000
AXPZ20 KNHC 281006
TWDEP 

TROPICAL WEATHER DISCUSSION
NWS NATIONAL HURRICANE CENTER MIAMI FL 
1005 UTC SAT NOV 28 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 0600 UTC SURFACE ANALYSIS AND SATELLITE IMAGERY THROUGH
0945 UTC.               

...SPECIAL FEATURES...

TROPICAL STORM SANDRA IS CENTERED NEAR 21.4N 109.2W AT 0900
UTC...OR ABOUT 97 NM SSE OF CABO SAN LUCAS MEXICO...MOVING N AT
2 KT. ESTIMATED MINIMUM CENTRAL PRESSURE IS 1000 MB. MAXIMUM
SUSTAINED WIND SPEED HAS DECREASED TO 35 KT WITH GUSTS TO 45 KT.
STRONG SOUTHWESTERLY UPPER LEVEL WIND SHEAR MAINTAIN THE
CONVECTION ASSOCIATED WITH SANDRA INLAND W CENTRAL MEXICO.
SANDRA IS EXPECTED TO CONTINUE TO WEAKEN QUICKLY THROUGH
SATURDAY AS THE HOSTILE UPPER LEVEL WIND SHEAR IS FORECAST TO
INCREASE. DETERIORATING MARINE CONDITIONS SHOULD BE EXPECTED
ACROSS THE SOUTH HALF OF THE GULF OF CALIFORNIA TODAY AS
SOUTHERLY SWELL GENERATED BY SANDRA MOVES INTO THE LOWER TWO-
THIRDS OF THE GULF...AND COMBINES WITH THE TROPICAL STORM FORCE
WINDS OF SANDRA. SEE LATEST NHC FORECAST ADVISORY UNDER
AWIPS/WMO HEADERS MIATCMEP2/WTPZ22 NHC FOR MORE DETAILS.
 
GULF OF TEHUANTEPEC...STRONG HIGH PRESSURE ACROSS THE EASTERN
SEABOARD OF THE U.S. SHIFTING SLIGHTLY SW TODAY IS ALLOWING THE
INCREASE OF GAP WIND FLOW ACROSS CENTRAL AMERICA DURING THE
WEEKEND...THUS SUPPORTING GALE FORCE WINDS LIKELY
CONTINUING THROUGH MONDAY MORNING.

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

THE MONSOON TROUGH EXTENDS FROM 04N77W TO 04N87W TO
05N96W...WHERE IT REMAINS FRACTURED...THEN RESUMES NEAR 11N112W
TO 06N120W TO 05N124W...WHERE IT TRANSITIONS TO
ITCZ...CONTINUING ON 03N132W TO BEYOND 03N140W. SCATTERED
MODERATE CONVECTION IS FROM 02N TO 07N E OF 89W...FROM 05N TO
10N BETWEEN 113W AND 118W AND FROM 04N TO 10N BETWEEN 126W AND
131W.

...DISCUSSION...                                           
A COLD FRONTAL BOUNDARY THAT MOVED THROUGH BAJA CALIFORNIA AND
MOST OF THE EASTERN WATERS THE PAST FEW DAYS MERGED ACROSS
CENTRAL PORTIONS WITH THE REMNANTS OF FORMER TROPICAL CYCLONE
RICK. A STRONG PRESSURE GRADIENT BETWEEN HIGH PRESSURE TO THE
NORTH AND THIS MERGED FEATURES IS SUPPORTING A BROAD BAND OF
FRESH TO STRONG NE WINDS FROM GENERALLY 15N TO 21N W OF 126W
...WITH COMBINED SEAS OF 11 TO 13 FT PREVAILING IN MIXED NW
SWELL AND NE WIND WAVES. ELSEWHERE THIS LONG PERIOD NW SWELL IS
MIXING WITH NE WIND WAVES AND SE SWELL FROM SANDRA... RESULTING
IN CONFUSED SEAS OF 8 TO 11 FT GENERALLY FROM 10N TO 29N W OF
111W. THE AREA OF FRESH TO STRONG TRADES IS EXPECTED TO SHIFT
WEST-SOUTHWESTWARD AS RIDGING BUILDS SOUTHEASTWARD ACROSS THE
NORTHERN FORECAST WATERS THROUGH SUN. BY SUN THE AREA OF TRADES
WEAKENS AND SHRINKS IN AREAL COVERAGE...WHILE 8 TO 11 FT
COMBINED SEAS ARE FORECAST TO PREVAIL W OF 115W. A NEW COLD
FRONT WILL ENTER THE NW FORECAST WATERS MONDAY MORNING WITH NW
SWELL W OF THE BOUNDARY REACHING UP TO 13 FT.

GAP WINDS... 
AS MENTIONED ABOVE...THE GAP WIND FLOW ACROSS CENTRAL AMERICA
AND INTO THE EASTERN PACIFIC HAS INCREASED AND WILL CONTINUE
THROUGH THE WEEKEND AS HIGH PRESSURE BUILDS ACROSS THE GULF OF
MEXICO AND THE NW CARIBBEAN. NORTHEAST WINDS WILL BLOW ACROSS
AND DOWNSTREAM OF THE GULF OF PAPAGAYO FOR THE NEXT FEW
DAYS...WITH PULSES OF 20 TO 25 KT. LOOK FOR OTHER GAP WIND PRONE
AREAS SUCH AS THE GULF OF FONSECA TO ALSO REACH NEAR 20 KT EACH
NIGHT AND EARLY MORNING THROUGH MONDAY.
 
$$
NR