000
AXPZ20 KNHC 200937
TWDEP 

TROPICAL WEATHER DISCUSSION  
NWS NATIONAL HURRICANE CENTER MIAMI FL
0404 UTC SUN FEB 20 2011

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 
0730 UTC.

...ITCZ...
THE INTERTROPICAL CONVERGENCE ZONE IS ANALYZED FROM 04N77W TO 
02N89W TO 03S105W TO 04N130W TO 06N140W. SCATTERED MODERATE 
CONVECTION LIES WITHIN 150 NM OF EITHER SIDE OF THE ITCZ AXIS 
BETWEEN 89W TO 100W. ISOLATED MODERATE CONVECTION IS WITHIN 360 
NM N OF THE ITCZ AXIS BETWEEN 122W AND 127W.

...DISCUSSION...
THE LONGWAVE UPPER PATTERN IS EXPECTED TO CHANGE LITTLE OVER THE 
NEXT TWO DAYS WITH A TROUGH AXIS GENERALLY EXTENDING FROM 
32N125W TO NEAR 05N130W AND BOOKENDED BY RIDGING WITH THE 
EASTERN RIDGE EXTENDING ALONG 95W TO AN ANTICYCLONE CENTERED 
AROUND 05N95W. CONVECTION ALONG THE ITCZ IS FOCUSED NEAR AREAS 
OF UPPER LEVEL DIFFLUENCE NEAR THE ANTICYCLONE AND ON THE SE 
SIDE OF THE TROUGH AXIS BETWEEN THE TROUGH AND ANTICYCLONE. 
VERTICAL LIFT IN THESE AREA HAS INCREASED LOW LEVEL CONVERGENCE 
AND ALLOWED MOSITURE TO POOL...WITH THE HIGHEST PRECIPITABLE 
WATER VALUES AND THE MOST VIGOROUS CONVECTION FOUND NEAR THE 
ANTICYCLONE. 

FARTHER N...HIGH PRES DOMINATES THE SURFACE WITH THE REMNANTS OF 
AN EARLIER COLD FRONT OVER NE WATERS NO LONGER EVIDENT AT THE 
SURFACE...BUT 20 KT NW WINDS CONTINUE TO IMPACT THE NE PORTION 
OF THE PACIFIC WATERS AS WELL AS THE NORTHERN GULF OF 
CALIFORNIA. MULTILAYERED CLOUDINESS EXTENDS E OF 130W AND N OF A 
LINE FROM 20N130W TO 28N111W...WITHIN THE REAR RIGHT QUADRANT OF 
THE 130 KT UPPER JET OVER NE WATERS. THE SAN DIEGO AND YUMA 
RADARS SHOW SHOWERS EXTENDING WELL INTO BAJA CALIFORNIA NORTE. 
THE SHORTWAVE TROUGH IN PLACE FROM NORTHERN CALIFORNIA INTO NE 
WATERS WILL BE REPLACED BY A NEW DEEP LAYER LOW THAT WILL MOVE 
INTO THE LONGWAVE TROUGH OVER NE WATERS BY TUE MORNING. 20 KT 
WINDS WILL SPREAD S THROUGH THE GULF OF CALIFORNIA TODAY BEFORE 
DIMINISHING AND WINDS WILL SHIFT E OVER THE PACIFIC TO ALONG THE 
COAST OF BAJA CALIFORNIA BY MON MORNING BEFORE DIMINISHING. 
MEANWHILE...NW WINDS WILL INCREASE TO 20 KT AHEAD OF THE NEXT 
SYSTEM AT THE END OF THE PERIOD TUE MORNING. THE PRES GRADIENT 
BETWEEN THE ANOMALOUSLY S ITCZ AND HIGH PRES TO THE N IS KEEPING 
A SMALL AREA OF FRESH TRADE WINDS OVER FAR W WATERS THIS MORNING 
THAT WILL EXPAND THROUGH MON MORNING UNDER SOUTH-EASTWARD 
MIGRATING HIGH PRES AND REMAIN UNCHANGED THROUGH TUE MORNING. 

GAP WINDS...
GULF OF PAPAGAYO...FRESH NE TRADE WINDS WILL CONTINUE TO SPILL 
FROM THE WESTERN CARIBBEAN INTO THE E PAC WITH THE NIGHTTIME 
MOUNTAIN DRAINAGE AIR MASS REINFORCING THE EASTERLY WINDS 
THROUGH PERIOD. 

GULF OF PANAMA...THE PRES GRADIENT OVER NW COLOMBIA WILL 
CONTINUE TO BE TIGHT ENOUGH TO SUPPORT FRESH NORTHERLY WINDS 
OVER GULF OF PANAMA TODAY THROUGH MON.

GULF OF TEHUANTEPEC...HIGH PRES OVER GULF OF MEXICO HAS BROUGHT 
A COLD AIR MASS THROUGH CHIVELA PASS RESULTING IN FRESH NORTH TO 
NORTHEAST WINDS IN GULF OF TEHUANTEPEC THROUGH THIS AFTERNOON.  
WIND ARE EXPECTED TO DIMINISH TO A MODERATE BREEZE AS HIGH PRES 
MOVES FURTHER E...VEERING WINDS OVER SW GULF OF MEXICO BY LATE 
SUN.
 
$$
SCHAUER