304
FXSA20 KWBC 162007
PMDSA
SOUTH AMERICA FORECAST DISCUSSION - INTERNATIONAL DESKS
NWS WEATHER PREDICTION CENTER COLLEGE PARK MD
406 PM EDT WED OCT 16 2024
GFS DATA AT FTPPRD.NCEP.NOAA.GOV/PUB/DATA/NCCF/COM/GFS/PROD/
SOUTH AMERICAN FORECAST BULLETIN FOR 16 OCT 2024 AT 2000 UTC:
THE UPPER LEVEL CONDITIONS OVER SOUTH AMERICA ARE CONTINUING TO
SEE A PATTERN OF FAST MOVING AND PERSISTENT UPPER LEVEL TROUGHS
AND SHORTWAVE TROUGHS PROPAGATING OVER CENTRAL AND SOUTHERN SOUTH
AMERICA. ON WEDNESDAY...AN UPPER LEVEL TROUGH EXTENDS OVER THE
SOUTHERN PACIFIC OCEAN...ENTERING INTO CHILE AND ARGENTINA BY
WEDNESDAY NIGHT. THE TROUGH BECOMES A NEGATIVELY TILTED SHORTWAVE
TROUGH...WITH ITS DIVERGENT CONDITIONS OVER PORTIONS OF CENTRAL
ARGENTINA. IN THE MIDDLE LEVELS OF THE ATMOSPHERE A VERY LARGE
ADVECTION OF VORTICITY IS EXPECTED TO A FACTOR IN SEVERITY FOR THE
REGION. IN THE LOWER LEVELS...MOISTURE IS BEING ADVECTED FROM THE
LOW LEVEL JET OVER ARGENTINA...BRINGING TROPICAL MOISTURE INTO
CENTRAL PORTIONS OF ARGENTINA. THESE CONDITIONS WILL FAVOR MAXIMA
OF 20-40MM IN SOUTHERN CORDOBA AND LA PAMPA-ARGENTINA WITH AN
ELEVATED RISK OF SEVERE WEATHER...TRIGGERED BY A FRONTAL BOUNDARY
ASSISTED BY THE SHORT WAVE TROUGH ALOFT. A MARGINAL RISK OF SEVERE
WEATHER IS EXPECTED IN NORTH CORDOBA...AND RIO GRANDE AND NORTH
CHUBUT. AS THE SYSTEM QUICKLY PROGRESSES TO THE NORTH AND
EAST...EXPECT A MARGINAL RISK OF SEVERE WEATHER AND MAXIMA OD
20-35MM IN THE BORDERING REGIONS OF SANTA
FE...CHACO...CORRIENTES...AND ENTRE RIOS.
BY THURSDAY...AN INCREASE IN PRECIPITABLE WATER DUE TO THE
CONTINUED ADVECTION OF MOISTURE WILL INTO NORTH
ARGENTINA...PARAGUAY...AND SOUTH BOLIVIA...WITH ASSIST WITH HEAVY
PRECIPITATION...AS ANOTHER THE UPPER LEVEL SHORT WAVE TROUGH
PROPAGATES OVER NORTH CHILE AND INTO NORTH ARGENTINA. THIS WILL
GENERATE THE CHACO LOW WITH THE ASSISTANCE OF THE SALLJ...WHILE
MOISTURE IS CONVERGING IN THE REGION. FROM SOUTH PARAGUAY...TO
CHACO...AND SANTIAGO DEL ESTERO IN ARGENTINA...AS WELL AS...FROM
JUJUY TO NORTH CATAMARCA CAN EXPERIENCE ISOLATED MAXIMA OF
50-100MM...WITH A MODERATE RISK OF SEVERE WEATHER AND A RISK FOR
MCS FORMATION. TE DEVELOPMENT OF ANOTHER FRONTAL BOUNDARY OVER THE
REGION IS BEING ASSISTED BY THE UPPER LEVEL SHORTWAVE TROUGH AND
IS EXPECTED TO PROPAGATE NORTHWARD. TO THE EAST...THE PRESENCE OF
MOISTURE OVER CENTRAL AND EAST BRASIL BEING ADVECTED INTO THE
REGION...WITH THE PRESENCE OF SOME LOW-LEVEL TROUGHS WILL FAVOR
INCREASING AMOUNTS OF PRECIPITATION OF 20-45MM IN BRASIL. TO THE
SOUTH....SOUTHERN CHILE CAN EXPECT THE ENTRANCE OF A FRONTAL
SYSTEM WITH AN INCREASED AMOUNT OF MOISTURE...WHERE IT WILL FAVOR
MAXIMA OF 20-35MM.
BY FRIDAY...THE FAST PROGRESSION OF THE UPPER LEVEL TROUGH WILL
CONTINUE TO PUSH THE FRONTAL BOUNDARY FURTHER NORTH. THIS TROUGH
IS EXPECTED TO DISSIPATE BY FRIDAY EVENING...HOWEVER THE PRESENCE
OF A TROUGH IS EXPECTED IN THE MID LEVELS OF THE ATMOSPHERE. IN
THE LOWER LEVELS...THE CONDITIONS FOR A SACZ LIKE FEATURE IS
EXPECTED WITH THE PRESENCE OF THIS MID-LEVEL TROUGH AND THE LOWER
LEVEL WINDS CONVERGING FROM THE EAST...AND FROM THE SOUTH OVER
SOUTHERN BRASIL...INTO NORTH BOLIVIA..AND INTO SOUTHERN PERU.
THESE CONDITIONS SEEM MORE FAVORABLE INTO SATURDAY...YET THEY ARE
NOT EXPECTED TO PERSIST FOR MUCH LONGER INTO THE WEEKEND. HEAVY
LOCAL PRECIPITATION IS EXPECTED ALONG THE DEBILITATING FRONTAL
BOUNDARY FROM SOUTHERN PERU TO SOUTHEAST BRASIL...WITH MAXIMA OF
20-45MMM...AND LOCALLY HIGHER AMOUNTS ARE EXPECTED. FROM SOUTH
PARA TO NORTH MATO GROSSO...EXPECT MAXIMA OF 30-60MM...AND SIMILAR
AMOUNTS ARE EXPECTED IN EAST-CENTRAL BOLIVIA. DRIER CONDITIONS ARE
EXPECTED FROM PARAGUAY INTO ARGENTINA AND URUGUAY...EXCEPT FOR
SOUTHERN CHILE...WHICH CAN EXPECT AN ADDITIONAL FRONTAL BOUNDARY
FAVORING MAXIMA OF 20-35MM.
CASTELLANOS...(WPC)
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