000
AXPZ20 KNHC 270259
TWDEP 

TROPICAL WEATHER DISCUSSION    
NWS TPC/NATIONAL HURRICANE CENTER MIAMI FL
0405 UTC TUE JUL 27 2010

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 
0215 UTC.

...ITCZ...
AXIS ALONG 09N80W TO 11N90W TO 10N101W TO 11N115W TO 11N140W.  
SCATTERED MODERATE TO STRONG CONVECTION WAS NOTED WITHIN 60N AND 
120 NM S OF AXIS E OF 88W. SCATTERED MODERATE TO STRONG 
CONVECTION WAS NOTED WITHIN 60 NM N AND 150 NM S OF AXIS BETWEEN 
91W AND 132W.

...DISCUSSION...
REINFORCED UPPER LEVEL TROUGH ACROSS NW PORTIONS OF THE AREA HAS 
BROADENED PAST 36 HOURS...AND NOW EXTENDS FROM A BROAD BASE NEAR 
32N138W TO 21N130W...WITH BROAD UPPER RIDGE TO THE W. DOWNSTREAM 
BLOCKING RIDGE HAS GRADUALLY WEAKENED AND IS BECOMING MORE NE TO 
SW ELONGATED...WITH UPPER ANTICYCLONE NOW CENTERED AT 27N115W. A 
NARROW MID TO UPPER TROUGH N OF 24N AND ALONG 131/132W SEPARATED 
THE AFOREMENTIONED HIGH WITH A SECOND ANTICYCLONE OVER MEXICO 
NEAR 24N105W...AND WAS PROVIDING EVACUATION FOR DEEP DIURNAL 
CONVECTION ACROSS THE SIERRA MADRES. DRY AND STABLE CONDITIONS 
PREVAILED ACROSS THE REGION N OF 20N W OF 112W AND FROM 15N TO 
20N W OF 130W DUE TO MODERATE TO STRONG SUBSIDENCE.

ZONAL EASTERLY FLOW ALOFT ACROSS THE REMAINDER OF BASIN S OF 20N 
E OF 130W IS ALSO ADVECTING ABUNDANT CONVECTIVE DEBRIS FROM 
CENTRAL AMERICA AND ALONG ITCZ WESTWARD TO 130W. MAIN FORCING 
MECHANISM ACROSS THIS REGION REMAINS LLVL CONVERGENCE ALONG THE 
ITCZ E OF 130W. THE REMNANTS OF TROPICAL WAVE MOVING ACROSS 
CENTRAL CARIBBEAN PAST 24 HOURS HAVE BEEN INTRODUCED ON SURFACE 
MAP AS A SURFACE TROUGH ALONG 88/89W. A TRIO OF WEAK LOW TO MID 
LEVEL CYCLONIC VORTICES IS EVIDENT IN SATELLITE IMAGERY THIS 
EVENING BETWEEN 90W AND 97W. SOME COMPUTER MODEL GUIDANCE 
CONTINUES TO GRADUALLY SPIN UP A LOW PRESSURE CIRCULATION 
DOWNSTREAM BETWEEN 103W AND 112W DURING NEXT SEVERAL DAYS WITH 
POSSIBLE TROPICAL DEVELOPMENT. 

ELSEWHERE AT THE SURFACE...BROAD 1030 MB HIGH PRES WELL NW-N OF 
AREA HAS RIDGE EXTENDING SE-S TO 21N125W.  FRESH NW BREEZE 
CONTINUES TO FUNNEL ALONG THE W COAST OF BAJA CALIFORNIA 
PENINSULA FROM 24N TO 28N.  ADDITIONALLY A WEAK LOW PRES TROUGH 
OVER NW MEXICO HAS TIGHTENED THE PRES GRADIENT OVER GULF OF 
CALIFORNIA AND IS PROMPTING FRESH S BREEZE WITHIN THE GULF THAT 
IS EXPECTED TO CONTINUE THROUGH THE NEXT 24-36 HRS THEN DIMINISH 
BELOW 20 KT.

FRESH TO STRONG WINDS OVER SUBTROPICAL SE PAC CONTINUE TO 
GENERATE LONG PERIOD SE SWELL ENCROACHING INTO E PAC S OF 10N 
WITH SEAS AS HIGH AS 9 FT THROUGHOUT FORECAST PERIOD. 

$$
STRIPLING