SOUTH AMERICA SYNOPTIC DISCUSSION - INTERNATIONAL DESKS
NWS WEATHER PREDICTION CENTER COLLEGE PARK MD
956 AM EDT TUE MAY 14 2013

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

SYNOPSIS (VALID FROM 00 UTC MAY 14): THE 200 HPA ANALYSIS SHOWS A
LOW AMPLITUDE RIDGE ACROSS NORTHERN SOUTH AMERICA...WITH AXIS
ENVELOPING AREA TO THE NORTH OF 30S. A SHORT WAVE TROUGH TO THE
EAST EXTENDS TO THE NORTH-NORTHWEST ALONG 20S 30W TO RIO GRANDE DO
NORTE IN BRASIL. SATELLITE IMAGERY SHOWS SCATTERED DEEP CONVECTION
ACROSS SOUTHERN AMAZONAS-ACRE IN WESTERN BRASIL TO THE NORTHERN
JUNGLE OF PERU. OTHER ACTIVITY WAS BUILDING NORTH OF THE EQUATOR
ALONG THE NEAR EQUATORIAL TROUGH.

THE 250 HPA JET ANALYSIS SHOWS THE SOUTHERN POLAR WITH AXIS ALONG
70S 86W...A 135KT MAXIMUM AT 60S 76W...A 128KT MAXIMUM AT 50S
80W...43S 74W...41S 66W...46S 50W...49S 40W...54S 31W...AND 54S
17W. THE NORTHERN POLAR HAS A FINGER THAT EXTENDS BETWEEN 59S 89W
AND 46S 87W. IT HAS ANOTHER FINGER THAT EXTENDS BETWEEN 36S 83W
AND 34S 65W. THE JET REFORMS AT 36S 56W...ALONG 42S 40W...46S
22W...EXITING AT 42S 08W. THE SUBTROPICAL JET HAS ITS ENTRANCE AT
27S 88W...ALONG 27S 74W...27S 60W...28S 55W...30S 49W...EXITING AT
30S 42W.

AT 500 HPA...MID LEVEL ANALYSIS SHOWS A LONG WAVE RIDGE WITH AXIS
SOUTH ALONG 95W TO THE POLAR ICE CAP. THIS RIDGE IS DIVERTING COLD
POLAR AIR INTO THE BACKSIDE OF A LONG WAVE TROUGH OVER THE
CONTINENT. TROUGH ENVELOPS AREA BETWEEN 80W-40W AND TO THE SOUTH
OF 25S...WHILE FOCUSING ITS SHORT WAVE ENERGY ACROSS SOUTHERN
CHILE TO PATAGONIA IN ARGENTINA. THIS IS TRIGGERING SNOW SHOWERS
ACROSS TIERRA DEL FUEGO AND EXTREME SOUTHERN PORTIONS OF CHILE.

AT LOW LEVELS...THE SURFACE ANALYSIS SHOWS BROAD RIDGE ACROSS THE
EASTERN PACIFIC...CENTERING ON A 1033 HPA HIGH AT 44S 92W. A
TROUGH LIES TO THE EAST...AS IT EXPANDS FROM THE WEDDELL SEA TO
THE SOUTHERN CONE OF SOUTH AMERICA. THE TROUGH ANCHORS ON AN
OCCLUDED 970 HPA LOW AT 61S 43W. POLAR FRONTS REVOLVE AROUND THIS
AXIS...WITH ONE ALONG A 980 HPA LOW AT 57S 36W...51S 37W...45S
43W...40S 50W...A 1006 HPA LOW AT 43S 61W...LA PAMPA IN
ARGENTINA...CONCEPCION CHILE...36S 79W...AND 40S 87W. A SECONDARY
FRONT FOLLOWS...AS IT EXTENDS ALONG A 1008 HPA LOW AT 46S
66W...NORTHERN PATAGONIA... TEMUCO CHILE...40S 81W...TO 43S 86W.
AN OLD FRONT TO THE NORTH LIES ALONG A 1014 HPA LOW AT 42S
32W...38S 37W...34S 45W...29S 53W...TO NORTHWEST PROVINCES IN
ARGENTINA. ORGANIZED DEEP CONVECTION WAS BUILDING NORTH OF THIS
BOUNDARY ACROSS PARAGUAY TO SOUTHERN BRASIL. A RIDGE ON THE
NORTHERN STREAM LIES TO THE EAST...CENTERING ON A 1029 HPA HIGH AT
32S 19W.

MAQUEDA...DINAC (PARAGUAY)
SILVA DE SOUZA...INMET (BRASIL)
DAVISON...WPC (USA)
GALVEZ...WPC (USA)