Prognostic Meteorological Discussion
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FXSA20 KWBC 301324
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SOUTH AMERICA SYNOPTIC DISCUSSION - INTERNATIONAL DESKS
NWS WEATHER PREDICTION CENTER COLLEGE PARK MD
924 AM EDT WED JUL 30 2014

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

SYNOPSIS (VALID FROM 29 JULY 00UTC): AT 200 HPA...A CLOSED HIGH
OVER WESTERN ECUADOR ANCHORS A RIDGE OVER THE EASTERN TROPICAL
PACIFIC...WITH AXIS SOUTH ALONG 80W TO 20S. EAST OF THIS RIDGE...A
SHORT WAVE TROUGH EXTENDS NORTH ACROSS RONDONIA-AMAZONAS IN
BRASIL. THIS TROUGH...ALTHOUGH WEAKENING...CONTINUES TO ENHANCE
DIURNAL CONVECTION ACROSS AMAZONAS-PARA IN BRASIL. TRADE WIND
CONVERGENCE ACROSS NORTHEAST BRASIL FAVORS LIGHT SHALLOW
CONVECTION TO THE EAST OF 38W.

AT 250 HPA...THE SOUTHERN POLAR HAS ITS ENTRANCE AT 47S
85W...ALONG 53S 79W...51S 70W...EXITING AT 45S 67W. IT REFORMS AT
45S 55W...ALONG 49S 41W...48S 28W...EXITING AT 44S 24W. THE
NORTHERN POLAR LIES ALONG 35S 120W...A 177KT MAXIMUM AT 35S
110W...34S 98W...A 144KT MAXIMUM AT 35S 90W...41S 82W...44S
75W...39S 66W...38S 58W...42S 49W...EXITING AT 44S 38W. THE
SUBTROPICAL JET HAS A FINGER BETWEEN 19S 76W AND 17S 72W. IT
REFORMS AT 13S 46W...ALONG 17S 39W...19S 30W...20S 21W...EXITING
AT 19S 15W.

AT 500 HPA...BROAD TROUGH ON THE SOUTHERN STREAM REMAINS ACROSS
THE FAR EASTERN PACIFIC...ENVELOPING AREA BETWEEN 105W-70W AND TO
THE SOUTH OF 30S. THE TROUGH CENTERS ON A CLOSED LOW NEAR 56S
100W. AS IT PRESSES AGAINST A SHORT WAVE RIDGE TO THE EAST THIS IS
FOCUSING SHORT WAVE ENERGY ACROSS SOUTHERN-CENTRAL PORTIONS OF
CHILE. SHORT WAVE PERTURBATIONS ON THE NORTHERN STREAM REVOLVE
AROUND THIS TROUGH...WITH ONE ALONG 92W/93W TO 28S...WHILE ANOTHER
IS PULLING ACROSS LA PAMPA TO THE BUENOS PROVINCE IN ARGENTINA.
THE LATTER SUSTAINS SCATTERED DEEP CONVECTION ACROSS SOUTHERN
BRASIL-URUGUAY-MESOPOTAMIA VALLEY IN ARGENTINA. A RIDGE OVER THE
WESTERN ATLANTIC EXTENDS BETWEEN 55W-30W AND TO THE NORTH OF 50S.
A TROUGH TO THE EAST EXTENDS BETWEEN 30W-10W AND TO THE SOUTH OF
20S.

AT LOW LEVELS...SURFACE ANALYSIS SHOWS A BROAD TROUGH OVER THE
SOUTHEAST PACIFIC THAT CENTERS ON AN OCCLUDED 974 HPA LOW AT 56S
100W. A POLAR FRONT TO THE NORTH REVOLVES AROUND THIS AXIS AS IT
EXTENDS FROM AN OCCLUDED 966 HPA LOW AT 45S 93W...A 970 HPA LOW AT
48S 86W...42S 82W...38S 84W...A 1006 HPA LOW AT 36S 87W...31S
98W...AND 31S 111W. FARTHER EAST...AN OCCLUDED 990 HPA LOW AT 57S
50W EXTENDS A FRONT ALONG A 994 HPA LOW AT 59S 44W...53S 38W...49S
40W...45S 50W...A 1010 HPA LOW AT 43S 59W...BUENOS AIRES ARGENTINA
TO MENDOZA. SCATTERED CONVECTION WAS BUILDING AHEAD OF THIS FRONT
OVER URUGUAY-ENTRE RIOS ARGENTINA. A RIDGE OVER THE ATLANTIC
CENTERS ON A 1037 HPA HIGH AT 39S 36W. AN OLD FRONT TO THE EAST
EXTENDS ALONG A 1014 HPA LOW AT 29S 17W...23S 22W...21S 27W...TO
ESPIRITO SANTO...WHERE IT SUSTAINS SCATTERED CONVECTION.

FERNANDES...INMET (BRASIL)
JALFIN...SMN (ARGENTINA)
DAVISON...WPC (USA)

$$





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