243
FXCA20 KWBC 191711
PMDCA
TROPICAL DISCUSSION - INTERNATIONAL DESKS
NWS WEATHER PREDICTION CENTER COLLEGE PARK MD
110 PM EDT FRI MAY 19 2023
NOTE: THERE IS A RISK FOR HEAVY RAINFALL IN NORTHWEST SOUTH
AMERICA AND ALSO IN HISPANIOLA AND PUERTO RICO...IN ASSOCIATION
WITH A POTENT UPPER TROUGH DEEPENING ACROSS THE CARIBBEAN. DUE TO
ENHANCEMENT BY A TROPOSPHERIC KELVIN WAVE AND HIGH VALUES OF
AVAILABLE MOISTURE...EXPECT PERIODS WITH EXCESSIVE RAINFALL
BETWEEN FRIDAY AND MIDDAY MONDAY.
FORECAST BULLETIN FROM 19 MAY 2023 AT 1700 UTC: A CLOSED UPPER LOW
IN NORTHWEST MEXICO IS INTERACTING WITH A MID-UPPER RIDGE TO ITS
SOUTHEAST. THIS IS FAVORING A CORRIDOR OF WHERE UPPER DIVERGENCE
WILL BE ENHANCED INTERMITTENTLY ACROSS CENTRAL INTO NORTHWEST
MEXICO ESPECIALLY ON FRIDAY AND SATURDAY. A SHORT WAVE TROUGH IS
FORECAST TO PROPAGATE FROM SOUTHWEST TO NORTHEAST ON SATURDAY...TO
PROVIDE ADDITIONAL ENHANCEMENT TO DIURNAL CONVECTION AND FAVOR
MODERATE TO LOCALLY HEAVY RAINFALL. ON FRIDAY EXPECT 05-10MM/DAY
AND ISOLATED MAXIMA OF 15-30MM IN NORTHERN COAHUILA AND ALONG
EASTERN PARTS OF THE MEXICAN PLATEAU. A PEAK IS EXPECTED ON
SATURDAY WHEN AMOUNTS ARE LIKELY TO REACH 15-20MM/DAY AND MAXIMA
OF 35-70MM FROM SAN LUIS POTOSI NORTH INTO THE RIO BRAVO. WEST
ACROSS THE CENTRAL MEXICAN PLATEAU INTO COAHUILA EXPECT
10-15MM/DAY AND MAXIMA OF 20-45MM...WHILE IN WESTERN AND
SOUTHWESTERN MEXICO EXPECT 05-10MM/DAY AND ISOLATED MAXIMA OF
15-25MM. ACCUMULATIONS ARE EXPECTED TO DECREASE THEREAFTER AS THE
MID-UPPER FLOW ACQUIRES A MORE WESTERLY COMPONENT ADVECTING A
DRIER AIR MASS INTO CENTRAL AND NORTHERN MEXICO.
QUIET CONDITIONS ARE EXPECTED IN MOST OF CENTRAL AMERICA AS THE
REGION IS EXPECTED TO LIE UNDER THE INFLUENCE OF A MID-LEVEL RIDGE
AND IN A BROAD REGION WITH LIMITED AVAILABLE MOISTURE ADVECTED
FROM THE NORTH AND NORTHEAST. ASIDE FROM EASTERN PANAMA...EXPECT
VERY LIMITED COVERAGE OF DIURNAL CONVECTION AND LIGHT RAINFALL
ACCUMULATIONS THROUGH THE WEEKEND.
OF SIGNIFICANCE IS A ROBUST UPPER TROUGH THAT IS DEEPENING ACROSS
THE EASTERN GULF OF MEXICO/NORTHWEST FLORIDA/BAHAMAS ON FRIDAY. AS
A ROBUST UPPER RIDGE BUILDS OVER THE EASTERN PACIFIC AND
MEXICO...EXPECT ENHANCED NORTHERLY WINDS IN THE UPPER LEVELS TO
STIMULATE THE AMPLIFICATION OF THE UPPER TROUGH INTO NORTHERN
SOUTH AMERICA BY SUNDAY. THIS WILL PROVIDE A FORMIDABLE REGION OF
UPPER DIVERGENCE IN THE GULF OF PANAMA AND EXTREME NORTHERN
COLOMBIA DURING LATE SATURDAY/SUNDAY...EXTENDING INTO NORTHWEST
AND NORTH-CENTRAL VENEZUELA BY MONDAY. HIGH VALUES OF PRECIPITABLE
WATER ARE ALREADY IN PLACE. THIS...IN COMBINATION WITH THE UPPER
TROUGH AND THE ARRIVING KELVIN WAVE WILL FAVOR PERIODS OF HEAVY
RAINFALL IN WESTERN COLOMBIA/EASTERN PANAMA THROUGH THE
WEEKEND...SPREADING INTO NORTHWEST AND NORTH-CENTRAL VENEZUELA BY
SUNDAY/MONDAY AND POSSIBLY INTO TUESDAY. THE SYSTEM WILL ALSO
ENHANCE PRECIPITATION IN HISPANIOLA AND PUERTO RICO...WHERE A
MOIST PLUME IS IN PLACE. ALTHOUGH MOST OF THE FORCING IS EXPECTED
NORTH OF THE ISLANDS...SHORT WAVE VORTICES EMBEDDED IN THE MAIN
UPPER TROUGH WILL HIGHLIGHT ASCENT LOCALLY TO STIMULATE CONVECTION
AND DEVELOP LOCALLY HEAVY AMOUNTS ESPECIALLY IN THE DOMINICAN
REPUBLIC.
IN TERMS OF ACCUMULATIONS FOR NORTHERN SOUTH AMERICA/EASTERN
PANAMA...ON FRIDAY...EXPECT 25-50MM/DAY AND MAXIMA OF 75-125MM
FROM THE SOUTHERN CHOCO INTO SOUTHWEST COLOMBIA...AND 15-20MM/DAY
WITH MAXIMA OF 25-50MM FROM THE DARIEN/EASTERN PANAMA INTO THE
MAGDALENA MEDIO AND SANTANDER. MODERATE AMOUNTS ARE EXPECTED ALSO
ALONG THE NET FROM SOUTH-CENTRAL VENEZUELA INTO THE COLOMBIAN
ORINOQUIA WHERE EXPECT MAXIMA OF 20-45MM. ON SATURDAY...EXPECT THE
HEAVIEST FROM THE CHOCO AND ANTIOQUIA IN NORTHWEST COLOMBIA TO
EASTERN PANAMA. HERE...EXPECT 25-50MM/DAY AND MAXIMA OF 75-125MM
WITH A RISK FOR MCS. IN NORTHERN COLOMBIA INTO THE LAKE MARACAIBO
EXPECT 15-30MM/DAY AND MAXIMA OF 40-80MM. CONVECTION ALONG THE NET
WILL ALSO FAVOR MAXIMA OF 20-45MM FROM SOUTHEAST VENEZUELA ACROSS
THE ORINOQUIA INTO CENTRAL COLOMBIA. ON SUNDAY THROUGH EARLY
MONDAY...EXPECT THE HEAVIEST STILL ACROSS NORTHWEST
COLOMBIA/EASTERN PANAMA WHERE AMOUNTS ARE FORECAST TO REACH
25-50MM/DAY AND MAXIMA OF 75-125MM. IN NORTHERN COLOMBIA AND
NORTHWEST AND NORTH-CENTRAL VENEZUELA EXPECT 15-20MM/DAY AND
MAXIMA OF 40-80MM.
IN TERMS OF AMOUNTS FOR THE GREATER ANTILLES AND BAHAMAS...ON
FRIDAY EXPECT 05-10MM/DAY AND MAXIMA OF 15-30MM FROM SOUTHEAST
CUBA INTO MOST OF THE BAHAMAS. IN HISPANIOLA EXPECT 15-20MM/DAY
AND ISOLATED MAXIMA OF 25-50MM...WHILE IN PUERTO RICO EXPECT
MAXIMA OF 20-45MM. ON SATURDAY...EXPECT AMOUNTS INCREASING TO
25-50MM/DAY AND MAXIMA OF 75-125MM IN HISPANIOLA...WHILE IN
NORTHWEST PUERTO RICO EXPECT ISOLATED MAXIMA OF 30-60MM. IN THE
SOUTHEAST BAHAMAS/TURKS AND CAICOS EXPECT MAXIMA OF
20-45MM...WHILE IN JAMAICA EXPECT MAXIMA OF 15-25MM. ON
SUNDAY...EXPECT 20-40MM/DAY AND MAXIMA OF 50-100MM IN HISPANIOLA
WITH A RISK FOR MCS FORMATION...WHILE IN PUERTO RICO EXPECT MAXIMA
OF 25-50MM.
POSITIONS OF TROPICAL/EASTERLY WAVES INITIALIZED AT 12 UTC
TYPE SOF INIT 20/00 20/12 21/00 21/12 22/00 22/12 23/00
EW 11N 63W 66W 68W 71W 72W 73W DISS
TW 14N 78W 79W DISS
AN EASTERLY WAVE IS INITIALIZED AT 63W AND SOUTH OF 11N. THE WAVE
IS FORECAST TO START SLOWING DOWN ON SATURDAY...AS IT STARTS
INTERACTING WITH THE UPPER TROUGH IN THE CARIBBEAN...TO BECOME
ABSORBED BY THE INDUCED TROUGH BY MONDAY.
A TROPICAL WAVE IS INITIALIZED AT 78W AND TO THE SOUTH OF 14N.
HOWEVER...IT IS RAPIDLY LOSING DEFINITION AS THE PANAMANIAN LOW
CIRCULATION GAINS STRENGTH BECOMING DOMINANT IN THE MODULATION OF
CONVECTION IN WESTERN COLOMBIA. THE WAVE IS FORECAST TO DISSIPATE
BEFORE SUNRISE ON SATURDAY.
GALVEZ/ACOSTA...WPC (USA)
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