000
AXPZ20 KNHC 181605
TWDEP 

TROPICAL WEATHER DISCUSSION    
NWS TPC/NATIONAL HURRICANE CENTER MIAMI FL
1605 UTC FRI MAY 18 2007

TROPICAL WEATHER DISCUSSION FOR THE EASTERN PACIFIC OCEAN FROM 
THE EQUATOR TO 32N...EAST OF 140W. 

BASED ON 1200 UTC SURFACE ANALYSIS AND SATELLITE IMAGERY THROUGH 
1545 UTC.

...ITCZ...

ITCZ AXIS IS CENTERED ALONG 9N83W 9N96W 8N103W 10N126W 7N140W. 
SCATTERED MODERATE ISOLATED STRONG CONVECTION IS NOTED WITHIN 
180 NM EITHER SIDE OF LINE 7N77W 9N94W 5N105W AND ALSO LINE 
6N111W 10N123W 7N138W.

...DISCUSSION...

A SHORTWAVE TROUGH EXTENDS INTO THE DISCUSSION AREA ALONG 
32N134W 17N135W AND IS ACCOMAPNIED BY CONSIDEABLE UPPER LEVEL 
MOISTURE ON BOTH SIDES OF THE THROUGH AXIS...ROUGHLY N OF 21N W 
OF 125W. THIS TROUGH IS EXPECTED TO CONTINUE EASTWARD BUT LOSES 
SOME ITS PUSH BECOMING STATIONARY ALONG 31N116W TO 25N140W IN 48 
HOURS.

AN UPPER ANTICYCLONE CENTERED NEAR 12N109W RIDGES N ACROSS BAJA 
PENINSULA TO WELL BEYOND 32N115W. THIS ANTICYCLONE IS EXPECTED 
TO SHIFT W TO NEAR 10N112W IN 48 HOURS. UPPER DRY AIR IS 
INDICATED WITHIN 300 NM EITHER SIDE OF LINE 29N123W 33N111W. AN 
UPPER RIDGE ALSO EXTENDS W FROM THE ANTICYCLONE TO A SHARP CREST 
OVER THE DEEP TROPICS NEAR 11N126W.  ASSOCIATED UPPER DIFFLUENCE 
ENHANCES THE ITCZ BETWEEN 111W AND 129W. SOME OF THE RESULTANT 
DEBRIS MOISTURE SPREADS NE OVER THE UPPER LEVLES FROM 12N TO 22N 
BETWEEN 130W AND 112W.

AN UPPER ANTICYLONE IS ANCHORED NEAR 9N76W AND RIDGES W TO NEAR 
12N98W ENHANCING THE ITCZ E OF 100W. SOME OF THE DEBRIS MOISTURE 
IS CURRENTLY ADVECTED N A AND NE ACROSS CENTRAL AMERICA AND OVER 
THE CARIBBEAN S OF 78W. 

GULF OF TEHUANTEPEC...NLY WINDS OVER LAND ARE SUSTAINED AT 
15 TO 20 KT AND THIS MORNINGS 1144 UTC QSCAT PASS PAINTS 
NUMEROUS 30 KT NLY WINDS OVER AND JUST TO S OF OF THE GULF OF 
TEHUANTEPEC. MODELS HAVE BACKED OFF A TAD ON TYEIR PAST FEW 
RUNS...BUT STILL INDICATE MINIMAL GALE THROUGH 48 HOURS. WITH 
11Z WINDS AT 30 KT EXPECT MIMIMAL GALE BY MID MORNING THUS 
POSTED GALE CONDITIONS AGAIN. BUMPED UP FORECAST SEAS A COUPLE 
OVER FT OVER NWW3 GUIDANCE.  

$$
NELSON