345  
FXCA20 KWBC 021917  
PMDCA  
 
TROPICAL DISCUSSION - INTERNATIONAL DESKS  
NWS WEATHER PREDICTION CENTER COLLEGE PARK MD  
216 PM EST TUE JAN 02 2018  
 
TROPICAL DISCUSSION FROM JAN 02/12 UTC: AT 500 HPA...A BROAD POLAR  
TROUGH EXTENDS OVER NORTH AMERICA-WESTERN ATLANTIC TO THE GULF OF  
MEXICO...WITH AXIS FORECAST TO PERSIST THROUGH THE END OF THE  
WEEK. AS IT HOLDS...SHORT WAVE PERTURBATIONS ARE TO ROUND THE BASE  
OF THE LONG WAVE AXIS FROM TIME TO TIME...WITH A STRONG  
PERTURBATION TO MOVE ACROSS THE NORTHERN GULF EARLY ON WEDNESDAY  
MORNING...REACHING THE FLORIDA PENINSULA/WESTERN CUBA LATER ON  
WEDNESDAY. THIS IS TO THEN QUICKLY LIFT ACROSS THE WESTERN  
ATLANTIC. AT LOW LEVELS...THE DEEP TROUGH SUSTAINS A FRONT ACROSS  
THE NORTHWEST BAHAMAS-STRAITS OF FLORIDA/WESTERN CUBA TO THE  
SOUTHERN STATES OF MEXICO. UNDER INFLUENCE OF THE SHORT WAVE  
TROUGH ROUNDING THE BASE OF THE LONG WAVE AXIS A RAPIDLY TO  
INTENSIFY LOW FORMS OVER THE NORTHWEST BAHAMAS DURING THE EARLY  
MORNING HOURS ON WEDNESDAY...WITH CYCLONE TO RAPIDLY DEEPEN AS IT  
SLOWLY LIFTS TO THE NORTH-NORTHEAST. AS THE GRADIENT TIGHTENS A  
NORTHERLY SURGE OF 30-35KT IS FORECAST ACROSS THE WESTERN GULF OF  
MEXICO ON WEDNESDAY. THIS DRIVES THE FRONT SOUTH ACROSS CUBA TO  
THE WESTERN CARIBBEAN AND ACROSS BELIZE/GUATEMALA TO SOUTHERN  
MEXICO...WHILE SUPPORTING A TEHUANTEPECER JET OF 50KT. THROUGH  
THURSDAY MORNING THE FRONT MOVES ACROSS THE TURKS AND  
CAICOS-EASTERN CUBA-JAMAICA TO NORTHERN HONDURAS...WHILE TRAILING  
ACROSS BELIZE TO SOUTHERN MEXICO. ACROSS THE WESTERN-CENTRAL  
CARIBBEAN THIS IS TO THEN FAVOR BOUNDARY LAYER WINDS OF 25-35KT.  
LATER ON THURSDAY THE FRONT MOVES TO HAITI WHILE TRAILING ACROSS  
THE CENTRAL CARIBBEAN TO NORTHERN HONDURAS-SOUTHERN MEXICO. THE  
FRONTAL BOUNDARY IS TO THEN MEANDER EAST ACROSS THE DOMINICAN  
REPUBLIC SIDE OF HISPANIOLA ON FRIDAY MORNING...WHILE TRAILING  
ACROSS NORTHERN HONDURAS-BELIZE TO SOUTHERN MEXICO. BOUNDARY LAYER  
WINDS OF 25-35KT ARE TO PERSIST OVER THE SOUTHERN CARIBBEAN.  
FURTHERMORE...AS THE NORTHERLIES SURGE ACROSS THE CARIBBEAN  
BASIN...IT IS TO SUSTAIN A PREFRONTAL SHEAR LINE ACROSS EASTERN  
CUBA-JAMAICA TO BOCAS DEL TORO IN WESTERN PANAMA BETWEEN MIDDAY ON  
WEDNESDAY AND EARLY MORNING HOURS ON THURSDAY. THROUGH THURSDAY  
EVENING THE SHEAR LINE IS TO MEANDER ACROSS HAITI WHILE TRAILING  
TO WESTERN PANAMA.  
 
OVER THE NORTHWEST BAHAMAS EXPECTING RAINFALL AMOUNTS OF  
20-30MM/DAY AND MAXIMA OF 50-100MM EARLY IN THE CYCLE. LATER ON  
WEDNESDAY-THURSDAY THIS DECREASES TO 05-10MM/DAY AND MAXIMA OF  
15-25MM. ACROSS WESTERN-CENTRAL CUBA THE FRONT IS TO INITIALLY  
FAVOR RAINFALL AMOUNTS OF 20-30MM/DAY AND MAXIMA OF 40-80MM. ON  
WEDNESDAY EXPECTING ACCUMULATION OF 10-15MM/DAY AND MAXIMA OF  
20-45MM IN POSTFRONTAL CONVECTION. OVER VERACRUZ-CHIAPAS IN  
SOUTHERN MEXICO EXPECTING RAINFALL AMOUNTS OF 15-20MM/DAY AND  
MAXIMA OF 35-70MM ON TUESDAY AND WEDNESDAY...WHILE ON THURSDAY  
EXPECTING RAINFALL AMOUNTS OF 10-15MM/DAY AND MAXIMA OF 20-35MM.  
ACROSS NORTHERN HONDURAS THE SURGING NORTHERLY WINDS ARE TO FAVOR  
RAINFALL AMOUNTS OF 15-20MM/DAY AND MAXIMA OF 30-60MM. THROUGH  
WEDNESDAY EVENING THE MAXIMA INCREASES TO 35-70MM...WHILE ON  
THURSDAY IT DECREASES TO 10-15MM/DAY AND MAXIMA OF 20-45MM. OVER  
THE SOUTHEAST BAHAMAS/TURKS AND CAICOS-JAMAICA THE FRONT IS TO  
TRIGGER RAINFALL AMOUNTS OF 15-30MM/DAY AND MAXIMA OF 40-80MM. AS  
IT ENTERS HAITI EARLY ON THURSDAY...THE FRONT IS TO INITIALLY  
FAVOR RAINFALL AMOUNTS 20-30MM/DAY AND MAXIMA OF 40-80MM. ON  
THURSDAY TO FRIDAY THIS INCREASES TO 35-70MM/DAY AND MAXIMA OF  
100-150MM. HEAVY RAINS WILL SPREAD ACROSS NORTHERN PORTIONS OF THE  
DOMINICAN REPUBLIC EARLY ON FRIDAY MORNING. HIGHER AMOUNTS ARE  
EXPECTED TO THE SOUTH ALONG THE SHEAR LINE. OVER COSTA RICA  
EXPECTING RAINFALL AMOUNTS OF 50-100MM/DAY AND MAXIMA OF 150-200MM  
ON WEDNESDAY TO THURSDAY. ON THURSDAY TO FRIDAY THIS DECREASES TO  
10-15MM/DAY AND MAXIMA OF 20-35MM. ACROSS WESTERN PANAMA EXPECTING  
RAINFALL AMOUNTS OF 50-100MM/DAY AND MAXIMA OF 150-200MM ON  
WEDNESDAY TO THURSDAY...WHILE ON THURSDAY TO FRIDAY EXPECTING  
RAINFALL AMOUNTS OF 75-125MM/DAY AND MAXIMA OF 200-300MM.  
 
AS THE POLAR TROUGH DEEPENS TO THE NORTH...IT IS TO FAVOR THE  
NORTHWARD AMPLIFICATION OF THE PANAMANIAN LOW/TROUGH ACROSS  
EASTERN PANAMA-GULF OF URABA TO THE SOUTHERN CARIBBEAN. IN THIS  
AREA THE FLOW ORGANIZED INTO A CLOSED CYCLONIC CIRCULATION...A  
FEATURE THAT PERSISTS OVER THE NEXT COUPLE OF DAYS. AS IT MEANDERS  
OVER THE SOUTHERN CARIBBEAN THIS WILL ENHANCE LOW LEVEL MOISTURE  
CONVERGENCE ACROSS COSTA RICA-PANAMA AND ISLA DE SAN ANDRES TO  
SUSTAIN RAINFALL AMOUNTS OF 15-20MM/DAY AND MAXIMA OF 30-60MM.  
OTHER CONVECTION IS EXPECTED ACROSS WESTERN COLOMBIA/ANDEAN  
REGION-THE DARIEN IN EASTERN PANAMA TO NORTHWEST VENEZUELA. IN  
THIS AREA EXPECTING RAINFALL AMOUNTS OF 05-10MM/DAY AND MAXIMA OF  
15-25MM.  
 
A RIDGE LIES TO THE EAST OF THE CONTINENTAL TROUGH...ANCHORING AT  
500 HPA ON A CLOSED HIGH OVER THE WESTERN ATLANTIC. THE HIGH  
EXTENDS A RIDGE TO THE SOUTHWEST ACROSS THE ISLAND CHAIN TO THE  
EASTERN CARIBBEAN/NORTHERN VENEZUELA. THIS IS TO GENERALLY PERSIST  
OVER THE NEXT 48-60 HRS...WITH SOME EROSION POSSIBLE DURING THE  
DAY ON THURSDAY. MEANWHILE...THE PERSISTENT RIDGE WILL SUSTAIN A  
FAIRLY STRONG CAP INVERSION ACROSS THE NORTHEAST CARIBBEAN THAT IS  
TO INHIBIT ORGANIZED DEEP CONVECTION. AT LOW LEVELS...AS THE POLAR  
TROUGH DEEPENS TO THE WEST...THE LOW-MID LEVEL WINDS OVER THE  
EASTERN CARIBBEAN ARE TO VEER TO THE SOUTHEAST.  
THIS...IN-TURN...WILL SUSTAIN A MOIST ADVECTIVE PATTERN ACROSS THE  
WINDWARD ISLES TO THE EASTERN CARIBBEAN. MOISTURE IS TO THEN  
CONVERGE ACROSS PUERTO RICO-VIRGIN ISLES LATER IN THE CYCLE.  
CONVECTION FARTHER TO THE SOUTH IS EXPECTED ACROSS NORTHERN  
GUYANA-NORTHEAST VENEZUELA...WITH ACCUMULATION OF 05-10MM/DAY AND  
MAXIMA OF 15-20MM. THIS DECREASES THROUGH THURSDAY WITH  
ACCUMULATION OF 05-10MM/DAY AND MAXIMA OF 15MM. OVER NORTHERN  
FRENCH GUIANA...MEANWHILE...EXPECTING RAINFALL AMOUNTS OF  
05-10MM/DAY AND MAXIMA OF 15MM.  
 
TROPICAL/EASTERLY WAVES INITIALIZED AT 12UTC:  
INITIAL 24 36 48 60 72 84 96 TYPE SOF  
58W 60W 62W 65W DISSIPATES TUTT INDCD 23N  
 
REMNANTS OF A TUTT INDUCED PERTURBATION IS INITIALIZED EAST OF THE  
ISLAND CHAIN. THIS MOVES ACROSS THE LEEWARD ISLES LATER THIS  
EVENING TO FAVOR RAINFALL AMOUNTS OF 00-05MM/DAY AND MAXIMA OF  
10MM. AS IT ENTERS PUERTO RICO LATER ON WEDNESDAY THE WAVE IS TO  
WEAKEN...TO TRIGGER RAINFALL AMOUNTS OF 00-05MM.  
 
GORDON...NMS (BELIZE)  
PECK...MS (JAMAICA)  
DAVISON...WPC (USA)  
 

 
 
CLICK HERE TO GO TO PREVIOUS BULLETINS.

The Nexlab HPC Page Main Text Page