000
AXPZ20 KNHC 191607
TWDEP 

TROPICAL WEATHER DISCUSSION                                    
NWS NATIONAL HURRICANE CENTER MIAMI FL                        
1605 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 1200 UTC SURFACE ANALYSIS AND SATELLITE IMAGERY THROUGH 
1545 UTC.

...INTERTROPICAL CONVERGENCE ZONE/MONSOON TROUGH...             

THE MONSOON TROUGH AXIS EXETNDS FROM 1085W TO 05N94W WHERE LOW 
LEVEL WINDS SUGGEST IT TRANSITIONS TO THE ITCZ AXIS TO 05N94W TO 
02N114W TO 03N130W TO 041N40W. SCATTERED MODERATE/ISOLATED 
STRONG CONVECTION IS WITHIN 60 NM OF THE AXIS BETWEEN 84W-
87W...AND BETWEEN 89W-92W. SIMILAR ACTIVITY IS WITHIN 120 NM N 
OF THE AXIS BETWEEN 128W-131W...AND WITHIN 120 NM S OF THE AXIS 
BETWEEN 132W-136W. 

...DISCUSSION...                                                

A LONG WAVE TROUGH EXTENDS FROM WELL NE OF THE REGION SWWD 
THROUGH NE MEXICO TO A DEVELOPING UPPER LOW AT 15N116W TO NEAR 
07N121W. UPPER DIVERGENCE E OF THE TROUGH IS ENHANCING 
CONVECTION ASSOCIATED WITH THE ITCZ AS DESCRIBED ABOVE. TO THE 
W OF THE TROUGH...HIGHLY AMPLIFIED UPPER RIDGING IS EVIDENT 
EXTENDING FROM A RIDGE CREST OVER THE U.S. PACIFIC NW SSW 
THROUGH 32N127W TO 20N130W TO NEAR 06N136W. THE TROUGH IS 
FORECAST TO LIFT NE THROUGH THU LEAVING BEHIND THE UPPER LOW
...WHICH WILL MOVE ESE.

SATELLITE WATER VAPOR IMAGERY SHOWS MODERATE SUBSIDENCE ALOFT 
OVER THE EASTERN PORTION OF THE AREA WITHIN ABOUT 510 NM EITHER 
SIDE OF THE AFOREMENTIONED TROUGH. THIS IS INDUCING RATHER DRY 
AND STABLE ATMOSPHERIC CONDITIONS OVER THIS AREA WITH MOSTLY 
CLEAR SKIES. 
 
A WEAKENING DEEP-LAYER LOW MOVING NEWD IS N OF THE AREA AT 
40N139W WITH A TROUGH SW TO WELL W OF THE AREA. THE COMBINATION 
OF AN UPPER LEVEL JET ON THE SE PERIPHERY OF THE LOW AND THE 
HIGHLY AMPLIFIED RIDGE OVER THE WESTERN PORTION IS TRANSPORTING 
AMPLE DEEP ATMOSPHERIC MOISTURE NE AND E ACROSS THE WESTERN AND 
FAR NORTHERN PORTIONS OF THE AREA. POSSIBLE PATCHES OF RAIN WITH 
SCATTERED SHOWERS ARE NOTED N OF ABOUT 19N W OF 130W...AND N OF 
28N E OF 130W. THE UPPER LOW WILL CONTINUE TO WEAKEN AS IT MOVES 
NEWD THROUGH WED WITH ITS REMNANTS EXPECTED TO BE PICKED UP BY A 
NORTHERN STREAM TROUGH TODAY. A COLD FRONT ASSOCIATED WITH THE 
LOW HAS MOVED INTO THE FAR NW WATERS...BUT HAS BEGUN TO WEAKEN. 
THE FRONT WILL CONTINUE TO WEAKEN OVER THE NW WATERS THROUGH 
WED. ITS ASSOCIATED MOISTURE AND PRECIPITATION IS TIED INTO THE 
AREA OF CLOUDS/PRECIPITATION EARLIER DESCRIBED. 

AT THE SURFACE...A 1020 MB HIGH CENTER IS N OF THE AREA AT
33N125W WITH A RIDGE SE TO NEAR 19N110W. HIGH PRES COVERS THE
AREA N OF 18N. THE WEAKER PRES GRADIENT ON THE SOUTHERN PERIPHERY
OF THIS RIDGE IS ONLY ALLOWING FOR WEAK NE TRADE WINDS OF ABOUT 
15-20 KT TO PERSIST ACROSS THE CENTRAL AND WESTERN PORTIONS OF 
THE DISCUSSION AREA.

SEAS IN THE 8-9 FT RANGE DUE TO PRIMARILY A SW SWELL COMPONENT 
ARE CONFINED FROM 02N TO 08N BETWEEN 114W AND 137W. THE AREA OF 
OF SWELLS AND NE 15-20 KT TRADE WINDS IS FORECAST TO SHRINK 
SLIGHTLY OVER THE NEXT 48 HRS AS THE HIGH CENTER N OF THE AREA 
SHIFTS S AND SW AND WEAKENS...AND IS REPLACED BY A BIT STRONGER 
RIDGE THAT BUILDS S OVER THE WESTERN PORTION. 

$$
AGUIRRE