000
AXPZ20 KNHC 301527
TWDEP 

TROPICAL WEATHER DISCUSSION
NWS TPC/NATIONAL HURRICANE CENTER MIAMI FL
1605 UTC WED SEP 30 2009

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 
1500. 

...SPECIAL FEATURES...
A BROAD LOW PRESSURE CENTERED ABOUT 300 NM SW OF THE BAJA 
PENINSULA NEAR 19N113W MOVING WNW NEAR 10 KT. CONDITIONS APPEAR 
TO BE FAVORABLE FOR ADDITIONAL SLOW DEVELOPMENT OF THIS SYSTEM 
DURING THE NEXT DAY OR SO OF BECOMING A TROPICAL CYCLONE. IT IS 
CURRENTLY PRODUCING STRONG WINDS MAINLY TO THE E OF THE LOW 
CENTER. SCATTERED/NUMEROUS STRONG CONVECTION IS WITHIN A 60 NM 
RADIUS OF 21N112W WITH CLUSTERS OF SCATTERED MODERATE TO STRONG 
CONVECTION COVERING THE AREA FROM 18N-24N BETWEEN 109W-115W AND 
FROM 17N-21N BETWEEN 114W-118W. 

...TROPICAL WAVE...
TROPICAL WAVE IS ALONG 101W FROM 7N-15N MOVING W NEAR 15 KT. 
WAVE IS EMBEDDED WITHIN THE ITCZ WITH ANY CONVECTION ASSOCIATED 
WITH THE ITCZ. 

...ITCZ...
ITCZ AXIS IS ALONG 8N78W 10N92W 15N110W 12N125W 13N135W 11N140W. 
ITCZ IS DISTORTED BY A 1008 MB LOW CENTERED NEAR 13N121W AND A 
1010 MB LOW CENTERED NEAR 14N135W. SCATTERED MODERATE/STRONG 
CONVECTION IS FROM 13N-15N BETWEEN 114W-120W AND FROM 9N-14N 
BETWEEN 120W-127W. SCATTERED MODERATE/ISOLATED STRONG CONVECTION 
IS WITHIN 90 NM OF THE ITCZ FROM 100W-105W AND FROM 6N-11N 
BETWEEN 102W-108W. ISOLATED CLUSTERS OF SIMILAR CONVECTION DOT 
THE AREA N OF 3N E OF 100W AND FROM 7N-16N W OF 130W. 

...DISCUSSION...
A BROAD UPPER LEVEL TROUGH COVERS THE AREA THROUGH AN UPPER LOW 
NEAR 29N131W SW TO BEYOND 23N140W WITH ABUNDANCE OF DRY STABLE 
AIR DOMINATING THE REGION N OF 20N W OF 125W. A SURFACE RIDGE 
DOMINATES MUCH OF THE SAME AREA N OF 20N W OF 120W ANCHORED BY A 
1036 MB HIGH WELL NW OF THE REGION. AN UPPER RIDGE TO THE SE OF 
THE UPPER TROUGH IS ANCHORED NEAR 20N109W AND PRODUCING STRONG 
SW UPPER LEVEL WINDS WITHIN 250 NM OF LINE FROM THE TROPICS NEAR 
20N133W TO OVER N BAJA PENINSULA AND THE DESERT SW OF THE US. 
THIS UPPER RIDGE IS ALSO PROVIDING THE LOW IN THE SPECIAL 
FEATURES FAIR OUTFLOW MAINLY TO THE N AND W OF THE SYSTEM. TO 
THE S OF THE UPPER RIDGE...A DIFFLUENT PATTERN IS ENHANCING THE 
CONVECTION ALONG THE ITCZ BETWEEN 110W-130W. AN INVERTED TROUGH 
IS OVER THE E TROPICAL PACIFIC ALONG 90W TO JUST THE E OF THE 
GULF OF TEHUANTEPEC. THE STRONG WINDS THAT HAVE BEEN IN THE GULF 
OF TEHUANTEPEC ARE FORECAST TO DIMINISH OVER THE NEXT 24 HOURS 
AS THE PRESSURE GRADIENT OVER INTERIOR OF MEXICO WEAKENS.

$$
WALLACE