAY MORNING...DECREASING TO 10-15MM/DAY AND MAXIMA OF  
20-40MM ON WEDNESDAY TO THURSDAY. AS THE DEEPENING LOW DRAWS THE  
ITCZ NORTH INTO THE CARIBBEAN...DIURNAL CONVECTION ACROSS  
SOUTHERN-WESTERN VENEZUELA IS TO SUSTAIN RAINFALL AMOUNTS OF  
15-20MM/DAY AND MAXIMA OF 25-50MM. ON TUESDAY TO WEDNESDAY THIS  
DECREASES TO 05-10MM/DAY AND MAXIMA OF 15-25MM. ACROSS THE GUIANAS  
EXPECTING RAINFALL AMOUNTS OF 00-05MM/DAY AND MAXIMA OF 10MM.  
 
TROPICAL/EASTERLY WAVES INITIALIZED AT 12UTC:  
INITIAL 24 36 48 60 72 84 96 TYPE SOF  
48W 51W 54W 57W 59W 61W 64W 66W EW 16N  
57W 59W 61W 63W 65W 66W 68W 69W EW 13N  
 
AN EASTERLY WAVE ALONG 48W AND SOUTH OF 16N REACHES FRENCH GUIANA  
LATER THIS EVENING...WHERE IT IS TO FAVOR RAINFALL AMOUNTS OF  
00-05MM. ACROSS SURINAME TO GUYANA THIS IS TO THEN FAVOR RAINFALL  
AMOUNTS OF 05-10MM/DAY AND MAXIMA OF 15MM ON TUESDAY TO WEDNESDAY  
MORNING. OVER THE SOUTHERN WINDWARD ISLANDS/TRINIDAD-NORTHEAST  
VENEZUELA IT IS TO SUSTAIN RAINFALL AMOUNTS OF 00-05MM/DAY AND  
MAXIMA OF 10MM ON WEDNESDAY.  
 
AN EASTERLY WAVE ALONG 57W AND SOUTH OF 13N MOVES ACROSS TRINIDAD  
AND THE SOUTHERN WINDWARDS TO NORTHERN GUYANA/EASTERN VENEZUELA  
LATER TODAY...WHERE IT IS TO FAVOR RAINFALL AMOUNTS OF 00-05MM/DAY  
AND MAXIMA OF 10MM. ACROSS VENEZUELA THIS IS TO THEN FAVOR WIDELY  
ISOLATED CONVECTION ON TUESDAY...WHILE ON WEDNESDAY ACTIVITY IS TO  
CLUSTER ACROSS AMAZONIA TO THE SOUTH AND INTO EASTERN COLOMBIA  
WITH RAINFALL AMOUNTS OF 05-10MM/DAY AND MAXIMA OF 15-25MM.  
 
GUY...NMS (BELIZE)  
PECK...MS (JAMAICA)  
RIVAS...SENAMHI (PERU)  
DAVISON...WPC (USA)  
 

 
 
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