THE WEATHER PREDICTION CENTER

COLLEGE PARK, MD


SOUTH AMERICAN SYNOPSIS




SOUTH AMERICA SYNOPTIC DISCUSSION - INTERNATIONAL DESKS
NWS WEATHER PREDICTION CENTER COLLEGE PARK MD
838 AM EDT FRI MAY 26 2017

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

LAST NO AMENDS...NEXT BULLETIN MAY 30.

SYNOPSIS (VALID FROM MAY 26 AT 0000 UTC): AT 200 HPA...A LONG WAVE
RIDGE EXTENDS TO THE SOUTHEAST FROM SOUTHERN COLOMBIA/NORTHERN
PERU...ACROSS BRASIL ALONG 20S 50W...INTO THE ATLANTIC ALONG 30S
40W TO 44S 25W. THE LONG WAVE RIDGE UNDERCUTS A TROUGH TO THE
EAST. THE TROUGH EXTENDS ALONG 30S 25W...20S 30W...10S 37W...TO
NORTHEAST STATES OF BRASIL. THE TROUGH IS ENHANCING CONVECTIVE
DEVELOPMENT OVER NORTHEAST STATES OF BRASIL...WHILE THE RIDGE
ALOFT WAS VENTING WIDELY ISOLATED CONVECTION ACROSS
PARA-AMAZONAS-ACRE IN BRASIL...THE PERUVIAN JUNGLE AND PORTIONS OF
BOLIVIA.

THE 250 HPA ANALYSIS SHOWS THE SOUTHERN POLAR WITH AXIS ALONG 72S
91W...65S 78W...A 136KT MAXIMUM AT 58S 72W...46S 62W...50S
45W...55S 31W...AND 56S 14W. THE NORTHERN POLAR HAS ITS ENTRANCE
AT 42S 85W... ALONG 35S 84W...EXITING AT 28S 83W. IT REFORMS AT
26S 78W...THEN ALONG 31S 70W...36S 61W...A 139KT MAXIMUM AT 40S
50W...A 193KT MAXIMUM AT 47S 37W...A 135KT MAXIMUM AT 49S
26W...48S 14W...AND 49S 01W. THE SUBTROPICAL JET HAS ITS ENTRANCE
AT 18S 93W...THEN ALONG 18S 86W...A 144KT MAXIMUM AT 19S 80W...A
159KT MAXIMUM AT 28S 69W...A 159KT MAXIMUM AT 34S 57W...38S
46W...38S 37W...EXITING AT 37S 32W. ANOTHER BRANCH TO THE NORTH
HAS ITS ENTRANCE AT 16S 110W...THEN ALONG 15S 96W...17S 76W...23S
66W...28S 57W...EXITING AT 30S 46W.

AT 500 HPA...A SKEWED LONG WAVE RIDGE EXTENDS ALONG 30S 100W...45S
85W...60S 90W...TO 70S 100W. DOWNSTREAM FROM THIS AXIS...A TROUGH
IS AMPLIFYING ACROSS THE WEDDELL SEA/THE MALVINAS TO PATAGONIA IN
ARGENTINA. A SHORT WAVE TROUGH ON THE NORTHERN STREAM TRAILS THIS
PERTURBATION. THE NORTHERN STREAM VORTEX ANCHORS ON A CLOSED LOW
NEAR 30S 80W AND EXTENDS A TROUGH TO 19S 90W. THIS IS FOCUSING
SHORT WAVE ENERGY ACROSS NORTHERN CHILE/ARGENTINA...PROVIDING
DYNAMICAL SUPPORT TO ORGANIZED DEEP CONVECTION ACROSS SOUTHERN
BRASIL-MESOPOTAMIA VALLEY IN ARGENTINA.

AT LOW LEVELS...THE SURFACE ANALYSIS SHOWS A RIDGE OVER THE FAR
EASTERN PACIFIC THAT CENTERS ON A 1029 HPA HIGH AT 39S 89W. BROAD
TROUGH ON THE SOUTHERN STREAM LIES TO THE EAST...WITH AN OCCLUDED
978 HPA LOW AT 53S 53W. THIS EXTENDS A FRONT ALONG A 974 HPA LOW
AT 57S 44W...A 974 HPA LOW AT 58S 37W...56S 34W...55S 39W...A 982
HPA LOW AT 52S 43W...49S 44W...A 998 HPA LOW AT 47S 52W...45S
58W...TO 45S 67W. ANOTHER FRONT LIES TO THE NORTH...WITH AXIS
ALONG 46S 26W...45S 31W...A 1006 HPA LOW AT 45S 36W...41S 37W...A
1006 HPA LOW AT 38S 45W...36S 49W...A 1006 HPA LOW AT 35S
51W...RIO GRANDE DO SUL...CORRIENTES ARGENTINA TO JUJUY/SALTA TO
THE NORTHWEST. THIS FAVORS ORGANIZED CONVECTION ACROSS SOUTHERN
BRASIL-MESOPOTAMIA VALLEY IN ARGENTINA. A RIDGE TO THE EAST
ANCHORS ON A 1033 HPA HIGH AT 36S 15W. AN OLD/ELONGATED FRONT TO
THE NORTH LIES ALONG 12S 11W...11S 20W...11S 29W...TO NORTHEAST
BRASIL. THIS IS ENHANCING LOW LEVEL MOISTURE CONVERGENCE WHILE
FAVORING MODERATE TO HEAVY CONVECTION.

ABDEMUR...FAA (ARGENTINA)
ESPINOLA...DNM (PARAGUAY)
DAVISON...WPC (USA)




Last Updated: 838 AM EDT FRI MAY 26 2017