000
AXPZ20 KNHC 010919
TWDEP 

TROPICAL WEATHER DISCUSSION   
NWS NATIONAL HURRICANE CENTER MIAMI FL
1005 UTC SUN MAY 01 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 
0730 UTC.

...ITCZ...

THE INTERTROPICAL CONVERGENCE ZONE AXIS IS ANALYZED FROM 06N87W 
TO 05N101W TO 02N107W TO 05N114W TO 01N131W. SCATTERED MODERATE 
CONVECTION WAS BETWEEN 90 NM AND 180 NM S OF THE ITCZ AXIS 
BETWEEN 84W AND 92W AS WELL AS WITHIN 30 NM N AND 90 NM S OF THE 
ITCZ AXIS BETWEEN 109W AND 113W. A TROUGH IS EMBEDDED IN THE 
ITCZ FROM 10N113W TO 02N116W. SCATTERED MODERATE CONVECTION WAS 
WITHIN 90 NM E OF THE TROUGH N OF 08N AND BETWEEN 75 NM AND 180 
NM W OF THE TROUGH FROM 06N TO 09N.

...DISCUSSION...
THE SUBTROPICAL HIGH IS CURRENTLY SEVERED BY A WEAKENING COLD 
FRONT CURRENTLY NW OF THE AREA. THE 1033 MB EASTERN HIGH CENTER 
NEAR 45N130W WILL SHIFT SOUTHWARD AHEAD OF THIS FRONT AND WEAKEN 
TODAY. ON MON...THE FRONT WILL DISSIPATE AND THE HIGH PRES W OF 
THE FRONT WILL BECOME THE DOMINANT HIGH. THE 0535 UTC ASCAT PASS 
SHOWS A LARGE AREA OF FRESH TO STRONG WIND IN N WATERS. N SWELL 
TO 12 FT CAN BE FOUND WITHIN THIS AREA. AS THE SUBTROPICAL HIGH 
REORGANIZES OVERNIGHT TONIGHT...WINDS AND SWELL WILL DIMINISH 
OVER MUCH OF THE AREA BUT WILL BEGIN TO RETURN LATE MON AS THE 
NEW DOMINANT HIGH STRENGTHENS AND MOVES EASTWARD. A BLANKET OF 
STRATOCUMULUS LIES OVER WATERS N OF 20N W OF 115W ACCORDING TO 
SATELLITE IMAGERY. SOUTHWESTERLY FLOW ALOFT ON THE EASTERN SIDE 
OF TROUGH THAT EXTENDS FROM AN UPPER LOW NEAR 29N132W TO 24N134W 
TO 00N120W IS TRANSPORTING MOISTURE NORTHEASTWARD AND IS 
MANIFESTED AS CIRRUS CLOUDS FOUND PRIMARILY N OF THE ITCZ 
BETWEEN 120W AND 133W. THIS LOW AND TROUGH ARE FORECAST TO MOVE 
SLOWLY EASTWARD INTO TUE MORNING.

A SURFACE TROUGH IS EMBEDDED IN THE ITCZ FROM 10N113W TO 
02N116W. CONVECTION NEAR THIS TROUGH IS DESCRIBED IN THE ITCZ 
SECTION ABOVE. CONVECTIVE BLOW OFF FROM THIS TROUGH IS BEING 
TRANSPORTED TO THE NE BY THE SOUTHWESTERLY WINDS ON THE E SIDE 
OF THE AFOREMENTIONED UPPER TROUGH. AN ANTICYCLONE ALOFT LIES 
NEAR 10N100W AND EXTENDS A RIDGE AXIS NORTHEASTWARD TO ACAPULCO 
AND THROUGH THE WESTERN GULF OF MEXICO. TO ITS E...A POSITIVELY 
TILTED UPPER TROUGH LIES ACROSS COSTA RICA TO NEAR 05N97W. THE 
ANTICYCLONE IS NOT EXPECTED TO MOVE MUCH OVER THE NEXT FEW 
DAYS...KEEPING THE PATTERN OVER THE TROPICS RATHER STAGNANT.

GAP WINDS...
GULF OF PAPAGAYO...FRESH NE FLOW THROUGH THE GULF OF PAPAGAYO 
WILL PULSE THROUGH MON. THE EARLY MORNING HOURS WILL BE THE MOST 
LIKELY TIME TO SEE WINDS AT ADVISORY CRITERIA WITH THE AID OF 
DRAINAGE FLOW. WINDS WILL INCREASE BY TUE MORNING OVER THE SW 
CARIBBEAN AND FUNNEL THROUGH NORTHERN COSTA RICA INTO THE 
PACIFIC. STRONG WINDS ARE EXPECTED TUE MORNING.

GULF OF CALIFORNIA...A TIGHT PRES GRADIENT BETWEEN A COLD FRONT 
OVER NORTHERN MEXICO AND HIGH PRES OVER THE NE PACIFIC AND OVER 
THE U.S. BEHIND THE FRONT WILL RESULT IN STRONG TO NEAR GALE NW 
FLOW ACROSS THE MUCH OF THE GULF OF CALIFORNIA DURING THE NEXT 
COUPLE OF DAYS. FETCH ALONG THE LENGTH OF THE GULF WILL ALLOW 
SEAS TO REACH 8 FT.

$$
SCHAUER