122  
FXCA20 KWBC 091932  
PMDCA  
 
TROPICAL DISCUSSION - INTERNATIONAL DESKS  
NWS WEATHER PREDICTION CENTER COLLEGE PARK MD  
231 PM EST THU NOV 09 2017  
 
TROPICAL DISCUSSION FROM NOV 09/12 UTC: POLAR TROUGH STREAMING  
ACROSS THE USA MOVES TO THE EASTERN USA/GULF OF MEXICO LATER  
TODAY. ON FRIDAY TO SATURDAY IT IS TO THEN MEANDER EAST INTO THE  
WESTERN ATLANTIC WHILE LIFTING OVER A RIDGE TO THE EAST. AT LOW  
LEVELS THE ASSOCIATED FRONT MOVES TO NORTHERN  
FLORIDA-GULF-TAMAULIPAS IN NORTHEAST MEXICO LATER THIS AFTERNOON.  
EARLY ON FRIDAY MORNING IT MOVES TO CENTRAL FLORIDA WHILE ITS  
TRAILING END REMAINS OVER THE NORTHERN GULF-NORTHERN TAMAULIPAS/  
SOUTHERN TEXAS. THE BOUNDARY DRIFTS TO THE NORTHWEST BAHAMAS-SOUTH  
FLORIDA/KEYS ON SATURDAY EVENING...BUT ON SUNDAY IT RETROGRESSES  
TO CENTRAL FLORIDA/SOUTHERN USA. AS IT MOVES ACROSS FLORIDA...THE  
FRONT WILL SUSTAIN A PREFRONTAL SHEAR LINE ACROSS THE NORTHWEST  
BAHAMAS-WESTERN CUBA-GULF OF HONDURAS EARLY ON FRIDAY MORNING.  
LATER IN THE DAY IT MEANDERS TO THE CENTRAL BAHAMAS-CENTRAL CUBA  
TRAILING TO THE WESTERN CARIBBEAN/NORTHERN HONDURAS. LATER ON  
SATURDAY IT RETROGRESSES TO THE NORTHWEST BAHAMAS-WESTERN CUBA TO  
GULF OF HONDURAS/CENTRAL GUATEMALA. THE SHEAR LINE BECOMES ILL  
DEFINED ON SUNDAY MORNING. ACROSS THE BAHAMAS THIS IS TO FAVOR  
RAINFALL AMOUNTS OF 05-10MM/DAY AND MAXIMA OF 15-20MM THROUGH  
FRIDAY MORNING...AND 05-10MM/DAY AND MAXIMA OF 15MM ON FRIDAY TO  
SATURDAY. ACROSS CUBA EXPECTING RAINFALL AMOUNTS OF 05-10MM/DAY  
AND MAXIMA OF 15-20MM/DAY THROUGH SATURDAY. OVER VERACRUZ  
MEXICO...THE FRONT/POLAR RIDGE TO THE WEST WILL SUSTAIN BRISK  
NORTHERLY WIND ACROSS THE GULF OF MEXICO THROUGH FRIDAY. THIS WILL  
ENHANCE COASTAL CONVERGENCE TO FAVOR RAINFALL AMOUNTS OF  
10-15MM/DAY AND MAXIMA OF 20-30MM ON FRIDAY. ACROSS THE CAYMAN  
ISLES THE SHEAR LINE IS TO SUSTAIN RAINFALL AMOUNTS OF 10-15MM/DAY  
AND MAXIMA OF 20-30MM ON FRIDAY TO SATURDAY. HIGHER AMOUNTS WITH  
THE SHEAR LINE ARE EXPECTED ACROSS NORTHERN HONDURAS ON THURSDAY  
AND FRIDAY. ON THURSDAY...UNDER INFLUENCE OF THE PREFRONTAL SHEAR  
LINE AND BRISK NORTHEASTERLY WINDS EXPECTING RAINFALL AMOUNTS OF  
20-30MM/DAY AND MAXIMA OF 40-80MM. ON FRIDAY EXPECTING  
ACCUMULATION OF 15-20MM/DAY AND MAXIMA OF 35-70MM. ON SATURDAY  
MOST ACTIVE IS EXPECTED OVER NORTHWEST HONDURAS-BELIZE AND CENTRAL  
GUATEMALA WITH ACCUMULATION OF 15-20MM/DAY AND MAXIMA OF 25-50MM.  
ON SUNDAY THIS INCREASES AGAIN TO 15-30MM/DAY AND MAXIMA OF  
40-80MM.  
 
SHORT WAVE RIDGE LIES TO THE SOUTH OF THE MID/UPPER LEVEL  
TROUGH...WITH AXIS INITIALLY CONFINING TO THE WESTERN AND NORTHERN  
STATES OF MEXICO. AS THE POLAR TROUGH LIFTS TO THE EAST-NORTHEAST  
DURING THE WEEKEND...THE RIDGE IS TO THEN STRENGTHEN TO ENVELOP  
CENTRAL/NORTHERN MEXICO AND THE SOUTHWEST USA. THE BUILDING RIDGE  
WILL SUSTAINS A MID LEVEL SUBSIDENCE CAP THAT IS TO INHIBIT  
ORGANIZED CONVECTION ACROSS CENTRAL-NORTHERN MEXICO.  
 
FARTHER EAST...A TUTT EXTENDS ACROSS THE CENTRAL CARIBBEAN WHILE  
CENTERING ON A CLOSED LOW OVER JAMAICA. CELL OF THE SUBEQUATORIAL  
RIDGE EXTENDS ACROSS THE EASTERN CARIBBEAN TO NORTHERN SOUTH  
AMERICA. UNDER PRESSURE FROM THE POLAR TROUGH OVER THE GULF...THE  
UPPER LEVEL TUTT IS FORECAST TO RAPIDLY WEAKEN WHILE SHEARING  
SHORT WAVE ENERGY TO THE NORTHEAST ACROSS THE DOMINICAN REPUBLIC.  
AT MID LEVELS...THIS SUSTAINS A SHORT WAVE TROUGH OVER THE CENTRAL  
CARIBBEAN WITH A CLOSED LOW TO THE SOUTH-SOUTHWEST OF JAMAICA. THE  
MID LEVEL CIRCULATION IS TO GRADUALLY WEAKEN DURING THE  
WEEKEND...AND EARLY NEXT WEEK IT IS EXPECTED TO FILL.  
MEANWHILE...IN INTERACTION WITH THE SUBEQUATORIAL RIDGE...AN UPPER  
DIVERGENT PATTERN IS TO PERSIST ACROSS HISPANIOLA-PUERTO RICO AND  
THE VIRGIN ISLES. AT LOW LEVELS THIS REFLECTS AS AN INVERTED  
TROUGH THAT EXTENDS NORTH BETWEEN COLOMBIA AND HAITI...WITH AXIS  
ANCHORING ON A LOW NORTH-NORTHWEST OF BARRANQUILLA IN NORTHERN  
COLOMBIA. THE LOW LEVEL TROUGH IS ENHANCING MOISTURE CONVERGENCE  
ACROSS THE NORTHERN CARIBBEAN...WITH PWAT CONTENT OF 50-70MM. THE  
850 HPA LOW IS TO MEANDER SOUTH OF JAMAICA DURING THE NEXT COUPLE  
OF DAYS...WEAKENING DURING THE WEEKEND. MEANWHILE...ACROSS PUERTO  
RICO AND THE VIRGIN ISLES EXPECTING RAINFALL AMOUNTS OF  
15-20MM/DAY AND MAXIMA OF 25-50MM. THROUGH SUNDAY THIS DECREASES  
TO 05-10MM/DAY AND MAXIMA OF 15-20MM. ACROSS HISPANIOLA EXPECTING  
ACCUMULATION OF 15-20MM/DAY AND MAXIMA OF 25-50MM. ON FRIDAY THIS  
INCREASES TO 15-30MM/DAY AND MAXIMA OF 40-80MM. A LULL IN ACTIVITY  
ON SATURDAY WILL RESULT IN RAINFALL AMOUNTS OF 10-15MM/DAY AND  
MAXIMA OF 20-30MM...BUT ON SUNDAY THE MAXIMA INCREASES TO 25-50MM.  
PLUME OF DEEP TROPICAL MOISTURE IS TO THEN ADVECT ACROSS THE  
CENTRAL CARIBBEAN TO JAMAICA EARLY IN THE CYCLE...TO SUSTAIN  
RAINFALL AMOUNTS OF 10-15MM/DAY AND MAXIMA OF 20-40MM. ON FRIDAY  
THIS INCREASES TO 15-20MM/DAY AND MAXIMA OF 30-60MM. ON SATURDAY  
THIS DECREASES TO 05-10MM/DAY AND MAXIMA OF 15-25MM.  
 
OTHER CONVECTION TO THE SOUTH IS EXPECTED ACROSS PANAMA-COSTA RICA  
IN INTERACTION WITH THE ITCZ...WITH ACCUMULATION OF 10-15MM/DAY  
AND MAXIMA OF 20-35MM. ON FRIDAY THIS DECREASES TO 05-10MM/DAY AND  
MAXIMA OF 15-20MM. THROUGH SUNDAY THE DAILY MAXIMA INCREASES AGAIN  
TO 20-35MM. OVER COLOMBIA...THE LOW OVER THE CENTRAL CARIBBEAN  
FAVORS A LONG FETCH WESTERLY FLOW ACROSS THE EASTERN PACIFIC THAT  
IS CONVERGING ON THE ANDEAN REGION/WESTERN PLAINS. IN THIS AREA  
EXPECTING RAINFALL AMOUNTS OF 15-20MM/DAY AND MAXIMA OF 25-50MM.  
ON SATURDAY...COASTAL CONVERGENCE WILL SUSTAIN RAINFALL AMOUNTS OF  
10-15MM/DAY AND MAXIMA OF 20-40MM...WHILE OVER THE ANDEAN  
REGION/SIERRA NEVADA DE SANTA MARTA TO THE NORTH EXPECTING  
ACCUMULATION OF 05-10MM/DAY AND MAXIMA OF 15-20MM. ACROSS  
VENEZUELA...MEANDERING UPPER LEVEL CELL OF THE SUBEQUATORIAL RIDGE  
IS TO VENT DIURNAL CONVECTION...TO SUSTAIN RAINFALL AMOUNTS OF  
10-15MM/DAY AND MAXIMA OF 20-30MM. ACROSS THE GUIANAS EXPECTING  
RAINFALL AMOUNTS 05-10MM/DAY AND MAXIMA OF 15-20MM...WITH MOST  
ACTIVE ALONG THE COAST.  
 
TROPICAL/EASTERLY WAVES INITIALIZED AT 12UTC:  
INITIAL 24 36 48 60 72 84 96 TYPE  
SOF  
46W 47W 48W 49W 50W 51W 51W 52W TUTT  
INDCD 23N  
56W 59W 62W 65W 68W 70W 72W 74W EW  
19N  
69W 71W 72W 73W 74W 75W 76W DISSIPATES TW  
20N  
75W 76W 77W 78W 79W 81W 83W 84W TUTT  
INDCD 20N  
 
A TUTT INDUCED TROUGH EXTENDS NORTH ALONG 46W TO 23N. THIS  
MEANDERS WEST TO NORTHERN FRENCH GUIANA EARLY ON SATURDAY  
MORNING...WHERE IN INTERACTION WITH THE ITCZ THIS IS TO TRIGGER  
RAINFALL AMOUNTS OF 05-10MM/DAY AND MAXIMA OF 15-20MM.  
 
AN EASTERLY WAVE ALONG 56W AND TO THE SOUTH OF 19N REACHES THE  
ISLAND CHAIN LATER TODAY. OVER NORTHERN GUYANA/NORTHEAST VENEZUELA  
THIS IS TO FAVOR RAINFALL AMOUNTS OF 05-10MM/DAY AND MAXIMA OF  
15-20MM. OVER THE WINDWARD ISLANDS EXPECTING WIDELY ISOLATED  
CONVECTION WITH LIGHT RAINFALL AMOUNTS...WHILE OVER THE LEEWARD  
ISLES IT IS TO SUSTAIN RAINFALL AMOUNTS OF 00-05MM/DAY AND MAXIMA  
OF 10MM. ACROSS PUERTO RICO-VIRGIN ISLES THIS IS TO FAVOR RAINFALL  
AMOUNTS OF 10-15MM/DAY AND MAXIMA OF 20-40MM ON FRIDAY TO SATURDAY  
MORNING. ACROSS THE DOMINICAN REPUBLIC THIS IS TO THEN TRIGGER  
RAINFALL AMOUNTS OF 10-15MM/DAY AND MAXIMA OF 20-30MM. ACROSS  
HAITI THIS INCREASES TO 15-20MM/DAY AND MAXIMA OF 25-50MM ON  
SUNDAY.  
 
TROPICAL WAVE ALONG 69W TO 20N IS EXPECTED TO GRADUALLY WEAKEN  
WHILE PHASING WITH A TUTT INDUCED TROUGH TO THE WEST.  
MEANWHILE...ACROSS NORTHERN COLOMBIA THIS IS TO TRIGGER RAINFALL  
AMOUNTS OF 15-20MM/DAY AND MAXIMA OF 25-50MM. ACROSS HISPANIOLA  
THIS IS TO SUSTAIN RAINFALL AMOUNTS OF 15-20MM/DAY AND MAXIMA OF  
25-50MM THROUGH FRIDAY MORNING...INCREASING TO 15-30MM/DAY AND  
MAXIMA OF 40-80MM ON FRIDAY TO SATURDAY.  
 
THE TUTT OVER THE CENTRAL CARIBBEAN SUSTAINS A PERTURBATION IN THE  
EASTERLY TRADES WITH AXIS NORTH ALONG 75W TO 20N. AS IT MEANDERS  
OVER THE CENTRAL CARIBBEAN THIS WILL SUSTAIN ORGANIZED CONVECTION  
ACROSS HISPANIOLA WITH ACCUMULATION OF 10-15MM/DAY AND MAXIMA OF  
20-45MM. OVER THE SOUTHEAST BAHAMAS AND THE TURKS THIS IS TO  
TRIGGER RAINFALL AMOUNTS OF 10-15MM/DAY AND MAXIMA OF 20-35MM.  
ACROSS JAMAICA THIS IS TO FAVOR RAINFALL AMOUNTS OF 10-15MM/DAY  
AND MAXIMA OF 20-40MM THROUGH FRIDAY MORNING. ON FRIDAY-SATURDAY  
MAXIMA INCREASES TO 30-60MM.  
 
GUY...NMS (BELIZE)  
PECK...MS (JAMAICA)  
RIVAS...SENAMHI (PERU)  
DAVISON...WPC (USA)  
 

 
 
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