000
AXPZ20 KNHC 230915
TWDEP 

TROPICAL WEATHER DISCUSSION
NWS NATIONAL HURRICANE CENTER MIAMI FL
1005 UTC SAT NOV 23 2013

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 0600 UTC SURFACE ANALYSIS AND SATELLITE IMAGERY THROUGH 
0900 UTC.

...SPECIAL FEATURES...

BUILDING HIGH PRESSURE IN THE WESTERN GULF OF MEXICO IN 
ASSOCIATION WITH AN ADVANCING COLD FRONT IS FORCING A GULF OF 
TEHUANTEPEC GAP WIND EVENT. FRESH TO STRONG NORTHERLY WINDS AND 
SEAS TO 8 FT ARE OCCURRING EVEN BEFORE THE ARRIVAL OF THE FRONT 
DUE TO A PRE-EXISTING NORTH-SOUTH PRESSURE GRADIENT. WINDS WILL 
INCREASE TO MINIMAL GALE FORCE BY 24 HOURS WITH RESULTANT SEAS 
BUILDING TO UP TO 13 FT. WINDS AND SEAS SHOULD DIMINISH/SUBSIDE 
AFTER SUNRISE MON. SEE LATEST NHC HIGH SEAS FORECAST UNDER 
AWIPS/WMO HEADERS MIAHSFEP2/FZPN03 KNHC FOR MORE DETAILS.

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

THE MONSOON TROUGH EXTENDS FROM 07N78W TO 10N86W TO 06N97W TO 
11N117W TO 08N120W. THE ITCZ EXTENDS FROM 08N120W TO BEYOND 
07N140W. SCATTERED MODERATE CONVECTION IS WITHIN 45 NM EITHER 
SIDE OF THE MONSOON TROUGH BETWEEN 104W AND 108W...AND ALSO 
WITHIN 120-150 NM EITHER SIDE OF THE MONSOON TROUGH BETWEEN 109W 
AND 112W.

SCATTERED MODERATE CONVECTION IS ALSO N OF 18N WITHIN 60 NM 
EITHER SIDE OF A SURFACE TROUGH WHICH EXTENDS FROM 22N107W TO 
17N111W.

...DISCUSSION...

A WEAKENING 1014 MB SURFACE LOW IS CENTERED AT 31N119W JUST WEST-
SOUTHWEST OF TIJUANA MEXICO. A COLD FRONT EXTENDS FROM THE LOW 
TO THE SOUTHEAST BENDING BACK TO THE SOUTHWEST ACROSS CENTRAL 
BAJA AND BACK OUT OVER THE PACIFIC OCEAN TO 20N120W. RECENT 
ASCAT SCATTEROMETER DATA INDICATED AN AREA OF FRESH TO STRONG 
WINDS IN THE FAR NW GULF OF CALIFORNIA N OF 30N W OF 114W. THESE 
WINDS SHOULD DIMINISH TO MODERATE TO FRESH LEVELS LATER THIS 
MORNING. THERE ARE NO WINDS STRONGER THAN A FRESH BREEZE IN 
ASSOCIATION WITH THE FRONT W OF THE BAJA PENINSULA...NOR IS 
THERE ANY SIGNIFICANT DEEP CONVECTION. A NORTHERLY SWELL BEHIND 
THE FRONT IS PRODUCING SEAS UP TO 11 FT. THIS SWELL IS FORECAST 
TO SUBSIDE TO LESS THAN 8 FT WITHIN THE NEXT 18 HOURS.
 
NE TRADEWINDS OVER THE W CENTRAL WATERS ARE DIMINISHING FROM 
FRESH TO MODERATE WITH RESULTANT SEAS NOW LESS THAN 8 FT.

A COLD FRONT CURRENTLY W OF 140W REACHING FROM 1011 MB LOW PRES 
NEAR 35N145W TO JUST S OF MAUI WILL GRADUALLY APPROACH THE FAR 
NW CORNER OF THE DISCUSSION WATERS. SOUTHERLY WINDS AHEAD OF THE 
FRONT WILL BE AT FRESH BREEZE LEVELS AND THE COMBINATION OF 
MIXED NE AND SE SWELL WILL RESULT IN COMBINED SEAS OF 8 FT 
BRIEFLY NEAR THE NORTHWEST BORDER OF THE AREA...COMMENCING BY 18 
HOURS...THEN SUBSIDING BY 36 HOURS AS THE COLD FRONT ENTERS THE 
AREA E OF 140W WHILE WEAKENING.

IN THE EXTENDED RANGE...THE NEXT SIGNIFICANT GULF OF TEHUANTEPEC 
GAP WIND EVENT WILL LIKELY COMMENCE LATE TUE NIGHT/EARLY WED 
THROUGH AT LEAST FRIDAY. EARLY PROJECTIONS ARE FOR IT TO REACH 
GALE OR STRONG GALE FORCE CONDITIONS. ALSO OVER THE NEXT SEVERAL 
DAYS...NO NEW SIGNIFICANT COLD FRONTS ARE ANTICIPATED IN OUR 
AREA.
 
THE GRIDDED WIND PREDICTION IS A BLEND OF THE PREVIOUS FORECAST 
WITH THE 00Z GFS MODEL...WITH THE WINDS ADJUSTED UP SLIGHTLY FOR 
THE LATTER IN ASSOCIATION WITH THE GULF OF TEHUANTEPEC EVENT. 
THE GRIDDED WAVE PREDICTION IS A BLEND OF THE PREVIOUS FORECAST 
WITH THE 00Z MULTI-GRID WAVEWATCH III MODEL.

$$
LEWITSKY