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000
AXPZ20 KNHC 300931
TWDEP

TROPICAL WEATHER DISCUSSION
NWS NATIONAL HURRICANE CENTER MIAMI FL
1005 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 0600 UTC SURFACE ANALYSIS AND SATELLITE IMAGERY THROUGH 0700 UTC.


...SPECIAL FEATURE...

HURRICANE ANDRES WAS CENTERED NEAR 14.0N 115.6W AT 30/0900 UTC MOVING NW OR 325 DEG AT 6 KT. ESTIMATED MINIMAL CENTRAL PRESSURE WAS 978 MB. MAXIMUM SUSTAINED WIND SPEED INCREASED TO 80 KT WITH GUSTS TO 100 KT. NUMEROUS MODERATE TO STRONG CONVECTION WAS WITHIN 90 NM OF THE CENTER OF ANDRES WITH SCATTERED MODERATE CONVECTION FOUND ELSEWHERE N OF 07N TO A LINE FROM 18N110W TO 11N119W BETWEEN 110W AND 119W. ANDRES IS FORECAST TO TAKE A W-NW TURN BY TONIGHT. AFTERWARD...ANDRES IS EXPECTED TO STEADILY WEAKEN THROUGH MON MORNING AS IT MOVES OVER COOLER WATERS. 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 ALONG 102W. THE WAVE IS SLOWING AS IT ENCOUNTERS THE BROADER CYCLONIC CIRCULATION ASSOCIATED WITH HURRICANE ANDRES. SCATTERED MODERATE CONVECTION WAS WITHIN 210 NM EITHER SIDE OF THE WAVE FROM 10N-14N. STRONG UPPER-LEVEL WINDS ASSOCIATED WITH THE HURRICANE ARE CURRENTLY INHIBITING INTENSIFICATION...BUT THEY ARE FORECAST TO WEAKEN ALLOWING CONDITONS TO BECOME MORE CONDUCIVE FOR TROPICAL CYCLONE DEVELOPMENT BY EARLY NEXT WEEK. LOW PRESSURE IS EXPECTED TO FORM ALONG THE LOW BY EARLY SUN...WITH WINDS AND SEAS INCREASING TO THE ADVISORY THRESHOLDS OF 20-25 KT AND 8 FT...RESPECTIVELY...BY SUN AFTERNOON.

A 1010 MB LOW PRESSURE SYSTEM WAS ANALYZED NEAR 06N91W WITH A TROUGH EXTENDING NORTHWARD TO 11N19W. SCATTERED MODERATE WITH ISOLATED STRONG CONVECTION WAS BETWEEN 60 NM AND 240 NM SW QUADRANT OF THE LOW. THIS SYSTEM IS EXPECTED TO ENCOUNTER INCREASING NORTHWESTERLY FLOW ALOFT OVER THE NEXT TWO DAYS. THIS SHOULD INHIBIT FURTHER DEVELOPMENT OF THE SYSTEM AS IT TRACKS NW AROUND 10-15 KT.


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

THE MONSOON TROUGH AXIS WAS ANALYZED FROM 10N119W TO 07N125W TO 10N135W TO LOW PRES NEAR 10N138W 1010 MB TO 09N140W. SCATTERED MODERATE WITH ISOLATED STRONG CONVECTION WAS S OF THE AXIS TO 02N BETWEEN 119W-136W. SCATTERED MODERATE WITH ISOLATED STRONG CONVECTION WAS WITHIN 180 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...

A DEEP-LAYERED LOW CENTERED NE OF THE HAWAIIAN ISLANDS HAS TURNED NEGATIVE TILT ALOFT AND REFLECTS A FRONT AT THE SURFACE FROM 1013 MB LOW PRESSURE NEAR 36N140W TO 36N133W TO 30N134W TO 26N140W. THE FRONT WILL WEAKEN AS IT SLOWLY PROGRESSES SOUTHEASTWARD...DISSIPATING FROM 32N129W TO 23N140W EARLY MON MORNING. SCATTERED SHOWERS ARE EXPECTED NEAR THE FRONT. WINDS AND SEAS SHOULD REMAIN BELOW 20-25 KT AND 8 FT...RESPECTIVELY.

THE PRESSURE GRADIENT BETWEEN THE SUBTROPICAL RIDGE TO THE N AND THE AFOREMENTIONED LOW PRESSURE SYSTEM ALONG THE MONSOON TROUGH NEAR 10N138W IS MAINTAINING AN AREA OF NE-E 20-25 KT TRADES WITHIN 330 NM N AND NW QUADRANTS OF THE LOW WITH COMBINED SEAS TO 9 FT. THESE WINDS WERE CAPTURED BY THE 0508 UTC RAPIDSCAT AND 0300 UTC WINDSAT PASSES. THE SUBTROPICAL RIDGE TO THE N WILL CONTINUE TO WEAKEN AS THE FRONT INFRINGES UPON IT FROM THE W THIS WEEKEND. THESE CONDITIONS WILL SLACKEN THE PRESSURE GRADIENT AND CAUSE WINDS TO DIMINISH BELOW A FRESH TO STRONG BREEZE LATER TODAY. THE SUBTROPICAL RIDGE WILL REBUILD FROM THE W BY MON AS THE FRONT TO THE N DISSIPATES. AT THE SAME TIME... THE LOW WILL APPROACH THE WESTERN BORDER OF THE AREA. STRENGTHENING TRADES NEAR THE LOW SHOULD LIE PRIMARILY W OF THE FORECAST AREA.

A NEW BATCH OF LONG PERIOD SW SWELL IS FORECAST TO CROSS THE EQUATOR OVER CENTRAL WATERS SUN. PERIODS WILL BE IN THE 19-21 SECOND RANGE ON THE LEADING EDGE OF THIS SWELL TRAIN. SEAS ARE EXPECTED TO BUILD TO 9 FT PRIMARILY IN WATERS S OF 04N BETWEEN 110W-125W BY EARLY MON MORNING.

GAP WINDS... GULF OF TEHUANTEPEC...THE GRADIENT BETWEEN RIDGING OVER NE MEXICO AND LOWER PRESSURE BOTH TO THE S IN THE DEEP TROPICS OF THE EASTERN PACIFIC AND TO THE E ASSOCIATED WITH NOCTURNAL TROUGHING MOVING W OFF THE YUCATAN PENINSULA EACH NIGHT WILL ALLOW FRESH TO STRONG GAP WINDS TO PULSE IN THE GULF OF TEHUANTEPEC WITH THE HELP OF NOCTURNAL DRAINAGE FLOW EARLY SUN AND EARLY MON WITH SEAS TO 7-9 FT.

$$ SCHAUER

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