976  
FXCA20 KWBC 071935  
PMDCA  
 
TROPICAL DISCUSSION - INTERNATIONAL DESKS  
NWS WEATHER PREDICTION CENTER COLLEGE PARK MD  
234 PM EST TUE NOV 07 2017  
 
TROPICAL DISCUSSION FROM NOV 07/12 UTC: WEST OVER THE DOMAIN...A  
BROAD MID/UPPER LEVEL RIDGE EXTENDS ACROSS MEXICO-THE GULF TO THE  
SOUTHERN USA. AT 500/250 HPA THE RIDGE CENTERS ON A CLOSED HIGH  
OVER MEXICO NEAR 20N 102W. CONSISTENT WITH PREVIOUS FORECAST THE  
STRONG MID/UPPER LEVEL RIDGE PATTERN IS TO HOLD THROUGH WEDNESDAY  
MORNING. LATER IN THE DAY...AS A POLAR TROUGH DEEPEN ACROSS  
TEXAS...THE RIDGE IS TO RAPIDLY WEAKEN. MEANWHILE...THE MID LEVEL  
RIDGE PATTERN SUSTAINS A STRONG SUBSIDENCE INVERSION ACROSS MEXICO  
THAT IS TO INHIBIT ORGANIZED DEEP CONVECTION. ALTHOUGH THE RIDGE  
WEAKENS...THE INVERSION IS EXPECTED TO GENERALLY HOLD THROUGH THE  
END OF THE WEEK. AT LOW LEVELS THIS SUSTAINS A CLOSED HIGH OVER  
THE NORTHWEST GULF OF MEXICO. THE LOW LEVEL HIGH PRESSURE RIDGE  
FAVORS A LIGHT NORTHEASTERLY FLOW ACROSS THE GULF OF MEXICO/THE  
YUCATAN TO THE WESTERN CARIBBEAN. OVER VERACRUZ-CHIAPAS IN  
SOUTHERN MEXICO THIS IS TO FAVOR COASTAL CONVECTION WITH  
ACCUMULATION OF 05-10MM/DAY AND MAXIMA OF 15-20MM ON WEDNESDAY.  
OVER NORTHERN CENTRAL AMERICA THIS IS TO CONVERGE ACROSS NORTHERN  
HONDURAS/ISLAS DE LA BAHIA TO SUSTAIN RAINFALL AMOUNTS OF  
05-10MM/DAY AND MAXIMA OF 15-30MM THROUGH WEDNESDAY MORNING. ON  
WEDNESDAY TO THURSDAY IT DECREASES TO 05-10MM/DAY AND MAXIMA OF  
15-20MM.  
 
THE POLAR TROUGH IS TO AMPLIFY ACROSS THE CENTRAL USA ON  
WEDNESDAY. AXIS REACHES MAXIMUM AMPLITUDE ON  
THURSDAY-FRIDAY...WHEN IT IS TO EXTEND ACROSS THE SOUTHEAST USA TO  
THE GULF OF MEXICO. AT LOW LEVELS THE POLAR TROUGH SUSTAINS A  
SURFACE FRONT THAT MOVES ACROSS TEXAS EARLY ON WEDNESDAY...INTO  
THE NORTHEAST STATES OF MEXICO ON WEDNESDAY EVENING. LATER IN THE  
WEEK THE FRONT SURGES ACROSS FLORIDA WHILE TRAILING END REMAINS  
OVER NORTHEAST MEXICO/SOUTH TEXAS. THE SURGING FRONT IS TO THEN  
SUSTAIN A PREFRONTAL SHEAR LINE ACROSS THE BAHAMAS CUBA TO THE  
WESTERN CARIBBEAN-HONDURAS. OVER THE BAHAMAS AND ALONG THE NORTH  
COAST OF CUBA...IN A COOL ADVECTIVE PATTERN...THIS IS TO FAVOR  
SCATTERED SHOWERS ON THURSDAY TO FRIDAY...WITH RAINFALL AMOUNTS OF  
05-10MM/DAY AND MAXIMA OF 15-20MM. ON FRIDAY...OVER THE NORTHERN  
BAHAMAS EXPECTING RAINFALL AMOUNTS OF 00-05MM/DAY AND MAXIMA OF  
10MM...WHILE OVER CENTRAL AND EASTERN CUBA EXPECTING RAINFALL  
AMOUNTS OF 05-10MM AND MAXIMA OF 15-20MM. HIGHER AMOUNTS ARE  
EXPECTED ACROSS NORTHERN HONDURAS ON THURSDAY AND FRIDAY...WHERE  
UNDER INFLUENCE OF THE SHEAR LINE AND BRISK NORTHEASTERLY WINDS  
EXPECTING RAINFALL AMOUNTS OF 15-20MM/DAY AND MAXIMA OF 25-50MM.  
ON FRIDAY THE MAXIMA INCREASES TO 35-70MM.  
 
A TUTT LIES TO THE EAST...WITH AXIS TO THE SOUTH-SOUTHWEST ACROSS  
THE SOUTHEAST BAHAMAS/TURKS AND CAICOS-EASTERN CUBA-JAMAICA TO THE  
CENTRAL CARIBBEAN. THIS SEPARATES THE SUBTROPICAL RIDGE TO THE  
WEST FROM A CELL OF THE SUBEQUATORIAL RIDGE TO THE EAST. THE  
SUBEQUATORIAL RIDGE EXTENDS FROM VENEZUELA TO THE EASTERN  
CARIBBEAN. THE NORTHWEST/CENTRAL BAHAMAS-CUBA-JAMAICA AND THE  
CAYMAN ISLES LIE ON THE CONVERGENT SIDE OF THE UPPER LEVEL TROUGH.  
THE SOUTHEAST BAHAMAS/TURKS AND CAICOS-HISPANIOLA-PUERTO RICO AND  
THE LESSER ANTILLES ARE ON THE DIVERGENT SIDE OF THE UPPER LEVEL  
RIDGE/TROUGH. AS THE RIDGE TO THE WEST WEAKENS ON  
THURSDAY-FRIDAY...AND THE POLAR TROUGH DEEPENS ACROSS THE  
GULF...THE TUTT ALOFT IS TO GRADUALLY FILL WHILE SHEARING SHORT  
WAVE ENERGY TO THE NORTHEAST. AT LOW LEVELS...THE TROUGH ALOFT IS  
INDUCING THE NORTHWARD AMPLIFICATION OF AN INVERTED TROUGH ACROSS  
THE CENTRAL CARIBBEAN. THIS...IN-TURN...SUSTAINS A MOIST  
SOUTHEASTERLY FLOW ACROSS THE EASTERN CARIBBEAN...WITH DEEP  
MOISTURE POOLING ACROSS HISPANIOLA-PUERTO RICO AND THE NORTHEAST  
CARIBBEAN ISLES. IN THIS AREA PWAT CONTENT PEAKS AROUND 50MM. THE  
INVERTED TROUGH EVOLVES INTO A CLOSED LOW OVER THE CENTRAL  
CARIBBEAN EARLY ON WEDNESDAY...FORECAST TO MEANDER TO THE  
SOUTH-SOUTHEAST OF JAMAICA ON THURSDAY-FRIDAY. THIS WILL THEN DRAW  
A PLUME OF MOISTURE ACROSS HAITI TO JAMAICA. OVER THE LEEWARD  
ISLES THIS IS TO FAVOR RAINFALL AMOUNTS OF 05-10MM/DAY AND MAXIMA  
OF 15MM...DECREASING TO 00-05MM/DAY AND MAXIMA OF 10MM ON  
WEDNESDAY AND ONWARD. ACROSS PUERTO RICO AND THE DOMINICAN  
REPUBLIC EXPECTING RAINFALL AMOUNTS OF 10-15MM/DAY AND MAXIMA OF  
20-30MM. OVER PUERTO RICO THIS INCREASES TO 30-60MM ON WEDNESDAY  
UNDER INFLUENCE OF A TROPICAL WAVE. OVER HAITI INITIALLY EXPECTING  
RAINFALL AMOUNTS OF 10-15MM/DAY AND MAXIMA OF 20-30MM. THROUGH  
THURSDAY THIS INCREASES TO 15-20MM/DAY AND MAXIMA OF  
25-50MM...WHILE ON FRIDAY THE MAXIMA PEAKS AT 40-80MM. OVER  
JAMAICA...AS PLUME OF DEEP TROPICAL MOISTURE ADVECTS  
WESTWARD...EXPECTING MODERATE CONVECTION ON THURSDAY AND FRIDAY TO  
FAVOR RAINFALL AMOUNTS OF 10-15MM/DAY AND MAXIMA OF 20-40MM.  
 
FURTHERMORE...THE MID/UPPER LEVEL TROUGH OVER THE CENTRAL  
CARIBBEAN IS TO INTERACT WITH THE ITCZ OVER PANAMA/COSTA RICA AND  
THE NEAR EQUATORIAL TROUGH OVER NORTHERN COLOMBIA. ACROSS  
PANAMA-COSTA RICA EXPECTING RAINFALL AMOUNTS OF 05-10MM/DAY AND  
MAXIMA OF 15-25MM/DAY IN SCATTERED CONVECTION. OVER THE EASTERN  
PACIFIC...DEEPENING TROUGH/LOW OVER THE SOUTHERN CARIBBEAN IS TO  
FAVOR A MOIST WESTERLY FLOW THAT IS TO CONVERGE ON THE WESTERN  
PLAINS/ANDEAN REGION OF COLOMBIA. IN THIS AREA INITIALLY EXPECTING  
RAINFALL AMOUNTS OF 10-15MM/DAY AND MAXIMA OF 20-45MM. THROUGH  
WEDNESDAY THIS INCREASES TO 15-20MM/DAY AND MAXIMA OF 35-70MM. ON  
THURSDAY-FRIDAY...AS THE UPPER TROUGH PULLS TO THE  
NORTHEAST...THIS DECREASES TO 15-20MM/DAY AND MAXIMA OF  
25-50MM...WHILE ON FRIDAY THE MAXIMA IS TO PEAK AT 20-30MM.  
 
THE CELL OF THE SUBEQUATORIAL RIDGE OVER THE EASTERN  
CARIBBEAN/NORTHERN SOUTH AMERICA IS TO VENT NEAR EQUATORIAL TROUGH  
RELATED CONVERGENCE ACROSS VENEZUELA AND ITCZ RELATED CONVECTION  
ACROSS THE GUIANAS. ACROSS VENEZUELA EXPECTING RAINFALL AMOUNTS OF  
05-10MM/DAY AND MAXIMA OF 15-20MM. ON WEDNESDAY TO THURSDAY THIS  
INCREASES TO 10-15MM/DAY AND MAXIMA OF 20-35MM. ACROSS THE GUIANAS  
EXPECTING RAINFALL AMOUNTS OF 10-15MM/DAY AND MAXIMA OF 20-40MM.  
THROUGH THURSDAY THIS DECREASES TO 10-15MM/DAY AND MAXIMA OF  
20-30MM.  
 
TROPICAL/EASTERLY WAVES INITIALIZED AT 12UTC:  
INITIAL 24 36 48 60 72 84 96 TYPE SOF  
59W 60W 62W 65W 67W 69W 71W 73W TW 19N  
73W 74W 74W 75W 75W 76W 77W 78W TUTT INDCD 21N  
85W DISSIPATES EW 17N  
 
TROPICAL WAVE ALONG 59W AND SOUTH OF 19N IS TO INTERACT WITH THE  
ITCZ OVER NORTHERN GUYANA/NORTHEAST VENEZUELA AND THE SOUTHERN  
WINDWARD ISLES TO TRIGGER SCATTERED DEEP CONVECTION WITH  
ACCUMULATION OF 10-15MM/DAY AND MAXIMA OF 20-40MM. ON THE  
FRENCH-LEEWARD ISLES EXPECTING ACCUMULATION OF 05-10MM/DAY AND  
MAXIMA OF 15MM. ACROSS VENEZUELA THIS IS TO INTERACT WITH THE NEAR  
EQUATORIAL TROUGH TO SUSTAIN RAINFALL AMOUNTS OF 10-15MM/DAY AND  
MAXIMA OF 20-35MM ON WEDNESDAY-THURSDAY. OVER PUERTO RICO  
EXPECTING ACCUMULATION OF 15-20MM/DAY AND MAXIMA OF  
30-60MM...WHILE OVER HISPANIOLA THIS WILL SUSTAIN RAINFALL AMOUNTS  
OF 15-20MM/DAY AND MAXIMA OF 25-50MM. ACROSS HAITI THIS INCREASES  
TO MAXIMA OF 40-80MM ON FRIDAY-SATURDAY. OVER EASTERN  
COLOMBIA/NORTHWEST VENEZUELA THIS IS TO THEN FAVOR RAINFALL  
AMOUNTS OF XX-10-15MM/DAY AND MAXIMA OF 20-30MM.  
 
THE TUTT OVER THE CENTRAL CARIBBEAN SUSTAINS THE NORTHWARD  
AMPLIFICATION OF A TROUGH ACROSS THE CENTRAL CARIBBEAN ALONG 73W  
TO 21N. THIS BECOMES BETTER ORGANIZED ON WEDNESDAY-THURSDAY WHILE  
CENTERING ON A CLOSED LOW TO THE SOUTH-SOUTHEAST OF JAMAICA. THIS  
WILL ENHANCE MOISTURE CONVERGENCE ACROSS THE HAITIAN PENINSULA ON  
THURSDAY...TO SUSTAIN RAINFALL AMOUNTS OF 15-20MM/DAY AND MAXIMA  
OF 25-50MM. OVER THE SOUTHEAST BAHAMAS-EASTERN CUBA AND THE TURKS  
AND CAICOS IT WILL SUSTAIN RAINFALL AMOUNTS OF 15-20MM/DAY AND  
MAXIMA OF 30-60MM. ON WEDNESDAY-THURSDAY THIS DECREASES TO  
10-15MM/DAY AND MAXIMA OF 20-35MM. ON THURSDAY-FRIDAY THIS WILL  
SUSTAIN A MOIST PLUME ACROSS JAMAICA...WITH RAINFALL AMOUNTS OF  
10-15MM/DAY AND MAXIMA OF 20-40MM.  
 
GUY...NMS (BELIZE)  
PECK...MS (JAMAICA)  
RIVAS...SENAMHI (PERU)  
DAVISON...WPC (USA)  
 

 
 
CLICK HERE TO GO TO PREVIOUS BULLETINS.

The Nexlab HPC Page Main Text Page