Prognostic Meteorological Discussion
Issued by NWS

Home | Current Version | Previous Version | Text Only | Print | Product List | Glossary On
Versions: 1
000
FXCA20 KWBC 291853
PMDCA

TROPICAL DISCUSSION - INTERNATIONAL DESKS
NWS WEATHER PREDICTION CENTER COLLEGE PARK MD
253 PM EDT FRI APR 29 2016

TROPICAL DISCUSSION FROM APRIL 29/12UTC: LARGE UPPER MID-UPPER
RIDGE DOMINATES NORTHERN CENTRAL AMERICA AND SOUTHERN MEXICO. THE
RIDGE IS FORECAST TO MEANDER TO THE WEST-NORTHWEST THROUGH THE
CYCLE. THIS WILL GRADUALLY ENHANCE UPPER VENTILATION AND LIMIT
MID-LEVEL SUBSIDENCE OVER CENTRAL AMERICA. AT LOW-LEVELS MODELS
CONTINUE RESOLVING WEAK SOUTH/SOUTH WESTERLIES ACROSS THE PACIFIC
COAST. THIS WILL CONTINUE ENHANCING LOW-LEVEL MOISTURE CONVERGENCE
ALONG THE WEST COAST FROM COSTA RICA NORTHWEST INTO THE GULF OF
FONSECA/EL SALVADOR/SOUTHERN GUATEMALA. BETWEEN EL SALVADOR AND
GUATEMALA/CHIAPAS EXPECTING DIURNAL MAXIMA OF 20-30MM/DAY. BETWEEN
THE GULF OF FONSECA/WESTERN NICARAGUA/COSTA RICA EXPECTING DIURNAL
MAXIMA OF 20-40MM/DAY.

PERSISTENT UPPER TROUGH PATTERN WILL CONTINUE DOMINATING THE
CENTRAL AND EASTERN CARIBBEAN. THROUGH FRIDAY THE TROUGH WILL
EXTEND ITS AXIS ACROSS THE DOMINICAN REPUBLIC SOUTH INTO THE LAKE
MARACAIBO REGION. BY SATURDAY EVENING IT WILL EXTEND ACROSS THE
VIRGIN ISLANDS INTO NORTH-CENTRAL VENEZUELA WHILE ANOTHER SHORT
WAVE TROUGH AXIS APPROACHES FROM THE NORTHWEST ACROSS SE CUBA. BY
SUNDAY EVENING THE SECOND TROUGH WILL DOMINATE AND MODELS FORECAST
A TROUGH AXIS RESTRUCTURING ACROSS THE MONA PASSAGE SOUTH INTO THE
LAKE MARACAIBO REGION. THIS EVOLUTION WILL SUSTAIN AN UPPER
DIVERGENT PATTERN IN AREAS TO THE SOUTHEAST OF THE TROUGH AXIS. IN
INTERACTION WITH MOIST AND UNSTABLE AIR MASS AT LOW
LEVELS...EXPECTING ACTIVE CONVECTION ACROSS THE DOMINICAN
REPUBLIC/PUERTO RICO THROUGH SUNDAY. AT LOW-LEVELS AN INDUCED
TROUGH IS FORECAST TO EXTEND ACROSS THE DOMINICAN REPUBLIC INTO
THE GUAJIRA PENINSULA THROUGH THE CYCLE. SCATTERED THUNDERSTORMS
ARE TO PRODUCE ACCUMULATIONS OF 15-20MM/DAY AND MAXIMA OF 35-70MM
ACROSS HISPANIOLA AND PUERTO RICO ON FRIDAY INTO EARLY SATURDAY.
AMOUNTS ARE TO INCREASE TO 25-50MM/DAY AND MAXIMA OF 75-125MM BY
SATURDAY INTO EARLY SUNDAY. A DECREASE IN ACTIVITY IS EXPECTED
AFTER...WITH MAXIMA OF 30-60MM/DAY ACROSS SOUTHEASTERN HISPANIOLA.
ACTIVE DIURNAL CONVECTION IS ALSO EXPECTED IN WESTERN PARTS OF
HISPANIOLA WITH MAXIMA USUALLY NEAR OR BELOW 30MM/DAY.

UNUSUALLY ACTIVE CONVECTION WILL CONTINUE IN VENEZUELA AND THE
GUIANAS THROUGH THE WEEKEND...PEAKING THROUGH SATURDAY/EARLY
SUNDAY. THIS IS THE RESULT OF A COMBINATION OF SEVERAL FACTORS
SUCH AS A SOUTHERN HEMISPHERE SHEAR LINE...THE ITCZ/NET DISPLACED
TO THE NORTH OF ITS CLIMATOLOGICAL POSITION...AND VENTILATION TO
THE SOUTH AND EAST OF THE AFOREMENTIONED UPPER TROUGH. THROUGH
EARLY SATURDAY STRONGEST CONVECTION WILL ORGANIZE BETWEEN SOUTHERN
GUYANA INTO MOST OF CENTRAL AND SOUTHERN/SOUTHEASTERN VENEZUELA
WHERE EXPECTING 25-50MM/DAY AND MAXIMA OF 75-125MM. NET CONVECTION
ALONG THE COASTS OF THE GUIANAS WILL LEAD TO MAXIMA OF
25-50MM/DAY. ACCUMULATIONS ARE TO PEAK ON SATURDAY AIDED BY THE
DIVERGENT ENTRANCE OF AN UPPER JET...ESPECIALLY OVER
EASTERN...CENTRAL VENEZUELA/GUYANA WHERE EXPECTING AMOUNTS OF
30-60MM/DAY AND MAXIMA OF 100-150MM. AMOUNTS WILL DECREASE
AFTER...BUT ACTIVE CONVECTION WILL STILL PRODUCE SCATTERED MAXIMA
OF 40-80MM/DAY ACROSS MOST OF VENEZUELA. NET/ITCZ CONVECTION IS
ALSO EXPECTED DURING SUNDAY INTO MONDAY TO PRODUCE MAXIMA OF
25-50MM/DAY ACROSS THE GUIANAS.

SEASONALLY ACTIVE CONVECTION IS EXPECTED ACROSS ANDEAN/WESTERN
COLOMBIA AND PANAMA IN ASSOCIATION WITH THE ITCZ/NET AND PLENTIFUL
MOISTURE. EXPECTING DIURNAL THUNDERSTORMS TO PRODUCE DAILY AMOUNTS
IN THE ORDER OF 10-15MM/DAY AND MAXIMA OF 20-40MM/DAY.

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

CARDOS...SMN (MEXICO)
CABANERIT...INAMEH (VENEZUELA)
DAVISON/GALVEZ...WPC (USA)
$$





USA.gov is the U.S. government's official web portal to all federal, state and local government web resources and services.