Prognostic Meteorological Discussion
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FXCA20 KWBC 301825
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TROPICAL DISCUSSION - INTERNATIONAL DESKS
NWS WEATHER PREDICTION CENTER COLLEGE PARK MD
225 PM EDT TUE JUN 30 2015

DISCUSSION FROM JUNE 30/12 UTC: PERSISTENT MID/UPPER LEVEL RIDGE
REMAINS THE DOMINANT FEATURE OVER THE WESTERN USA. A
NARROW/ELONGATED TROUGH ALONG THE MEXICO/USA BORDER SEPARATES THE
LATTER FROM ANOTHER RIDGE OVER MEXICO/NORTHERN CENTRAL AMERICA.
UNDER INFLUENCE OF THE RIDGE TO THE NORTH...SHORT WAVE VORTICES
ARE TO DIVE ACROSS THE GULF...WITH MODELS SHOWING GRADUAL
INTENSIFICATION OF UPPER TROUGH PATTERN THROUGH THURSDAY EVENING.
LATER IN THE CYCLE AT TUTT LOW IS TO CLOSE OFF THE WEST COAST OF
CUBA...WHILE TROUGH PATTERN SHIFTS TO THE CENTRAL STATES OF
MEXICO. AT MID LEVELS THIS IS TO FAVOR A SHORT WAVE TROUGH ACROSS
NORTHEAST TO CENTRAL MEXICO EARLY IN THIS PERIOD...WITH AXIS TO
BECOME BETTER ORGANIZED THROUGH WEDNESDAY EVENING. THROUGH
THURSDAY EVENING THE TROUGH IS TO SHIFT SOUTH ACROSS CENTRAL TO
SOUTHERN MEXICO AS THE RIDGE BUILDS TO THE NORTH. INFLOW OF SHORT
WAVE ENERGY ALOFT WILL COMBINE WITH THERMAL TROUGH OVER MEXICO TO
SUSTAIN DEEP LAYER CONVECTIVE INSTABILITY. OVER NORTHEAST MEXICO
THIS IS TO FAVOR RAINFALL AMOUNTS OF 15-20MM/DAY AND MAXIMA OF
35-70MM. THROUGH THURSDAY EVENING THIS DECREASES TO 05-10MM/DAY
AND MAXIMA OF 15-25MM. OVER CENTRAL-SOUTHERN MEXICO INITIALLY
EXPECTING RAINFALL AMOUNTS OF 05-10MM/DAY AND MAXIMA OF 15-25MM.
THROUGH THURSDAY MOST INTENSE IS TO DEVELOP OVER CENTRAL AND
SOUTHWEST MEXICO...WHERE WE EXPECT RAINFALL AMOUNTS OF 15-20MM/DAY
AND MAXIMA OF 30-60MM. OVER SONORA-SINALOA TO THE
WEST...MEANWHILE...EXPECTING RAINFALL AMOUNTS OF 10-15MM/DAY AND
MAXIMA OF 20-35MM IN SCATTERED CONVECTION. SLIGHTLY HIGHER AMOUNTS
ARE POSSIBLE ON THURSDAY.

A BROAD CELL OF THE SUBTROPICAL RIDGE LIES TO THE EAST...WITH MID
LEVEL CIRCULATION OVER THE CENTRAL ATLANTIC TO EXTEND A RIDGE TO
THE WEST-SOUTHWEST INTO THE GULF OF MEXICO. ON THE SOUTHERN STATES
OF MEXICO/THE YUCATAN-NORTHERN CENTRAL AMERICA THE PERSISTENT
RIDGE ALOFT IS TO SUSTAIN A CAP INVERSION...AND THIS IS TO INHIBIT
ORGANIZED CONVECTION. IN THIS PATTERN DIURNAL CONVECTION IS TO
GENERALLY LIMIT TO THE CONTINENTAL DIVIDE...WHERE WE EXPECT
ISOLATED TO SCATTERED CONVECTION TO SUSTAIN RAINFALL AMOUNTS OF
05-10MM/DAY AND MAXIMA OF 15-25MM. HOWEVER...A LULL IN ACTIVITY IS
EXPECTED ON WEDNESDAY...WHEN RAINFALL AMOUNTS DECREASE TO
00-05MM/DAY AND MAXIMA OF 10MM. ACROSS SOUTHERN CENTRAL AMERICA
THE ENVIRONMENTAL CONDITIONS REMAIN MORE FAVORABLE. UNDER
INFLUENCE OF THE EASTERN PACIFIC ITCZ EXPECTING SCATTERED
CONVECTION ACROSS SOUTHERN NICARAGUA-COSTA RICA-PANAMA...TO
SUSTAIN RAINFALL AMOUNTS OF 10-15MM/DAY AND MAXIMA OF 20-40MM.
THIS DECREASES TO 05-10MM/DAY AND MAXIMA OF 15-25MM LATER ON
THURSDAY AS A DRYER AIR MASS ADVECTS ACROSS THE CENTRAL/SOUTHERN
CARIBBEAN.

FARTHER EAST...THE FLOW SPLITS BETWEEN A TUTT OVER THE NORTHEAST
CARIBBEAN ISLES AND THE SUBEQUATORIAL RIDGE TO THE SOUTH. TUTT
ALOFT SUSTAINS AN INVERTED TROUGH IN THE MID LEVEL EASTERLIES.
THIS MOVES ACROSS PUERTO RICO TO THE DOMINICAN REPUBLIC LATER THIS
AFTERNOON...AND INTO HAITI-SOUTHEAST BAHAMAS LATER ON WEDNESDAY.
THIS IS TO THEN REMAIN NEARLY STATIONARY WHILE GRADUALLY
WEAKENING. AS IT PULLS ACROSS PUERTO RICO TO THE DOMINICAN
REPUBLIC THIS IS TO ENHANCE CONVECTIVE INSTABILITY ACROSS THE
NORTHEAST CARIBBEAN ISLES. ACROSS PUERTO RICO-HISPANIOLA THIS IS
TO FAVOR RAINFALL AMOUNTS OF 05-10MM/DAY AND MAXIMA OF 15-25MM.
OVER THE SOUTHEAST BAHAMAS-EASTERN CUBA AND JAMAICA IT IS TO THEN
FAVOR RAINFALL AMOUNTS OF 00-05MM/DAY AND MAXIMA OF 10MM.

TROPICAL/EASTERLY WAVES INITIALIZED AT 12UTC
INITIAL  24     36     48     60     72     84     96        TYPE
32W      37W    42W    47W    52W    57W    62W    67W       TW
60W      67W    72W    77W    82W    86W    90W    93W   TUTT
INDUCED
76W      80W    83W    86W    90W    93W    96W    99W       TW
91W      93W    96W   100W   103W   106W   109W   112W       TW

TROPICAL WAVE ALONG 32W IS TO REACH THE GUIANAS EARLY ON THURSDAY
MORNING. AS IT NEARS FRENCH GUIANA IT IS TO INDUCE THE SOUTHWARD
MODULATION OF THE ITCZ ACROSS NORTHERN SURINAME TO NORTHERN
GUYANA. THIS IS TO ENHANCE LOW LEVEL MOISTURE CONVERGENCE TO FAVOR
RAINFALL AMOUNTS OF 10-15MM/DAY AND MAXIMA OF 20-35MM. BUT AS THE
WAVE MOVES WEST AND THE ITCZ MEANDERS NORTH THIS IS TO DECREASE TO
00-05MM/DAY AND MAXIMA OF 10MM. THE WAVE ENTERS THE ISLAND CHAIN
ON FRIDAY MORNING...WITH CONVECTION OVER THE SOUTHERN WINDWARD
ISLES/NORTHEAST VENEZUELA TO RESULT IN RAINFALL AMOUNTS OF
05-10MM/DAY AND MAXIMA OF 15-25MM...WHILE OVER THE NORTHERN
WINDWARD/FRENCH ISLES EXPECTING ACCUMULATION OF 00-05MM/DAY AND
MAXIMA OF 10MM.

THE EASTERN CARIBBEAN TUTT SUSTAINS AN INDUCED PERTURBATION IN THE
EASTERLY TRADES ALONG 60W EARLY THIS MORNING. THIS IS DRAWING THE
ITCZ NORTH ACROSS THE WINDWARD ISLES...WHERE IT IS ENHANCING
MOISTURE CONVERGENCE. IN THIS AREA EXPECTING SCATTERED CONVECTION
TO SUSTAIN RAINFALL AMOUNTS OF 10-15MM/DAY AND MAXIMA OF 20-35MM.
ACROSS VENEZUELA...IN INTERACTION WITH THE NEAR EQUATORIAL
TROUGH...THIS IS TO RESULT IN RAINFALL AMOUNTS OF 05-10MM/DAY AND
MAXIMA OF 15-25MM. THE WAVE TENDS TO WEAKEN ON THURSDAY TO
FRIDAY...AS A RESULT IT IS TO ONLY FAVOR SCATTERED CONVECTION
ACROSS COLOMBIA-SOUTHERN CENTRAL AMERICA. OVER COLOMBIA-PANAMA
EXPECTING RAINFALL AMOUNTS OF 05-10MM/DAY AND MAXIMA OF 15-25MM.

TROPICAL WAVE ALONG 76W PULLS ACROSS COLOMBIA TO PANAMA EARLY IN
THE CYCLE...TO SUSTAIN RAINFALL AMOUNTS OF 10-15MM/DAY AND MAXIMA
OF 20-40MM. ACROSS WESTERN PANAMA TO COSTA RICA AND SOUTHERN
NICARAGUA IT IS TO ALSO FAVOR RAINFALL ACCUMULATION OF 10-15MM/DAY
AND MAXIMA OF 20-35MM ON TUESDAY TO WEDNESDAY. ACROSS NORTHEAST
NICARAGUA EXPECT ACCUMULATION OF 00-05MM/DAY AND MAXIMA OF 10MM.
AFTERWARDS...MOST ACTIVE CONVECTION WITH THIS FEATURE IS EXPECTED
ALONG THE EASTERN PACIFIC ITCZ.

TROPICAL WAVE ALONG 91W IS TO FAVOR ISOLATED TO SCATTERED
CONVECTION ACROSS SOUTHERN GUATEMALA INTO CHIAPAS IN SOUTHERN
MEXICO EARLY IN THE CYCLE...WITH ACCUMULATION OF 05-10MM/DAY AND
MAXIMA OF 15-25MM. AFTERWARDS...MOST ACTIVE CONVECTION WITH THIS
FEATURE IS EXPECTED ALONG THE EASTERN PACIFIC ITCZ.

SALMON...MS (ANTIGUA AND BARBUDA)
SAMUEL...MDS (SURINAME)
DAVISON...WPC (USA)
$$




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