000
AXPZ20 KNHC 270301
TWDEP 

TROPICAL WEATHER DISCUSSION
NWS NATIONAL HURRICANE CENTER MIAMI FL                           
0405 UTC SAT JUL 27 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 0000 UTC SURFACE ANALYSIS AND SATELLITE IMAGERY THROUGH 
0300 UTC.

...SPECIAL FEATURES...                                   
TROPICAL STORM FLOSSIE IS CENTERED NEAR 17.0N 135.7W AT 27/0300 
UTC OR ABOUT 1115 NM E OF HILO HAWAII MOVING WNW AT 16 KT. 
ESTIMATED MINIMUM CENTRAL PRESSURE IS 999 MB. MAXIMUM SUSTAINED 
WIND SPEED IS 50 KT WITH GUSTS TO 60 KT. SCATTERED MODERATE AND 
ISOLATED STRONG CONVECTION IS WITHIN 90 NM W SEMICIRCLE. 
SCATTERED MODERATE CONVECTION IS ELSEWHERE FROM 10N TO 16N 
BETWEEN 130W AND 135W...AND FROM 16N TO 22N BETWEEN 130W AND 
137W. FLOSSIE IS FORECAST TO CROSS OVER INTO THE CENTRAL PACIFIC 
OCEAN ON SATURDAY. SEE LATEST NHC FORECAST/ADVISORY UNDER AWIPS/ 
WMO HEADERS MIATCMEP1/WTPZ21 KNHC FOR MORE DETAILS. 

...TROPICAL WAVES...                                     
TROPICAL WAVE EXTENDS FROM 12N94W TO 18N93W MOVING W AT 10 KT. 
THE WAVE COINCIDES WITH GLOBAL MODEL 700 MB TROUGHING OVER 
SOUTHERN MEXICO WITH A VORTICITY MAXIMUM IN THE VICINITY OF 
16N94W. THE WAVE WILL LIKELY ENHANCE DRAINAGE FLOW THROUGH THE 
CHIVELA PASS AND INTO THE GULF OF TEHUANTEPEC LATER TONIGHT INTO 
EARLY SATURDAY MORNING. THE NORTHERLY FLOW COULD BRIEFLY REACH 
20 KT WITH SEAS TO NEAR 8 FT. THEREAFTER...THE WAVE WILL LIKELY 
LOSE IDENTITY ACROSS SOUTHERN MEXICO BY LATE SATURDAY.
  
...INTERTROPICAL CONVERGENCE ZONE/MONSOON TROUGH...           
THE MONSOON TROUGH EXTENDS FROM 09N78W TO 10N109W TO 08N115W. 
THE INTERTROPICAL CONVERGENCE ZONE AXIS EXTENDS FROM 08N115W TO 
07N120W TO 14N129W...RESUMING NEAR 13N137W TO 09N140W. SCATTERED 
MODERATE CONVECTION IS FROM 07N TO 11N BETWEEN 84W AND 89W... 
FROM 08N TO 11N BETWEEN 91W AND 103W...FROM 07N TO 14N BETWEEN 
109W AND 113W...AND FROM 11N TO 17N BETWEEN 121W AND 127W. 
WIDELY SCATTERED MODERATE CONVECTION IS FROM 07N TO 09N W OF 
137W.

...DISCUSSION...                                              
              
WATER VAPOR IMAGERY INDICATES AN UPPER LEVEL TROUGH AXIS ENTERS 
THE FORECAST REGION NEAR 30N132W AND CONTINUES SW TO A BASE NEAR 
25N138W. MODERATE TO STRONG SUBSIDENCE AND A DRY AIR MASS 
ACCOMPANIES THIS TROUGH COVERING A LARGE PORTION OF THE NW 
CORNER OF THE DISCUSSION AREA. THIS AIRMASS WILL LIKELY AFFECT 
TROPICAL STORM FLOSSIE OVER THE NEXT FEW DAYS AND CONTRIBUTE TO 
THE WEAKENING FORECAST TREND AFTER EARLY SUNDAY AND INTO EARLY 
NEXT WEEK. FARTHER EAST...AN ANTICYCLONIC CIRCULATION IS 
CENTERED INLAND OVER NORTHWESTERN MEXICO NEAR 31N110W THAT 
DOMINATES THE FLOW OVER MUCH OF MEXICO AND THE ADJACENT COASTAL 
WATERS N OF 14N E OF 119W. EASTERLY WIND FLOW ALOFT COVERS MOST 
OF THE AREA S OF 15N E OF 120W. EMBEDDED WITHIN THIS FLOW 
ALOFT...AN INVERTED TROUGH AXIS EXTENDS FROM NE OF THE GULF OF 
TEHUANTEPEC REGION NEAR 20N90W TO NEAR 14N97W. 

THE PRESSURE GRADIENT BETWEEN FLOSSIE AND HIGH PRESSURE CENTERED 
TO THE NORTH WILL MAINTAIN A LARGE AREA OF NE TO E WINDS IN THE 
20 TO 30 KT RANGE ON THE NORTHERN PERIPHERY OF THE STORM. RECENT 
SCATTEROMETER DATA INDICATES THAT THESE WINDS ARE WITHIN 330 NM 
OF THE STORM CENTER.
 
NE TO E 15-20 KT WINDS WILL CONTINUE TO PULSE ACROSS THE GULF OF 
PAPAGAYO LATER TONIGHT INTO THE EARLY MORNING HOURS RESULTING IN 
COMBINED SEAS OF 6-8 FT IN MIXED SHORT PERIOD E SWELL AND LONG 
PERIOD SW SWELL. 

CROSS EQUATORIAL SE AND SW SWELLS RESULTING IN COMBINED SEAS TO 
9 FT CONTINUE ACROSS THE DEEP TROPICS...GENERALLY S OF 05N 
BETWEEN 107W AND 134W. THIS SWELL EVENT IS FORECAST TO PROPAGATE 
GENERALLY NORTHWARD ACROSS THE SOUTHERN WATERS DURING THE 
UPCOMING WEEKEND REACHING AS FAR N AS A LINE FROM 20N120W TO 
02N80W BY LATE SUNDAY.

$$
HUFFMAN