Tropical Weather Discussion
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000
AXPZ20 KNHC 200926
TWDEP

TROPICAL WEATHER DISCUSSION
NWS NATIONAL HURRICANE CENTER MIAMI FL
1005 UTC SAT DEC 20 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 05N77W TO 10N86W TO 09N89W.
THE ITCZ AXIS EXTENDS FROM 09N89W TO 08N97W THEN RESUMES FROM
07N103W TO 05N130W TO 05N140W. SCATTERED MODERATE AND ISOLATED
STRONG CONVECTION IS WITHIN 75 NM EITHER SIDE OF THE AXIS
BETWEEN 79W AND 82W. SCATTERED MODERATE CONVECTION IS WITHIN 75
NM N OF THE AXIS BETWEEN 116W AND 119W.

...DISCUSSION...

HIGH PRESSURE AT 1025 MB NEAR 27N125W EXTENDS A RIDGE TO THE SE
NEAR 15N110W. THE PRESSURE GRADIENT BETWEEN THE RIDGING AND
LOWER PRESSURES ALONG THE ITCZ IS TIGHT ENOUGH TO SUPPORT FRESH
TO STRONG TRADES ACROSS THE W CENTRAL WATERS WHICH WILL PERSIST
THROUGH 48 HOURS...EXPANDING SLIGHTLY IN COVERAGE AS THE
GRADIENT CONTINUES TO TIGHTEN.

MEANWHILE LARGE NW SWELL UP TO 18 FT IS MOVING IN BEHIND THE
REMNANTS OF A COLD FRONT WHICH ARE SCRAPING ACROSS THE WATERS
FROM JUST W OF THE CALIFORNIA CHANNEL ISLANDS INTO THE N CENTRAL
WATERS. A RECENT NEARBY ALTIMETER PASS SHOWING SEAS UP TO 15 FT
AND A FEW SHIP REPORTS UP TO 13 FT. AN OLD SET OF NW SWELL IS
MIXING WITH NE WIND WAVES GENERATED BY THE TRADES MENTIONED
ABOVE AND COMBINED SEAS OF 8 FT OR GREATER COVER THE MAJORITY
OF THE WATERS W OF 110W. MAXIMUM SEAS WILL SUBSIDE TO 13 FT BY
48 HOURS.

THIS LONG PERIOD NW SWELL WILL ARRIVE ALONG THE PACIFIC COAST OF
THE BAJA PENINSULA IN THE FORM OF 8-13 FT SEAS THIS AFTERNOON
WITH 7-10 FT SEAS EXPECTED ALONG THE ENTIRE PACIFIC COAST OF THE
BAJA PENINSULA ON SUN. THE SWELLS WILL SUBSIDE WITH 6-8 FT
CONDITIONS EXPECTED ALONG THE ENTIRE PACIFIC COAST OF THE BAJA
PENINSULA ON MON AND MON NIGHT...THEN SUBSIDING TO 4-6 FT ON TUE
ACROSS THE COASTAL WATERS S OF 28N.

SATELLITE IMAGERY AND SCATTEROMETER DATA SHOW A WEAK 1011 MB LOW
PRESSURE AREA EMBEDDED IN THE ITCZ NEAR 08N100W MOVING W AROUND
10 KT. SCATTERED MODERATE AND ISOLATED STRONG CONVECTION IS
WITHIN 120 NM IN THE NW SEMICIRCLE OF THE LOW WHILE SEAS ARE 8-9
FT WITHIN 180 NM OF THE LOW CENTER. THE LOW IS FORECAST TO REACH
NEAR 08.5N110W AT 1011 MB BY 48 HOURS WHILE THE ASSOCIATED SEAS
MERGE WITH THE AREA OF NW SWELL MENTIONED ABOVE.

GULF OF CALIFORNIA...RECENT ASCAT AND RAPIDSCAT SCATTEROMETER
PASSES INDICATED 20-25 KT NW-N WINDS IN THE GULF FROM 23N TO 28N
W OF 108W...WITH 15-20 KT ELSEWHERE. WINDS WILL DIMINISH TO 15-
20 KT LATER TODAY...FURTHER DIMINISHING TO 10-15 KT MON. MODEL
GUIDANCE INDICATES WINDS INCREASING TO 20-30 KT N OF 26N W OF
110W TUE...PERSISTING FOR ABOUT 24 HOURS.

GULF OF TEHUANTEPEC...A MAXIMUM OF 10-15 KT NOCTURNAL DRAINAGE
FLOW IS OCCURRING TONIGHT INTO THE EARLY MORNING HOURS...
INCREASING TO 20-25 KT SAT NIGHT INTO EARLY SUN...THEN BACK TO
10-15 KT SUN NIGHT INTO EARLY MON. MODEL GUIDANCE CONTINUES TO
SUGGEST THE THE NEXT GALE EVENT WILL BEGIN AROUND SUNRISE ON
WED INCREASING TO NEAR STORM STRENGTH ON WED NIGHT.

GULF OF PAPAGAYO...NE 15-20 KT NOCTURNAL PULSES EXPECTED
THROUGH EARLY MON...THEN ONLY 10-15 KT DRAINAGE FLOW EARLY
TUE...THE BECOMING LIGHT AND VARIABLE WED.

$$
LEWITSKY


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