381
AXPZ20 KNHC 170937
TWDEP
TROPICAL WEATHER DISCUSSION
NWS NATIONAL HURRICANE CENTER MIAMI FL
1005 UTC THU APR 17 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 0600 UTC SURFACE ANALYSIS AND SATELLITE IMAGERY THROUGH
0820 UTC.
..SPECIAL FEATURE
GULF OF CALIFORNIA GALE WARNING: LOW PRESSURE OVER SOUTHERN
CALIFORNIA AND WESTERN ARIZONA EXTENDS SOUTHWARD INTO THE
NORTHERN GULF OF CALIFORNIA AND IS EXPECTED TO PERSIST THROUGH
FRI. HIGH PRESSURE IS WELL NW OF THE BAJA PENINSULA, AND EXTENDS
A WEAK RIDGE EASTWARD INTO THE BAJA SUR WATERS. THIS PATTERN IS
PRODUCING STRONG TO MINIMAL GALE-FORCE W TO SW GAP WINDS ACROSS
THE FAR NORTHERN GULF OF CALIFORNIA TONIGHT, TO THE SOUTH OF THE
LOW PRESSURE THERE. SEAS ARE ASSUMED TO HAVE BUILT TO NEAR 9 FT
THERE. WINDS ACROSS THE NORTHERN GULF WILL DIMINISH BELOW GALE-
FORCE BY SUNRISE, AND THEN TO 15 KT OR LESS BY AFTERNOON. THIS
PATTERN IS EXPECTED TO REPEAT ITSELF AGAIN THU NIGHT AND FRI
NIGHT, WITH THE PEAK WINDS AT NIGHT BECOMING PROGRESSIVELY
WEAKER EACH NIGHT. THE HIGH PRESSURE EXTENDS ACROSS BAJA AND
NORTHWESTERN MEXICO TONIGHT AHEAD OF A STRONG FRONTAL SYSTEM
DEVELOPING ACROSS THE WESTERN U.S., AND WILL ALSO INDUCE
WESTERLY GAP WINDS EACH OF THE NEXT FEW NIGHTS ACROSS CENTRAL
PORTIONS OF THE GULF, PEAKING AT STRONG SPEEDS.
..INTERTROPICAL CONVERGENCE ZONE/MONSOON TROUGH
A SURFACE TROUGH EXTENDS FROM 09.5N75W TO 07N78W TO 08.5N85W TO
05N94W. THE ITCZ THEN EXTENDS FROM 05N94W TO 05N116W TO 02N137W.
A SOUTHERN HEMISPHERIC ITCZ IS ANALYZED FROM 00.5S95W TO
00.5S115W TO BEYOND 01.5S120W. SCATTERED MODERATE TO STRONG
CONVECTION IS NOTED FROM 01S TO 08N E OF 90W. SCATTERED MODERATE
ISOLATED STRONG CONVECTION IS ELSEWHERE FROM 03N TO 08N BETWEEN
92W AND 128W.
..OFFSHORE WATERS WITHIN 250 NM OF MEXICO
SEE THE SPECIAL FEATURES SECTION INFORMATION ON AN NORTHERN
GULF OF CALIFORNIA GALE-FORCE GAP WIND EVENT.
A SURFACE RIDGE ACROSS THE EASTERN HALF OF THE GULF OF AMERICA
AND SOUTHEASTERN MEXICO CONTINUES TO SUPPORT STRONG N WINDS IN
THE GULF OF TEHUANTEPEC EXTENDING TO ABOUT 14N TONIGHT, WITH
MODERATE TO FRESH NE WINDS EXTENDING FARTHER SOUTH TO ABOUT 10N.
PEAK SEAS ARE NEAR 9 FT. DEEP LAYERED LOW PRESSURE OFFSHORE OF
SOUTHERN CALIFORNIA IS PRODUCING A WEAK SURFACE LOW THERE, WITH
AN ELONGATED TROUGH EXTENDING SOUTHWESTWARD TO NEAR 27N131W.
THIS AREA OF LOW PRESSURE IS BLOCKING HIGH PRESSURE FARTHER NW
FROM BUILDING UNOBSTRUCTED INTO THE BAJA WATERS. HOWEVER, THIS
HIGH PRESSURE DOES EXTEND A WEAK RIDGE EASTWARD AND BELOW THE
SURFACE TROUGH TO BAJA SUR. THE ASSOCIATED PRESSURE GRADIENT
BETWEEN THIS RIDGE AND LOWER PRESSURE ACROSS THE GULF OF
CALIFORNIA IS SUPPORTING GENTLE WINDS ACROSS THE WATERS OF
BAJA NORTE, AND MODERATE TO LOCALLY FRESH NNW WINDS ACROSS THE
BAJA WATERS SOUTH OF PUNTA EUGENIA BECOMING NORTHERLY ACROSS THE
REVILLAGIGEDO ISLANDS. SEAS ARE 4 TO 5 FT N OF PUNTA EUGENIA AND
5 TO 7 FT SOUTHWARD TO THE REVILLAGIGEDO ISLANDS. GENTLE WINDS
PREVAIL ACROSS SOUTHERN PORTIONS OF THE GULF OF CALIFORNIA WITH
2 TO 4 FT SEAS. ELSEWHERE OVER THE PACIFIC OFFSHORE WATERS,
WINDS ARE MODERATE OR WEAKER WITH SEAS OF 4-5 FT IN MIXED NW AND
S SWELL.
FOR THE FORECAST, STRONG TO MINIMAL GALE-FORCE SW TO W GAP WINDS
OCCURRING OVER THE NORTHERN GULF OF CALIFORNIA LATE TONIGHT WILL
DIMINISH QUICKLY BY SUNRISE, AND THEN PULSE AGAIN TO STRONG TO
NEAR GALE-FORCE ON THU NIGHT. FRESH TO LOCALLY STRONG W GAP WINDS
WILL ALSO DEVELOP DURING THIS TIME ACROSS CENTRAL PORTIONS OF
THE GULF. STRONG NORTHERLY WINDS OVER THE GULF OF TEHUANTEPEC
WILL CONTINUE OVERNIGHT THEN GRADUALLY DIMINISH THU, BEFORE THE
GAP WIND FLOW ENDS THERE THU NIGHT. ELSEWHERE, WINDS ACROSS THE
MEXICAN OFFSHORE ZONES WILL REMAIN MODERATE OR WEAKER NORTH OF
PUNTA EUGENIA, AND MODERATE TO FRESH OFF BAJA CALIFORNIA SUR
THROUGH SAT NIGHT, THEN BECOME MODERATE TO LOCALLY FRESH N OF 20N
SUN AFTERNOON THROUGH MON.
...OFFSHORE WATERS WITHIN 250 NM OF CENTRAL AMERICA, COLOMBIA,
AND WITHIN 750 NM OF ECUADOR...
HIGH PRESSURE ACROSS THE CENTRAL ATLANTIC AND EASTERN GULF OF
AMERICA EXTENDING INTO THE NW CARIBBEAN IS INDUCING GAP WINDS
ACROSS THE PACIFIC WATERS OF CENTRAL AMERICA, AND FRESH TO
LOCALLY STRONG NE TO E GAP WINDS ACROSS THE PAPAGAYO REGION
TONIGHT. SEAS ARE CURRENTLY 5 TO 8 FT THERE. NE WINDS ACROSS THE
SW CARIBBEAN ARE INDUCING FRESH N WINDS OVER THE GULF OF PANAMA
EXTENDING TO 06N, WHERE SEAS ARE 4 TO 6 FT. ELSEWHERE, BETWEEN
ECUADOR AND THE GALAPAGOS ISLANDS, WINDS ARE GENTLE TO MODERATE
WITH 4-6 FT SEAS IN S SWELL. SCATTERED HEAVY SHOWERS AND STRONG
THUNDERSTORMS CONTINUE TO SHIFT WESTWARD ACROSS THE WATERS S OF
08N, MOVING OFFSHORE NORTHERN ECUADOR AND COLOMBIA AND PASSING
ALONG THE PACIFIC COASTS AND WATERS OF PANAMA AND COSTA RICA E OF
90W. STRONG CONVECTION THERE HAS THE POTENTIAL TO PRODUCE WIND
GUSTS TO GALE FORCE AND LOCALLY ROUGH SEAS.
FOR THE FORECAST, THE SURFACE RIDGE OVER THE EASTERN GULF OF
AMERICA EXTENDING INTO THE NW CARIBBEAN WILL SHIFT GRADUALLY
EASTWARD TO THE ATLANTIC WATERS BETWEEN CAPE HATTERAS AND BERMUDA
DURING THE NEXT SEVERAL DAYS TO SUPPORT FRESH TO STRONG NE TO E
GAP WINDS ACROSS THE PAPAGAYO REGION, PULSING TO NEAR 30 KT AT
NIGHT THROUGH SAT NIGHT, THEN DIMINISH SLIGHTLY THROUGH MON
NIGHT. THE SAME HIGH PRESSURE WILL FORCE MODERATE TO FRESH N
WINDS ACROSS THE GULF OF PANAMA TO 4.5N THROUGH SAT NIGHT WITH
PEAK SEAS AROUND 6 FT. LOCALLY STRONG N TO NE WINDS ARE EXPECTED
IN THE GULF OF PANAMA THU NIGHT AND FRI NIGHT. MODERATE SW SWELL
WILL MOVE INTO THE REGIONAL WATERS MON.
..REMAINDER OF THE AREA.
A MODEST SURFACE RIDGE DOMINATES THE WATERS W OF 130W TONIGHT,
AND EXTENDS A RIDGE SOUTH THEN WEAKLY EASTWARD OVER THE
SUBTROPICAL WATERS W OF THE BAJA CALIFORNIA SUR WATERS, TO THE
SOUTH OF A SURFACE TROUGH EXTENDING FROM OFFSHORE OF SOUTHERN
CALIFORNIA TO NEAR 27N131W. ANOTHER SURFACE TROUGH IS JUST N OF
THE ITCZ FROM 10N137W TO 19N131W. THIS PATTERN CONTINUES TO
PRODUCE MODERATE TO LOCALLY FRESH NE WINDS BETWEEN THE ITCZ AND
21N, W OF 125W PER OVERNIGHT SCATTEROMETER DATA. SEAS IN THIS
REGION ARE 7-8 FT IN N SWELL. N OF 21N, GENTLE TO MODERATE N TO
NE WINDS PREVAIL, WITH SEAS OF 5 TO 7 FT IN MIXED NW AND NE
SWELL. S OF 20N BETWEEN 100W AND 125W, MODERATE TO LOCALLY FRESH
TRADE WINDS PREVAIL, WITH SEAS OF 5 TO 8 FT IN MIXED N AND E
SWELL. SCATTERED MODERATE ISOLATED STRONG CONVECTION IS
OCCURRING NEAR THE ITCZ TO 08N.
FOR THE FORECAST, LITTLE CHANGE IN THE WINDS ACROSS THE OPEN
WATERS IS EXPECTED FOR THE NEXT SEVERAL DAYS, EXCEPT FOR SLIGHTLY
STRONGER TRADES OCCURRING W OF 120W OVER THE WEEKEND. THE
PERSISTENCE OF THESE WINDS WILL LEAD TO BUILDING SEAS OF 8 TO 9
FT, SUBSIDING MON. OTHERWISE, NEW MODERATE NORTHERLY SWELL IS
FORECAST TO REACH OUR NORTHERN BORDER W OF THE BAJA CALIFORNIA
PENINSULA MON, BUILDING SEAS TO AROUND 8 FT.
STRIPLING
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