000
AXPZ20 KNHC 130349
TWDEP 

TROPICAL WEATHER DISCUSSION   
NWS TPC/NATIONAL HURRICANE CENTER MIAMI FL
0405 UTC WED JAN 13 2010

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

BASED ON 0000 UTC SURFACE ANALYSIS AND SATELLITE IMAGERY THROUGH 
0300 UTC.

...ITCZ...
AXIS ANALYZED ALONG 02N78W TO 05N105W TO 04N117W TO 06N128W TO 
07N140W. SCATTERED MODERATE AND ISOLATED STRONG CONVECTION WAS 
NOTED WITHIN 300 NM N OF THE AXIS BETWEEN 101W AND 104W AND 
WITHIN 120 NM N OF THE AXIS BETWEEN 104W AND 110W. SCATTERED 
MODERATE CONVECTION WAS NOTED WITHIN 60 NM N OF THE AXIS BETWEEN 
117W AND 122W. SCATTERED MODERATE AND ISOLATED STRONG CONVECTION 
WAS NOTED WITHIN 90 NM N OF THE AXIS W OF 138W.

...DISCUSSION...
AN EXPANSIVE UPPER LEVEL RIDGE EXTENDS FROM AN UPPER ANTICYCLONE 
CENTERED NEAR 15N145W TO 20N130W TO 30N116W. WATER VAPOR 
SATELLITE IMAGERY INDICATES A VERY DRY AND STABLE AIR MASS 
ACROSS THE AREA N OF 10N W OF 115W. UPPER LEVEL DIFFLUENT FLOW 
BETWEEN THE RIDGE AND AN UPPER LEVEL CYCLONIC CIRCULATION W OF 
THE DISCUSSION AREA IS ENHANCING CONVECTION ALONG THE ITCZ W OF
138W. A WEAK UPPER LEVEL TROUGH IS SKIRTING THE FAR N PORTION OF 
THE AREA EXTENDING FROM NEAR 29N131W TO 35N121W. ANOTHER UPPER 
LEVEL TROUGH EXTENDS FROM THE ITCZ NEAR 08N124W TO 15N110W TO 
NEAR PUERTO VALLARTA MEXICO TO AN UPPER LEVEL CYCLONE CENTERED 
NEAR THE BIG BEND OF TEXAS. A 95 TO 105 KT JETSTREAM IS SE OF 
THE TROUGH AXIS ADVECTING ABUNDANT TROPICAL MOISTURE FROM THE 
ITCZ TO THE NE ACROSS CENTRAL MEXICO AND INTO THE WESTERN GULF 
OF MEXICO AND BAY OF CAMPECHE. AN UPPER LEVEL ANTICYCLONIC 
CIRCULATION IS CENTERED NEAR 05N83W WITH A RIDGE AXIS EXTENDING 
ACROSS CENTRAL AMERICA TO THE YUCATAN PENINSULA.

AT THE SURFACE...A DISSIPATING COLD FRONT EXTENDS FROM 30N133W 
TO 26N140W...ASSOCIATED WITH THE AFOREMENTIONED WEAK UPPER 
LEVEL TROUGH. A 1021 MB SURFACE HIGH IS CENTERED E OF THE FRONT 
NEAR 27N131W. A RIDGE EXTENDS FROM THE HIGH TO NEAR 21N140W. 
FLOW AROUND THE SOUTHERN PORTION OF THIS RIDGE IS PRODUCING 20 
TO 25 KT TRADES FROM 07N TO 15N W OF 121W. A COUPLE OF SURFACE 
TROUGHS ARE EMBEDDED WITHIN THE ITCZ...ONE EXTENDING FROM 
09N106W TO 03N107W AND ANOTHER TO THE W EXTENDING FROM 09N117W 
TO 03N118W. 

A FRONTAL TROUGH EXTENDS ACROSS WESTERN PANAMA FROM THE 
CARIBBEAN SEA TO 05N88W. ANY SIGNIFICANT CONVECTION PREVIOUSLY 
ASSOCIATED WITH THIS FEATURE HAS DISSIPATED.

...GAP WINDS...
GULF OF TEHUANTEPEC...A TIGHT PRES GRADIENT ALONG THE SE COAST 
OF MEXICO CONTINUES TO PRODUCE MINIMAL GALE FORCE WINDS. THE 
GRADIENT WILL WEAKEN ON WED AND WINDS WILL DIMINISH TO LESS THAN 
GALE FORCE WITHIN 30 HOURS.

GULF OF PAPAGAYO...MODERATE TO STRONG GALE FORCE WINDS PERSIST 
IN THE GULF OF PAPAGAYO AND DOWNWIND TO 09N89W. WINDS WILL 
GRADUALLY DIMINISH TO LESS THAN GALE FORCE WITHIN THE NEXT 30 
HOURS.

GULF OF PANAMA...20 KT NORTHERLY WINDS ARE BLOWING S FROM THE SW 
CARIBBEAN SEA ACROSS THE ISTHMUS OF PANAMA AND DOWNWIND OVER THE 
GULF OF PANAMA TO 03N BETWEEN 79W AND 82W. THESE WINDS ARE 
EXPECTED TO CONTINUE DURING THE NEXT 48 HOURS AS A TIGHT PRES 
GRADIENT REMAINS IN PLACE DUE TO LOW PRES OVER NE COLOMBIA.

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

$$
LEWITSKY