000
AXPZ20 KNHC 190938 CCA
TWDEP 

TROPICAL WEATHER DISCUSSION
NWS TPC/NATIONAL HURRICANE CENTER MIAMI FL
1005 UTC THU JUN 19 2008

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 
0900 UTC.

...TROPICAL WAVES...
WEAK TROPICAL WAVE S OF 16N ALONG 96W MOVING W 10 TO 15 KT. 
POSITION BASED UPON EXTRAPOLATION.  

...ITCZ...
INTERTROPICAL CONVERGENCE ZONE 06N77W TO 07N90W TO 11N102W TO 
09N117W TO 07N130W TO 06N140W. SCATTERED MODERATE CONVECTION IS 
WITHIN 180 NM S OF AXIS BETWEEN 93W AND 103W. SCATTERED MODERATE 
CONVECTION IS WITHIN 120 NM N OF AXIS FROM 107W TO 110W.

...DISCUSSION...
BETWEEN FRI LAST WEEK AND WED THIS WEEK A STRONG PRESSURE 
GRADIENT BETWEEN CLIMATOLOGICAL LOW PRESSURE OVER THE DESERT SW 
AND SURFACE HIGH PRESSURE OVER THE NE PACIFIC WAS GENERATING 
NEAR-CONSTANT GALE CONDITIONS OFFSHORE THE CALIFORNIA AND OREGON 
COASTS. ALTHOUGH THE GALE EVENT IS NOW OVER AND WINDS ARE 
FURTHER DECREASING...ASSOCIATED N TO NE SWELL OF AT LEAST 8 FT 
CONTINUES TO ARRIVE OVER THE FAR NORTHERN WATERS N OF 29N 
BETWEEN 122W AND 131W. THE N TO NE SWELL CONTINUES TO MIX WITH 
A NEARLY CONTINUOUS SUPPLY OF LONG PERIOD SW SWELL PROPAGATING 
OUT OF THE SOUTHERN HEMISPHERE. MODEL GUIDANCE INDICATES THAT 8 
FT NORTHERLY SWELL SHOULD DIMINISH BY THIS EVENING OR TONIGHT... 
WITH SEAS EXPECTED TO SUBSIDE FURTHER...DOWN TO 5 TO 7 FT W OF 
THE BAJA PENINSULA BY SAT.

OVER THE SOUTHERN WATERS LONG PERIOD SW SWELL PROPAGATING OUT OF 
THE SOUTHERN HEMISPHERE CONTINUES TO CROSS THE EQUATOR AND 
ENGULF MUCH OF THE TROPICAL EASTERN PACIFIC. AS A RESULT...A  
LARGE AREA OF 8 TO NEARLY 10 FT SEAS PERSISTS...GENERALLY S OF 
14N W OF 100W. IN ADDITION TO THE SWELL...A 0302 UTC QUIKSCAT 
PASS SHOWED A NARROW REGION OF ENHANCED NERLY TRADES TO 20 
KT ROUGHLY FROM 10N TO 15N W OF 130W...WHICH SUGGESTS THAT NE 
WIND WAVES ARE COMBINING WITH SW SWELL OVER THIS REGION...NOT TO 
MENTION SOME LEFTOVER SE SWELL. OVER THE NEXT FEW DAYS...NOAA 
WAVEWATCH III GUIDANCE SHOWS THIS PARTICULAR BATCH OF SW SWELL 
GREATLY SHRINKING AND SUBSIDING...WITH THE AREA OF 8 FT SEAS 
LIKELY CONFINED TO S 0F 8N BETWEEN 100W AND 126W BY FRI 
AFTERNOON AND ENTIRELY GONE BY SAT AFTERNOON. HOWEVER...NEWER 
SOUTHEASTERLY SWELL ALREADY PASSING THROUGH THE TROPICAL SOUTH 
PACIFIC IS EXPECTED TO ARRIVE OVER THE WATERS S OF 10N W OF 110W 
BY EARLY THIS WEEKEND...THOUGH WAVE HEIGHTS SHOULD STAY JUST 
BELOW 8 FT.

ELSEWHERE...A 0152 UTC QUIKSCAT PASS INDICATED THE PRESENCE OF 
AN ELONGATED AREA OF LOW PRESSURE EMBEDDED WITHIN THE ITCZ NEAR 
9N117W...MOVING SLOWLY W TO WNW AROUND THE SW PERIPHERY OF A 
LARGE MID- TO UPPER-LEVEL ANTICYCLONE CENTERED OVER NORTHERN 
MEXICO. UNLIKE 24 HOURS AGO...ASSOCIATED CONVECTION IS VIRTUALLY 
NON- EXISTENT...POSSIBLY A RESULT OF AN UNFAVORABLE CONVERGENT 
FLOW ALOFT. IN ADDITION...THE SAME QUIKSCAT PASS ALSO INDICATED 
A SECOND LESS DEFINE CYCLONIC CENTER...ALSO EMBEDDED WITHIN THE 
ITCZ...NEAR 9N111.5W...SURROUNDED BY DISORGANIZED CONVECTIVE 
ELEMENTS. ALTHOUGH CURRENT ORGANIZATION IS MINIMAL...LATEST 
CIMSS ANALYSIS REVEALS LIGHT ELY VERTICAL WIND SHEAR AND 
QUIKSCAT DATA INDICATE A LARGE AREA OF ENHANCED CROSS-EQUATORIAL 
FLOW S OF THE ITCZ BETWEEN 106W AND 120W. IF THIS WERE NOT 
ENOUGH...SATELLITE IMAGERY REVEALS A WELL-DEFINED MID-LEVEL 
CYCLONIC CIRCULATION ASSOCIATED WITH A THIRD DISTURBED WEATHER 
AREA NEAR 13N106W...MARCHING W AT 10 TO 15 KT. DEVELOPMENT OF 
ANY OF THESE AREAS IN THE SHORT-TERM DOES NOT APPEAR LIKELY 
...AND GLOBAL MODELS ECHO THIS JUDGMENT BY SUGGESTING LITTLE 
POTENTIAL FOR FORMATION. INTERESTINGLY...THE ACTIVE PHASE OF THE 
MADDEN-JULIAN OSCILLATION /MJO/ IS MOVING INTO THE WESTERN 
PACIFIC AND WILL LIKELY PROPAGATE INTO THE CENTRAL AND EASTERN 
PACIFIC WITHIN A WEEK TO TEN DAYS...LIKELY ENHANCING THE 
POTENTIAL FOR TROPICAL CYCLONE DEVELOPMENT SOON.

FINALLY...STRONG TRADES IN THE CENTRAL AND EASTERN CARIBBEAN 
SHOULD SPREAD FARTHER WEST INTO THE WESTERN CARIBBEAN BY FRI AND 
WILL CONTRIBUTE TO THE DEVELOPMENT OF A GAP WIND EVENT IN THE 
GULF OF PAPAGAYO. IN FACT...MODEL GUIDANCE SHOWS 20 KT OF NE TO 
E FLOW DOWNSTREAM OF THE GULF OF PAPAGAYO AS SOON AS 24 HRS FROM 
NOW AND INDICATE THAT WINDS SHOULD STRENGTHEN TO 20 TO 25 KT 
FROM 10N TO 12N E OF 90W WITHIN 48 HRS. ONCE WINDS BECOME 
ESTABLISHED ...EXPECT SEAS TO THEN FOLLOW SUIT BY BUILDING TO 8 
OR 9 FT BY LATE FRI OR EARLY SAT.

$$
KIMBERLAIN