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Eastern Pacific Tropical Weather Discussion (Text)



000
AXPZ20 KNHC 070334
TWDEP 

TROPICAL WEATHER DISCUSSION                                     
NWS NATIONAL HURRICANE CENTER MIAMI FL                         
0405 UTC SAT MAR 07 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 
0300 UTC. 

...SPECIAL FEATURE...

A STORM WARNING REMAINS IN EFFECT FOR THE GULF OF TEHUANTEPEC.  
PERSISTENT STRONG HIGH PRESSURE EXTENDING SOUTHWARD ALONG THE 
MEXICO COASTAL PLAINS TO SOUTH CENTRAL MEXICO CONTINUES TO 
MAINTAIN A TIGHT PRESSURE GRADIENT INTO THE GULF OF TEHUANTEPEC. 
THIS IS SUPPORTING MINIMAL STORM FORCE WINDS FLUCTUATING 40-50 
KT THROUGH THE GULF OF TEHUANTEPEC...WITH GALE FORCE WINDS 
EXTENDING DOWNWIND SOME 220-240 NM. IZTEPEC IN THE NORTHERN END 
OF THIS GULF HAS REPORTED GUSTY WINDS OF AROUND 40 KT FOR 
SEVERAL HOURS. SEAS WILL BUILD TO 22-23 FT WITH THE STRONGEST 
WINDS. THE PRESSURE GRADIENT SHOULD BEGIN TO RELAX BY SAT 
MORNING WITH THE NORTHERLY FLOW DIMINISHING TO A STRONG GALE 
AROUND 1800 UTC...THEN CONTINUE TO WEAKEN THROUGHOUT THE DAY SAT 
INTO SAT NIGHT WITH ONLY MINIMAL GALE CONDITIONS EXPECTED EARLY 
SUN MORNING...AND BELOW GALE FORCE WINDS BY SUN AFTERNOON. THIS 
WILL BE THE THIRD STORM EVENT TO OCCUR ACROSS THE GULF OF 
TEHUANTEPEC DURING THIS COLD SEASON. THE NEXT TEHUANTEPEC EVENT 
IS EXPECTED TO BEGIN WITH 20-25 KT NORTHERLY WINDS ON TUE 
NIGHT...GRADUALLY INCREASING TO A MINIMAL GALE ON WED EVENING 
THROUGH SUNRISE ON THU.      

A GALE WARNING IS IN EFFECT FOR THE GULF OF PAPAGAYO. THIS SAME 
STRONG PRESSURE GRADIENT IS COMBINING WITH STRONG TRADE WINDS 
ACROSS THE CENTRAL AND SW CARIBBEAN TO SUPPORT STRONG GAP WINDS 
ACROSS THE GULF OF PAPAGAYO. WINDS ARE EXPECTED TO PULSE TO 
MINIMAL GALE FORCE WITH THE ASSISTANCE OF THE NOCTURNAL DRAINAGE 
FLOW TONIGHT THROUGH THE EARLY MORNING HOURS SAT...AND AGAIN SAT 
NIGHT INTO EARLY SUN MORNING...WITH WINDS OF 20-30 KT EXTENDING 
DOWNWIND TO NEAR 93W. EXPECT BUILDING SEAS TO AROUND 12 FT WITH 
THE STRONGEST WINDS.

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

THE ITCZ EXTENDS FROM 03N87W TO 02N100W TO 03N107W THEN RESUMES 
AT 03N110W TO 01N125W TO BEYOND 02N140W. A SECOND ITCZ AXIS IS 
NOTED SOUTH OF THE EQUATOR AND EXTENDS FROM 07S90W TO 06S120W. 
DURING MARCH AND APRIL...IT IS USUAL TO OBSERVE A DOUBLE ITCZ 
AXES. NO SIGNIFICANT CONVECTION WITH THESE FEATURES.

...DISCUSSION... 

A SURFACE RIDGE EXTENDS SE FROM A 1026 MB HIGH PRESSURE LOCATED 
N OF AREA NEAR 41N127W TO 20N110W. THE TRADE WINDS SW OF THE 
RIDGE ARE AT 15-20 KT WITH COMBINED SEAS OF 7-9 FT IN MIXING NE 
TRADES...ALONG WITH LONG PERIOD SW AND NW SWELL. THE GRADIENT IS 
EXPECTED TO INCREASE SW OF THE RIDGE OVER THE WEEKEND...WITH 
EMBEDDED PATCHES OF 20-25 KT WINDS AND SEAS BUILDING TO 10 FT. 
REINFORCING NE SWELL...ORIGINATING FROM A STORM EVENT IN THE 
GULF OF TEHUANTEPEC AND A GALE EVENT IN THE GULF OF PAPAGAYO... 
WILL PROPAGATE WSW INTO THE TROPICAL WATERS TO THE S OF 13N... 
AND SPREAD W ACROSS THE WATERS BETWEEN 110-120W WELL INTO NEXT 
WEEK MIXING WITH THE NE TRADE WIND SWELL. 

A COLD FRONT IS FORECAST TO APPROACH THE FAR NW CORNER OF THE 
AREA EARLY SAT MORNING. AT THIS TIME...SOUTHERLY WINDS AHEAD OF 
THE FRONT WILL INCREASE TO 20-30 KT WITH BUILDING SEAS TO AROUND 
12 FT DUE TO THE PRES GRADIENT BETWEEN THE ABOVE MENTIONED RIDGE 
AND THE FRONT. IT WILL BE NEAR 30N140W BY SAT AFTERNOON...THEN 
WILL BECOME NEARLY STATIONARY OVER THE NW CORNER OF THE FORECAST 
AREA ON SUN BEFORE DISSIPATING. ADDITIONAL PULSES OF NW SWELL 
WILL FOLLOW THE FRONT.

GAP WINDS...                                                 

THE ENHANCED NE WINDS ACROSS THE GULF OF PAPAGAYO WILL ALSO 
SPREAD N ALONG THE COAST OF NICARAGUA TO THE GULF OF FONSECA 
MAINLY DURING THE OVERNIGHT AND EARLY MORNING HOURS LIKELY 
THROUGH MON MORNING. 

GULF PANAMA...NORTHERLY WINDS ARE EXPECTED TO INCREASE TO 20-25 
KT THIS EVENING...AND SPREAD AS FAR S AS 05N81W TONIGHT INTO 
EARLY SAT MORNING...AND AS FAR SW AS 04N82W ON EARLY SUN MORNING 
WITH MAX SEAS OF 9 FT EACH NIGHT DOWNSTREAM OF THE GULF PANAMA. 

$$ 
GR


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Page last modified: Saturday, 07-Mar-2015 03:34:37 UTC