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267
FXCA20 KWBC 211843
PMDCA

TROPICAL DISCUSSION - INTERNATIONAL DESKS
NWS WEATHER PREDICTION CENTER COLLEGE PARK MD
242 PM EDT TUE OCT 21 2014

DISCUSSION FROM OCTOBER 21/00UTC: AMPLIFYING POLAR TROUGH LIES
ACROSS THE EASTERN USA TO THE FLORIDA PENINSULA. THROUGH THURSDAY
EVENING THE TROUGH IS TO SLOWLY PULL TO THE EAST-NORTHEAST AS
ANOTHER TROUGH APPROACHES FROM THE WEST. AT LOW LEVELS...THIS IS
TO SUSTAIN A SURFACE FRONT ACROSS NORTHERN FLORIDA TO THE GULF OF
MEXICO EARLY IN THE CYCLE. THE FRONT IS TO REMAIN NEARLY
STATIONARY THROUGH 24HRS RAPIDLY WEAKENING. SOUTH OF THIS
AXIS...MODELS INITIALIZE A DISORGANIZED LOW PRESSURE SYSTEM OVER
THE CAMPECHE SOUND. THROUGH WEDNESDAY EVENING THE LOW IS TO DRIFT
TO THE NORTHERN YUCATAN...AND BY FIRST LIGHT ON FRIDAY IT IS TO
PULL ACROSS WESTERN CUBA. AS IT LIFTS TO THE NORTHEAST... THIS IS
TO GRADUALLY MERGE WITH A NEW SURFACE FRONT TO THE NORTH...DRAWING
THE BAROCLINIC BOUNDARY SOUTHWARD INTO THE NORTHEAST BAHAMAS. MOST
ACTIVE CONVECTION IS EXPECTED IN ASSOCIATION WITH THE SURFACE LOW
AS IT MEANDERS OVER THE SOUTHERN GULF TO THE YUCATAN/WESTERN CUBA.
ACROSS SOUTHERN VERACRUZ/CHIAPAS-TO SOUTHERN GUATEMALA THIS IS TO
SUSTAIN RAINFALL AMOUNTS OF 50-75XXMM/DAY AND ISOLATED MAXIMA OF
150-250MM THROUGH WEDNESDAY MORNING. NOTE THAT IN THIS AREA STRONG
TOPOGRAPHICAL FORCING IS LIKELY TO RESULT IN LOCALIZED MAXIMA IN
EXCESS OF FORECAST GUIDANCE. ACROSS NORTHERN VERACRUZ IT IS TO
SUSTAIN RAINFALL AMOUNTS OF 15-20MM/DAY AND MAXIMA OF 35-70MM. AS
THE LOW LIFTS ACROSS THE YUCATAN THIS IS TO THEN SUSTAIN RAINFALL
AMOUNTS OF 35-70MM/DAY AND MAXIMA OF 150-200MM ON WEDNESDAY TO
THURSDAY MORNING. AT IT INTERACTS WITH THE FRONT TO THE NORTH...
CONVECTION IS TO RAPIDLY EXPAND ACROSS THE YUCATAN CHANNEL TO
WESTERN CUBA/ISLA DE LA JUVENTUD...WHERE IT IS TO SUSTAIN RAINFALL
AMOUNTS OF 15-30MM/DAY AND MAXIMA OF 40-80MM BY WEDNESDAY INTO
THURSDAY...AND 35-70MM/DAY AND MAXIMA OF 150-200MM/DAY BY THURSDAY
INTO FRIDAY. LOW LEVEL WINDS ACROSS THE YUCATAN/WESTERN CARIBBEAN
ARE TO THEN SHIFT TO THE NORTH-NORTHWEST...RESULTING IN MOISTURE
CONVERGENCE ACROSS SOUTHERN PORTIONS OF BELIZE TO CENTRAL
GUATEMALA. IN THIS AREA EXPECTING SIMILAR RAINFALL AMOUNT. AS THE
SURFACE LOW MERGES WITH THE FRONT...CONVECTION IS TO THEN BUILD
ACROSS THE CENTRAL-NORTHWEST BAHAMAS...TO RESULT IN RAINFALL
AMOUNTS OF 15-20MM/DAY AND MAXIMA OF 30-60MM BY THURSDAY INTO
FRIDAY...WITH AN INCREASING TREND INTO SATURDAY.

FURTHERMORE...THE SURFACE LOW...AS IT MEANDERS OVER THE SOUTHERN
GULF...WILL SUSTAIN A SOUTHWESTERLY FLOW ACROSS THE SOUTHERN
STATES OF MEXICO TO CENTRAL AMERICA. THIS...IN-TURN...IS TO ANCHOR
THE EASTERN PACIFIC ITCZ ALONG THE COAST OF CENTRAL AMERICA INTO
SOUTHERN NICARAGUA/SOUTHERN CARIBBEAN. AT UPPER
LEVELS...PERSISTENT RIDGE IS TO DOMINATE THE UPPER FLOW...AS IT IS
TO EXTENDS WEST-TO-EAST ACROSS CENTRAL/SOUTHERN MEXICO TO THE
CARIBBEAN BASIN. AS THE RIDGE HOLDS...THIS IS TO VENT DEEP
CONVECTION ALONG THE CONVERGENCE ZONE. ACROSS GUATEMALA-EL
SALVADOR/SOUTHERN HONDURAS TO EASTERN NICARAGUA THIS IS TO FAVOR
RAINFALL AMOUNTS OF 05-10MM/DAY AND MAXIMA OF 15-20MM THROUGH 36
HRS...INCREASING TO 15-20MM/DAY AND MAXIMA OF 25-50MM BY WEDNESDAY
INTO THURSDAY...DECREASING SLIGHTLY AFTER. HIGHER AMOUNTS ARE
EXPECTED ALONG THE ITCZ OVER SOUTHERN NICARAGUA/WESTERN COSTA
RICA...WITH TOTALS OF 15-20MM/DAY AND MAXIMA OF 25-50MM THROUGH
EARLY WEDNESDAY...AND 05-10MM/DAY AND MAXIMA OF 15-20MM
THEREAFTER. ACROSS PANAMA...WITH THE ITCZ FAR TO THE NORTH OVER
THE SOUTHERN CARIBBEAN...DIURNAL CONVECTION IS TO SUSTAIN RAINFALL
AMOUNTS OF 05-10MM/DAY AND MAXIMA OF 15-20MM. MOST INTENSE IS
EXPECTED ALONG THE CONTINENTAL DIVIDE.

EAST OF THE UPPER LEVEL RIDGE...OVER THE CARIBBEAN...A TUTT
EXTENDS ACROSS HAITI TO JUST NORTH OF PANAMA. THIS IS INTERACTING
WITH THE NEAR EQUATORIAL TROUGH OVER NORTHERN COLOMBIA/NORTHWEST
VENEZUELA...FAVORING ORGANIZED DEEP CONVECTION. BUILDING RIDGE IS
TO DISPLACE THIS TROUGH EAST ACROSS PUERTO RICO TO THE LEEWARD
ISLES LATER THIS EVENING. THROUGH THURSDAY MORNING THE TROUGH
MIGRATES FARTHER EAST ACROSS THE WINDWARD ISLANDS TO NORTHERN
VENEZUELA...WHERE IT IS TO REMAIN THROUGH THE END OF THE WEEK
WHILE SLOWLY BECOMING BETTER ORGANIZED. EARLY IN THE CYCLE THIS IS
TO ENHANCE DEVELOPMENT ACROSS NORTHWEST VENEZUELA-NORTHERN
COLOMBIA...TO SUSTAIN RAINFALL AMOUNTS OF 15-20MM/DAY AND MAXIMA
OF 25-50MM. BUT AS THE TROUGH PULLS AWAY...AND DYNAMICAL FORCING
WANES EXPECTING RAINFALL AMOUNTS OF 05-10MM/DAY AND MAXIMA OF
15-20MM. THE TROUGH IS TO THEN ENHANCE CONVECTIVE DEVELOPMENT
ACROSS CENTRAL VENEZUELA...WHERE IT IS TO FAVOR RAINFALL AMOUNTS
OF 10-15MM/DAY AND MAXIMA OF 20-40MM. AS THE TROUGH PULLS ACROSS
PUERTO RICO IT IS TO FAVOR RAINFALL AMOUNTS OF 05-10MM/DAY AND
MAXIMA OF 15-25MM EARLY IN THE CYCLE. BUT AS THE TROUGH PULLS
AWAY...FAIR WEATHER CONDITIONS ARE TO GENERALLY PREVAIL AS AN
UPPER CONVERGENT PATTERN ESTABLISHES AND MOISTURE EBBS AWAY. OVER
THE FRENCH AND WINDWARD ISLES-ORINOCO DELTA/NORTHERN GUYANA...AS
IT INTERACTS WITH THE ATLANTIC ITCZ...IT IS TO THEN FAVOR RAINFALL
AMOUNTS INCREASING TO 15-20MM/DAY AND MAXIMA OF 25-50MM.

TROPICAL/EASTERLY WAVES INITIALIZED AT 12UTC
INITIAL  24     36     48     60     72     84     96     TYPE
36W     38W    39W    41W    43W    45W    47W    49W     TW
54W     56W    58W    60W    62W    64W    66W    68W     TW

TROPICAL WAVE ALONG 36W REACHES FRENCH GUIANA LATER ON FRIDAY...TO
FAVOR ENHANCED CONVECTION.

TROPICAL WAVE ALONG 54W SUSTAINS ORGANIZED DEEP CONVECTION ALONG
THE ATLANTIC ITCZ. ACTIVITY IS TO BUILD WESTWARD SLOWLY INTO
NORTHERN GUYANA/NORTHEAST VENEZUELA THROUGH THE EVENING HOURS...TO
RESULT IN RAINFALL AMOUNTS OF 10-15MM/DAY AND MAXIMA OF 20-35MM.
OVER THE WINDWARD ISLES THIS IS TO THEN INTERACT WITH AMPLIFYING
TUTT OVER THE EASTERN CARIBBEAN...TO RESULT IN RAINFALL AMOUNTS OF
15-20MM/DAY AND MAXIMA OF 25-50MM. OVER EASTERN-CENTRAL
VENEZUELA...IN INTERACTION WITH THE EQUATORIAL TROUGH...EXPECTING
RAINFALL SIMILAR AMOUNTS.

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

$$






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