000
AXPZ20 KNHC 040858
TWDEP 

TROPICAL WEATHER DISCUSSION   
NWS NATIONAL HURRICANE CENTER MIAMI FL
1005 UTC MON APR 04 2011

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

BASED ON 0600 UTC SURFACE ANALYSIS AND SATELLITE IMAGERY 
THROUGH 0745 UTC.

...ITCZ...

THE INTERTROPICAL CONVERGENCE ZONE WAS ANALYZED FROM 04N77W TO 
02N90W TO 04N105W TO 02N112 THEN S OF THE EQUATOR NEAR 114W. 
ISOLATED MODERATE CONVECTION WAS WITHIN 240 NM N OF THE ITCZ 
AXIS BETWEEN 82W AND 94W.

...DISCUSSION...

A WEAKENING DEEP LAYERED LOW OVER NW WATERS IS THE DOMINANT 
FEATURE OVER THE FORECAST AREA. THIS LOW HAS TAPPED INTO THE 
TROPICAL MOISTURE ALONG THE ITCZ AND HAS TRANSPORTED IT INTO ITS 
EASTERN SEMICIRCLE WITH MULTI-LAYERED CLOUDINESS AND ASSOCIATED 
SHOWERS FOUND OVER MUCH OF THE REGION N OF 10N BETWEEN 112W AND 
125W. THIS SYSTEM HAS DISRUPTED THE SUBTROPICAL HIGH PRES AND 
THE TRADE WINDS USUALLY FOUND OVER THE AREA. THE 0454 UTC AND 
0634 UTC ASCAT PASSES SHOW WINDS AS HIGH AS 30 KT WHERE THE PRES 
GRADIENT IS TIGHTEST NEAR 26N132W. THESE PASSES ALSO REVEAL THAT 
THE CLOSED LOW CIRCULATION AT THE SURFACE APPEARS TO HAVE OPENED 
UP TO A TROUGH. THIS SYSTEM WILL WEAKEN FURTHER AND THE UPPER 
LOW WILL LIFT NORTHEASTWARD OVER THE NEXT FEW DAYS.

AN ANTICYCLONE ALOFT LIES NEAR 05N98W AND EXTENDS A RIDGE 
EASTWARD TO THE BORDER OF PANAMA AND COLOMBIA. UPPER DIFFLUENCE 
ASSOCIATED WITH THIS RIDGE IS ENHANCING CONVECTION ALONG 
THE ITCZ IN A REGION WHERE PRECIPITABLE WATER VALES ARE AROUND 
50 MILLIMETERS. THIS CONVECTION IS DESCRIBED IN THE ITCZ SECTION 
ABOVE. 

AN UPPER TROUGH FROM 11N111W TO 00N105W IS WEDGED BETWEEN THE 
AFOREMENTIONED ANTICYCLONE AND A RIDGE AXIS OVER SW WATERS FROM 
12N121W TO 00N130W. DIFFLUENCE BETWEEN THE WESTERN RIDGE AND THE 
TROUGH IS ENHANCING CONVECTION N OF THE ITCZ IN THE AREA OF 
INCREASED MID TO LOW LEVEL MOISTURE ON THE SOUTHERN EDGE OF THE 
FLOW INTO THE DEEP LAYERED LOW OVER NW WATERS. ISOLATED MODERATE 
CONVECTION LIES FROM 04N TO 10N BETWEEN 110W AND 120W AS A 
RESULT.

GAP WINDS...
GULF OF TEHUANTEPEC...STRONG HIGH PRES ASSOCIATED WITH A COLD 
FRONT EXPECTED TO SWEEP INTO THE SW GULF OF MEXICO TUE WILL 
INITIATE A BRIEF GALE WIND EVENT TUE EVENING IN THE GULF OF 
TEHUANTEPEC. WINDS WILL REMAIN AT GALE FORCE THROUGH THE END OF 
THE FORECAST PERIOD EARLY WED MORNING BUT ARE EXPECTED TO 
DIMINISH BELOW GALE FORCE AFTER SUNRISE.

GULF OF PAPAGAYO...THE PRES GRADIENT BETWEEN RIDGING TO THE NE 
OVER THE SW N ATLC AND TROUGHING OVER NORTHERN SOUTH AMERICA IS 
GENERATING STRONG NE WINDS IN THE GULF OF PAPAGAYO. SHIP DILE 
REPORTED 27 KT NE WINDS NEAR 10N89W AT 0600 UTC. THE PRES 
GRADIENT WILL SLACKEN TODAY AS THE RIDGE SHIFTS EASTWARD...BUT 
DRAINAGE FLOW INTO THE GULF OF PAPAGAYO WILL HELP KEEP WINDS TO 
ADVISORY CRITERIA THROUGH TUE MORNING.

GULF OF PANAMA...THE PRES GRADIENT BETWEEN CLIMATOLOGICAL LOW 
PRES OVER NE COLOMBIA AND HIGHER PRES OVER CENTRAL AMERICA IS 
FORCING N WINDS TO 20 KT THROUGH THE GULF OF PANAMA THIS 
MORNING. THE 0306 UTC ASCAT PASS CONFIRMED THESE WINDS. WINDS 
WILL DIMINISH BELOW ADVISORY CRITERIA LATER TODAY AS THE HIGH 
PRES SYSTEM RESPONSIBLE FOR THE RIDGING OVER CENTRAL AMERICA 
SHIFTS EASTWARD.

$$
SCHAUER