000
AXPZ20 KNHC 121600
TWDEP 

TROPICAL WEATHER DISCUSSION  NWS TPC/NATIONAL HURRICANE CENTER 
MIAMI FL
1605 UTC WED APR 12 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 1200 UTC SURFACE ANALYSIS AND SATELLITE IMAGERY 
THROUGH 1545 UTC.

...ITCZ...
ITCZ AXIS ALONG 7N78W 3N100W 7N123W 3N140W. SCATTERED MODERATE 
ISOLATED STRONG WITHIN 180 NM EITHER SIDE OF AXIS E OF 86W AND 
WITHIN 150 NM OF LINE 8N130W 5N140W. ISOLATED MODERATE AND 
STRONG FROM 7N TO 12N BETWEEN 109W AND 127W. 

...DISCUSSION...
THE NE PAC IS DOMINATED BY A LONGWAVE TROUGH WITH 2 EMBEDDED 
CYCLONES ROTATING THROUGH THE PATTERN. THE SOUTHERNMOST DEEP 
LAYERED CYCLONE IS NEAR 36N130W WITH A MEAN TROUGH AXIS S ALONG 
140W TO JUST N OF THE ITCZ. A BAND OF DRY AIR IS NOTED WITHIN 
360 NM EITHER SIDE OF LINE 32N107W TO 24N124W WHERE ADDITIONAL 
DRY AIR IS SPREADING E EFFECTIVELY COVERING THE DISCUSSION AREA 
FROM 11N TO 28N W OF 128W. THIS DEEP CYCLONE IS EXPECTED TO 
CONTINUE TO MOVE SE TO NEAR 29N126W IN 36 HOURS THEN TURN NE 
INTO SOUTHERN CALIFORNIA IN 48 TO 60 HOURS. THE ASSOCIATED 
SURFACE COLD FRONT WILL SWING SE TO ALONG 130W IN 24 HOURS THEN 
OVERRUN ANY REMNANTS OF A FRONTAL TROUGH THAT CURRENTLY IS ABOUT 
360 NM E OF THIS SECONDARY BOUNDARY. THE NW SWELLS BEHIND THE 
INITIAL FRONT WILL BE REINFORCED BY LARGER N SWELLS THAT WILL 
ACCOMPANY THE SECOND FRONT.       

AN WELL DEFINED UPPER ANTICYCLONE IS CENTERED AT 14N111W WITH A 
RIDGE EXTENDING SW TO A SHARP CREST AT 4N144W. A RIDGE ALSO 
EXTENDS NE ACROSS OLD MEXICO CRESTING JUST E OF THE TX COAST AT 
28N95W. UPPER DIFFLUENCE UNDER THE RIDGE IS ENHANCING CONVECTION 
ALONG...AND JUST TO THE N OF THE ITCZ..BETWEEN 108W AND 144W.
UPPER DEBRIS MOISTURE FROM THIS CONVECTION SPREADS N ALONG THE W 
PERIPHERY OF THE RIDGE...ROUGHLY WITHIN 240 NM EITHER SIDE OF 
LINE 10N125W TO 20N115W THEN NARROWS AND CONTINUES NE ACROSS OLD 
MEXICO INTO THE GULF OF MEXICO NEAR 27N100W.

A SHARP POSITIVE TILT UPPER TROUGH LIES ACROSS THE SW ATLC ALONG
31N67W THROUGH A MOSTLY MID AND UPPER LEVEL CYCLONE NEAR 23N75W 
WITH A TROUGH CONTINUING SW THROUGH 11N94W TO A SMALL CYCLONE AT 
2N106W. DRY UPPER AIR IS INDICATED ON MOISTURE CHANNEL ROUGHLY 
WITHIN 420 NM NW OF THE TROUGH.

AN ILL-DEFINED UPPER ANTICYCLONE IS NOTED OVER VENEZUELA NEAR 
7N62W. THE ASSOCIATED RIDGE EXTENDS W ALONG 7N TO NEAR 86W 
ENHANCING SMALL CONVECTIVE BURSTS ALONG THE ITCZ E OF 87W. 
DEBRIS MOISTURE IS ADVECTED NE ACROSS CENTRAL AMERICA AND ACROSS 
THE CENTRAL CARIBBEAN.

GAP WINDS...GULF OF TEHUANTEPEC...A QSCAT PASS THIS MORNING 
AGAIN SHOWS THE DIURNAL 12Z MAX OF 30 KT. AGAIN MODEL GUIDANCE 
FLUCTUATES THE NLY WINDS FROM 15-25 KT THROUGH WED NIGHT THEN 
INCREASE N FLOW THROUGH THE GAP TO GALE FORCE AT 12 UTC THU. A 
ELY SURGE THROUGH GULF OF PAPAGAYO WILL CONTINUE THROUGH 48 
HOURS. 

$$
NELSON