000
AXPZ20 KNHC 062146
TWDEP 

TROPICAL WEATHER DISCUSSION                                     
NWS NATIONAL HURRICANE CENTER MIAMI FL                         
2205 UTC MON APR 06 2015

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 1800 UTC SURFACE ANALYSIS AND SATELLITE IMAGERY  
THROUGH 2145 UTC. 
 
...INTERTROPICAL CONVERGENCE ZONE/MONSOON TROUGH...
          
SCATTEROMETER WINDS INDICATE THAT THE ITCZ FORMS NEAR 03N96W  
AND EXTENDS W TO 03N111W...THEN TURNS NW TO 05N118W...THEN TURNS 
W TO BEYOND 05N140W. SCATTERED MODERATE CONVECTION IS OBSERVED E 
THE ITCZ WITHIN 75 NM EITHER SIDE OF A LINE FROM 02N86W TO 
04N91W. SCATTERED MODERATE ISOLATED STRONG CONVECTION IS NOTED 
ALONG THE ITCZ WITHIN 90 NM EITHER SIDE OF A LINE FROM 02N105W 
TO 03N113W. SIMILAR CONVECTION IS OBSERVED OVER AND TO THE N OF 
THE ITCZ WITHIN 120 NM EITHER SIDE OF A LINE FROM 03N117W TO 
12N124W... N OF THE ITCZ FROM 06-10N BETWEEN 126-138W. 
 
...DISCUSSION... 
    
AN UPPER LONG WAVE TROUGH DOMINATES THE WESTERN PORTION OF THE 
DISCUSSION AREA...AND IS CURRENTLY BEING REINFORCED BY AN 
EMBEDDED SHORTWAVE TROUGH EXTENDING SW FROM 32N122W TO 24N140W. 
UPPER MOISTURE CONTINUES TO SWING E THROUGH THE TROUGH TO THE N 
OF 31N...AND CONTINUES E ACROSS CALIFORNIA TO THE N OF 33N. THE 
ITCZ HAS BECOME CONVECTIVELY ACTIVE BETWEEN 120W AND AT LEAST 
160W...WITH THE RESULTANT DEBRIS MOISTURE ADVECTED NE AHEAD OF 
THE UPPER TROUGH WITHIN 480 NM EITHER SIDE OF A LINE FROM 
11N127W TO ACROSS THE GULF OF CALIFORNIA...CONTINUING NE ACROSS 
NORTHERN MEXICO...THEN TURNING E OVER MOST OF TEXAS BEFORE  
CONTINUING E ACROSS THE SOUTHERN CONUS. A 500 NM WIDE BAND OF 
UPPER DRY AIR SEPARATES THESE TWO MOISTURE PLUMES...AND EXTENDS 
FROM 19N140W TO ACROSS THE NORTHERN GULF OF CALIFORNIA AND 
ACROSS NEVADA SETTING UP A DISTINCT CONTRAST FROM DENSE UPPER 
MOISTURE...AND PRECIPITATION CHANCE...TO THE N AND S OF THE DRY 
BAND. 

AN UPPER LEVEL ANTICYCLONE IS CENTERED NEAR 12N104W WITH ITS 
ANTICYCLONIC ENVELOPE OF DRY UPPER AIR COVERING THE DISCUSSION 
AREA FROM 04-20N BETWEEN 110-75W WITH ONLY THE SMALL AREAS OF 
CONVECTION PREVIOUSLY DESCRIBED ALONG THE SOUTHERN EDGE OF THE 
UPPER SUBSIDENCE.
 
AT THE LOW LEVELS A SURFACE RIDGE EXTENDS FROM 30N140W TO      
16N104W. THE RIDGE WILL SHIFT SOUTHWARD ON TUE ALLOWING A COLD 
FRONT TO SWEEP RAPIDLY E ACROSS THE DISCUSSION AREA TO THE N OF 
29.5N...WITH THE FRONT PASSING ACROSS THE NORTHERN GULF OF 
CALIFORNIA EARLY WED WITH THE RIDGE THEN EXTENDING FROM 32N127W 
TO 15N100W. THE POST-FRONTAL NW FLOW IS EXPECTED TO INCREASE TO 
20-25 KT ALONG THE NW COAST OF THE BAJA CALIFORNIA PENINSULA 
BRIEFLY ON WED.   
 
THE GRADIENT CURRENTLY SW OF THE RIDGE IS SUPPORTING NE TRADES 
OF 15-20 KT ACROSS THE DISCUSSION WATERS BETWEEN THE ITCZ AND 
22N. LONG PERIOD NE...S AND NW SWELL ARE MIXING WITH COMBINED 
SEAS OF 7-10 FT...PER A RECENT ALTIMETER PASS...ACROSS THE 
DISCUSSION WATERS FROM 07-14N BETWEEN 132-140W. THE N SWELL 
COMPONENT WILL GRADUALLY SUBSIDE THROUGH THE MIDDLE OF THE WEEK 
AS THE NE TRADE SWELL MIXES WITH CROSS EQUATORIAL SOUTHERLY AND 
BUILDS THE COMBINED SEAS TO 7-8 FT ACROSS THE TROPICS N OF 
THE ITCZ AND W OF 118W. 
   
GULF OF CALIFORNIA...GUIDANCE IS SUGGESTING THAT THE NW FLOW    
WILL INCREASE TO 20-25 KT ACROSS THE SOUTHERN GULF OF CALIFORNIA 
LATE WED. 

GULF OF TEHUANTEPEC...EXPECT A NORTHERLY 20-25 KT 
DRAINAGE SURGE LATE TONIGHT AND AGAIN ON TUE NIGHT.
 
GULF OF PAPAGAYO...EXPECT ENE 20-30 KT NOCTURNAL DRAINAGE  
TONIGHT INTO EARLY TUE ACROSS THE PACIFIC WATERS FROM 09-13N 
BETWEEN 86-93W...WITH SEAS BUILDING TO 10 FT. ANOTHER STRONG 
EVENT IS EXPECTED TUE NIGHT...THEN BRIEF 20-25 KT SURGES 
EXPECTED ON WED AND THU NIGHTS.

GULF OF PANAMA...EXPECT STRONG NORTHERLY WINDS TO BRIEFLY  
DEVELOP ACROSS THE WESTERN GULF OF PANAMA TONIGHT AND EXTEND AS 
FAR S AS 05N82W. OTHERWISE MODERATE TO FRESH NORTHERLY WINDS ARE 
EXPECTED ACROSS THE GULF OF PANAMA AND DOWNWIND TO ABOUT 06N 
THROUGH EARLY WED.

 

$$ 
NELSON