597  
FXCA20 KWBC 031923  
PMDCA  
 
TROPICAL DISCUSSION - INTERNATIONAL DESKS  
NWS WEATHER PREDICTION CENTER COLLEGE PARK MD  
223 PM EST WED JAN 03 2018  
 
TROPICAL DISCUSSION FROM JAN 03/12 UTC: A HIGH AMPLITUDE LONG WAVE  
TROUGH IS TO EXTEND AT 500 HPA ACROSS THE EASTERN USA-GULF OF  
MEXICO TO THE YUCATAN/WESTERN CARIBBEAN LATER TODAY. AS IT  
MEANDERS OVER THE EASTERN USA A SHORT WAVE TROUGH QUICKLY MOVES  
ACROSS THE FLORIDA PENINSULA LATER TODAY. THIS VORTEX IS TO  
SUSTAIN A LOW LEVEL CYCLONE THAT IS TO EXPLOSIVELY INTENSIFY  
DURING THE NEXT 24-30 HRS. AT 250 HPA A JET MAXIMA ROUNDS THE BASE  
OF THE TROUGH EARLY IN THE CYCLE. AS IT LIFTS ACROSS THE WESTERN  
ATLANTIC THE JET IS TO INTENSIFY...DRAWING THE TROUGH EAST WHILE  
GRADUALLY PULLING OVER A RIDGE TO THE EAST DURING THE WEEKEND. AT  
LOW LEVELS...A FRONT EXTENDS ACROSS THE NORTHWEST BAHAMAS-SOUTH  
FLORIDA TO SOUTHERN MEXICO. DEEPENING LOW OVER THE NORTHWEST  
BAHAMAS WILL THEN DRIVE THIS BOUNDARY ACROSS THE BASIN WHILE  
SUSTAINING A LOW LEVEL JET OF 30-35KT ACROSS THE GULF OF MEXICO  
EARLY IN THE PERIOD...AND A TEHUANTEPECER JET OF 45-50KT. STRONG  
NORTHERLY WINDS ARE TO THEN ENVELOP THE WESTERN/CENTRAL CARIBBEAN  
DURING THE NEXT FEW DAY. THE STRONG WINDS WILL DISPLACE THE FRONT  
TO WESTERN CUBA...THE YUCATAN AND ALONG THE GULF COAST OF MEXICO  
LATER THIS EVENING. EARLY ON THURSDAY MORNING THE FRONT MOVES TO  
THE SOUTHEAST BAHAMAS/TURKS AND CAICOS-EASTERN  
CUBA-JAMAICA-HONDURAS WHILE TRAILING ACROSS BELIZE/GUATEMALA TO  
SOUTHERN MEXICO. LATER ON THURSDAY THE FRONT MOVES TO  
HAITI-JAMAICA WHILE TRAILING TO NORTHERN HONDURAS-BELIZE-GUATEMALA  
TO THE GULF COAST OF MEXICO. THE FRONT IS TO THEN MEANDER ACROSS  
HISPANIOLA WHILE TRAILING OVER NORTHERN CENTRAL AMERICA-MEXICO  
THROUGH FRIDAY EVENING. ON SATURDAY MORNING THE FRONT RETROGRESSES  
TO EASTERN CUBA-JAMAICA WHILE TRAILING END REMAINS OVER NORTHERN  
HONDURAS-GUATEMALA-MEXICO. ALTHOUGH THE FRONT STARTS TO RETROGRESS  
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 LATER  
TODAY. THIS MEANDERS OVER HISPANIOLA EARLY ON THURSDAY WHILE  
TRAILING ACROSS THE CENTRAL CARIBBEAN TO WESTERN PANAMA. THE SHEAR  
LINE IS TO THEN REMAIN NEARLY STATIONARY THROUGH FRIDAY  
EVENING...MEANDERING TO THE TURKS-EASTERN CUBA/JAMAICA-EASTERN  
NICARAGUA ON SATURDAY.  
 
OVER THE NORTHWEST BAHAMAS THE DEEPENING LOW WILL SUSTAIN RAINFALL  
AMOUNTS OF 10-15MM/DAY AND MAXIMA OF 20-30MM EARLY IN THE  
CYCLE...WHILE ACROSS THE SOUTHEAST BAHAMAS-TURKS AND CAICOS  
EXPECTING RAINFALL AMOUNTS OF 10-15MM/DAY AND MAXIMA OF 20-35MM ON  
THURSDAY-FRIDAY. ACROSS WESTERN-CENTRAL CUBA THE FRONT IS TO  
SUSTAIN RAINFALL AMOUNTS OF 05-10MM/DAY AND MAXIMA OF 15-25MM  
THROUGH THURSDAY MORNING...WHILE OVER FAR EASTERN CUBA EXPECTING  
RAINFALL AMOUNTS OF 10-15MM/DAY AND MAXIMA OF 20-35MM ON THURSDAY  
TO FRIDAY. ACROSS THE CAYMAN ISLANDS EXPECTING ACCUMULATION OF  
05-10MM/DAY AND MAXIMA OF 15-25MM EARLY IN THE PERIOD. ACROSS  
JAMAICA INITIALLY EXPECTING RAINFALL AMOUNTS OF 20-30MM/DAY AND  
MAXIMA OF 40-80MM ON THURSDAY. ON FRIDAY IT DECREASES TO  
15-20MM/DAY AND MAXIMA OF 30-60MM. AS THE FRONT MOVES OVER  
HAITI/NORTHWEST DOMINICAN REPUBLIC ON THURSDAY EXPECTING RAINFALL  
AMOUNTS OF 35-70MM/DAY AND MAXIMA OF 100-150MM...WHILE ON FRIDAY  
TO SATURDAY EXPECTING RAINFALL AMOUNTS OF 15-20MM/DAY AND MAXIMA  
OF 30-60MM. OVER VERACRUZ-NORTHERN CHIAPAS THE FRONTAL NORTHERLIES  
ARE TO TRIGGER RAINFALL AMOUNTS OF 15-20MM/DAY AND MAXIMA OF  
35-70MM THROUGH THURSDAY MORNING...WHILE ON THURSDAY TO FRIDAY  
EXPECTING RAINFALL AMOUNTS OF 10-15MM/DAY AND MAXIMA OF 20-35MM.  
ACROSS SOUTHERN BELIZE-CENTRAL GUATEMALA THE FRONT/NORTHERLIES  
WILL SUSTAIN RAINFALL AMOUNTS OF 05-10MM/DAY AND MAXIMA OF  
15-20MM. ON FRIDAY THIS INCREASES TO 10-15MM/DAY AND MAXIMA OF  
20-30MM. OVER NORTHERN HONDURAS EXPECTING ACCUMULATION OF  
15-20MM/DAY AND MAXIMA OF 35-70MM THROUGH THURSDAY...DECREASING TO  
MAXIMA OF 25-50MM ON THURSDAY TO FRIDAY...WHILE ON FRIDAY TO  
SATURDAY EXPECTING RAINFALL AMOUNTS OF 10-15MM/DAY AND MAXIMA FO  
20-30MM.  
 
HIGHER AMOUNTS ARE EXPECTED TO THE SOUTH AS THE PREFRONTAL SHEAR  
LINE AND A LOW LEVEL JET MEANDER BETWEEN COSTA RICA AND PANAMA.  
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. ON  
SATURDAY...AS THE SHEAR LINE RETROGRESSES...EXPECTING RAINFALL  
AMOUNTS OF 50-100MM/DAY AND MAXIMA OF 150-200MM. ACROSS WESTERN  
PANAMA INITIALLY 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. ON FRIDAY EXPECT RAINFALL AMOUNTS OF 50-100MM/DAY AND  
MAXIMA OF 150-200MM. STORM TOTAL AMOUNTS BETWEEN COSTA RICA AND  
WESTERN PANAMA WILL RANGE BETWEEN 300-500MM...WITH LOCALLY HIGHER  
AMOUNTS HIGHLY PROBABLE.  
 
FURTHERMORE...AS THE POLAR TROUGH DEEPENS TO THE NORTH...IT IS TO  
SUSTAIN THE NORTHWARD AMPLIFICATION OF THE PANAMANIAN LOW/TROUGH  
ACROSS EASTERN PANAMA-GULF OF URABA TO THE SOUTHERN CARIBBEAN. THE  
TROUGH ANCHORS ON A CLOSED LOW JUST NORTH OF THE PANAMA CANAL/CITY  
OF COLON...WHERE IT IS TO PERSIST THROUGH AT LEAST THURSDAY. THE  
LOW/TROUGH IS ENHANCING LOW LEVEL MOISTURE CONVERGENCE ACROSS THE  
SOUTHERN CARIBBEAN...TO CONTRIBUTE TO THE AFOREMENTIONED HEAVY  
RAINS OVER SOUTHERN CENTRAL AMERICA. THIS TROUGH IS TO ALSO  
ENHANCE CONVECTIVE DEVELOPMENT ACROSS WESTERN COLOMBIA. ON THE  
WESTERN PLAINS AND ANDEAN REGION EXPECTING SCATTERED CONVECTION TO  
FAVOR RAINFALL AMOUNTS OF 05-10MM/DAY AND MAXIMA OF 15-25MM.  
 
AT 250 HPA...A HIGH OVER NORTHEAST VENEZUELA ANCHORS THE  
SUBEQUATORIAL RIDGE OVER THE EASTERN CARIBBEAN. AT 500 HPA A HIGH  
OVER THE CENTRAL ATLANTIC EXTENDS A RIDGE TO THE SOUTHWEST ACROSS  
THE LESSER ANTILLES TO THE EASTERN CARIBBEAN. THE MID LEVEL RIDGE  
SUSTAINS A TRADE WINDS CAP ACROSS THE NORTHEAST CARIBBEAN ISLES  
THAT IS INHIBITING ORGANIZED DEEP CONVECTION. SHORT WAVE  
PERTURBATIONS ROUNDING THE BASE OF THE MID/UPPER LEVEL TROUGH TO  
THE WEST ARE TO LIFT OVER THIS RIDGE. AT MID LEVELS THIS WILL  
EXERT ENOUGH PRESSURE TO FAVOR EROSION OF TRADE WINDS CAP ACROSS  
THE NORTHEAST CARIBBEAN ISLES BY MIDDAY ON THURSDAY...WITH FURTHER  
EROSION EXPECTED ON FRIDAY-SATURDAY. BUT LATER DURING THE WEEKEND  
THE RIDGE IS TO ONCE AGAIN STRENGTHEN...TO SUSTAIN A STRONG  
SUBSIDENCE INVERSION ACROSS THE EASTERN CARIBBEAN. 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...WITH PLUME OF  
MOISTURE LIFTING ACROSS THE VIRGIN ISLES AND PUERTO RICO. ALTHOUGH  
MOISTURE CONTENT INCREASES...BEST MOISTURE CONVERGENCE IS EXPECTED  
ALONG THE SURFACE FRONT TO THE NORTH AND WEST. THUS...ONLY  
EXPECTING LIGHT CONVECTION OVER THE ISLAND CHAIN-VIRGIN ISLES AND  
PUERTO RICO ON THURSDAY-FRIDAY. SLIGHTLY HIGHER AMOUNTS ARE  
EXPECTED ON SATURDAY AS THE FRONT STARTS TO RETROGRESS AND  
CONVECTION ACROSS HISPANIOLA STARTS TO WANE. CONVECTION FARTHER TO  
THE SOUTH IS EXPECTED ACROSS NORTHERN GUYANA-NORTHEAST  
VENEZUELA...WITH ACCUMULATION OF 00-05MM/DAY AND MAXIMA OF 10MM.  
OVER FRENCH GUIANA SEA BREEZE CONVERGENCE WILL FAVOR RAINFALL  
AMOUNTS OF 05-10MM/DAY AND MAXIMA OF 15MM/DAY.  
 
TROPICAL/EASTERLY WAVES INITIALIZED AT 12UTC:  
INITIAL 24 36 48 60 72 84 96 TYPE SOF  
62W 66W 68W 69W DISSIPATES TUTT INDCD 24N  
 
REMNANTS OF A TUTT INDUCED PERTURBATION IS INITIALIZED ALONG 62W  
TO 24N. OVER THE FRENCH-LEEWARD AND VIRGIN ISLES THIS IS TO  
SUSTAIN RAINFALL AMOUNTS OF 00-05MM/DAY AND MAXIMA OF 10MM. AS IT  
MOVES ACROSS PUERTO RICO ONLY EXPECTING LIGHT CONVECTION WITH  
ACCUMULATION OF 00-05MM/DAY IN WIDELY ISOLATED RAIN SHOWERS.  
 
GORDON...NMS (BELIZE)  
PECK...MS (JAMAICA)  
DAVISON...WPC (USA)  
 

 
 
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