Prognostic Meteorological Discussion
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FXCA20 KWBC 221747
PMDCA

TROPICAL DISCUSSION - INTERNATIONAL DESKS
NWS WEATHER PREDICTION CENTER COLLEGE PARK MD
147 PM EDT TUE APR 22 2014

DISCUSSION FROM APRIL 22/00UTC: DIURNAL CONVECTION IS ACTIVATING
ACROSS MEXICO IN RESPONSE TO HIGHER MOISTURE AVAILABILITY AND
SOLAR RADIATION. MOST ACTIVE DIURNAL SHOWERS AND THUNDERSTORMS ARE
EXPECTED ACROSS THE SOUTHERN SIERRA MADRE ORIENTAL AND SOUTHERN
MEXICO...WHERE THEY WILL PRODUCE ACCUMULATIONS OF 10-15MM/DAY AND
ISOLATED MAXIMA OF 20-30MM/DAY TODAY INTO WEDNESDAY MORNING.
ELSEWHERE IN CENTRAL MEXICO EXPECTING 05-10MM/DAY AND MAXIMA OF
15MM IN THUNDERSTORMS. EXPECTING A GENERAL DECREASING TREND
THROUGH THE CYCLE...WITH DIURNAL CONVECTION PERSISTING ESPECIALLY
ACROSS CENTRAL MEXICO INTO OAXACA. ACROSS NORTHERN CENTRAL
AMERICA...EXPECTING ISOLATED DIURNAL CONVECTION ACROSS
GUATEMALA/WESTERN HONDURAS AND EL SALVADOR. ISOLATED AMOUNTS WILL
APPROACH 20-30MM/DAY THROUGH THURSDAY MORNING. DURING THURSDAY
AFTERNOON INTO LATE ON FRIDAY EXPECTING A MORE ACTIVE PATTERN WITH
MORE WIDESPREAD AFTERNOON THUNDERSTORMS AND MAXIMA INCREASING TO
20-35MM/DAY.

TAIL OF FRONT LOCATED TO THE NORTH OF HISPANIOLA IS STALLING WHILE
WEAKENING. ASSOCIATED REMAINING CONVECTIVE INSTABILITY WILL LINGER
IN THE AREA THROUGH THE CYCLE. THIS WILL ALLOW FOR ENHANCED
DIURNAL SHOWERS AND THUNDERSTORMS ACROSS THE NORTHWESTERN HALF OF
HISPANIOLA...SOUTHEASTERN CUBA AND THE SOUTHEASTERN BAHAMAS
THROUGH THURSDAY MORNING. AFTERWARDS...FRONT WILL REORGANIZE AS
NEW NORTHERLY SURGE ARRIVES IN FROM THE NORTH.
NEVERTHELESS...MODELS ARE NOT MOVING THE FRONT TOO FAR TO THE
SOUTH BUT MAINLY JUST STRENGTHENING LOW-LEVEL MOISTURE
CONVERGENCE. AS THE FRONT STRENGTHENS...EXPECTING ALSO A
RE-STRENGTHENING OF THE SHEAR LINE. THIS WILL RESULT IN AN
INCREASE IN ACCUMULATIONS OVER HISPANIOLA BY LATE CYCLE. DURING
TUESDAY INTO EARLY WEDSNESDAY...EXPECTING MOST ACTIVE CONVECTION
TO LINGER ACROSS SOUTHEASTERN CUBA-NORTHERN HAITI-NORTHERN
DOMINICAN REPUBLIC TO PRODUCE ACCUMULATIONS OF 05-10MM/DAY AND
MAXIMA OF 15-30MM. EXPECTING A SLIGHT DECREASE ON WEDNESDAY INTO
THURSDAY. A NEW INCREASE DURING THURSDAY INTO FRIDAY WILL PRODUCE
10-15MM/DAY AND ISOLATED MAXIMA OF 20-35MM.

THE FRENCH ANTILLES ARE EXPERIENCE A TRANSIENT WET PATTERN AS THEY
ARE UNDER THE INFLUENCE OF A REGION OF ENHANCED TRADE WIND
CONVERGENCE. FURTHERMORE...ACTIVITY IS BEING ENHANCED AS IT LIES
ON THE BASE OF A WEAKENING TUTT LOCATED IN THE TROPICAL ATLANTIC.
THIS WILL LEAD TO SCATTERED SHOWERS ACROSS THE LEEWARD ISLANDS AND
FRENCH ANTILLES THROUGH WEDNESDAY MORNING WITH ACCUMULATIONS OF
05-10MM/DAY AND MAXIMA OF 15-30MM. AMOUNTS ARE TO DECREASE
AFTERWARDS AS MID-LEVEL RIDGE STRENGTHENS AND A DRYNG TREND
ESTABLISHES.

CENTRAL AMERICA IS EXPERIENCING A GRADUAL ACTIVATION OF DIURNAL
CONVECTION. YET...MOST ACTIVE WILL REMAIN CONSTRAINED TO SOUTHERN
COSTA RICA AND PANAMA UNDER INDIRECT INFLUENCE OF ITCZ AND
FORMIDABLE VENTILATION. CONVECTION IS ORGANIZING WEAKLY ALONG
ILL-DEFINED PERTURBATIONS IN THE TRADES. ONE IS EXITING THE
CONTINENT TO THE WEST OF COSTA RICA...WHICH WILL LEAD TO A
DECREASE IN ACCUMULATIONS THROUGH WEDNESDAY. STILL EXPECTING
ISOLATED MAXIMA OF 15-20MM. EXPECTING A NEW INCREASE AFTER FRIDAY.

VENTILATION OVER NORTHERN SOUTH AMERICA WILL CONTINUE ENHANCED IN
THE PERIPHERY OF UPPER HIGHS. CONVECTIVE INSTABILITY IS ALSO
FORECAST TO REMAIN HIGH THROUGH THE CYCLE...WHICH WILL CONTINUE
SUSTAINING WIDESPREAD DEEP CONVECTION ACROSS THE REGION. MOST
ACTIVE WILL EXTEND FROM NORTHERN ECUADOR THROUGH MOST OF COLOMBIA
INTO NORTHWESTERN VENEZUELA WITH GENERALIZED MAXIMA OF 30-60MM/DAY.

GALVEZ...WPC (USA)
GARCIA...SMN (MEXICO)
FIGUEROA...MARN (EL SALVADOR)
$$





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