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Tropical Discussion
 
(Latest Discussion - Issued 1800Z Oct 01, 2014)
 
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TROPICAL DISCUSSION - INTERNATIONAL DESKS
NWS WEATHER PREDICTION CENTER COLLEGE PARK MD
200 PM EDT WED OCT 01 2014

DISCUSSION FROM OCTOBER 01/00UTC: POLAR TROUGH MOVES ACROSS THE
WESTERN TO CENTRAL USA THROUGH THURSDAY EVENING...THEN ACROSS THE
MISSISSIPPI VALLEY LATER ON FRIDAY. THIS IS TO SUSTAIN A FRONT
ACROSS TEXAS TO THE RIO BRAVO EARLY ON FRIDAY MORNING...AND ACROSS
NORTHERN FLORIDA-GULF OF MEXICO TO TAMAULIPAS EARLY ON SATURDAY.
FURTHERMORE...THE PROGRESSIVE FRONT IS TO SUSTAIN A PREFRONTAL
SHEAR LINE ACROSS VERACRUZ MEXICO ON FRIDAY AFTERNOON/EVENING. AS
THE FRONT ENTERS NORTHEAST MEXICO IT IS TO SUSTAIN RAINFALL
AMOUNTS OF 10-15MM/DAY AND MAXIMA OF 20-40MM. MOST ACTIVE IS
EXPECTED WITH THE SHEAR LINE...TO SUSTAIN RAINFALL AMOUNTS OF
15-20MM/DAY AND MAXIMA OF 35-70MM.

AS THE POLAR TROUGH MOVES ACROSS THE USA...IT IS GOING TO PRESS
AGAINST A CELL OF THE SUBTROPICAL RIDGE TO THE SOUTH. AT 250 HPA
THE RIDGE IS TO EXTEND WEST FROM CENTRAL/SOUTHERN MEXICO...ACROSS
THE GULF-FLORIDA/THE BAHAMAS TO NORTH OF THE GREATER ANTILLES.
UPPER RIDGE PATTERN IS TO ANCHOR ON TWO CLOSED HIGHS...WITH ONE AT
23N 103W AND THE OTHER AT 23N 89W. AS POLAR TROUGH AMPLIFIES
ACROSS THE CENTRAL-EASTERN USA...RIDGE OVER THE GULF IS TO
WANE...WHILE THE ONE OVER MEXICO BUILDS NORTH AND WEST. RIDGE
ALOFT IS TO VENT DEEP CONVECTION ACROSS MEXICO. MOST ACTIVE IS
EXPECTED TO THE SOUTHWEST IN ASSOCIATION WITH A TROPICAL
WAVE/TROPICAL DISTURBANCE ALONG THE EASTERN PACIFIC ITCZ. NHC IS
MONITORING THIS FEATURE FOR POSSIBLE TROPICAL CYCLONE FORMATION
OVER THE NEXT FEW DAYS. ACROSS NAYARIT-COLIMA TO GUERRERO
EXPECTING RAINFALL AMOUNTS OF 15-30MM/DAY AND MAXIMA OF 40-80MM
THROUGH THURSDAY EVENING. THIS THEN DECREASES TO 15-20MM/DAY AND
MAXIMA OF 25-50MM. ON THE SOUTHERN STATES OF MEXICO TO SOUTHERN
GUATEMALA EXPECTING RAINFALL AMOUNTS OF 15-20MM/DAY AND MAXIMA OF
25-50MM THROUGH WEDNESDAY EVENING...AND 05-10MM/DAY AND MAXIMA OF
15-20MM THEREAFTER. OTHER ACTIVITY IS EXPECTED ALONG THE SIERRA
MADRE BETWEEN SINALOA-SONORA...WITH RAINFALL AMOUNTS OF
05-10MM/DAY AND MAXIMA OF 15-20MM. OVER BELIZE-NORTHERN GUATEMALA
TO THE YUCATAN... MEANWHILE... EXPECTING ACCUMULATION OF
05-10MM/DAY AND MAXIMA OF 15-20MM.

UPPER RIDGE PATTERN NORTH OF THE GREATER ANTILLES IS TO PERSIST
OVER THE NEXT FEW DAYS. AT MID LEVELS...ANOTHER RIDGE EXTENDS
WEST-TO-EAST ACROSS THE GREATER ANTILLES. THIS RIDGE SUSTAINS A
TRADE WINDS CAP ACROSS HISPANIOLA-NORTHEAST CARIBBEAN ISLES. AS
THE RIDGE PATTERN HOLDS...AND PHASES WITH UPPER RIDGE PATTERN TO
THE NORTH...THE AREA OF SUBSIDENCE IS TO BUILD WEST ACROSS
CUBA/THE BAHAMAS-JAMAICA AND THE CAYMAN ISLES. ACROSS CUBA THIS IS
TO FAVOR A GRADUAL DRYING TREND THROUGH FRIDAY. EARLY IN THE CYCLE
THE MOST ACTIVE IS TO CLUSTER BETWEEN CENTRAL-WESTERN CUBA WITH
ACCUMULATION OF 05-10MM/DAY AND MAXIMA OF 15-20MM. THROUGH
THURSDAY THIS DECREASES TO 00-05MM/DAY AND MAXIMA OF 10MM. ACROSS
THE NORTHWEST BAHAMAS...MEANWHILE... EXPECT ACCUMULATION OF
05-10MM/DAY AND MAXIMA OF 15MM THROUGH FRIDAY AFTERNOON.

SOUTH OF THE SUBTROPICAL RIDGE...A TUTT EXTENDS WEST ACROSS THE
SOUTHERN CARIBBEAN...WITH AXIS ACROSS THE FRENCH ILSES-13N 70W TO
A LOW NORTH OF LA GUAJIRA PENINSULA/SOUTHERN CARIBBEAN. THIS
TROUGH IS TO GENERALLY CONFINE TO THE UPPER LEVELS OF THE
ATMOSPHERE...HAVING LITTLE TO NO IMPACT/REFLECTION AT MID LEVELS.
AS A RESULT...ANY CONVECTIVE ENHANCEMENT IS TO GENERALLY LIMIT TO
NORTHERN SOUTH AMERICA...WHERE IN INTERACTION WITH THE NEAR
EQUATORIAL TROUGH OVER NORTHERN COLOMBIA-NORTHWEST VENEZUELA IT IS
TO FAVOR SCATTERED CONVECTION. IN THIS AREA EXPECTING RAINFALL
AMOUNTS OF 10-15MM/DAY AND MAXIMA OF 20-40MM...WITH LOCALLY HIGHER
AMOUNTS POSSIBLE IN ASSOCIATION WITH TROPICAL WAVE (SEE BELOW FOR
DETAILS). ACROSS SOUTHERN NICARAGUA-COSTA RICA AND
PANAMA...MEANDERING ITCZ IS TO ALSO FAVOR SCATTERED CONVECTION
WITH ACCUMULATION OF 05-10MM/DAY AND MAXIMA OF 15-25MM. THIS
INCREASES TO 20-35MM LATER ON THURSDAY-FRIDAY.

TROPICAL/EASTERLY WAVES INITIALIZED AT 12UTC
INITIAL  24     36     48     60     72     84     96     TYPE
60W     64W    68W    71W    74W    77W    78W    80W     TW
91W     93W    95W    97W    98W   100W   102W   104W     TW
103W   104W   106W   107W   108W   110W   112W   115W     TW

TROPICAL WAVE ALONG 60W IS MOVING TO THE CONVERGENT SIDE OF MID
LEVEL RIDGE ENVELOPING THE NORTHEAST CARIBBEAN ISLES. AS A
RESULT...EXPECTING MOSTLY SHALLOW CONVECTION AS IT PULLS ACROSS
THE LEEWARD/VIRGIN ISLES...WITH RAINFALL AMOUNTS OF 00-05MM/DAY
AND MAXIMA OF 10MM. HIGHER AMOUNTS ARE EXPECTED ON THE WINDWARD
ISLES/NORTHEAST VENEZUELA...WHERE IN INTERACTION WITH THE ATLANTIC
ITCZ EXPECTING ACCUMULATION OF 05-10MM/DAY AND MAXIMA OF 15MM.
FOLLOWING WAVE PASSAGE...DRY/DUSTY CONDITIONS ARE TO ESTABLISH AS
A SAL ENTERS THE BASIN LATER THIS WEEK. ACROSS CENTRAL HISPANIOLA
EXPECTING RAINFALL AMOUNTS OF 05-10MM/DAY AND MAXIMA OF 15MM.
SIMILAR AMOUNTS ARE EXPECTED OVER JAMAICA-EASTERN CUBA ON FRIDAY.
OVER CENTRAL VENEZUELA EXPECTING ACCUMULATION OF 05-10MM/DAY AND
MAXIMA OF 15-25MM...WHILE OVER NORTHWEST VENEZUELA/NORTHERN
COLOMBIA IN INTERACTION WITH TUTT ALOFT EXPECTING RAINFALL AMOUNTS
OF 10-15MM/DAY AND MAXIMA OF 20-35MM. HIGHER AMOUNTS OVER WESTERN
COLOMBIA ARE EXPECTED ON THURSDAY TO FRIDAY...WITH ACCUMULATION OF
15-20MM/DAY AND MAXIMA OF 25-50MM.

WEAK TROPICAL WAVE EXTENDS ALONG 91W TO SOUTHERN MEXICO. THIS IS
ENHANCING CONVECTIVE DEVELOPMENT ON THE SOUTHERN STATES OF
MEXICO...WHERE WE EXPECT RAINFALL AMOUNTS OF 15-20MM/DAY AND
MAXIMA OF 25-50MM. OVER OAXACA-GUERRERO-CENTRAL STATES OF MEXICO
IT IS TO THEN FAVOR RAINFALL AMOUNTS OF 10-15MM/DAY AND MAXIMA OF
20-40MM.

TROPICAL WAVE ALONG 103W SUSTAINS AN AREA OF DISTURBED WEATHER
ALONG THE EASTERN PACIFIC ITCZ...WITH THE NHC FORECASTING HIGH
RISK OF TROPICAL CYCLONE FORMATION OVER THE NEXT COUPLE OF DAYS.
THIS IS ENHANCING ONSHORE FLOW ACROSS THE SOUTHWEST STATES OF
MEXICO...BETWEEN COLIMA/NAYARIT AND GUERRERO...WHERE STRONG
TOPOGRAPHICAL FORCING IS TO SUSTAIN RAINFALL AMOUNTS OF
15-30MM/DAY AND MAXIMA OF 40-80MM THROUGH THURSDAY. AS IT MOVES
WEST...AND A MOIST PLUME EXPANDS ACROSS SOUTHERN BAJA
PENINSULA...THIS IS TO THEN FAVOR RAINFALL AMOUNTS OF 00-05MM/DAY
AND MAXIMA OF 10MM LATER ON FRIDAY.

JN BAPTISTE...MS (SAINT LUCIA)
MEDINA...ONAMET (REPUBLICA DOMINICANA)
DAVISON...WPC (USA)