000
AXPZ20 KNHC 052137
TWDEP 

TROPICAL WEATHER DISCUSSION
NWS TPC/NATIONAL HURRICANE CENTER MIAMI FL
2205 UTC SUN APR 05 2009

TROPICAL WEATHER DISCUSSION FOR THE EASTERN PACIFIC OCEAN
FROM THE EQUATOR TO 32N...EAST OF 140W. 

BASED ON 1800 UTC SURFACE ANALYSIS AND SATELLITE IMAGERY THROUGH 
2130 UTC.

...ITCZ...
THE INTERTROPICAL CONVERGENCE ZONE LIES ALONG A LINE 05N77W TO 
02N100W TO 02N120W TO 04N140W. ISOLATED MODERATE WITHIN 100 NM S 
OF AXIS BETWEEN 89W AND 97W.

...DISCUSSION...
A LATE SEASON GULF OF TEHAUNTEPEC STORM FORCE WIND EVENT WILL BE 
INDUCED BY A COLD FRONT PASSING THROUGH THE BAY OF CAMPECHE 
MONDAY...SENDING STRONG NORTHERLY FLOW THROUGH THE ISTHMUS OF 
TEHUANTEPEC BEGINNING LATE MON AFTERNOON. THE FRONT IS EXPECTED 
TO BE PARTICULARLY STRONG FOR THIS TIME OF THE YEAR. WINDS IN 
THE GULF OF TEHUANTEPEC WILL QUICKLY INCREASE TO STORM FORCE TUE 
MORNING. IN ADDITION...THE PRESSURE GRADIENT BETWEEN LARGE HIGH 
PRESSURE OVER THE GREAT BASIN/SOUTHERN PLAINS OF THE U.S. AND 
LOWER PRESSURES OVER NW MEXICO WILL INDUCE WINDS TO 20 KT OVER 
THE GULF OF CALIFORNIA THIS EVENING. WINDS MAY INCREASE 
FURTHER TO 20 TO LOCALLY 30 KT EARLY MON...BEFORE ENDING MON 
NIGHT. NE WINDS ARE ALSO EXPECTED TO INCREASE TO 20 TO 25 KT 
OVER THE PACIFIC COASTAL WATERS OF COSTA RICA EARLY WED AS THE 
STRONG COLD FRONT CURRENTLY OVER THE FAR NW PORTION OF THE GULF 
OF MEXICO MOVES ACROSS THE WESTERN CARIBBEAN.

A COLD FRONT HAS ENTERED THE FAR NW WATERS. AT 05/1800 UTC...THE 
FRONT ENTERS THE AREA NEAR 30N132W THEN CONTINUES SW TO NEAR  
25N140W. NW SWELL ASSOCIATED WITH THE FRONT IS LAGGING BEHIND... 
HOWEVER SEAS SHOULD BUILD TO THE 10 TO 15 FT RANGE BY THIS 
EVENING. THE DEEP LAYER TROUGH SUPPORTING THIS COLD FRONT IS IN 
THE PROCESS OF CUTTING OFF FROM THE NORTHERN STREAM FLOW WITH A 
COMPLEX UPPER LOW DEVELOPING NEAR 38N135W. THIS UPPER LOW IS 
FORECAST TO DIVE SOUTHEAST THROUGH MON...THEN SLOWLY LIFT 
EAST-NORTHEASTWARD TOWARD CALIFORNIA ON TUE. THE ASSOCIATED COLD 
FRONT WILL BE SLOW TO MOVE EASTWARD AS A RESULT...ALLOWING THE 
NW SWELL TO MOVE AHEAD OF THE SURFACE BOUNDARY BEGINNING MON. NO 
CONVECTION IS ASSOCIATED WITH THIS COLD FRONT AS IT LIES WITHIN 
A VERY DRY AIR MASS GENERALLY N OF 20N W OF 120W. 

AXIS OF THE SUBTROPICAL JET STREAM ORIGINATES SW OF HAWAII AND 
STRETCHES ALONG A LINE FROM 18N140W TO 22N125W TO CENTRAL BAJA 
CALIFORNIA. CORE SPEEDS IS CLOSE TO 100 KT BUT WINDS INCREASE TO 
110-130 KT OVER TEXAS. THIS JET IS ADVECTING MID TO UPPER LEVEL 
MOISTURE EASTWARD ACROSS THE FORECAST AREA...WITH MULTILAYERED 
CLOUDINESS FOUND WITHIN 300 NM SOUTH OF THE JET AXIS NOTED ABOVE.

A WEAK UPPER TROUGH LIES S OF 10N ALONG 117W/118W. EAST OF THIS 
UPPER TROUGH AND SOUTH OF 20N...MUCH OF THIS REGION IS DOMINATED 
BY STRONG SUBSIDENCE ALOFT ASSOCIATED WITH AN ANTICYCLONE 
CENTERED NEAR 13N102W. THIS FEATURE AND THE ASSOCIATED DRY AIR 
MASS ALSO COVERS SE MEXICO AND MOST OF CENTRAL AMERICA WHERE 
MOSTLY FAIR WEATHER PREVAILS.

$$
GR/COBB