Prognostic Meteorological Discussion
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FXCA20 KWBC 281835
PMDCA

TROPICAL DISCUSSION - INTERNATIONAL DESKS
NWS WEATHER PREDICTION CENTER COLLEGE PARK MD
234 PM EDT THU AUG 28 2014

DISCUSSION FROM AUGUST 28/00UTC: QUIET PATTERN IN MEXICO AS DRY
AIR MASS AND MID-LEVEL RIDGE REMAIN IN PLACE. MOST ACTIVITY WILL
CONCENTRATE ALONG THE PACIFIC COAST OF THE COUNTRY WHERE
DEEP-LAYER MOISTURE REMAINS IN PLACE. OTHER REGION OF LOCALLY
ENHANCED ACTIVITY WILL BE THE EXTREME NORTHEAST...AS LOW-LEVEL
CYCLONE AND TUTT PRODUCE NUMEROUS THUNDERSTORMS. LATER IN THE
CYCLE...A LARGE TROPICAL WAVE WILL ENTER THE REGION LEADING TO AN
INCREASE IN PRECIPITATION. THE WAVE WILL START AFFECTING THE
YUCATAN PENINSULA BY LATE ON SATURDAY...LEADING TO WIDESPREAD
MODERATE-TO HEAVY RAINS ON SUNDAY-MONDAY AND INTO TUESDAY. THROUGH
FRIDAY MORNING...EXPECTING MAXIMA OF 20-30MM/DAY IN EXTREME
NORTHEASTERN MEXICO...AND ALONG GUERRERO-MICHOACAN INTO NAYARIT.
ACROSS YUCATAN/TABASCO EXPECTING MAXIMA OF 20-40MM/DAY. BY FRIDAY
INTO EARLY SATURDAY...EXPECTING ISOLATED MAXIMA OF 30-60MM/DAY
ACROSS TAMAULIPAS/NUEVO LEON. ACROSS SOUTHWESTERN TIER EXPECTING
MAXIMA OF 20-40MM/DAY. AS ITCZ APPROACHES SOUTHERN
COAST...EXPECTING MAXIMA OF 40-80 IN OAXACA/CHIAPAS. BY
SATURDAY-EARLY SUNDAY...EXPECTING MAXIMA OF 40-80 SPREADING FROM
CHIAPAS/OAXACA INTO GUERRERO. AS TROPICAL WAVE
APPROACHES...EXPECTING MAXIMA OF 25-50MM/DAY ACROSS EASTERN
YUCATAN/BELIZE.

ACROSS THE BAHAMAS/NORTHERN CUBA...SCATTERED CONVECTION WILL
REMAIN UNDER INFLUENCE OF LOW-LEVEL TROUGH ASSOCIATED WITH
CRISTOBAL. THIS WILL LEAD TO MAXIMA OF 20-40MM/DAY ACROSS CUBA AND
15-25MM/DAY ACROSS THE NORTHERN BAHAMAS THROUGH FRIDAY MORNING.
DECREASING RAPIDLY AFTERWARDS.

IN THE CARIBBEAN...ACTIVITY WILL BE LARGELY MODULATED BY STRONG
WAVE IN THE TRADES. THIS WAVE WILL ENHANCE CONVECTION IN
HISPANIOLA AND ESPECIALLY JAMAICA ON THROUGH SATURDAY MORNING.
THROUGH FRIDAY MORNING...IT WILL LEAD TO MAXIMA OF 20-30MM/DAY. BY
FRIDAY-SATURDAY MORNING IT WILL LEAD TO MAXIMA OF
25-50MM/DAY...WITH AMOUNTS DECREASING AFTERWARDS. WAVE WILL ALSO
ENHANCE ACTIVITY ACROSS NORTHWESTERN COLOMBIA/LAKE MARACAIBO
REGION ON DAY 01 TO PRODUCE MAXIMA OF 25-50MM/DAY THROUGH FRIDAY
MORNING. A SHARP DECREASE EXPECTED AFTERWARDS WITH ISOLATED
CONVECTION DOMINATING MOST OF NORTHERN SOUTHAMERICA THROUGH LATE
CYCLE. ANOTHER SYSTEM OF INTEREST IS AN ILL-DEFINED TROPICAL WAVE
THAT WILL ENTER THE LESSER ANTILLES DURING THE DAY ON FRIDAY.
MODELS CONTINUE DIVERGING REGARDING ITS EVOLUTION...THUS WHAT WILL
HAPPEN IN TERMS OF ACCUMULATIONS/WAVE PROGRESSION IS STILL
SOMEWHAT UNCLEAR. STILL...EXPECTING ONLY LIMITED EFFECTS ON
PRECIPITATION WITH LARGEST AMOUNTS EXPECTED ACROSS PUERTO
RICO/LEEWARDS/VI...REACHING MAXIMA OF 15-25MM/DAY ON LATE FRIDAY
INTO SUNDAY.

ACTIVE PATTERN WILL DOMINATE CENTRAL AMERICA THROUGH THE CYCLE.
THIS IS ESPECIALLY TRUE ACROSS THE PACIFIC BASIN...WHERE SEA
SURFACE TEMPERATURES ARE REACHING THEIR HIGHEST VALUES...AND ITCZ
IS MEANDERING VERY CLOSE TO THE COAST. FURTHERMORE...A BROAD LOW
OVER THE EASTERN PACIFIC WILL LEAD TO AN EXTENDED PERIOD OF
SOUTHERLY/SOUTHWESTERLY FLOW. THIS WILL ENHANCE LOW-LEVEL MOISTURE
CONVERGENCE ALONG COASTAL AREAS LEADING TO LARGE RAINFALL AMOUNTS.
FINALLY...ROBUST TROPICAL WAVE APPROACHING FROM THE EAST WILL ALSO
LEAD TO AN ENHANCEMENT IN ACTIVITY. MODELS ARE VERY CONFIDENT
ABOUT LARGEST MOISTURE POOL/CONVECTIVE INSTABILITY BUILDING TO THE
NORTH AND CONCENTRATING IN THE GULF OF HONDURAS/YUCATAN
REGION...ESPECIALLY TOWARDS SATURDAY-MONDAY. THROUGH EARLY
FRIDAY...EXPECTING MAXIMA OF 35-70MM/DAY FROM NORTHWESTERN
NICARAGUA INTO GUATEMALA/CHIAPAS. OVER COSTA RICA/SOUTHERN
NICARAGUA EXPECTING MAXIMA OF 25-50MM/DAY. BY FRIDAY-EARLY
SATURDAY...EXPECTING MAXIMA OF 40-80MM/DAY FROM EL SALVADOR INTO
SOUTHERN MEXICO. OVER COSTA RICA EXPECTING MAXIMA OF 25-50MM/DAY.
OVER NICARAGUA/HONDURAS EXPECTING MAXIMA OF 20-40MM/DAY. ON
SATURDAY INTO SUNDAY EXPECTING MAXIMA OF 40-80MM/DAY ONCE AGAIN
FROM EL SALVADOR INTO SOUTHERN MEXICO. ACROSS HONDURAS/BELIZE
EXPECTING MAXIMA OF 25-50MM/DAY. TROPICAL WAVE WILL ALSO ENHANCE
AMOUNTS ACROSS THE CAYMANS/SOUTHERN CUBA PRODUCING MAXIMA OF
20-40MM/DAY.

TROPICAL/EASTERLY WAVES INITIALIZED AT 12UTC
INITIAL  24     36     48     60     72     84     96     TYPE
57W     59W    62W    64W    67W     69W   71W    73W     TW
69W     71W    74W    77W    81W     85W   87W    90W     TW

A TROPICAL WAVE ALONG 57W IS ILL-DEFINED AND APPROACHING THE
BASIN. MODELS ARE NOT SURE ABOUT HOW TO PROCEED WITH THIS
SYSTEM...AND ONLY THE GFS MOVES IT NORTHWESTWARD ACROSS PUERTO
RICO AND INTO THE OPEN ATLANTIC. BOTH THE ECMWF AND UKMET BRING
THE WAVE INTO THE CARIBBEAN BASIN PRODUCING ONLY LIMITED EFFECTS
IN PRECIPITATION. GIVEN CURRENT SOLUTIONS...IT APPEARS LIKELY THAT
WAVE WILL ONLY ENHANCE MAXIMA TO VALUES IN THE ORDER OF
15-25MM/DAY AS IT MOVES ACROSS THE LEEWARDS AND PUERTO RICO.

A MUCH MORE ROBUST TROPICAL WAVE IS ORGANIZING AS IT CROSSES THE
CENTRAL CARIBBEAN AT 69W. THIS WAVE WILL ENHANCE CONVECTION AND
ACCUMULATIONS PRIMARILY ACROSS SOUTHERN HISPANIOLA THROUGH FRIDAY
MORNING...AND THEN CONCENTRATE ACROSS SOUTHERN HISPANIOLA/JAMAICA
DURING FRIDAY INTO SATURDAY...JAMAICA/SOUTHERN CUBA/CAYMAN ISLANDS
AND EASTERN HONDURAS DURING SATURDAY-SUNDAY...AND THEN PRIMARILY
ACROSS HONDURAS/BELIZE/YUCATAN...WHERE IT WILL LIKELY PRODUCE
MODERATE TO HEAVY RAINFALL AMOUNTS AFTERWARDS. SEE ABOVE FOR
ACCUMULATIONS.

VALVERDE...IMN (COSTA RICA)
MEDINA...ONAMET (REPUBLICA DOMINICANA)
GALVEZ...WPC (USA)
$$




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