000
AXPZ20 KNHC 090352
TWDEP 

TROPICAL WEATHER DISCUSSION
NWS TPC/NATIONAL HURRICANE CENTER MIAMI FL
0405 UTC SAT OCT 09 2010

TROPICAL WEATHER DISCUSSION FOR THE EASTERN PACIFIC OCEAN
FROM THE EQUATOR TO 32N...EAST OF 140W.

BASED ON 0000 UTC SURFACE ANALYSIS AND SATELLITE IMAGERY THROUGH 
0315 UTC.

...ITCZ...

ITCZ AXIS ALONG 09N83W TO 07N95W TO 1011 MB LOW PRES AT 09N113W 
TO 08N117W TO 1011 MB LOW PRESSURE AT 11N123W TO 09N140W. 
SCATTERED MODERATE CONVECTION IS WITHIN 120 NM NE QUADRANT OF 
LOW PRESSURE AT 11N123W. SCATTERED MODERATE AND ISOLATED STRONG 
CONVECTION IS FROM 09N TO 11N BETWEEN 123W AND 131W AND WITHIN 
90 NM N OF THE AXIS W OF 137W.

...DISCUSSION...

A PROGRESSIVE AND GENERALLY ZONAL FLOW PATTERN PREVAILS N OF 30W 
FROM BEYOND 160W TO THE W COAST OF N AMERICA...ALLOWING A SERIES 
OF UPPER LEVEL TROUGHS TO MOVE E ACROSS THE SUBTROPICAL PORTION 
OF THE DISCUSSION AREA. CURRENTLY...AN UPPER LEVEL TROUGH AXIS 
SLICES THROUGH THE NW PORTION OF THE DISCUSSION AREA FROM 
34N120W SW TO 23N133W AND BEYOND 21N140W...AND IS ACCOMPANIED BY 
UPPER LEVEL MOISTURE W OF THE TROUGH AXIS N OF 27N. THIS 
MOISTURE CURLS AROUND THE NORTHEASTERN PERIPHERY OF AN UPPER 
LEVEL ANTICYCLONE CENTERED NEAR 30N139W. FARTHER TO THE SE... 
ANOTHER UPPER LEVEL ANTICYCLONE IS CENTERED NEAR 16N102W...WITH 
AN UPPER LEVEL RIDGE AXIS EXTENDING W TO NEAR 16N120W AND NE 
ACROSS MEXICO TO SOUTHERN TEXAS. W TO SW UPPER LEVEL FLOW 
DOMINATES THE AREA TO THE W AND NW OF THE UPPER RIDGE...AND SE 
OF THE AFOREMENTIONED UPPER LEVEL TROUGH. A SHARP AND NEGATIVELY 
TILTED UPPER LEVEL TROUGH UNDERCUTS THE RIDGE...EXTENDING FROM 
13N126W SE TO 07N117W THEN TO NW OF THE GALAPAGOS ISLANDS NEAR 
04N98W. THIS TROUGH CROSSES THE ITCZ BETWEEN 118W AND 126W AND 
CONTINUES VENTILATING MODEST ITCZ CONVECTION FROM 09N TO 13N 
BETWEEN 120W AND 126W. UPPER LEVEL RIDGING EXTENDS ACROSS THE 
FAR WESTERN CARIBBEAN SW INTO THE TROPICAL E PACIFIC E OF 92W... 
AND YIELDS MODERATELY STABLE CONDITIONS ALOFT DUE TO 
CONFLUENCE.  

AT THE LOW LEVELS...A 1023 MB HIGH IS CENTERED NEAR 30N130W WITH 
A RIDGE AXIS EXTENDING SW TO JUST N OF THE HAWAIIAN ISLANDS AND 
SE TO 18N111W. AN EARLIER ASCAT PASS AROUND 08/1844 UTC DEPICTED 
MODERATE TO FRESH NE TO E TRADES S OF THE RIDGE FROM 10N TO 20N 
W OF 118W...WITH TWO WEAK CYCLONIC SWIRLS NOTED ABOVE EMBEDDED 
WITHIN THE ITCZ. SEAS ACROSS THIS AREA WERE GENERALLY RUNNING 8 
TO 11 FT. LITTLE CHANGE IS ANTICIPATED IN THIS SYNOPTIC SCENARIO 
OVER THE NEXT 48 HOURS AS THESE WEAK LOWS MOVE W AT 10 TO 15 KT. 
EXPECT HIGHEST WINDS 20 KT AND SEAS 10 TO 11 FT TO REMAIN N OF 
THE LOWS BETWEEN 118W AND 132W. 

E OF THIS AREA...NORTHERLY GAP WIND FLOW THROUGH THE GULF OF 
TEHUANTEPEC CONTINUES AT 20 TO 30 KT...WHICH IS THEN FLOWING SW 
TO W AND DOWNSTREAM TO S OF 14N AND W TO 101W. SATELLITE IMAGERY 
ALSO SUGGESTS NLY FLOW ACROSS THE FAR W AND SW CARIBBEAN IS 
FLOWING ACROSS CENTRAL AMERICA THEN TURNING NE AND EXITING THE 
PACIFIC COASTS E OF 92W...ALL CONTRIBUTING TO RELATIVELY DRY AND 
STABLE LOW-LEVEL FLOW. A WEAK CYCLONIC CIRCULATION IS SUGGESTED 
IN SATELLITE IMAGERY ALONG THE ITCZ DUE TO THIS NELY FLOW...NEAR 
09N85W. EXPECT THE TEHUANTEPEC WINDS TO GRADUALLY DIMINISH TO 20 
KT LATE SAT AND TO LESS THAN 20 KT EARLY SUN AS FLOW IN THE SW 
GULF OF MEXICO VEERS MORE E.

$$
HUFFMAN