548
FXCA20 KWBC 131812
PMDCA
TROPICAL DISCUSSION - INTERNATIONAL DESKS
NWS WEATHER PREDICTION CENTER COLLEGE PARK MD
211 PM EDT THU APR 13 2023
FORECAST BULLETIN FROM 13 APR 2023 AT 1700 UTC: AN UPPER TROUGH
EXTENDS ACROSS THE WESTERN USA FROM IDAHO INTO SOUTHERN
CALIFORNIA. IT IS FORECAST TO PROPAGATE EASTWARD IMPACTING
NORTHERN MEXICO...TO EXTEND ACROSS THE PLAINS OF THE USA INTO
SOUTH TEXAS/NORTHEAST TAMAULIPAS BY SATURDAY EVENING. ITS IMPACTS
IN PRECIPITATION IN MEXICO WILL BE LIMITED...GIVEN LIMITED AMOUNTS
OF AVAILABLE MOISTURE. ON THURSDAY...TOTAL PRECIPITABLE WATER
AMOUNTS WERE UNDER 30MM IN MOST OF MEXICO...WITH EXCEPTION OF THE
SOUTHERN GULF OF MEXICO REGION...WHERE A FRONTAL SHEAR LINE
STRUCTURE LIES. THIS WILL CLUSTER PRECIPITATION IN THE SIERRA
MADRE ORIENTAL...ESPECIALLY IN OAXACA AND VERACRUZ. MUCH WETTER
CONDITIONS ARE EXPECTED ON SUNDAY INTO MONDAY AS A NEW FRONT AND
ASSOCIATED NORTHEASTERLIES ENHANCE MOISTURE CONVERGENCE ALONG THE
SIERRA MADRE ORIENTAL IN SOUTHERN MEXICO. IN TERMS OF AMOUNTS...ON
THURSDAY...AMOUNTS OF 05-10MM/DAY WITH MAXIMAS OF 15-25MM ARE
EXPECTED IN THE SOUTHERN SIERRA MADRE ORIENTAL REGION. CHIAPAS AND
WESTERN GUATEMALA MAY EXPECT HIGHER AMOUNTS OF 05-10MM/DAY WITH
MAXIMAS OF 15-30MM. THE EXTREME NORTHEASTERN PORTION OF THE
YUCATAN PENINSULA MAY SEE AMOUNTS AROUND 05-10MM/DAY WITH MAXIMAS
OF 15MM. ON FRIDAY...A DECREASE IN AMOUNTS IS EXPECTED IN THE SAME
AREAS WHERE AMOUNTS EXPECTED ARE OF 00-05MM/DAY WITH MAXIMAS OF
10MM. AN INCREASE IS EXPECTED FOR SATURDAY WHERE THE SAME AREAS
AFOREMENTIONED...IN ADDITION TO TAMAULIPAS... MAY SEE GENERAL
AMOUNTS OF 05-10MM/DAY WITH MAXIMAS OF 15-20MM.
TO THE EAST...A LONG-FETCH SURFACE FRONT EXTENDS FROM THE
NORTHEAST ATLANTIC INTO 24N 57W...24N 72W...INTO NORTHEAST
FLORIDA. CYCLOGENESIS HAS OCCURRED IN THE TAIL OF THE FRONT...OVER
LOUISIANA AND MISSISSIPPI. SOUTHERLY FLOW IN THE EASTERN GULF AND
FLORIDA IS PUSHING THE FRONT NORTHEASTWARD AWAY FROM THE
BAHAMAS...RELOCATING HEAVIER PRECIPITATION IN THE EAST AND NORTH
PORTIONS OF THE ISLANDS. THE FRONT IS FORECAST TO REMAIN EAST OF
THE BAHAMAS THROUGH SATURDAY MORNING...WHEN IT IS EXPECTED TO
START LOSING DEFINITION AND EVOLVE INTO A FRONTAL SHEAR LINE.
YET...THE REMAINING MOIST PLUME WILL BE ADVECTED WESTWARD INTO THE
BAHAMAS TO FAVOR MORE PRECIPITATION ON SATURDAY AND SUNDAY
FAVORING A MAJORITY OF THE ENTIRE ISLAND CHAIN BY SUNDAY. THURSDAY
MAY BE THE DAY WITH THE MOST ACCUMULATIONS AT 10-15MM/DAY WITH
MAXIMAS OF 20-40MM IN THE NORTHERN PORTION OF THE ISLANDS.
ELSEWHERE IN THE BAHAMAS...MORE CONSERVATIVE AMOUNTS OF
05-10MM/DAY WITH MAXIMAS OF 15MM. ON FRIDAY...THE NORTHERN BAHAMAS
MAY SEE 05-10MM/DAY WITH MAXIMAS OF 15MM. AS THE SURFACE FRONT
CONTINUES TO WEAKEN ON SATURDAY... AMOUNTS ARE EXPECTED TO
DECREASE WITH CONSERVATIVE AMOUNTS OF 00-05MM/DAY WITH MAXIMAS OF
10MM FOR THE SOUTHERN BAHAMAS.
AN UPPER TROUGH IS PROPAGATING EASTWARD FROM SOUTHWEST MEXICO IN
THURSDAY INTO 85W OR EASTERN CENTRAL AMERICA BY SATURDAY EVENING.
AVAILABLE MOISTURE CONTINUES LIMITED IN THE REGION...WHICH WILL
TAMPER THE EFFECTS OF THE TROUGH IN PRECIPITATION.
HOWEVER...GRADUAL DESTABILIZATION WILL ACTIVATE DIURNAL CONVECTION
IN THE CONTINENTAL DIVIDE OF GUATEMALA...EL SALVADOR AND SOUTHWEST
HONDURAS BY SUNDAY. STILL...EXPECT CONSERVATIVE AMOUNTS. ON
THURSDAY AND FRIDAY...THE MAJORITY OF THE PRECIPITATION STAYS
NORTH IN GUATEMALA. ON SATURDAY...AMOUNTS OF 05-10MM/DAY WITH
MAXIMAS OF 15-20MM ARE EXPECTED IN SOUTHERN GUATEMALA AND EL
SALVADOR.
THE CARIBBEAN IS EXPECTED TO REMAIN UNDER THE INFLUENCE OF THE
SUBEQUATORIAL RIDGE IN THE UPPER TROPOSPHERE...AND A MID-LEVEL
RIDGE FORECAST TO ROLL FROM THE CENTRAL CARIBBEAN/NORTHERN SOUTH
AMERICA ON THURSDAY TO THE GULF OF HONDURAS AND GREATER ANTILLES
BY SUNDAY. PRECIPITABLE WATER IS VERY LOW...AS VALUES LIE IN THE
25-35MM RANGE WITH THE EXCEPTION IF PANAMA/COSTA RICA AND
HISPANIOLA/JAMAICA WHERE HIGHER VALUES ARE PRESENT. THIS WILL
LIMIT ACCUMULATIONS IN THE ENTIRE BASIN TO MAXIMA UNDER
10MM...WITH THE EXCEPTION OF HISPANIOLA...PUERTO RICO...JAMAICA
AND SOUTHEAST CUBA. FOR THURSDAY...CENTRAL PORTIONS OF HISPANIOLA
ARE EXPECTED TO RECEIVE THE HEAVIEST RAINFALL OF 10-25MM/DAY WITH
MAXIMAS OF 20-40MM. ELSEWHERE IN HISPANIOLA...PORTIONS OF
CUBA...AND PUERTO RICO ARE EXPECTED TO SEE AMOUNTS OF 05-10MM/DAY
WITH MAXIMAS OF 15MM. THE LESSER ANTILLES ARE EXPECTED TO SEE
LOWER AMOUNTS OF 00-05MM/DAY WITH MAXIMAS OF 10MM. ON
FRIDAY...SOUTHEASTERN CUBA...HAITI...AND WESTERN PUERTO RICO ARE
EXPECTED TO GENERALLY SEE AMOUNTS OF 05-10MM.DAY WITH MAXIMAS OF
15-20MM. THE CENTRAL LESSER ANTILLES MAY SEE LOWER AMOUNTS. LOWER
AMOUNTS ARE EXPECTED IN THE ARE FOR SUNDAY WITH AMOUNTS OF
05-10MM/DAY WITH MAXIMAS OF 15MM AFFECTING SMALLER PORTIONS OF THE
GREATER ANTILLES. IN THE COASTS OF COSTA RICA AND PANAMA ONSHORE
WIND FLOW WILL INTERACT WITH THE TERRAIN AND OROGRAPHIC LIFTING IS
EXPECTED TO PRODUCE RAINFALL. ON THURSDAY AND FRIDAY...05-10MM/DAY
WITH MAXIMAS OF 15-25MM ARE EXPECTED. ON SATURDAY...THE SOUTH
WESTERN COAST OF COSTA RICA IS EXPECTED TO SEE AMOUNTS OF
05-10MM/DAY WITH MAXIMAS OF 15MM.
IN SOUTH AMERICA...CONVECTION AND ASSOCIATED RAINFALL AMOUNTS
CONTINUE TO INCREASE IN THE GUIANAS IN ASSOCIATION WITH A
NORTHWARD MIGRATION OF THE ITCZ AND EASTERLY WAVE-TYPE
PERTURBATIONS MOVING IN FROM THE EAST. THIS WILL FAVOR WET
CONDITIONS IN ALL OF THE GUIANAS AND SOUTHEAST VENEZUELA THROUGH
THE WEEKEND...INCREASING TOWARDS SATURDAY AND SUNDAY. FRENCH
GUIANA...PORTIONS OF SURINAME...AND NORTHERN PARA COULD SEE
AMOUNTS OF 15-20MM/DAY WITH MAXIMAS OF 20-40MM. ELSEWHERE IN
BRAZIL AND WEST INTO SOUTHERN VENEZUELA...EASTERN COLOMBIA...AND
PERU...LOWER AMOUNTS OF 05-10MM/DAY WITH LOCALIZED MAXIMAS OF
15-25MM. ON FRIDAY...ACCUMULATIONS BEGIN TO INCREASE AS THE
PERTURBATION CONTINUES WESTWARD. EAST FRENCH GUIANA...NORTHERN
BRAZIL...AND WEST INTO SOUTHERN VENEZUELA ARE FORECAST FOR
15-20MM/DAY WITH MAXIMAS OF 20-45MM. ELSEWHERE IN THE
GUIANAS...AND SOUTHERN COLOMBIA AND PORTIONS OF NORTHWEST
BRAZIL...AND PERU...ARE FORECAST FOR 05-10MM/DAY WITH MAXIMAS OF
15-25MM. SATURDAY IS FORECAST TO HAVE HIGHER AMOUNTS OF
PRECIPITATION. THE SOUTHERN SURINAME...FRENCH GUIANA...AND
PORTIONS OF AMAPA ARE EXPECTED TO SEE 15-20MM/DAY WITH MAXIMAS OF
30-60MM. SOUTHERN VENEZUELA AND COLOMBIA...INTO NORTHERN
BRAZIL...AND EASTERN PERU MAY SEE 15-20MM/DAY WITH MAXIMAS OF
25-50MM. ELSEWHERE IN THE GUIANAS AND NORTHERN BRAZIL...AMOUNTS
EXPECTED ARE 10-15MM/DAY WITH MAXIMAS OF 20-35MM.
NORTHWEST SOUTH AMERICA WILL ALSO REMAIN ACTIVE. PRECIPITABLE
WATER REMAINS ABOVE 60MM OFF THE COAST OF WESTERN COLOMBIA AND
ECUADOR. COUPLED WITH LOW-LEVEL WESTERLIES...EXPECT ROUNDS OF
MODERATE TO LOCALLY HEAVY PRECIPITATION FROM NORTHERN PERU INTO
NORTHWEST COLOMBIA ON A DAILY BASIS. FOR THURSDAY...WESTERN
COLOMBIA AND ECUADOR COULD SEE 15-20MM/DAY WITH MAXIMAS OF
25-50MM. PORTIONS OF EXTREME NORTHWEST PERU ARE FORECAST FOR
15-20MM/DAY WITH MAXIMAS OF 35-70MM. FOR FRIDAY...A SLIGHT
DECREASE IS FORECAST FOR WESTERN COLOMBIA...EASTERN ECUADOR...AND
PORTIONS OF NORTHERN PERU...WHERE AMOUNTS ARE FORECAST FOR
15-20MM/DAY WITH MAXIMAS OF 20-45MM. WESTERN ECUADOR AND PORTIONS
OF PERU ARE FORECAST FOR HIGHER AMOUNTS OF 15-20MM/DAY WITH
MAXIMAS OF 40-80MM. FOR SATURDAY...HIGH AMOUNTS OF PRECIPITATION
ARE PERSISTENT FOR WESTERN PORTIONS OF COLOMBIA...ECUADOR...AND
PERU. SOUTHWESTERN COLOMBIA AND WESTERN ECUADOR ARE FORECAST FOR
15-20MM/DAY WITH MAXIMAS OF 35-70MM. WHILE EXTREME NORTHWESTERN
PERU COULD SEE HIGHER AMOUNTS OF 20-40MM/DAY WITH MAXIMAS OF
50-100MM. ELSEWHERE IN COLOMBIA...EASTERN ECUADOR...AND
PERU...AMOUNTS ARE GENERALLY EXPECTED AT 10-15MM/DAY WITH MAXIMAS
OF 20-45MM/DAY.
GALVEZ/ALAMO/ACOSTA...WPC (USA)
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