000
AXPZ20 KNHC 071513
TWDEP 

TROPICAL WEATHER DISCUSSION                                      
NWS NATIONAL HURRICANE CENTER MIAMI FL                           
1605 UTC TUE MAY 07 2013

TROPICAL WEATHER DISCUSSION FOR THE EASTERN PACIFIC OCEAN FROM 
THE EQUATOR TO 32N...EAST OF 140W. THE FOLLOWING INFORMATION IS 
BASED ON SATELLITE IMAGERY...WEATHER OBSERVATIONS...RADAR...AND 
METEOROLOGICAL ANALYSIS.

BASED ON 1200 UTC SURFACE ANALYSIS AND SATELLITE IMAGERY THROUGH 
1245 UTC.

...INTERTROPICAL CONVERGENCE ZONE/MONSOON TROUGH...              
THE MONSOON TROUGH WAS ANALYZED FROM 05N77W TO 04N81W TO 08N86W 
TO 08N96W TO 10N112W THEN CONTINUES FROM 10N114W TO 07N118W. THE 
ITCZ AXIS WAS ANALYZED FROM 07N118W TO 06N125W TO 08N134W TO 
07N140W. SCATTERED MODERATE WITH ISOLATED STRONG CONVECTION WAS  
WITHIN 120 NM S OF THE AXIS W OF 134W. SCATTERED MODERATE 
CONVECTION WAS WITHIN 120 NM EITHER SIDE OF THE AXIS E OF 79W 
AND WITHIN 180 NM N OF THE AXIS BETWEEN 133W AND 138W. 

...DISCUSSION...                                             
RELATIVELY TRANQUIL MARINE CONDITIONS EXIST OVER THE ENTIRE 
FORECAST AREA...WITH WINDS 20 KT OR LESS AND SEAS LESS THAN 8 FT 
EXPECTED TO CONTINUE THROUGH AT LEAST THURSDAY MORNING. A SMALL 
AREA OF MODERATE TO FRESH TRADE WINDS JUST N OF THE ITCZ W OF 
135W...AS SEEN BY THE 0624 UTC ASCAT PASS...IS FORECAST TO 
EXPAND NORTHEASTWARD OVERNIGHT WED NIGHT AS THE FLAT SUBTROPICAL 
RIDGE ALONG 25N E OF 130W STRENGTHENS SLIGHTLY. A COLD FRONT 
WILL APPROACH NW WATERS BY THU...WITH SOUTHERLY FLOW AHEAD OF 
THE FRONT PICKING UP TO A FRESH BREEZE THERE AT THAT TIME. 

ELSEWHERE...A SURFACE TROUGH FROM 13N111W TO 07N114W INTERSECTS 
THE MONSOON TROUGH OVER CENTRAL WATERS. SCATTERED MODERATE 
CONVECTION WAS FROM 06N TO 11N BETWEEN 110W AND 118W NEAR THE 
TROUGH. THIS CONVECTION IS BEING ENHANCED BY THE UPPER LEVEL 
DIFFLUENCE ASSOCIATED WITH AN ANTICYCLONE CENTERED NEAR 
10N114W...DIRECTLY OVER THE SURFACE TROUGH. IN ADDITION...A SLUG 
OF LOW- TO MID-LEVEL MOISTURE WITH PRECIPITABLE WATER VALUES 
OVER 2.25 INCHES IS COINCIDENT WITH THE TROUGH AND PROVIDING 
FUEL FOR THE CONVECTION. THE TROUGH IS EXPECTED TO GRADUALLY 
WEAKEN OVER THE NEXT DAY OR SO AND THE ANTICYCLONE IS FORECAST 
TO MOVE EASTWARD TOWARD THE GULF OF TEHUANTEPEC. THIS WILL 
DECREASE THE CHANCE OF PRECIPITATION OVER CENTRAL WATERS NEAR 
THE MONSOON TROUGH/ITCZ.

THE STRONGEST CONVECTION OVER THE FORECAST AREA CAN BE FOUND S 
OF THE ITCZ OVER WESTERN WATERS. IT IS DESCRIBED IN THE SECTION 
ABOVE. THIS CONVECTION LIES UNDER THE REAR RIGHT QUADRANT OF A 
100 KT SOUTHWESTERLY UPPER JET WHOSE AXIS STRETCHES FROM 16N140W 
TO 25N130W TO NEAR GUAYMAS MEXICO. THE JET LIES ON THE EASTERN 
SIDE OF AN UPPER LEVEL TROUGH. THERE IS PLENTY OF LOW- TO MID-
LEVEL MOISTURE POOLED NEAR THIS AREA OF CONVECTION WHILE MID- TO 
HIGH-LEVEL MOISTURE IS BEING TRANSPORTED NORTHEASTWARD AWAY FROM 
THE ITCZ BY THE UPPER JET. MULTI-LAYERED CLOUDINESS WITH SOME 
SCATTERED SHOWERS CAN BE FOUND OVER MUCH OF THE AREA BETWEEN THE 
JET AXIS AND THE ITCZ W OF 124W WHERE THERE IS NO DEEP 
CONVECTION NOTED. THE UPPER TROUGH AND JET MAXIMUM ARE FORECAST 
TO SHIFT NORTHEASTWARD INTO THE REGION NEAR THE BAJA CALIFORNIA 
PENINSULA THROUGH THU MORNING.
  
$$
SCHAUER