000
AXPZ20 KNHC 180306
TWDEP 

TROPICAL WEATHER DISCUSSION  
NWS TPC/NATIONAL HURRICANE CENTER MIAMI FL
0405 UTC WED OCT 18 2006

TROPICAL WEATHER DISCUSSION FOR THE EASTERN PACIFIC OCEAN FROM 
THE EQUATOR TO 32N...EAST OF 140W. THE FOLLOWING INFORMATION IS 
BASED ON SATELLITE IMAGERY...WEATHER OBSERVATIONS...RADAR...AND 
METEOROLOGICAL ANALYSIS.

BASED ON 0000 UTC SURFACE ANALYSIS AND SATELLITE IMAGERY THROUGH 
0245 UTC.

...TROPICAL WAVES...

TROPICAL WAVE ALONG 96W/97W N OF 5N MOVING W 10-15 KT. THE WAVE 
REMAINS EMBEDDED WITH AN ENVIRONMENT OF MODERATE LOW-LEVEL 
SW/WLY FLOW WHICH IS MAKING IT DIFFICULT TO LOCATE. IN 
ADDITION...DEEP CONVECTION IS PRIMARILY ORIENTED LINEARLY ALONG 
THE ITCZ WITH NO APPARENT ORGANIZATION AROUND THE WAVE.

...ITCZ...

ITCZ AXIS IS CENTERED ALONG 8N77W 12N89W 14N105W 9N120W 7N130W 
7N140W. SCATTERED MODERATE/ISOLATED STRONG CONVECTION WITHIN 240 
NM OF THE AXIS BETWEEN 84W-107W. SCATTERED MODERATE WITHIN 150 
NM OF THE AXIS BETWEEN 115W-126W.

...DISCUSSION...

MID/UPPER LEVEL TROUGH PATTERN CONTINUES TO SIT OVER THE WESTERN 
U.S. WITH A FEW SHORTWAVES ROTATING AROUND THE BASE ACROSS THE N 
PART OF THE DISCUSSION AREA. ONE SHORTWAVE TROUGH EXTENDS FROM 
THE NRN GULF OF CALIFORNIA SW TO 20N120W AND IS PRECEDED BY A 
LARGE AREA OF STRONG SUBSIDENCE EXTENDING UP TO 750 NM SW OF THE 
BAJA PENINSULA. A SECOND BROADER SHORTWAVE EXTENDS FROM 30N130W 
TO 20N140W AND IS ADVECTING ADDITIONAL DRY AIR INTO THE AREA. 
EACH OF THESE SHORTWAVES IS HELPING TO PUSH A DYING COLD FRONT 
SWD FROM 30N111W SW TO 26N124W 27N134W...FOLLOWED BY A WEAK WIND 
SURGE AND A BAND OF STRATOCUMULUS.

AN UPPER RIDGE AXIS ANCHORED OVER THE GULF OF MEXICO EXTENDS SW 
ACROSS MEXICO TO NEAR 11N125W AND MARKS A DIVIDING LINE BETWEEN 
DRY AIR TO THE NW AND MOIST AIR TO THE SE. LOW-LEVEL CONVERGENCE 
ALONG THE ITCZ IS PRODUCING CLUSTERS OF DEEP CONVECTION ACROSS 
MOST OF ITS LENGTH AND OUTFLOW FROM THE RIDGE IS AIDING IN 
COVERAGE. THE FAR E PACIFIC WATERS LIE S OF THE GULF OF MEXICO 
UPPER HIGH...AND HENCE IS UNDER MAINLY ELY MID/UPPER LEVEL FLOW. 
CONVECTION IS ALSO QUITE ACTIVE ALONG THE ITCZ IN THIS 
REGION...BUT THE VERTICAL SHEAR IS CAUSING MAINLY FAST-MOVING 
MESOSCALE COMPLEXES THAT ARE NOT ABLE TO ORGANIZE. OFFSHORE 
CONVECTION HAS BEGUN TO WANE A LITTLE BIT AND NOW NEW TSTMS ARE 
DEVELOPING ALONG THE LAND BREEZE JUST OFF THE CENTRAL AMERICAN 
COAST. ONE STRONG CLUSTER IS LOCATED OVER THE GULF OF 
TEHUANTEPEC WITH ANOTHER OFF THE COAST OF COSTA RICA.

$$
BERG