000
AXPZ20 KNHC 150944
TWDEP 

TROPICAL WEATHER DISCUSSION   
NWS TPC/NATIONAL HURRICANE CENTER MIAMI FL
1005 UTC FRI JAN 15 2010

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 
0930 UTC.

...ITCZ...
AXIS IS ANALYZED ALONG 02N78W TO 08N90W TO 04N105W TO 06N115W TO 
03N130W TO 06N140W. SCATTERED MODERATE ISOLATED STRONG WITHIN 
60-90 NM EITHER SIDE OF AXIS BETWEEN 104W AND 117W. SCATTERED 
MODERATE WITHIN 60 NM S OF AXIS BETWEEN 95W AND 98W.

...DISCUSSION...
AMPLIFIED PATTERN IN PLACE ACROSS THE AREA WITH A SHARP DEEP 
LAYERED TROUGH JUST W OF THE DISCUSSION AREA WITH AXIS ALONG 
32N142W TO JUST E OF THE HAWAIIAN ISLANDS. A BROAD MID TO UPPER 
LEVEL ANTICYCLONIC CIRCULATION IS CENTERED NEAR 15N133W. A RIDGE 
AXIS EXTENDS FROM THE CIRCULATION TO 32N125W. STRONG SUBSIDENCE 
WITH A VERY DRY AND STABLE AIR MASS IS N OF THE ITCZ TO 24N W OF 
100W...THE ONLY EXCEPTION IS A SWATH OF MID TO HIGH LEVEL CLOUDS 
MOVING THROUGH THE FAR NW CORNER OF THE DISCUSSION AREA AHEAD OF 
THE APPROACHING UPPER LEVEL TROUGH NOTED ABOVE. 

FURTHER DOWNSTREAM AN UPPER LEVEL TROUGH AXIS EXTENDS FROM A 
CYCLONIC CIRCULATION OVER N CENTRAL MEXICO TO NEAR 10N110W. AN 
ANTICYCLONIC CIRCULATION IS OVER NORTHERN COLOMBIA WITH A RIDGE 
EXTENDING W ACROSS PANAMA TO 04N88W. A 110-160 KT NORTHERLY 
JETSTREAM EXTENDS FROM NW MEXICO JUST E OF THE GULF OF 
CALIFORNIA NEAR 30N110W TO 21N104W.

AT THE SURFACE...1024 MB HIGH PRES IS CENTERED NEAR 31N125W WITH 
A RIDGE COVERING THE AREA N OF 15N W OF 108W. A TIGHT PRES 
GRADIENT INDUCED BY THE RIDGE IS PRODUCING MODERATE TO FRESH NE 
TO E TRADES ALONG THE SOUTHERN PERIPHERY. A COLD FRONT IS JUST 
ENTERING THE FAR NW CORNER OF THE DISCUSSION AREA WITH SOUTHERLY 
WINDS INCREASING TO 20-30 KT NW OF A LINE FROM 30N132W TO 
25N140W. 

A TIGHT PRES GRADIENT ALSO REMAINS IN PLACE OVER THE GULF OF 
CALIFORNIA DUE TO THE HIGH W OF THE BAJA PENINSULA AND 
TROUGHINESS OVER MAINLAND MEXICO. AS A RESULT STRONG NORTHERLY 
WINDS ARE OCCURRING IN THE GULF OF CALIFORNIA N OF 24N. THE 
LOCAL DIAGNOSTIC TOOL SUGGESTS WINDS HAVE DROPPED BELOW GALE 
FORCE. WINDS WILL DIMINISH TO 20 KT LATER TODAY AND LESS THAN 20 
KT BY EARLY SAT. 

A COUPLE OF VERY WEAK SURFACE TROUGHS ARE EMBEDDED IN THE ITCZ. 
THE EASTERN MOST TROUGH EXTENDS FROM 10N119W TO 04N121W. 
ISOLATED SHOWERS ARE CONFINED TO THE MIDDLE PORTION OF THE 
TROUGH FROM 04N TO 06N. THE OTHER TROUGH EXTENDS FROM 10N138W TO 
04N140W...AND IS IN THE PROCESS OF MOVING W OF THE AREA.  

...GAP WINDS...
GULF OF PANAMA...A 0254 UTC ASCAT PASS INDICATED NORTHERLY WINDS 
HAVE DROPPED BELOW 20 KT IN THE GULF OF PANAMA. A SHIP WITH CALL 
SIGN A8IP4 REPORTED N WINDS OF 18 KT AT 0900 UTC.

GULF OF PAPAGAYO...THE SAME ASCAT PASS NOTED ABOVE INDICATED 
NE-E WINDS OF 20 TO 25 KT IN THE GULF OF PAPAGAYO AND DOWNSTREAM 
TO 90W. A SHIP WITH CALL-SIGN WRFJ REPORTED 25 KT WITHIN THIS 
SWATH OF WINDS AT 05 UTC. THESE WINDS WILL GRADUALLY DIMINISH TO 
NEAR 20 KT ON FRI...THEN WILL PULSE UP AND DOWN THEREAFTER TO 
ABOVE/BELOW 20 KT DUE PRIMARILY TO DIURNALLY DRIVEN DRAINAGE 
FLOW.

GULF OF TEHUANTEPEC...HIGH PRES WILL BUILD DOWN ALONG THE SW 
GULF OF MEXICO COAST AND WESTERN BAY OF CAMPECHE ON SAT...AND 
NORTHERLY WINDS WILL INCREASE IN THE GULF OF TEHUANTEPEC TO 20 
KT SAT EVENING...AND TO 30 KT OVERNIGHT SAT NIGHT. 

FOR ADDITIONAL INFORMATION PLEASE VISIT 
HTTP://WWW.HURRICANES.GOV/MARINE

$$
COBB