104
AXPZ20 KNHC 181525
TWDEP
TROPICAL WEATHER DISCUSSION
NWS NATIONAL HURRICANE CENTER MIAMI FL
1605 UTC THU DEC 18 2025
TROPICAL WEATHER DISCUSSION FOR THE EASTERN PACIFIC OCEAN FROM
03.4S TO 30N, EAST OF 120W INCLUDING THE GULF OF CALIFORNIA, AND
FROM THE EQUATOR TO 30N, BETWEEN 120W AND 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
THE MONSOON TROUGH EXTENDS FROM THE COAST OF PANAMA FROM 09N78W
TO 09N112W. THE ITCZ CONTINUES FROM 09N112W TO BEYOND 07N140W.
SCATTERED MODERATE CONVECTION IS NOTED FROM 06N-13N BETWEEN
92W-115W.
..OFFSHORE WATERS WITHIN 250 NM OF MEXICO
A 1023 MB HIGH CENTER IS ANALYZED N OF THE AREA NEAR 33N130W
WITH THE ASSOCIATED RIDGE EXTENDING TO NEAR THE REVILLAGIGEDO
ISLANDS. THE RELATED PRESSURE GRADIENT IS ALLOWING FOR GENTLE TO
MODERATE NORTHWEST TO NORTH WINDS AND SLIGHT TO MODERATE SEAS
OVER THE MEXICAN OFFSHORE WATERS INCLUDING THE GULF OF
CALIFORNIA. IN THE FAR OUTER BAJA CALIFORNIA NORTE WATERS AND
BEYOND, FRESH NW WINDS AND ROUGH SEAS ARE PRESENT DUE TO A TIGHT
PRESSURE GRADIENT MAINLY N OF THE AREA WITH A HIGH PRESSURE
INLAND OF THE SAN FRANCISCO BAY AREA AND TROUGHING JUST TO THE S
OVER THE CHANNEL ISLANDS.
FOR THE FORECAST, WITH A WEAK PRESSURE GRADIENT PREVAILING,
WINDS ACROSS FORECAST WATERS SHOULD REMAIN MODERATE OR WEAKER
THROUGH TOMORROW MORNING. BY FRI AFTERNOON, A TEHUANTEPECER GAP
WIND EVENT WILL BEGIN WITH FRESH TO NEAR GALE N TO NE WINDS.
WHILE NOT EXPECTED AT THIS TIME TO REACH GALE FORCE, THESE GAP
WINDS WILL BE PERSISTENT AND SHOULD CONTINUE FRESH TO NEAR GALE
OVER THE GULF OF TEHUANTEPEC THROUGH EARLY NEXT WEEK. ELSEWHERE,
WINDS AND SEAS SHOULD REMAIN QUIESCENT FOR THE NEXT SEVERAL DAYS.
...OFFSHORE WATERS WITHIN 250 NM OF CENTRAL AMERICA, COLOMBIA,
AND WITHIN 750 NM OF ECUADOR...
FRESH NE WINDS PREVAIL IN THE GULF OF PAPAGAYO EXTENDING DOWNWIND
TO NEAR 09N92W WITH AS HIGH PRESSURE OVER NORTHERN CENTRAL
AMERICA AND LOWER PRESSURES ALONG THE MONSOON TROUGH OVER
SOUTHERN COSTA RICA AND PANAMA. LIGHT TO GENTLE WINDS AND
MODERATE SEAS ARE ELSEWHERE N OF 06N. S OF 06N, GENTLE TO
MODERATE SOUTHERLY WINDS AND MODERATE SEAS PREVAIL PER EARLIER
ASCAT SCATTEROMETER DATA, EXCEPT SLIGHT SEAS NEARSHORE COLOMBIA,
EASTERN PANAMA, AND SOUTHERN COSTA RICA. SCATTERED SHOWERS ARE
PRESENT OFFSHORE COLOMBIA NORTHWARD.
FOR THE FORECAST, A LIGHT PRESSURE GRADIENT WILL CONTINUE TO
FORCE MODERATE OR WEAKER WINDS ACROSS FORECAST WATERS THROUGH
FRI. BUILDING HIGH PRESSURE OVER CENTRAL AMERICA WILL DRIVE FRESH
TO LOCALLY STRONG NE WINDS MAINLY DURING LATE NIGHT/EARLY
MORNING HOURS OVER THE GULF OF PAPAGAYO REGION FROM FRI EVENING
THROUGH AT LEAST EARLY NEXT WEEK. ELSEWHERE, WINDS AND SEAS WILL
BE QUIESCENT.
..REMAINDER OF THE AREA
A 1023 MB HIGH CENTER IS ANALYZED JUST N OF THE AREA NEAR
33N130W WITH THE ASSOCIATED RIDGE EXTENDING TO NEAR THE
REVILLAGIGEDO ISLANDS. THE PRESSURE GRADIENT BETWEEN THE HIGH AND
RELATIVELY LOWER PRESSURES NEAR THE ITCZ/MONSOON TROUGH IS
BRINGING MODERATE TO FRESH TRADE WINDS FROM 07N TO 22N AND W OF
120W, WHERE SEAS ARE 6-8 FT. A TIGHT PRESSURE GRADIENT OVER
SOUTHERN CALIFORNIA AND OFFSHORE SUPPORTS FRESH TO STRONG WINDS
AND ROUGH SEAS EXTENDING OVER OUR WATERS N OF 28N AND E OF 126W.
GENTLE TO MODERATE WINDS AND MODERATE SEAS PREVAIL ACROSS THE
REMAINDER OF THE OPEN WATERS, INCLUDING S OF THE MONSOON TROUGH
AND ITCZ.
FOR THE FORECAST, HIGH PRESSURE WILL CONTINUE OVER THE NORTHERN
WATERS TODAY LEADING TO FRESH EASTERLY WINDS AND ROUGH SEAS OVER
MUCH OF THE TRADEWIND BELT WEST OF 120W. A TIGHT PRESSURE
GRADIENT WILL PERSIST OVER AND OFFSHORE SOUTHERN CALIFORNIA
LEADING TO FRESH TO STRONG WINDS AND ROUGH SEAS IN THE N-CENTRAL
WATERS THROUGH THE REMAINDER OF THE WORK WEEK. MARINE CONDITIONS
SHOULD IMPROVE OVERALL DURING THE UPCOMING WEEKEND AS THE
PRESSURE GRADIENT SLACKENS DUE TO A COLD FRONT APPROACHING
30N140W. THIS FRONT MAY MOVE SE INTO THE NW AND N-CENTRAL WATERS
EARLY NEXT WEEK WITH THE POTENTIAL FOR FRESH TO STRONG NE WINDS
AND ROUGH SEAS BEHIND IT.
LANDSEA/RIVERA
CLICK HERE TO GO TO PREVIOUS BULLETINS.
Main Text Page