THE WEATHER PREDICTION CENTER

COLLEGE PARK, MD


CARIBBEAN FORECAST DISCUSSION




TROPICAL DISCUSSION - INTERNATIONAL DESKS
NWS WEATHER PREDICTION CENTER COLLEGE PARK MD
153 PM EST FRI DEC 19 2014

DISCUSSION FROM DECEMBER 19/00UTC: A CLOSED MID LEVEL HIGH OVER
THE YUCATAN PENINSULA EXTENDS A RIDGE ACROSS THE CARIBBEAN BASIN
TO NORTHERN SOUTH AMERICA. AMPLIFYING TROUGH OVER THE WESTERN
USA/NORTHERN MEXICO IS TO SUSTAIN GRADUAL EROSION OF THIS RIDGE
OVER WESTERN PORTIONS OF THE DOMAIN LATER DURING THE WEEKEND. BUT
PORTION OVER THE CARIBBEAN-NORTHERN SOUTH AMERICA IS TO GENERALLY
PERSIST WELL INTO THE MEDIUM RANGE PERIOD. AS THE RIDGE WEAKENS TO
THE WEST...CLOSED HIGH IS TO GRADUALLY RELOCATE TO PUERTO RICO
EARLY ON SUNDAY MORNING. THE STRONG MID LEVEL RIDGE SUSTAINS A
SUBSIDENCE CAP INVERSION ACROSS THE BASIN. THIS IS TO PERSIST OVER
THE NEXT FEW DAYS...MEANWHILE CAPPING MOISTURE TO LOWER LEVELS OF
THE ATMOSPHERE. AT LOW LEVELS THIS IS TO SUSTAIN A RIDGE NORTH OF
THE GREATER ANTILLES THAT IS FORECAST TO GRADUALLY BUILD THROUGH
SUNDAY EVENING. THIS RIDGE...AS IT MEANDERS TO THE NORTH OF THE
GREATER ANTILLES...IS TO SUSTAIN BRISK EASTERLY WINDS ACROSS THE
BASIN. OVER THE NORTHERN CARIBBEAN ISLANDS THE WINDS ARE TO PEAK
AT 10-15KT...WHILE OVER THE SOUTHERN CARIBBEAN THE WINDS INCREASE
FROM 20-25KT EARLY IN THE CYCLE TO 30-35KT LATER ON SUNDAY.
SHALLOW CLOUD CLUSTERS ARE TO EMBED IN THIS FLOW...TO SUSTAIN
PERIODS OF LIGHT CONVECTION AS THEY ADVECT ACROSS THE LESSER
ANTILLES INTO PUERTO RICO-DOMINICAN REPUBLIC. BUT FOR THE MOST
PART ARE TO ONLY FAVOR LIGHT TO TRACE RAINFALL AMOUNTS.

AS PREVIOUSLY INDICATED...A DIGGING MID/UPPER LEVEL TROUGH MOVES
ACROSS THE WESTERN USA LATER ON SATURDAY...AND THROUGH SUNDAY
EVENING IT AMPLIFIES ACROSS THE CENTRAL USA TO TEXAS/NORTHEASTERN
MEXICO. FURTHER AMPLIFICATION OF THIS AXIS IS THEN EXPECTED
THROUGH THE MIDDLE OF NEXT WEEK. AT LOW LEVELS A SURFACE FRONT IS
TO MEANDER ACROSS THE NORTHERN GULF OF MEXICO TO SOUTHERN
TEXAS/NORTHERN TAMAULIPAS OVER THE NEXT FEW DAYS...WITH A STRONGER
BOUNDARY TO SURGE ACROSS THE GULF/GULF COAST OF MEXICO ON TUESDAY
TO WEDNESDAY. MEANWHILE...AS IT MEANDERS TO THE NORTH...THIS IS TO
FAVOR LIGHT RAINFALL ACROSS TAMAULIPAS/COAHUILA WITH ACCUMULATION
OF 00-05MM. HIGHER AMOUNTS... HOWEVER...ARE EXPECTED ACROSS THE
YUCATAN PENINSULA...WHERE UNDER INFLUENCE OF A PREFRONTAL TROUGH
EXPECTING SCATTERED CONVECTION ACROSS BELIZE-QUINTANA ROO THROUGH
SATURDAY MORNING TO RESULT IN RAINFALL AMOUNTS OF 05-10MM/DAY AND
MAXIMA OF 15-25MM. ON SATURDAY TO SUNDAY THE MAXIMA INCREASES TO
15-30MM IN SCATTERED CONVECTION. THROUGH SUNDAY THE FOCUS OF THE
CONVECTION SHIFTS TO CAMPECHE/TABASCO-YUCATAN...WITH RAINFALL
AMOUNTS OF 05-10MM/DAY AND MAXIMA OF 15MM.

STRONG MID/UPPER LEVEL RIDGE PATTERN...AS IT STRENGTHENS THE TRADE
WINDS CAP...SUSTAINS THE RAPID EROSION OF AVAILABLE MOISTURE
ACROSS THE SOUTHERN CARIBBEAN-NORTHERN SOUTH AMERICA. ACROSS
PANAMA-COSTA RICA EXPECTING LIGHT CONVECTION WITH RAINFALL AMOUNTS
OF 00-05MM/DAY AND WIDELY ISOLATED MAXIMA OF 10MM. ITCZ
CONVERGENCE OVER COLOMBIA WILL LIMIT TO EJE CAFETERO/THE CAUCA
VALLEY...WITH RAINFALL AMOUNTS OF 00-05MM/DAY AND MAXIMA OF 10MM
OVER EJE CAFETERO...AND 05-10MM/DAY AND ISOLATED MAXIMA OF 15-20MM
ON THE CAUCA/CAUCA VALLEY TO THE SOUTH. THE ATLANTIC
ITCZ...MEANWHILE...MEANDERS ACROSS THE TROPICAL ATLANTIC TO THE
SOUTHERN GUIANAS-AMAZONIA IN SOUTHERN VENEZUELA. A SOUTHERN
HEMISPHERE TUTT IS INTERACTING WITH THE CONVERGENCE
ZONE...FAVORING A SURGE IN ACTIVITY TO THE EAST OF 50W. THROUGH
SATURDAY EVENING MOISTURE SURGES WEST INTO FRENCH
GUIANA...EXPANDING ACROSS SURINAME DURING THE DAY ON SUNDAY.
CONVECTION ALONG THE COAST IS TO RESULT IN ACCUMULATION OF
05-10MM/DAY WITH MAXIMA OF 15-30MM BETWEEN NORTHERN SURINAME AND
EASTERN FRENCH GUIANA. THIS THEN BUILDS WEST TO NORTHERN GUYANA
WHERE IT IS TO SUSTAIN 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

NONE.

JN BAPTISTE...MS (SAINT LUCIA)
NANDA...MDS (SURINAME)
DAVISON...WPC (USA)




Last Updated: 153 PM EST FRI DEC 19 2014