782
FXCA20 KWBC 231953
PMDCA
TROPICAL DISCUSSION - INTERNATIONAL DESKS
NWS WEATHER PREDICTION CENTER COLLEGE PARK MD
352 PM EDT MON SEP 23 2024
FORECAST BULLETIN 23 SEP 2024 AT 2000 UTC:
OF NOTE: THE CENTRAL AMERICAN REGION...SOUTHERN AND EASTERN MEXICO
ARE SEEING THE EFFECTS OF A DEBILITATING CENTRAL AMERICAN GYRE
(CAG) THAT DEVELOPED LAST FRIDAY AND INTENSIFIED OVER THE WEEKEND.
THE CAG IS FAVORING AN UPPER LEVEL RIDGE OVER THE WEST
CARIBBEAN...WITH A WEAK TUTT IN THE SOUTHERN GULF OF MEXICO AND
THE YUCATAN PENINSULA. THE GENERALIZED CYCLONIC CIRCULATION OVER
THE REGION HAS FAVORED TWO AREAS OF INTEREST THAT THE NATIONAL
HURRICANE CENTER IS FOLLOWING. CURRENTLY...HURRICANE JOHN IS
LOCATED AT 15.1N AND 98.4W AT 18 UTC...SOUTH OF GUERRERO AND
OAXACA. THE PRECIPITABLE WATER LEVELS ASSOCIATED WITH THIS STORM
ARE EXPECTED TO BE HIGH AND THE SOUTHWESTERLY ONSHORE FLOW WILL
FAVOR HEAVY PRECIPITATION ALONG THE COASTS OF GUERRERO...OAXACA
OVER THE NEXT SEVERAL DAYS. THE OTHER AREA OF INTEREST IS THE
POTENTIAL TROPICAL CYCLONE NINE...LOCATED AT 17.6N AND 82.0W AT 15
UTC. THE AMOUNT OF AVAILABLE MOISTURE IS ALSO EXPECTED TO REMAIN
HIGH WITH THIS SECOND SYSTEM. PLEASE SEE THE NATIONAL HURRICANE
CENTER FOR UPDATES ON THE TROPICAL SYSTEMS.
A KEY FACTOR THAT IS FAVORING VENTILATION OVER THE PORTIONS OF
MEXICO...CENTRAL AMERICA... AND THE WESTERN CARIBBEAN IS THE
PRESENCE OF UPPER DIVERGENCE DUE TO THE PRESENCE OF AN ATMOSPHERIC
KELVIN WAVE OVER THE REGION...AS WELL AS THE PRESENCE OF THE
MADDEN-JULIAN OSCILLATION (MJO) FORECAST TO BE LOCATED IN PHASE
SEVEN...WHICH FAVOR THE UPPER DIVERGENT CONDITIONS OVER PORTIONS
OF THE AMERICAS. THESE CONDITIONS ARE EXPECTED TO REMAIN PRESENT
OVER THE NEXT SEVERAL DAYS...FAVORING DEEP CONVECTION IN SOUTHERN
MEXICO...CENTRAL AMERICA...AND THE CARIBBEAN.
OVER THE NEXT SEVERAL DAYS...HURRICANE JOHN IS EXPECTED TO
CONTINUE TO FAVOR ONSHORE FLOW INTO OAXACA...GUERRERO...AND
CHIAPAS. IT IS FORECAST TO CONTINUE A NORTHEASTERLY PATH AND ENTER
THROUGH WESTERN OAXACA BY TUESDAY EVENING INTO WEDNESDAY. IT IS
EXPECTED TO DISSIPATE ON WEDNESDAY WITH ITS ENTRANCE ALONG THE
SIERRA MADRE DEL SUR...BUT THE MOIST ONSHORE FLOW IS EXPECTED TO
CONTINUE INTO WEDNESDAY. ON MONDAY...EXPECT MAXIMA OF 75-150MM
FROM THE COASTAL REGION OF EAST GUERRERO INTO SOUTHERN OAXACA.
FROM NORTHWEST GUERRERO TO SOUTHERN VERACRUZ...EXPECT MAXIMA OF
30-60MM WITH THE BANDS EXTENDING TO THE NORTH. ON TUESDAY...THE
SYSTEM CONTINUES TO AFFECT THE SOUTHERN MEXICO REGION AND FAVOR
MAXIMA OF 100-200MM FROM EAST GUERRERO TO OAXACA. ONSHORE FLOW
ENTERING THE CHIAPAS REGION WILL FAVOR MAXIMA OF 75-150MM.
ELSEWHERE FROM CENTRAL GUERRERO...ALONG THE SIERRA MADRE
OCCIDENTAL...AND INTO NORTHERN CHIAPAS...CAN EXPECT MAXIMA OF
20-40MM. ON WEDNESDAY...THE SYSTEM IS EXPECTED TO DISSIPATE...YET
HEAVY AMOUNTS ARE STILL EXPECTED IN THE REGION. MAXIMA OF 75-150MM
ARE EXPECTED FROM EAST GUERRERO/WEST OAXACA INTO SOUTHERN
VERACRUZ. THE MOIST ONSHORE FLOW CONTINUE TO THE EAST AND WILL
FAVOR MAXIMA OF 100-200MM FROM EAST OAXACA TO CHIAPAS.
THE SECOND SYSTEM OF INTEREST IS THE POTENTIAL TROPICAL CYCLONE
NINE WHICH IS EXPECTED TO INTENSIFY OVER THE NEXT SEVERAL DAYS. ON
MONDAY...THE SYSTEM IS EXPECTED TO FAVOR PRECIPITATION OVER THE
CAYMAN ISLANDS AND JAMAICA...AS IT CONTINUES TO INTENSIFY ON
MONDAY. THE LARGE AMOUNTS OF PRECIPITABLE WATER IN THE AREA WILL
FAVOR MAXIMA OF 30-60MM IN THE CAYMAN ISLANDS AND JAMAICA. ON
TUESDAY...THE SYSTEM IS EXPECTED TO CONTINUE NORTHWARD ALONG THE
YUCATAN CHANNEL...WHERE THE SOUTHERLY LLJ WILL ASSIST WITH
MOISTURE CONVERGENCE ALONG THE WESTERN COAST OF CUBA.
SIMILARLY...THE BANDS ARE EXPECTED TO MAKE THEIR WAY INTO NORTHERN
QUINTANA ROO. AN APPROACHING UPPER LEVEL TROUGH OVER THE SOUTHERN
UNITED STATES WILL FAVOR THE A TUTT OVER THE GULF OF MEXICO TO
ENHANCE THE DEEP CONVECTION NEAR THE TROPICAL SYSTEM. ON
TUESDAY...WESTERN CUBA AND THE CAYMAN ISLANDS CAN EXPECT MAXIMA OF
50-100MM. MAXIMA OF 30-60MM ARE EXPECTED IN THE NORTHERN PORTION
OF THE YUCATAN PENINSULA. ON WEDNESDAY...THE SYSTEM CONTINUES TO
THE NORTH AND WILL FAVOR MAXIMA OF 75-150MM OVER WESTERN CUBA.
CENTRAL CUBA CAN EXPECT MAXIMA OF 20-40MM...SIMILAR AMOUNTS ARE
EXPECT OVER THE CAYMAN ISLANDS AND JAMAICA AS THE SYSTEM IS
EXPECTED TO MOVE AWAY FROM THE WESTERN CARIBBEAN.
OTHER REGIONS THAT ARE EXPECTED TO SEE HEAVY PRECIPITATION IS
SOUTHERN CENTRAL AMERICA. THE CIRCULATION ASSOCIATED WITH THE
WEAKENING CENTRAL AMERICAN GYRE CONTINUES OVER THE REGION...AND
WILL FAVOR THE CYCLONIC CIRCULATION FROM GUATEMALA...TO COSTA
RICA/WEST PANAMA. DUE TO THE INCREASED MOISTURE AND WINDS FROM THE
SOUTHWEST...FAVORABLE ONSHORE FLOW IS EXPECTED ALONG THE PACIFIC
BASIN FROM GUATEMALA...TO WEST PANAMA. ON MONDAY...EXPECT MAXIMA
OF 40-80MM FROM SOUTHERN COSTA RICA TO THE AZUERO PENINSULA IN
PANAMA. GENERALIZED MAXIMA OF 20-45MM ARE EXPECTED FROM GUATEMALA
TO THE GULF OF FONSECA REGION. ON TUESDAY...WITH THE NORTHWARD
MOVEMENT OF THE GYRE...THE MAXIMA OF 50-100MM ARE EXPECT FROM EAST
EL SALVADOR TO SOUTH CENTRAL COSTA RICA. ELSEWHERE IN CENTRAL
AMERICA EXPECT MAXIMA OF 20-40MM...ALONG THE CONTINENTAL DIVIDE.
ON WEDNESDAY...MAXIMA ARE EXPECTED TO DECREASE OVERALL DUE TO THE
CONTINUE WEAKENING OF THE CAG AND THE NORTHWARD MOVEMENT OF PCT
NINE. HOWEVER MAXIMA OF 50-100MM ARE EXPECTED FROM THE GULF OF
FONSECA AND WEST NICARAGUA. FROM GUATEMALA TO NORTH NICARAGUA
EXPECT MAXIMA TO DECREASE TO 20-35MM. YET THE PRESENCE OF THE ITCZ
OVER COSTA RICA CAN FAVOR MAXIMA OF 20-40MM.
EASTERLY/TROPICAL WAVES INITIALIZED AT 12 UTC
TYPE SOF INIT 24/00 24/12 25/00 25/12 26/00 26/12 27/00 27/12
TW 17N 47W 49W 51W 53W 55W 57W 59W 62W 65W
A TROPICAL WAVE IS INITIALIZED AT 47W AND TO THE SOUTH OF 17N. THE
WAVE IS EXPECTED TO REMAIN OVER WATER ON MONDAY AND ENTER THE
NORTHERN GUIANAS ON TUESDAY. ON TUESDAY...EXPECT TRACE AMOUNTS OF
PRECIPITATION OVER FRENCH GUIANA WITH THE PRESENCE OF DRY AIR IN
THE REGION. ON WEDNESDAY...THE WAVE IS EXPECTED OVER NORTHERN
GUYANA...WHERE EXPECT ISOLATED MAXIMA OF 15-25MM.
ACOSTA...(WPC)
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