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Eastern North Pacific Tropical Weather Discussion (Text)



000
AXPZ20 KNHC 050929
TWDEP 

TROPICAL WEATHER DISCUSSION                                  
NWS NATIONAL HURRICANE CENTER MIAMI FL                      
1005 UTC THU MAY 05 2016

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
0900 UTC.

...SPECIAL FEATURES...

THE 0320 UTC ASCAT PASS REVEALED THE ONSET OF THE LATE SEASON
GULF OF TEHUANTEPEC GAP WIND EVENT SHOWING NORTHERLY WINDS IN
THE 20-25 KT RANGE N OF 15N BETWEEN 94.5W AND 95.5W. WINDS WILL
CONTINUE TO FUNNEL FROM THE GULF OF MEXICO THROUGH THE CHIVELA
PASS INTO THE GULF OF TEHUANTEPEC REACHING NEAR GALE FORCE THIS
MORNING. WINDS WILL FURTHER INCREASE TO MINIMAL GALE FORCE BY
TONIGHT AND CONTINUE INTO EARLY FRI MORNING BEFORE DIMINISHING
BELOW GALE FORCE EARLY FRI AFTERNOON. SEAS WILL BUILD TO NEAR 12
FT WITH THIS GALE FORCE GAP WIND EVENT.

CLIMATOLOGICALLY SPEAKING...THE FINAL GALE FORCE WIND EVENT
OCCURS IN THE GULF OF TEHUANTEPEC IN LATE MARCH OR EARLY APRIL.
SINCE RECORDS WERE KEPT IN 1999...ONLY THREE GALE FORCE WIND
EVENTS...WINDS IN THE 35-40 KT RANGE...HAVE OCCURRED IN THE
MONTH OF MAY. THESE EVENTS COINCIDED WITH EL NINO CONDITIONS
DURING THE PREVIOUS WINTER TIME.

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

THE MONSOON TROUGH EXTENDS FROM 10N90W TO A 1009 MB LOW PRES
NEAR 08N105W TO 07N120W. THE ITCZ CONTINUES FROM 07N120W TO
05N130W TO BEYOND 05N140W. SCATTERED MODERATE CONVECTION IS
NOTED WITHIN 120 NM S OF THE TROUGH BETWEEN 92W AND 97W.
SCATTERED MODERATE ISOLATED STRONG CONVECTION IS FROM 06N TO 09N
BETWEEN 110W AND 115W. SIMILAR CONVECTION IS WITHIN 120 NM N OF
THE ITCZ W OF 138W. 

...DISCUSSION...

A WEAKENING COLD FRONT EXTENDS FROM A WEAK OCCLUDED LOW PRESSURE
OF 1014 MB CENTERED NEAR 31N124W TO 30N122W TO 24N124W TO
20N130W TO 19N140W. AN AREA OF FRESH TO STRONG NORTHERLY WINDS
PERSISTS W OF THE FRONT...PARTICULARLY N OF 26N BETWEEN 128W AND
136W DUE TO THE TIGHT PRES GRADIENT BETWEEN THE LOW AND A 1034
MB HIGH PRES LOCATED NEAR 35N142W. THIS HIGH PRES FOLLOWS THE
FRONT. SCATTEROMETER DATA CONFIRMED THE PRESENCE OF THESE WINDS
WHILE AN ALTIMETER PASS PROVIDED OBSERVATIONS OF SEAS UP TO 13
FT SW OF THE LOW CENTER NEAR 29N130W. THE LOW PRESSURE AREA AND
FRONT WILL DISSIPATE OVER THE NEXT 24 HOURS. BY TONIGHT...
NORTHERLY WINDS OF 20-25 KT AND SEAS OF 9-11 FT WILL CONTINUE TO
AFFECT THE NORTHERN WATERS N OF 27N BETWEEN 123W AND 131W. SEAS
GREATER THAN 8 FT WILL STILL COVER THE FORECAST WATERS N OF 22N
BETWEEN 120W AND 135W BY FRI NIGHT. 

A RIDGE DOMINATES THE REMAINDER OF THE FORECAST REGION N OF 15N
W OF 110W. THE PRES GRADIENT BETWEEN THIS RIDGE AND LOWER
PRESSURE IN THE VICINITY OF THE ITCZ IS SUPPORTING MODERATE TO
LOCALLY FRESH TRADES N OF THE ITCZ AND W OF 120W. HIGH PRESSURE
BUILDING BEHIND THE FRONT WILL BRING SOME INCREASE IN THE TRADE
WIND FLOW OVER THE WEST-CENTRAL WATERS TODAY. MARINE GUIDANCE
SUGGESTS MODERATE TO FRESH TRADE WINDS AND SEAS OF 7-8 FT
THROUGH LATE FRI NIGHT. BY THAT TIME...ADDITIONAL PULSES OF
MIXED SWELL SHOULD REACH THE WESTERN WATERS. 

A WEAK LOW PRES OF 1009 MB ON THE MONSOON TROUGH NEAR 08N105W
CONTINUES TO MOVE WESTWARD. A WEAK CYCLONIC TURNING IS STILL
NOTED IN ASSOCIATION WITH THIS LOW USING NIGHT CHANNEL VISIBLE
IMAGERY. CONVECTION DIRECTLY TIED TO THE LOW REMAINS MINIMAL.
THE LOW IS FORECAST TO DISSIPATE IN 24 HOURS. 

GULF OF CALIFORNIA...A DEVELOPING SURFACE TROUGH OVER SOUTHERN
CALIFORNIA AND NORTHERN BAJA WILL BRING AND INCREASE IN WINDS
AND SEAS ACROSS THE FAR NORTHERN GULF OF CALIFORNIA TODAY. IN
FACT...A RECENT ASCAT PASS SHOWED MODERATE TO LOCALLY FRESH S TO
SW WINDS IN THE GULF N OF 30N W OF 114W. MODERATE TO LOCALLY
FRESH NW WINDS ARE ALSO NOTED JUST OFFSHORE THE W COAST OF BAJA
CALIFORNIA BETWEEN 23N AND 27W. WINDS IN THE NORTHERN GULF OF
CALIFORNIA ARE FORECAST TO INCREASE TO 20-25 KT THIS
AFTERNOON...AND FURTHER INCREASE TO 25-30 KT TONIGHT...BEFORE
DIMINISHING BACK TO 20-25 KT TOWARD DAYBREAK ON FRI. MAX SEAS
ARE EXPECTED TO REACH AROUND 8 FT TONIGHT WITH THE STRONGEST
WINDS.

$$ 
GR

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Page last modified: Thursday, 05-May-2016 09:29:21 UTC