000
AXPZ20 KNHC 261540
TWDEP 

TROPICAL WEATHER DISCUSSION    
NWS NATIONAL HURRICANE CENTER MIAMI FL
1605 UTC THU APR 26 2012

TROPICAL WEATHER DISCUSSION FOR THE EASTERN PACIFIC OCEAN FROM 
THE EQUATOR TO 32N...EAST OF 140W. THE FOLLOWING INFORMATION IS 
BASED ON SATELLITE IMAGERY...WEATHER OBSERVATIONS...RADAR...AND 
METEOROLOGICAL ANALYSIS.

BASED 1200 UTC SURFACE ANALYSIS AND SATELLITE IMAGERY THROUGH 
1500 UTC.

...INTERTROPICAL CONVERGENCE ZONE/MONSOON TROUGH...
MONSOON TROUGH FROM 04N77W TO 03N80W TO 07N85W TO 05N94W TO 
07N104W THEN ITCZ TO 07N106W TO LOW PRES AT 06N110W 1010 MB TO 
02N140W.  SCATTERED MODERATE TO STRONG CONVECTION WITHIN 60 NM  
S OF MONSOON TROUGH E OF 81W.  SCATTERED MODERATE ISOLATED 
STRONG CONVECTION WITHIN 210 NM OF AXIS FROM 90W TO 115W.

...DISCUSSION...
VIGOROUS SHORT WAVE ALOFT SWEEPS AWAY DEEP LAYER CYCLONE INLAND 
WITH SHARP UPPER LEVEL LONG WAVE TROUGH EXTENDING FROM 32N117W 
TO 12N140W.  VERY DRY AIR MASS KEEPS SCATTERED TO BROKEN 
STRATIFIED CLOUDS W OF AXIS.  REMNANTS OF COLD FRONT REACH 
NORTHERN BAJA CALIFORNIA PENINSULA WITH LOW PRES CENTER JUST 
MOVING INLAND SOUTHERN CALIFORNIA BRINGING ABUNDANT MOISTURE TO 
REGION.  SECOND WEAKER SHORT WAVE USHERS ANOTHER COLD FRONT INTO 
REGION...THIS ONE FROM 32N132W TO 31N140W...BUT NOT MUCH IMPACT 
ON BASIN AS IT TURN NE QUICKLY FOLLOWING ITS UPPER LEVEL SUPPORT.

SHARP UPPER LEVEL RIDGE HOLDS TO ITS POSITION ALONG 105W AS IT 
IS BLOCKED ON E SIDE BY SECOND TROUGH ALOFT DIGGING SW FROM SE 
MEXICO TO DEVELOPING UPPER LEVEL CYCLONE AT 09N100W.  DRY AIR 
MASS WITHIN 5 DEG OF TROUGH AXIS...BUT PLENTY OF MOISTURE ALONG 
ITCZ WHERE ELONGATED E-W RIDGING ENHANCES ITCZ CONVECTION FROM 
90W TO 115W.

...ELSEWHERE AT THE LOWER LEVELS...
HEALTHY HIGH PRES 1028 MB BUILDS BEHIND SECOND COLD FRONT ALONG 
140W PRESSING GRADIENT AGAINST CALIFORNIA COASTAL TERRAIN 
PROMPTING FRESH TO STRONG NW BREEZE WITHIN 180 NM OFFSHORE AND 
GULF OF CALIFORNIA TODAY AND FRI THEN SPREADING W IN THE WEEKEND 
AS RIDGE STRENGTHENS.  STRONGER RIDGE ALSO BRINGS INCREASED NE 
TRADES FROM 08N TO 25N W OF 130W LATE FRI AND BEYOND.  DECAYING 
8-9 FT NW SWELLS W OF 130W TRAVEL S BUT GET REINFORCED BY 
INCREASING NE TRADES AND BUILD TO 10 FT LATE FRI AND BEYOND.

WEAK LOW PRES CENTER 1010 MB AT 06N110W PRODUCING SCATTERED 
MODERATE TO STRONG CONVECTION IS ENHANCED BY WEAK UPPER LEVEL 
DIFFLUENT PATTERN DUE TO ELONGATED E-W RIDGING ALONG ITCZ.
MODEL GUIDANCE MAINTAINS FAVORABLE ENVIRONMENT FOR LOW PRES TO 
STRENGTHEN FURTHER THROUGH NEXT WEEK...BUT CERTAINTY REMAINS IN 
DOUBT AT THIS TIME. 

GAP WINDS...
EASTWARD DRIFT OF HIGH PRES OVER GULF OF MEXICO VEERED WIND FLOW 
ACROSS ISTHMUS OF TEHUANTEPEC EFFECTIVELY SHUTTING DOWN THE 
FUNNELING OF STRONG WINDS ACROSS CHIVELAS PASS.  WINDS ACROSS 
GULF OF TEHUANTEPEC EXPECTED TO DIMINISH BELOW 20 KT TODAY.  
SIMILARLY AS THE HIGH PRES MOVES...GRADIENT OVER CARIBBEAN SEA 
RELAXES AND DIMINISHES WINDS BLOWING ACROSS CENTRAL AMERICA 
DIMINISHING WINDS OVER GULFS OF PAPAGAYO AND PANAMA LATER TODAY.

$$
WALLY BARNES