000
AXPZ20 KNHC 311005
TWDEP 

TROPICAL WEATHER DISCUSSION
NWS NATIONAL HURRICANE CENTER MIAMI FL
1005 UTC THU MAY 31 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 ON 0600 UTC SURFACE ANALYSIS AND SATELLITE IMAGERY THROUGH 
0900 UTC.

...INTERTROPICAL CONVERGENCE ZONE/MONSOON TROUGH...

THE MONSOON TROUGH IS ALONG 09N83W TO 08N100W TO 08N117W TO 
06N124W. THE INTERTROPICAL CONVERGENCE ZONE AXIS EXTENDS FROM 
06N124W TO 04N140W. SCATTERED STRONG CONVECTION IS LOCATED 
WITHIN A 90 NM RADIUS OF 06.5N106W. SCATTERED MODERATE ISOLATED 
STRONG CONVECTION IS LOCATED WITHIN 60 NM EITHER SIDE OF A 
08N82W TO 03N81W LINE AND WITHIN A 60 NM RADIUS OF 07N133W. 

...DISCUSSION...

A TROUGH-RIDGE-TROUGH-RIDGE UPPER PATTERN CONTINUES TO SPAN THE 
DISCUSSION AREA THIS MORNING. A WELL-DEFINED MIDDLE/UPPER LEVEL 
CYCLONIC CIRCULATION IS CENTERED NEAR 23N145W...DIGGING SLOWLY 
SW. A JET SEGMENT IS LOCATED ACROSS THE SE SEMICIRCLE OF THIS 
CYCLONE...EXTENDING THROUGH 15N141W TO 24N136W TO 28N133W AND 
THEN TURNS E OVER THE DOWNSTREAM RIDGE...AND WEAKENS AS IT 
CROSSES THE NORTHERN BAJA CALIFORNIA PENINSULA. CORE WIND 
SPEEDS 65-85 KT ARE FOUND N OF 20N. DOWNSTREAM...A LARGE 
MIDDLE/UPPER LEVEL RIDGE COVERS THE AREA FROM 10N TO 30N BETWEEN 
105W AND 128W. THE UPPER CYCLONE IS FORECAST TO BECOME CUT OFF 
FROM AN ASSOCIATED TROUGH AND SHIFT W BEGINNING FRI...WHICH WILL 
ALLOW THE UPPER RIDGE TO SHIFT SLOWLY W IN TURN OVER THE NEXT 
TWO DAYS. DOWNSTREAM OF THE RIDGE...A MIDDLE/UPPER TROUGH 
CONTINUES FROM THE CENTRAL GULF OF MEXICO TO AN ELONGATED 
CYCLONE CENTERED OVER THE YUCATAN PENINSULA...WITH TROUGH 
CONTINUING SW TO 10N103W. NLY FLOW ALOFT ON THE W SIDE OF THE 
TROUGH CONTINUES TO TRANSPORT COLD AIR ALOFT TO THE VICINITY OF 
THE MONSOON TROUGH...AND MAINTAIN A VERY UNSTABLE ATMOSPHERE 
THERE. SOME OF THE STRONGEST CONVECTION NOTED ACROSS THE REGION 
THIS MORNING WAS OCCURRING ACROSS THIS AREA OF THE DEEP TROPICS 
BETWEEN 102W AND 108W. E OF THIS UPPER TROUGH...AN UPPER RIDGE 
WAS CENTERED ON AN ANTICYCLONE OVER THE SW CARIBBEAN ALONG 78W. 

AT THE SURFACE...A RIDGE COVERS THE AREA N OF 15N W OF 
105W...CENTERED ON A 1027 MB HIGH NEAR 35N135W. THE PRES 
GRADIENT BETWEEN THE HIGH AND LOW PRES ACROSS CALIFORNIA AND W 
ARIZONA IS YIELDING FRESH TO STRONG NNW WINDS FROM THE OFFSHORE 
WATERS OF N CALIFORNIA THROUGH THE ENTIRE LENGTH OF COASTAL 
ZONES OF THE BAJA PENINSULA. NW SWELL IS PRODUCING SEAS TO 8 FT 
N OF 28N ACROSS THIS AREA. S OF THE SURFACE RIDGE...FRESH NE 
TRADEWINDS ARE FOUND FROM 09N TO 23N W OF 130W AND ALSO FROM 
FROM 10N TO 13N BETWEEN 123W AND 130W. SEAS HERE ARE RUNNING 6 
TO 8 FT IN A MIX IF NE WIND WAVES AND NW SWELL. THE HIGH WILL 
BEGIN TO SHIFT SLOWLY SW AND WEAKEN SLIGHTLY THIS EVENING AND 
TONIGHT AND REDUCE THE PRES GRADIENT TO THE S...AND THE AREAL 
EXTENT OF THE FRESH TRADES. 

ACTIVE CONVECTION CONTINUES S OF THE MONSOON TROUGH...AS WOULD 
BE EXPECTED...E OF 110W...AND IS DESCRIBED ABOVE. THE E PORTION 
OF THE TROUGH E OF 90W IS FORECAST BY GLOBAL MODELS TO LIFT N TO 
CENTRAL AMERICA AND BREAK FROM THE REMAINDER OF THE TROUGH THIS 
AFTERNOON AS A PERTURBATION ALONG ABOUT 107W CONTINUES MOVING 
W.

LONG PERIOD SOUTHERN HEMI SWELL WILL CROSS THE EQUATOR AND MOVE 
INTO THE AREA WATERS THIS AFTERNOON AND TONIGHT...AND RAISE SEAS 
TO THE 8 TO 10 FT RANGE S OF 08N BY SAT. THIS STRONG SWELL WILL 
AFFECT THE PACIFIC COASTS OF CENTRAL AMERICA SUN AND MON WITH 
HIGH SURF AND WIDESPREAD DANGEROUS RIP CURRENTS.

$$
STRIPLING