Tropical Weather Discussion
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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


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