000
AXPZ20 KNHC 182218
TWDEP 

TROPICAL WEATHER DISCUSSION  
NWS TPC/NATIONAL HURRICANE CENTER MIAMI FL
2205 UTC THU JUN 18 2009

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

BASED ON 1800 UTC SURFACE ANALYSIS AND SATELLITE IMAGERY THROUGH 
2115 UTC.

...SPECIAL FEATURE...

TROPICAL DEPRESSION ONE-E WAS ESTIMATED NEAR 18.3N 108.2W AT 2100 
UTC...OR ABOUT 215 NAUTICAL MILES SW OF MANZANILLO MEXICO...MOVING N 
AT 6 KT. FAVORABLE ANTICYCLONIC UPPER LEVEL OUTFLOW IS OVER THE 
SYSTEM...AND IS BEING ENHANCED BY AN APPROACHING UPPER LEVEL TROUGH 
TO THE NORTHWEST OF THE DEPRESSION. NUMEROUS MODERATE WITH SCATTERED 
STRONG CONVECTION WAS OVER THE CENTER AND EXTENDED OUT TO 240 NM 
OVER THE SRN SEMICIRCLE. LATEST COMPUTER MODEL GUIDANCE INDICATES A 
GENERAL NORTHWARD MOTION OVER THE NEXT 48 HOURS WITH GRADUAL 
STRENGTHENING TO STORM FORCE WINDS WITHIN 24 HOURS. THE DEPRESSION 
IS FORECAST TO BECOME A TROPICAL STORM LATE FRIDAY BEFORE MOVING 
INLAND OVER MAINLAND MEXICO FRIDAY NIGHT. SQUALLS AND HEAVY RAINS 
ASSOCIATED WITH LONG RAINBANDS WELL REMOVED FROM THE DEPRESSION HAVE 
ALREADY BEGUN TO AFFECT W COASTAL SECTIONS OF MEXICO...FROM MAZATLAN 
TO MANZANILLO...AND WILL INCREASE IN FREQUENCY AND SPREAD INLAND 
OVER THE NEXT 48 HOURS AS THE SYSTEM APPROACHES THE COAST AND MOVES 
INLAND.

...TROPICAL WAVE...

AN INVERTED TROUGH AND AN ASSOCIATED TROPICAL WAVE EXTENDED FROM THE 
ISTHMUS OF TEHUANTEPEC...SWD THROUGH THE GULF FOR A FEW DEGREES... 
AND WAS ESTIMATED TO BE MOVING W 10 TO 15 KT. CYCLONIC TURNING WA 
EVIDENT IN MID LEVEL CLOUDINESS OVER LAND JUST TO THE EAST OF THIS 
TROUGH. A LARGE AREA OF SCATTERED MODERATE TO STRONG CONVECTION WAS 
SPREAD FROM BELIZE AND THE YUCATAN PENINSULA WNW TO 100W AND S INTO 
THE OPEN PACIFIC N OF 12N. 

...ITCZ...

AXIS WAS ANALYZED ALONG 05N75W TO 05N91W TO 13N103W...AND THEN 
RESUMES FROM 08N118W TO 10N130W TO 06.5N140W. SCATTERED TO NUMEROUS 
MODERATE WITH ISOLATED STRONG CONVECTION WAS N OF 03N BETWEEN COAST 
OF COLOMBIA AND 102W. SCATTERED MODERATE ISOLATED STRONG WAS WITHIN 
120 NM N AND 60 NM S OF AXIS W OF 126W. 

...DISCUSSION...

MIDDLE AND UPPER RIDGE IS NORTH OF 20N WEST OF 125W. RIDGE IS 
FORECAST TO PERSIST AND WEAKEN SLIGHTLY THROUGH THE NEXT SEVERAL 
DAYS. THE AREA NORTH OF 25N IS MOIST IN THE MIDDLE AND UPPER LEVELS 
BUT THE ENTIRE AREA OF THE RIDGE IS CLOUD FREE IN THE MIDDLE AND 
UPPER LEVELS WITH OVERCAST TO OCCASIONALLY BROKEN STRATOCUMULUS IN 
THE LOWER LEVELS.

WELL DEFINED SHORTWAVE IS OVER THE NORTHEAST PART OF THE PACIFIC 
OCEAN AREA. THE TROUGH IS NORTH OF 22N FROM 110W TO 125W. THE AREA 
IS DRY AND CLOUD FREE IN THE MIDDLE AND UPPER LEVELS WITH MOSTLY 
OVERCAST STRATOCUMULUS IN THE LOWER LEVELS. DIFFLUENT UPPER FLOW 
EAST OF THE TROUGH COUPLED WITH SOUTHERLY FLOW IS ADVECTING A 
MOISTURE PLUME FROM THE ITCZ NORTHWARD OVER A BROAD AREA 300 NM 
EITHER SIDE OF A LINE FROM NEAR 28N100W TO 15N106W TO 05N115W. THIS 
AREA INCLUDES THE TROPICAL DEPRESSION MENTIONED ABOVE. IT ALSO 
INCLUDED ANOTHER WEAKER LOW CENTERED NEAR 11N114W 109MB. THIS LOW IS 
WEAK AND FORECAST TO REMAIN WEAK AS IT DRIFTS WEST.

REMAINDER OF THE MIDDLE AND UPPER LEVELS IS ANALYZED AS A WEAK 
HEIGHT PATTERN.

THE AREA NORTH OF THE ITCZ EAST OF THE ABOVE MENTIONED MOISTURE 
PLUME IS DIFFLUENT ALOFT WITH MULTI LEVEL CLOUDS AND EMBEDDED AREAS 
OF CONVECTION.

WEAK SURFACE RIDGE IS NORTH OF 14N WEST OF 120W. ELSEWHERE EXCEPT AS 
MENTIONED ABOVE A BROAD TROUGH IS ANALYZED ELSEWHERE AT THE SURFACE.
 
$$
STRIPLING