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Tropical Discussion
 
(Latest Discussion - Issued 1848Z May 10, 2021)
 
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TROPICAL DISCUSSION - INTERNATIONAL DESKS
NWS WEATHER PREDICTION CENTER COLLEGE PARK MD
248 PM EDT MON MAY 10 2021

TROPICAL DISCUSSION FROM MAY 10/19 UTC: IN THE UPPER LEVELS...A
LARGE TROUGH EXTENDS FROM THE BAHAMAS INTO PANAMA...WHILE DIVIDING
A RIDGE CENTERING TO THE SOUTH OF MEXICO NEAR 15N 99W...AND A CELL
OF THE SUBEQUATORIAL RIDGE CENTERING NEAR 09N 56W. THE UPPER
TROUGH IS FORECAST TO WEAKEN AND ACQUIRE A SOUTHWEST-NORTHEAST
TILT THROUGH THE CYCLE...TO EXTEND FROM HISPANIOLA INTO WESTERN
PANAMA/COSTA RICA BY WEDNESDAY EVENING. THIS WILL PROVIDE
ENHANCEMENT TO CONVECTION OCCURRING IN SOUTHERN CENTRAL AMERICA
AND COLOMBIA...AND TO A LESSER EXTENT TO CONVECTION IN
HISPANIOLA/JAMAICA...GIVEN THE LIMITED AMOUNTS OF AVAILABLE
MOISTURE IN THE NORTHERN CARIBBEAN.

IN THE NORTHERN BASIN...A SURFACE FRONT IS MEANDERING ALONG THE
SOUTHERN UNITED STATES ON MONDAY. THE FRONT IS FORECAST TO START
MEANDERING SOUTHWARD LATE ON TUESDAY ACROSS SOUTHERN TEXAS INTO
THE RIO BRAVO REGION. BY WEDNESDAY EVENING IT IS FORECAST TO
EXTEND ACROSS NORTH FLORIDA...CENTRAL GULF OF MEXICO...INTO
NORTHERN VERACRUZ/SAN LUIS POTOSI IN MEXICO.
INITIALLY...CONVECTION WILL CONCENTRATE IN THE RIO BRAVO REGION TO
SUSTAIN 05-10MM/DAY AND MAXIMA OF 15MM ON MONDAY. ON
TUESDAY...UNDER THE INFLUENCE OF AN UPPER TROUGH...EXPECT AN
INCREASE TO 10-15MM/DAY AND MAXIMA OF 20-35MM WITH THE RISK OF
SEVERITY. ON WEDNESDAY...ENHANCED MOISTURE CONVERGENCE ASSOCIATED
WITH NORTHEASTERLY LOW-LEVEL WINDS WILL SUSTAIN MODERATE
PRECIPITATION ALONG THE SIERRA MADRE ORIENTAL AND COAST OF
NORTHEAST MEXICO TO SUSTAIN AMOUNTS OF 15-20MM/DAY AND MAXIMA OF
35-70MM. ALSO ON WEDNESDAY...ACTIVE CONVECTION IS EXPECTED IN
EASTERN PORTIONS OF THE MEXICAN PLATEAU AND EJE VOLCANICO
TRANSVERSAL CENTRAL WHERE EXPECTING 10-15MM/DAY AND MAXIMA OF
20-35MM. REMNANT CONVECTION IN COAHUILA.

ALSO IN MEXICO...DIURNAL CONVECTION IS EXPECTED ON A DAILY BASIS
IN CENTRAL MEXICO...IN ASSOCIATION WITH VENTILATION IN THE
NORTHERN PERIPHERY OF THE UPPER RIDGE TO PRODUCE 05-10MM/DAY AND
MAXIMA OF 15-25MM IN CENTRAL MEXICO ON MONDAY...INCREASING TO
10-15MM/DAY AND MAXIMA OF 20-35MM ON EASTERN PORTIONS OF THE
MEXICAN PLATEAU AND SIERRA MADRE ORIENTAL ON TUESDAY.

IN THE CARIBBEAN...THE UPPER TROUGH WILL BE THE DOMINANT FEATURE
TO ENHANCE CONVECTION IN THE GREATER ANTILLES IN COMBINATION WITH
EASTERLY WAVES. FURTHERMORE...TRADE WINDS ARE FORECAST TO REMAIN
UNUSUALLY ACCELERATED FOR THE TIME OF THE YEAR...PARTLY IN
ASSOCIATION WITH THE UPPER CONVERGENT PHASE OF THE MADDEN JULIAN
OSCILLATION. ENHANCED LOW-LEVEL SHEAR AND LIMITED AVAILABLE
MOISTURE WILL LIMIT POTENTIAL ACCUMULATIONS WITH SUCH UPPER
TROUGH. ON MONDAY...EXPECT THE LARGEST AMOUNTS IN HISPANIOLA WHERE
EXPECTING 10-15MM/DAY AND MAXIMA OF 20-35MM STIMULATED ALSO BY AN
INDUCED TROUGH. IN PUERTO RICO EXPECT SCATTERED MAXIMA OF 15MM. IN
JAMAICA AND SOUTHEAST CUBA...EXPECT 05-10MM/DAY AND MAXIMA OF 15MM
STIMULATED BY AN EASTERLY WAVE. ON TUESDAY...EXPECT 05-10MM/DA AND
MAXIMA OF 15-25MM IN HISPANIOLA...STIMULATED BY AN EASTERLY WAVE.
IN PUERTO RICO...CUBA AND JAMAICA EXPECT ONCE AGAIN 05-10MM/DAY
AND MAXIMA OF 15MM. ON WEDNESDAY...EXPECT A SIGNIFICANT DRYING
TREND IN THE GREATER ANTILLES...AS THE INFLUENCE OF A MID-LEVEL
RIDGE INCREASES OVER MOST OF THE NORTHERN CARIBBEAN. AREAS OF
SCATTERED PRECIPITATION WILL CONFINE TO CUBA AND THE BAHAMAS WHERE
EXPECTING MAXIMA OF 10MM.

MUCH LARGER ACCUMULATIONS ARE EXPECTED IN SOUTHERN CENTRAL
AMERICA...WHERE ENHANCEMENT BY THE UPPER TROUGH IS EXPECTED TO BE
MUCH MORE SIGNIFICANT. ON MONDAY...EXPECT 10-15MM/DAY AND MAXIMA
OF 20-45MM IN COSTA RICA/WESTERN PANAMA...WHILE IN EASTERN
NICARAGUA EXPECT 05-10MM/DAY AND MAXIMA OF 15MM IN RESPONSE TO
ENHANCED TRADE WIND CONVERGENCE. ON TUESDAY...EXECTING A LARGER
AREA OF AMOUNTS IN THE ORDER OF 10-15MM/DAY AND MAXIMA OD 20-40MM
IN COSTA RICA AND SOUTHEAST NICARAGUA...STIMULATED BY AN EASTERLY
WAVE AND THE CYCLONIC EXIT OF THE CARIBBEAN LOW-LEVEL JET. IN
PANAMA AND WESTERN COSTA RICA EXPECT 05-10MM/DAY AND MAXIMA OF
15-25MM. ON WEDNESDAY...EXPECT 10-15MM/DAY AND MAXIMA OF 20-35MM
FROM SOUTHERN NICARAGUA INTO WESTERN PANAMA...STIMULATED BY
ANOTHER EASTERLY WAVE. TO THE NORTH BETWEEN NORTHERN NICARAGUA AND
CHIAPAS...EXPECT 05-10MM/DAY AND MAXIMA OF 15-25MM.

IN NORTHERN SOUTH AMERICA...EXPECT A DRYING TREND AS A STABLE AND
DRIER AIR MASS ENTERS FROM THE CARIBBEAN ACROSS VENEZUELA....AND
AS THE UPPER FLOW PATTERN BECOMES LESS DIVERGENT.
INITIALLY...EXPECT 15-20MM/DAY AND MAXIMA OF 25-50MM ALONG THE NET
IN WESTERN COLOMBIA...AND CENTRAL/EASTERN COLOMBIA/SOUTHERN
VENEZUELA...WHILE IN THE SOUTHERN GUIANAS EXPECT MAXIMA OF
20-40MM. ON TUESDAY...THE LARGEST AMOUNTS ARE EXPECTED FROM
SOUTHERN GUIANA INTO SOUTHERN VENEZUELA IN ASSOCIATION WITH AN
EASTERLY WAVE. IN CENTRAL AND WESTERN COLOMBIA...AND THE
COLOMBIAN/WESTERN VENEZUELA ORINOQUIA EXPECT 10-15MM/DAY AND
MAXIMA OF 20-35MM. ON WEDNESDAY...EXPECT 10-15MM/DAY AND MAXIMA OF
20-45MM IN THE SOUTHERN GUIANAS WHILE IN SOUTHERN VENEZUELA AND
EASTERN COLOMBIA EXPECT 10-15MM/DAY AND MAXIMA OF 20-35MM.

TROPICAL WAVES/TUTT INDUCED PERTURBATIONS/TRADE WIND SURGES
INITIALIZED AT 12 UTC.
TYPE   INIT   F24   F36   F48   F60   F72   F84   F96  SOF

GALVEZ...WPC (USA)