000
AXPZ20 KNHC 082120
TWDEP 

TROPICAL WEATHER DISCUSSION 
NWS TPC/NATIONAL HURRICANE CENTER MIAMI FL
2205 UTC THU OCT 08 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 
2100 UTC.

...TROPICAL WAVE... 

A TROPICAL WAVE WAS ANALYZED ALONG 106W FROM 09N TO 18N MOVING W 
15 KT. THIS WAVE IS MOVING PAST AN UPPER RIDGE AND IS NOW IN THE 
DIFFLUENT ALOFT REGION OF AN UPPER SHORTWAVE DISCUSSED MORE 
FULLY BELOW. THE UPPER DIFFLUENCE IS SUPPORTING CONVECTION NEAR 
THE WAVE AXIS. THE CONVECTION HAS DIMINISHED IN THE LAST SIX 
HOURS AND SHOWS LESS ORGANIZATION. THE GFS COMPUTER FORECAST 
MODEL SHOWS A BROAD SURFACE LOW PRESSURE IN THIS AREA WHICH THE 
MODEL KEEPS STATIONARY FOR THE NEXT SEVERAL DAYS. CONVECTION 
NORTH OF 15N EXTENDS ONLY TO THE EAST OF THE AXIS AND TO ABOUT 
150 NM.

...ITCZ...

THE ITCZ AXIS WAS CENTERED ALONG 08N78W TO 07N85W TO 13N105W TO 
11N130W TO 06N140W. SCATTERED MODERATE TO STRONG CONVECTION IS 
WITHIN 60 NM OF THE POINT 10.5N100.5W AND 12N106W AND 08N132W.

OTHER CONVECTION. 
SCATTERED MODERATE WITH ISOLATED STRONG CONVECTION IS WITHIN 150 
NM OF THE COAST OF MEXICO FROM 99W TO 105W.
SCATTERED MODERATE WITH ISOLATED STRONG CONVECTION IS WITHIN 60 
NM EITHER SIDE OF A LINE FROM 13N113W TO 14N128W.
  
WITHIN THE ITCZ IS A TROUGH FROM 15N126W TO 09N128W MOVING WEST 
10 KT. CONVECTION EXTENDS WITHIN ABOUT 120 NM EITHER SIDE OF THE 
TROUGH NORTH OF 13N AND IS PART OF THE CONVECTION MENTIONED 
ABOVE. THERE SEEMS TO BE NO ORGANIZATION TO THE CONVECTION. 
THE GFS COMPUTER MODEL MAINTAINS THE TROUGH AS IT MOVES WEST AND 
DOES NOT DEVELOP A CIRCULATION.

...DISCUSSION...

UPPER LEVELS...
A STRONG DEEP LAYER SHORTWAVE IS OVER THE NORTHEAST PART OF THE 
PACIFIC OCEAN AREA AND THE NORTH HALF OF THE BAJA CALIFORNIA 
PENINSULA AND THE SOUTHWESTERN UNITED STATES. THE TROUGH IS 
FORECAST TO MOVE EAST OVER NORTHERN MEXICO AND THE U.S. STATES 
OF ARIZONA AND NEW MEXICO TWO DAYS. THE AREA IS DRY AND CLOUD 
FREE. THE ONLY MOISTURE ASSOCIATED WITH THE SYSTEM IS OVER 
CALIFORNIA AND NORTHWEST HALF OF ARIZONA BUT THERE ARE NO CLOUDS 
WITH THIS SYSTEM. ASSOCIATED UPPER DIFFLUENCE IS ENHANCING 
CONVECTION WELL SOUTHEAST OF THE TROUGH OFF THE SOUTHWEST COAST 
OF CENTRAL MEXICO.

ANOTHER MOSTLY UPPER TROUGH TROUGH LOCATED WEST OF THE AREA NEAR 
150W WILL MOVE EAST AND OVER THE NORTHWEST PART OF THE AREA 
TONIGHT. THIS TROUGH WILL MOVE EAST TO WHERE THE ABOVE TROUGH IS 
SATURDAY NIGHT.

A CYCLONIC CIRCULATION IS CENTERED OVER EL SALVADOR AND IS 
MOVING WEST 15 KT. THE CIRCULATION EXTENDS OUTWARD ABOUT 250 NM. 
THE AREA IS SOMEWHAT DRY IN THE MIDDLE AND UPPER LEVELS WITH FEW 
CLOUDS OBSERVED. 

OTHERWISE A BROAD RIDGE IS OVER THE AREA.

A BROAD AREA OF MULTI LEVEL CLOUDS AND EMBEDDED AREAS OF 
CONVECTION IS NORTH OF THE ITCZ WEST OF 100W AND SOUTH OF A LINE 
FROM 12N140W TO 15N130W TO 18N110W TO WEST TEXAS. THE CONVECTION 
IS MOSTLY OVER THE OCEAN.

SURFACE...
MODERATE RIDGE IS NORTH OF THE ITCZ WEST OF 110W. ELSEWHERE 
BESIDES THE TROUGH MENTIONED WITH THE ITCZ A BROAD TROUGH IS 
ANALYZED AT THE SURFACE.

$$
LL