Prognostic Meteorological Discussion
Issued by NWS

Home | Current Version | Previous Version | Text Only | Print | Product List | Glossary On
Versions: 1 2
000
FXSA20 KWBC 291358
PMDSA

SOUTH AMERICA SYNOPTIC DISCUSSION - INTERNATIONAL DESKS
NWS WEATHER PREDICTION CENTER COLLEGE PARK MD
857 AM EST THU JAN 29 2015

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

SYNOPSIS (VALID FROM JANUARY 29 AT 00UTC): AT 200 HPA...THE
SUBTROPICAL RIDGE CONTINUES TO BUILD OVER NORTHWEST SOUTH AMERICA
WHILE ANCHORING ON A CLOSED HIGH OVER THE ALTIPLANO OF BOLIVIA.
THIS HIGH EXTENDS A RIDGE TO THE SOUTHEAST ACROSS MATO GROSSO-SAO
PAULO IN BRASIL TO THE SOUTH PACIFIC. A SHORT WAVE TROUGH TO THE
SOUTH...MEANWHILE...EXTENDS NORTH FROM CORRIENTES IN ARGENTINA TO
SOUTHEAST BOLIVIA. THIS...AND THE RIDGE ALOFT...PROVIDE
VENTILATION TO DEEP CONVECTION ACROSS PARAGUAY-BOLIVIA-SOUTHEAST
BRASIL. A RETROGRESSING TUTT LOW TO THE NORTH CENTERS NEAR 09S
35W...EXTENDING A TROUGH TO THE NORTHWEST ACROSS NORTHERN BRASIL
TO THE GUIANAS/COLOMBIA. THIS FAVORS AN UPPER CONVERGENT/SUBSIDENT
PATTERN ALOFT THAT IS INHIBITING DEEP CONVECTION ACROSS BRASIL TO
THE EAST OF 50W.

THE 250 HPA JET ANALYSIS SHOWS THE SOUTHERN POLAR WITH A FINGER
BETWEEN 58S 91W AND 65S 60W. THE NORTHERN POLAR LIES ALONG A 140KT
MAXIMUM AT 51S 121W...45S 101W...55S 86W...61S 64W...LAS MALVINAS/
FALKLAND ISLANDS...EXITING AT 45S 59W. IT REFORMS AT 41S
56W...ALONG A 162KT MAXIMUM AT 46S 44W...47S 35W...A 167KT MAXIMUM
AT 43S 26W...AND 36S 13W. THE SUBTROPICAL JET HAS ITS ENTRANCE AT
41S 105W...ALONG 42S 96W...EXITING AT 46S 87W. IT HAS A FINGER TO
THE EAST THAT EXTENDS BETWEEN 48S 66W AND 38S 63W. THE JET REFORMS
AT 34S 61W...ALONG 40S 50W...43S 40W...39S 28W...EXITING AT 34S
21W.

AT 500 HPA...A BROAD TROUGH ENTERED THE EASTERN SOUTH
PACIFIC...ENVELOPING AREA BETWEEN 130W-80W AND TO THE SOUTH OF
30S...WHILE ANCHORING ON A CLOSED LOW AT 65S 100W. A
NORTH-TO-SOUTH RIDGE TO THE EAST EXTENDS FROM CENTRAL/SOUTHERN
CHILE TO THE ANTARCTIC PENINSULA. DOWNSTREAM FROM THIS AXIS...A
LOW NEAR 53S 49W EXTENDS A TROUGH TO THE NORTHWEST ACROSS RIO DE
LA PLATA/ENTRE RIOS IN ARGENTINA. THIS IS FOCUSING SHORT WAVE
ENERGY ACROSS URUGUAY/ENTRE RIOS IN ARGENTINA. A RIDGE TO THE
NORTH EXTENDS WEST ACROSS SOUTHEAST TO CENTRAL BRASIL.

AT LOW LEVELS...AN OCCLUDED 954 HPA LOW AT 68S 106W EXTENDS A
FRONT ALONG A 968 HPA LOW AT 71S 81W...64S 75W...A 974 HPA LOW AT
57S 87W...50S 97W...A 998 HPA LOW AT 40S 98W...AND 38S 109W. ON
THE NORTHERN STREAM...FARTHER TO THE EAST...AN OCCLUDED 986 HPA
LOW AT 51S 47W EXTENDS A FRONT ALONG A 994 HPA LOW AT 50S
39W...45S 37W...A 1006 HPA LOW AT 42S 40W...39S 41W...A 1006 HPA
LOW AT 36S 45W...A 1006 HPA LOW AT 33S 51W...SOUTHERN BRASIL TO
MENDOZA IN ARGENTINA. THIS SUSTAINS SCATTERED DEEP CONVECTION
ACROSS RN BRASIL TO NORTHERN PROVINCES IN ARGENTINA. A POLAR RIDGE
TO THE SOUTH CENTERS ON A 1017 HPA HIGH AT 42S 61W.


ARREAGA...INAMHI (ECUADOR)
DURAN...SENAHMI (PERU)
DAVISON...WPC (USA)
GALVEZ...WPC (USA)

$$




USA.gov is the U.S. government's official web portal to all federal, state and local government web resources and services.