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Tropical Discussion
 
(Caution: Version displayed is not the latest version. - Issued 1914Z Feb 20, 2015)
 
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TROPICAL DISCUSSION - INTERNATIONAL DESKS
NWS WEATHER PREDICTION CENTER COLLEGE PARK MD
214 PM EST FRI FEB 20 2015

DISCUSSION FROM FEBRUARY 20/00UTC: MID/UPPER LEVEL PATTERN IS TO
EVOLVE OVER THE NEXT FEW DAYS...WITH RIDGE FORECAST TO RAPIDLY
BUILD FROM MEXICO ACROSS THE CARIBBEAN BASIN TO NORTHERN SOUTH
AMERICA THROUGH SUNDAY. AS THE RIDGE BUILDS...IT IS TO DISPLACE A
POLAR TROUGH TO THE NORTH. EARLY IN THE CYCLE THE TROUGH IS TO
EXTEND ACROSS THE EASTERN USA/WESTERN ATLANTIC TO THE NORTHERN
CARIBBEAN. BUT THROUGH MIDDAY ON SATURDAY THE TROUGH IS EXPECTED
TO RAPIDLY PULL. BUILDING RIDGE IS TO THEN STRENGTHEN THE TRADE
WINDS CAP ACROSS THE CARIBBEAN...FAVORING A GRADUAL EROSION OF
AVAILABLE MOISTURE ACROSS MOST OF THE BASIN THROUGHOUT THE WEEKEND.

AT LOW LEVELS...POLAR FRONT EXTENDS ACROSS HAITI/NORTHWEST
DOMINICAN REPUBLIC-JAMAICA TO NORTHERN HONDURAS...WITH FRONTAL
NORTHERLIES OF 25-30KT ACROSS NORTHERN HISPANIOLA AND 15-20KT OVER
THE NORTHWEST CARIBBEAN. BOUNDARY IS TO REMAIN NEARLY STATIONARY
THROUGH EARLY SATURDAY MORNING. BUT AS THE PREVAILING EASTERLIES
RETURN TO THE BASIN...TRAILING END IS TO RAPIDLY RETROGRESS ACROSS
THE NORTHWEST CARIBBEAN TO CUBA LATER ON SATURDAY...MEANDERING TO
THE CENTRAL BAHAMAS EARLY ON SUNDAY WHERE THE BOUNDARY IS FORECAST
TO DISSIPATE. AS THE POLAR TROUGH MEANDERS OVER THE WESTERN
ATLANTIC IT IS TO SUSTAIN AN INDUCED/PREFRONTAL TROUGH ACROSS THE
EASTERN CARIBBEAN. THIS FAVORS A MOIST SOUTHEASTERLY FLOW ACROSS
THE ISLAND CHAIN TO PUERTO RICO/VIRGIN ISLES... WHERE PWAT IS
FORECAST TO PEAK AT 25-35MM. THIS IS TO ALSO WEAKEN THROUGH MIDDAY
ON SATURDAY AS POLAR TROUGH PULLS AND PREVAILING EASTERLIES RETURN
TO THE BASIN. AS THE FRONT MEANDERS OVER NORTHERN HISPANIOLA THIS
WILL COMBINE WITH STRONG NORTHERLY WINDS TO FAVOR ORGANIZED HEAVY
CONVECTION...WITH RAINFALL AMOUNTS OF 25-50MM/DAY AND MAXIMA OF
75-150MM THROUGH SATURDAY MORNING. SOUTH OVER THE ISLAND...LESSER
AMOUNTS ARE EXPECTED WITH ACCUMULATION OF 05-10MM/DAY AND MAXIMA
OF 15MM. ACROSS JAMAICA EXPECTING RAINFALL AMOUNTS OF 05-10MM/DAY
AND MAXIMA OF 15MM...WHILE OVER NORTHERN HONDURAS IT IS TO FAVOR
RAINFALL AMOUNTS OF 05-10MM/DAY AND MAXIMA OF 15-25MM. AS THE
FRONT RETROGRESSES ACROSS CUBA TO THE BAHAMAS IT IS TO THEN FAVOR
RAINFALL AMOUNTS OF 00-05MM/DAY AND WIDELY ISOLATED MAXIMA OF
10MM. THE INDUCED/INVERTED TROUGH OVER THE EASTERN
CARIBBEAN...MEANWHILE...IS TO FAVOR LIGHT TO MODERATE CONVECTION
ACROSS THE LEEWARD-VIRGIN ISLES TO PUERTO RICO...WITH ACCUMULATION
OF 05-10MM/DAY AND MAXIMA OF 15MM.

FURTHERMORE...THE SURFACE FRONT SUSTAINS A PREFRONTAL SHEAR LINE
ACROSS THE DOMINICAN REPUBLIC TO PANAMA. THIS IS TO REMAIN NEARLY
STATIONARY THROUGH EARLY MORNING HOURS ON SATURDAY...THEN
RETROGRESSES TO COSTA RICA/NICARAGUA BY DAYBREAK. THROUGH SATURDAY
EVENING...HOWEVER...IT IS TO BECOME ILL DEFINED. AS THE SHEAR LINE
WEAKENS/DISSIPATES A MOIST PLUME IS TO THEN DETACH FROM THIS
AXIS...TO PROPAGATE TO THE NORTHWEST CARIBBEAN/YUCATAN PENINSULA
LATER IN THE CYCLE. MEANWHILE...AS THE SHEAR LINE MEANDERS OVER
SOUTHERN CENTRAL AMERICA THIS IS TO FAVOR RAINFALL AMOUNTS OF
10-15MM/DAY AND MAXIMA OF 20-40MM THROUGH SATURDAY MORNING. ACROSS
EASTERN NICARAGUA/NORTHEAST HONDURAS IT IS TO THEN FAVOR RAINFALL
AMOUNTS OF 05-10MM/DAY AND MAXIMA OF 15-20MM. AS THE MOIST PLUME
LIFTS ACROSS THE WESTERN CARIBBEAN TO THE YUCATAN IT IS TO THEN
FAVOR ISOLATED TO SCATTERED SHALLOW CONVECTION. OVER
BELIZE-QUINTANA ROO IN THE YUCATAN EXPECTING ACCUMULATION OF
05-10MM/DAY AND MAXIMA OF 15MM.

NEXT POLAR FRONT MOVES ACROSS THE SOUTHERN USA TO THE MEXICO
BORDER LATER ON SUNDAY/EARLY MONDAY MORNING. LATER ON MONDAY IT IS
TO MEANDER INTO THE GULF OF MEXICO WHILE TRAILING TO NORTHEAST
MEXICO. AS IT MEANDERS ACROSS THE RIO BRAVO TO NORTHEAST MEXICO
THIS IS TO ONLY FAVOR LIGHT TO TRACE AMOUNTS.

SOUTH OVER THE DOMAIN...STRONG NORTHERLIES ACROSS PANAMA-COSTA
RICA OVER THE LAST COUPLE OF DAYS INDUCED UPWELLING OF COLD WATER
ON THE PACIFIC COASTAL WATERS INTO WESTERN COLOMBIA. NORTHERLY
WINDS ARE TO WANE OVER THE NEXT COUPLE OF DAYS...WITH SEA SURFACE
TEMPERATURES TO GRADUALLY RETURN TO NORMAL. AS THE PACIFIC COASTAL
WATERS WARM UP...AND TRADES WEAKEN... CONVECTION ALONG THE COASTAL
PLAINS/ANDEAN REGION OF COLOMBIA IS TO INCREASE. INITIALLY MOST
ACTIVE CONVECTION IS EXPECTED OVER SOUTHWEST COLOMBIA...WITH
RAINFALL AMOUNTS OF 00-05MM/DAY AND MAXIMA OF 10MM. THROUGH SUNDAY
DIURNAL CONVECTION BUILDS NORTHWARD ALONG THE ANDES OF
COLOMBIA/EJE CAFETERO TO FAVOR RAINFALL AMOUNTS OF 05-10MM/DAY AND
MAXIMA OF 15MM. ON MONDAY THIS IS EXPECTED TO PEAK AT 15-25MM.

ACROSS THE GUIANAS...LIGHT CONVECTION IS TO CLUSTER ALONG THE
NORTH COAST OVER THE NEXT DAY. BUT AS A SOUTHERN HEMISPHERE TUTT
LOW RETROGRESSES ACROSS NORTHEAST BRASIL THIS IS TO THEN FAVOR A
MOIST PLUME ACROSS THE NORTHERN GUIANAS. THIS WILL THEN SUSTAIN AN
INCREASE IN ACTIVITY...WITH CONVECTION TO RANGE BETWEEN
05-10MM/DAY AND MAXIMA EXPECTED TO PEAK AT 15MM/DAY.

TROPICAL/EASTERLY WAVES INITIALIZED AT 12UTC
INITIAL  24     36     48     60     72     84     96     TYPE
NONE

CRAIG...TTMS (TRINIDAD AND TOBAGO)
NANDA...MDS (SURINAME)
DAVISON...WPC (USA)