000
AXPZ20 KNHC 030307
TWDEP 

TROPICAL WEATHER DISCUSSION   
NWS NATIONAL HURRICANE CENTER MIAMI FL
0405 UTC TUE MAY 03 2011

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

BASED ON 0000 UTC SURFACE ANALYSIS AND SATELLITE IMAGERY THROUGH 
0315 UTC.

...ITCZ...

THE INTERTROPICAL CONVERGENCE ZONE AXIS IS ANALYZED ALONG  
06N77W TO 05N86W TO 07N97W TO 04N112N TO 06N122W TO 03N140W. 
SCATTERED MODERATE WITHIN 180 NM OF THE AXIS W OF 100W.

...DISCUSSION...
AN UPPER CYCLONE IS FILLING NEAR 28N131W WITH AN UPPER TROUGH 
EXTENDING SE TO A BASE AT 05N108W. UPPER MOISTURE IS NOTED N OF 
30N WITHIN ABOUT 300 NM OF THE CYCLONE...BUT THE UPPER LEVELS 
APPEAR DRY WITHIN 150 NM W OF THE UPPER TROUGH. AN UPPER LEVEL 
ANTICYCLONE IS CENTERED AT 14N96W WITH A RIDGE NW AND CRESTING 
AT 30N124W. UPPER DIFFLUENCE BETWEEN THE UPPER TROUGH AND THIS 
RIDGE IS ENHANCING CONVECTION IN THE DEEP TROPICS S OF 11N 
BETWEEN 100W AND 120W. THE DEBRIS MOISTURE SPREADS N MERGING 
WITH ADDITIONAL UPPER MOISTURE NOTED UNDER THE UPPER RIDGE. SOME 
OF THIS MOISTURE IS SPREADING NE ACROSS OLD MEXICO. THIS 
PATTERN SHOULD SHIFT SLIGHTLY NORTHEASTWARD OVER THE NEXT 24 
HOURS. THE UPPER LEVELS APPEAR VERY DRY ELSEWHERE S OF 20N E OF 
100W.

AT THE LOW LEVELS...FLOW IS DOMINATED BY A SURFACE HIGH WELL 
NORTH OF OUR AREA WITH A MODERATE GRADIENT ON THE EQUATORWARD 
SIDE CAUSING UP TO 20 KT NE TRADEWINDS. ACCOMPANYING THIS ARE 
HIGH SEAS OF UP TO 10 FT IN MIXED NW SWELL AND NE WIND WAVES. IN 
ABOUT 48 HOURS...THE GRADIENT WEAKENS SOME AND THE AREA OF 20 KT 
NE TRADES CONTRACTS NORTHWARD.
 
A WEAK SURFACE TROUGH IS PRESENT SOUTH OF 10N ALONG 118W AS 
SHOWN IN AN EARLIER ASCAT SCATTEROMETER PASS. HOWEVER...THE 
WINDS REMAIN LESS THAN 20 KT IN ASSOCIATION WITH THIS SYSTEM AND 
CONVECTION IS IS MINIMAL. IT IS NOT LIKELY THAT A PRE-SEASON 
TROPICAL CYCLONE FORMATION WILL OCCUR WITH THIS DISTURBANCE.

GULF OF CALIFORNIA...A TIGHT PRESSURE GRADIENT IS SUPPORTING 
NW WINDS 20 TO 30 KT OVER THE ENTIRE GULF THIS AFTERNOON.  THE 
18Z GFS BACKED OFF ON EARLIER RUNS AND NO LONGER PREDICTS GALE 
FORCE CONDITIONS OCCURRING THIS EVENING. ALL MODELS...WITH THE 
EXCEPTION OF THE NAM WHICH IS QUITE LOW...INDICATE A PEAK OF 25 
TO 30 KT THROUGH WEDNESDAY MORNING. FORCING WILL WEAKEN RATHER 
QUICKLY AND WINDS SHOULD DROP BELOW OUR 20 KT THRESHOLD BY 
WEDNESDAY EVENING.
   
GULF OF PAPAGAYO...NE TO E WINDS AT 20 TO 25 KT WILL CONTINUE TO 
PULSE THROUGH WEDNESDAY IN THE AREA FROM 09N TO 12N E OF 92W.  
WINDS AND SEAS HIGHEST LATE NIGHT AND EARLY MORNING HOURS.

GULF OF TEHUANTEPEC...NORTHERLY WINDS SHOULD BEGIN TO SURGE INTO 
THE NORTHERN GULF AT 20 TO 25 KT AROUND SUNRISE TUESDAY MORNING 
BUT QUICKLY INCREASE TO GALE FORCE TUESDAY EVENING. GAP WIND 
EVENT EXPECTED TO PEAK LATE TUESDAY NIGHT THROUGH EARLY 
WEDNESDAY MORNING. GALE CONDITIONS WILL CONTINUE THROUGH EARLY 
THURSDAY MORNING THEN DIMINISH. THERE IS POTENTIAL FOR THESE 
NORTHERLY WINDS TO REACH MINIMAL STORM FORCE BRIEFLY...AND THE 
18Z GFS EXPLICITLY FORECASTS 45 KT AT 06Z WEDNESDAY. THIS IS  
SIGNIFICANT AS GALE EVENTS IN THE MONTH OF MAY ARE RARE...AND 
STRONG GALE AND MINIMAL STORM FORCE EVENTS ARE VERY RARE.

$$
LANDSEA