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Tropical Discussion
 
(Caution: Version displayed is not the latest version. - Issued 1830Z Aug 18, 2014)
 
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TROPICAL DISCUSSION - INTERNATIONAL DESKS
NWS WEATHER PREDICTION CENTER COLLEGE PARK MD
230 PM EDT MON AUG 18 2014

DISCUSSION FROM AUGUST 18/00UTC: WEST OVER THE DOMAIN...AT 250
HPA...A CLOSED HIGH SOUTH OF THE BAJA PENINSULA EXTENDS A RIDGE
NORTH ACROSS NORTHWEST MEXICO TO THE WESTERN USA. THROUGH TUESDAY
EVENING THE HIGH LIFT ACROSS SINALOA TO SOUTHERN SONORA...WHERE IT
IS TO REMAIN THROUGH THURSDAY MORNING. THE RIDGE ALOFT IS TO VENT
DIURNAL CONVECTION ALONG THE SIERRA MADRE OCCIDENTAL...WITH
RAINFALL AMOUNTS OF 15-20MM/DAY AND MAXIMA OF 25-50MM. THROUGH
WEDNESDAY THIS DECREASES TO 10-15MM/DAY AND MAXIMA OF 20-35MM.

A TUTT LOW LIES TO THE EAST OF THIS RIDGE...CENTERING OVER THE
WESTERN GULF JUST EAST OF TAMAULIPAS MEXICO. THE LOW EXTENDS A
TROUGH SOUTH ACROSS THE CENTRAL STATES OF MEXICO. THIS PATTERN IS
FORECAST TO PERSIST DURING THE NEXT FEW DAYS. MEANWHILE...IT IS TO
INTERACT WITH SEA BREEZE CONVERGENCE/ DIURNAL HEATING IN SUPPORT
OF MODERATE TO HEAVY CONVECTION. ACROSS TAMAULIPAS-VERACRUZ-SAN
LUIS POTOSI THIS IS TO SUSTAIN RAINFALL AMOUNTS OF 05-10MM/DAY AND
MAXIMA OF 15-25MM. THROUGH WEDNESDAY THIS INCREASES TO 15-20MM/DAY
AND MAXIMA OF 25-50MM. ACROSS MEXICO/MEXICO
DF-MICHOACAN/NAYARIT-GUERRERO EXPECTING ACCUMULATION OF
15-20MM/DAY AND MAXIMA OF 30-60MM THROUGH TUESDAY MORNING.
THEREAFTER...EXPECTING MAXIMA OF 25-50MM/DAY.

THE SOUTHERN STATES OF MEXICO AND CENTRAL AMERICA ARE UNDER THE
INFLUENCE OF AN UPPER LEVEL RIDGE THAT CENTERS ON A CLOSED HIGH
OVER GUATEMALA. SHORT WAVE RIDGE PATTERN HOLDS THROUGH TUESDAY
EVENING...THEN WEAKENS THROUGH THE DAY ON WEDNESDAY AS TUTT LOW
OVER THE WESTERN CARIBBEAN RETROGRESSES TO THE GULF OF HONDURAS.
THE RIDGE ALOFT IS TO VENT DEEP CONVECTION ACROSS GUATEMALA-EL
SALVADOR/HONDURAS. ALONG THE CONTINENTAL DIVIDE EXPECTING
ACCUMULATION OF 10-15MM/DAY AND MAXIMA OF 20-35MM. TO THE NORTH
EXPECT ACCUMULATION OF 05-10MM/DAY AND MAXIMA OF 15-20MM. ON THE
SOUTHERN STATES OF MEXICO EXPECTING RAINFALL AMOUNTS OF
10-15MM/DAY AND MAXIMA OF 20-35MM/DAY.

THE WESTERN CARIBBEAN TUTT CENTERS ON A CLOSED LOW NEAR THE CAYMAN
ISLANDS. THIS LOW EXTENDS A SHORT WAVE TROUGH SOUTH TO BOCAS DEL
TORO IN WESTERN PANAMA. THROUGH WEDNESDAY EVENING THE TUTT LOW
MEANDERS WEST TO THE GULF OF HONDURAS...WITH SHORT WAVE TROUGH
INTO HONDURAS. EARLY IN THE CYCLE THIS IS TO INTERACT WITH THE
ITCZ OVER SOUTHERN NICARAGUA-COSTA RICA AND PANAMA...TO FAVOR
RAINFALL AMOUNTS OF 15-20MM/DAY AND MAXIMA OF 30-60MM. BUT AS THE
TROUGH PULLS AWAY...THIS WILL DECREASE TO 10-15MM/DAY AND MAXIMA
OF 20-45MM. THE TROUGH IS TO ALSO ENHANCE CONVECTIVE DEVELOPMENT
ACROSS THE CAYMAN ISLES...WHERE WE EXPECT ACCUMULATION OF
05-10MM/DAY AND MAXIMA OF 15MM.

AT MID LEVELS...A RIDGE EXTENDS EAST-TO-WEST ACROSS THE ATLANTIC
ALONG 25N/30N TO THE GULF OF MEXICO. A CLOSED HIGH OVER SOUTH
FLORIDA IS TO ANCHOR THIS AXIS EARLY IN THE CYCLE. AMPLIFYING
POLAR TROUGH OVER THE EASTERN USA IS TO THEN SPLIT THIS RIDGE IN
TWO CELLS LATER ON WEDNESDAY...WITH ONE TO CONFINE TO THE GULF OF
MEXICO/SOUTHEAST USA AND THE OTHER TO THE CENTRAL ATLANTIC. ACROSS
THE BAHAMAS THIS IS TO THEN SUSTAIN AN INDUCED/INVERTED
TROUGH...TO ENHANCE MOISTURE CONVERGENCE ACROSS THE NORTHWEST
ISLANDS TO RESULT IN RAINFALL AMOUNTS OF 05-10MM/DAY AND MAXIMA OF
15MM.

EVOLVING MID/UPPER LEVEL RIDGE PATTERN WILL ALLOW A TUTT LOW OVER
THE ATLANTIC TO RETROGRESS TOWARDS THE BASIN. THE TUTT LOW MOVES
TO THE NORTHERN LEEWARD ISLES BY MIDDAY ON TUESDAY...AND NORTH OF
PUERTO RICO/VI EARLY ON WEDNESDAY. THIS IS TO EXTEND A SHORT WAVE
TROUGH INTO THE EASTERN CARIBBEAN. BUILDING RIDGE IS TO THEN
DISPLACE THIS TROUGH/LOW FARTHER TO THE WEST. AS IT MEANDERS
ACROSS THE FORECAST AREA...THIS IS TO REFLECT QUITE WELL AT
LOW-MID LEVELS OF THE ATMOSPHERE...ENHANCING LOW LEVEL MOISTURE
CONVERGENCE WHILE FAVORING CONVECTIVE INSTABILITY. OVER THE LESSER
ANTILLES THIS IS TO FAVOR RAINFALL AMOUNTS OF 00-05MM/DAY AND
MAXIMA OF 10MM. ACROSS THE VIRGIN ISLES-PUERTO RICO AND THE
DOMINICAN REPUBLIC THE MOST ACTIVE IS EXPECTED ON WEDNESDAY...WHEN
IT IS TO FAVOR RAINFALL AMOUNTS OF 10-15MM/DAY AND MAXIMA OF
20-35MM. OVER GUYANA-NORTHEAST VENEZUELA...IN INTERACTION WITH THE
ATLANTIC ITCZ...THIS IS TO FAVOR RAINFALL AMOUNTS OF 05-10MM/DAY
AND MAXIMA OF 15-20MM. THROUGH WEDNESDAY EVENING THIS IS TO SHIFT
ACROSS CENTRAL-NORTHWEST VENEZUELA/NORTHERN COLOMBIA...WITH
RAINFALL AMOUNTS OF 10-15MM/DAY AND MAXIMA OF 20-35MM.

TROPICAL/EASTERLY WAVES INITIALIZED AT 12UTC
INITIAL  24     36     48     60     72     84     96     TYPE
32W      37W    41W    44W    47W    51W    55W    59W     TW
40W      43W    47W    52W    56W    60W    64W    68W     TW
79W      82W    85W    87W    90W    93W    95W    97W     TW

AT 700 HPA...A TROPICAL WAVE ALONG 32W IS TO REACH FRENCH GUIANA
LATER ON WEDNESDAY...THEN QUICKLY MOVE ACROSS SURINAME TO GUYANA
THROUGH THURSDAY AFTERNOON. ACROSS THE GUIANAS IT IS TO FAVOR
RAINFALL AMOUNTS OF 05-10MM/DAY AND MAXIMA OF 15-20MM.

A STRONGER WAVE LIES TO THE WEST...WITH AXIS ALONG 40W. THIS
REACHES FRENCH GUIANA LATER ON TUESDAY...PULLING ACROSS
SURINAME/GUYANA TO THE EASTERN CARIBBEAN ISLES DURING THE DAY ON
WEDNESDAY. THIS IS TO SUSTAIN SCATTERED CONVECTION WITH
ACCUMULATION OF 05-10MM/DAY AND MAXIMA OF 15-20MM. OVER THE LESSER
ANTILLES AND NORTHEAST VENEZUELA IT IS TO ALSO FAVOR RAINFALL
AMOUNTS OF 05-10MM/DAY AND MAXIMA OF 15-20MM. ACROSS
EASTERN-CENTRAL VENEZUELA THEN EXPECT ACCUMULATION OF 10-15MM/DAY
AND MAXIMA OF 20-40MM...WHILE OVER PUERTO RICO EXPECTING
ACCUMULATION OF 10-15MM/DAY AND MAXIMA OF 20-35MM.

TROPICAL WAVE ALONG 79W IS TO SURGE ACROSS THE CARIBBEAN/CENTRAL
AMERICA. ACROSS COSTA RICA TO NICARAGUA IT IS TO SUSTAIN RAINFALL
AMOUNTS OF 15-20MM/DAY AND MAXIMA OF 30-60MM THROUGH TUESDAY
MORNING...WHILE OVER HONDURAS-EL SALVADOR EXPECTING ACCUMULATION
OF 10-15MM/DAY AND MAXIMA OF 20-35MM DURING THE DAY ON TUESDAY.
OVER GUATEMALA-SOUTHERN MEXICO IT IS TO THEN TRIGGER RAINFALL
AMOUNTS OF 10-15MM/DAY AND MAXIMA OF 20-45MM ON WEDNESDAY. ACROSS
SOUTHERN MEXICO EXPECT ACCUMULATION OF 15-20MM/DAY AND MAXIMA OF
30-60MM.

VALVERDE...IMN (COSTA RICA)
MEDINA...ONAMET (REPUBLICA DOMINICANA)
DAVISON...WPC(USA)