000
AXPZ20 KNHC 201607
TWDEP 

TROPICAL WEATHER DISCUSSION
NWS TPC/NATIONAL HURRICANE CENTER MIAMI FL
1605 UTC TUE NOV 20 2007

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

BASED ON 1200 UTC SURFACE ANALYSIS AND SATELLITE IMAGERY THROUGH 
1515 UTC.

...TROPICAL WAVES...

TROPICAL WAVE ALONG 93W/94W N OF 10N MOVING W 10 KT. NO 
SIGNIFICANT CONVECTION.

TROPICAL WAVE ALONG 80W/81W N OF 8N MOVING W 10-15 KT. SCATTERED 
MODERATE TO STRONG CONVECTION IS CONFINED THE SW CARIBBEAN AND 
EXTENDING TO THE COASTS OF PANAMA...COSTA RICA AND NICARAGUA.

...ITCZ...

ITCZ AXIS IS CENTERED ALONG 9N84W 6N100W 8N120W 10N140W. 
SCATTERED MODERATE WITHIN 90 NM OF AXIS BETWEEN 118W AND 
122W....AND WITHIN 60-90 NM OF THE AXIS BETWEEN 127W AND 133W. 

...DISCUSSION...

OMEGA TYPE BLOCKING PATTERN IN PLACE OVER THE DISCUSSION AREA 
WITH TWO WELL DEFINED CYCLONIC CIRCULATIONS AFFECTING THE AREA
WITH A RIDGE IN BETWEEN. THE FIRST CYCLONIC CIRCULATION IS 
LOCATED WELL W OF THE AREA NEAR 24N148W WAS LIFTING NWD AT 10-15 
KT AS DRY AIR WRAPPED AROUND THE BASE OF THE CIRCULATION. A MID 
TO UPPER LEVEL RIDGE AXIS WAS ALONG 128W. STRONGLY DIFFLUENT 
FLOW WAS NOTED BETWEEN THE RIDGE AXIS AND THE CYCLONIC 
CIRCULATION MAINLY W OF 130W. THIS FLOW WAS NOT ONLY ENHANCING  
ITCZ CONVECTION BUT WAS ALSO PRODUCING A VAST AREA OF BROKEN TO 
OVERCAST MID AND HIGH CLOUDS IN THE AREA. 

FURTHER E...A VERTICALLY STACKED CUT OFF CYCLONIC CIRCULATION 
WAS CENTERED OVER THE SRN TIP OF BAJA CALIFORNIA NEAR 24N109W 
PRODUCING DRY AIR AND LIMITED CLOUDINESS IN THE MIDDLE AND UPPER 
LEVELS. A PLUME OF UPPER LEVEL MOISTURE EMANATING FROM ITCZ 
CONVECTION IS S OF THE CUT OFF LOW WITH A JET MAXIMUM EXTENDING 
FROM 17N120W THROUGH 15N115W TO THE COAST OF MEXICO NEAR 20N107W.
SATELLITE DERIVED WINDS INDICATED CORE SPEEDS OF 80-90 KT. 
SOME TRANSVERSE BANDING WAS ALSO INDICATED SUGGESTED MODERATE OR 
GREATER MID TO HIGH ALTITUDE TURBULENCE. 
   
AT THE SURFACE...WEAK RIDGE IS NORTH OF THE ITCZ WEST OF 110W. A 
WEAKENING FRONTAL BOUNDARY WAS NOTED ALONG 31N AND IS EXPECTED
TO DISSIPATE IN THE FACE OF THE RIDGE. 

THE LATEST QUIKSCAT PASS MISSED THE GULF OF TEHUANTEPEC. 
HOWEVER...SURFACE OBSERVATIONS FROM SALINA CRUZ INDICATED 
NLY WINDS OF 15-25 KT SUGGESTED THE MOST RECENT WIND SURGE WAS
CONTINUING. NWP MODELS ARE FORECASTING WINDS TO DECREASE BELOW 
20 KT WITHIN 24 HOURS. A HIGH RESOLUTION QUIKSCAT PASS SHOWED 
THAT 20 KT WINDS WERE OCCURRING IN THE GULF OF PAPAGAYO WITH 
LITTLE CHANGE IN INTENSITY EXPECTED THROUGH THE NEXT 48 HOURS. 

$$
COBB