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Tropical Discussion
 
(Caution: Version displayed is not the latest version. - Issued 1541Z Jul 02, 2020)
 
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TROPICAL DISCUSSION - INTERNATIONAL DESKS
NWS WEATHER PREDICTION CENTER COLLEGE PARK MD
1141 AM EDT THU JUL 02 2020

TROPICAL DISCUSSION FROM JULY 02/16 UTC: IN MEXICO...A ROBUST CELL
OF THE SUBTROPICAL UPPER RIDGE CENTERS OVER SINALOA/DURANGO. TO
THE SOUTHEAST OF THIS CELL...A TUTT LOW CENTERS OVER THE WESTERN
YUCATAN PENINSULA AND INTO THE TEHUANTEPEC REGION. BOTH SYSTEMS
ARE FORECAST TO RETROGRESS. BY SATURDAY...THE RIDGE IS FORECAT TO
EXTEND OVER SOUTHERN SONORA/CENTRAL BAJA CALIFORNIA
PENINSULA...WHILE THE TUTT BECOMES AN ELONGATED TROUGH EXTENDING
FROM SOUTHWEST MEXICO ACROSS NORTHERN VERACRU INTO THE
NORTH-CENTRAL GULF OF MEXICO. IN THE MID- AND LOW TROPOSPHERE...A
TROPICAL WAVE WILL ENHANCE CONVECTION IN NORTHERN CENTRAL AMERICA
AND SOUTHERN MEXICO IN INTERACTION WITH THE TUTT. OTHER REGION
WHERE MOISTURE AVAILABILITY WILL BE SUFFICIENT TO SUSTAIN MODERATE
PRECIPITATION - BUT WITHIN THE SEASONAL VARIABILITY - IS THE
SIERRA MADRE OCCIDENTAL.

IN NORTHWEST MEXICO...EXPECTING LARGEST ACCUMULATIONS IN THE
SIERRA MADRE OCCIDENTAL OF SONORA/NORTHERN SINALOA AND CHIHUAHUA
ON THURSDAY AND FRIDAY...TO SUSTAIN 10-15MM/DAY AND MAXIMA OF
20-40MM...DECREASING TO 05-10MM/DAY AND ISOLATED MAXIMA OF 15-30MM
BY SATURDAY INTO SUNDAY. SIMILARLY...ACTIVITY IN CHIHUAHUA/EASTERN
COAHUILA IS EXPECTED TO DECREASE IN COVERAGE AND INTENSITY FROM
05-10MM/DAY AND MAXIMA OF 15-25MM ON THURSDAY...TO ISOLATED
CONVECTION BY SATURDAY. IN SOUTHERN AND CENTRAL MEXICO...TROPICAL
WAVE CONVECTION WILL INTERACT POSITIVELY WITH THE TUTT ON
THURSDAY...TO SUSTAIN 10-15M/DAY AND MAXIMA OF 20-45MM FROM
WESTERN EL SALVADOR/SOUTHERN BELIZE INTO OAXACA/CAMPECHE AND
TABASCO. TO THE WEST ACROSS CENTRAL AND SOUTHWEST MEXICO EXPECTING
05-10MM/DAY AND MAXIMA OF 15-25MM. IN THE NORTHERN YUCATAN
PENINSULA EXPECTING MAXIMA OF 15MM. ON FRIDAY...LARGEST AMOUNTS
ARE EXPECTED FROM SOUTHERN BELIZE/GUATEMALA INTO OAXACA AND
EASTERN PUEBLA...WHERE TROPICAL WAVE WILL FAVOR 10-15MM/DAY AND
MAXIMA OF 20-40MM. WEST ACROSS CENTRAL AND SOUTHWEST MEXICO
EXPECTING 05-10MM/DAY AND MAXIMA OF 15-30MM. ON SATURDAY...ANOTHER
TROPICAL WAVE WILL ENHANCE CONVECTION IN
BELIZE/GUATEMALA/CHIAPAS/TABASCO AND CAMPECHE...WHERE IT WILL
AGAIN FAVOR 10-15MM/DAY AND ISOLATED MAXIMA OF 20-40MM. IN THE
YUCATAN PENINSULA THE TROPICAL WAVE WILL FAVOR 05-10MM/DAY AND
MAXIMA OF 15-25MM.

TO THE SOUTHEAST AND AT UPPER LEVELS...A CELL OF THE SUBEQUATORIAL
RIDGE HAS BUILT IN THE CENTRAL/WESTERN CARIBBEAN...AND IS FORECAST
TO RETROGRESS WESTWARD TO CENTER JUST TO THE NORTH OF HONDURAS BY
SATURDAY EVENING...AND OVER NORTHERN GUATEMALA BY SUNDAY EVENING.
TO THE EAST OF THE RIDGE...A TUTT IS ALSO INTENSIFYING AND IS ALSO
FORECAST TO RETROGRESS. ON THURSDAY...THE TUTT CENTERS OVER THE
LEEWARD ISLANDS...AND IS FORECAST TO DEVELOP A MERIDIONAL
TROUGH...THAT WILL MEANDER WESTWARD TO EXTEND ALONG NORTHWEST
COLOMBIA INTO THE DOMINICAN REPUBLIC BY SUNDAY EVENING. ALTHOUGH
THESE SYSTEMS WILL PROVIDE SOME VENTILATION FOR CONVECTION...THERE
ARE LIMITED AMOUNTS OF AVAILABLE MOISTURE IN THE CARIBBEAN
BOUNDARY LAYER. UNDER THE ABSENCE OF A STRONG SUBSIDENCE
INVERSION...VERTICAL MIXING WITH THE DRY AIR ALOFT WILL CONTINUE
LIMITING THE COVERAGE OF CONVECTION SIGNIFICANTLY...AND ALSO LIMIT
THE POTENTIAL RAINFALL ACCUMULATIONS. THIS WILL LEAD TO ANY
MODERATE PRECIPITATION AMOUNTS TO BE VERY ISOLATED. WAVES IN THE
TRADES ARE PLAYING A ROLE IN MODULATING CONVECTION...BUT EXPECTED
ACCUMULATIONS WILL BE GENERALLY LIGHT IN THE ENTIRE CARIBBEAN
BASIN...WITH THE EXCEPTION OF NICARAGUA/COSTA RICA AND PANAMA.

IN TERMS OF RAINFALL ACCUMULATIONS IN THE CARIBBEAN...ON
THURSDAY...LARGEST AMOUNTS ARE EXPECTED IN PUERTO RICO AND IN
HISPANIOLA...WHERE DIURNAL CONVECTION WILL SUSTIN 05-10MM/DAY AND
MAXIMA OF 15-20MM. IN CUBA...EXPECTING 05-10MM/DAY AND MAXIMA FO
15MM. ELSEWHERE...EXPECTING VERY ISOLATED CONVECTION AND LIGHT
PRECIPITATION. ON FRIDAY...LARGEST AMOUNTS ARE EXPECTED IN
HISPANIOLA AND CUBA...WHERE DIURNAL CONVECTION WILL SUSTAIN
05-10MM/DAY AND MAXIMA OF 15MM. IN JAMAICA...PUERTO RICO AND THE
CENTRAL LESSER ANTILLES EXPECTING MAXIMA GENERALLY UNDER 10MM/DAY.
ON SATURDAY...LARGEST AMOUNTS ARE EXPECTED IN HAITI...WHERE
DIURNAL CONVECTION WILL SUSTAIN 05-10MM/DAY AND MAXIMA OF 15-20MM.
IN CENTRAL CUBA...TROPICAL WAVE CONVECTION WILL SUSTAIN MAXIMA OF
15MM. SIMILAR AMOUNTS ARE EXPECTED IN PUERTO RICO AND IN THE
NORTHWEST BAHAMAS. TROPICAL WAVE WILL ALSO ENHANCE CONVECTION IN
JAMAICA...BUT UNDER LIMITED AMOUNTS OF MOISTURE...EXPECTING
ISOLATED MAXIMA GENERALLY UNDER 10MM/DAY. IN THE CENTRAL AND
NORTHERN LESSER ANTILLES EXPECTING 00-05MM/DAY AND ISOLATED MAXIMA
OF 10MM.

A MUCH MORE ACTIVE PATTERN OF CONVECTION IS EXPECTED IN SOUTHERN
CENTRAL AMERICA AND IN COLOMBIA...WHERE THE PANAMANIAN LOW IS
FORECAST TO REMAIN ACTIVE AND A DEEP-LAYER POOL OF PRECIPITABLE
WATER WILL SUSTAIN MODERATE TO LOCALLY HEAVY PRECIPITATION AMOUNTS
ON A DAILY BASIS. TROPICAL WAVES WILL ALSO PLAY A ROLE IN
ENHANCING CONVECTION...ESPECIALLY ON SATURDAY...WHEN ACTIVE
CONVECTION IS EXPECTED IN THE GULF OF PANAMA REGION. ON
THURSDAY...LARGEST ACCUMULATIONS ARE EXPECTED IN WESTERN COLOMBIA
WHERE DIURNAL CONVECTION...ENHANCED BY LOW-LEVEL WESTERLIES...WILL
SUSTAIN 15-20MM/DAY AND MAXIMA OF 25-50MM. IN NORTHERN
COLOMBIA...AS WELL AS IN PANAMA AND COSTA RICA/SOUTHEAST
NICARAGUA...EXPECTING 10-15MM/DAY AND MAXIMA OF 20-35MM. ON
FRIDAY...LARGEST ACCUMULATIONS ARE EXPECTED IN
CENTRAL...NORTHERN...AND WESTERN COLOMBIA...WHERE CONVECTION WILL
SUSTAIN 15-20MM/DAY AND MAXIMA OF 35-70MM. IN PANAMA...COSTA RICA
AND EASTERN NICARAGUA EXPECTING 10-15MM/DAY AND MAXIMA OF 20-40MM.
ON FRIDAY...LARGEST AMOUNTS ARE EXPECTED IN WESTERN PANAMA AND
SOUTHERN COSTA RICA...AS WELL AS IN WESTERN COLOMBIA...WHERE DEEP
CONVECTION WILL SUSTAIN 15-30MM/DAY AND MAXIMA OF 40-80MM AS
ENHANCED BY A TROPICAL WAVE. IN CENTRAL AND NORTHERN COLOMBIA
EXPECTING 15-20MM/DAY AND MAXIMA OF 35-70MM. IN PANAMA AND IN
NORTHERN COSTA RICA/SOUTHEAST NICARAGUA EXPECTING 15-20MM/DAY AND
MAXIMA OF 25-50MM.

TO THE EAST ACROSS VENEZUELA AND THE GUIANAS...CONVECTION WILL BE
PRIMARILY ACTIVE ALONG THE ITCZ/NET. THE NET IS FORECAST TO
MEANDER ACROSS NORTHERN GUIANA ON A DAILY BASIS...TO SUSTAIN
MODERATE PRECIPITATION THROUGH THE CYCLE. ON THURSDAY...EXPECTING
LARGEST AMOUNTS IN THE AMAZON BASIN OF COLOMBIA AND VENEZUELA
WHERE EXPECTING 10-15MM/DAY AND MAXIMA OF 20-40MM. IN NORTHERN
GUYANA...CENTRAL VENEZUELA AND WESTERN VENEZUELA EXPECTING
05-10MM/DAY AND MAXIMA OF 15-30MM. IN NORTHERN SURINAME AND IN
FRENCH GUIANA EXPECTING 05-10MM/DAY AND MAXIMA OF 15-20MM. ON
FRIDAY...LARGEST AMOUNTS ARE EXPECTED IN CENTRAL VENEZUELA AND IN
EASTERN COLOMBIA/THE WESTERN ORINOQUIA OF VENEZUELA...WHERE
DIURNAL CONVECTION ENHANCED BY A TROPICAL WAVE WILL SUSTAIN
15-20MM/DAY AND MAXIMA OF 25-50MM. IN NORTHERN GUYANA...NET
CONVECTION WILL FAVOR 10-15MM/DAY AND MAXIMA OF 20-35MM. IN FRENCH
GUIANA AND SURINAME EXPECTING 05-10MM/DAY AND MAXIMA OF
15-20MM...ENHANCED BY A TUTT-INDUCED PERTURBATION ARRIVING FROM
THE ATLANTIC. BY SATURDAY...CONVECTION ALONG THE NET WILL FAVOR
10-15MM/DAY AND MAXIMA OF 20-45MM FROM NORTHERN GUYANA ACROSS
SOUTHERN VENEZUELA INTO MOST OF THE COLOMBIAN ORINOQUIA AND AMAZON
BASIN. ELSEWHERE IN THE GUIANAS EXPECTING 05-10MM/DAY AND MAXIMA
OF 15-20MM.

TROPICAL/EASTERLY WAVES INITIALIZED ON JULY 02 AT 12 UTC:
TYPE - 02/12 03/00 03/12 04/00 04/12 05/00 05/12 06/00 SOF
TI   -   40W   44W   48W   52W   55W   58W   61W   64W 20N
TW   -   59W   63W   66W   70W   74W   78W   82W   86W 17N
TW   -   71W   74W   78W   82W   86W   90W   93W   97W 24N
TW   -   73W   DISS  ---   ---   ---   ---   ---   --- 25N
TI   -   79W   81W   DISS  ---   ---   ---   ---   --- 25N
TW   -   90W   92W   94W   95W   97W   99W  102W  104W 16N
TW   -  103W  106W  109W  112W  115W  118W EXITS   --- 15N

A TUTT-INDUCED PERTURBATION IS INITIALIZED AT 40W AND TO THE SOUTH
OF 20N. THIS PERTURBATION IS FORECAST TO PROPAGATE WESTWARD AND
ENTER THE CARIBBEAN BY SUNDAY JULY 5TH. HOWEVER...LIMITED AMOUNTS
OF AVAILABLE MOISTURE AND FAST PROPAGATION WILL LIMIT THE EFFECTS
OF THIS PERTURBATION IN CONVECTION. ON SATURDAY...THIS WAVE WILL
FAVOR 10-15MM/DAY AND MAXIMA OF 20-40MM IN NORTHERN GUYANA...IN
INTERACTION WITH ITCZ CONVERGENCE. IN THE LESSER ANTILLES...IT
WILL FAVOR INCREASED COVERAGE OF TRADE WIND SHOWERS...TO SUSTAIN
00-05MM/DAY AND MAXIMA OF 10MM.

A TROPICAL WAVE IS INITIALIZED AT 59W AND TO THE SOUTH OF 17N. AS
THE WAVE IS EMBEDDED IN A DRY AIR MASS...ITS EFFECTS ON CARIBBEAN
CONVECTION WILL BE LIMITED...AND WILL ENHANCE CONVECTION MOSTLY IN
NORTHERN SOUTH AMERICA AND SOUTHERN CENTRAL AMERICA. ON
THURSDAY...THE WAVE WILL FAVOR 05-10MM/DAY AND MAXIMA OF 15-30MM
IN EASTERN VENEZUELA AND NORTHERN GUYANA...WHILE IN THE ARC OF THE
LESSER ANTILLES IT WILL EXERT LIMITED EFFECTS IN CONVECTION. ON
FRIDAY...THE WAVE WILL INTERACT WITH A MOISTER AIR MASS IN
WESTERN/SOUTHERN VENEZUELA AND NORTHEAST COLOMBIA TO SUSTAIN
15-20MM/DAY AND MAXIMA OF 25-50MM. IN CENTRAL COLOMBIA EXPECTING
15-20MM/DAY AND MAXIMA OF 35-70MM. ON SATURDAY...THE WAVE WILL
STIMULATE CONVECTION IN THE GULF OF PANAMA REGION. GIVEN THE
PRESENCE OF AN ACTIVE PANAMANIAN LOW...IT WILL FAVOR 15-30MM/DAY
AND MAXIMA OF 40-80MM IN SOUTHERN COSTA RICA AND WESTERN
PANAMA...AS WELL AS IN WESTERN COLOMBIA. IN CENTRAL PANAMA AND IN
NORTHERN COSTA RICA/SOUTHEAST NICARAGUA...THIS WILL FAVOR
15-20MM/DAY AND MAXIMA OF 25-50MM.

A LARGE TROPICAL WAVE IS INITIALIZED AT 62W AND TO THE SOUTH OF
24N. ON THURSDAY...THE WAVE WILL STIMULATE CONVECTION IN WESTERN
VENEZUELA AND NORTHERN COLOMBIA WHERE IT WILL SUSTAIN 10-15MM/DAY
AND MAXIMA OF 20-35MM. IN HISPANIOLA AND PUERTO RICO...THIS WILL
SUSTAIN 05-10MM/DAY AND MAXIMA OF 15-20MM. ON FRIDAY...THE WAVE
WILL ENHANCE CONVECTION IN CENTRAL AND WESTERN COLOMBIA...TO
SUSTAIN 15-20MM/DAY AND MAXIMA OF 35-70MM. IN THE NORTHERN
CARIBBEAN...ENHANCEMENT WILL BE LIMITED DUE TO LIMITED AMOUNTS OF
AVAILABLE MOISTURE AND STRONG LOW-LEVEL WINDS. THIS WILL LIMIT
MAXIMA FO 10MM/DAY IN JAMAICA AND TO 15MM/DAY IN EASTERN AND
CENTRAL CUBA. ON SATURDAY...THE WAVE IS FORECAST TO PROPAGATE
ACROSS EL SALVAROD/BELIZE/GUATEMALA INTO CHIAPAS. THIS WILL
SUSTAIN 10-15MM/DAY AND MAXIMA OF 20-40MM IN BELIZE/GUATEMALA AND
AREAS TO THE WEST INTO CHIAPAS/TABASCO. IN EL SALVADOR AND
HONDURAS THE WAVE WIL SUSTAIN 05-10MM/DAY AND MAXIMA OF 15-20MM.

A VERY WEAK TROPICAL WAVE IS INITIALIZED AT 73W BUT IT IS RAPIDLY
LOSING DEFINITION AS IT PROPAGATES ACROSS HAITI AND SOUTHEAST CUBA
ON THURSDAY.

A TUTT INDUCED PERTURBATION IS INITIALIZED AT 79W AND TO THE SOUTH
OF 25N...BUT IT IS ALSO RAPIDLY LOSING DEFINITION AS IT PROPAGATES
ACROSS CUBA AND THE CAYMAN ISLANDS ON THURSDAY.

A TROPICAL WAVE IS INITIALIZED AT 90W AND IS PROPAGATING SLOWLY TO
THE SOUTH OF 16N. ON THURSDAY...THE NORTHERN TIER OF THE WAVE IS
FORECAST TO INTERACT WITH A TUTT OVER NORTHERN CENTRAL
AMERICA...TO FAVOR 10-15MM/DAY AND MAXIMA OF 20-45MM FROM WESTERN
EL SALVADOR/WESTERN HONDURAS THROUGH SOUTHERN OAXACA AND CAMPECHE
IN MEXICO. ON FRIDAY...THE WAVE WILL FAVOR MAXIMA OF 20-40MM FROM
NORTHERN GUATEMALA THROUGH EASTERN PUEBLA/OAXACA IN MEXICO. ON
SATURDAY...THE NORTHERN TIER OF THE WAVE WILL PROPAGATE ACROSS
GUERRERO IN MEXICO...TO FAVOR 05-10MM/DAY AND MAXIMA OF 15-30MM.

A TROPICAL WAVE IS INITIALIZED AT 103W AND WILL HAVE INDIRECT
EFFECTS IN CONVECTION AS MOIST PLUME TO THE EAST OF THE WAVE AXIS
ENTERS THE GULF OF CALIFORNIA REGION...TO SUSTAIN ACCUMULATIONS OF
10-15MM/DAY AND MAXIMA OF 20-40MM IN THE SIERRA MADRE OCCIDENTAL
THROUGH FRIDAY.

GALVEZ/DAVISON...WPC (USA)