000
AXPZ20 KNHC 210822 RRA
TWDEP 

TROPICAL WEATHER DISCUSSION 
NWS TPC/NATIONAL HURRICANE CENTER MIAMI FL
1005 UTC SUN DEC 21 2008

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 
0800 UTC.

...ITCZ...

ITCZ AXIS IS CENTERED ALONG 04N77W TO 06N85W TO 10N118W TO 
10N132W TO 10N130W TO 07N140W. SCATTERED MODERATE WITHIN 75 NM  
BETWEEN 132W AND 136W. 

...DISCUSSION...

A STABLE UPPER LEVEL CYCLONIC CIRCULATION IS CENTERED 
20N134W...WITH AN ASSOCIATED SURFACE TROUGH 18N130W TO 07N133W. 
1030 MB HIGH PRES REMAINS IN PLACE TO THE NORTH NEAR 32N130W. 
SHIP OBSERVATIONS AND QUIKSCAT DATA SHOW 20 TO 30 KT WINDS IN 
THE TIGHT PRESSURE GRADIENT AREA BETWEEN THE TROUGH AND THE HIGH 
PRES. FRESH NORTHERLY WINDS EXTEND AS FAR EAST AS THE GULF OF 
CALIFORNIA ON THE EAST SIDE OF THE SURFACE HIGH PRES. AMPLE 
MOISTURE AND DIVERGENT FLOW ALOFT ON THE SE SIDE OF THE UPPER 
LOW IS AIDING IN SCATTERED MODERATE CONVECTION ALONG THE SURFACE 
TROUGH. UPPER CYCLONIC CIRCULATION IS RETROGRADING SLOWLY TO THE 
WSW...TO A POSITION SOUTH OF AN UPPER RIDGE N OF HAWAII. THIS 
WILL SET UP A REX BLOCK PATTERN FROM THE EARLY TO MIDDLE PART OF 
NEXT WEEK. THE PATTERN BECOMES MORE AMPLIFIED AS SHORT WAVE 
ENERGY DIGS ON THE EAST SIDE OF THE UPPER RIDGE...THROUGH THE 
PACIFIC NORTHWEST AND INTO SOUTHERN CALIFORNIA BY MIDWEEK. THIS 
FORMS A LONG WAVE TROUGH OVER THE WESTERN U.S. AND FAR EASTERN 
PACIFIC...AND ALLOWS THE REX BLOCK COMPLEX TO BUILD SLIGHTLY 
WESTWARD. NET EFFECT IS PUSH THE BAND OF STRONG WINDS FURTHER 
WEST TOWARD HAWAII THROUGH EARLY NEXT WEEK. MEANWHILE ANOTHER 
ROUND OF SHORT WAVE ENERGY ROUNDS THE EAST SIDE OF THE RIDGE AND 
DIGS INTO THE BASE OF THE LONG WAVE TROUGH OVER SOUTHERN 
CALIFORNIA TUE INTO WED. THIS BRINGS STRONGER NLY WINDS TO THE 
NORTHERN BAJA COAST BY EARLY TUE. 

HIGH PRES BUILDING BEHIND A COLD FRONT EMERGING ACROSS THE THE 
GULF OF MEXICO WILL INDUCE WINDS TO INCREASE TO 20 KT BRIEFLY 
OVER THE GULF OF TEHUANTEPEC MON THROUGH TUE. THE PATTERN IS 
FAIRLY PROGRESSIVE AND THE HIGH PRES WILL BUILD RAPIDLY EASTWARD 
WITH A MINOR SOUTHERN COMPONENT SO DO NOT EXPECT VERY STRONG 
WINDS INTO THE TEHUANTEPEC AREA. FURTHER SOUTH...FRESH WINDS 
SPORADICALLY PERSIST THROUGH THE GULF OF PAPAGAYO THROUGH EARLY 
NEXT WEEK...MAINLY DUE TO FRESH TRADES OVER THE CARIBBEAN. SAME 
IS TROUGH THROUGH THE ISTHMUS OF PANAMA...WHERE SHIP 
OBSERVATIONS BOLSTER REPORTS FROM AN EARLIER QUIKSCAT PASS 
SHOWING 20 KT WINDS INTO THE GULF OF PANAMA. THIS WILL DIMINISH 
LATER TODAY AS TRADES DIMINISH N OF THE AREA.

$$
CHRISTENSEN