East Pacific Tropical Weather Discussion

000
AXPZ20 KNHC 092156
TWDEP 

TROPICAL WEATHER DISCUSSION  
NWS TPC/NATIONAL HURRICANE CENTER MIAMI FL
2205 UTC MON NOV 09 2009

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

BASED ON 1800 UTC SURFACE ANALYSIS AND SATELLITE IMAGERY THROUGH 
2145 UTC.

...ITCZ...

THE ITCZ AXIS EXTENDS FROM 08N81W TO 08N110W TO 11N119W TO 
08N140W. SCATTERED MODERATE ISOLATED STRONG CONVECTION IS 
OBSERVED FROM 08N TO 16N BETWEEN 108W AND 123W SURROUNDING TWO 
PERSISTENT LOW PRESSURE CENTERS. ONE LOW IS NEAR 10N122W 1008 MB 
AND APPEARS TO BE LOSING IDENTITY AS EXPECTED. A SECOND LOW 
PRESSURE CENTER IS NEAR 11N113W 1008 MB...AND IS THE MEAN CENTER 
OF A MUCH BROADER AREA OF PERSISTENT LOW PRESSURE THAT CONTINUES 
TO PRODUCE TROPICAL CONVECTION. SCATTERED MODERATE ISOLATED 
STRONG CONVECTION IS ALSO NOTED WITHIN 15 NM EITHER SIDE OF A 
LINE FROM 08N134W TO 09N139W.

...DISCUSSION...

AN UPPER ANTICYCLONE IS CENTERED NEAR 12N108W WITH A RIDGE 
EXTENDING SW TO NEAR 08N125W AND A RIDGE ALSO EXTENDS SE TO A 
CREST AT 12N101W. CONVECTION IS ENHANCED UNDER THE RIDGE AS 
PREVIOUSLY DESCRIBED...WITH THE DEBRIS MOISTURE ADVECTED NE TO 
ACROSS OLD MEXICO BETWEEN 16N AND 24N. 

AN UPPER TROUGH IS NOTED OVER THE W PORTION FROM 22N127W TO 
14N137W. THE UPPER FLOW HAS BECOME ZONAL N OF 20N WITH A PLUME 
OF MOISTURE THAT ORIGINATES IN THE CENTRAL PACIFIC CONTINUING TO 
STREAM EASTWARD OVER THE DISCUSSION AREA N OF A LINE FROM 
22N140W TO 27N111W. 

AN UPPER TROUGH EXTENDS S ALONG 32N103W TO NEAR 17N93W THEN 
CONTINUES S CROSSING THE EQUATOR AT 92W. A BAND OF DRY UPPER AIR 
IS SWEEPING E ACROSS THE DISCUSSION WITHIN 330 NM EITHER SIDE OF 
LINE FROM 14N140W TO 21N127W THEN THE BAND NARROWS OVER THE AREA 
FROM 21N TO 26N BETWEEN 127W AND 106W THEN MERGES WITH 
ADDITIONAL DRY AIR THAT COVERS THE UPPER LEVELS S OF 26N BETWEEN 
102W AND 88W. 

AN UPPER ANTICYCLONE IS NEARLY STATIONARY OVER THE W CARIBBEAN 
NEAR 17N82W WITH A RIDGE EXTENDING SW TO NEAR 08N87W. CONVECTION 
IS ENHANCED UNDER THE RIDGE OVER NW COLOMBIA...PANAMA...COSTA 
RICA AND NICARAGUA WITH SOME OF THE DEBRIS MOISTURE SPREADING W 
OVER THE DISCUSSION AREA N OF 04N E OF 90W.

AT THE LOW LEVELS HIGH PRES IS CENTERED AT 31N133W 1021 MB WITH 
A RIDGE EXTENDING SE TO NEAR 15N107W. N TO NE TO E WINDS ARE 
GENERALLY 15 KT THROUGH THE RIDGE EXCEPT FOR A SMALL AREA OF NE 
TRADES AT 20 KT SW OF THE RIDGE. NW SWELLS CONTINUE TO SPREAD SE 
ACROSS THE AREA W OF 100W AND WILL BE REINFORCED IN THE WAKE OF 
ANOTHER COLD FRONT WED NIGHT.

GAP WINDS...
N WINDS AT 15 TO 20 KT IN GULF OF TEHUANTEPEC WILL INCREASE TO 
GALE FORCE LATE TONIGHT AND CONTINUE THROUGH WED.

$$
NELSON