Prognostic Meteorological Discussion
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FXSA20 KWBC 041259
PMDSA

SOUTH AMERICA SYNOPTIC DISCUSSION - INTERNATIONAL DESKS
NWS WEATHER PREDICTION CENTER COLLEGE PARK MD
859 AM EDT WED MAY 04 2016

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

SYNOPSIS (VALID FROM MAY 04 AT 0000 UTC): NORTH OVER THE
CONTINENT...AT 200 HPA...A NORTHERN HEMISPHERE TUTT EXTENDS ACROSS
VENEZUELA TO NORTHERN AMAZONAS IN BRASIL. THIS FAVORS A DIFFLUENT
PATTERN ALOFT ACROSS NORTHERN PARA-NORTH COAST OF BRASIL...WHERE
IT WAS VENTING LATE AFTERNOON DEEP CONVECTION ACROSS EQUATORIAL
SOUTH AMERICA.

THE 250 HPA JET ANALYSIS SHOWS THE SOUTHERN POLAR WITH AXIS ALONG
72S 82W...THEN ALONG A 125KT MAXIMUM AT 65S 70W...EXITING AT 55S
62W. IT REFORMS AT 50S 51W...THEN ALONG 47S 38W...43S 26W...48S
16W...AND A 170KT MAXIMUM AT 54S 08W. THE NORTHERN POLAR HAS ITS
ENTRANCE AT 48S 76W...THEN ALONG 45S 63W...EXITING AT 40S 52W. THE
SUBTROPICAL JET LIES ALONG A 176KT MAXIMUM AT 32S 118W...A 165KT
MAXIMUM AT 33S 108W...A 162KT MAXIMUM AT 30S 97W...26S
89W...EXITING AT 26S 85W. IT HAS A FINGER BETWEEN 29S 82W AND 34S
72W. THE SUBTROPICAL JET REFORMS AT 33S 59W...THEN ALONG 28S
50W...28S 39W...34S 23W...40S 10W...AND 45S 02W.

AT 500 HPA...A LOW NEAR 45S 100W EXTENDS A TROUGH ALONG 35S
95W...TO 20S 95W. THIS IS PRESSING AGAINST A RIDGE TO THE EAST
THAT EXTENDS ALONG THE COAST OF CHILE TO THE BELLINGSHAUSEN SEA.
UNDER INFLUENCE OF THE RIDGE TO THE WEST...A SOUTHERN STREAM
PERTURBATION IS SURGING ACROSS THE ANTARCTIC PENINSULA/SOUTHWEST
ATLANTIC TO 40S. AS IT DEEPENS...THE TROUGH IS PHASING WITH A
NORTHERN STREAM SHORT WAVE TROUGH OFF OVER SOUTHERN BRASIL/URUGUAY.

AT LOW LEVELS...THE SURFACE ANALYSIS SHOWS A RIDGE THAT EXTENDS
ALONG THE COAST OF CHILE...WITH AXIS ANCHORING ON TWO CLOSED 1023
HPA HIGHS...WITH ONE AT 58S 89W AND THE OTHER AT 52S 78W. A TROUGH
TO THE WEST PRESSES AGAINST THIS RIDGE...WITH POLAR FRONT
EXTENDING FROM AN OCCLUDED 986 HPA LOW AT 45S 97W...A 1004 HPA LOW
AT 45S 89W...43S 82W...A 1008 HPA LOW AT 38S 86W...33S 84W...A
1010 HPA LOW AT 29S 88W...AND 25S 93W. EAST OF THE RIDGE...OVER
THE SOUTH ATLANTIC...AN AMPLIFYING TROUGH DOMINATES THE COAST OF
SOUTHERN ARGENTINA...WITH A POLAR FRONT EXTENDING FROM AN OCCLUDED
982 HPA LOW AT 57S 46W...A 986 HPA LOW AT 55S 40W...51S 40W...A
990 HPA LOW AT 54S 47W...52S 51W...A 1002 HPA LOW AT 51S 55W...44S
60W..TO NORTHERN PATAGONIA IN ARGENTINA. THIS FAVORS LIGHT RAIN
ACROSS THE SOUTHERN ANDES OF CHILE. AN ELONGATED FRONT TO THE
NORTH LIES ALONG 34S 24W...31S 36W...A 1018 HPA LOW AT 32S
45W...SANTA CATARINA TO CORRIENTES IN ARGENTINA-CORDOBA. A RIDGE
TO THE SOUTH CENTERS ON A 1025 HPA HIGH OVER URUGUAY...AND A 1023
HPA HIGH AT 38S 48W. AN OLD BOUNDARY TO THE NORTH EXTENDS ALONG
28S 18W...22S 27W...TO VITORIA IN BRASIL. THIS SUSTAINS A
PREFRONTAL SHEAR LINE ACROSS BAHIA...WHERE IT SUSTAINS COASTAL
CONVECTION.

AYALA...DINAC (PARAGUAY)
ENRIQUEZ...DGAC (ECUADOR)
DAVISON/GALVEZ...WPC (USA)
$$




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