000
AXPZ20 KNHC 070913
TWDEP 

TROPICAL WEATHER DISCUSSION  
NWS NATIONAL HURRICANE CENTER MIAMI FL
1005 UTC MON MAR 07 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 
0800 UTC.

...ITCZ...

THE INTERTROPICAL CONVERGENCE ZONE AXIS IS ANALYZED FROM 04N83W 
TO 01N98W TO 05N105W TO 05N120W TO 03N140W. SCATTERED MODERATE 
CONVECTION LIES WITHIN 210 NM EITHER SIDE OF THE ITCZ AXIS 
BETWEEN 111W AND 124W WHILE ISOLATED MODERATE CONVECTION IS 
WITHIN 90 NM N AND 45 NM S OF THE ITCZ AXIS BETWEEN 87W AND 95W. 
A TROUGH IS EMBEDDED IN THE ITCZ FROM 06N102W TO 00N104W AND 
SCATTERED MODERATE CONVECTION LIES WITHIN 180 NM W AND 120 NM E 
OF THE TROUGH AXIS N OF 04N.

...DISCUSSION...

W-SW FLOW ALOFT AT 30-50 KT IS PREVALENT ACROSS THE MAJORITY OF 
THE AREA FROM 05N TO 20N E OF 130W WITH MAINLY DRY AND STABLE 
AIR IN PLACE BETWEEN THE ITCZ AND 20N. THESE CONDITIONS ARE 
LIMITING CONVECTION OVER MUCH OF THE REGION. CONVECTION IS BEING 
ENHANCED ALONG THE ITCZ BETWEEN 111W AND 124W AS DESCRIBED IN 
THE SECTION ABOVE WITHIN THE AREA OF A PRECIPITABLE WATER MAXIMA 
AND UNDER A REGION OF UPPER LEVEL DIFFLUENCE. 

A POSITIVELY TILTED UPPER TROUGH IS APPROACHING THE NW CORNER OF 
THE AREA FROM THE W WITH A 60-80 KT JET AXIS AHEAD OF THE TROUGH 
ADVECTING PLENTIFUL MOISTURE FROM THE DEEP TROPICS ACROSS THE 
NORTHERN WATERS AROUND A WEAKENING UPPER RIDGE CENTERED FROM AN 
ANTICYCLONE LOCATED NEAR 21N116W. A WEAK UPPER LOW LIES BETWEEN 
THE ANTICYCLONE AND THE POSITIVELY TILTED TROUGH. THE LOW WILL 
BE PICKED UP BY THE POSITIVELY TILTED TROUGH AS IT ADVANCES 
EASTWARD AND WEAKENS OVER THE NEXT DAY OR TWO. 

AT THE SURFACE...A DISSIPATING COLD FRONT FROM 32N122W TO 
27N132W IS SUPPORTED BY THE ABOVE MENTIONED POSITIVELY TILTED 
UPPER TROUGH. N TO NE WINDS TO 20 KT WITH SEAS TO 8 FT IN NW 
SWELL ARE BEHIND THE FRONT. THE FRONT WILL DISSIPATE LATER TODAY 
AND A TIGHT PRES GRADIENT WILL SET UP JUST W OF THE BAJA 
CALIFORNIA PENINSULA. GALE CONDITIONS ARE EXPECTED N OF 31N OFF 
THE CALIFORNIA COAST BY TONIGHT AND WILL USHER IN NW SWELL UP TO 
11 FT W OF THE PENINSULA TUE MORNING WHILE NW-N 20-25 KT WINDS 
EXPAND SOUTHWARD W OF THE PENINSULA. BY WED MORNING...THE 
GRADIENT SHOULD RELAX AND ALLOW WINDS TO DROP BELOW ADVISORY 
CRITERIA...BUT THE NW SWELL WILL KEEP SEAS TO 8 FT.

GAP WINDS...
GULF OF CALIFORNIA...A COLD FRONT WILL MOVE THROUGH THE NORTHERN 
GULF OF CALIFORNIAN BY TUE MORNING AND NORTHERLY WINDS ARE 
EXPECTED TO INCREASE TO 20 KT BEHIND THE FRONT TUE AFTERNOON 
THROUGH THE END OF THE FORECAST PERIOD WED MORNING.

GULF OF TEHUANTEPEC...A COLD FRONT THAT PASSED THROUGH THE 
WESTERN GULF OF MEXICO IS USHERING IN STRONG NORTHERLY WINDS IN 
THE GULF OF TEHUANTEPEC AND A GALE WARNING CONTINUES THROUGH 12Z 
TODAY. SHIP ZCDF4 CONFIRMED WINDS AT GALE FORCE AT 04Z. WINDS 
WILL QUICKLY DIMINISH TO LESS THAN 20 KT BY MON EVENING AS THE 
FRONT AND THE HIGH PRES BEHIND IT CONTINUE TO MOVE EASTWARD AWAY 
FROM THE AREA.

GULF OF PAPAGAYO...THE 0246Z ASCAT PASS SHOWS WINDS TO 20 KT IN 
THE GULF OF PAPAGAYO. WINDS ARE EXPECTED TO PULSE TO 20 KT 
DURING THE MORNING HOURS TODAY AND TUE AS THE PRES GRADIENT 
INCREASES BEHIND THE AFOREMENTIONED COLD FRONT. 

GULF OF PANAMA...SHIP DFFA2 REPORTED 20 KT N WINDS S OF THE GULF 
OF PANAMA NEAR 05N80W AT 06Z THIS MORNING. THESE FRESH N WINDS 
ARE EXPECTED TO DIMINISH BELOW ADVISORY CRITERIA BY THIS 
AFTERNOON.

$$
SCHAUER/LEWITSKY