000
AXPZ20 KNHC 180303
TWDEP 

TROPICAL WEATHER DISCUSSION  
NWS NATIONAL HURRICANE CENTER MIAMI FL
0405 UTC THU AUG 18 2011

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 FERNANDA AT 12.6N 139.2W 997 MB AT 0300 UTC AUG 
18 MOVING W-NW OR 295 DEG AT 8 KT.  MAXIMUM SUSTAINED WIND 50 
GUSTS 60 KT.  SCATTERED MODERATE CONVECTION WITHIN 90 NM N 
SEMICIRCLE.  FERNANDA EXPECTED TO MOVE W AND FURTHER INTENSIFY 
...BUT WOULD BE W OF 140W BY THAT TIME.  REFER TO FORECAST 
ADVISORIES ISSUED UNDER WMO HEADER WTPZ21 KNHC AND AWIPS HEADER 
MIATCMEP1 FOR FURTHER DETAILS.

HURRICANE GREG AT 17.5N 108.3W 987 MB AT 0300 UTC AUG 18 MOVING 
W-NW OR 285 DEG AT 20 KT.  MAXIMUM SUSTAINED WINDS 65 GUSTS 80 
KT.  NUMEROUS STRONG CONVECTION FROM 14N TO 20N BETWEEN 105W AND 
112W.  GREG SHOULD CONTINUE TO INTENSIFY OVER WARM WATERS S OF 
MEXICO DURING THE NEXT TWO DAYS. REFER TO FORECAST ADVISORIES 
ISSUED UNDER WMO HEADER WTPZ22 KNHC AND AWIPS HEADER MIATCMEP2 
FOR FURTHER DETAILS.

...ITCZ/MONSOON TROUGH...
MONSOON TROUGH FROM 10N85W TO 13N94W...THEN RESUMES FROM 16N112W 
TO LOW PRES 1008 MB AT 14N116W TO 10N124W TO 13N130W.  SCATTERED 
MODERATE ISOLATED STRONG WITHIN 210 NM S OF AXIS FROM 117W TO 
131W.

...DISCUSSION...
LARGE UPPER LEVEL RIDGE CENTERED OVER EASTERN NEW MEXICO 
MAINTAIN STEADY MOIST ANTICYCLONIC FLOW ACROSS MOST OF BASIN E 
OF 125W.  SHARP UPPER LEVEL TROUGH FROM 32N136W TO 20N140W DRIES 
OUT PORTION N OF 15N W OF 125W.  WITH THE EXCEPTION OF LIGHTER 
WIND OVER GREG...MODERATE NE WINDS CAUSE ENOUGH SHEAR TO CURTAIL 
DEVELOPMENT OF 1008 MB LOW PRES AT 14N119W.  LOW PRES NOW  
EXPECTED TO DISSIPATE BY LATE THU...BUT NOT WITHOUT CAUSING 
FRESH SW WINDS AND UP TO 11 FT SEAS.

FRESH NE WIND FLOW OVER GULF OF MEXICO SEEP ACROSS CHIVELAS PASS 
INTO GULF OF TEHUANTEPEC ON A SHORT-LIVED FRESH N WIND ALTHOUGH 
SEAS REMAIN BELOW 8 FT.  SOURCE OF WINDS IN GULF OF MEXICO VEERS 
TONIGHT EFFECTIVELY SHUTTING OFF WINDS.  SIMILARLY GULF OF 
PAPAGAYO TAKES WINDS FROM WESTERN CARIBBEAN AS HEALTHY TROPICAL 
WAVE FORCES WINDS ACROSS NICARAGUA AND COAST RICA.  EVENT 
DWINDLES AS WAVE CROSSES INTO E PAC FRI.

CROSS EQUATORIAL SW SWELL TRAIN UP TO 8 FT SPREADS INTO E PAC 
TO 14N FROM 100W TO 114W. 

$$
WALLY BARNES