Tropical Weather Discussion
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000
AXPZ20 KNHC 260930
TWDEP

TROPICAL WEATHER DISCUSSION
NWS NATIONAL HURRICANE CENTER MIAMI FL
1005 UTC WED NOV 26 2014

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
0900 UTC.

...SPECIAL FEATURE...

GULF OF TEHUANTEPEC STORM WARNING...A STRONG HIGH PRES IN THE
WAKE OF A COLD FRONT...CURRENTLY MOVING ACROSS THE YUCATAN
PENINSULA IS PRODUCING A TIGHT PRESSURE GRADIENT ACROSS THE
ISTHMUS OF TEHUANTEPEC. THE EDGE OF AN 0352 UTC ASCAT PASS
CAPTURED SEVERAL WIND BARBS OF 30-35 KT NLY WINDS ACROSS THE
GULF OF TEHUANTEPEC WHILE A SHIP CALL SIGN A8EH5 LOCATED NEAR
13.5N95W REPORTED SEAS TO 10 FT. WINDS ARE EXPECTED TO QUICKLY
INCREASE TO STORM FORCE BY SUNRISE TODAY. STORM FORCE WINDS ARE
EXPECTED TO PERSIST THROUGH THU MORNING...DIMINISH TO GALE FORCE
THU AFTERNOON...THEN BELOW GALE CONDITIONS SAT AFTERNOON. WAVE
MODEL GUIDANCE INDICATES SEAS BUILDING TO 20-23 FT WITH NE SWELL
GREATER THAN 8 FT PROPAGATING WELL DOWNSTREAM FROM ITS GULF OF
TEHUANTEPEC SOURCE REGION.

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

MONSOON TROUGH EXTENDS FROM 10N85W TO 10N95W TO 09N110W. ITCZ
CONTINUES FROM 09N110W TO 11N116W THEN RESUMES FROM 10N121W TO
08N140W. CLUSTERS OF MODERATE TO ISOLATED STRONG CONVECTION ARE
NOTED N OF 07N BETWEEN 81W AND 84.5W TO THE COAST OF WESTERN
PANAMA AND SE COSTA RICA. SIMILAR CONVECTION IS WITHIN 45 NM S
OF TROUGH BETWEEN 86W AND 87W...AND FROM 09N TO 13N BETWEEN 116W
AND 121W.

...DISCUSSION...

GULF OF CALIFORNIA...THE MOST RECENT SCATTEROMETER DATA SHOWED
20-25 KT NW-N WINDS FROM 23N-29N IN THE GULF OF CALIFORNIA WITH
THESE WINDS EXTENDING FARTHER SOUTH TO 21N BETWEEN 108W AND
110W. AN ALTIMETER PASS INDICATED SEAS TO 9 FT IN ASSOCIATION
WITH THESE WINDS. A TIGHT PRESSURE GRADIENT EXISTS DUE TO A
TROUGH ALONG THE EASTERN GULF OF CALIFORNIA AND RIDGING NOSING
DOWN THE WEST COAST OF BAJA CALIFORNIA. WINDS WILL DIMINISH TO
20 KT OR LESS BY LATE THU MORNING. SEAS TO 9 FT IN THE SOUTHERN
GULF WILL SUBSIDE TO LESS THAN 8 FT BY LATE TODAY. AN AREA OF
FRESH TO STRONG NE WINDS PERSISTS JUST W OF BAJA CALIFORNIA...
PARTICULARLY FROM 24N TO 28N E OF 122W WITH SEAS OF 8-12 FT
ACCORDING TO AN ALTIMETER PASS. THESE WINDS WILL DIMINISH TO 20
KT OR LESS BY THIS MORNING AS THE PRESSURE GRADIENT SLACKENS
WITH SEAS GRADUALLY SUBSIDING TO AROUND 9 FT.

A 1026 MB HIGH PRES LOCATED N OF THE DISCUSSION AREA NEAR
34N125W EXTENDS A RIDGE ACROSS THE NORTH WATERS. THE PRESSURE
GRADIENT BETWEEN THE RIDGE AND LOWER PRESSURE ASSOCIATED WITH
THE ITCZ IS SUPPORTING FRESH TO LOCALLY STRONG TRADES ACROSS THE
WATERS W OF 120W. SCATTEROMETER DATA CONFIRMED THE PRESENCE OF
THESE WINDS.

FRESH TO STRONG S WINDS ARE OCCURRING IN THE FAR NW CORNER AHEAD
OF A COLD FRONT APPROACHING THE AREA. WINDS WILL DIMINISH AS THE
FRONT WEAKENS AND MOVES SLOWLY INTO THE FORECAST AREA THIS
MORNING. ASSOCIATED NW SWELL TO 12 FT WILL COVER THE AREA W OF A
LINE FROM 30N132W TO 20N138W BY EARLY THU MORNING.

A WEAK SURFACE TROUGH EMBEDDED WITHIN THE ITCZ EXTENDS FROM
15N116W TO 10N119W. NE WINDS IN THE 20-25 KT RANGE WITH SEAS TO
9 FT ARE NOTED W OF THE TROUGH AXIS TO ABOUT 125W. THE TROUGH
WILL CONTINUE TO MOVE WESTWARD WITH THE ASSOCIATED MARINE
CONDITIONS DURING THE NEXT 24 HOURS.

MIXED SWELL WITH COMBINED SEAS OF 8-10 FT COVERS THE REMAINDER
OF THE WATERS N OF 10N W OF 115W. THIS SWELL WILL DECAY TO LESS
THAN 8 FT DURING THE NEXT 24-48 HOURS WITH THE ONLY REMAINING
AREA OF SEAS 8-9 FT BECOMING CONFINED TO THE W CENTRAL WATERS N
OF THE ITCZ BY THU MORNING.

GULF OF PAPAGAYO...STRONG HIGH PRESSURE WILL BUILD EASTWARD IN
THE WAKE OF A COLD FRONT MOVING ACROSS THE GULF OF MEXICO INTO
THE WESTERN CARIBBEAN. EXPECT FRESH TO STRONG NE WINDS
DOWNSTREAM FROM THE GULF OF PAPAGAYO EARLY THU MORNING THROUGH
THU EVENING WITH SEAS BUILDING TO 10-11 FT. SEAS GREATER THAT 8
FT GENERATING BY THE GAP WIND EVENTS ACROSS THE GULFS OF
TEHUANTEPEC AND PAPAGAYO ARE EXPECTED TO MERGE BY LATE THU
COVERING ROUGHLY THE WATERS FROM 05N TO 14N BETWEEN 87W AND 108W.

$$
GR


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