000
AXPZ20 KNHC 180915
TWDEP 

TROPICAL WEATHER DISCUSSION
NWS NATIONAL HURRICANE CENTER MIAMI FL
1005 UTC FRI MAR 18 2016

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 NORTHERN ITCZ AXIS EXTENDS FROM 07N92W TO 04N110W TO 04N125W.
THE SOUTHERN ITCZ AXIS EXTENDS FROM 01S105W TO 02S120W. ISOLATED
MODERATE CONVECTION IS WITHIN 90 NM N OF THE NORTHERN AXIS
BETWEEN 111W AND 120W...AND S OF THE EQUATOR W OF 110W.

...DISCUSSION...                                               
A MIDDLE TO UPPER LEVEL SHORTWAVE TROUGH IS NOTED ON WATER VAPOR
IMAGERY NORTH OF THE DISCUSSION AREA NEAR 42N134W WITH AN AXIS
THAT EXTENDS SW TO NEAR 30N148W TO OVER THE HAWAIIAN ISLANDS
NEAR 21N159W. THE TROUGH SUPPORTS A WEAKENING COLD FRONT
EXTENDING FROM 31N135W TO 26N140W WITH RECENT ASCAT PASSES
INDICATING GENTLE TO MODERATE SOUTHERLIES WITHIN 90 NM EAST OF
THE BOUNDARY...AND MODERATE N-NW WINDS WEST OF THE FRONT. SEAS
WEST OF THE FRONT CONTINUE TO RANGE FROM 8 FT ALONG THE FRONT TO
12 FT AT 30N140W IN NW SWELL. AS THE FRONT WEAKENS AND BECOMES
STATIONARY DURING THE NEXT 24 HOURS...THE NW SWELL TRAIN WILL
CONTINUE PROPAGATING SOUTHEAST AND SPREAD ACROSS THE
NORTHWESTERN WATERS THROUGH SATURDAY AND EVENTUALLY IMPACT THE
WEST-CENTRAL WATERS SATURDAY NIGHT INTO SUNDAY AS SEAS OVERALL
BEGIN TO GRADUALLY SUBSIDE. BY SUNDAY AS THIS OCCURS...THE NEXT
WAVE OF ENERGY IN THE FORM OF A REINFORCING FRONT WILL EXTEND
FROM 30N134W TO 25N140W AND AGAIN INTRODUCE ANOTHER PULSE OF NW
SWELL WITH SEAS ONCE AGAIN BUILDING TO 12 FT AT THE NW CORNER OF
THE DISCUSSION AREA BY SUN MORNING.

OTHERWISE...ASIDE FROM THE ITCZ REGION...A 1021 MB HIGH IS
CENTERED NEAR 27N131W WITH AN AXIS EXTENDING SE TO NEAR 13N110W.
THE OVERALL PRESSURE GRADIENT BETWEEN THE RIDGE AND LOWER
PRESSURE TO THE SOUTH WITHIN THE ITCZ REGION IS SUPPORTING
MODERATE TO OCCASIONAL FRESH N TO NE TRADES WITH SEAS RANGING 5-
7 FT.

BEYOND 48 HOURS...A RELATIVELY STRONG COLD FRONT IS FORECAST TO
MOVE SE ACROSS THE GULF OF MEXICO AND REACH THE CHIVELA PASS ON
SUN. THE BUILDING HIGH PRES BEHIND THE FRONT WILL INDUCE A GULF
OF TEHUANTEPEC GAP WIND EVENT. CURRENTLY...GALE CONDITIONS ARE
FORECAST FROM SUN NIGHT THROUGH TUE MORNING...WITH PEAK
SUSTAINED WINDS FORECAST TO REACH 40 KT WITH POSSIBLE HIGHER
GUSTS DURING THIS EVENT. LATEST WAVEWATCH GUIDANCE INDICATES
THAT WAVE HEIGHTS MAY REACH A RANGE OF ABOUT 15-19 FT SUN NIGHT
INTO MON AFTERNOON IN THE GULF REGION AND DOWNWIND TO THE S AND
SW.

IN ADDITION...A GULF OF PAPAGAYO GAP WIND EVENT WITH 20-25 KT NE
WINDS IS SUGGESTED BY MODEL GUIDANCE TO BRIEFLY TAKE PLACE MON
MORNING AND LIKELY PULSE EACH MORNING THROUGH WED.

$$
HUFFMAN