THE WEATHER PREDICTION CENTER

COLLEGE PARK, MD


SOUTH AMERICAN SYNOPSIS




SOUTH AMERICA SYNOPTIC DISCUSSION - INTERNATIONAL DESKS
NWS WEATHER PREDICTION CENTER COLLEGE PARK MD
857 AM EDT MON JUL 24 2017

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

SYNOPSIS (VALID FROM JUL 24 AT 0000 UTC): AT 200 HPA...THE UPPER
LEVEL ANALYSIS SHOWS A BROAD/LOW AMPLITUDE RIDGE OVER THE
CONTINENT ENVELOPING AREA NORTH OF 10S. BROAD TROUGH LIES TO THE
EAST... EXTENDING TO THE NORTHWEST ALONG 30S 30W...23S 40S TO
SANTA CRUZ IN EASTERN BOLIVIA. THE RIDGE ALOFT IS VENTING DIURNAL
CONVECTION ACROSS THE GUIANAS-NORTHERN PARA-AMAZONAS/RORAIMA IN
BRASIL... VENEZUELA-COLOMBIA AND THE NORTHERN JUNGLE OF PERU.

AT 250 HPA...THE SOUTHERN POLAR LIES ALONG A 135KT MAXIMUM AT 53S
118W...52S 103W...EXITING AT 45S 84W. IT REFORMS AT 43S 90W...THEN
ALONG 41S 84W...42S 72W...46S 50W...49S 36W...A 124KT MAXIMUM AT
45S 19W...41S 07W...AND 44S 02E. THE NORTHERN POLAR HAS ITS
ENTRANCE AT 32S 92W...THEN ALONG 37S 73W...40S 61W...A 152KT
MAXIMUM AT 43S 46W...43S 30W...EXITING AT 37S 18W. THE SUBTROPICAL
JET HAS ITS ENTRANCE AT 30S 122W...THEN ALONG A 138KT MAXIMUM AT
26S 105W...A 137KT MAXIMUM AT 28S 92W...31S 80W...A 163KT MAXIMUM
AT 33S 70W...36S 55W...EXITING AT 35S 41W. A BRANCH OF THE
SUBTROPICAL TO THE NORTH LIES ALONG 19S 120W...23S 106W...25S
89W...26S 78W...EXITING AT 27S 66W.

AT 500 HPA...A BROAD MID LEVEL TROUGH DOMINATES THE FLOW OVER THE
EASTERN PACIFIC...ENVELOPING AREA BETWEEN 120W-70W AND TO THE
SOUTH OF 20S. THIS IS FOCUSING SHORT WAVE ENERGY ACROSS SOUTHERN
CHILE INTO PATAGONIA IN ARGENTINA. FARTHER EAST...A PROGRESSIVE
SHORT WAVE TROUGH IS PULLING ACROSS 45W WHILE CLASHING AGAINST A
RIDGE TO THE EAST. THE RIDGE EXTENDS FROM 33S 35W...ALONG 50S
34W...60S 42W...TO THE ANTARCTIC PENINSULA.

AT LOW LEVELS...BROAD TROUGH DOMINATES THE FLOW OVER THE SOUTHEAST
PACIFIC. POLAR FRONTS REVOLVE AROUND THIS AXIS...WITH ONE
EXTENDING FROM AN OCCLUDED 962 HPA LOW AT 62S 110W...A 968 HPA LOW
AT 63S 112W...A 964 HPA LOW AT 60S 98W...A 966 HPA LOW AT 56S
91W...A 972 HPA LOW AT 54S 81W...51S 75W...A 994 HPA LOW AT 45S
78W...38S 80W...A 1018 HPA LOW AT 35S 98W...AND 30S 102W. THIS
SUSTAINS ISOLATED TO SCATTERED CONVECTION ACROSS SOUTHERN CHILE.
FARTHER EAST...AN OCCLUDED 978 HPA LOW CENTERS AT 57S 60W. AN
ELONGATED POLAR FRONT TO THE NORTHEAST OF THIS LOW ORIGINATES ON A
986 HPA LOW AT 50S 45W...THEN ALONG A 996 HPA LOW AT 48S 40W...A
1008 HPA LOW AT 44S 39W...A 1010 HPA LOW AT 39S 48W...35S 52W...A
1010 HPA LOW AT 33S 59W...30S 66W...A 1022 HPA LOW AT 32S
70W...28S 78W...AND 25S 88W. A RIDGE TO THE SOUTH CENTERS ON A
1025 HPA HIGH AT 35S 72W AND A 1019 HPA HIGH AT 36S 65W. OVER THE
ATLANTIC...A RIDGE TO THE NORTH CENTERS ON A 1033 HPA HIGH AT 33S
26W.

ESPINOLA...DNM (PARAGUAY)
GONZALEZ...DMC (CHILE)
DAVISON/GALVEZ...WPC (USA)




Last Updated: 857 AM EDT MON JUL 24 2017