000
AXPZ20 KNHC 210930
TWDEP 

TROPICAL WEATHER DISCUSSION   
NWS TPC/NATIONAL HURRICANE CENTER MIAMI FL
1005 UTC FRI APR 21 2006

TROPICAL WEATHER DISCUSSION FOR THE EASTERN PACIFIC OCEAN FROM 
THE EQUATOR TO 32N...EAST OF 140W. THE FOLLOWING INFORMATION IS 
BASED ON SATELLITE IMAGERY...WEATHER OBSERVATIONS...RADAR...AND 
METEOROLOGICAL ANALYSIS.

BASED ON 0600 UTC SURFACE ANALYSIS AND SATELLITE IMAGERY THROUGH 
0845 UTC.

...ITCZ...
ITCZ AXIS IS CENTERED ALONG 8N78W 8N90W 8N100W 7N110W 6N120W 
5N130W 4N140W. SCATTERED MODERATE CONVECTION IS WITHIN 60 NM 
EITHER SIDE OF THE AXIS BETWEEN 133W-136W. WIDELY SCATTERED
MODERATE CONVECTION IS WITHIN 60 NM EITHER SIDE OF THE AXIS
BETWEEN 113W-116W AND WEST OF 137W. ISOLATED STRONG CONVECTION
IS WITHIN 30 NM OF 7N78.5W. ISOLATED MODERATE CONVECTION IS 
NOTED FROM 4N-6N BETWEEN 124W-128W.

...DISCUSSION...
PROGRESSIVE PATTERN IS OBSERVED ACROSS THE DISCUSSION AREA NORTH 
OF 16N AS A RATHER SHARP MID/UPPER TROUGH WITH AXIS THROUGH 
32N128W 24N129W TO 20N135W IS PRESENTLY QUICKLY MOVING EASTWARD 
OVER THE WESTERN PORTION. TO ITS EAST...MID/UPPER LEVEL RIDGING 
NORTH OF 22N IS RETREATING EASTWARD OVER BAJA CALIFORNIA AND THE 
SOUTHWEST UNITED STATES AS THE TROUGH PUSHES EAST. A MID/UPPER 
LEVEL VORTEX EMBEDDED IN THE TROUGH IS NOTED ON WATER VAPOR 
IMAGERY TO BE NEAR 30N128W AND MOVING EAST ABOUT 25-30 KT. THE 
CORRESPONDING SURFACE COLD FRONT ENTERS THE AREA THROUGH 32N135W 
BUT WEAKENS TO A SHEAR LINE AT 30N137W AND CONTINUES SOUTHWEST 
TO BEYOND THE AREA AT 28N140W. THERE CONTINUES TO BE LIMITED 
UPPER LEVEL DYNAMICS/LIFT WITH THE FRONT SO ONLY BROKEN TO 
SCATTERED LOW CLOUDS WITH WIDELY SCATTERED SHOWERS ARE OCCURRING 
ALONG THE BOUNDARY WITH NO SIGNIFICANT PRECIPITATION EXPECTED 
WITH THE BOUNDARY AS IT WEAKENS THROUGH THE NEXT 18-24 HOURS.
THE MAIN PROBLEM WITH THIS BOUNDARY IS RELATED TO THE MARINE
ASPECT OF THE AFFECTED AREA AS LARGE SWELLS...POSSIBLY UP TO
12 FT...WILL PROPAGATE EASTWARD OVER THE NORTHERN PORTION OF THE
AREA REACHING TO NEAR 130W ON SATURDAY BEFORE SUBSIDING AS
THE BOUNDARY DISSIPATES. A VERY PRONOUNCED JET STREAM BRANCH
WITH MAXIMUM WINDS OF 70-110 KT ENTERS THE AREA THROUGH 18N140W 
AND CONTINUES NORTHEAST TO 18N130W...AND FURTHER NORTHEASTWARD
TO ACROSS NORTHERN BAJA AND SOUTHERN CALIFORNIA.

ELSEWHERE AT THE SURFACE OVER THE WESTERN PORTION THE 
SUBTROPICAL RIDGE EXTENDS SOUTHEASTWARD INTO THE AREA THROUGH 
32N135W AND THROUGH 25N125W TO 21N118W. HIGH PRESSURE COVERS THE 
AREA NORTH OF 17N WEST OF 116W. RIDGE WILL ONLY WEAKEN SLIGHTLY 
THROUGH THE NEXT 18 HOURS BEFORE RE-STRENGTHENING AS HIGH 
PRESSURE REBUILDS INTO THE AREA BEHIND THE AFOREMENTIONED COLD 
FRONT OVER THE WEEKEND.

FURTHER E...MID/UPPER LEVEL TROUGH EXTENDS SOUTHWEST INTO THE 
EASTERN PACIFIC FROM PUERTO VALLARTA MEXICO SOUTHWEST TO 
11N111W. CONFLUENT FLOW PATTERN N OF 14N EAST OF 110W IS 
RESULTING IN MODERATE TO STRONG SUBSIDENCE AND DRY STABLE 
CONDITIONS OVER THIS AREA WITH VERY MINIMAL SHOWER/THUNDERSTORM 
ACTIVITY NOTED. A PERSISTENT 90 NM WIDE LINE OF SCATTERED TO 
BROKEN LOW CLOUDS WITH ISOLATED SHOWERS EXTENDS FROM 14N98W 
ALONG 12N102W TO 11N107W. BROAD MID/UPPER LEVEL RIDGING COVERS 
THE AREA NORTH OF 5N AND EAST OF 110W TO ACROSS MEXICO AND 
CENTRAL AMERICA. AN ASSOCIATED ANTICYCLONIC CIRCULATION CENTER 
IS SEEN NEAR 8N98W. ISOLATED STRONG CONVECTION HAS DEVELOPED 
NEAR THE COAST OF SOUTHERN PANAMA AT 7N79W.

$$
AGUIRRE