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AXPZ20 KNHC 242121
TWDEP

TROPICAL WEATHER DISCUSSION
NWS NATIONAL HURRICANE CENTER MIAMI FL
2205 UTC FRI APR 24 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 1800 UTC SURFACE ANALYSIS AND SATELLITE IMAGERY THROUGH 2100 UTC.


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

THE MONSOON TROUGH AXIS EXTENDS FROM 09N82W TO 06N96W. THE ITCZ AXIS EXTENDS FROM 06N97W TO 07N107W THEN RESUMES FROM 06N125W TO 04N140W. SCATTERED MODERATE AND ISOLATED STRONG CONVECTION IS FROM 02N TO 07N BETWEEN 78W AND 90W...AND FROM 02N TO 07N W OF 132W. SCATTERED MODERATE CONVECTION IS WITHIN 60 NM EITHER SIDE OF THE AXIS BETWEEN 125W AND 130W.


...DISCUSSION...

A MIDDLE TO UPPER LEVEL TROUGH DOMINATES THE NW AND N CENTRAL WATERS EXTENDING FROM 32N110W THROUGH 20N120W TO 11N130W. WATER VAPOR SATELLITE IMAGERY SHOWS MAINLY DRY AND STABLE AIR W OF THE TROUGH AXIS. A LARGE AND EXPANSIVE UPPER LEVEL ANTICYCLONE IS ANCHORED OVER THE NW CARIBBEAN SEA WITH ANTICYCLONIC FLOW ALOFT AROUND IT ACROSS THE NE TROPICAL PACIFIC WATERS TO THE E OF THE UPPER TROUGH. UPPER LEVEL SW FLOW IS TRANSPORTING DEEP TROPICAL MOISTURE FROM THE ITCZ TO THE NE ACROSS N CENTRAL MEXICO AHEAD OF THE UPPER TROUGH AND AROUND THE UPPER ANTICYCLONE.

AT THE SURFACE...A 1029 MB HIGH CENTER IS LOCATED NEAR 32N142W WITH A RIDGE AXIS EXTENDING TO THE SE THROUGH 28N127W TO 18N104W. A PAIR OF TROUGHS ARE EMBEDDED IN THE ITCZ...THE EASTERN ONE EXTENDING FROM 15N104W TO 08N109W...AND THE WESTERN ONE FROM 14N120W TO 05N132W. SCATTERED MODERATE CONVECTION IS FROM 05N TO 10N BETWEEN 118W AND 123W. THE PRESSURE GRADIENT ACROSS THE W CENTRAL WATERS IS TIGHT ENOUGH BETWEEN THESE FEATURES TO SUPPORT FRESH TO STRONG NE-E TRADE WINDS WITH AN AREA OF SURROUNDING COMBINED SEAS OF 8-11 FT. THESE CONDITIONS WILL PERSIST ACROSS THE SAME GENERAL AREA THROUGH THE NEXT 48 HOURS OR SO.

FRESH TO STRONG NORTHERLY WINDS ARE OCCURRING JUST N OF THE AREA AROUND AND OFFSHORE OF POINT CONCEPTION CALIFORNIA. THESE WINDS ARE HELPING TO MAINTAIN NORTHERLY SWELL WHICH IS SEEPING INTO THE N CENTRAL DISCUSSION WATERS. THIS SWELL WILL DECAY TO LESS THAN 8 FT BY SAT MORNING. A NEW ROUND OF FRESH TO STRONG NW- N WINDS WILL DEVELOP OFFSHORE OF SOUTHERN CALIFORNIA AND ALSO OFFSHORE OF BAJA CALIFORNIA NORTE SAT EVENING WHICH WILL THEN PERSIST THROUGH SUN WITH ASSOCIATED SEAS BUILDING BACK TO 8-11 FT BY SUN AFTERNOON.

GULF OF CALIFORNIA...TROUGHING EXTENDS FROM FAR NW CALIFORNIA NEAR 32N115W TO 29N114W. SOUTHERLY FLOW IN THE GULF OF CALIFORNIA HAVE DIMINISHED SLIGHTLY TO 15-20 KT WHICH WILL PERSIST THROUGH EARLY SAT. THE PRESSURE GRADIENT ACROSS THE REGION WILL TIGHTEN SAT AFTERNOON WITH A POCKET OF 20-30 KT SOUTHWESTERLY WINDS FROM 29.5N TO 30.5N BY 00 UTC SUN INTO SAT EVENING.

GULF OF PAPAGAYO...GAP WINDS ARE FORECAST TO PULSE TO FRESH TO STRONG LEVELS AGAIN LATE TONIGHT INTO EARLY SAT DURING PEAK NOCTURNAL DRAINAGE FLOW.

GULF OF PANAMA...NORTHERLY WINDS WILL BRIEFLY INCREASE TO FRESH TO STRONG JUST SW OF THE IMMEDIATE GULF LATE TONIGHT THROUGH THE MORNING SAT AS THE LOCAL PRESSURE GRADIENT BRIEFLY TIGHTENS.

$$ LEWITSKY

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