000
AXPZ20 KNHC 040918
TWDEP 

TROPICAL WEATHER DISCUSSION 
NWS TPC/NATIONAL HURRICANE CENTER MIAMI FL
1005 UTC SUN JAN 04 2009

TROPICAL WEATHER DISCUSSION FOR THE EASTERN PACIFIC OCEAN
FROM THE EQUATOR TO 32N...EAST OF 140W. 

BASED ON 0600 UTC SURFACE ANALYSIS AND SATELLITE IMAGERY THROUGH 
0900 UTC.

...ITCZ...

THE INTERTROPICAL CONVERGENCE ZONE WAS ALONG THE LINE...04N77W 
TO 06N105W TO 08N120W TO 08N140W. THERE IS NO SIGNIFICANT 
CONVECTION ALONG THE ITCZ.

...DISCUSSION...

STRONG DEEP LAYER SHORTWAVE IS MOVING OVER THE NORTHEAST PART OF 
THE PACIFIC OCEAN REGION AND NORTHWESTERN MEXICO. THE FEATURE IS 
FORECAST TO MOVE A LITTLE EAST THROUGH 48 HOURS AND BE OVER 
NORTHWESTERN AND NORTHERN MEXICO.  MULTI LEVEL CLOUDINESS IS 
MOSTLY EAST OF THE TROUGH AXIS WHICH IS ALONG 121W. THE 
CLOUDINESS IS MOVING OVER NORTHWESTERN MEXICO AND IS ALSO 
ADVECTING OVER ARIZONA AND NEW MEXICO IN THE SOUTHWESTERN UNITED 
STATES. 

A MORE EXTENSIVE MAINLY UPPER TROUGH IS ALSO OVER THE NORTHERN 
PART OF THE AREA NORTH OF A LINE FROM THE TEXAS BIG BEND REGION 
NEAR 30N102W TO 18N125W TO 16N140W. NORTH OF THIS LINE...EXCEPT 
FOR THE SHORTWAVE MENTIONED ABOVE...THE AREA IS DRY AND CLOUD 
FREE IN THE MIDDLE AND UPPER LEVELS. THE LOWER LEVELS NORTH OF 
THIS LINE TO 21N ARE COVERED IN OVERCAST STRATOCUMULUS WITH 
BROKEN STRATOCUMULUS NORTH OF 21N. 

REMAINDER OF THE MIDDLE AND UPPER LEVELS IS UNDER WEAK 
ANTICYCLONIC FLOW. SOME UPPER DIFFLUENCE IS OCCURRING NORTH OF 
THE ITCZ TO 17N FROM 113W TO 123W. ASSOCIATED MULTI LEVEL 
MOISTURE AND CLOUDS ARE ADVECTING NORTHEASTWARD OVER SOUTHERN 
BAJA CALIFORNIA AND CENTRAL MEXICO. THE CLOUDS ARE DISSIPATING 
ON THE WINDWARD SLOPES OF THE SIERRA MADRE OCCIDENTAL. THE AREA 
EAST OF A LINE FROM NEAR 24N98W TO 16.5N110W TO 07N115W TO 
05N140W IS DRY AND CLOUD FREE EXCEPT FOR OVERCAST STRATOCUMULUS 
IN THE LOWER LEVELS SOUTH OF THE ITCZ EAST OF 120W.

MODERATE SURFACE RIDGE IS NORTH OF 15N WEST OF 115W. ELSEWHERE A 
BROAD TROUGH IS ANALYZED AT THE SURFACE. THE RIDGE IS FORECAST 
TO STRENGTHEN SLIGHTLY IN THE NEXT 48 HOURS.

GAP WINDS OF 20 TO 25 KT CONTINUE IN THE GULF OF PAPAGAYO 
REGION. THE WINDS ARE FORECAST TO BE INTERMITTENT WITH THE 
STRONGEST WINDS DURING THE NIGHTTIME HOURS. THE SEAS ARE 
EXPECTED TO REMAIN LESS THAN 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 TODAY.

$$
LL