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AXPZ20 KNHC 281006
TWDEP

TROPICAL WEATHER DISCUSSION
NWS NATIONAL HURRICANE CENTER MIAMI FL
1005 UTC WED JAN 28 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 0945 UTC.


...SPECIAL FEATURES... GULF OF TEHUANTEPEC GALE WARNING...A PERSISTENT TIGHT PRESSURE GRADIENT ACROSS SOUTHEASTERN MEXICO IS PRODUCING A LONG DURATION EVENT OF N TO NE 30-45 KT WINDS THROUGH THE GULF OF TEHUANTEPEC. SHIP "C6FR3" NEAR 15N94W REPORTED NE WINDS AT 43 KT AT 04 AND 06 UTC. THE GALE WINDS HAVE RAISED THE SEAS IN THE GULF TO THE RANGE OF 11-18 FT. NE SWELLS THAT HAVE PROPAGATED DOWNSTREAM FROM THIS EVENT OVER THE PAST FEW DAYS ARE COMBINING WITH LONG PERIOD NW SWELLS. THE COMBINATION OF THESE SWELLS IS RESULTING IN A LARGE AREA OF SEAS TO 9 FT FROM 04N TO 14N BETWEEN 91W AND 105W...ALSO FROM 04N TO 12N BETWEEN 105W AND 110W AND FROM 07N TO 19N BETWEEN 110W AND 124W. FRESH TRADE WINDS OVER THE WESTERN PORTION OF THIS AREA ARE ALSO HELPING TO MAINTAIN THE SEAS HIGH. MOST RECENT SEA SURFACE TEMPERATURE ANALYSIS REVEALS A COOL POCKET OF WATERS OVER A PORTION OF THE GULF AS WELL AS DOWNSTREAM FROM THE GULF TO NEAR 13N BETWEEN 94W-97W DUE TO UPWELLING EFFECTS.

HIGH PRES CENTERED OVER THE WESTERN GULF OF MEXICO WITH THE ASSOCIATED CULPRIT TIGHT PRES RIDGING STRETCHING SEWD ACROSS SOUTHEASTERN MEXICO IS FORECAST TO GRADUALLY WEAKEN THROUGH THU. THE GALE WINDS ARE EXPECTED TO DECREASE SLIGHTLY THROUGH TONIGHT...AND TO MINIMAL GALE FORCE BY EARLY THU AFTERNOON WITH SEAS SUBSIDING TO AROUND 14 FT AND TO 12 FT THU NIGHT. THE WINDS THEN INCREASE SOME THU NIGHT AND INTO EARLY FRI AS THE RIDGING BECOMES REINFORCED BY ANOTHER RIDGE THAT BUILDS SWD OVER THE FAR WESTERN GULF AND EASTERN MEXICO TERRAIN. SEAS IN THE GULF ARE FORECAST BY THE TAFB/NWPS GUIDANCE TO BUILD TO BACK TO 14 FT ON FRI.

GULF OF PAPAGAYO GALE WARNING...A TIGHTENING PRES GRADIENT BEHIND A SHEAR LINE IN THE WESTERN CARIBBEAN SEA N OF 10N WILL ALLOW FOR NE WINDS FUNNELING THROUGH THE GULF OF PAPAGAYO TO INCREASE TO MINIMAL GALE FORCE BY DAYBREAK THIS MORNING. WINDS WILL DIMINISH BELOW GALE FORCE DURING THE DAYTIME HOURS AND PULSE BACK TO GALE FORCE WITH THE ASSISTANCE OF DRAINAGE FLOW OFF THE MOUNTAINS IN THE LATE NIGHT AND EARLY MORNING HOURS THROUGH THU. SEAS IN AND NEAR THE GULF ARE FORECAST TO BUILD TO THE RANGE OF 8-12 FT THIS AFTERNOON AND THROUGH THU AFTERNOON BEFORE SUBSIDING TO AROUND 9 FT BY LATE THU. NE SWELLS FROM PAPAGAYO WILL CONTINUE TO MERGE WITH THE SWELL FROM THE GULF OF TEHUANTEPEC THROUGH THE FORECAST PERIOD.


...INTERTROPICAL CONVERGENCE ZONE/MONSOON TROUGH... THE MONSOON TROUGH AXIS EXTENDS FROM 02N78W TO 06N85W TO 05N94W WHERE SCATTEROMETER WINDS INDICATE A TRANSITION TO THE ITCZ AXIS EXTENDING TO 04N105W TO 07N114W TO 08N125W AND TO 08N140W. NO SIGNIFICANT DEEP CONVECTION IS NOTED ALONG OR NEAR THE MONSOON TROUGH AND ITCZ AXIS.


...DISCUSSION... A SLOW MOVING...NEGATIVELY TILTED UPPER LEVEL TROUGH IS THE MAIN FEATURE NOTED. IT STRETCHES FROM NEAR 32N130W TO 23N129W TO 16N127W AND TO 09N122W. A SOUTHERLY JET STREAM BRANCH ON THE E SIDE OF THE TROUGH HAS MAX WINDS OF 80-100 KT. THIS IS HELPING TO ADVECT ABUNDANT UPPER MOISTURE...MAINLY IN THE FORM OF BROKEN TO OVERCAST MID AND UPPER CLOUDS NNE ACROSS SOUTHERN BAJA CALIFORNIA AND W CENTRAL MEXICO. UNDERNEATH THIS MOISTURE
...SCATTERED SHOWERS AND ISOLATED TSTMS ARE POSSIBLE FROM 10N- 28N E OF THE TROUGH TO 110W. A SURFACE REFLECTION OF THIS TROUGH IS ANALYZED FROM 16N122W TO 11N123W. LIGHTNING DENSITY DATA INDICATES MULTIPLE LIGHTNING STRIKES WITHIN THE MENTIONED ACTIVITY FROM 13N-18N BETWEEN 119W-123W. THE DEEP LAYERED TROUGH WILL GRADUALLY SHIFT EASTWARD THROUGH THE NEXT 24N-48 HRS WITH THE CLOUDINESS AND MOISTURE TO ITS E GRADUALLY SPREADING OVER MUCH OF BAJA CALIFORNIA AND THE WESTERN PORTION OF MEXICO N OF ABOUT 18N. ELSEWHERE...HIGH PRES OF 1023 MB IS CENTERED NEAR 35N124W MOVING NW 10 KT. A RIDGE EXTENDS FROM THE HIGH SE TO 15N118W AND TO NEAR 18N116W. A WEAK TROUGH EXTENDS FROM 16N135W TO 15N138W.

GAP WINDS... SEE SPECIAL FEATURES ABOVE FOR GULFS OF TEHUANTEPEC AND PAPAGAYO GALE EVENTS.

GULF OF PANAMA...THE TIGHTENING PRES GRADIENT OVER THE WESTERN CARIBBEAN SEA IS RESULTING IN STRONG N WINDS TO FUNNEL SWD THROUGH THE GULF OF PANAMA WITH SEAS TO 8 FT. THESE WINDS ARE FORECAST TO REACH AS FAR S AS 04N BY LATE TONIGHT WITH SEAS BUILDING TO 10 FT...AND LAST THROUGH WED AFTERNOON BEFORE SUBSIDING SLIGHTLY THU NIGHT.

GULF OF CALIFORNIA...THE PRES DIFFERENCE BETWEEN A TROUGH JUST W OF MEXICO ALONG 106W FROM 16N-19N AND HIGH PRES RIDGING JUST W OF BAJA CALIFORNIA WILL INDUCE FRESH TO STRONG NW-N WINDS OFFSHORE OF THE SE TIP OF THE BAJA CALIFORNIA PENINSULA BY DAYBREAK THIS MORNING WITH SEAS TO 8 FT. THE GRADIENT WILL WEAKEN ENOUGH TO ALLOW THESE WINDS TO DIMINISH TO 20 KT OR LESS BY EARLY THU AFTERNOON...THEN INCREASE AGAIN FROM 22N-25N BETWEEN 108W-110W BY LATE THU NIGHT AS RIDGING ACROSS THE EASTERN PACIFIC WATERS STRENGTHENS.

$$ AGUIRRE

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