THE WEATHER PREDICTION CENTER

COLLEGE PARK, MD


SOUTH AMERICAN SYNOPSIS




SOUTH AMERICA SYNOPTIC DISCUSSION - INTERNATIONAL DESKS
NWS WEATHER PREDICTION CENTER COLLEGE PARK MD
931 AM EDT FRI APR 24 2015

GFS DATA AT FTPPRD.NCEP.NOAA.GOV/PUB/DATA/NCCF/COM/GFS/PROD/

SYNOPSIS (VALID FROM APRIL 24 AT 00UTC): AT 200 HPA...THE UPPER
FLOW SPLITS BETWEEN THE SUBEQUATORIAL AND SUBTROPICAL
RIDGES...WITH THE SUBEQUATORIAL RIDGE EXTENDING WEST ACROSS THE
TROPICAL ATLANTIC TO THE GUIANAS-VENEZUELA-COLOMBIA WHILE
ANCHORING ON A CLOSED HIGH NEAR 02N 37W. THE SUBTROPICAL RIDGE TO
THE SOUTH DOMINATES CONTINENTAL AREA BETWEEN 00N-30S...WHILE
CENTERING ON A CLOSED HIGH NEAR 15S 52W. DIVERGENCE BETWEEN THESE
RIDGES IS VENTING ORGANIZED DEEP CONVECTION ALONG THE NORTH COAST
OF BRASIL INTO NORTHERN PARA-AMAZONAS TO THE WEST. THE SUBTROPICAL
RIDGE IS ALSO VENTING DIURNAL CONVECTION ACROSS CENTRAL PORTIONS
OF BRASIL-NORTHERN BOLIVIA TO PERU.

THE 250 HPA JET ANALYSIS SHOWS THE SOUTHERN POLAR JET FORMING AT
59S 100W ALONG 62S 84W...59S 65W...54S 54W...53S 36W...53S 15W.
THE NORTHERN POLAR JET FORMS AT 33S 105W ALONG A 144KT MAXIMA AT
39S 97W...A 146KT MAXIMA AT 46S 87W...A 173 MAXIMA AT 51S 64W...A
148KT MAXIMA AT 49S 41W...EXITING AT 43S 19W. THE SUBTROPICAL JET
FORMS AT 23S 109W ALONG 37S 94W...44S 75W...46S 56W...EXITING AT
43S 40W. ANOTHER BRANCH FORMS AT 23S 77W ALONG 28S 63W...A 129KT
MAXIMA OVER PORTO ALEGRE...28S 35W...30S 19W...35S 06W.

AT 500 HPA...A LONG WAVE TROUGH ON THE NORTHERN STREAM EXTENDS
FROM A CLOSED LOW NEAR 45S 102W...ALONG 35S 103W...TO 23S 110W.
THIS IS PRESSING AGAINST A RIDGE TO THE EAST THAT EXTENDS FROM 36S
78W... ALONG THE SOUTH COAST OF CHILE TO THE BELLINGSHAUSEN SEA.
IN A TIGHT GRADIENT BETWEEN THESE SYSTEMS...SHORT WAVE ENERGY AND
SUBTROPICAL MOISTURE FOCUSES ACROSS SOUTHERN PORTIONS OF CHILE.
FARTHER EAST... OVER THE SOUTH ATLANTIC...A BROAD/LOW AMPLITUDE
TROUGH EXTENDS BETWEEN 65W-00W AND TO THE SOUTH OF 40S. SHORT WAVE
PERTURBATIONS POPULATE THE NORTHERN STREAM FLOW ACROSS MID
SECTIONS OF SOUTH AMERICA AND THE EASTERN PACIFIC. THE WESTERNMOST
CENTERS ON A CLOSED LOW NEAR 26S 82W...WHILE TWO OTHERS TO THE
EAST EXTEND OVER CORDOBA IN ARGENTINA AND EASTERN URUGUAY/RIO
GRANDE DO SUL IN BRASIL.

THE SURFACE ANALYSIS SHOWS A 986 HPA LOW AT 50S 41W EXTENDING A
FRINT INTO 46S 55W...48S 70W...A 1002 HPA LOW AT 49S 80W...46S
81W...A 1006 HPA LOW AT 44S 89W...37S 93W. RAINFALL WAS BEING
REPORTED OVER SOUTHERN PATAGONIA. A 1003 HPA POLAR HIGH CENTERS AT
53S 78W. A 1021 HPA HIGH CENTERS AT 34S 82W. THIS HIGH RIDGES INTO
TWO 1017 HPA HIGHS. ONE CENTERS AT 29S 90W AND ANOTHER AT 40S 74W.
TO THE EAST...A 1014 HPA LOW AT 35S 09W EXTENDS A FRONT INTO 28S
18W...25S 28W...A 1014 HPA LOW AT 22S 33W...20S 38W...24S 44W...A
1014 HPA LOW AT 27S 53W...24S 56W...23S 60W. TWO THE SOUTH OF THIS
FRONT...TWO 1023 HPA HIGHS CENTER AT 30S 36W...AND AT 34S 52W.

CALLE...UNALM (PERU)
CHARPENTIER...DMC (CHILE)
SCHNEIDER...INMET (BRASIL)
DAVISON...WPC (USA)
GALVEZ...WPC (USA)





Last Updated: 931 AM EDT FRI APR 24 2015