000
AXPZ20 KNHC 050328
TWDEP 

TROPICAL WEATHER DISCUSSION    
NWS TPC/NATIONAL HURRICANE CENTER MIAMI FL
0405 UTC SAT MAY 05 2007

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 0000 UTC SURFACE ANALYSIS AND SATELLITE IMAGERY THROUGH 
0315 UTC.

...ITCZ...
AXIS ALONG 7N78W 10N94W 7N110W 9N120W 3N140W. SCATTERED MODERATE 
TO STRONG WITHIN 120-180 NM EITHER SIDE OF AXIS BETWEEN 110W AND 
117W...AND WITHIN 60 NM EITHER SIDE OF LINE 12.5N105W 11N110W. 
SCATTERED MODERATE WITHIN 90 NM EITHER SIDE OF AXIS BETWEEN 92W 
AND 101W. 

...DISCUSSION...
N OF 20N...HIGHLY AMPLIFIED PATTERN IN PLACE WITH REX BLOCK 
FEATURE JUST NW OF DISCUSSION AREA BETWEEN 140W AND 145W 
CONSISTING OF A DRY MID/UPPER LOW CYCLONIC CIRCULATION NEAR 
26N146W...AND UPPER RIDGE TO THE N AND NE. ASSOCIATED 1029 MB 
SFC HIGH IS CENTERED NEAR 34N143W. MOST RECENT SHIP OBSERVATIONS 
SHOW A CONTINUATION OF FRESH TO STRONG TRADES ON THE SOUTHERN 
PERIPHERY OF THE HIGH AS FAR S AS 8N. TO THE EAST OF THE UPPER 
RIDGE...A BROAD MID TO UPPER LEVEL TROUGH DIGGING INTO THE 
NORTHERN ROCKIES IS PROVIDING UPPER SUPPORT TO A 1000 MB SURFACE 
LOW PRESSURE SYSTEM OVER CALIFORNIA AND ASSOCIATED COLD FRONT 
MOVING FROM THE SOUTHERN CALIFORNIA COAST INTO THE DISCUSSION 
AREA ALONG 31N. THE TIGHT GRADIENT BETWEEN THE SURFACE HIGH PRES 
TO THE W AND THE LOW OVER CALIFORNIA HAS SET UP A GOOD NW FETCH
OF GALE FORCE WINDS WITH LARGE NLY SWELLS OF UP TO 13 FT NOW 
MOVING INTO THE NE PART OF THE AREA. 

FRESH TO STRONG NWLY WINDS OF 20-25 KT ARE EXTENDING SWD ALONG 
THE BAJA COAST ON THE EASTERN EDGE OF THE HIGH PRES. LITTLE 
CHANGE IS EXPECTED IN CONDITIONS THROUGH SAT AS THE RIDGE 
REMAINS IN PLACE. HOWEVER...THE UPPER RIDGE WILL WEAKEN BY LATE 
SAT...AHEAD OF A DEEP UPPER TROUGH ADVANCING THROUGH THE CENTRAL 
PACIFIC...ALLOWING THE SURFACE RIDGE TO WEAKEN SLIGHTLY. THE NW 
FLOW OFF OF BAJA WILL SUBSEQUENTLY DIMINISH WITHIN 36 HOURS 
...AS WILL TRADE FLOW S OF THE RIDGE.

S OF 20N...UPPER TROUGH EXTENDS FROM THE SW N ATLANTIC SOUTHWEST 
THROUGH THE CENTRAL BAHAMAS...W CARIBBEAN TO THE EAST PACIFIC 
NEAR 10N88W. FAIRLY DRY MID LEVEL AIR ASSOCIATED WITH THE UPPER 
TROUGH IS SUPPRESSING CONVECTION OVER THE EAST PACIFIC. 
HOWEVER...UPPER DIVERGENCE E OF THE UPPER TROUGH IS ENHANCING 
CONVECTION OFF THE COLOMBIAN COAST AND GULF OF PANAMA. FURTHER 
W...UPPER LEVEL ANTICYCLONE CENTERED NEAR 11N120W IS SIMILARLY 
AIDING CONVECTION ALONG AND N OF THE ITCZ BETWEEN 110W AND 117W.

$$
COBB