000
AXPZ20 KNHC 172127
TWDEP 

TROPICAL WEATHER DISCUSSION  
NWS NATIONAL HURRICANE CENTER MIAMI FL
2205 UTC THU MAR 17 2011

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 
2045 UTC.

...ITCZ...

THE INTERTROPICAL CONVERGENCE AXIS IS CENTERED ALONG 03N78W TO 
04N105W TO 07N115W TO 04N130W TO 05N140W. SCATTERED MODERATE TO 
ISOLATED STRONG CONVECTION IS NOTED WITHIN 80 NM EITHER SIDE OF 
AXIS W OF 134W. SCATTERED MODERATE CONVECTION IS WITHIN 90 NM N 
OF AXIS BETWEEN 124W AND 130W. 

...DISCUSSION...

A RATHER BROAD UPPER LEVEL TROUGH EXTENDS FROM NEAR 30N130W TO 
NEAR 16N140W. A JET STREAM BRANCH WITH CORE WINDS OF 70-90 KT 
ROUNDS THE BASE OF THE TROUGH EXTENDING NE TO ACROSS NORTHERN 
BAJA CALIFORNIA. THESE WINDS ARE TRANSPORTING ABUNDANT MID TO 
UPPER LEVEL MOISTURE NORTHEASTWARD TO WELL INLAND THE 
INTERMOUNTAIN REGION OF THE U.S.

TO THE S OF THE UPPER LEVEL TROUGH...MODERATE TO STRONG 
SUBSIDENCE COVERS THE AREA FROM 15N TO 23N W OF 120W. THIS IS 
MAINTAINING RATHER DRY AND STABLE CONDITIONS AT THE SURFACE 
WHERE BROKEN STRATOCUMULUS CLOUDS MOVING SW TO W ARE SEEN. 

MODERATE TO STRONG SUBSIDENCE ALSO DOMINATES THE FAR EASTERN 
SECTION OF THE DISCUSSION AREA MAINLY S OF 20N AND E OF 
105W...WHERE ONLY A FEW LOW CLOUD STREAMERS WITH ISOLATED 
SHOWERS AND WEAK CONVECTION ARE OBSERVED.  

AT THE SURFACE...A WELL DEFINED SURFACE TROUGH IS WITHIN THE 
ITCZ AND EXTENDS FROM 10N116W TO 04N124W. THE TROUGH IS 
ENHANCING CONVECTION N OF THE ITCZ WITHIN 120 NM W OF THE 
TROUGH. STRONG HIGH PRES BUILDING SE IS PRESENT TO THE N OF 16N 
AND W OF 116W. THE PRES GRADIENT TO THE S OF THE RIDGE IS 
SUPPORTING NE-E TRADES OF 20-25 KT OVER AN AREA FROM 06N TO 28N 
W OF 130W AND N OF 14N BETWEEN 122W AND 130W. THE MOST RECENT 
ASCAT PASS CORROBORATED THESE WIND SPEEDS. THE RIDGE WILL SHIFT 
SOUTHWARD OVER N WATERS DURING THE NEXT FEW DAYS ALLOWING FOR 
THE AREA OF TRADES TO DIMINISH. FRESH TO STRONG NW WINDS ARE 
PRESENT E OF THE RIDGE IN THE FAR NE WATERS ALONG THE COAST OF 
BAJA CALIFORNIA PENINSULA. THESE WINDS ARE FORECAST TO LAST 
UNTIL EARLY SAT. A COLD FRONT CURRENTLY LOCATED WELL TO THE N OF 
THE FORECAST AREA ASSOCIATED WITH A DEVELOPING VIGOROUS UPPER 
LEVEL LOW IS FORECAST TO QUICKLY SWEEP SE ACROSS THE NW WATERS 
ON SAT PRECEDED AND FOLLOWED BY INCREASING WINDS. 

REGIONAL WATERS...W OF 110W...ARE DOMINATED BY LARGE NW SWELLS 
WHICH ARE FORECAST TO SUBSIDE THROUGH LATE FRI. HOWEVER...A NEW 
SET OF LARGE SWELLS IS FORECAST TO SPREAD SE INTO THE NORTHERN 
AND CENTRAL PORTIONS ON SAT.

GAP WINDS...
GULF OF TEHUANTEPEC...N WINDS WILL CONTINUE TO FUNNEL THROUGH 
THE ISTHMUS OF TEHUANTEPEC THROUGH THE FORECAST PERIOD. WINDS 
WILL PULSE TO 25 KT IN THE MORNING HOURS WHEN DRAINAGE FLOW 
THROUGH THE ISTHMUS WILL BE AT ITS DIURNAL MAXIMUM. AN EARLIER 
WINDSAT PASS PROVIDED OBSERVATIONS OF 25 KT THROUGH THE GULF OF 
TEHUANTEPEC.

GULF OF PAPAGAYO...NE TO E WINDS OF 20-25 KT WILL CONTINUE TO 
BLOW DOWNWIND OF THE GULF WITH LITTLE CHANGE OVER THE NEXT 48 
HOURS. SHIP A8FZ6 LOCATED NEAR 9.5N87W REPORTED 24 KT. 

GULF OF PANAMA...A STRONG PRES GRADIENT BETWEEN THE COLOMBIAN 
LOW AND HIGH PRES OVER CENTRAL AMERICA IS RESULTING IN NLY WINDS 
OF 20 KT ACROSS THE GULF OF PANAMA. WINDS ARE FORECAST TO 
INCREASE TO 25 KT IN 24 HOURS AS THEY EXTEND TO 4N. 

$$
GR/JA