000
AXPZ20 KNHC 211602
TWDEP 

TROPICAL WEATHER DISCUSSION 
NWS NATIONAL HURRICANE CENTER MIAMI FL
1605 UTC WED NOV 21 2012

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 1200 UTC SURFACE ANALYSIS AND SATELLITE IMAGERY THROUGH 
1500 UTC.

...INTERTROPICAL CONVERGENCE ZONE/MONSOON TROUGH...

MONSOON TROUGH EXTENDS FROM 07N77W TO 09N85W TO 06N93W...WHERE 
THE TROUGH TRANSITIONS TO ITCZ...CONTINUING ON 09N120W TO BEYOND 
07N140W. SCATTERED TO NUMEROUS MODERATE AND STRONG CONVECTION 
NOTED N OF 05N E OF 85W. SCATTERED MODERATE ISOLATED STRONG 
CONVECTION NOTED WITHIN 90 NM EITHER SIDE OF THE ITCZ W OF 115W.

...DISCUSSION...

A GALE-FORCE GAP WIND EVENT CONTINUES IN THE GULF OF TEHUANTEPEC 
THIS MORNING.  FUNNELING OF WINDS THROUGH THE CHIVELAS PASS IS 
ONGOING AS INDICATED BY THE 20 KT N WIND AT SALINA CRUZ MEXICO.  
WITHIN THE GULF OF TEHUANTEPEC...A 0638 UTC OSCAT SCATTEROMETER 
PASS INDICATED NUMEROUS 35 KT WIND VECTORS EARLIER THIS MORNING.
ALL GUIDANCE INDICATES THAT NEAR GALE TO GALE CONDITIONS WILL 
REMAIN THROUGH THURSDAY MORNING...THEN MODERATE TO BELOW GALE 
CONDITIONS BRIEFLY LATE THURSDAY AND FRIDAY.  GALES IN 
TEHUANTEPEC MAY AGAIN RESUME ON SATURDAY AND SUNDAY AS HIGH 
PRESSURE REBUILDS IN THE GULF OF MEXICO. SHORT-PERIOD...8-10 
SECOND...NE WAVES WITH SIGNIFICANT WAVE HEIGHTS OF UP TO 12 FEET 
WILL OCCUR IN THE GULF OF TEHUANTEPEC THROUGH TOMORROW MORNING 
BEFORE MODERATING SOME LATE THURSDAY AND FRIDAY.

ANOTHER GAP WIND EVENT IN THE GULF OF PAPAGAYO IS PRODUCING 
STRONG BREEZE CONDITIONS.  THIS EVENT SHOULD CONTINUE FOR THE 
NEXT COUPLE OF DAYS WITH LITTLE CHANGE...BUT WITH THE TYPICAL 
DIURNAL VARIABILITY WITH WEAKER WINDS AND LOWER SEAS DURING THE 
AFTERNOON AND EARLY EVENING. FORCING FOR THIS EVENT SHOULD 
SUBSIDE BELOW OUR 25 KT CRITERION BY MONDAY.

IT IS OF NOTE THAT IN THE NEXT DAY OR SO...THE GLOBAL FORECAST 
SYSTEM AND ASSOCIATED WAVEWATCH MODEL GUIDANCE INDICATES AN 
ENHANCEMENT OF THE SW WINDS AND WAVES IN THE GULF OF PANAMA TO 
STRONG BREEZE AND 8 FOOT CONDITIONS.  IT APPEARS THAT THIS MAY 
BE DUE TO SOME ERRONEOUS CONVECTIVE FEEDBACK IN THE MODEL...AS 
NONE OF THE REMAINING GUIDANCE INDICATES THIS.  THUS HIGH WINDS 
AND SEAS ARE NOT INDICATED IN THE FORECAST FOR THE GULF OF 
PANAMA.

LONG-PERIOD...13-15 SECOND...NW SWELL WITH SIGNIFICANT WAVE 
HEIGHTS OF UP TO 12 FEET ARE OCCURRING IN OUR NW AREA OF 
RESPONSIBILITY DUE TO FORCING FROM A WINTER STORM SOUTH OF 
ALASKA.  THIS NW SWELL WILL BE PUSHING SOUTHEASTWARD AND 
GRADUALLY DIMINISHING OVER THE NEXT COUPLE OF DAYS. THE NEXT 
NOTEWORTHY LONG-PERIOD SWELL EVENT MAY OCCUR BEGINNING NEXT 
WEDNESDAY.

THE FLAREUPS OF CONVECTIVE ACTIVITY WEST OF 115W AND E OF 85W 
ASSOCIATED WITH THE ITCZ AND MONSOON TROUGH...RESPECTIVELY...ARE 
NOT ANTICIPATED TO DEVELOP INTO LATE SEASON TROPICAL CYCLONES.

$$
LANDSEA