000
AXPZ20 KNHC 281541
TWDEP 

TROPICAL WEATHER DISCUSSION
NWS TPC/NATIONAL HURRICANE CENTER MIAMI FL
1605 UTC WED MAY 28 2008

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

BASED ON 1200 UTC SURFACE ANALYSIS AND SATELLITE IMAGERY THROUGH 
1515 UTC.

...SPECIAL FEATURES...
SURFACE LOW PRES...POSSIBLE TRPCL CYCLONE WITHIN NEXT 36-48 HRS 
...AT 10N88W 1006 MB GETTING MORE LOW LEVEL ORGANIZATION WHILE 
SLOWLY IMPROVING UPPER LEVEL OUTFLOW.  LITTLE MOVEMENT AT THIS 
TIME BUT SYSTEM IS EXPECTED TO DRIFT NE AS SECOND LOW PRES OVER 
SW CARIBBEAN INTERACTS WITH IT.  ASSOCIATED STRONG CONVECTION 
AFFECTS S NICARAGUA AND MOST OF COSTA RICA AND PANAMA.  
CONDITIONS BECOMING MORE FAVORABLE FOR FURTHER STRENGTHENING 
WITH PLENTY OF WARM MOIST TRPCL AIR MASS INFLUX FROM THE SW.
WIND INCREASING TO 25 KT AND GUSTY WITHIN 150 NM S AND SE 
QUADRANTS.  HEAVY RAINFALL POTENTIAL EXPECTED OVER MUCH OF 
CENTRAL AMERICA S OF MEXICO TO PANAMA WITHIN NEXT 48 HOURS. 

INTERACTION BETWEEN BOTH LOW PRES CENTERS ADDS UNCERTAINTY TO  
DEVELOPMENT FORECAST AND THEIR TRACKS...BUT PROXIMITY TO LAND 
AREAS COULD CURTAIL SIGNIFICANT DEVELOPMENT OF EITHER ONE FOR 
THE TIME BEING.  COMPOUNDING THE SCENARIO IS TRPCL WAVE ALONG 
80W DISCUSSED BELOW WHICH IS LIKELY BOOST THE PROBABILITY OF 
INTENSIFICATION AS MUCH AS TO THE UNCERTAINTY OF ANY FORECAST.  

...TROPICAL WAVES...
TROPICAL WAVE ALONG 80W S OF 18N MOVING W AT 15 KT ENTERED E PAC 
EARLY THIS MORNING EXPECTED TO COMPLICATE TROPICAL DEVELOPMENT 
AS EXPLAINED ABOVE.

...ITCZ...
INTERTROPICAL CONVERGENCE ZONE ALONG 07N89W TO 04N100W TO 
05N113W 00N132W.  SCATTERED MODERATE CONVECTION WITHIN 90 NM S 
OF AXIS FROM 91W-108W.  SCATTERED MODERATE CONVECTION WITHIN 
45 NM S OF AXIS FROM 110W-122W.

...DISCUSSION...
MID/UPPER LEVEL TROUGH EXTENDS SWD INTO E PAC FROM 32N125W TO  
26N140W SHIFTING NE AS WELL-ANCHORED ANTICYCLONE AT 22N105W 
REFUSES TO BUDGE.  COMBINATION OF SUBSIDENCE UNDER RIDGE AND 
CONVERGING WIND FLOW ALOFT WITH TROUGH PRODUCING VERY DRY AIR 
MASS W OF 110W AND N OF 15N E OF 110W.

VERY NARROW UPPER LEVEL TROUGH FROM YUCATAN PENINSULA TO 06N103W 
DECOUPLES ABOVE MENTIONED RIDGE FROM RIDGE OVER CARIBBEAN AND 
NRN SOUTH AMERICA.  THE LATTER RIDGE SEEMS TO BE ENHANCING UPPER 
DIFFLUENCE RIGHT OVER BOTH LOW PRES CENTERS MENTIONED IN SPECIAL 
FEATURES SECTION EFFECTIVELY PERMITTING FURTHER INTENSIFICATION.

ELSEWHERE AT THE SURFACE...WEAK 1017 MB HIGH PRES CENTER AT 
28N127W HAS RIDGE EXTEND TO 15N115W NOT STRONG ENOUGH TO SUPPORT 
NE TRADES WHICH HAVE DIMINISHED BELOW 20 KT...BUT SQUEEZES PRES 
GRADIENT AGAINST CALIFORNIA COAST PRODUCING STRONG AND GUSTY NW 
WINDS TO 2O KT.  THESE WINDS ARE EXPECTED TO EXTEND THROUGH 
FORECAST PERIOD.  

LOW PRES AREA MENTIONED IN SPECIAL FEATURES WILL BRING STRONG 
NLY FLOW ACROSS BAY OF CAMPECHE AS IT DRIFTS N WHICH COULD BRING 
STRONG WINDS INTO GULF OF TEHUANTEPEC WITHIN 24 HOURS. 

$$
WALLY BARNES