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AXPZ20 KNHC 290941
TWDEP

TROPICAL WEATHER DISCUSSION
NWS NATIONAL HURRICANE CENTER MIAMI FL
1005 UTC FRI MAY 29 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 0800 UTC.


...SPECIAL FEATURE...

TROPICAL STORM ANDRES WAS CENTERED NEAR 12.0N 113.9W AT 29/0900 UTC MOVING W-NW OR 295 DEG AT 8 KT. A TURN TOWARD THE NW IS EXPECTED LATER TODAY. ESTIMATED MINIMAL CENTRAL PRESSURE IS 994 MB. MAXIMUM SUSTAINED WIND SPEED WAS 60 KT WITH GUSTS TO 75 KT. NUMEROUS STRONG CONVECTION WAS WITHIN 75 NM NE SEMICIRCLE OF CENTER WHILE SCATTERED MODERATE TO STRONG CONVECTION WAS ELSEWHERE WITHIN 180 NM OF CENTER...EXCEPT 0 NM N QUADRANT. SCATTERED MODERATE CONVECTION COULD BE FOUND IN THE REMAINDER AREA FROM 05N-14N BETWEEN 105W-119W. ANDRES IS FORECAST TO STRENGTHEN OVER THE NEXT 24 HOURS...AND IS EXPECTED TO BECOME A HURRICANE TODAY. 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 06N TO 15N ALONG 101W AND HAS BEEN PROGRESSING W AROUND 10 KT OVER THE PAST 24 HOURS. THE MOST SIGNIFICANT DEEP CONVECTION ASSOCIATED WITH THE WAVE WAS FOUND WITHIN 150 NM S OF THE COAST OF MEXICO BETWEEN 94W AND 103W WHERE SCATTERED MODERATE TO STRONG CONVECTION RESIDED. THE WAVE IS FORECAST TO SLOW TODAY AS IT ENCOUNTERS THE BROADER CYCLONIC CIRCULATION ASSOCIATED WITH TROPICAL STORM ANDRES. LOW PRESSURE IS EXPECTED TO FORM NEAR 11N102W ON SAT AND FOLLOW A N-NW TRACK... POSSIBLY SHOWING GRADUAL INTENSIFICATION OVER THE WEEKEND.

1010 MB LOW PRESSURE IS CENTERED NEAR 09.5N123W. SCATTERED MODERATE TO STRONG CONVECTION WAS WITHIN 150 NM SE QUADRANT OF CENTER WITH SCATTERED MODERATE CONVECTION ELSEWHERE WITHIN 60 NM OF CENTER. THIS LOW PRESSURE SYSTEM IS EXPECTED TO DISSIPATE LATER TODAY OR TONIGHT.

1010 MB LOW PRESSURE IS LOCATED NEAR 10N136W. SCATTERED MODERATE WITH ISOLATED STRONG CONVECTION WAS WITHIN 180 NM W SEMICIRCLE... EXCEPT 270 NM W QUADRANT. THIS LOW IS EXPECTED TO MOVE W-SW AROUND 10 KT OVER THE NEXT TWO DAYS.


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

CURRENTLY THERE IS NOT A WELL DEFINED MONSOON TROUGH OR ITCZ.


...DISCUSSION...

THE PRESSURE GRADIENT BETWEEN THE SUBTROPICAL RIDGE TO THE N AND THE TWO AFOREMENTIONED TROPICAL LOWS W OF 120W IS MAINTAINING AN AREA OF NE-E 20-25 KT TRADES FROM 11.5N TO 16N W OF 124W WITH COMBINED SEAS TO 9 FT. THESE WINDS WERE PARTIALLY CAPTURED BY THE 0620 UTC ASCAT AND 0428 UTC RAPIDSCAT PASSES. THE SUBTROPICAL RIDGE TO THE N IS EXPECTED TO WEAKEN AS LOW PRESSURE INFRINGES UPON IT FROM THE W. IN ADDITION...THE EASTERN LOW PRESSURE SYSTEM NEAR 09.5N123W IS EXPECTED TO DISSIPATE TODAY. THESE CONDITIONS WILL SLACKEN THE PRESSURE GRADIENT AND CAUSE WINDS TO DIMINISH BELOW A FRESH TO STRONG BREEZE OVERNIGHT TONIGHT.

A DEEP-LAYERED LOW CENTERED N-NE OF THE HAWAIIAN ISLANDS HAS MULTIPLE VORTICIES PASSING TO IT S. AT THE SURFACE...TWO DISTINCT BOUNDARIES WERE ANALYZED OVER FORECAST WATERS. ONE FROM 30N137W TO 26N140W AND S SECOND FROM 32N138W TO 20N140W. THE LEAD BOUNDARY SHOULD DISSIPATE TODAY AND THE WESTERN BOUNDARY SHOULD CONTINUE INTO NW WATERS THROUGH THE WEEKEND...EXTENDING FROM 32N136W TO 27N140W EARLY SAT AND FROM 32N134W TO 25N140W EARLY SUN. SCATTERED SHOWERS AND ISOLATED THUNDERSTORMS ARE EXPECTED NEAR THE BOUNDARY. WINDS AND SEAS SHOULD REMAIN BELOW 20-25 KT AND 8 FT...RESPECTIVELY.

GAP WINDS... GULF OF PAPAGAYO...THE 0344 UTC ASCAT PASS CAPTURED 20-25 KT E WINDS IN THE GULF OF PAPAGAYO. FRESH TO STRONG E-NE WINDS FROM 10N-12N E OF 89W ARE EXPECTED TO CONTINUE UNTIL JUST AFTER SUNRISE. THE PRESSURE GRADIENT BETWEEN RIDGING OVER THE NW CARIBBEAN AND A 1010 MB SURFACE LOW JUST TO THE SW NEAR 07N89W IS COMBINING WITH NOCTURNAL DRAINAGE FLOW TO FUNNEL THESE WINDS THROUGH CENTRAL AMERICA AND INTO THE GULF OF PAPAGAYO. THE PRESSURE GRADIENT WILL DIMINISH TODAY AS THE LOW MOVES AWAY FROM THE AREA.

$$ SCHAUER

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