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Eastern North Pacific Tropical Weather Discussion



000
AXPZ20 KNHC 120317
TWDEP 

TROPICAL WEATHER DISCUSSION                                    
NWS NATIONAL HURRICANE CENTER MIAMI FL                        
0405 UTC FRI FEB 12 2015 

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 0000 UTC SURFACE ANALYSIS AND SATELLITE IMAGERY THROUGH
0315 UTC.               

...SPECIAL FEATURES... 

GULF OF TEHUANTEPEC GALE WARNING...GALE FORCE NORTHERLY WINDS...
WITH SEAS TO 17 FT...ARE EXPECTED TO PERSIST THROUGH SUN
MORNING. THE N WINDS WILL GRADUALLY DIMINISH TO 20 KT OR LESS
LATE MON MORNING. THE RESULTANT SWELL CONTINUES TO PROPAGATE SE
THROUGH SW...MERGING WITH ENE SWELL GENERATED FROM THE GULF OF
PAPAGAYO GALE EVENT...MERGING WITH CROSS-EQUATORIAL SW SWELL AND
ALSO MERGING WITH LONG PERIOD NW SWELL. SEAS 12 FT OR GREATER
ARE EXPECTED TO REACH ALONG 05N BETWEEN 90-101W TONIGHT AND
REACH ALONG 09N BETWEEN 98-102W ON SAT NIGHT...WITH SEAS 8 FT OR
GREATER REACHING THE EQUATOR BETWEEN 93-110W. SEE LATEST NWS
HIGH SEAS FORECAST UNDER AWIPS/ WMO HEADERS MIAHSFEP2/FZPN03
KNHC FOR MORE DETAILS.

GULF OF PAPAGAYO GALE WARNING...MINIMAL GALE CONDITIONS ARE
EXPECTED PERSIST THROUGH EARLY FRI MORNING. THE NARROW BAND OF GALE
CONDITIONS ARE SURROUNDED BY A LARGE AREA OF STRONG TO NEAR FLOW
EXTENDING AS FAR SW AS 07N96W...RESULTING IN SEAS BUILDING TO
ABOUT 14 FT NEAR 09N88W TONIGHT INTO EARLY FRI. PATCHES OF
STRONG NE FLOW WILL DEVELOP TONIGHT ACROSS THE WATERS N OF 12N
BETWEEN 87W AND 91W...INCLUDING THE GULF OF FONSECA...WITH SEAS
BUILDING TO A MAX OF 9 FT DUE TO THE LIMITED FETCH. EXPECT THE
NE FLOW TO DIMINISH TO 15-20 KT ON SUN AND MON AFTERNOONS THEN
INCREASE TO 20-25 KT AGAIN EACH NIGHT. SEE LATEST NWS HIGH SEAS
FORECAST UNDER AWIPS/WMO HEADERS MIAHSFEP2/FZPN03 KNHC FOR MORE
DETAILS.

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

SCATTEROMETER WINDS INDICATE THAT AN ITCZ FORMS NEAR 05N87W AND
EXTENDS W TO 02N101W...THEN TURNS NW TO 06N112W WITH AN EMBEDDED
TROUGH EXTENDING FROM 05N115W TO 11N115W. THE ITCZ RESUMES W OF
THE TROUGH AT 07N120W AND CONTINUES SW TO BEYOND 03N140W.
ISOLATED MODERATE TO STRONG CONVECTION IS OBSERVED WITHIN 300 NM
OF TROUGH. SCATTERED MODERATE ISOLATED STRONG CONVECTION IS
NOTED N OF THE ITCZ WITHIN 120 NM EITHER SIDE OF A LINE FROM
05N87W TO 05N109W AND WITHIN 30 NM OF W SEGMENT OF THE ITCZ
BETWEEN 120W AND 140W. 

...DISCUSSION...

ELSEWHERE N OF 15N E OF 120W...A BROAD AND WEAK SURFACE RIDGE
EXTENDS SE FROM 27N120W TO 16N100W. THE GRADIENT WILL SUPPORT
LIGHT N-NE FLOW ACROSS THE OPEN PACIFIC WATERS BETWEEN 106-120W
THROUGH EARLY SUN...THEN THE N WINDS WILL INCREASE TO MODERATE
AS THE GRADIENT TIGHTENS AROUND A RIDGE FROM 25N120W TO 17N106W.
COMBINED SEAS ARE CURRENTLY IN THE 3-6 FT RANGE PRIMARILY DUE TO
LONG PERIOD SW CROSS-EQUATORIAL SWELL AND LONG PERIOD NW SWELL.
LARGE NW SWELL...RESULTING IN COMBINED SEAS OF 7-10 FT...WILL
ARRIVE ACROSS THE WATERS N OF 28N ALONG 120W LATE TONIGHT...
REACH THE PACIFIC COAST OF THE NORTHERN BAJA PENINSULA ON FRI
AFTERNOON...REACH THE SOUTHERN PORTION OF BAJA LATE FRI NIGHT
AND PERSIST THROUGH LATE SUN...THEN SUBSIDE FROM THE N ON MON.
LIGHT AND VARIABLE WINDS ARE OBSERVED BETWEEN 97-106W WITH THE
PREVIOUSLY DESCRIBED GALE EVENT OCCURRING ACROSS THE WATERS TO
THE E OF 97W. MODERATE NW WINDS ARE EXPECTED ACROSS THE GULF OF
CALIFORNIA THROUGH LATE SUN INCREASING TO FRESH ON SUN NIGHT
ACROSS THE CENTRAL GULF WATERS.   

S OF 15N E OF 110W...EXCEPT AS PREVIOUSLY DESCRIBED FOR THE
GULFS OF TEHUANTEPEC...FONSECA AND PAPAGAYO...MODERATE TO FRESH
N WINDS ARE EXPECTED TODAY ACROSS THE TROPICAL WATERS N OF ABOUT
04N AND W OF ABOUT 87W. PULSES OF FRESH TO STRONG NORTHERLY
WINDS WILL SPREAD S FROM THE GULF OF PANAMA TO ALONG ABOUT 04N
EACH NIGHT THROUGH THROUGH THE UPCOMING WEEKEND WITH SEAS
BUILDING TO ABOUT 10 FT NEAR 06N81W. 

ELSEWHERE FROM 00-32N E OF 140W...A SURFACE HIGH MEANDERING NEAR
32N126W CONTINUES TO BLOCK THE EASTWARD ADVANCE OF WEAK COLD
FRONTS. A COLD FRONT CURRENTLY EXTENDS FROM 32N133W TO 27N140W.
THIS COLD FRONT WILL STALL FROM 32N133W TO 25N140W EARLY FRI AND
QUICKLY DISSIPATE. ALTHOUGH EXPECTING ONLY A 10-15 KT SW-W-NW-N
WIND SHIFT WITH THE FRONT ACROSS THE WATERS S OF 32N...THERE IS
SIGNIFICANT LONG PERIOD NW SWELL BEHIND THE FRONT DRIVING
COMBINED SEAS UP TO A HIGH AS 18 FT NEAR 31N140W. EXPECT SEAS OF
12 FT OR GREATER TO PROPAGATE E TO A LINE FROM 32N120W TO
05N140W ON SAT BEFORE BEGINNING TO SUBSIDE. THE PRESSURE
GRADIENT WILL TIGHTEN ON SAT NIGHT INTO SUN WITH FRESH TO
LOCALLY STRONG NE-E WINDS ACROSS THE WATERS N OF 10N THROUGH SUN
EVENING.

$$
NELSON