000
AXPZ20 KNHC 011531
TWDEP 

TROPICAL WEATHER DISCUSSION                                  
NWS NATIONAL HURRICANE CENTER MIAMI FL                      
1605 UTC TUE DEC 01 2015

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
1330 UTC.               

...SPECIAL FEATURE... 

GULF OF TEHUANTEPEC GALE WARNING...GALE CONDITIONS ARE EXPECTED
IN THE GULF OF TEHUANTEPEC BEGINNING AT THE END OF THE FORECAST
PERIOD ON THU MORNING. UNCERTAINTY IS SOMEWHAT HIGH ON THE
ONSET OF THE EVENT AS THE GLOBAL MODEL GUIDANCE DIFFERS ON THE
STRENGTH AND TIMING OF A COLD FRONT EXPECTED TO MOVE THROUGH THE
GULF OF MEXICO AND THROUGH CHIVELA PASS. THE FORECAST...WHICH
CALLS FOR MINIMAL GALE FORCE WINDS BY THE TIME OF PEAK NOCTURNAL
DRAINAGE FLOW...IS A COMPROMISE BETWEEN THE MORE RELIABLE GLOBAL
MODELS. THE 1104 UTC RAPIDSCAT PASS THIS MORNING SHOWED WINDS TO
30 KT HERE...BUT THESE WINDS SHOULD WEAKEN A NOTCH AFTER SUNRISE
TODAY AND DIMINISH BELOW THE ADVISORY CRITERIA OF 20-25 KT BY
WED AFTERNOON. N WINDS WILL AGAIN PICK UP TO ADVISORY CRITERIA
EARLY THU MORNING AS THE FRONT REACHES CHIVELA PASS...WITH WINDS
INCREASING TO GALE FORCE BEFORE SUNRISE. 

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

THE ITCZ AXIS WAS ANALYZED FROM 05N92W TO 06N97W TO 04N114W TO
06N125W...THEN CONTINUES FROM 07N130W TO 02N140W. SCATTERED
MODERATE CONVECTION WAS WITHIN 120 NM EITHER SIDE OF THE AXIS
BETWEEN 113W-120W AS WELL AS WITHIN 45 NM N AND 90 NM S OF THE
AXIS BETWEEN 105W-110W. 

...DISCUSSION... 

THE PRESSURE GRADIENT BETWEEN 1025 MB HIGH PRESSURE NEAR 32N129W
AND A SURFACE TROUGH FROM 11N127W TO 03N127W IS GENERATING A
LARGE AREA OF FRESH TO STRONG NE TRADE WINDS W OF 123W S OF 20N
TO A LINE FROM 13N123W TO 07N140W. SCATTERED MODERATE CONVECTION
WAS WITHIN 300 NM EITHER SIDE OF THE TROUGH FROM 06N-11N AND
WITHIN 300 NM E OF TROUGH FROM 03N-06N. THE TROUGH IS EXPECTED
TO REMAIN A FOCUS FOR CONVECTION AS IT SHIFTS W TO 140W BY THE
END OF THE FORECAST PERIOD THU MORNING. THE AREA OF FRESH TO
STRONG TRADES WILL SHIFT W WITH THE TROUGH AND SHOULD BE
CONFINED FROM 10N-17N W OF 135W BY THU MORNING. THE HIGH
PRESSURE SYSTEM WILL REMAIN RELATIVELY UNCHANGED THROUGH WED
NIGHT BEFORE WEAKENING IN ADVANCE OF A COLD FRONT EXPECTED TO
MOVE INTO THE NW WATERS LATE WED. 20-30 KT WINDS ARE EXPECTED
NEAR THE FRONT AS IT ENTERS THE FORECAST AREA. THESE WINDS WILL
DIMINISH TO A FRESH TO STRONG BREEZE N OF 29N BY THU MORNING
WHEN THE FRONT IS EXPECTED TO REACH FROM 30N130W TO 25N140W.
SEAS WILL BUILD AS HIGH AS 16-18 FT IN THE FAR NW CORNER IN LONG-
PERIOD NW SWELL BY WED NIGHT. 

GAP WINDS... 

GULF OF CALIFORNIA...A STRONG PRESSURE GRADIENT BETWEEN THE
GREAT BASIN OF THE UNITED STATES AND TROUGHING ALONG THE WESTERN
SLOPES OF THE SIERRA MADRE OCCIDENTAL WILL CHANGE LITTLE OVER
THE NEXT TWO DAYS. N-NW WINDS TO NEAR GALE FORCE WILL PERSIST
ALONG MUCH OF THE LENGTH OF THE GULF OF CALIFORNIA THROUGH AT
LEAST THU MORNING AS A RESULT. AN 0706 UTC ALTIMETER PASS SHOWED
SEAS TO 10 FT IN THE CENTRAL GULF. SEAS IN THE 8-10 FT RANGE
SHOULD CONTINUE PRIMARILY S OF 28N THROUGH THU MORNING. 

GULF OF PAPAGAYO...A LAST GASP OF 20-25 KT E-NE WINDS IN THE
GULF OF PAPAGAYO THIS MORNING IS EXPECTED TO DIMINISH AFTER
SUNRISE TODAY AS THE PRESSURE GRADIENT WEAKENS BETWEEN THE ITCZ
TO THE S AND HIGH PRESSURE NE OF THE AREA THAT IS SHIFTING E
INTO THE CENTRAL ATLC.
 
$$
SCHAUER