000
AXPZ20 KNHC 020240
TWDEP 

TROPICAL WEATHER DISCUSSION   
NWS NATIONAL HURRICANE CENTER MIAMI FL
0405 UTC MON MAY 02 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 
0300 UTC.

...ITCZ...

THE INTERTROPICAL CONVERGENCE ZONE AXIS IS ALONG 09N85W TO 
05N100W TO 08N115W TO 04N130W TO 04N140W. NO SIGNIFICANT 
CONVECTION. A SURFACE TROUGH IS WITHIN THE ITCZ AND EXTENDS FROM 
11N115W TO 05N118W. WIDELY SCATTERED MODERATE CONVECTION IS 
WITHIN 180 NM E AND 120 NM W OF TROUGH AXIS FROM 08N TO 10N.   

...DISCUSSION...
AN UPPER-LEVEL CYCLONE IS NEAR 30N130W WITH AN UPPER TROUGH 
EXTENDING S TO 24N132W THEN SE TO 00N110W. SOUTHWESTERLY FLOW 
ALOFT ON THE EASTERN SIDE OF TROUGH IS TRANSPORTING ABUNDANT
MID TO UPPER LEVEL MOISTURE NORTHEASTWARD PRIMARILY N OF THE 
ITCZ BETWEEN 110W AND 130W. AN UPPER LEVEL ANTICYCLONE IS 
CENTERED AT 10N100W WITH A RIDGE TO THE N OVER SE MEXICO INTO 
THE GULF OF MEXICO. E OF THE UPPER ANTICYCLONE...THE TAIL END OF 
DEEP LAYER TROUGH EXTENDS SW FROM THE WESTERN CARIBBEAN TO 
ACROSS COSTA RICA AND WESTERN PANAMA INTO THE EPAC TO A COL NEAR 
5N100W. DIFFLUENT SOUTHWESTERLY FLOW ALOFT E OF THE UPPER LEVEL 
TROUGH IS SUPPORTING SOME SHOWER ACTIVITY NEAR THE ITCZ E OF 
100W. 

SURFACE HIGH PRES LOCATED N OF THE FORECAST AREA HAS WEAKENED 
SINCE YESTERDAY RESULTING IN DIMINISHING WINDS ACROSS THE N 
WATERS...PARTICULARLY N OF 20N AND W OF THE BAJA CALIFORNIA 
PENINSULA. NE WINDS OF 20 KT ARE STILL BLOWING FROM 08N TO 28N W 
OF 130W...AND FROM 14N TO 20N BETWEEN 120W AND 130W. THE 
SIGNIFICANT WAVE HEIGHTS HAVE ALSO SUBSIDED TO NEAR 9 FT. ONCE 
AGAIN...EXPECT INCREASING WINDS AND SEAS MON NIGHT INTO TUE AS 
HIGH PRES N OF THE FORECAST REGION RESTRENGTHENS. THIS HIGH PRES 
SYSTEM CURRENTLY LOCATED NEAR 35N133W EXTENDS A RIDGE SE ACROSS 
THE FORECAST WATERS TO 20N115W.  

GULF OF CALIFORNIA...TIGHT PRESSURE GRADIENT BETWEEN A COLD 
FRONT OVER NW MEXICO AND HIGH PRES TO THE W OF BAJA CALIFORNIA 
IS SUPPORTING NW WINDS 20 TO 30 KT THROUGH THE GULF OF 
CALIFORNIA. THE NEW RUN OF THE MODEL GUIDANCE SUGGESTS NEAR GALE 
FORCE WINDS MONDAY EVENING. FOR NOW...THE FORECAST INDICATES 
WINDS OF 20 TO 30 KT WITH HIGHER GUSTS. SOME OF THE COASTAL 
CITIES HAVE REPORTED SUSTAINED WINDS OF 20 KT. 
UNFORTUNATELY...THERE HAVE NOT BEEN ANY SCATTEROMETER PASSES TO 
VERIFY THESE WIND SPEEDS. SEAS WILL BUILD TO NEAR 9 FT IN 
CENTRAL WATERS IN THE AREA OF THE LONGEST NW FETCH. THE GRADIENT 
WILL BEGIN TO RELAX EARLY TUE.

GAP WINDS...
GULF OF PAPAGAYO...NE TO E WINDS AT 20 TO 25 KT WILL CONTINUE TO 
PULSE THROUGH THE GULF OF PAPAGAYO OVER THE NEXT COUPLE OF DAYS. 
THE WINDS ARE GREATEST DURING THE OVERNIGHT AND EARLY MORNING 
HOURS WITH THE AID OF THE DRAINAGE FLOW.

GULF OF TEHUANTEPEC...ALL THE ATTENTION REMAINS FOCUSED ON THE 
NEXT GULF OF TEHUANTEPEC WIND EVENT FORECAST TO BE A STRONGER 
ONE. NORTHERLY WINDS AT 20 KT WILL BEGIN TO SURGE INTO THE AREA 
TUE MORNING AND QUICKLY INCREASE TO GALE FORCE LATE TUE. A GALE 
WARNING IS ALREADY IN EFFECT BEGINNING AT 04/0000 UTC. THIS WILL 
BE A LATE SEASON GAP WIND EVENT THAT MAY REACH NEAR STORM FORCE 
TUE NIGHT INTO EARLY WED. SINCE RECORDS WERE KEPT IN 1999...ONLY 
FOUR GALE FORCE WIND EVENTS...WINDS IN THE 35-40 KT RANGE...HAVE 
OCCURRED IN THE MONTH OF MAY. THE LAST GALE FORCE WIND EVENT IN 
THE AREA WAS FOUR WEEKS AGO ENDING 6 APRIL 2011.  

$$
GR