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000
AXPZ20 KNHC 211605
TWDEP

TROPICAL WEATHER DISCUSSION
NWS NATIONAL HURRICANE CENTER MIAMI FL
1605 UTC FRI NOV 21 2014

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 1545 UTC.


...INTERTROPICAL CONVERGENCE ZONE/MONSOON TROUGH... MONSOON TROUGH AXIS EXTENDS FROM 09N79W TO 10N90W TO LOW PRES NEAR 08N96W 1010 MB TO 08N105W TO LOW PRES NEAR 11N117W 1009 MB TO 07N125W. ITCZ EXTENDS FROM 07N125W TO 08N131W TO BEYOND 08N140W. SCATTERED MODERATE TO STRONG CONVECTION IS WITHIN 120 NM S OF TROUGH BETWEEN 88W-94W. SCATTERED MODERATE/ISOLATED STRONG CONVECTION IS WITHIN 120 NM S OF THE TROUGH BETWEEN 96W- 101W...AND ALSO WITHIN 30 NM OF TROUGH BETWEEN 101W-104W. SCATTERED MODERATE WITHIN 60 NM S OF TROUGH BETWEEN 82W- 88W...AND WITHIN 60 NM OF ITCZ W OF 131W.


...DISCUSSION...

ALOFT...AN UPPER-LEVEL TROUGH SHIFTING EASTWARD EXTENDS SW FROM CENTRAL BAJA CALIFORNIA TO NEAR 23N121W...THEN CONTINUES WESTWARD AS A SHEAR AXIS TO AN ELONGATED UPPER LOW JUST W OF THE AREA AT 24N142W. AN UPPER ANTICYCLONE IS LOCATED NNW OF THE LOW AT 29N143W WITH A RIDGE STRETCHING SEWD IN THE WAKE OF THE TROUGH TO NEAR 25N125W. AS A RESULT...CONFLUENT FLOW INTO THE BASE OF THE TROUGH IS BRINGING SUBSIDENT CONDITIONS WITH RELATED DRY AND STABLE AIR ACROSS THE AREA N OF 19N. SCATTERED TO BROKEN STRATOCUMLUS CLOUDS ARE OBSERVED ON SATELLITE IMAGERY MOVING SSW N OF 17N W OF 126N...AND ALSO N OF 19N NW OF LINE FROM 19N121W TO COAST OF THE BAJA CALIFORNIA PENINSULA. UPPER LEVEL MOISTURE...IN THE FORM OF SCATTERED TO BROKEN HIGH CLOUDS...IS NOTED ON WATER SPILLING S AROUND THE EASTERN PERIPHERY OF THE AFOREMENTIONED ANTICYCLONE...AND INTO THE FAR EASTERN PORTION OF THE AREA NEAR 26N119W. S OF 19N...THE ATMOSPHERE REMAINS VERY MOIST AS NOTED BY THE ACTIVE CONVECTION ALONG AND NEAR THE ITCZ AND MONSOON TROUGH AS DESCRIBED ABOVE. UPPER DIFFLUENCE IS HELPING TO SUSTAIN THE CONVECTIVE ACTIVITY E OF 130W.

AT THE SURFACE...A RIDGE EXTENDS FROM A 1026 MB HIGH LOCATED AT 30N141W TO NEAR 21N119W. THE PRES GRADIENT BETWEEN THE RIDGE AND LOWER PRES IN THE VICINITY OF THE ITCZ IS INDUCING AN AREA OF FRESH TO STRONG TRADE WINDS OVER AN AREA DESCRIBED FROM 10N-23N W OF 130W. THESE WINDS WILL EXPAND SLIGHTLY NORTHWARD AND EASTWARD THROUGH EARLY SAT AS HIGH LIFTS NE AND STRENGTHENS SOME WITH THE ASSOCIATED RIDGE BUILDING MORE FIRMLY SSE OVER THE AREA. THESE WINDS THEN DIMINISH EARLY ON SUN AS THE HIGH AND RIDGE WEAKEN...EXCEPT FROM 09N-15N W OF 133W WHERE A RESIDUAL TIGHT GRADEINT IS EXPECTED TO KEEP FRESH TO STRONG NE-E WINDS THERE WITH SEAS OF 8-10 FT.

A TROUGH IS ANALYZED FROM 15N114W TO LOW PRES OF 1009 MB NEAR 11N117W AND TO 09N118W. THE LOW IS FORECAST TO GRADUALLY WEAKEN TO A TROUGH IN ABOUT 36-48 HRS. FIRST VISIBLE SATELLITE IMAGERY REVEAL THE WEAK CYCLONIC SWIRL OF LOW CLOUDS WITH THE LOW...AND LOW CLOUDS STREAMING TO THE NW E OF THE TROUGH AXIS...AND TO THE SW W OF THE TROUGH AXIS. THE IMAGERY ALSO SHOWS SCATTERED MODERATE ISOLATED STRONG CONVECTION FROM 11N-17N BETWEEN 110W- 115W....AND WITHIN 30 NM OF LINE FROM 11N108W TO 12N110W. SCATTEROMETER DATA FROM LATE LAST NIGHT SHOWED NE WINDS IN THE 20-25 KT RANGE FROM 12N TO 16N W OF THE TROUGH AXIS TO 120W. THIS TROUGH AND LOW WILL MOVE WESTWARD WITH AN AREA OF FRESH TO STRONG NE WINDS AHEAD OF IT...THAT IS FORECAST TO MERGE WITH THE AREA OF THE TRADE WINDS MENTIONED ABOVE IN ABOUT 48 HOURS AND AT WHICH TIME TO LOW IS EXPECTED TO HAVE LOST ITS IDENTITY.

WITH RESPECT TO MARINE ISSUES...LONG PERIOD NW SWELLS DOMINATE MUCH OF THE FORECAST WATERS W OF 124W. THIS SWELL EVENT IS MIXING WITH SWELLS FROM THE S THAT HAVE BEEN LINGERING SINCE THE PAST FEW DAYS. WAVEWATCH GUIDANCE SUGGESTS THAT A NEW SET OF NW SWELLS WILL REACH THE FAR NW CORNER OF THE DISCUSSION AREA BY SAT MORNING. THIS SET OF SWELLS WILL THEN PROPAGATE SEWD ACROSS THE NW AND N CENTRAL WATERS WITHIN THE NEXT 48 HRS WITH SEAS TO 9 FT COVERING THE AREA N OF ABOUT 09N W OF ABOUT 118W.

GAP WINDS...N-NE WINDS OF 20-25 KT ACROSS THE GULF OF TEHUANTEPEC ARE FORECAST TO DIMINISH BELOW 20 KT BY EARLY THIS AFTERNOON WITH SEAS LOWERING TO LESS THAN 8 FT.

LOOKING FURTHER AHEAD...THE NEXT GULF OF TEHUANTEPEC IS FORECAST TO BE A STRONGER ONE. SOME MODELS SUGGEST THAT WINDS MAY POSSIBLY REACH MINIMAL STORM FORCE BY EARLY ON WED MORNING. WAVEWATCH GUIDANCE SUGGESTS BUILDING SEAS UP TO 20-24 FT WITH THIS EVENT. EDITS WILL BE MADE TO THE NDFD GRIDS AS NECESSARY PRIOR TO THIS UPCOMING EVENT.

$$ AGUIRRE

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