000
AXPZ20 KNHC 110334
TWDEP 

TROPICAL WEATHER DISCUSSION 
NWS NATIONAL HURRICANE CENTER MIAMI FL
0405 UTC FRI FEB 11 2011

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 
0330 UTC.

...ITCZ...
THE INTERTROPICAL CONVERGENCE ZONE IS ANALYZED FROM 04N77W TO 
05N100W TO 08N122W...CONTINUES FROM 06N130W TO 06N140W. NO 
SIGNIFICANT CONVECTION. 

...DISCUSSION...
ALOFT...STRONGLY POSITIVE TILT MID TO UPPER LEVEL TROUGH AXIS 
EXTENDS FROM WRN ARIZONA THROUGH 27N124W TO 17N140W...WITH A 
BASE NEAR 09N140W MOVING EASTWARD INTO THE FAR WESTERN FORECAST 
WATERS. AXIS OF THE SUBTROPICAL JET E OF THE TROUGH IS ADVECTING 
MID TO UPPER LEVEL MOISTURE INTO THE SOUTHERN BAJA CALIFORNIA 
PENINSULA AND NW MEXICO WITH CORE SPEEDS OF 65-80 KT NOTED. 
THIS AMPLIFIED UPPER LEVEL PATTERN APPEARS TEMPORARY AS MODEL 
GUIDANCE SUGGESTS THE UPPER RIDGE TO THE W OF THIS TROUGH 
CURRENTLY EXTENDING NE FROM HAWAII TO NEAR 40N136W WILL ENCROACH 
UPON THE POSITIVELY TILTED UPPER TROUGH...PINCHING OFF AN 
ANTICYCLONE NEAR 32N125W LATE FRI AND ALLOWING THE TROUGH TO 
LEAVE BEHIND AN UPPER LOW NEAR 16N135W.

SURFACE...A 1026 MB HIGH PRES CENTERED NEAR 37N133W IS EMBEDDED 
WITHIN A RIDGE AXIS WHICH EXTENDS SOUTHWESTWARD ACROSS THE NW 
PORTION OF THE DISCUSSION AREA TO JUST EAST OF THE HAWAIIAN 
ISLANDS NEAR 20N145W. THE HIGH AND RIDGES AXIS WILL MIGRATE 
SLOWLY E THROUGH SAT. THE PRES GRADIENT BETWEEN THE HIGH AND 
A SURFACE TROUGH OVER CALIFORNIA HAS RELAXED WITH WINDS 
REMAINING BELOW 20 KT GENERALLY N OF 20N WHILE SEAS OF 10 TO 11 
FT IN NW SWELL CONTINUE TO SUBSIDE. 

A SURFACE TROUGH ANALYZED FROM 10N123W TO 04N129W IS MOVING W 
10-15 KT. THE TROUGH HAS TIGHTENED THE GRADIENT BETWEEN THE HIGH
AND THE ITCZ WITH A BELT OF 20 KT NE TRADES OCCURRING FROM 06N 
TO 16N W OF THE TROUGH. THESE TRADES WILL MOVE WESTWARD IN 
TANDEM WITH THE TROUGH OVER THE NEXT 48 HOURS. 

GAP WINDS...
GULF OF TEHUANTEPEC...COLD AIR HAS SURGED THROUGH THE ISTHMUS 
OF TEHUANTEPEC AND HAS USHERED IN ANOTHER GALE FORCE WIND EVENT. 
A MUCH EARLIER 1538 UTC HIGH RESOLUTION ASCAT PASS SHOWED THE 
ONSET OF 35 KT WINDS IN THE GULF OF TEHUANTEPEC. MORE RECENTLY
SURFACE OBSERVATIONS FROM IXTEPEC INDICATED N WINDS OF 30 KT
OVER THE PAST FEW HOURS. THIS SURGE IS EXPECTED TO TAPER OFF 
EARLY FRI. NWP MODELS INDICATE A SECONDARY SURGE OF COLD DRY AIR 
WILL BRING GALE FORCE WINDS TO THE AREA ONCE AGAIN FRI NIGHT 
WITH WINDS INCREASING TO 40 TO 45 KT BY LATE SAT AND SEAS 
BUILDING 10 TO 16 FT. 

GULF OF PAPAGAYO...EASTERLY TRADE WINDS IN THE SOUTHWESTERN 
CARIBBEAN ARE SPILLING ACROSS THE MOUNTAINS OF COSTA RICA WITH 
WINDS TO 20 KT EXPECTED THROUGH THE REMAINDER OF THE PERIOD. THE 
STRONGEST WINDS ARE EXPECTED IN THE EARLY MORNING HOURS WHEN 
DRAINAGE FLOW IS AT A MAXIMUM.

GULF OF PANAMA...AS APPROACHING SURFACE TROUGHING TAKES 
RESIDENCE OVER THE NW CARIBBEAN SEA...THE PRESSURE GRADIENT IS 
EXPECTED TO BRIEFLY RELAX OVER THE SW CARIBBEAN. HOWEVER BY 
EARLY SAT...EASTERLY TRADES ARE EXPECTED TO SPREAD WESTWARD WITH 
DRAINAGE FLOW ACROSS THE ISTHMUS OF PANAMA INTO THE GULF 
REMAINING N OF 06N BETWEEN 78W AND 80W.

GULF OF CALIFORNIA...A TIGHT GRADIENT BETWEEN HIGH PRES OVER THE 
ROCKIES AND GREAT BASIN AND SURFACE TROUGHING OVER WESTERN 
MEXICO IS GENERATING NW WINDS WHICH ARE FUNNELING THROUGH THE 
GULF IN THE 20 TO 25 KT RANGE. WINDS WILL DIMINISH TO 20 KT 
TONIGHT AND REMAIN 20 KT THROUGH THE REMAINDER OF THE FORECAST 
PERIOD AS THE PRES GRADIENT GRADUALLY WEAKENS.

$$
COBB