000
AXPZ20 KNHC 122154
TWDEP 

TROPICAL WEATHER DISCUSSION
NWS TPC/NATIONAL HURRICANE CENTER MIAMI FL
2205 UTC FRI MAR 12 2010

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

BASED ON 1800 UTC SURFACE ANALYSIS AND SATELLITE IMAGERY THROUGH 
2030 UTC.

...ITCZ...

THE INTERTROPICAL CONVERGENCE ZONE WAS ANALYZED FROM 06N77W TO 
04N95W TO 05N110W TO 04N125W TO 04N140W. SCATTERED MODERATE WITH 
ISOLATED STRONG CONVECTION WAS WITHIN 240 NM S OF THE ITCZ AXIS 
BETWEEN 89W AND 97W. SCATTERED MODERATE CONVECTION WAS WITHIN 
120 NM N OF THE ITCZ AXIS W OF 133W AND WITHIN 90 NM S OF THE 
ITCZ AXIS BETWEEN 133W AND 137W.

...DISCUSSION...

A PROGRESSIVE PATTERN IS IN PLACE OVER N WATERS. THE WESTERLY 
UPPER JET WITH WINDS IN EXCESS OF 130 KT CENTERED ALONG 25N IS 
BEGINNING TO SHIFT MORE SOUTHWESTERLY W OF 120W AS A DEEP 
LAYERED TROUGH OVER NW FORECAST WATERS PUSHES EASTWARD. THE COLD 
FRONT ASSOCIATED WITH THIS DEEP LAYERED TROUGH IS RELATIVELY 
WEAK. THE LARGEST IMPACT FROM THIS COLD FRONT OVERNIGHT TONIGHT 
IS THE NEW SURGE OF NW SWELL PUSHING SE THROUGH THE AREA...WITH 
SIGNIFICANT WAVE HEIGHTS INCREASING TO 14 FT NW OF THE FRONT AS 
IT TRAVERSES N WATERS. THE FRONT WILL DISSIPATE AS IT MOVES INTO 
NORTHERN BAJA CALIFORNIA AND NE WATERS SAT...BUT THE PRES 
GRADIENT IS EXPECTED TO BUILD BETWEEN THE FRONTAL TROUGH AND 
HIGH PRES FOLLOWING CLOSELY BEHIND IT AS THE NORTHERN STREAM 
PATTERN BECOMES MORE AMPLIFIED. THIS WILL ALLOW FOR NW TO N 
WINDS TO INCREASE ABOVE 20 KT OVER NE WATERS OFF THE W COAST OF 
BAJA CALIFORNIA AND INTO THE NORTHERN GULF OF CALIFORNIA OVER 
THE WEEKEND.

A BROAD UPPER LEVEL ANTICYCLONIC CIRCULATION CENTERED NEAR 
07N105W HAS A RIDGE AXIS THAT EXTENDS FROM ITS CENTER NE INTO 
THE GULF OF FONSECA WHILE A SECOND RIDGE AXIS EXTENDS W OF THE 
ANTICYCLONE TO 02N128W. JUST TO THE W LIES AN UPPER LOW NEAR 
01N134W. SCATTERED MODERATE CONVECTION CAN BE FOUND NEAR THE 
ITCZ W OF 133W IN THE DIFFLUENT REGION N OF THE LOW BETWEEN IT 
AND SW FLOW ALOFT ASSOCIATED WITH THE AFOREMENTIONED JET. 
SCATTERED MODERATE WITH ISOLATED STRONG CONVECTION WAS OBSERVED 
S OF THE ITCZ BETWEEN 89W AND 97W. THIS AREA LIES IN A POOL OF 
2.25 TO 2.50 INCH PRECIPITABLE WATER VALUES AND UNDER WEAK UPPER 
LEVEL DIFFLUENCE. THIS DIFFLUENT REGION ALOFT IS EXPECTED TO 
SHIFT SW TO THE EQUATOR NEAR 100W OVER THE NEXT 24 HOURS. 
THEREFORE...LOOK FOR THE CONVECTION TO SHIFT W AND BECOME LESS 
ORGANIZED.

AT THE SURFACE...1026 MB HIGH PRES LIES OVER NW WATERS NEAR 
27N137W WITH A RIDGE AXIS EXTENDING SE TO SOCORRO ISLAND. THE 
PRES GRADIENT ALONG THE MEXICAN PACIFIC COAST NEAR 20N HAS 
STRENGTHENED BETWEEN THIS RIDGE AND TROUGHING INDUCED BY A COLD 
FRONT PASSING THROUGH EASTERN MEXICO AND THE WESTERN GULF OF 
MEXICO AS WELL AS THE INVERTED TROUGHING ON THE WESTERN SLOPES 
OF THE SIERRA MADRE OCCIDENTAL. NW TO N WINDS ARE CURRENTLY IN 
PLACE FROM 18N TO 28N W OF 115W...INCLUDING IN THE GULF OF 
CALIFORNIA. THERE ARE SEVERAL OBSERVATIONS TO CONFIRM THESE 
CONDITIONS INCLUDING THE 20 TO 25 KT WINDS SEEN IN THE 1748 UTC 
ASCAT PASS OVER THE CENTRAL GULF OF CALIFORNIA...4XFX WHICH 
REPORTED 20 KT NEAR 24N114W AT 1200 UTC...AND C6FR3 WHICH 
REPORTED 24 KT NEAR 27N115W AT 1200 UTC. THE PRES GRADIENT HERE 
WILL BREAK DOWN OVERNIGHT AS THE COLD FRONT QUICKLY PASSES SE 
THROUGH EASTERN MEXICO AND THE GULF OF MEXICO. THE WINDS ARE 
EXPECTED TO DIMINISH IN TURN.

SOUTH OF THE SURFACE RIDGE AXIS LIES A BROAD AREA OF STRONG NE 
TRADE WINDS. THE 1934 AND 1752 UTC ASCAT PASSES IN ADDITION TO 
THE 1426 UTC WINDSAT PASS SHOWED 20 TO 25 KT WINDS W OF 120W 
FROM 06N TO 20N. LITTLE CHANGE IS EXPECTED IN THE AREA AND 
STRENGTH OF THE TRADES THROUGH THE WEEKEND.

GAP WINDS...
THE COLD FRONT IN EASTERN MEXICO HAS PASSED INTO THE ISTHMUS OF 
TEHUANTEPEC AND WINDS HAVE INCREASED TO 20 KT NEAR THE COAST. 
NORTHERLY WINDS BEHIND THE COLD FRONT ARE EXPECTED TO BE SHORT 
LIVED IN THIS INCREASINGLY MORE PROGRESSIVE FLOW REGIME.  THE 
FORECAST CALLS FOR WINDS TO PEAK JUST BELOW GALE FORCE SAT 
MORNING AND QUICKLY DROP BELOW 20 KT OVERNIGHT SAT NIGHT.

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

$$
SCHAUER