000
AXPZ20 KNHC 180942
TWDEP 

TROPICAL WEATHER DISCUSSION
NWS TPC/NATIONAL HURRICANE CENTER MIAMI FL
1005 UTC SUN NOV 18 2007

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

BASED ON 0600 UTC SURFACE ANALYSIS AND SATELLITE IMAGERY THROUGH 
0900 UTC.

...ITCZ...
ITCZ AXIS IS CENTERED ALONG 9N84W 7N94W 9N110W 10N140W. SCATTERED 
MODERATE ISOLATED STRONG CONVECTION WITHIN 75 NM OF AXIS BETWEEN 
111W AND 136W.

...DISCUSSION...
PRIMARY FEATURE IN THE EASTERN PART OF THE DISCUSSION AREA IS A MID 
LATITUDE TROUGH ALONG 110W THAT EXTENDS DEEP INTO THE TROPICS TO 10N.
INTERACTION BETWEEN THIS TROUGH AND THE BROAD UPPER RIDGE OVER THE 
WESTERN CARIBBEAN AND THE GULF OF MEXICO IS CREATING A SUBTROPICAL 
JET STREAMING MOISTURE ACROSS CENTRAL MEXICO TO THE U.S. GULF COAST.
STRONG SUBSIDENCE ALONG THE TROUGH AXIS IS EVIDENCED BY A PRONOUNCED 
DRYING OBSERVED OVER THE GULF OF CALIFORNIA IN ANIMATED WATER VAPOR 
IMAGERY. THE OTHER PRIMARY FEATURE IS A SUBTROPICAL LOW WEST OF THE 
AREA NEAR 15N150W THAT EXTENDS TO THE SURFACE. BROAD RIDGING BETWEEN 
THE LOW AND THE TROUGH ALONG 110W IS CREATING A FAVORABLE ENVIRONMENT
FOR PERSISTENT UPPER LEVEL CLOUDINESS. UPPER LEVEL WINDS WEST OF THE 
SUBTROPICAL LOW ARE LIGHT AND BROADLY DIVERGENT. THIS IS ALLOWING THE
CONVECTION FIRING ALONG THE ITCZ W OF THE TROUGH ALONG 110W TO BECOME
MORE ACTIVE. THIS PATTERN WILL HOLD FOR A WHILE AS THE SUBTROPICAL 
LOW DEEPENS BUT REMAINS NEARLY STATIONARY AND THE TROUGH ALONG 110W 
BECOMES A CUT OFF LOW...AMPLIFYING THE RIDGE IN BETWEEN AS WELL. 

AT THE SURFACE...GAP WINDS HAVE ABATED CONSIDERABLY IN THE GULF OF 
TEHUANTEPEC AND ARE EXPECTED TO PERSIST AT AROUND 20 KT FOR THE GULF 
OF PAPAGAYO. THE NEXT SURGE OF HIGH PRESSURE IN THE WESTERN GULF 
COMMENCES IN 24 HOURS AND CONTINUES INTO MON WITH WINDS INCREASING TO
25 TO 30 KT IN THE GULF OF TEHUANTEPEC BY LATE MON.

$$
MUNDELL