Tropical Weather Discussion
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000
AXPZ20 KNHC 210954 RRA
TWDEP

TROPICAL WEATHER DISCUSSION
NWS NATIONAL HURRICANE CENTER MIAMI FL
1005 UTC SUN DEC 21 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.

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

THE MONSOON TROUGH AXIS EXTENDS FROM 06N78W TO 06N97W. THE ITCZ
AXIS EXTENDS FROM 06N97W TO LOW PRES NEAR 08N107W TO 06N125W TO
06N140W. SCATTERED MODERATE CONVECTION IS WITHIN 90 NM N OF THE
AXIS E OF 80W...WITHIN 120 NM S OF THE AXIS BETWEEN 109W AND
113W...AND ALSO WITHIN 120 NM N OF THE AXIS BETWEEN 130W AND
134W.

...DISCUSSION...

LONG PERIOD NW SWELL CONTINUES TO PROPAGATE SE-E ACROSS THE
ENTIRE OPEN WATERS WATERS N OF THE ITCZ W OF ABOUT 112W
RESULTING IN COMBINED SEAS OF 8-14 FT...WITH THE HIGHEST SEAS
NEAR 28N120W. THIS LONG PERIOD NW SWELL HAS NOW ARRIVED ALONG
THE PACIFIC COAST OF BAJA CALIFORNIA NORTE WHERE WINDS ARE ALSO
NW-N AT 20-25 KT AS SAMPLED BY A RECENT ASCAT SCATTEROMETER
PASS. EXPECT 7-10 FT SEAS SPREADING SOUTHWARD ALONG BAJA
CALIFORNIA SUR THROUGH THE REST OF TODAY. THE SWELLS WILL THEN
SUBSIDE WITH 5-8 FT CONDITIONS EXPECTED ALONG THE ENTIRE PACIFIC
COAST OF THE BAJA PENINSULA ON MON AND MON NIGHT...AND 4-7 FT
SEAS EXPECTED ON TUE ACROSS THE COASTAL WATERS S OF 28N.

MODEL GUIDANCE IS SUGGESTING THAT NORTHERLY FLOW WILL INCREASE
TO 20-25 KT N OF 27N BETWEEN 120W AND 123W BY 24 HOURS WHERE
SEAS WILL ALSO BE 11-13 FT...DIMINISHING TUE. NE WINDS AT 20-25
KT WILL BLEED THROUGH BAJA CALIFORNIA NORTE PASSES STARTING
TUE...SPREADING SW TO NEAR 27N116W BY EARLY WED BEFORE
DIMINISHING TO 15 KT LATE WED.

A 1029 MB SURFACE HIGH IS ANALYZED AT 32N132W WITH A RIDGE
EXTENDING SE TO NEAR 20N112W. NE 15-20 KT TRADES ARE OBSERVED
ACROSS THE TROPICS BETWEEN THE ITCZ AND THE RIDGING WITH AN AREA
OF EMBEDDED 20-25 KT NE WINDS AND 9-14 FT SEAS ACROSS THE W
CENTRAL WATERS FROM 07N TO 22N W OF 120W. THE PRESSURE GRADIENT
WILL GRADUALLY RELAX THROUGH MON NIGHT WITH THE EFFECTED AREA OF
20-25 KT CONDITIONS SHRINKING ACROSS THE WATERS FROM 08N TO 14N
W OF 130W...DIMINISHING TO 20 KT OR LESS ACROSS THE DISCUSSION
WATERS ON TUE WITH MORE TRANQUIL CONDITIONS PERSISTING THROUGH
FRI. THE COMBINED SEAS WILL CONTINUE TO SUBSIDE TO THE 6-9 FT
RANGE ACROSS THE PACIFIC WATERS W OF 115W BY THU.

GULF OF CALIFORNIA...NW-N 15-20 KT WINDS ARE EXPECTED THROUGH
MON NIGHT. THE PRESSURE GRADIENT WILL TIGHTEN ACROSS THE REGION
EARLY TUE WITH THE NW FLOW INCREASING TO 20-25 KT ACROSS THE
NORTHERN GULF WATERS TUE MORNING...AND 20-30 KT CONDITIONS
SPREADING S ACROSS THE ENTIRE GULF OF CALIFORNIA BY TUE EVENING.
SEAS WILL BUILD TO 10-11 FT IN LONG FETCH WATERS NEAR 28N BY TUE
EVENING. THE GRADIENT WILL RELAX ON WED WITH 15-20 KT FLOW ON
WED NIGHT AND ONLY 10-15 KT NW FLOW ON THU WITH WINDS BECOMING
SOUTHERLY AT 5-10 KT THU NIGHT THROUGH EARLY FRI.

GULF OF TEHUANTEPEC...A RAPIDSCAT SCATTEROMETER PASS A FEW HOURS
AGO INDICATED FRESH NORTHERLY WINDS IN THE GULF PRIOR TO PEAK
NOCTURNAL DRAINAGE FLOW...WHILE THE LATEST RAP AND GFS MODEL
GUIDANCE SHOWS WINDS INCREASING TO STRONG LEVELS THROUGH THE
EARLY MORNING HOURS. EXPECT ONLY 10-15 KT DRAINAGE FLOW TONIGHT
WITH LIGHT AND VARIABLE WINDS MON NIGHT THROUGH TUE. A STRONG
COLD FRONT WILL BLAST BY TO THE N THROUGH THE SW GULF OF MEXICO
WED WITH STRONG HIGH PRESSURE RIDGING FILLING IN ACROSS SE
MEXICO IN ITS WAKE. NORTHERLY WINDS WILL SURGE THROUGH THE
CHIVELA PASS INCREASING TO GALE FORCE WED AFTERNOON...FURTHER
INCREASING TO NEAR STORM STRENGTH LATE WED NIGHT. EXPECT THE
GALE EVENT TO END BY FRI MORNING.

GULF OF PAPAGAYO...NE 15-20 KT NOCTURNAL PULSES ARE EXPECTED
THROUGH EARLY MON...THEN ONLY 10-15 KT DRAINAGE FLOW MON NIGHT
THROUGH THU MORNING. MODEL GUIDANCE INDICATES A SIGNIFICANT 20-
30 KT GAP WIND EVENT ON THU NIGHT THROUGH FRI AFTERNOON
EXTENDING AS FAR SW AS 08N93W.

$$
LEWITSKY



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