822
FXSA20 KWBC 141907
PMDSA
SOUTH AMERICA FORECAST DISCUSSION - INTERNATIONAL DESKS
NWS WEATHER PREDICTION CENTER COLLEGE PARK MD
307 PM EDT FRI JUN 14 2024
GFS DATA AT FTPPRD.NCEP.NOAA.GOV/PUB/DATA/NCCF/COM/GFS/PROD/
SOUTH AMERICAN DISCUSSION FOR 14-JUNE 2024 AT 18 UTC:
A POTENT UPPER TROUGH IS CROSSING THE ANDES AFTER FAVORING EXTREME
PRECIPITATION IN CENTRAL CHILE. AS THE TROUGH CROSSES THE
ANDES...REMAINING PRECIPITATION AND POST-FRONTAL COLD AIR
CONVECTION WILL FAVOR ADDITIONAL ACCUMULATION OF 10-15MM/DAY AND
ISOLATED MAXIMA OF 20-45MM IN INTERIOR PORTIONS OF CENTRAL CHILE
AND BETWEEN CURICO AND ARAUCANIA. EXPECT A DECREASE IN
ACCUMULATION ON SATURDAY.
THE UPPER TROUGH CROSSING THE ANDES IS LOSING AMPLITUDE.
HOWEVER...IT IS INTERACTING WITH A MOIST AIR MASS LOCATED ALONG
THE RIO DE LA PLATA ON FRIDAY AFTERNOON. UPPER JET DYNAMICS ARE
PRESENT...WHICH WILL STIMULATE THE VERTICAL DEVELOPMENT OF
CONVECTION. HOWEVER...VERTICAL WIND SHEAR AND ACCELERATED STORM
MOTION IS LIMITING POTENTIAL RAINFALL ACCUMULATIONS IN THE RIO DE
LA PLATA/URUGUAY ON FRIDAY. EXPECT AMOUNTS OF 05-10MM/DAY AND
MAXIMA OF 15-30MM CLUSTERING MOSTLY IN URUGUAY...AND LESSER
AMOUNTS IN THE NORTHERN BUENOS AIRES PROVINCE. EXPECT ALSO A
MODERATE RISK FOR SEVERE CONVECTION. ON SATURDAY...EXPECT THE COLD
FRONT TO BECOME STATIONARY ACROSS SOUTHERN BRASIL WHILE EXTENDING
INTO FORMOSA AND THE CHACO PARAGIAYO/SOUTHERN BOLIVIA. ENHANCED
MOISTURE CONVERGENCE ALONG THE FRONT WILL INTERACT WITH UPPER JET
DYNAMICS TO FAVOR LARGER ACCUMULATION. FURTHERMORE...PERSISTENT
INFLUENCE OF THE SOUTH AMERICAN LOW-LEVEL JET AND DEVELOPING
ISENTROPIC LIFT WILL FAVOR ENHANCED LOW-LEVEL MOISTURE CONVERGENCE
TO FAVOR HEAVIER RAINFALL AMOUNTS. EXPECT 15-30MM/DAY AND MAXIMA
OF 40-80MM EXTENDING FROM NORTHERN CORRIENTES INTO RIO GRANDE DO
SUL. THIS INCLUDES A MARGINAL RISK FOR SEVERE CONVECTION. ON
SUNDAY...EXPECT AN INCREASE IN ISENTROPIC LIFT...WHICH WILL FAVOR
HEAVIER PRECIPITATION DEVELOPING OVER THE POST-FRONTAL AIR MASS IN
SOUTHERN/SOUTHEAST PARAGUAY...MISIONES...INTO PARANA/SANTA
CATARINA IN BRASIL. EXPECT AMOUNTS OF 20-40MM/DAY AND MAXIMA OF
50-100MM WITH A MARGINAL RISK OF SEVERE CONVECTION.
ALSO IN SOUTHERN SOUTH AMERICA...TEMPERATURES ARE EXPECTED TO
REMAIN COLD ENOUGH FOR PERSISTENT SNOW SHOWERS TO THE SOUTH OF
50-52S. YET...EXPECT LIGHT ACCUMULATIONS TO GENERALLY REMAIN IN
THE 05-10CM/DAY RANGE FOR WESTERN AND SOUTHERN SLOPES OF TIERRA
DEL FUEGO.
IN TROPICAL REGIONS OF SOUTH AMERICA...A MOIST PLUME IR ORGANIZING
IN THE TROPICAL MOIST ATLANTIC JUST TO THE EAST OF NORTHEAST
BRASIL. A SHEAR-LINE LIKE STRUCTURE IS ORGANIZING...WHICH IS
HIGHLIGHTING MOISTURE CONVERGENCE AND ACCUMULATION IN COASTAL
REGIONS OF NORTHEAST BRASIL. ON FRIDAY EXPECT MAXIMA IN THE
15-30MM/DAY RANGE. THIS INCREASES TO MAXIMA OF 25-50MM BY SATURDAY
THROUGH EARLY SUNDAY...DECREASING TO MAXIMA OF 15-25MM/DAY ON
SUNDAY.
LASTLY...MOIST EASTERLY FLOW IN A REGION OF ABOVE-AVERAGE
PRECIPITABLE WATER CONTINUES TO FAVOR AN UNSEASONABLY MOIST
WEATHER PATTERN IN NORTHERN PERU AND ECUADOR. FURTHERMORE...THE
SOUTHERN TAIL OF A TROPICAL WAVE IS ENHANCING PRECIPITATION.
THROUGH EARLY SATURDAY EXPECT 10-15MM/DAY AND ISOLATED MAXIMA OF
20-35MM. AS THE MOIST PLUME REACHES THE ANDES...THIS INCREASES TO
MAXIMA OF 20-45MM ON SATURDAY THROUGH EARLY SUNDAY...DECREASING
THEREAFTER.
GALVEZ (WPC)
PALAVECINO (SMN-ARGENTINA)
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