000
AXPZ20 KNHC 230950
TWDEP 

TROPICAL WEATHER DISCUSSION                                      
NWS NATIONAL HURRICANE CENTER MIAMI FL                           
1005 UTC SUN JUN 23 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 
0945 UTC.

...SPECIAL FEATURES...
A NEARLY STATIONARY 1006 MB SURFACE LOW AT 12N103W CONTINUES TO 
BECOME BETTER ORGANIZED...BUT IS STILL SHEARED FROM THE 
NE...WITH SCATTERED MODERATE TO STRONG CONVECTION NOTED IN BANDS 
WITHIN 390 NM OVER THE SW QUADRANT...AND ALSO WITHIN 300 NM OVER 
THE NW QUADRANT. MODEL CONSENSUS AGREE WITH CONTINUED 
DEVELOPMENT AND TROPICAL CYCLONE FORMATION IS POSSIBLE.

A NEARLY STATIONARY 1008 MB LOW PRESSURE IS NEAR 14.5N 114.5W WITH 
SCATTERED MODERATE ISOLATED STRONG CONVECTION NOTED WITHIN 60 NM 
OF 14N115W. THE WINDOW OF OPPORTUNITY FOR THIS LOW TO DEVELOP IS 
CLOSING QUICKLY WITH TROPICAL CYCLONE FORMATION STILL POSSIBLE 
EARLY TODAY. THEREAFTER THE THE STRONGER LOW PRESSURE SYSTEM 
FURTHER E WILL BECOME MORE EVEN MORE DOMINANT. THIS LOW IS 
EXPECTED TO WEAKEN TO AN OPEN TROUGH TONIGHT INTO MON...AND THEN 
LOSE IDENTITY BY MON NIGHT.

...TROPICAL WAVE...
A TROPICAL WAVE IS ANALYZED FROM 10N TO 17N ALONG 85W. E WINDS
WILL INCREASE TO 15-20 KT TODAY AND TONIGHT ACROSS THE GULF OF
PAPAGAYO AND THE PACIFIC WATERS DOWNSTREAM FROM 10N-13N TO THE
E OF 90W AS A TROPICAL WAVE MOVES THROUGH THE AREA. THE WAVE 
IS EXPECTED TO LOSE IDENTITY IN THE MONSOON FLOW TONIGHT. 

...INTERTROPICAL CONVERGENCE ZONE/MONSOON TROUGH...            
THE MONSOON TROUGH AXIS EXTENDS W ALONG 09.5N ACROSS THE 
CARIBBEAN FROM COLOMBIA TO ACROSS COSTA RICA AT 10N86W TO 
10N90W...THEN TURNS NW LOSING IDENTITY NEAR A DEVELOPING LOW 
PRES CENTER AT 12N103W. THE MONSOON TROUGH RESUMES JUST SW OF A 
SECOND LOW PRESSURE CENTER AT 14.5N 114.5W...AND CONTINUES SW TO 
10N131W WHERE SCATTEROMETER WINDS INDICATE A TRANSITION TO AN 
INTERTROPICAL CONVERGENCE ZONE WHICH IN TURN CONTINUES W TO 
BEYOND 09N140W. EXCEPT AS PREVIOUSLY MENTIONED AROUND THE TWO 
SURFACE LOWS...SCATTERED MODERATE ISOLATED STRONG CONVECTION 
WITH FREQUENT LIGHTNING IS OBSERVED WITHIN 60 NM EITHER SIDE OF 
A LINE FROM 04N77W TO 07N80W TO 08N83W TO 06N87W...WITHIN 90 NM 
EITHER SIDE OF A LINE FROM 06N91W TO 12N98W. ISOLATED MODERATE 
TO STRONG CONVECTION IS NOTED WITHIN 30 NM EITHER SIDE OF A LINE 
FROM 11N113W TO 12N118W AND FROM 07.5N TO 11N BETWEEN 136W AND 
140W. 

SCATTERED MODERATE ISOLATED STRONG CONVECTION WITH FREQUENT 
LIGHTNING STRIKES IS OBSERVED RUNNING PARALLEL TO COAST OF 
CENTRAL AMERICA WITHIN 75 NM EITHER SIDE OF A LINE FROM 12.5N90W 
TO 18N104W.

...DISCUSSION... 
A SMALL UPPER LEVEL CYCLONE IS QUASI STATIONARY AT 19N106W WITH 
AN UPPER TROUGH EXTENDING WSW THROUGH 18N125W AND INTO ANOTHER 
UPPER CYCLONE OVER THE TROPICS AT 14N140W. THIS UPPER TROUGH  
CONTINUES TO SEPARATE THE UPPER FLOW ACROSS THE DISCUSSION AREA 
W OF 105W. AN ANTICYCLONE IS CENTERED AT 24N124W WITH A 
STATIONARY UPPER RIDGE EXTENDING E TO A CREST OVER THE GULF OF 
CALIFORNIA NEAR 25N108W...AND AN UPPER RIDGE ALSO EXTENDS W TO A 
SHARP CREST AT 21N135W. A NARROW BAND OF UPPER MOISTURE... 
ORIGINATING FROM ITCZ CONVECTION W OF 155W...IS STREAMING NE 
ACROSS THE DISCUSSION AREA ALONG THE NW PERIPHERY OF THE 
RIDGE...ROUGHLY WITHIN 120 NM OF A LINE FROM 25N140W TO 30N123W 
WHERE IS SEEMS TO EVAPORATE. OTHERWISE...THE UPPER LEVELS APPEAR 
VERY DRY N OF 18N W OF 106W. 

AN UPPER ANTICYCLONE IS CENTERED NEAR 17N114W...WITH A RIDGE 
EXTENDING E TO 16N103W...AND A RIDGE EXTENDING W TO A CREST AT 
17N135W. THE ASSOCIATED UPPER DIFFLUENCE IS ENHANCING THE 
CONVECTION PREVIOUSLY DESCRIBED ALONG THE MONSOON TROUGH AND 
NEAR THE TWO EMBEDDED SURFACE LOWS. THE DEBRIS MOISTURE W OF 
105W EVAPORATES WITHIN ABOUT 240 NM N OF THE CONVECTIVE 
CLUSTERS. DENSE UPPER MOISTURE IS OBSERVED ACROSS THE TROPICS S 
OF 18N BETWEEN 77W-105W. UPPER DRY AIR IS SUPPRESSING CONVECTION 
S OF 09N BETWEEN 111W-138W.

A 1026 MB SURFACE HIGH IS CENTERED NEAR 32N143W WITH A RIDGE 
EXTENDING SE TO 19N115W. NORTHERLY WINDS AT 15-20 KT ARE 
OCCURRING E OF THE RIDGE...GENERALLY FROM 28N-30N BETWEEN 118W-
125W...WITH SEAS 7-8 FT IN N SWELL...WITH THE 8 FT SEAS TO THE N 
OF 30N. THE GRADIENT WILL CONTINUE TO SUPPORT THESE CONDITIONS 
THROUGH TONIGHT...THEN THE GRADIENT WILL RELAX ON MON. NE TRADES 
AREA ARE AT 15-20 KT SW OF THE RIDGE ACROSS THE WATERS W OF 130W 
WITH SEAS 6-8 FT IN THE NE SWELL. THE AFFECTED AREA OF 8 FT SEAS 
IS EXPECTED TO SHIFT W OF 140W LATE TODAY.  

NE WINDS AT 10-15 KT ARE EXPECTED ACROSS THE GULF OF TEHUANTEPEC 
THROUGH MID MORNING...THEN VARIABLE WINDS AT 5-10 KT ARE 
EXPECTED THROUGH THE MIDDLE OF THE WEEK. HOWEVER E WINDS WILL 
INCREASE TO 15-20 KT ACROSS THE PACIFIC WATERS JUST TO THE S OF 
THE GULF OF TEHUANTEPEC AS THE GRADIENT TIGHTENS DUE TO 
DEVELOPING LOW PRESSURE FURTHER W. 
  
MIXED S SWELL RESULTING IN COMBINED SEAS TO 9 FT HAS CROSSED THE 
EQUATOR BETWEEN 120W-130W...AND WILL CONTINUE TO PROPAGATE NE 
REACHING ALONG 10N BETWEEN 100W-125W TONIGHT. BY THEN THIS 
SOUTHERLY SWELL WILL MERGE WITH MIXED SWELL DEVELOPING NEAR THE 
PREVIOUSLY DESCRIBED SURFACE LOWS. THE CROSS EQUATORIAL  
SOUTHERLY SWELL SHOULD REACH THE COAST OF CENTRAL AMERICA 
BETWEEN 97W-105W LATE MON...THEN BE REINFORCED BY NEW S SWELL E 
OF THE DEVELOPING LOW...WITH THE COMBINED SWELL MOVING INTO THE 
SOUTHERN GULF OF CALIFORNIA ON TUE NIGHT...AND PROPAGATING N 
ALONG THE WESTERN SHORE OF THE BAJA PENINSULA REACHING ALONG 30N 
ON WED NIGHT. 
 
$$ 
NELSON