000
AXPZ20 KNHC 050957
TWDEP 

TROPICAL WEATHER DISCUSSION    
NWS TPC/NATIONAL HURRICANE CENTER MIAMI FL
1005 UTC THU FEB 05 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 
0945 UTC.

...ITCZ...

ITCZ AXIS FLUCTUATES BETWEEN 02.5N AND 04.5N FROM COLOMBIA TO 
140W. ISOLATED MODERATE CONVECTION IS FLARING WITHIN 120 NM OF 
THE AXIS TO THE E OF 94W.

...DISCUSSION...

A QUASI STATIONARY UPPER ANTICYCLONE IS CENTERED OVER THE DEEP 
TROPICS NEAR 10N104W WITH ITS ASSOCIATED RIDGE EXTENDING E TO W 
ALONG 11N BETWEEN 92W AND 113W. A RIDGE ALSO EXTENDS N CRESTING 
OVER ARIZONA AT 32N110W. AN UPPER TROUGH EXTENDS OVER THE FAR SE 
PORTION FROM 12N78W TO 01N93W...AND IS MOVING W WITH TIME. UPPER 
DEBRIS MOISTURE FROM THE ISOLATED CONVECTION DESCRIBED IN THE 
ITCZ SECTION...IS NOTED FROM 11N TO 03N BETWEEN 88W AND 78W. 
THE EASTERN CONUS IS DOMINATED BY A LONG WAVE TROUGH THAT HAS 
DUG S TO BASE ALONG 18N BETWEEN 80W AND 95W...AND IS ACCOMPANIED 
BY VERY DRY UPPER AIR THAT MERGES WITH DRY UPPER AIR ASSOCIATED 
WITH THE TROPICAL RIDGE...RESULTING IN VERY DRY UPPER AIR OVER 
THE ENTIRE AREA SE OF LINE 25N97W TO 10N130W.

A DEEP LAYERED CYCLONE IS N OF THE AREA NEAR 36N131W WITH AN 
UPPER TROUGH EXTENDING S TO 15N126W. A BAND OF DRY UPPER AIR IS 
NOTED WITHIN 90 NM EITHER SIDE OF LINE FROM 31N110W TO 24N124W 
TO 22N140W...AND ALSO N OF 27N BETWEEN 125W AND 140W. A BAND OF 
UPPER MOISTURE IS NOTED WITHIN 150 NM EITHER SIDE OF LINE FROM 
14N140W TO 20N120W TO OVER OLD MEXICO AT 26N104W WHERE THE 
MOISTURE EVAPORATES IN THE DRY AIR PREVIOUSLY MENTIONED.

AT THE LOW LEVELS...WEAK RIDGING CONTINUES OVER THE AREA N OF 
20N E OF 123W. A COLD FRONT IS FALLING APART FROM 32N122W TO 
20N140W. THE CYCLONE MENTIONED ABOVE WILL DRIVE A SERIES OF COLD 
FRONTS ACROSS THE NORTHERN PORTION OF THE DISCUSSION AREA THIS 
WEEKEND. A RIDGE WILL BUILD SE FROM 30N140W TO 15N110W AND BLOCK 
THE SOUTHERN ADVANCE OF THE FRONT. SURFACE WINDS SW OF THE RIDGE 
WILL INCREASE TO 20 TO 25 KT BY SAT AS LARGE NW SWELLS PROPAGATE 
SE ACROSS MOST OF THE AREA...EVENTUALLY MERGING WITH NE SWELLS 
FROM THE CENTRAL AMERICAN GAP WIND EVENTS DESCRIBED NEXT.     

CENTRAL AMERICAN GAPS...
GULF OF TEHUANTEPEC...STORM FORCE WINDS TO 55 KT ARE EXPECTED TO 
PERSIST THROUGH EARLY FRI NIGHT...THEN GALE STRENGTH THROUGH MID 
DAY SAT. GALE WINDS OVER THE WATERS BETWEEN 85W AND 94W WILL 
DIMINISH TO LESS THAN GALE FORCE MID DAY FRI. NE WINDS AT 20 TO 
30 KT OVER THE PACIFIC COASTAL WATERS OF COSTA RICA AND PANAMA 
WILL DIMINISH BELOW 20 KT LATE SUN. ASSOCIATED N SWELLS 8 TO 11 
FT WILL SPREAD S CROSSING THE EQUATOR BETWEEN 90W AND 105W EARLY 
FRI...WITH THE AREA EXPANDING FROM 85W TO 115W SAT. THE 
ASSOCIATED NE SWELLS WILL BEGIN TO MERGE WITH THE NW COMPONENT 
DESCRIBED ABOVE IN THE VICINITY OF 13N110W LATE FRI NIGHT.       

$$
NELSON