000
AXPZ20 KNHC 212132
TWDEP 

TROPICAL WEATHER DISCUSSION
NWS TPC/NATIONAL HURRICANE CENTER MIAMI FL
2205 UTC WED NOV 21 2007

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 
2115 UTC.

...TROPICAL WAVES...

TROPICAL WAVE ACROSS COSTA RICA AND NICARAGUA ALONG 83W/84W N OF 
6N MOVING W 10 KT. SCATTERED MODERATE CONVECTION IS MOVING 
INLAND ACROSS ERN NICARAGUA AND HONDURAS FROM THE W CARIBBEAN 
WATERS AND SOME ACTIVITY IS ALSO AFFECTING PORTIONS OF COSTA 
RICA DUE TO THE PROXIMITY OF THE ITCZ. SCATTERED MODERATE N OF 
9N BETWEEN 83W-86W.

TROPICAL WAVE ALONG 97W HAS BEEN REMOVED FROM THE SURFACE 
ANALYSIS SINCE IT HAS LOST ALL OF ITS ENERGY. THE AREA IS 
VIRTUALLY CLOUDLESS DUE TO EXCESSIVE DRY AIR...AND THE ITCZ IS 
QUITE LINEAR IN THE VICINITY.

...ITCZ...

ITCZ AXIS IS CENTERED ALONG 7N77W 9N85W 7N100W 7N120W 9N140W. 
SCATTERED MODERATE N OF 6N E OF 81W OVER THE GULF OF PANAMA.

...DISCUSSION...

E OF 120W...
A NEARLY STATIONARY UPPER TROUGH IS ANCHORED JUST OFF THE W 
COAST OF MEXICO WITH A MEAN AXIS ALONG 115W. HOWEVER...SEVERAL 
SHORTWAVES ARE NOTED WITHIN THE TROUGH. ONE SHORTWAVE EXTENDS 
FROM S TEXAS ACROSS NRN MEXICO TO NEAR 20N120W AND IS ASSOCIATED 
WITH A 70-90 KT JET WHICH EXTENDS ACROSS MEXICO FROM CABO 
CORRIENTES TO BROWNSVILLE TEXAS. THE UPPER FLOW AHEAD OF THE 
TROUGH IS PRIMARILY SOUTH TO SOUTHWESTERLY BUT THERE IS 
RELATIVELY LITTLE AVAILABLE MOISTURE IN THE DEEP TROPICS SO THE 
CIRRUS PLUME IS QUITE MEAGER. IN ADDITION...THE LOW-LEVELS ARE 
ALSO VERY DRY AND SKIES ARE VIRTUALLY CLOUDLESS N OF THE ITCZ W 
OF 87W. THE SECOND SHORTWAVE/CLOSED LOW HAS BEEN PLUNGING S 
ALONG THE CALIFORNIA COAST AND IS NOW CENTERED JUST SW OF SAN 
DIEGO NEAR 32N119W. THE LOW IS BOUNDED BY A WEAK 50-60 KT JET ON 
ITS SW PERIPHERY AND IS ASSOCIATED WITH A RELATIVELY SMALL CLOUD 
FIELD MOVING ACROSS FAR NW MEXICO FROM 29N-34N BETWEEN 
110W-118W. RADAR IMAGERY FROM YUMA ARIZONA SHOWS THAT SCATTERED 
SHOWERS ARE EMBEDDED WITHIN THIS CLOUD MASS AND ARE MOVING EWD 
ACROSS THE FAR NRN PARTS OF THE STATES OF BAJA CALIFORNIA NORTE 
AND SONORA...AS WELL AS NRN PARTS OF THE GULF OF CALIFORNIA.

W OF 120W...
AN UPPER RIDGE AXIS IS ALIGNED ALONG 131W MAINLY N OF 10N AND IS 
LOCATED JUST DOWNSTREAM OF A LARGE UPPER TROUGH LOCATED NEAR THE 
HAWAIIAN ISLANDS. A COUPLE OF SURFACE LOWS AND TROUGHS ARE 
LOCATED BENEATH THE DIVERGENT REGIME OF THE TROUGH BUT REMAIN W 
OF 140W. HOWEVER...THE UPPER LEVEL WESTERLY FLOW IS ADVECTING 
MUCH OF THE ASSOCIATED UPPER MOISTURE INTO THE AREA N OF 10N W 
OF 126W AND SCATTERED MODERATE CONVECTION HAS ALSO DEVELOPED 
RIGHT ALONG THE BOUNDARY FROM 16N-20N W OF 139W. FARTHER S...A 
LARGE UPPER LOW IS LOCATED WELL S OF THE EQUATOR NEAR 9S143W BUT 
THE CLOCKWISE FLOW AROUND IT IS EFFECTING THE WIND FLOW OVER THE 
DISCUSSION AREA BY PRODUCING A SPLIT FLOW REGIME OVER THE DEEP 
TROPICS W OF 115W. MOISTURE IS NOT READILY AVAILABLE HOWEVER... 
AND THE ITCZ REMAINS RELATIVELY INACTIVE.

$$
BERG