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Tropical Discussion
 
(Caution: Version displayed is not the latest version. - Issued 1757Z Jul 08, 2020)
 
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TROPICAL DISCUSSION - INTERNATIONAL DESKS
NWS WEATHER PREDICTION CENTER COLLEGE PARK MD
157 PM EDT WED JUL 08 2020

TROPICAL DISCUSSION FROM JULY 08/16 UTC: AT 15 UTC...TROPICAL
STORM CRISTINA CENTERED AT 14.6N 106.9W. MINIMUM CENTRAL PRESSURE
WAS 998 HPA AND MAXIMUM SUSTAINED WINDS 50KT WITH GUSTS TO 60KT.
CRISTINA WAS MOVING TO THE NORTHWEST OR 310 DEGREES AT 10KT.

IN MEXICO...CONVECTION WILL BE PRIMARILY ENHANCED IN CENTRAL AND
WESTERN PORTIONS OF THE COUNTRY...WHERE DEEPER-LAYER MOISTURE WILL
BE IN PLACE. ACTIVITY WILL BE MOSTLY ENHANCED INDIRECTLY BY
CRISTINA...BUT AS CRISTINA MOVES AWAY AND A DRIER AIR MASS ARRIVES
FROM THE EAST...EXPECTING A DECREASE IN ACCUMULATIONS INTO THE
EARLY WEEKEND. IN THE UPPER LEVELS...A TUTT IS RETROGRESSING FROM
THE WESTERN GULF OF MEXICO ON WEDNESDAY TO CENTER OVER COLIMA BY
FRIDAY. HOWEVER...ENHANCED SHEAR IN THE NORTHERN PERIPHERY OF THE
TUTT WILL ALSO LIMIT POTENTIAL ACCUMULATIONS AS THE CYCLE
PROGRESSES. ON WEDNESDAY...LARGEST ACCUMULATIONS ARE EXPECTED IN
CENTRAL MEXICO AND ALONG THE SIERRA MADRE OCCIDENTAL OF SINALOA
AND SONORA...WHERE EXPECTING 15-20MM/DAY AND MAXIMA OF 25-50MM. IN
SOUTHWEST MEXICO EXPECTING 05-10MM/DAY AND MAXIMA OF 15-25MM. A
DRY AIR MASS ARRIVING FROM THE CARIBBEAN WILL SUSTAIN MAXIMA UNDER
15MM/DAY IN AREAS TO THE EAST OF 98W AND ISOLATED CONVECTION. ON
THURSDAY...LARGEST AMOUNTS ARE EXPECTED BETWEEN JALISCO/COLIMA AND
SINALOA...WHERE DIURNAL CONVECTION WILL SUSTAIN 10-15MM/DAY AND
MAXIMA OF 20-40MM. DIURNAL CONVECTION IN CENTRAL MEXICO AND IN THE
NORTHERN SIERRA MADRE OCCIDENTAL WILL FAVOR 05-10MM/DAY AND MAXIMA
OF 15-25MM. ON THURSDAY...EXPECTING 05-10MM/DAY AND ISOLATED
MAXIMA OF 15-20MM IN THE EJE VOLCANICO CENTRAL AND MOST OF THE
SIERRA MADRE OCCIDENTAL. LARGER ACCUMULATIONS ARE EXPECTED IN
SOUTHEAST MEXICO...AS TWO TROPICAL WAVES ARRIVE FROM CENTRAL
AMERICA. THESE WILL FAVOR 15-20MM/DAY AND MAXIMA OF 30-60MM IN THE
GULF OF TEHUANTEPEC REGION...AND 10-15MM/DAY AND MAXIMA OF 20-40MM
IN CHIAPAS AND VERACRUZ. IN THE YUCATAN PENINSULA EXPECTING MAXIMA
OF 15M.

IN THE CARIBBEAN...A SIGNIFICANT DRYING TREND IS UNDERWAY UNDER
THE INFLUENCE OF A DRY AIR MASS ARRIVING FROM THE ATLANTIC AND AN
ACCELERATION OF THE TRADES. INITIALLY...A ROBUST TROPICAL WAVE
WILL ENHANCE ACCUMULATIONS IN HISPANIOLA ON WEDNESDAY TO FAVOR
10-15MM/DAY AND MAXIMA OF 25-50MM...AS IT INTERACTS WITH A WEAK
TUTT TO THE NORTH. SIMILARLY...ANOTHER TROPICAL WAVE WILL ENHANCE
CONVECTION IN JAMAICA AND SOUTHEAST CUBA...TO FAVOR 05-10MM/DAY
AND MAXIMA OF 15-25MM. HOWEVER...ON THURSDAY...ACCUMULATIONS IN
HISPANIOLA AND AREAS TO THE EAST WILL BE LIMITED IN COVERAGE AND
TO MAXIMA UNDER 10MM/DAY. HOWEVER...THE MOIST PLUME ASSOCIATED
WITH THE TROPICAL WAVE WILL INTERACT WITH FAVORABLE UPPER
DIVERGENCE IN THE SOUTHEASTERN PERIPHERY OF AN UPPER RIDGE OVER
THE BAHAMAS...TO FAVOR 10-15MM/DAY AND MAXIMA OF 20-35MM ON
THURSDAY. IN CUBA THIS WILL SUSTAIN 05-10MM/DAY AND MAXIMA OF
15-25MM...WHILE IN THE CAYMAN ISLANDS AND JAMAICA EXPECTING MAXIMA
UNDER 15MM/DAY. ON FRIDAY...LARGEST AMOUNTS WILL CLUSTER WITH THE
AFOREMENTIONED MOIST PLUME IN CENTRAL/WESTERN CUBA AND IN THE
NORTHWEST BAHAMAS WHERE EXPECTING 10-15MM/DAY AND MAXIMA OF
20-35MM. ALSO ON FRIDAY...ANOTHER TROPICAL WAVE ENTERS THE ARC OF
THE LESSER ANTILLES...BUT UNDER LIMITED AMOUNTS OF AVAILABLE
MOISTURE...MAXIMA WILL BE GENERALLY LIMITED TO 10MM/DAY. IN
NORTHEAST VENEZUELA AND TRINIDAD AND TOBAGO...EXPECTING
10-15MM/DAY AND MAXIMA OF 20-40MM.

IN CENTRAL AMERICA...TROPICAL WAVES ARRIVING INTO PANAMA/COSTA
RICA ON WEDNESDAY WILL SUSTAIN AN INCREASE IN ACCUMULATIONS. THE
DRY AIR MASS TRAILING BEHIND THE SECOND TROPICAL WAVE WILL SUSTAIN
A NOTICEABLE DRYING TREND IN AREAS TO THE NORTH OF CENTRAL
NICARAGUA FROM LATE THURSDAY AND ON. HOWEVER...ITCZ CONVECTION
WILL BE ACTIVE IN THE PANAMA/COSTA RICA REGION AND IN NORTHWEST
COLOMBIA IN ASSOCIATION WITH AN ACTIVE ITCZ AND A TRIOPOSPHERIC
KELVIN WAVE TRANSVERSING THE REGION THROUGH THE EARLY WEEKEND.
THIS WILL FAVOR 15-20MM/DAY AND MAXIMA OF 30-60MM ON FRIDAY. IN
THE MEAN TIME...ON WEDNESDAY...TROPICAL WAVE ENTERS PANAMA TO
REINFORCE THE PANAMANIAN LOW CIRCULATION. THIS WILL SUSTAIN
15-20MM/DAY AND MAXIMA OF 30-60MM FROM CENTRAL PANAMA INTO
SOUTHERN COSTA RICA...AND POTENTIALLY ISOLATED LARGER AMOUNTS IN
THE BOCAS DEL TORO REGION. IN NORTHERN COSTA RICA AND EASTERN
NICARAGUA EXPECTING AN INCREASE INTO 10-15MM/DAY AND MAXIMA OF
15-30MM/ SIMILAR AMOUNTS ARE EXPECTED IN EASTERN PANAMA AND
NORTHWEST COLOMBIA. IN NORTHERN CENTRAL AMERICA WEST INTO SOUTHERN
MEXICO...EXPECTING ISOLATED CONVECTION TO SUSTAIN 05-10MM/DAY AND
MAXIMA OF 15MM. ON THURSDAY...LARGEST ACCUMULATIONS ARE EXPECTED
IN COSTA RICA AND IN EASTERN NICARAGUA/EASTERN HONDURAS...WHERE
MOIST PLUME ASSOCIATED WITH TROPICAL WAVE WILL FAVOR 15-20MM/DAY
AND MAXIMA OF 30-60MM. IN HONDURAS...EL SALVADOR AND
SOUTHERN/CENTRAL GUATEMALA EXPECTING 05-10MM/DAY AND MAXIMA OF
15-25MM. SIMILAR AMOUNTS ARE EXPECTED IN MOST OF PANAMA.

IN NORTHERN SOUTH AMERICA...TROPICAL WAVES AND THE NET WILL PLAY
AN IMPORTANT ROLE IN MODULATONG CONVECTION. AS A DRY AIR MASS
PROPAGATES ACROSS THE CARIBBEAN...EXPECTING A RELOCATION OF THE
AREAS OF HEAVIEST PRECIPITATION FORM EXTREME NORTHERN SOUTH
AMERICA EARLY IN THE CYCLE INTO SOUTH-CENTRAL VENEZUELA AND
CENTRAL COLOMBIA BY THURSDAY. SEE THE TROPICAL WAVE SECTION FOR
RAINFALL ACCUMULATIONS.

TROPICAL/EASTERLY WAVES INITIALIZED ON JULY 08 AT 12 UTC:
TYPE - 08/12 09/00 09/12 10/00 10/12 11/00 11/12 12/00 SOF
TW   -   39W   43W   47W   51W   55W   60W   65W   69W 10N
TW   -   69W   73W   77W   81W   85W   88W   91W   94W 21N
TW   -   76W   79W   82W   86W   90W   93W   96W   99W 22N
TI   -   86W   91W   94W   DISS  ---   ---   ---   --- 20N
TW   -  102W  DISS   ---   ---   ---   ---   ---   --- 16N

A TROPICAL WAVE IS INITIALIZED AT 39W. THE WAVE WILL ARRIVE INTO
FRENCH GUIANA ON THURSDAY TO SUSTAIN MAXIMA OF 15MM. NORTH ACROSS
SURINAME AND NORTHERN GUYANA EXPECTING MAXIMA OF 15-30MM IN
ASSOCIATION WITH ITCZ CONVERGENCE. ON FRIDAY...THE WAVE WILL
STIMULATE CONVECTION IN TRINIDAD AND TOBAGO AND IN NORTHEAST
VENEZUELA TO FAVOR 10-15MM/DAY AND MAXIMA OF 20-40MM. IN GUYANA
EXPECTING 05-10MM/DAY AND MAXIMA OF 15-25MM. IN THE LESSER
ANTILLES...LIMITED MOISTURE WILL FAVOR MAXIMA UNDER 10MM/DAY.

A ROBUST TROPICAL WAVE IS INITIALIZED AT 69W. THIS IS THE MOST
SIGNIFICANT TROPICAL WAVE IN THE BASIN AND IS ASSOCIATED WITH AN
IMPORTANT MOIST PLUME. HOWEVER...DRY AIR MASS TRAILS BEHIND THE
WAVE AXIS...TO SUSTAIN A NOTICEABLE DRYING TREND AS IT PROPAGATES
ACROSS THE CARIBBEAN. ON WEDNESDAY...THE WAVE IS EXPECTED TO
INTERACT WITH A TUTT NEAR HISPANIOLA TO SUSTAIN 15-20MM/DAY AND
MAXIMA OF 25-50MM. SIMILAR AMOUNTS ARE EXPECTED IN THE LAKE
MARACAIBO REGION AND NORTHERN/CENTRAL COLOMBIA. ON THURSDAY...THE
WAVE WILL STIMULATE CONVECTION IN COSTA RICA...EASTERN NICARAGUA
AND WESTERN PANAMA WHERE EXPECTING 15-20MM/DAY AND MAXIMA OF
30-60MM. IN THE CAYMAN ISLANDS IT WILL FAVOR MAXIMA OF 15MM...IN
CUBA 05-10MM/DAY AND MAXIMA OF 15-25MM...WHILE IN THE SOUTHEAST
BAHAMAS EXPECTING 10-15MM/DAY AND MAXIMA OF 20-35MM. ON
FRIDAY...THE WAVE WILL STIMULATE CONVECTION IN NORTHERN CENTRAL
AMERICA TO SUSTAIN 10-15MM/DAY AND MAXIMA OF 20-40MM FROM CENTRAL
HONDURAS AND THE GULF OF FONSECA REGION WEST INTO GUATEMALA AND
SOUTHERN BELIZE. IN THE UICATAN PENINSULA EXPECTING MAXIMA OF
15MM. IN CENTRAL AND WESTERN CUBA...TRAILING MOISTURE WILL SUSTAIN
10-15MM/DAY AND MAXIMA OF 20-35MM. SIMILAR ACCUMULATIONS ARE
EXPECTED IN THE CENTRAL AND NORTHWEST BAHAMAS.

A MUCH WEAKER TROPICAL WAVE IS INITIALIZED AT 76W. ON
WEDNESDAY...THE WAVE WILL ENHANCE CONVECTION IN JAMAICA AND
SOUTHEAST CUBA...WHERE IT WILL FAVOR 05-10MM/DAY AND MAXIMA OF
15-25MM. IN THE SOUTHEAST BAHAMAS EXPECTING MAXIMA OF 10MM. THE
WAVE WILL ENHANCE CONVECTION IN SOUTHERN CENTRAL AMERICA. IN
EASTERN PANAMA AND IN NORTHWEST COLOMBIA EXPECTING 05-10MM/DAY AND
MAXIMA OF 15-30MM. IN WESTERN PANAMA...COSTA RICA AND SOUTHEAST
NICARAGUA EXPECTING 10-15MM/DAY AND MAXIMA OF 20-40MM. ON
THURSDAY...THE WAVE WILL FAVOR MAXIMA OF 30-60MM IN SOUTHWEST
NICARAGUA...WHILE IN NORTHERN CENTRAL AMERICA IT FAVORS
05-10MM/DAY AND MAXIMA OF 15-25MM. ON FRIDAY...THE WAVE WILL
ENHANCE CONVECTION IN THE GULF OF TEHUANTEPEC
REGION/OAXACA...WHERE IT WILL FAVOR 15-20MM/DAY AND MAXIMA OF
30-60MM WITH THE RISK FOR MCS FORMATION. IN VERACRUZ AND CHIAPAS
EXPECTING 10-15MM/DAY AND MAXIMA OF 20-40MM.

A PERTURBATION ORIGINALLY INDUCED BY A TUTT IS DISSIPATING AS IT
CROSSES NORTHERN CENTRAL AMERICA ON WEDNESDAY...TO FAVOR MAXIMA
UNDER 15MM/DAY IN HONDURAS...EL SALVADOR AND CHIAPAS.

GALVEZ/DAVISON...WPC (USA)