000
AXPZ20 KNHC 100921
TWDEP 

TROPICAL WEATHER DISCUSSION   
NWS NATIONAL HURRICANE CENTER MIAMI FL
1005 UTC SUN APR 10 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 
0645 UTC.

...ITCZ...

THE INTERTROPICAL CONVERGENCE ZONE AXIS WAS ANALYZED FROM 07N78W 
TO 05N67W TO 04N103W TO 06N122W TO 00N134W. SCATTERED MODERATE 
CONVECTION LIES WITHIN 210 NM N AND 150 NM S OF THE ITCZ AXIS 
BETWEEN 86W AND 109W. A TROUGH IS EMBEDDED IN THE ITCZ FROM 
09N122W TO 01N126W. SCATTERED MODERATE WITH ISOLATED STRONG 
CONVECTION LIES WITHIN 180 NM EITHER SIDE OF TROUGH.

...DISCUSSION...

AN WEAK UPPER LOW LIES NEAR 26N138W. 50-70 KT WEST-SOUTHWEST 
WINDS ON THE SE SIDE OF THE LOW ARE TRANSPORTING SOME MID TO 
UPPER LEVEL MOISTURE INTO THE NW PORTION OF THE AREA WHICH IS 
MARKED BY MULTI-LAYERED CLOUDINESS N OF 17N W OF 130W AS A 
RESULT. THIS LOW WILL BE OVERTAKEN LATER TODAY BY A NORTHERN 
STREAM BROAD TROUGH CURRENTLY NW OF THE AREA. A COLD FRONT 
ASSOCIATED WITH THIS NORTHERN STREAM TROUGH IS SLOWLY 
APPROACHING THE NW PORTION OF THE FORECAST AREA...BUT SHOULD 
WEAKEN AS IT MOVES S OF 32N THIS AFTERNOON. THE APPROACH OF THIS 
FRONT WILL WEAKEN THE 1028 MB SUBTROPICAL HIGH NEAR 30N135W AND 
SHIFT IT SOUTHEASTWARD TODAY. THE DOMINANT HIGH PRES WILL SHIFT 
TO BEHIND THE FRONT BY MON MORNING.

FRESH TRADE WINDS LIE OVER MUCH OF THE W CENTRAL PORTION OF THE 
FORECAST AREA ACCORDING TO THE 0608 UTC ASCAT PASS. AS THE HIGH 
PRES TO THE N WEAKENS AND REORGANIZES TO THE W...LOOK FOR THE 
AREA OF FRESH NORTHEAST TRADES TO SHIFT W AND SLIGHTLY S IN 
RESPONSE.

AN UPPER TROUGH LIES FROM THE GREAT SALT LAKE INTO NE WATERS 
NEAR 25N123W. THIS TROUGH WILL PROCEED THROUGH THE SW CONUS AND 
INTO NORTHERN MEXICO TODAY. AT THE SURFACE...THE PRES GRADIENT 
WILL TIGHTEN BETWEEN THE SUBTROPICAL RIDGE W OF THE BAJA 
CALIFORNIA PENINSULA AND A LOW PRES SYSTEM MOVING THROUGH 
SOUTHERN TEXAS AND NE MEXICO. FRESH NORTHERLY WINDS ARE EXPECTED 
TO COMMENCE IN THE CENTRAL GULF OF CALIFORNIA LATER THIS MORNING 
AS THE PRES GRADIENT INCREASES. THESE WINDS WILL EXPAND TO 
ENCOMPASS THE MAJORITY OF THE GULF BY TONIGHT. THE PRESSURE 
GRADIENT W OF THE BAJA CALIFORNIA COAST WILL TIGHTEN TO SUPPORT 
20 KT NW TO N WINDS BY LATER THIS MORNING AS WELL. THESE WINDS 
WILL GRADUALLY EXPAND W THROUGH THE FORECAST PERIOD. 
MEANWHILE...THE PRES GRADIENT HAS ALREADY BECOME STRONG ENOUGH 
ON THE EASTERN EDGE OF THE SURFACE RIDGE NEAR CABO CORRIENTES 
MEXICO TO SUPPORT FRESH TO STRONG NW TO N WINDS WHICH WILL 
REMAIN IN PLACE THROUGH MON MORNING BEFORE DIMINISHING.

A SURFACE TROUGH IS EMBEDDED IN THE ITCZ FROM 09N122W TO 
01N126W. THIS TROUGH COINCIDES WITH AN AREA OF INCREASED 
AVAILABLE MOISTURE ACCORDING TO THE LATEST PRECIPITABLE WATER 
SATELLITE IMAGERY. THE DIFFLUENT REAR RIGHT QUADRANT OF THE MID 
TO UPPER LEVEL TROUGH OVER NE WATERS HAS TAPPED INTO TROPICAL 
MOISTURE ALONG THE ITCZ NEAR THIS SURFACE TROUGH. CONVECTION 
NEAR THE TROUGH IS DESCRIBED ABOVE. CONVECTIVE BLOW OFF EXTENDS 
NE OF THE SURFACE TROUGH TO THE SOUTHERN TIP OF BAJA CALIFORNIA.

AN ANTICYCLONE ALOFT NEAR 15N93W EXTENDS A RIDGE SOUTHWESTWARD 
TO A COL NEAR 06N120W. BROAD DIFFLUENCE ALOFT BETWEEN THE 
ANTICYCLONE AND A 30-35 KT EASTERLY JET ALOFT ALONG THE EQUATOR 
E OF 110W IS ENHANCING VERTICAL LIFT NEAR THE ITCZ. THIS AREA 
COINCIDES WITH A MAXIMUM IN PRECIPITABLE WATER AS WELL. 
CONVECTION DESCRIBED IN THE ITCZ SECTION ABOVE HAS BEEN 
IDENTIFIED WITHIN THIS AREA. 

$$
SCHAUER