Tropical Weather Discussion
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000
AXPZ20 KNHC 250928
TWDEP

TROPICAL WEATHER DISCUSSION
NWS NATIONAL HURRICANE CENTER MIAMI FL
1005 UTC THU DEC 25 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 FEATURES...
GULF OF TEHUANTEPEC GALE WARNING...A COLD FRONT HAS PASSED TO
THE NE OF THE ISTHMUS OF TEHUANTEPEC REGION WITH COLD DENSE AIR
FUNNELING THROUGH THE CHIVELA PASS GENERATING GALE FORCE WINDS
IN THE GULF OF TEHUANTEPEC. A PAIR OF RECENT SCATTEROMETER
SATELLITE PASSES VERIFY GALES ARE ONGOING IN THE GULF OF
TEHUANTEPEC. SEAS ARE FORECAST TO BUILD UP TO 15 FT THROUGH THIS
MORNING. HIGH PRES IN THE GULF OF MEXICO WILL QUICKLY SHIFT EAST
FROM THIS MORNING LATE INTO THE AFTERNOON HOURS WHILE WEAKENING
ACROSS THE WESTERN GULF OF MEXICO. THIS WILL ALLOW WINDS IN THE
GULF OF TEHUANTEPEC TO QUICKLY DIMINISH BELOW GALE FORCE THIS
AFTERNOON...AND BELOW 20 KT BY FRI. NE SWELL IN EXCESS OF 8 FT
WILL PROPAGATE SOUTHWEST AWAY FROM THE GULF REGION AFTER THE
ONSET OF THE GALE EVENT...AND REACH FROM 07N TO 14N BETWEEN 98W
AND 105W FRI MORNING.

...INTERTROPICAL CONVERGENCE ZONE/MONSOON TROUGH...
THE MONSOON TROUGH EXTENDS FROM 07N78W TO 06N90W TO
07N95W...WHERE IT TRANSITIONS TO AN ITCZ. THE ITCZ REACHES FROM
07N95W TO 07N100W TO BEYOND 07N140W. SCATTERED MODERATE
CONVECTION IS NOTED WITHIN 60 NM EITHER SIDE OF ITCZ AXIS
BETWEEN 105W AND 115W.

...DISCUSSION...

A DEEP LAYER RIDGE REMAINS ANCHORED ALONG ROUGHLY 140W...WITH AN
ASSOCIATED 1035 MB CENTERED N OF THE AREA NEAR 42N140W. THE
SURFACE HIGH PRES IS BEING DISPLACED FARTHER N OF THE AREA BY
DEVELOPING LOW PRES NE OF HAWAII. AS A RESULT...TRADE WINDS OVER
THE TROPICAL E PACIFIC W OF 120W REMAIN LIMITED TO 15 TO 20 KT
OR LESS. MEANWHILE THE TIGHTENING GRADIENT BETWEEN THE
DEVELOPING LOW PRES NE OF HAWAII AND THE RIDGE TO THE NORTH IS
PROMOTING FRESH TO STRONG E TO SE WINDS OVER THE FAR NW PORTION
OF THE DISCUSSION AREA...N OF 24N AND W OF 130W. THIS PATTERN
WILL PERSIST THROUGH THE NEXT SEVERAL DAYS...WITH SOME POTENTIAL
FOR WINDS TO NEAR GALE FORCE BY LATE SAT.

A VIGOROUS MID LEVEL SHORT WAVE TROUGH IS MOVING ACROSS THE
WESTERN UNITED STATES ON THE WEST SIDE OF THE RIDGE...SUPPORTING
THE APPROACH OF A COLD FRONT ACROSS SOUTHERN CALIFORNIA AND
ADJACENT PACIFIC WATERS. THIS FRONT WILL PUSH INTO THE NORTHERN
GULF OF CALIFORNIA AND BAJA CALIFORNIA NORTE LATE
TODAY...THROUGH THE MIDDLE GULF OF CALIFORNIA AND INTO BAJA
CALIFORNIA SUR BY LATE FRI BEFORE BECOMING DIFFUSE SAT. STRONG
NW FLOW IS FOLLOWING THE FRONT ALONG THE CALIFORNIA COAST. N TO
NE WINDS OF 20 TO 25 KT WILL PENETRATE SOUTH TO NEAR 28N BY LATE
TODAY. ASSOCIATED SHORT PERIOD SWELL WITH HEIGHTS OF 12 TO 14 FT
WILL FOLLOW IN THE WATERS N OF 28N BETWEEN 116W AND 125W BEFORE
DECAYING TO 8 FT BY LATE FRI.

RECENT ALTIMETER SATELLITE PASSES INDICATE EVIDENCE OF LONG
PERIOD NW SWELL WITH HEIGHTS OF 8 TO 10 FT FROM AN EARLIER EVENT
LINGERING ACROSS THE WATERS W OF A LINE FROM 30N115W TO 20N112W
TO 00N130W. THIS WILL DECAY BELOW 8 FT EXCEPT WHERE IT IS MIXED
WITH WAVES GENERATED FROM TRADE WINDS AND WHERE REINFORCED FROM
NORTHERLY SWELL N OF 25N.

A CUT OFF UPPER LOW PREVIOUSLY NEAR 16N105W IS NOW LIFTING NE
AHEAD OF A SHARP UPPER TROUGH REACHING FROM N CENTRAL MEXICO TO
10N120W. ASSOCIATED DIVERGENCE OF THE UPPER LOW IS SUPPORTING A
FEW SHOWERS AND THUNDERSTORMS ALONG THE COAST OF MEXICO FROM
ACAPULCO TO MANZANILLO.

GULF OF PAPAGAYO...BUILDING HIGH PRES INTO THE NW CARIBBEAN WILL
PROMOTE FRESH TO STRONG GAP WINDS INTO THE GULF OF PAPAGAYO
STARTING LATE TODAY. AIDED BY LOCAL OVERNIGHT DRAINAGE
EFFECTS...GAP WINDS WILL REACH NEAR GALE FORCE OVERNIGHT. THIS
WILL GENERATE A PLUME OF 8 TO 11 FT SEAS OUT TO 350 NM INTO THE
EASTERN PACIFIC DOWNSTREAM OF THE GULF OF PAPAGAYO BY FRI...WITH
SHORT PERIOD 8 TO 9 FT SWELL REACHING AS FAR AS 100W BY LATE
SAT. A WEAKER SECONDARY PULSE IS EXPECT FRI NIGHT/EARLY SAT
MORNING.

$$
CHRISTENSEN


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