000
AXPZ20 KNHC 220341
TWDEP 

TROPICAL WEATHER DISCUSSION 
NWS NATIONAL HURRICANE CENTER MIAMI FL 
0405 UTC SUN DEC 22 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 0000 UTC SURFACE ANALYSIS AND SATELLITE IMAGERY THROUGH 
0315 UTC.

...SPECIAL FEATURES...

GULF OF TEHUANTEPEC...THE NEXT GAP WIND EVENT IS EXPECTED TO 
BEGIN MON MORNING WITH N WINDS OF 20-30 KT...AND QUICKLY  
INCREASING TO GALE FORCE BEGINNING DURING THE AFTERNOON HOURS. 
WITH STRONG HIGH PRES RIDGING BUILDING SWD BEHIND A COLD FRONT 
THAT WILL MOVE ACROSS THE WESTERN GULF OF MEXICO LATE SUN INTO 
MON...THE RESULTANT PRES GRADIENT OVER SOUTHEASTERN MEXICO AND 
THE ISTHMUS OF TEHUANTEPEC WILL TIGHTEN CONSIDERABLY ALLOWING 
FOR THE STRONG NLY FLOW TO FUNNEL THROUGH THE CHIVELA PASS AND 
OUT ACROSS THE GULF. LATEST 30M AND 925 MB WIND GUIDANCE FROM 
THE GFS MODEL DEPICTS THIS NEXT EVENT TO REACH THE RANGE OF 30-
40 KT MON AFTERNOON...AND UP TO 45 KT MON EVENING. CANNOT RULE 
OUT POSSIBLE BRIEF GUSTS TO 50 KT. SEAS IN THE GULF WILL RAPIDLY 
BUILD TO 12 FT MON AFTERNOON...TO 10-17 FT MON NIGHT AND TO EVEN 
HIGHER VALUES OF 16-20 FT ON TUE. WITH THE FANNING OUT OF THE 
WINDS AWAY FROM THE GULF MON THROUGH TUE...EXPECT WINDS OF FRESH 
INTENSITY TO SPREAD TO NEAR 105W WITH SEAS TO 8 FT...AND SEAS TO 
10 FT TO REACH NEAR 100W.

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

THE MONSOON TROUGH AXIS EXTENDS FROM 06N78W TO 08N91W TO 07N106W 
...WHERE LOW LEVEL WINDS SUGGEST IT TRANSITIONS TO THE ITCZ 
WHICH EXTENDS TO 08N120W TO 09N130W AND TO BEYOND 09N140W. 
SCATTERED MODERATE/ISOLATED STRONG CONVECTION EXISTS WITHIN 60 
NM N OF THE ITCZ BETWEEN 128W-130W. SCATTERED MODERATE 
CONVECTION IS SEEN WITHIN 120 NM N OF THE ITCZ W OF 132W.

...DISCUSSION... 

A LARGE UPPER LEVEL RIDGE EXTENDS FROM NEAR 23N124W NW THROUGH 
32N129W AND TO A CREST TO WELL N OF THE DISCUSSION AREA. TO ITS 
E...BROAD UPPER TROUGHING COVERS THE AREA N OF 19N. A JET STREAM 
BRANCH EXTENDS FROM 17N140W E TO 18N130W THEN ENE TO 18N118W TO 
21N110W AND TO ACROSS CENTRAL MEXICO. A SHORTWAVE TROUGH IS 
EMBEDDED WITHIN JET STREAM ASSOCIATED WLY FLOW ROUGHLY FROM 
19N119W SE TO 14N116W TO NEAR 09N111W. OVERCAST TO BROKEN TO 
MULTILAYERED CLOUDS ARE S OF THE JET STREAM W OF 126W. BROKEN TO 
SCATTERED MAINLY HIGH LEVEL CLOUDS ARE WITHIN 390 NM S OF THE 
JET STREAM E OF THE SHORTWAVE TROUGH. SCATTERED MODERATE 
CONVECTION IS TO THE E OF THE SHORTWAVE TROUGH WITHIN 30 NM OF 
14N114.5W. WIDELY SCATTERED SHOWERS AND ISOLATED TSTMS ARE 
POSSIBLE UNDERNEATH THE AREA OF CLOUDINESS ASSOCIATED WITH THE 
JET STREAM BRANCH OUTSIDE CONVECTION RELATED TO THE ITCZ AS 
DESCRIBED ABOVE. SATELLITE WATER VAPOR IMAGERY SHOWS VERY DRY 
AIR COVERING THE AREA N OF 19N E OF ABOUT 135W...AND ALSO OVER 
THE EASTERN PORTION OF THE AREA TO THE SE THE JET STREAM 
MOISTURE/CLOUDINESS...WITH THE EXCEPTION OF SMALL PATCHES OF 
MOISTURE PRODUCING ISOLATED TSTMS ALONG THE MONSOON TROUGH 
BETWEEN 90W-99W. BROKEN TO SCATTERED STRATOCUMLUS CLOUDS IN THE 
DRY AND STABLE ATMOSPHERIC CONDITIONS ARE MOVING SSW WITH 
POSSIBLE ISOLATED SHOWERS N OF 19N E OF 135W. 

AT THE SURFACE...HIGH PRES OF 1032 MB IS CENTERED N OF THE AREA 
NEAR 39N139W WITH RIDGE EXTENDING SEWD THROUGH 32N132W AND TO 
NEAR 22N120W. THE PRES GRADIENT BETWEEN THE RIDGE AND LOWER 
PRESSURE IN THE VICINITY OF THE ITCZ IS MAINTAINING A SMALL AREA 
OF FRESH TO STRONG TRADES FROM 12N TO 17N W OF 132W. THE 1032 MB 
HIGH WILL MOVE NE THROUGH MON EVENING WITH ONLY SLIGHTLY 
WEAKENING ALLOWING FOR THE AREA OF FRESH TO STRONG TRADES TO 
ONLY SHRINK A LITTLE FROM E TO W.

LONG PERIOD NW SWELLS...WITH WAVE PERIODS BETWEEN 19-21 SEC 
ALONG THE LEADING EDGE...ARE MOVING ACROSS THE FAR NW PORTION OF 
THE FORECAST AREA. THESE SWELL WILL CONTINUE TO PROPAGATE SEWD  
COVERING MUCH OF THE FORECAST AREA W OF 110W BY MON MORNING. 
GUIDANCE SUGGESTS THAT THE LEADING EDGE OF THIS SWELLS TRAIN 
WILL CROSS THE EQUATOR W OF ABOUT 116W BY MON EVENING. 

GULF OF PAPAGAYO...NE WINDS FOR THE TIME BEING HAVE DIMINISHED 
TO 15-20 KT. HOWEVER...BY LATE TONIGHT THEY ARE EXPECTED TO 
BEGIN PULSING AGAIN...REACHING TO 20-25 KT BY DAYBREAK ON SUN AS 
NOCTURNAL DRAINAGE FLOW KICKS IN. THE WINDS ARE FORECAST TO 
DIMINISH AGAIN DURING MON AFTERNOON...AND MAYBE PULSE BRIEFLY 
EARLY ON MON BEFORE DIMINISHING AGAIN IN THE AFTERNOON. SHUTTING 
DOWN 

GULF OF CALIFORNIA...HIGH PRES WILL BUILD ACROSS THE GREAT BASIN 
REGION THROUGH MON WHILE INTENSIFYING. THE PRES GRADIENT BETWEEN 
THE HIGH PRES AND TROUGHING OVER MEXICO WILL STRENGTHEN WINDS 
OVER THE CENTRAL AND NRN GULF OF CALIFORNIA BY LATE SUN NIGHT 
WITH NW FLOW OF 20-25 KT. BY MON AFTERNOON AND INTO THE EVENING 
...THESE WINDS ARE FORECAST TO ENCOMPASS JUST ABOUT THE ENTIRE 
GULF WITH SEAS BUILDING TO AROUND 6 FT. 
 
$$
AGUIRRE