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The Weather Prediction Center
 
Tropical Discussion
 
(Latest Discussion - Issued 1916Z Nov 09, 2018)
 
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TROPICAL DISCUSSION - INTERNATIONAL DESKS
NWS WEATHER PREDICTION CENTER COLLEGE PARK MD
216 PM EST FRI NOV 09 2018

TROPICAL DISCUSSION FROM NOV 09/12 UTC: BROAD MID/UPPER LEVEL
TROUGH CONTINUES TO DOMINATE THE FLOW ACROSS NORTH AMERICA...WITH
AXIS EXPANDING INTO THE WESTERN ATLANTIC LATER ON SATURDAY. EARLY
NEXT WEEK...A STRONG SHORT WAVE TROUGH IS TO ROUND THE BASE OF THE
LONG WAVE AXIS...FAVORING THE SOUTHWARD AMPLIFICATION OF THE LONG
WAVE AXIS ACROSS THE WESTERN/CENTRAL USA TO THE NORTHERN STATES OF
MEXICO. AT LOW LEVELS...UNDER THE INFLUENCE OF A BUILDING POLAR
RIDGE...SURFACE FRONT SURGES ACROSS THE RIO BRAVO TO NORTHEAST
MEXICO EARLY IN THE CYCLE. DURING THE DAY ON SATURDAY IT THEN
SURGES ACROSS FLORIDA WHILE TRAILING ACROSS THE NORTHERN GULF TO
NORTHEAST MEXICO. AS IT SURGES ACROSS FLORIDA THIS IS TO THEN
INDUCE A PREFRONTAL SHEAR LINE ACROSS THE SOUTHEAST BAHAMAS/TURKS
AND CAICOS TO EASTERN CUBA LATER ON SATURDAY EVENING. THIS IS TO
THEN PERSIST THROUGH SUNDAY EVENING/EARLY MONDAY MORNING. FRONTAL
CONVECTION OVER TAMAULIPAS IN NORTHEAST MEXICO IS TO RESULT IN
RAINFALL AMOUNTS OF 10-15MM/DAY AND MAXIMA OF 20-35MM. ON SATURDAY
EXPECTING ADDITIONAL RAINFALL AMOUNTS OF 00-05MM/DAY AND MAXIMA OF
10MM AS THE FRONT RETROGRESSES ACROSS THE RIO BRAVO. EARLY NEXT
WEEK...THE FRONT SURGES AGAIN ACROSS NORTHEAST MEXICO...TO TRIGGER
HEAVY RAINFALL AMOUNTS ACROSS VERACRUZ TO NORTHERN CHIAPAS IN 
SOUTHERN MEXICO. IN THIS AREA...STORM TOTAL AMOUNTS ARE TO RANGE
BETWEEN 200-350MM. OVER THE BAHAMAS-CENTRAL CUBA...BRISK
NORTHEASTERLY WINDS ON SATURDAY-SUNDAY ARE TO FAVOR A COOL
ADVECTIVE PATTERN WHILE TRIGGERING LIGHT RAIN SHOWERS. MEASURABLE
RAINFALL AMOUNTS WILL LIMIT TO THE SHEAR LINE AS IT MOVES OVER THE
SOUTHEAST BAHAMAS/TURKS-EASTERN CUBA ON
SATURDAY-SUNDAY...TRIGGERING RAINFALL ACCUMULATION OF 00-05MM/DAY
AND MAXIMA OF 10MM.

SOUTH OF THE POLAR TROUGH...AT 500 HPA...A HIGH OVER THE YUCATAN
ANCHORS A CELL OF THE SUBTROPICAL RIDGE TO THE SOUTH. THE RIDGE
EXTENDS FROM CENTRAL/SOUTHERN MEXICO EASTWARD ACROSS
CUBA/NORTHWEST CARIBBEAN TO JAMAICA/HISPANIOLA. OVER THE NEXT
COUPLE OF DAYS THE MODELS CONTINUE TO FORESEE THE EASTWARD
EXPANSION OF THIS RIDGE ACROSS THE GREATER ANTILLES TO THE
NORTHEAST CARIBBEAN. EARLY NEXT WEEK...AS POLAR TROUGH PATTERN
OVER THE WESTERN USA/NORTHERN MEXICO DEEPENS... THE RIDGE WILL
START TO WEAKEN FROM THE WEST. MEANWHILE... THIS IS TO SUSTAIN A
TRADE WINDS CAP ACROSS THE SOUTHERN STATES OF MEXICO-CENTRAL
AMERICA-CUBA-JAMAICA-HISPANIOLA...TO BUILD ACROSS PUERTO
RICO/VIRGIN ISLES DURING THE WEEKEND. OVER SOUTHERN
MEXICO-NORTHERN CENTRAL AMERICA DIURNAL CONVECTIVE ACTIVITY WILL
LIMIT TO THE CONTINENTAL DIVIDE...GENERALLY FAVORING LIGHT
RAINFALL AMOUNTS DURING THE NEXT FEW DAYS...TO SUSTAIN
ACCUMULATION OF 00-05MM/DAY AND ISOLATED MAXIMA OF 10MM. HIGHER
AMOUNTS ARE EXPECTED OVER EASTERN NICARAGUA...WHERE UNDER
INFLUENCE OF TRADE WIND CONVERGENCE EXPECTING RAINFALL AMOUNTS OF
05-10MM/DAY AND MAXIMA OF 15-25MM. ON SUNDAY...AS THE TRADES
INCREASE TO 20-30KT WHILE BACKING TO THE NORTHEAST...THIS WILL
INCREASE TO 10-15MM/DAY AND MAXIMA OF 20-40MM.

A WANING TUTT TO THE NORTH-NORTHEAST OF PUERTO RICO IS EXPECTED TO
LIFT TO THE NORTHEAST AS A SECONDARY TROUGH STREAMING ACROSS THE
BAHAMAS APPROACHES FROM THE WEST. THE SHORT WAVE TROUGH MOVES
NORTH OF HISPANIOLA EARLY IN THE CYCLE...INTO PUERTO RICO DURING
THE DAY ON SATURDAY. IT THEN STALLS OVER THE NORTHEAST
CARIBBEAN...WHERE IT REMAINS THROUGH THE WEEKEND TO EARLY NEXT
WEEK. ACROSS PUERTO RICO INITIALLY EXPECTING RAINFALL AMOUNTS OF
05-10MM/DAY AND MAXIMA OF 15-25MM. ON SATURDAY THIS INCREASES TO
10-15MM/DAY AND MAXIMA OF 20-35MM/DAY AS ENHANCED BY THE UPPER
LEVEL TROUGH. FURTHERMORE...AT LOW LEVELS THIS IS INDUCING AN
INVERTED TROUGH OVER THE EASTERN CARIBBEAN TO THE WESTERN
ATLANTIC. THIS IS DRAWING THE ITCZ NORTH OF ITS CLIMATOLOGICAL
POSITION INTO THE WINDWARD/SOUTHERN FRENCH ISLES. THE ITCZ WILL
REMAIN NORTH OF ITS CLIMATOLOGICAL POSITION DURING THE NEXT FEW
DAYS. THIS WILL ENHANCE MOISTURE TRANSPORT/CONVERGENCE ACROSS THE
ISLAND CHAIN. OVER THE LEEWARD/FRENCH ISLES EXPECTING RAINFALL
AMOUNTS OF 15-20MM/DAY AND MAXIMA OF 25-50MM. ON SATURDAY...AS THE
TROUGH DEEPENS...THIS INCREASES TO MAXIMA OF 30-60MM. ON SUNDAY IT
STARTS TO WANE...DECREASING TO 10-15MM/DAY AND MAXIMA OF 20-40MM.
AS DEEPER MOISTURE ADVECTS ACROSS THE EASTERN CARIBBEAN/NORTHERN
VENEZUELA-ABC ISLES THIS WILL FEED DIURNAL CONVECTION...TO FAVOR
RAINFALL AMOUNTS OF 00-05MM/DAY AND MAXIMA OF 10MM/DAY IN ISOLATED
TO SCATTERED CONVECTION.

A CELL OF THE SUBEQUATORIAL RIDGE TO THE EAST EXTENDS FROM THE
TROPICAL ATLANTIC TO NORTHERN SOUTH AMERICA. THIS...HOWEVER...IS
FORECAST TO GRADUALLY WEAKEN LATER DURING THE WEEKEND.
MEANWHILE...THE RIDGE ALOFT IS TO VENT DEEP CONVECTION. ACROSS
CENTRAL/SOUTHERN VENEZUELA TO EASTERN COLOMBIA INITIALLY EXPECTING
RAINFALL AMOUNTS OF 10-15MM/DAY AND MAXIMA OF 20-35MM. ON
SATURDAY-SUNDAY IT DECREASES TO 05-10MM/DAY AND MAXIMA OF 15-20MM.
OVER AMAZONIA IN SOUTHERN COLOMBIA EXPECTING RAINFALL AMOUNTS OF
10-15MM/DAY AND MAXIMA OF 20-40MM...DECREASING TO 10-15MM/DAY AND
MAXIMA OF 20-30MM ON SUNDAY. ALONG THE WESTERN PLAINS OF
COLOMBIA/ANDEAN REGION EXPECTING RAINFALL AMOUNTS OF 10-15MM/DAY
AND MAXIMA OF 20-45MM. THIS DECREASES TO 05-10MM/DAY AND MAXIMA OF
15-25MM ON SUNDAY...EXCEPT FOR THE EJE CAFETERO TO THE
NORTHWEST...WHERE DAILY MAXIMA PEAKS AT 20-30MM.

TROPICAL/EASTERLY WAVES/TRADE WIND SURGES FROM 00 UTC:
INITIAL 24    36    48    60    72    84    96    TYPE     SOF
NONE

SERNA...IDEAM (COLOMBIA)
TEJADA...AAC (PANAMA)
DAVISON/GALVEZ...WPC (USA)