000
AXPZ20 KNHC 141554
TWDEP 

TROPICAL WEATHER DISCUSSION                                      
NWS NATIONAL HURRICANE CENTER MIAMI FL                           
1605 UTC SUN JUL 14 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 
1430 UTC.

...TROPICAL WAVES...                                          
EPAC TROPICAL WAVE CONTINUES TO MOVE SLOWLY W ACROSS E PORTIONS 
OF THE BASIN...AND CURRENTLY EXTENDS FROM 09N ALONG 94W-95W 
THROUGH THE GULF OF TEHUANTEPEC AND SOUTHERN MEXICO AND BARELY 
INTO FAR S CENTRAL PORTIONS OF THE BAY OF CAMPECHE. THE WAVE IS 
MOVING W AT 5-10 KT AND HAS CONTINUED TO FLARE UP CONVECTIVELY 
OVERNIGHT ACROSS COASTAL MEXICO. SCATTERED MODERATE TO STRONG 
CONVECTION OCCURRING N OF 13N BETWEEN 93W AND 98W THIS MORNING 
WAS WEAKENING AND SHIFTING GENERALLY SW.  

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

THE MONSOON TROUGH EXTENDS FROM COLOMBIA NEAR 08N74W TO 10N86W  
TO 12N106W TO 12N124W...WHERE IT TRANSITIONS TO ITCZ... 
CONTINUING ON TO 10.5N133W TO BEYOND 07.5N140W. ISOLATED TO 
SCATTERED MODERATE CONVECTION NOTED WITHIN 90 NM N AND 180 NM S 
OF TROUGH AXIS. SCATTERED MODERATE TO STRONG CONVECTION NOTED 
WITHIN 180 NM N AND 90 NM S OF ITCZ AXIS.  

...DISCUSSION... 

MIDDLE TO UPPER LEVEL CONDITIONS REMAIN GENERALLY DRY AND STABLE 
ACROSS MUCH OF THE DISCUSSION AREA THIS MORNING...WITH 
CONVECTION LARGELY CONFINED TO THE MOIST ZONE NEAR THE MONSOON 
TROUGH AND ITCZ...AND NOCTURNAL CONVECTION SHIFTING OFFSHORE OF 
LAND. A STRONG COMPLEX BLOCKING PATTERN PREVAIL ACROSS N 
AMERICA...THE GULF OF MEXICO...AND THE N ATLC W OF 50W TODAY. 

A DEEP LAYERED CYCLONE PREVAILS ACROSS THE N CENTRAL PACIFIC 
THIS MORNING...WELL N OF THE HAWAIIAN ISLANDS...AND IS PRODUCING 
SW TO W FLOW ALOFT ACROSS N AND NW PORTIONS OF THE DISCUSSION 
AREA. A BLOCKING RIDGE ACROSS THE SE U.S. AND A SECOND MIDDLE TO 
UPPER LEVEL ANTICYCLONE CENTERED NEAR 17N132W ARE COMBINING TO 
DIVERT THIS UPPER FLOW N-NE INTO CALIFORNIA AND THE PACIFIC NW 
OF THE U.S. LOCATED BETWEEN THE TWO ANTICYCLONES IS AN 
ELONGATING UPPER LOW CENTERED NEAR 20N115W...WITH TROUGH AXIS 
EXTENDING N TO NEAR 28N118W...AND SHIFTING W AND SLOWLY AWAY 
FROM BAJA CALIFORNIA. ANOTHER WEAK TROUGH AXIS EXTENDS FROM THIS 
UPPER LOW E-SE TO NEAR 16N101W. SELY UPPER LEVEL FLOW OCCURRING 
TO THE NE OF THIS PORTIONS OF THE LOW AND OFFSHORE OF WRN MEXICO 
HAS PRODUCED SPEED DIVERGENCE ALOFT AND AIDED IN SUSTAINING 
NOCTURNAL CONVECTION THROUGH THE MORNING HOURS ALONG THE W 
SLOPES OF THE SIERRA MADRE OCCIDENTALES. 

NARROW UPPER LEVEL RIDGING PREVAILS S OF THIS AREA...EXTENDING 
FROM AN ILL DEFINED UPPER ANTICYCLONE OVER THE GULF OF HONDURAS 
W-SW TO ANOTHER SMALL ANTICYCLONE NEAR 12N109W...THEN CONTINUES 
W-NW AND MERGES WITH RIDGING TO THE W. LLVL CONVERGENCE E OF 
120W REMAINS WEAK TODAY AND IS YIELDING ONLY MODEST CONVECTION 
ALONG THE MONSOON TROUGH THERE...WHILE STRONGER LLVL CONVERGENCE 
W OF 120W IS RESPONSIBLE FOR THE INCREASES CONVECTION DESCRIBED 
ABOVE. 
 
AT THE LOW LEVELS...STRONG 1033 MB HIGH PRES IS CENTERED WELL N 
OF THE DISCUSSION AREA NEAR 47N144W AND EXTENDS A RIDGE S AND SE 
TO NEAR 16N108W. THE RESULTANT PRES GRADIENT N OF THE ITCZ IS 
YIELDING ONLY 15-20 KT NE TRADES ACROSS W PORTIONS OF THE 
AREA...GENERALLY S OF 20N AND W OF 128W...WHERE SEAS ARE RUNNING 
5-7 FT. THE 1031 MB HIGH IS FORECAST TO SHIFT NW OVER THE NEXT 
24 HRS WHILE STRENGTHENING AND WILL PRODUCE LITTLE CHANGE IN THE 
TRADE WIND FLOW FOR THE NEXT FEW DAYS. GLOBAL MODELS ALSO 
SUGGEST THAT THE WEAK SW MONSOONAL FLOW E OF 100W WILL BEGIN TO 
INCREASE BY MID WEEK ...IN COMBINATION WITH STRENGTHENING TRADES 
ACROSS THE CARIBBEAN...AND YIELD INCREASING CONVECTION ACROSS 
CENTRAL AMERICA AND THE FAR E WATERS DURING THE MIDDLE AND 
SECOND HALF OF THE UPCOMING WEEK.

SW SOUTHERN HEMI SWELL OF SMALL TO MODERATE SIZE CONTINUES TO 
DOMINATE MARINE CONDITIONS S OF 20N...AND WILL CONTINUE TO DO SO 
FOR THE NEXT SEVERAL DAYS. A STRONG AND LARGE SW SWELL IS 
CURRENTLY MOVING THROUGH FRENCH POLYNESIA IN THE S CENTRAL 
PACIFIC AND WILL BEGIN TO CROSS THE EQUATOR AND ENTER THE LOCAL 
WATERS EARLY MONDAY...AND INCREASE SEAS TO 8 FT OR GREATER 
WITHIN A FEW DEGREES OF THE EQUATOR TUE THROUGH THU. THIS STRONG 
SW SWELL EVENT WILL HIT THE PACIFIC COASTS OF CENTRAL 
AMERICA...MEXICO... AND SOUTHERN CALIFORNIA BY MID WEEK AND 
GENERATE VERY STRONG AND POWERFUL SURF ALONG THE COASTS. 
 
$$
STRIPLING