000
AXPZ20 KNHC 172113
TWDEP 

TROPICAL WEATHER DISCUSSION  
NWS TPC/NATIONAL HURRICANE CENTER MIAMI FL
2205 UTC TUE OCT 17 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 1800 UTC SURFACE ANALYSIS AND SATELLITE IMAGERY THROUGH 
2045 UTC.

...TROPICAL WAVES...

TROPICAL WAVE ALONG 94W/95W N OF 5N MOVING W 10-15 KT. THE WAVE 
IS EMBEDDED WITHIN A LARGE AREA OF LOW-LEVEL SW/WLY FLOW AND 
THEREFORE HAS VERY LITTLE OBVIOUS CIRCULATION. A LARGE AREA OF 
DEEP CONVECTION IS PROPAGATING QUICKLY WWD NEAR THE WAVE AXIS 
FROM 9N-14N BETWEEN 91W-98W.

...ITCZ...

ITCZ AXIS IS CENTERED ALONG 8N77W 12N89W 14N105W 9N118W 9N124W 
7N140W. WIDELY SCATTERED SHOWERS/TSTMS N OF 4N BETWEEN 79W-85W. 
SCATTERED MODERATE CONVECTION FROM 9N-15N BETWEEN 91W-107W. 
SCATTERED MODERATE WITHIN 180 NM OF THE AXIS BETWEEN 115W-132W.

...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 20N122W 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 30N133W 
TO 23N140W AND IS ADVECTING ADDITIONAL DRY AIR INTO THE AREA. 
EACH OF THESE SHORTWAVES IS HELPING TO PUSH A WEAK COLD FRONT 
SWD FROM 32N112W ALONG THE MX/AZ BORDER SW TO 27N120W 
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. MOST OF THE 
CONVECTION LIES OFFSHORE THE CENTRAL AMERICAN COAST...EXCEPT FOR 
SOME SHOWER/TSTM ACTIVITY OVER PANAMA AND COSTA RICA NEAR THE 
ITCZ AXIS.

$$
BERG