000
AXPZ20 KNHC 190909
TWDEP 

TROPICAL WEATHER DISCUSSION                                    
NWS NATIONAL HURRICANE CENTER MIAMI FL                        
1005 UTC TUE MAR 19 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 0600 UTC SURFACE ANALYSIS AND SATELLITE IMAGERY THROUGH 
0700 UTC.

...INTERTROPICAL CONVERGENCE ZONE/MONSOON TROUGH...             
THE MONSOON TROUGH AXIS WAS ANALYZED FROM 10N85W TO 04N94W. THE 
ITCZ AXIS WAS ANALYZED FROM 04N94W TO 01N120W TO 05N140W. 
SCATTERED MODERATE CONVECTION WAS WITHIN 210 NM N OF THE AXIS 
BETWEEN 102W AND 113W AS WELL AS WITHIN 120 NM N AND 90 NM S OF 
THE AXIS W OF 131W.

...DISCUSSION...                                                
A POSITIVELY TILTED UPPER-LEVEL TROUGH EXTENDS ACROSS MEXICO 
FROM THE TEXAS BIG BEND THROUGH THE MOUTH OF THE GULF OF 
CALIFORNIA TO NEAR 13N118W. WHILE THE TROUGH HAS DISSIPATED IN 
THE MID-LEVELS...A 70 KT SOUTHERN STREAM UPPER JET REMAINS ON 
ITS SE SIDE. THE LOW- TO MID-LEVEL MOISTURE THAT PREVIOUSLY FED 
INTO THE JET AND SUPPLIED PRECIPITATION AND MULTI-LAYERED CLOUDS 
ALONG THE JET AXIS HAS RETREATED SOUTHWARD. THE PORTION OF THE 
TROUGH OVER MEXICO IS EXPECTED TO BE PICKED UP BY A NORTHERN 
STREAM TROUGH OVER THE U.S. PLAINS AND MISSISSIPPI VALLEY TODAY 
THROUGH WED...LEAVING AN UPPER LOW BEHIND NEAR 17N110W. 

A WEAKENING DEEP-LAYER LOW LIES NEAR 40N140W. THE SOUTHWESTERLY 
UPPER JET ON THE SE SIDE OF THE LOW IS TRANSPORTING MOISTURE 
INTO WESTERN WATERS PRIMARILY W OF A LINE FROM 32N122W TO 
10N137W...WITH SHOWER ACTIVITY AND POSSIBLY AND ISOLATED 
THUNDERSTORM BELIEVED TO BE FOUND MAINLY W OF 135W. THE COLD 
FRONT ASSOCIATED WITH THIS LOW IS CLIPPING NW WATERS AND LIES 
FROM 32N138W TO 22N150W. THE UPPER LOW WILL CONTINUE TO WEAKEN 
AS IT MOVES NORTHEASTWARD...WITH ITS REMNANTS EXPECTED TO BE 
PICKED UP BY A NORTHERN STREAM TROUGH TODAY. THE COLD FRONT IS 
EXPECTED TO DISSIPATE S OF 32N AS IT MOVES THROUGH NW WATERS 
OVERNIGHT TONIGHT. PRECIPITATION WILL BE ITS MAIN CONTRIBUTION 
OF THE SENSIBLE WEATHER OVER THE FORECAST AREA.

HIGH PRESSURE IN THE EASTERN PACIFIC HAS BEEN WEAKENED AND 
FORCED SOUTHWARD BY THE AFOREMENTIONED DEEP-LAYER LOW. RIDGE 
AXES EXTEND FROM 1022 MB HIGH PRES NEAR 34N125W THROUGH 23N122W 
TO 18N116W AS WELL AS FROM THE HIGH THROUGH 27N130W TO 23N147W. 
THE PRESSURE GRADIENT IS WEAK BETWEEN THESE RIDGES AND THE ITCZ 
OVER WESTERN WATERS. MODERATE TO FRESH TRADES ARE CONFINED 
BETWEEN THE ITCZ AND 20N. LINGERING E-NE SWELL FROM AN EARLIER 
GAP WIND EVENT CONTINUES TO PROPAGATE WESTWARD INTO THE AREA OF 
FRESH TRADE WINDS SEEN BY THE 0456 UTC ASCAT PASS AND 0216 UTC 
WINDSAT PASS. SEAS TO 8 FT ARE BELIEVED TO LIE FROM 02N-08N 
BETWEEN 115W AND 126W THIS MORNING...BUT THE JASON1 AND JASON2 
PASSES FROM AROUND 0230 UTC AND 0430 UTC MISSED THIS AREA. THE 
AREA OF FRESH WINDS WILL SHIFT NORTHWARD TODAY AND DRAG THE AREA 
OF SEAS TO 8 FT SLIGHTLY NORTHWARD AS WELL. THE OVERALL AREA OF 
SEAS TO 8 FT SHOULD SHRINK CONSIDERABLY WED AS THE TRADE WINDS 
DIMINISH TO A MODERATE BREEZE AND THE HIGH PRESSURE REORGANIZES 
TO THE NW.

$$
SCHAUER