000
AXPZ20 KNHC 182155
TWDEP 

TROPICAL WEATHER DISCUSSION  
NWS TPC/NATIONAL HURRICANE CENTER MIAMI FL
2205 UTC SUN JAN 18 2009

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.

...ITCZ...
AXIS ALONG 04N77W TO 04N943W TO 04N105W TO 07N118W TO 08N125W TO 
06N140W. SCATTERED MODERATE CONVECTION WITHIN 90 NM N AND 60 NM 
S OF AXIS FROM 115W TO 128W. ISOLATED MODERATE CONVECTION 60 NM 
OF AXIS FROM 102W TO 115W. ISOLATED MODERATE TO DEEP CONVECTION 
60 NM OF AXIS FROM 89W TO 95W.

...DISCUSSION...
MAIN FEATURE ACROSS THE AREA IS AN ELONGATED AND DEEP LAYERED 
CYCLONIC CIRCULATION ALONG 122W BETWEEN 07N AND 30N. EMBEDDED 
VORTEX EARLIER TODAY HAS FILLED AND IS BEING EJECTED TO THE NE 
ATTM...WHILE ANOTHER VORTEX HAS FORMED NEAR THE SOUTHERN END 
NEAR 12.5N123W. RIDGING TO THE E CONTINUES TO BLOCK THIS TROUGH 
FROM MOVING FORWARD...BUT IS FORECAST TO BE NUDGED FORWARD TO 
ALONG 118W BY 48 HOURS AS MID LATITUDE UPPER TROUGH N OF THE 
HAWAIIAN ISLANDS APPROACHES THE W COAST OF THE U.S. DURING THE 
NEXT FEW DAYS. DEEP TROPICAL MOISTURE IS CURRENTLY BEING 
ADVECTED NWD ON THE E SIDE OF THE TROUGH BETWEEN 107W AND 
115W...RESULTING IN SCATTERED TO NUMEROUS MODERATE AND ISOLATED 
DEEP CONVECTION BEING ENHANCED DUE TO UPPER DIVERGENCE. AN 
ASSOCIATED 1014 MB SURFACE LOW CONTINUES THIS AFTERNOON NEAR 
17.5N128W WITH SEVERAL SMALL EMBEDDED MESO VORTICES ROTATING 
AROUND THE BROADER CIRCULATION. SCATTEROMETER WINDS EARLIER 
TODAY REVEALED 20 TO 25 K WINDS ACROSS THE N SEMICIRCLE. 
ISOLATED MODERATE CONVECTION WAS PERSISTING WITHIN 240 NM OF 
THIS SURFACE LOW. ACTIVE CONVECTION E OF THE DEEP LAYERED TROUGH 
IS FORECAST TO GRADUALLY DIMINISH OVER THE NEXT 24 TO 36 HOURS.

GAP WINDS...THE GULF OF TEHUANTEPEC GALE EVENT HAS EXPIRED BUT 
N-NE WINDS ARE EXPECTED TO REMAIN 20 TO 25 KT THROUGH 48 HRS AS 
HIGH PRES OVER GULF OF MEXICO DRIFTS E. 

GULF OF PAPAGAYO STRONG NE WINDS HAVE WEAKENED SOMEWHAT AND WILL 
FLUCTUATE UP AND DOWN DURING THE NEXT 48 HOURS...BUT GENERALLY 
REMAIN AT 20 KT OR GREATER. 

A STRONG COLD FRONT HAS ENTERED THE AREA FROM THE NW...EXTENDING 
SW INTO THE TROPICS S OF HAWAII. THE UPPER TROUGH MENTIONED 
ABOVE WILL SUPPORT A FURTHER E TO SE PROGRESS OF THIS FRONT 
DURING THE NEXT 48 HOURS...AND AS IT MOVES TO WITHIN 8-10 
DEGREES OF THE DEEP LAYERED TROUGH TO ITS SE BY 24 HOURS... 
MOISTURE AND ENERGY FROM THE DEEP LAYERED TROUGH WILL BE SHEARED 
N AND NE AND INDUCE ACTIVE CONVECTION ALONG THE FRONT N OF 20N.

SEVERAL PULSES OF LONG PERIOD NW SWELL ARE EXPECTED DURING THE 
NEXT SEVERAL DAYS. ONE PULSE CURRENTLY MOVING THROUGH THE MIDDLE 
OF THE AREA IS PRODUCING SEAS OF 8 FT AND GREATER ACROSS MOST OF 
THE AREA W OF 100W...WITH PEAK SEAS ACROSS THE AREA ARE 
CURRENTLY BEHIND THE FRONT AT 14 TO 18 FT...WHILE SEAS ACROSS 
THE N SEMICIRCLE OF THE 1014 MB LOW ARE RUNNING 10 TO 12 FT IN 
NW SWELL. THIS PULSE OF NW SWELL WILL REACH 90W BY 48 
HOURS...WHILE SEAS REMAIN 10 TO 15 FT W OF 127W AND N OF 15N 
THROUGH THAT PERIOD. 

$$
STRIPLING