000
AXPZ20 KNHC 150314
TWDEP 

TROPICAL WEATHER DISCUSSION 
NWS TPC/NATIONAL HURRICANE CENTER MIAMI FL
0405 UTC FRI MAY 15 2009

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 
0300 UTC.

...ITCZ...

THE ITCZ AXIS IS ALONG POINTS 08N77W TO 08N90W TO 11N104W TO 
04N140W. SCATTERED MODERATE ISOLATED STRONG CONVECTION IS NOTED 
WITHIN WITHIN 180 NM EITHER SIDE OF LINE 05N87W TO 12N109W TO 
08N125W.

...DISCUSSION...

ALOFT...AN UPPER TROUGH EXTENDS W ACROSS THE N PORTION OF THE 
DISCUSSION AREA FROM 33N114W THROUGH AN UPPER CYCLONE AT 32N117W 
WITH TROUGH CONTINUING SW INTO CYCLONES AT 29N122W AND 23N131W 
WITH THE TROUGH STILL CONTINUING SW TO WELL BEYOND 18N140W. AN 
UPPER ANTICYCLONE IS CENTERED AT 13N107W WITH A RIDGE EXTENDING 
NE ACROSS OLD MEXICO ALONG 20N98W WITH THE RIDGE CREST 
COLLAPSING SE OVER THE GULF OF MEXICO NEAR 25N85W. AN UPPER 
RIDGE EXTENDS W ACROSS NORTHERN VENEZUELA AND COLOMBIA TO A 
CREST OVER PANAMA. A BROAD UPPER TROUGH EXTENDS SW ACROSS THE NW 
CARIBBEAN ALONG 20N77W TO 08N86W SEPARATING THE FLOW ASSOCIATED 
WITH THE TWO ANTICYCLONES.

UPPER DIFFLUENCE IS ENHANCING CONVECTION ALONG AND N OF THE  
ITCZ TO 156N BETWEEN 98W AND 116W BUT THE DEBRIS MOISTURE SEEMS 
TO REMAIN S OF 20N. AFTERNOON CONVECTION WAS ALSO ENHANCED OVER 
INTERIOR OLD MEXICO. DEBRIS MOISTURE FROM PREVIOUS CONVECTION 
BETWEEN 115W AND 135W IS STREAMING NE WITHIN 360 NM EITHER SIDE 
OF A LINE FROM 20N106W TO 11N121W. OTHERWISE DRY UPPER AIR IS 
INDICATED NW OF LINE FROM 14N140W TO 24N106W. 
     
AT THE LOW LEVELS...A RIDGE EXTENDS SE FROM 32N134W TO 18N108W. 
THE GRADIENT NE OF THE RIDGE IS SUPPORTING N WINDS 20 TO 25 KT 
NEAR 30N120W WITH THE SEAS EXPECTED TO MAX AT ABOUT 13 FT IN THE 
N SWELL TILL MIDDAY FRI THEN THE GRADIENT SHOULD RELAX SOME FRI 
NIGHT THROUGH SAT. A SMALL AREA OF NE TRADES TO 20 KT ARE 
OBSERVED S OF THE RIDGE FROM 05N TO 15N W OF 135W...AND EXPECTED 
TO DIMINISH BELOW 20 KT BY EARLY FRI.      

GAP WINDS...N WINDS MAY INCREASE TO 20 KT IN THE GULF OF 
TEHUANTEPEC SUN MORNING.

$$
NELSON