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AXPZ20 KNHC 291547
TWDEP

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


...SPECIAL FEATURE...

TROPICAL STORM ANDRES WAS CENTERED NEAR 12.5N 114.6W AT 29/1500 UTC MOVING W-NW OR 295 DEG AT 8 KT. ESTIMATED MINIMAL CENTRAL PRESSURE IS 994 MB. MAXIMUM SUSTAINED WIND SPEED WAS 60 KT WITH GUSTS TO 75 KT. NUMEROUS STRONG CONVECTION WAS WITHIN 90 NM NE SEMICIRCLE OF CENTER WHILE SCATTERED MODERATE TO STRONG CONVECTION WAS ELSEWHERE WITHIN 180 NM OF CENTER...EXCEPT 90 NM N QUADRANT. SCATTERED MODERATE CONVECTION COULD BE FOUND IN THE REMAINDER AREA FROM 05N TO 14N BETWEEN 105W AND 120W. 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...

1010 MB LOW PRES IS CENTERED NEAR 06N88W. SCATTERED MODERATE CONVECTION IS NOTED FROM 03N TO 05N BETWEEN 85W AND 92W. THE LOW PRES IS EXPECTED TO DRIFT SLOWLY N-NW THROUGH 24 HOURS...BUT NOT SIGNIFICANTLY DEVELOP.

A TROPICAL WAVE EXTENDS FROM 07N TO 15N ALONG 101W...AND APPEARS TO BE SLOWLY AND AMPLIFYING SLIGHTLY AS IT DRIFTS WESTWARD CLOSER TO THE TROPICAL CYCLONE. CONVECTION HAS DIMINISHED NEAR THE WAVE AXIS...WITH THE EXCEPTION OF THE NORTHERN END OF THE WAVE NEAR 15N101W WHERE THE WAVE IS INTERACTING WITH MORNING CONVECTION THAT HAS MOVED OFF THE MEXICAN COAST OVERNIGHT. THIS ACTIVITY IS WEAKENING RAPIDLY HOWEVER. A LOW LEVEL CIRCULATION IS BECOMING APPARENT ON SATELLITE IMAGERY RELATED TO THE WAVE...AND TO THE EAST OF A MESOSCALE SURFACE HIGH PRES AREA TO THE EAST OF ANDRES. THE SURFACE LOW WILL DEVELOP AND MOVE IN A N- NW AS THE WAVE PROGRESSES IN THE WAKE ANDRES.

1010 MB LOW PRESSURE IS CENTERED NEAR 10N123W. SCATTERED MODERATE TO STRONG CONVECTION WAS WITHIN 120 NM SW QUADRANT OF CENTER. THIS LOW PRESSURE SYSTEM IS EXPECTED TO DISSIPATE LATER TODAY OR TONIGHT.

1010 MB LOW PRESSURE IS LOCATED NEAR 10N137W. SCATTERED MODERATE WITH ISOLATED STRONG CONVECTION WAS WITHIN 210 NM W SEMICIRCLE OF THE CENTER. 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...

N OF 15N E OF 120W...THE SUBTROPICAL RIDGE CENTERED WEST OF THE AREA WILL WEAKEN THROUGH SUN AND SHIFT WEST AHEAD OF ANDRES APPROACHING FROM THE SE. ASIDE FROM LOCALIZED COASTAL WINDS OVERNIGHT...THE GRADIENT FLOW ACROSS THE BAJA CALIFORNIA COAST AND THROUGHOUT THE GULF OF CALIFORNIA WILL REMAIN FAIRLY LIGHT AS A RESULT. THE CENTER OF ANDRES IS EXPECTED TO PASS WITHIN 210 NM SW OF CLARION ISLAND BY EARLY SUNDAY. THE CURRENT FORECAST CALLS FOR CLARION ITSELF TO REMAIN JUST OUTSIDE OF THE AREA OF TROPICAL STORM FORCE WINDS...BUT WILL SEE 20 TO 30 KT BY SUNDAY. FRESH SWELL GENERATED BY ANDRES WILL BRING 8 TO 10 FT SEAS ACROSS THE AREA BETWEEN 120W AND THE BAJA COAST EARLY NEXT WEEK. FARTHER SOUTH...WEAK RIDGING OVER THE GULF OF MEXICO ALONG WITH LOWER PRES IN THE DEEP TROPICS OF THE EASTERN PACIFIC WILL ALLOW FRESH GAP WINDS INTO THE GULF OF TEHUANTEPEC SAT NIGHT AND SUN NIGHT WITH SEAS TO 7 FT.

S OF 15N E OF 110W...ASIDE FROM THE AFOREMENTIONED LOW PRES AREA NEAR 06N88W...AN EARLIER ASCAT SATELLITE PASS INDICATED FRESH TO STRONG GAP WIND FLOW THROUGH THE GULF OF PAPAGAYO THIS MORNING...BETWEEN A RIDGE OVER THE NW CARIBBEAN AND LOWER PRES ALONG THE DEEP TROPICS OF THE EASTERN PACIFIC.

ELSEWHERE...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 TO E 20 TO 25 KT TRADE WINDS FROM 11N TO 16N W OF 125W 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 10N123W 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 NEAR THE NW CORNER OF THE DISCUSSION AREA NEAR 30N140W. BOTH BOUNDARIES WILL WEAKEN AND DISSIPATE THROUGH TONIGHT.

$$ CHRISTENSEN

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