Prognostic Meteorological Discussion
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TROPICAL DISCUSSION - INTERNATIONAL DESKS
NWS WEATHER PREDICTION CENTER COLLEGE PARK MD
246 PM EDT THU JUL 31 2014

DISCUSSION FROM JULY 31/00UTC: TUTT LOW IS MEANDERING
NORTHWESTWARD ALONG THE PACIFIC COAST OF THE BAJA CALIFORNIA
PENINSULA. IN THE MEAN TIME...AN UPPER RIDGE WILL CONTINUE
CENTERING ACROSS EXTREME WESTERN TEXAS ASSOCIATED WITH A SEASONAL
ACTIVATION OF THE NORTH AMERICAN MONSOON. TUTT MEANDERING IN THE
PERIPHERY OF THE RIDGE WILL PROVIDE EXCELLENT VENTILATION FOR
STRONG DIURNAL CONVECTION ALONG THE SIERRA MADRE OCCIDENTAL.
ACCUMULATIONS ARE TO EXTEND INTO NORTHERN CHIHUAHUA AS WELL. ON
THURSDAY INTO FRIDAY EXPECTING AMOUNTS OF 15-20MM/DAY AND MAXIMA
OF 35-70MM...WITH MAXIMA DECREASING TO 30-60MM ON FRIDAY THROUGH
SUNDAY. ACCUMULATIONS ARE ALSO EXPECTED IN THE LOWLANDS OF SONORA
AND PARTS OF BAJA CALIFORNIA SUR WITH MAXIMA OF 15-20MM/DAY
THROUGH SATURDAY. ACROSS NORTHERN COAHUILA...EXPECTING MAXIMA OF
15-25MM/DAY.

ELSEWHERE IN MEXICO...EXPECTING A RATHER WEAK PATTERN OF DIURNAL
CONVECTION TO CONSTRAIN TO THE EJE VOLCANICO AND THE SIERRA MADRE
DEL SUR. CONVECTION WILL BE PRIMARILY DIURNAL WITH ISOLATED
ACCUMULATIONS 10-15MM/DAY AND MAXIMA OF 20-35MM. ISOLATED DIURNAL
CONVECTION IS ALSO EXPECTED IN YUCATAN TO PRODUCE MAXIMA OF
15-25MM EARLY IN THE CYCLE. AN INCREASE IS EXPECTED BY SATURDAY
INTO SUNDAY AS TUTT APPROACHES.

TO THE EAST...TRAIN OF TUTT LOWS IS DOMINATING THE SCENE. ONE OVER
THE NORTHWESTERN CARIBBEAN WILL CENTER OVER THE SOUTHERN GULF OF
HONDURAS ON DAY 01...TO THEN REORGANIZE AND MEANDER JUST OFF THE
COAST OF QUINTANA ROO IN YUCATAN. ALTHOUGH CONVECTION ACROSS
NORTHERN CENTRAL AMERICA IS EXPERIENCING A TRANSIENT QUIET
PATTERN...EXPECTING A SLIGHT INCREASE INTO SATURDAY AS TUTT
APPROACHES. EXPECTING ISOLATED CONVECTION TO PRODUCE ACCUMULATIONS
OF 05-10MM/DAY AND MAXIMA  OF 15-20MM.

TUTT WILL ALSO AID DIURNAL CONVECTION ACROSS MOST OF WESTERN CUBA
THROUGH THE CYCLE. CONVECTION WILL BE STIMULATED FURTHERMORE ON
SATURDAY AND INTO SUNDAY ANOTHER TUTT AND TUTT-INDUCED WAVE IN THE
TRADES APPROACH FROM THE EAST. CONVECTIVE INSTABILITY IS ALSO
GRADUALLY INCREASING. OVER CUBA EXPECTING DIURNAL CONVECTION TO
PRODUCE MAXIMA OF 20-35MM THROUGH FRIDAY...WITH MAXIMA INCREASING
TO 25-50MM/DAY ON FRIDAY-SATURDAY...AND TO 35-70MM/DAY SATURDAY
INTO SUNDAY. THE SECOND TUTT AND ASSOCIATED WAVE IN THE TRADES
WILL MODULATE CONVECTION ACROSS THE BAHAMAS/EASTERN CUBA/JAMAICA
AND HISPANIOLA THROUGH SATURDAY. ON THURSDAY INTO
FRIDAY...EXPECTING HEAVIEST PRECIPITATION TO AFFECT HISPANIOLA
WITH ACCUMULATIONS OF 10-15MM/DAY AND MAXIMA OF 20-35MM. ON FRIDAY
INTO SATURDAY EXPECTING 05-10MM/DAY AND MAXIMA OF 20-40MM. DURING
SATURDAY INTO SUNDAY EXPECTING LARGEST AMOUNTS ACROSS THE BAHAMAS
EXPECTING AMOUNTS OF 05-10MM/DAY AND MAXIMA OF 15-30MM TO PERSIST.
OVER JAMAICA...EXPECTING MORE ISOLATED ACCUMULATIONS THROUGH THE
CYCLE.

THE EASTERN CARIBBEAN WILL BE UNDER THE INFLUENCE OF A TROPICAL
DISTURBANCE LOCATED TO THE EAST OF BARBADOS. SEE NHC WEBSITE FOR
UPDATES ON THIS SYSTEM. PRECIPITATION ASSOCIATED WITH THIS SYSTEM
AND ASSOCIATED WAVE IN THE TRADES WILL ENHANCE ACCUMULATIONS FROM
THE LESSER ANTILLES INTO PUERTO RICO AND POSSIBLY THE DOMINICAN
REPUBLIC. ON FRIDAY INTO SATURDAY EXPECTING AMOUNTS OF 15-20MM/DAY
AND MAXIMA OF 40-80MM ACROSS THE CENTRAL AND NORTHERN LESSER
ANTILLES. ON SATURDAY INTO SUNDAY...EXPECTING LARGEST AMOUNTS
ACROSS EASTERN PUERTO RICO/VIRGIN ISLANDS REACHING 25-50MM/DAY AND
MAXIMA OF 75-125MM. ACROSS EXTREME EASTERN HISPANIOLA AND THE
LEEWARD ISLES EXPECTING ISOLATED MAXIMA OF 25-50MM.

ACROSS CENTRAL AMERICA...MOST ACTIVE IS EXPECTED ACROSS COSTA RICA
AND PANAMA WHILE MORE QUIET AND DRY CONDITIONS DOMINATE THE
NORTHERN TIER. AMOUNTS ARE TO GRADUALLY INCREASE THROUGH SATURDAY
AS PANAMANIAN LOW ACTIVATES AND CONVECTIVE INSTABILITY INCREASES.
EXPECTING AMOUNTS OF 15-20MM/DAY AND MAXIMA OF 25-50MM INCREASING
TO MAXIMA OF 35-70MM ON SATURDAY...TO AFFECT COSTA RICA/PANAMA AND
NORTHWESTERN COLOMBIA.

ACROSS NORTHERN SOUTH AMERICA...SEASONAL CONVECTION HAS ACTIVATED
OVER VENEZUELA AIDED FURTHERMORE BY WAVES IN THE TRADES (SEE
BELOW). CONVECTION WILL BE STIMULATED FURTHERMORE BY THE INDIRECT
EFFECTS OF AFOREMENTIONED DISTURBANCE AFFECTING THE EASTERN
CARIBBEAN. THIS WILL ENHANCE MOISTURE CONVERGENCE INTO THE WEEKEND
TO LEAD AN INCREASE IN AMOUNTS TO 10-15MM/DAY AND MAXIMA OF
20-40MM.

TROPICAL/EASTERLY WAVES INITIALIZED AT 12UTC
INITIAL  24     36     48     60     72     84     96     TYPE
50W     53W    56W    59W    63W    67W    70W     73W    TW
66W     69W    71W    73W    75W    77W    79W     81W    TUTT
INDUCED
74W     75W    77W    79W    DISSIP                       TUTT
INDUCED
104W   107W   110W   113W   116W   119W   122W    125W    TW

THE TROPICAL WAVE ALONG 50W REMAINS THE SYSTEM OF CONCERN. SEE NHC
FOR DETAILS ON THIS SYSTEM. THIS SYSTEM WILL PRODUCE RAINS ACROSS
THE CENTRAL/NORTHERN LESSER ANTILLES AND PUERTO RICO DURING THE
WEEKEND.

A TUTT INDUCED PERTURBATION ON THE EASTERLY TRADES HAS ITS AXIS
NORTH ALONG 66W. LARGEST EFFECTS WITH THIS WAVE WILL BE ALONG THE
DOMINICAN REPUBLIC ON FRIDAY...AND EASTERN CUBA/BAHAMAS ON
SATURDAY. SEE ABOVE FOR ACCUMULATIONS.

ANOTHER TUTT INDUCED PERTURBATION IS INITIALIZED ALONG 74W. THIS
IS FORECAST TO WEAKEN EARLY ON SATURDAY MORNING...STILL ALLOWING
FOR AFTERNOON CONVECTION IN HISPANIOLA. WAVE WILL ALSO AID
CONVECTION ACROSS PANAMA WHILE WEAKENING.

TROPICAL WAVE ALONG 104W IS AIDING CONVECTION ACROSS SOUTHWESTERN
MEXICO BUT EFFECTS IN CONTINENTAL AREAS DECREASING RAPIDLY.

VALVERDE...IMN (COSTA RICA)
DAVISON...WPC (USA)
GALVEZ...WPC (USA)
$$




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