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AXPZ20 KNHC 291005
TWDEP

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


...SPECIAL FEATURES... GULF OF TEHUANTEPEC GALE WARNING...A PERSISTENT TIGHT PRES GRADIENT ACROSS SOUTHEASTERN MEXICO JUST INLAND THE GULF CONTINUES TO SUPPORT A LONG DURATION EVENT OF N TO NE 30-40 KT WINDS THROUGH THE GULF OF TEHUANTEPEC. SHIP "ZCDI4" WAS AT POSITION 16N95W AT 00 UTC LAST NIGHT WHEN IT REPORTED NE WINDS OF 37 KT WITH COMBINED SEAS OF 19 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 8-10 FT FROM 04N TO 14N BETWEEN 92W AND 104W...AND ALSO FROM 06N TO 18N BETWEEN 113W AND 127W. FRESH TRADE WINDS OVER THE WESTERN PORTION OF THIS AREA ARE ALSO HELPING TO MAINTAIN THE SEAS HIGH THERE. MOST RECENT SEA SURFACE TEMPERATURE ANALYSIS REVEALS A POCKET OF COOL WATER OVER THE N CENTRAL PART OF THE GULF AS WELL AS DOWNSTREAM FROM THE GULF TO NEAR 12N BETWEEN 94W-97W DUE TO UPWELLING EFFECTS.

THE TIGHT PRES GRADIENT IS FORECAST TO GRADUALLY WEAKEN THROUGH SAT ALLOWING FOR THE GALE WINDS TO DECREASE TO MINIMAL THRESHOLD BY LATE FRI NIGHT...AND TO 20-25 KT BY SAT AFTERNOON WITH SEAS IN THE GULF SUBSIDING TO AROUND 14 FT FRI AND TO 9 OR 10 FT LATE SAT.

GULF OF PAPAGAYO GALE WARNING...A TIGHT PRES GRADIENT OVER THE FAR WESTERN CARIBBEAN SEA ALONG CENTRAL AMERICA IS HELPING TO SET OFF MINIMAL GALE FORCE FORCE THROUGH THE GULF. THESE WINDS WILL DIMINISH BELOW GALE FORCE BY EARLY THIS EVENING...AND PULSE TO 20-30 KT WITH THE ASSISTANCE OF DRAINAGE FLOW OFF THE MOUNTAINS IN THE LATE NIGHT AND EARLY MORNING HOURS THROUGH SAT. SEAS OF 9-11 FT WILL BUILD SLIGHTLY TO 12 FT BY THIS EVENING
...AND SUBSIDE TO 9 FT LATE TONIGHT AND THROUGH LATE FRI NIGHT. 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 ITCZ EXTENDS FROM 01N89W TO 05N90W TO 04N1110W TO 07N125W TO 06N135W TO 07N140W. SCATTERED MODERATE CONVECTION IS WITHIN 120 NM S OF THE ITCZ BETWEEN 117W-120W.


...DISCUSSION... A SLOW MOVING...NEGATIVELY TILTED UPPER LEVEL TROUGH IS THE MAIN FEATURE NOTED OVER THE AREA. IT STRETCHES FROM NEAR 32N124W SSE TO 20N122W TO 12N121W AND TO NEAR 04N112W. A SOUTHERLY JET STREAM BRANCH ON THE E SIDE OF THE TROUGH IS HELPING TO ADVECT ABUNDANT UPPER MOISTURE...MAINLY IN THE FORM OF BROKEN TO OVERCAST MID AND UPPER CLOUDS NNE ACROSS BAJA CALIFORNIA AND THE W CENTRAL AND NW PORTIONS OF MEXICO. UNDERNEATH THIS MOISTURE
...SCATTERED SHOWERS AND ISOLATED TSTMS ARE POSSIBLE N OF 10N E OF THE TROUGH TO JUST INLAND MEXICO. A SURFACE REFLECTION OF THIS TROUGH IS ANALYZED ALONG 125W FROM 20N TO 28N. THE ASCAT PASS FROM 0514 UTC LAST NIGHT INDICATE A WEAK CYCLONIC SWIRL ON THE TROUGH NEAR 26N. LIGHTNING DENSITY DATA INDICATES MULTIPLE LIGHTNING STRIKES WITHIN THE AFOREMENTIONED ACTIVITY FROM 11N- 16N BETWEEN 119W-123W. THE DEEP LAYERED TROUGH WILL GRADUALLY SHIFT EASTWARD THROUGH THE NEXT 48 HRS WITH THE CLOUDINESS AND MOISTURE TO ITS E CONTINUING TO GRADUALLY SPREADING OVER MUCH OF BAJA CALIFORNIA AND THE WESTERN PORTION OF MEXICO N OF ABOUT 18N. ELSEWHERE...NEARLY STATIONARY HIGH PRES OF 1026 MB IS CENTERED N OF THE AREA NEAR 36N130W. THE ASSOCIATED RIDGE EXTENDS FROM THE HIGH SWWD TO W OF 140W AT 29N...WHILE A WEAKER RIDGE EXTENDS SE FROM THE HIGH TO NEAR 21N116W. A WEAK TROUGH EXTENDS FROM 16N135W TO 15N138W. BROAD HIGH PRES AT THE MID/UPPER LEVELS COVERS THE EASTERN PART OF THE AREA TO THE ABOVE DESCRIBED UPPER TROUGH. A MEAN RIDGE AXIS STRETCHES FROM THE CENTRAL U.S. SSE ACROSS CENTRAL MEXICO TO 16N103W AND TO 10N95W. THIS FEATURE IS MAINTAINING DRY AND STABLE ATMOSPHERIC CONDITIONS THROUGH ALL LEVELS OF THE ATMOSPHERE TO THE E OF A LINE FROM JUST S OF MANZANILLO TO THE BASE OF THE UPPER TROUGH.

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 AND TO NEAR 05N WITH SEAS TO 9 FT. THESE WINDS ARE FORECAST TO DIMINISH SLIGHTLY BY LATE TONIGHT...AND TO 20 KT OR LESS BY FRI AFTERNOON WITH SEAS SUBSIDING TO LESS THAN 8 FT.

GULF OF CALIFORNIA...NW WINDS OVER AND NEAR THE SOUTHERN PART OF THE GULF HAVE DIMINISHED SINCE YESTERDAY AS THE GRADIENT BETWEEN HIGH PRES RIDGING OVER THE EASTERN PACIFIC AND TROUGHING OVER THE WESTERN MEXICO SLACKENS. THE RESPITE WILL BE SHORT-LIVED AS THE PRES DIFFERENCE BETWEEN THE TROUGH OVER WESTERN MEXICO AND THE HIGH PRES RIDGING TIGHTENS SOME THIS AFTERNOON AND TONIGHT ALLOWING FOR A RETURN OF FRESH TO STRONG NW WINDS FROM ABOUT 23N TO 26N AND BETWEEN THE BAJA CALIFORNIA PENINSULA COAST AND MEXICO. HOWEVER...THESE WINDS DIMINISH AGAIN TO 20 KT OR LESS ON FRI AFTERNOON.

$$ AGUIRRE

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