Home


000
AXPZ20 KNHC 301600
TWDEP

TROPICAL WEATHER DISCUSSION
NWS NATIONAL HURRICANE CENTER MIAMI FL
1605 UTC SAT MAY 30 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 1200 UTC SURFACE ANALYSIS AND SATELLITE IMAGERY THROUGH 1500 UTC.


...SPECIAL FEATURE...

HURRICANE ANDRES WAS CENTERED NEAR 14.5N 115.9W AT 30/1500 UTC MOVING NW OR 325 DEG AT 6 KT. ESTIMATED MINIMAL CENTRAL PRESSURE WAS 970 MB. MAXIMUM SUSTAINED WIND SPEED IS 90 KT WITH GUSTS TO 110 KT. NUMEROUS MODERATE TO STRONG CONVECTION WAS WITHIN 120 NM NW SEMICIRCLE AND 180 NM SE SEMICIRCLE OF THE CENTER OF ANDRES WITH SCATTERED MODERATE CONVECTION FOUND ELSEWHERE FROM 05N TO 10N BETWEEN 112W AND 118W. ANDRES IS FORECAST TO CONTINUE NW AS A HURRICANE THROUGH EARLY MON MORNING...THEN WILL WEAKEN TO A TROPICAL STORM AS IT MOVES INTO COOLER WATERS AND CONTINUE W-NW REACHING 20N130W BY MID WEEK. SWELLS GENERATED BY ANDRES COULD IMPACT THE COAST OF MEXICO BETWEEN CABO CORRIENTES AND LOS CABOS BY THIS EVENING... SPREADING ALONG THE COAST OF BAJA CALIFORNIA ON SUN. REFER TO LATEST NHC PUBLIC/FORECAST ADVISORIES UNDER AWIPS/WMO HEADERS MIATCPEP1/MIATCMEP1 AND WTPZ31/WTPZ21 KNHC FOR MORE DETAILS.


...TROPICAL WAVES/LOWS...

A TROPICAL WAVE EXTENDS FROM 10N TO 16N BETWEEN 101W AND 103W. THE WAVE IS SLOWING AS IT ENCOUNTERS THE BROADER CYCLONIC CIRCULATION ASSOCIATED WITH HURRICANE ANDRES. THE FIRST COUPLE OF VISIBLE IMAGERY OF DAY INDICATE A WEAK LOW MAY BE FORMING AT THE SOUTHERN END OF THE TROPICAL WAVE NEAR 11N101W. SCATTERED MODERATE CONVECTION IS NOTED WITHIN 45 NM OF THE CENTER OF THIS LOW. STRONG UPPER-LEVEL WINDS ASSOCIATED WITH THE HURRICANE ARE CURRENTLY INHIBITING INTENSIFICATION OF THIS LOW...BUT THEY ARE FORECAST TO WEAKEN ALLOWING CONDITIONS TO BECOME MORE CONDUCIVE FOR TROPICAL CYCLONE DEVELOPMENT BY EARLY NEXT WEEK. THE LOW PRES WILL MOVE NW REACHING 12N105W BY LATE SUN...WITH WINDS AND SEAS INCREASING TO THE ADVISORY THRESHOLDS OF 20-25 KT AND 8 FT...RESPECTIVELY.

A 1010 MB LOW PRESSURE SYSTEM WAS ANALYZED NEAR 06N91W WITH A TROUGH EXTENDING NORTHWARD TO 11N91W. SCATTERED MODERATE TO ISOLATED STRONG CONVECTION WAS OBSERVED FROM 02N TO 06N BETWEEN 88W AND 105W. THIS SYSTEM IS EXPECTED TO ENCOUNTER INCREASING NORTHWESTERLY FLOW ALOFT AS IT DRIFTS SLOWLY W-NW OVER THE NEXT TWO DAYS...INHIBITING FURTHER DEVELOPMENT.


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

THE MONSOON TROUGH AXIS WAS ANALYZED FROM 10N118W TO 08N125W TO LOW PRES NEAR 10N138W 1010 MB TO 09N140W. SCATTERED MODERATE WITH ISOLATED STRONG CONVECTION WAS NOTED WITHIN 270 NM S OF THE AXIS BETWEEN 120W AND 135W. SCATTERED MODERATE TO STRONG CONVECTION WAS OBSERVED WITHIN 90 NM W QUADRANT OF THE LOW PRES SYSTEM NEAR 10N138W. THIS LOW IS EXPECTED TO MOVE W-SW AROUND 5 KT OVER THE NEXT TWO DAYS.


...DISCUSSION...

N OF 15N W OF 120W...HURRICANE ANDRES WILL MOVE WITHIN 180 NM SW OF CLARION ISLAND THROUGH SUNDAY. THE APPROACH OF ANDRES WILL WILL WEAKEN AND DISPLACE THE SUBTROPICAL RIDGE WEST OF THE AREA THROUGH EARLY NEXT WEEK...ALLOWING A FAIRLY LIGHT WIND REGIME FOR THE PACIFIC WATERS E OF 120W TO THE COAST OF BAJA CALIFORNIA AND THROUGH THE GULF OF CALIFORNIA. FRESH SWELL GENERATED FROM ANDRES WILL PROPAGATE NORTHWARD...BRING ENHANCED SURF TO THE BAJA COAST THROUGH EARLY NEXT WEEK. FARTHER SOUTH..THE MAIN FORECAST ISSUE WILL BE THE POTENTIAL FOR DEVELOPMENT OF THE LOW PRES STARTING TO FORM NEAR 11N101W. GLOBAL MODELS INDICATE GOOD POTENTIAL FOR TROPICAL CYCLONE DEVELOPMENT EARLY NEXT WEEK. THERE IS SOME DISAGREEMENT REGARDING THE ULTIMATE TRACK OF THIS SYSTEM. THE OFFICIAL FORECAST FOLLOWS THE ECMWF FAVORING A SLOW NORTHWARD DRIFT THROUGH MID WEEK. SEE THE LATEST PACIFIC TROPICAL WEATHER OUTLOOK AT UNDER AWIPS/WMO HEADERS MIATWO3P/ABPZ20 KNHC FOR MORE DETAILS. THE DEEPENING LOW PRES WILL TIGHTEN THE PRES GRADIENT WITH HIGH PRES OVER THE GULF OF MEXICO...INDUCING A ROUND OF FRESH TO STRONG GAP WINDS THROUGH THE GULF OF TEHUANTEPEC BY SUN NIGHT INTO MON MORNING...WITH SEAS TO 8 FT.

S OF 15N W OF 110W...SPEED CONVERGENCE OF SOUTHERLY WINDS INTO THE DEEP TROPICS IS PROMOTING A LINE OF SHOWERS AND THUNDERSTORMS FROM 02N TO 06N BETWEEN 88W AND 105W. GIVEN HIGH MOISTURE VALUES AND THE PERSISTENT SOUTHERLY FLOW THIS CONVECTION WILL PERSIST THROUGH EARLY NEXT WEEK. MEANWHILE 15 TO 20 KT GAP WINDS ARE LIKELY THROUGH THE GULF OF PAPAGAYO TONIGHT INTO SUN MORNING. LONG PERIOD SOUTHERLY SWELL.

ELSEWHERE...A NEGATIVELY TILTED UPPER TROUGH IS MOVING NE ACROSS THE WATERS N OF 23N W OF 130W THIS MORNING...PIVOTING AROUND AN UPPER LOW SITUATED NEAR 35N140W. AN ASSOCIATED FRONTAL BOUNDARY REMAINS STALLED FROM 30N135W TO 27N140W. THIS FRONT WILL START TO LOSE DEFINITION THROUGH THE REMAINDER OF THE DAY AS THE TROUGH LIFTS OUT OF THE AREA. THE MOVEMENT OF THE TROUGH ALONG WITH THE ADVANCE OF ANDRES FROM THE SE HAS SIGNIFICANTLY WEAKENED THE SUBTROPICAL RIDGE IN BETWEEN. THE PRES GRADIENT HAS RELAXED IN THE PAST 24 HOURS FARTHER SOUTH...ALLOWING TRADE WINDS TO DIMINISH AS NOTED IN RECENT ASCAT SATELLITE PASSES. CONCURRENT ALTIMETER SATELLITE PASSES INDICATED RESIDUAL SEAS TO 8 FT PRIMARILY IN FRESH NE SWELL...BUT THIS WILL SUBSIDE SHORTLY. A BROAD AREA OF SWELL RELATED TO ANDRES WILL ENVELOP MUCH OF THE AREA N OF 10N W OF 120W THROUGH MID WEEK.

$$ CHRISTENSEN

Home