000
AXPZ20 KNHC 041606
TWDEP 

TROPICAL WEATHER DISCUSSION 
NWS TPC/NATIONAL HURRICANE CENTER MIAMI FL
1605 UTC SUN JAN 04 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 
1545 UTC.

...ITCZ...

THE INTERTROPICAL CONVERGENCE ZONE WAS ALONG THE LINE...03N79W 
TO 05N100W TO 10N121W TO 06N140W. SCATTERED MODERATE FROM 09N TO 
13N BETWEEN 122W AND 130W...AND WITHIN 60 NM OF 5.5N78W. 

...DISCUSSION...

AMPLIFYING DEEP LAYERED SHORTWAVE TROUGH EXTENDS FROM A CUT-OFF
LOW NEAR 30N119W SWWD TO A BASE NEAR 19N129W. THE TROUGH IS 
SWINGING EWD AT 15-20 KT AND IS FORECAST TO TO MOVE ACROSS NRN 
MEXICO THROUGH 48 HOURS. LARGE DEEP LAYERED ANTICYCLONE WELL NW 
OF THE AREA NEAR 35N146W DOMINATES THE REGION W OF THE TROUGH 
NOTED ABOVE WITH MODERATE TO STRONG UPPER LEVEL NLY FLOW 
SWEEPING INTO THE AREA ADVECTING HIGH LEVEL MOISTURE. 

AREA OF STRONG SUBSIDENCE/DRY AIR ALOFT WAS NOTED WITHIN 240 NM 
EITHER SIDE OF A LINE FROM 20N125W THROUGH 21N140W AND WRAPPED
INTO THE SRN PERIPHERY OF THE ANTICYCLONE. AT THE SURFACE...HIGH 
PRESSURE RIDGE EXTENDS THROUGH 30N134W TO 26N125W TO 21N115W. 
MODERATE TO FR4SH TRADE WINDS WERE INDICATED S OF THE RIDGE TO 
12N AND GENERALLY W OF 125W. LAST NIGHTS QUIKSCAT DATA INDICATED 
STEADY 25 KT WINDS IN THE AREA.  

OVER THE TROPICS...WEAK ANTICYCLONIC FLOW PREVAILED E OF 115W. 
SOME UPPER DIFFLUENCE IS OCCURRING N OF THE ITCZ TO 25N AND E OF 
THE DIGGING TROUGH NOTED ABOVE. STRONG UPPER LEVEL SW WINDS WERE 
ADVECTING MULTI-LEVEL MOISTURE NORTHEASTWARD OVER SOUTHERN BAJA 
CALIFORNIA AND CENTRAL MEXICO. THE CLOUDS ARE DISSIPATING ON THE 
WINDWARD SLOPES OF THE SIERRA MADRE OCCIDENTAL.

LATEST HIGH RESOLUTION QUIKSCAT PASS INDICATED GAP WINDS OF 20 
TO 25 KT CONTINUING IN THE GULF OF PAPAGAYO REGION. THE WINDS 
ARE FORECAST TO BE INTERMITTENT WITH THE STRONGEST WINDS DURING 
THE NIGHTTIME HOURS. THE SEAS MAY REACH 8 FT DUE TO THE 
INTERMITTENT NATURE OF THE WINDS AND THE LIMITED FETCH.

NORTHERLY GAP WINDS ALSO CONTINUE IN THE GULF OF PANAMA REGION 
WITH WINDS APPROACHING 20 KT AND SEAS LESS THAN 8 FT. THESE 
WINDS ARE FORECAST TO DIMINISH TO LESS THAN 20 KT LATER TODAY.

$$
COBB