180  
FXCA20 KWBC 161846  
PMDCA  
 
TROPICAL DISCUSSION - INTERNATIONAL DESKS  
NWS WEATHER PREDICTION CENTER COLLEGE PARK MD  
245 PM EDT MON OCT 16 2017  
 
TROPICAL DISCUSSION FROM OCT 16/06 UTC: SURFACE COLD FRONT EXTENDS  
ACROSS THE NORTHERN GULF OF MEXICO. BY MONDAY EVENING...THE TAIL  
OF THE FRONT WILL EXTEND INTO SOUTHERN TAMAULIPAS WHILE AN  
ILL-DEFINED SHEAR LINE EXTENDS ACROSS THE NORTHERN  
BAHAMAS...WESTERN CUBA...INTO THE CENTRAL YUCATAN PENINSULA. BY  
TUESDAY EVENING...THE FRONT WILL LIMIT OFFSHORE THE COAST OF  
TAMAULIPAS...WHILE THE ILL-DEFINED SHEAR LINE MEANDERS ACROSS THE  
NORTHERN BAHAMAS...WESTERN CUBA AND THE YUCATAN PENINSULA. BY  
WEDNESDAY EVENING...THE TAIL OF THE FRONT WILL BE WEAKENING JUST  
TO THE NORTH OF THE NORTHERN BAHAMAS-NORTHEASTERN GULF OF MEXICO.  
THE EVENT IS ALSO ACCOMPANIED BY A NORTHERLY WIND SURGE ACROSS THE  
WESTERN GULF OF MEXICO. THIS WILL ENHANCE OROGRAPHIC PRECIPITATION  
IN EASTERN MEXICO ALONG NORTHERN SLOPES...AND WILL ALSO CONTINUE  
LEADING TO THE DEVELOPMENT OF A TEHUANTEPECER LOW-LEVEL JET.  
THROUGH EARLY TUESDAY...LARGEST ACCUMULATIONS ARE EXPECTED IN  
SOUTHERN VERACRUZ WHERE ENHANCED OROGRAPHIC UPLIFT WILL LEAD TO  
20-40MM/DAY AND MAXIMA OF 50-100MM. IN NORTHERN VERACRUZ/NORTHERN  
PUEBLA/HIDALGO EXPECTING 15-20MM/DAY AND MAXIMA OF 25-50MM. ALSO  
DURING THIS PERIOD...SHEAR LINE CONVECTION WILL LEAD TO  
10-15MM/DAY AND MAXIMA OF 20-35MM IN THE YUCATAN PENINSULA AND IN  
NORTHERN GUATEMALA AND BELIZE. BY TUESDAY-WEDNESDAY...EXPECTING  
LARGEST ACCUMULATIONS IN TABASCO/NORTHERN CHIAPAS...WHERE  
OROGRAPHIC FORCING WILL SUSTAIN 15-30MM/DAY AND MAXIMA OF 35-70MM.  
SHEAR LINE CONVERGENCE WILL CONTINUE STIMULATING PRECIPITATION IN  
THE YUCATAN PENINSULA TO SUSTAIN 10-15MM/DAY AND MAXIMA OF  
20-35MM. BY WEDNESDAY THROUGH EARLY THURSDAY...LARGEST  
ACCUMULATIONS ARE EXPECTED IN SOUTHERN VERACRUZ/TABASCO...WHERE  
EXPECTING 15-20MM/DAY AND MAXIMA OF 25-50MM. REMNANT INSTABILITY  
IN THE YUCATAN PENINSULA...AND IN NORTHERN CENTRAL AMERICA WILL  
CONTINUE BEING SUBJECT TO ENHANCED OROGRAPHIC UPLIFT FROM THE  
NORTHEASTERLY TRADES. THIS WILL SUSTAIN 10-15MM/DAY AND MAXIMA OF  
20-40MM. NOTE THAT THERE WILL BE ALSO CONTRIBUTION BY THE  
APPROACHING TROPICAL WAVE. ALSO IN ASSOCIATION WITH THE  
FRONT...ACTIVITY IN THE NORTHERN BAHAMAS HAS THE POTENTIAL OF  
PRODUCING 15-20MM/DAY AND MAXIMA OF 25-50MM.  
 
ONGOING WET SPELL IN THE EASTERN CARIBBEAN WILL CONTINUE THROUGH  
WEDNESDAY. DURING WEDNESDAY...A TRADE WIND SURGE IS FORECAST TO  
ARRIVE FROM THE TROPICAL ATLANTIC. MODELS ARE SHOWING A MARKED  
DRYING...WHICH WILL RESULT IN A SHARP DECREASE IN CLOUD COVER AND  
PRECIPITATION. IN THE MEAN TIME...ACTIVITY IS CLUSTERING IN TWO  
REGIONS. ONE OF THEM IS WITH THE ITCZ...WHICH IS LOCATED UNUSUALLY  
TO THE NORTH OF ITS CLIMATOLOGICAL POSITION...ENTERING THE LESSER  
ANTILLES NEAR BARBADOS/SAINT LUCIA. THE OTHER REGION IS HISPANIOLA  
AND PUERTO RICO...WHICH IS ALSO UNDER THE INFLUENCE OF A MOIST  
PLUME AND IS FEELING THE ENHANCEMENT OF AN UPPER TROUGH MEANDERING  
TO THE EAST OF THE BAHAMAS. IN THE LESSER ANTILLES...UNDER THE  
INFLUENCE OF THE ITCZ...AND A TROPICAL WAVE TO CROSS THE ISLANDS  
ON MONDAY NIGHT...EXPECTING RAINFALL AMOUNTS OF 15-30MM/DAY AND  
MAXIMA OF 35-70MM FROM MARTINIQUE INTO THE VIRGIN ISLANDS. BY  
TUESDAY-EARLY WEDNESDAY...EXPECTING ACTIVE CONVECTION TO  
CONTINUE...WITH AMOUNTS OF 15-20MM/DAY AND MAXIMA OF 30-60MM FROM  
TRINIDAD AND TOBAGO...NORTH INTO GUADELOUPE. IN THE VIRGIN  
ISLANDS...EXPECTING A DECREASE TO 10-15MM/DAY AND MAXIMA OF  
20-35MM. BY WEDNESDAY-THURSDAY...AMOUNTS WILL DECREASE SHARPLY IN  
THE NORTHERN LESSER ANTILLES UNDER THE INFLUENCE OF THE TRADE WIND  
SURGE. HOWEVER...ITCZ CONVECTION WILL CONTINUE STIMULATING  
PRECIPITATION IN THE WINDWARD ISLANDS AND NORTHEASTERN  
VENEZUELA...WHERE EXPECTING 15-30MM/DAY AND MAXIMA OF 35-70MM.  
 
IN HISPANIOLA...MONDAY CONVECTION WILL LEAD TO 15-30MM/DAY AND  
MAXIMA OF 35-70MM WHILE IN PUERTO RICO EXPECTING 05-10MM/DAY AND  
MAXIMA OF 15-20MM. BY TUESDAY-WEDNESDAY...EXPECTING 15-20MM/DAY  
AND MAXIMA OF 25-50MM IN HISPANIOLA WHILE IN PUERTO RICO  
ACCUMULATIONS ARE TO INCREASE TO 10-15MM/DAY AND MAXIMA OF  
20-30MM. BY WEDNESDAY EXPECTING A SIGNIFICANT DRYING IN PUERTO  
RICO...WHILE IN HISPANIOLA EXPECTING A NEW INCREASE IN  
ACCUMULATIONS UNDER THE INFLUENCE OF THE TROPICAL WAVE AND THE  
CONVERGENCE AHEAD OF A LOW-LEVEL JET FROM THE SOUTHEAST. THIS WILL  
LEAD TO 15-30MM/DAY AND MAXIMA OF 40-80MM MOSTLY IN THE DOMINICAN  
REPUBLIC. LESSER AMOUNTS ARE EXPECTED IN HAITI.  
 
IN NORTHERN SOUTH AMERICA...LARGEST ACCUMULATIONS ARE TO CLUSTER  
IN WESTERN VENEZUELA AND COLOMBIA...GENERALLY ALONG THE NET...AND  
WILL ALSO BE STIMULATED BY A CROSSING TROPICAL WAVE. UNDER THE  
INFLUENCE OF THE WAVE (SEE BELOW)...THE PANAMANIAN LOW IS FORECAST  
TO ORGANIZE ON TUESDAY. THIS WILL LEAD TO AN ENHANCEMENT OF  
ACTIVITY ACROSS WESTERN COLOMBIA AND PANAMA ON TUESDAY AND INTO  
WEDNESDAY. ON MONDAY...LARGEST AMOUNTS ARE EXPECTED IN CENTRAL  
VENEZUELA/EASTERN COLOMBIA TO REACH 10-15MM/DAY AND MAXIMA OF  
20-30MM...WHILE IN WESTERN COLOMBIA AND PANAMA EXPECTING  
05-10MM/DAY AND MAXIMA OF 15-25MM. BY  
TUESDAY-WEDNESDAY...EXPECTING LARGEST ACCUMULATIONS ALONG THE NET  
IN WESTERN VENEZUELA TO CENTRAL/WESTERN COLOMBIA AND  
PANAMA...WHERE EXPECTING 10-15MM/DAY AND MAXIMA OF 20-30MM.  
ALSO...TROPICAL WAVE CONVECTION WILL ENHANCE ACCUMULATIONS IN  
EASTERN NICARAGUA/EASTERN COSTA RICA AND THE CARIBBEAN  
ISLANDS...TO SUSTAIN 10-15MM/DAY AND MAXIMA OF 20-30MM. BY  
WEDNESDAY...AS THE TROPICAL WAVE CROSSES WESTERN VENEZUELA...THIS  
WILL CONTINUE SUSTAINING AMOUNTS OF 10-15MM/DAY AND MAXIMA OF  
20-35MM.  
 
TROPICAL/EASTERLY WAVES INITIALIZED AT 12UTC:  
INITIAL 24 36 48 60 72 84 96 TYPE SOF  
56W 58W 61W 63W 66W 69W 72W 75W TW 18N  
74W 76W 79W 82W 84W 87W 90W 92W TW 18N  
 
TROPICAL WAVE AT 56W IS PROPAGATING AHEAD OF A TRADE WIND SURGE.  
THE WAVE WILL REINFORCE CURRENT WET PATTERN IN THE LESSER  
ANTILLES. IT WILL CROSS THE ISLANDS LATE ON MONDAY/EARLY ON  
TUESDAY TO SUSTAIN ACCUMULATIONS OF 15-30MM/DAY AND MAXIMA OF  
35-70MM/DAY. BY TUESDAY-WEDNESDAY...TRAILING MOISTURE PLUME BEHIND  
THE WAVE WILL CONTINUE STIMULATING ACCUMULATIONS ACROSS THE LESSER  
ANTILLES TO PRODUCE 15-20MM/DAY AND MAXIMA OF 30-60MM. IN PUERTO  
RICO AND THE VIRGIN ISLANDS EXPECTING 10-15MM/DAY AND MAXIMA OF  
20-35MM. LIGHTER ACCUMULATIONS ARE EXPECTED IN VENEZUELA WHILE  
MOISTURE AVAILABILITY REMAINS LIMITED. ISOLATED MAXIMA OF 30-60MM  
IS POSSIBLE IN EXTREME NORTHEASTERN VENEZUELA. BY WEDNESDAY-EARLY  
THURSDAY...THE WAVE WILL ENHANCE ACCUMULATIONS IN THE DOMINICAN  
REPUBLIC TO SUSTAIN 15-30MM/DAY AND MAXIMA OF 40-80MM. IN COLOMBIA  
AND WESTERN VENEZUELA THIS WILL SUSTAIN MAXIMA OF 20-35MM.  
 
TROPICAL WAVE IS INITIALIZED AT 74W. THE WAVE IS ILL-DEFINED AS IT  
HAS INTERACTED WITH THE UPPER LOW/TROUGH LOCATED NEAR THE BAHAMAS.  
THE WAVE IS...HOWEVER...FORECAST TO REORGANIZE AND STIMULATE  
ACTIVITY ACROSS COLOMBIA AND CENTRAL AMERICA...AND JAMAICA TO A  
LESSER EXTENT. THROUGH EARLY TUESDAY...IN COLOMBIA AND  
PANAMA...EXPECTING 05-10MM/DAY AND MAXIMA OF 15-25MM. IN JAMAICA  
EXPECTING 05-10MM/DAY AND ISOLATED MAXIMA OF 15-20MM. BY  
TUESDAY-EARLY WEDNESDAY...EXPECTING ENHANCED ACTIVITY IN  
PANAMA/EASTERN COSTA RICA/AND EASTERN NICARAGUA WITH ACCUMULATIONS  
OF 10-15MM/DAY AND MAXIMA OF 20-30MM. BY WEDNESDAY-THURSDAY...THE  
WAVE WILL CONTINUE STIMULATING AMOUNTS IN EASTERN  
NICARAGUA/EASTERN HONDURAS TO SUSTAIN 10-15MM/DAY AND MAXIMA OF  
20-40MM. AS THE WAVE APPROACHES THE YUCATAN PENINSULA...WHERE  
ENHANCED INSTABILITY WILL BE IN PLACE...IT WILL HELP TO SUSTAIN  
SIMILAR ACCUMULATIONS.  
 
GUY...NMS (BELIZE)  
PECK...MS (JAMAICA)  
GALVEZ...WPC (USA)  

 
 
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