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Tropical Discussion
 
(Latest Discussion - Issued 1536Z Oct 17, 2014)
 
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TROPICAL DISCUSSION - INTERNATIONAL DESKS
NWS WEATHER PREDICTION CENTER COLLEGE PARK MD
1136 AM EDT FRI OCT 17 2014

DISCUSSION FROM OCTOBER 17/00UTC: POLAR TROUGH OFF THE EASTERN
SEABOARD OF THE USA CONTINUES TO LIFT TO THE NORTHWEST AS ANOTHER
TROUGH DEEPENS FARTHER TO THE WEST. THE LATTER QUICKLY PULLS
ACROSS THE EASTERN USA THROUGH SATURDAY EVENING AND LATER ON
SUNDAY STARTS TO LIFT OVER THE WESTERN ATLANTIC. AT LOW LEVELS...A
SURFACE FRONT IS TO MEANDER ACROSS THE CENTRAL BAHAMAS INTO
CENTRAL/WESTERN CUBA WHILE TRAILING ACROSS THE GULF TO THE CENTRAL
STATES OF MEXICO. TRAILING END OF THE FRONT IS TO MEANDER NORTH
ACROSS VERACRUZ TO TAMAULIPAS LATER THIS EVENING...INTO TEXAS/RIO
BRAVO BASIN EARLY ON SATURDAY. PORTION OVER THE BAHAMAS-CUBA IS TO
GENERALLY REMAINS STATIONARY WHILE GRADUALLY WEAKENING THROUGH
SUNDAY EVENING. ALTHOUGH WEAKENING...IT IS TO CONTINUE ENHANCING
LOW LEVEL MOISTURE CONVERGENCE ACROSS CUBA AND THE BAHAMAS. OVER
THE BAHAMAS THIS IS TO FAVOR SCATTERED CONVECTION WITH
ACCUMULATION OF 00-05MM/DAY AND MAXIMA OF 10MM...WHILE OVER
CENTRAL/EASTERN CUBA IT IS TO FAVOR RAINFALL AMOUNTS OF
05-10MM/DAY AND MAXIMA OF 15MM.

A 250 HPA HIGH SOUTH OF GUERRERO/OAXACA MEXICO ANCHORS A RIDGE
ACROSS MEXICO-CENTRAL AMERICA. UPPER LEVEL RIDGE PATTERN IS TO
GENERALLY PERSIST OVER THE NEXT FEW DAYS. MEANWHILE...AS THE UPPER
RIDGE HOLDS...IT IS TO VENT DEEP CONVECTION IN ASSOCIATION WITH A
DISTURBANCE OFF THE SOUTHERN COAST OF MEXICO. THE NHC CONTINUES TO
MONITOR THIS FEATURE FOR POSSIBLE TROPICAL CYCLONE FORMATION...AND
THERE IS A HIGH LIKELIHOOD THAT A DEPRESSION MIGHT FORM LATER
TODAY. AS IT BECOMES BETTER ORGANIZED...THE SURFACE CYCLONE IS TO
ANCHOR THE ITCZ ALONG ITS CLIMATOLOGICAL POSITION ALONG THE SOUTH
COAST OF MEXICO-SOUTHERN GUATEMALA/EL SALVADOR TO WESTERN
NICARAGUA. OVER GUATEMALA-EL SALVADOR/EASTERN NICARAGUA THIS IS TO
ENHANCE CONVECTIVE DEVELOPMENT TO FAVOR RAINFALL AMOUNTS OF
10-15MM/DAY AND MAXIMA OF 20-35MM. ACROSS SOUTHERN
GUERRERO/CHIAPAS EXPECTING RAINFALL AMOUNTS OF 15-20MM/DAY AND
MAXIMA OF 25-50MM. THROUGH FRIDAY EVENING CONVECTION IS TO SPREAD
WEST ACROSS THE SOUTHERN TO SOUTHWEST COAST OF MEXICO...WITH
ONSHORE FLOW TO INTENSIFY THROUGH SATURDAY MORNING LEADING TO AN
INCREASE IN CONVECTION. IN THIS AREA EXPECTING RAINFALL AMOUNTS OF
25-50MM/DAY AND MAXIMA OF 75-150MM THROUGH SUNDAY. MOISTURE AND
CONVECTION IS TO THEN BUILD NORTH ACROSS CENTRAL TO NORTHEAST
STATES OF MEXICO...TO SUSTAIN RAINFALL AMOUNTS OF 15-30MM/DAY AND
MAXIMA OF 40-80MM.

DOWNSTREAM FROM THE UPPER LEVEL RIDGE...A TUTT LOW TO THE SOUTH OF
THE DOMINICAN REPUBLIC EXTENDS A TROUGH TO THE GULF OF
URABA/NORTHERN COLOMBIA. THE TROUGH IS PRESSING AGAINST A WANING
RIDGE TO THE EAST...AND THROUGH SATURDAY MORNING THE RIDGE IS
FORECAST TO COLLAPSE WHILE THE TROUGH SETTLES OVER THE EASTERN
CARIBBEAN/NORTHERN SOUTH AMERICA. AT MID LEVELS...SHORT WAVE RIDGE
EXTENDS ACROSS THE EASTERN CARIBBEAN...WHILE ANCHORING ON A CLOSED
HIGH OVER THE VIRGIN ISLES/PUERTO RICO. THE RIDGE IS TO GRADUALLY 
PHASE WITH THE SUBTROPICAL RIDGE AS IT SLOWLY BUILDS FROM THE WEST
ACROSS THE GREATER ANTILLES THROUGH SUNDAY EVENING/MONDAY MORNING.
AS THE MID LEVEL RIDGE HOLDS...IT IS TO SUSTAIN A TRADE WINDS CAP
ACROSS THE LESSER ANTILLES TO PUERTO RICO AND EASTERN PORTIONS OF
HISPANIOLA. AT LOW LEVELS LIGHT EASTERLY TRADES ARE EXPECTED TO
PREVAIL OVER THE NEXT FEW DAYS...WITH DIURNAL HEATING/NOCTURNAL
COOLING INDUCED BREEZES TO GENERALLY DOMINATE LOCAL CIRCULATION.
OVER THE LARGER ISLANDS THIS IS LIKELY TO FAVOR SOME CONVECTION
ACROSS THE HIGHER ELEVATIONS...BUT FOR THE MOST PART ONLY
EXPECTING RAINFALL AMOUNTS OF 00-05MM AND MAXIMA OF 10MM IN
ISOLATED CONVECTION. HIGHER AMOUNTS...HOWEVER...ARE EXPECTED
ACROSS CENTRAL HISPANIOLA...WHERE TUTT ALOFT IS TO ENHANCE
CONVECTIVE INSTABILITY. THROUGH SATURDAY THIS IS TO INCREASE TO
10-15MM/DAY AND MAXIMA OF 20-35MM.

SOUTHERN CENTRAL AMERICA AND NORTHERN SOUTH AMERICA ARE TO REMAIN
UNDER INFLUENCE OF THE ITCZ/NEAR EQUATORIAL TROUGH. ALONG THIS
AXIS...A CELL OF THE PANAMANIAN LOW IS TO SLOWLY ROLL TO THE WEST
FROM WESTERN COLOMBIA TO COSTA RICA/SOUTHERN NICARAGUA EARLY ON
SUNDAY. EARLY IN THE CYCLE THIS IS TO ENHANCE MOISTURE CONVERGENCE
ACROSS WESTERN-NORTHERN PORTIONS OF COLOMBIA/ NORTHWEST
VENEZUELA...TO FAVOR RAINFALL AMOUNTS OF 15-20MM/DAY AND MAXIMA OF
25-50MM. BUT AS THE LOW MOVES AWAY...THIS IS TO DECREASE TO
10-15MM/DAY AND MAXIMA OF 20-40MM. OVER PANAMA-COSTA RICA THE
OPPOSITE IS TO TAKE PLACE...WITH RELOCATING LOW TO GRADUALLY FAVOR
AN INCREASE IN CONVECTION ACROSS THE ISTHMUS. INITIALLY EXPECTING
RAINFALL AMOUNTS OF 10-15MM/DAY AND MAXIMA OF 20-35MM. THROUGH
SATURDAY EVENING/EARLY SUNDAY THIS IS TO INCREASE TO 15-20MM/DAY
AND MAXIMA OF 25-50MM.

A TUTT LOW NEAR 23N 50W EXTENDS A TROUGH TO THE SOUTH-SOUTHWEST TO
JUST NORTH OF THE GUIANAS. TUTT PATTERN IS TO REMAIN NEARLY
STATIONARY OVER THE NEXT COUPLE OF DAYS...BUT AS THE UPPER LEVEL
RIDGE OVER THE EASTERN CARIBBEAN COLLAPSES...THE TUTT IS FORECAST
TO SLOWLY LIFT TO THE NORTH-NORTHEAST LATER ON SUNDAY.
MEANWHILE...THIS IS TO ENHANCE COASTAL CONVECTION ACROSS THE
NORTHERN GUIANAS-NORTHEAST VENEZUELA. INITIALLY EXPECT RAINFALL
AMOUNTS OF 00-05MM/DAY AND MAXIMA OF 10MM. THROUGH SATURDAY THIS
INCREASES TO 05-10MM/DAY AND MAXIMA OF 15MM.

TROPICAL/EASTERLY WAVES INITIALIZED AT 12UTC
INITIAL  24     36     48     60     72     84     96     TYPE
29W      31W    34W    36W    39W    42W    45W    48W    TW

TROPICAL WAVE ALONG 29W IS TO CONFINE TO THE ATLANTIC ITCZ OVER
THE NEXT FEW DAYS.

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