000
AXPZ20 KNHC 160350
TWDEP 

TROPICAL WEATHER DISCUSSION    
NWS TPC/NATIONAL HURRICANE CENTER MIAMI FL
0405 UTC MON MAR 16 2009

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...

THE ITCZ AXIS EXTENDS FROM 09N83W TO 04N91W TO 05N96W...AND FROM 
05N121W TO 06N131W TO 04N140W. NO SIGNIFICANT CONVECTION CAN BE 
FOUND NEAR THE ITCZ AXIS.

...DISCUSSION...

THE PATTERN OVER WATERS N OF 20N IS RELATIVELY AMPLIFIED YET 
PROGRESSIVE WITH A TROUGH PASSING EASTWARD INTO NW MEXICO AND A 
DEEP LAYER LOW CENTERED A FEW DEGREES NORTH OF THE HAWAII 
ISLANDS...WITH RIDGING BETWEEN THESE TWO FEATURES.  THE 
STRONGEST SHORTWAVE ENERGY ASSOCIATED WITH THE MEXICAN TROUGH IS 
CURRENTLY PASSING THROUGH THE SOUTHERN GULF OF CALIFORNIA AND 
INTO THE ADJACENT W COAST OF MEXICO...AND SHOULD LIFT NE AND 
INTO THE LEADING EDGE OF THE BROADER TROUGH MOVING INTO THE 
CENTRAL U.S. OVER THE NEXT DAY OR TWO...PULLING THE ASSOCIATED 
SURFACE COLD FRONT EASTWARD THROUGH THE SOUTHWESTERN GULF OF 
MEXICO AND SLACKENING THE PRESSURE GRADIENT OFF THE W COAST OF 
BAJA CALIFORNIA...WHERE WINDS ARE CURRENTLY AS HIGH AS 25 KT.  
AT THE SAME TIME...STRONG NORTHERLY FLOW SHOULD BLEED THROUGH 
THE ISTHMUS OF TEHUANTEPEC AS THE COLD FRONT IS FORCED EASTWARD 
THROUGH THE BAY OF CAMPECHE. A BRIEF MINIMAL GALE WIND EVENT IS 
EXPECTED IN THE GULF OF TEHUANTEPEC TUE AS A RESULT.

THE SUBTROPICAL RIDGE OVER N CENTRAL WATERS WILL SHIFT SLIGHTLY 
EASTWARD AND WEAKEN THROUGH THE WEEK AS THE LOW N OF HAWAII 
WEAKENS.  MUCH OF THE SHORTWAVE ENERGY ASSOCIATED WITH THIS CUT 
OFF LOW IS EXPECTED TO PHASE WITH THE NORTHERN STREAM OVER THE 
NEXT DAY OR TWO...PUSHING THE REMAINING ENERGY EASTWARD THROUGH 
N WATERS.  MEANWHILE...THE TROUGHING ASSOCIATED WITH THIS LOW 
WILL BE RELOADED WITH ENERGY CURRENTLY SW OF THE LOW.  THIS 
PATTERN WILL MAINTAIN THE MEAN TROUGHING OVER NW WATERS ON TUE 
AND WED.  AT THE SURFACE...THE RIDGE AXIS WILL SHIFT EASTWARD 
AND WINDS WILL GRADUALLY DIMINISH OVER WESTERN WATERS BETWEEN 
10N AND 20N WHERE THEY ARE CURRENTLY IN THE 20 TO 25 KT RANGE W 
OF 123W. FARTHER N...A STRONG MID LATITUDE SYSTEM WILL BRING NW 
SWELL TO N WATERS OVERNIGHT MON NIGHT.

SCATTEROMETER PASSES ACROSS THE GULF OF PAPAGAYO REGION THE PAST 
24 HOURS HAVE SHOWN A VERY SMALL AREA OF 20 KT WINDS...AND THESE 
WINDS SHOULD CONTINUE AT OR ABOVE 20 KT AND EXPAND IN AREAL 
COVERAGE DOWNWIND OF THE GULF AS STRONG TRADE WINDS MOVE THROUGH 
CENTRAL AMERICA. EXPECT THE HIGH PRESSURE RIDGE CURRENTLY OVER 
THE EASTERN GULF OF MEXICO TO BE FORCED SOUTHWARD INTO THE NW 
CARIBBEAN AS THE TROUGH PASSING THROUGH MEXICO PUSHES THE COLD 
FRONT OVER THE WESTERN GULF EASTWARD...ALLOWING THE PRESSURE 
GRADIENT TO BRIEFLY BUILD BETWEEN THIS RIDGE AND THE 
CLIMATOLOGICAL LOW PRESSURE OVER NORTHERN COLOMBIA.  ON 
TUE...THE WIND FIELD IS EXPECTED TO EXPAND FARTHER WEST OF THE 
GULF OF PAPAGAYO ON TUE AS A RESULT.  WINDS ARE EXPECTED TO 
REMAIN JUST BELOW 20 KT DOWNWIND OF THE GULF OF PANAMA THROUGH 
TUE.

THERE IS LITTLE CONVECTION OVER THE FORECAST AREA AT THIS TIME.  
WIDESPREAD SUBSIDENCE CAN BE FOUND OVER MUCH OF THE REGION SE OF 
A LINE FROM 18N102W TO 00N135W.  STRONG UPPER LEVEL CONVERGENCE 
ALONG 95W IS INHIBITING CONVECTION IN THE PORTION OF THE REGION 
WITH THE HIGHEST PRECIPITABLE WATER VALUES.  250 MB FLOW IN 
EXCESS OF 50 KT CAN BE FOUND OVER MUCH OF THE REGION N OF 
20N...ALSO INHIBITING CONVECTION.  THE BEST CHANCE OF CONVECTION 
DEVELOPING THIS PERIOD WILL BE IN THE AREA S OF 20N AND W OF THE 
AFOREMENTIONED LINE WHERE PRECIPITABLE WATER VALUES ARE NEAR 2 
INCHES AND BROAD UPPER LEVEL DIFFLUENCE CAN BE FOUND.

$$
SCHAUER CLARK/STRIPLING