000
AXPZ20 KNHC 161003
TWDEP 

TROPICAL WEATHER DISCUSSION    
NWS TPC/NATIONAL HURRICANE CENTER MIAMI FL
1005 UTC MON MAR 16 2009

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 
0900 UTC.

...ITCZ...

THE ITCZ AXIS EXTENDS FROM 05N77W TO 05N84W TO 03N99W...AND FROM 
06N119W TO 03N140W. NO SIGNIFICANT CONVECTION WAS NOTED NEAR THE 
ITCZ AXIS.

...DISCUSSION...

THE UPPER PATTERN ACROSS THE REGION REMAINS STAGNANT AND BLOCKED 
W OF 130W AS A DEEP LAYERED LOW PERSISTS WITHIN SEVERAL DEGREES 
N OF THE HAWAIIAN ISLANDS...AND DOWNSTREAM RIDGING PERSISTS. E 
OF THIS THE FLOW IS PROGRESSIVE N OF 15N WITH A MID TO UPPER 
LEVEL TROUGH MOVING EWD ACROSS TEXAS AND NRN MEXICO. THE 
STRONGEST SHORTWAVE ENERGY ASSOCIATED WITH THIS TROUGH HAS BEGIN 
TO LIFT OUT ACROSS NE MEXICO AND INTO SRN TEXAS...AND SHOULD 
CONTINUE LIFTING NE AND INTO THE LEADING EDGE OF THE BROADER 
TROUGH MOVING INTO THE CENTRAL U.S. OVER THE NEXT DAY OR TWO. 
THIS IS FORECAST TO PULL AN ASSOCIATED SURFACE COLD FRONT 
EASTWARD THROUGH THE SOUTHWESTERN GULF OF MEXICO AND GRADUALLY 
SLACKEN THE PRESSURE GRADIENT OFF THE W COAST OF BAJA 
CALIFORNIA...WHERE WINDS REMAIN NNW 20-25 KT. AS THIS OCCURS... 
STRONG NORTHERLY FLOW SHOULD BLEED THROUGH THE ISTHMUS OF 
TEHUANTEPEC AS THE COLD FRONT IS FORCED EASTWARD THROUGH THE BAY 
OF CAMPECHE. THIS WILL INDUCE A BRIEF MINIMAL GALE WIND EVENT BY 
24 HOURS IN THE GULF OF TEHUANTEPEC 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.  AS THE SURFACE RIDGE AXIS SHIFTS EASTWARD...WINDS WILL 
GRADUALLY DIMINISH OVER WESTERN WATERS BETWEEN 10N AND 20N WHERE 
THEY CONTINUE IN THE 20 TO 25 KT RANGE W OF 120W. 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 NEAR 20 KT AND DOWNWIND OF THE GULF OF PANAMA THROUGH TUE.

THERE IS LITTLE CONVECTION OF CONSEQUENCE 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.

$$
STRIPLING