Prognostic Meteorological Discussion
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FXCA20 KWBC 071819
PMDCA

TROPICAL DISCUSSION - INTERNATIONAL DESKS
NWS WEATHER PREDICTION CENTER COLLEGE PARK MD
218 PM EDT TUE JUL 07 2015

DISCUSSION FROM JUL 07/12 UTC: CONSISTENT WITH PREVIOUS FORECAST A
MID/UPPER LEVEL RIDGE EXTENDS TO THE NORTHEAST ACROSS THE NORTHERN
STATES OF MEXICO TO THE CENTRAL PLAINS IN THE USA. AT 250 HPA THIS
RIDGE ANCHORS ON TWO CLOSED HIGHS...ONE OVER THE BAJA PENINSULA
AND THE OTHER OVER TENNESSEE. AT 500 HPA IT ANCHORS ON A
MEANDERING HIGH OVER CHIHUAHUA-SONORA IN NORTHWEST MEXICO. AS THE
UPPER RIDGE HOLDS...IT IS TO VENT DIURNAL CONVECTION ALONG THE
SIERRA MADRE OCCIDENTAL AND DEL SUR...WHERE WE EXPECT RAINFALL
AMOUNTS OF 10-15MM/DAY AND MAXIMA OF 20-45MM THROUGH THURSDAY
MORNING...AND 10-15MM/DAY AND MAXIMA OF 20-30MM ON THURSDAY TO
FRIDAY.

A TUTT TO THE EAST ANCHORS ON A CLOSED LOW OVER THE CENTRAL GULF
OF MEXICO...WITH TROUGH SOUTH ACROSS THE SOUTHERN STATES OF MEXICO
TO THE EASTERN TROPICAL PACIFIC. UNDER INFLUENCE OF THE RIDGE TO
THE WEST...A JET MAXIMA ENTERED THE BACKSIDE OF THIS TROUGH.
THIS...IN-TURN...WILL INDUCE THE SOUTHWARD AMPLIFICATION AND
GRADUAL INTENSIFICATION OF THE TROUGH ACROSS SOUTHERN MEXICO. A
LOW IS TO THEN CLOSE OVER CENTRAL MEXICO LATER ON
WEDNESDAY...FORECAST TO RELOCATE SOUTH OF COLIMA/NAYARIT ON
THURSDAY. AT 500 HPA IT IS TO INITIALLY REFLECT AS AN INVERTED
TROUGH OVER THE WESTERN GULF OF MEXICO. THROUGH WEDNESDAY EVENING
THIS IS TO ALSO DEEPEN/BECOME BETTER ORGANIZED...WITH LOW ALONG
THIS AXIS EXPECTED TO CLOSE JUST SOUTH OF GUERRERO. DEEPENING
MID/UPPER LEVEL TROUGH PATTERN IS TO FAVORABLY INTERACT WITH THE
EASTERN PACIFIC ITCZ...SUSTAINING THE NORTHWARD MODULATION OF THE
CONVERGENCE ZONE ALONG THE COAST OF CENTRAL AMERICA WHILE
TRIGGERING A CLOSED LOW. FURTHER INTERACTION WITH A TROPICAL WAVE
WILL LIKELY FAVOR RAPID INTENSIFICATION OF THIS CIRCULATION LATER
IN THE CYCLE. AS THE MID/UPPER TROUGH DEEPENS THIS IS TO ENHANCE
CONVECTION ACROSS NORTHERN CENTRAL AMERICA AND THE SOUTHERN STATES
OF MEXICO. INITIALLY EXPECTING RAINFALL AMOUNTS OF 05-10MM/DAY AND
MAXIMA OF 15MM. THROUGH THURSDAY IT IS TO INCREASE TO 10-15MM/DAY
AND MAXIMA OF 20-40MM.

ITCZ CONVECTION ACROSS SOUTHERN NICARAGUA-COSTA RICA-PANAMA IS TO
FAVOR RAINFALL AMOUNTS OF 15-20MM/DAY AND MAXIMA OF 25-50MM.
HIGHER AMOUNTS...HOWEVER...ARE HIGHLY LIKELY AS FAVORABLE MJO
CONDITIONS PERSIST OVER THE EASTERN TROPICAL PACIFIC. ACROSS THE
ANDEAN REGION AND WESTERN PLAINS OF COLOMBIA/SIERRA NEVADA DE
SANTA MARTA ALSO EXPECTING ACCUMULATION OF 15-20MM/DAY AND MAXIMA
OF 25-50MM...WHILE OVER NORTHWEST VENEZUELA THE NET IS TO FAVOR
RAINFALL AMOUNTS OF 10-15MM/DAY AND MAXIMA OF 20-35MM.

ANOTHER TUTT TO THE EAST...WITH A LOW NORTH OF THE ISLANDS NEAR
26N 71W... SEPARATES THE SUBTROPICAL RIDGE FROM THE SUBEQUATORIAL
RIDGE. AT 250 HPA THE SUBTROPICAL RIDGE CONFINES TO THE FAR
WESTERN ATLANTIC. THE SUBEQUATORIAL RIDGE...MEANWHILE...EXTENDS
ACROSS THE TROPICAL ATLANTIC TO THE EASTERN CARIBBEAN. UNDER
INFLUENCE OF THE SUBTROPICAL RIDGE TO THE WEST...THE TUTT LOW IS
TO MEANDER ACROSS THE BAHAMAS TO EASTERN CUBA THROUGH THURSDAY
EVENING. AT MID-LOW LEVELS...A BROAD RIDGE DOMINATES THE WESTERN
ATLANTIC-CARIBBEAN BASIN. MID LEVEL REFLECTION OF THE TUTT
ALOFT...HOWEVER...SPLITS THIS PATTERN AS IT EXTENDS ACROSS THE
WINDWARD PASSAGE/THE BAHAMAS. THROUGH THURSDAY THIS BECOMES BETTER
ORGANIZED AS A CLOSED LOW FORMS OVER EASTERN CUBA. AS THE TUTT
MEANDERS WEST ACROSS CUBA THIS IS TO ENHANCE DIURNAL CONVECTION.
EARLY IN THE CYCLE EXPECTING RAINFALL AMOUNTS OF 00-05MM/DAY AND
MAXIMA OF 10MM...WHILE WEDNESDAY THIS IS TO INCREASE TO
05-10MM/DAY AND MAXIMA OF 15MM. OVER JAMAICA EXPECTING RAINFALL
AMOUNTS OF 05-10MM/DAY AND MAXIMA OF 15MM. OVER CENTRAL HISPANIOLA
A SLIGHT INCREASE IN CONVECTION IS EXPECTED ON TUESDAY TO
WEDNESDAY...WITH RAINFALL AMOUNTS OF 00-05MM/DAY AND MAXIMA OF
10MM...INCREASING TO 05-10MM/DAY AND MAXIMA OF 15MM ON THURSDAY.

THE ATLANTIC ITCZ IS TO ENHANCE MOISTURE CONVERGENCE ACROSS
NORTHERN GUYANA/NORTHEAST VENEZUELA THROUGH WEDNESDAY
MORNING...WHEN A DRYER/SAHARAN AIR LAYER IS TO FAVOR SHARP DROP IN
AVAILABLE MOISTURE. MEANWHILE... EXPECTING RAINFALL AMOUNTS OF
10-15MM/DAY AND MAXIMA OF 20-35MM. THROUGH THURSDAY IT DECREASES
TO 05-10MM/DAY AND MAXIMA OF 15MM.

TROPICAL/EASTERLY WAVES INITIALIZED AT 12UTC
INITIAL  24     36     48     60     72     84     96        TYPE
64W      68W    74W    78W    82W    85W    88W    90W       TW
78W      81W    84W    87W    90W    93W    95W    97W       TW

91W      94W    97W    101W   103W   105W   107W   109W      TW

TROPICAL WAVE ALONG 64W AND SOUTH OF 17N IS TO ENHANCE CONVECTION
ALONG THE NET OVER NORTHERN VENEZUELA...WHERE WE EXPECT RAINFALL
AMOUNTS OF 05-10MM/DAY AND MAXIMA OF 15-20MM. ACROSS NORTHWEST
VENEZUELA-NORTHERN COLOMBIA THIS IS TO THEN FAVOR RAINFALL AMOUNTS
OF 10-15MM/DAY AND MAXIMA OF 20-35MM EARLY ON WEDNESDAY. AS IT
MOVES ACROSS THE EASTERN-CENTRAL CARIBBEAN A MOIST PLUME IS TO
TRAIL THIS WAVE. THIS AFFECTS PUERTO RICO-VIRGIN ISLES THROUGH
WEDNESDAY MORNING...WITH RAINFALL AMOUNTS OF 00-05MM/DAY AND
MAXIMA OF 10MM...WHILE OVER HISPANIOLA-JAMAICA EXPECTING RAINFALL
AMOUNTS OF 05-10MM/DAY AND MAXIMA OF 15MM. OVER PANAMA-COSTA
RICA-NICARAGUA...IN INTERACTION WITH THE ITCZ...EXPECTING RAINFALL
AMOUNTS OF 15-20MM/DAY AND MAXIMA OF 25-50MM. OVER EL
SALVADOR-SOUTHERN HONDURAS TO GUATEMALA IT IS TO THEN FAVOR
RAINFALL AMOUNTS OF 10-15MM/DAY AND MAXIMA OF 20-40MM.

TROPICAL WAVE ALONG 78W CONTINUES TO INTERACT WITH THE ITCZ OVER
PANAMA-COSTA RICA-SOUTHERN NICARAGUA...WHERE IT IS TO TRIGGER
RAINFALL AMOUNTS OF 15-20MM/DAY AND MAXIMA OF 35-70MM. ON
WEDNESDAY...AS IT PHASES WITH DEEPENING TUTT OVER SOUTHERN
MEXICO/NORTHERN CENTRAL AMERICA...THIS WILL ENHANCE CONVECTIVE
DEVELOPMENT ACROSS EL SALVADOR-HONDURAS-GUATEMALA...WITH RAINFALL
AMOUNTS OF 10-15MM/DAY AND MAXIMA OF 20-30MM...WHILE OVER SOUTHERN
MEXICO THIS IS TO PEAK AT 20-40MM.

TROPICAL WAVE ALONG 91W IS TO ALSO INTERACT WITH DEEPENING TUTT
OVER SOUTHERN MEXICO...TO TRIGGER SCATTERED CONVECTION WITH
RAINFALL AMOUNTS OF 15-20MM/DAY AND MAXIMA OF 25-50MM.

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




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