000
AXPZ20 KNHC 222132
TWDEP 

TROPICAL WEATHER DISCUSSION
NWS TPC/NATIONAL HURRICANE CENTER MIAMI FL
2205 UTC SAT AUG 22 2009

TROPICAL WEATHER DISCUSSION FOR THE EASTERN PACIFIC OCEAN FROM 
THE EQUATOR TO 32N...EAST OF 140W. 

BASED ON 1800 UTC SURFACE ANALYSIS AND SATELLITE IMAGERY THROUGH 
2115 UTC.

...SPECIAL FEATURE...

TROPICAL DEPRESSION ELEVEN-E HAS BEEN UPGRADED TO TROPICAL STORM 
HILDA. HILDA WAS LOCATED NEAR 13.6N 137.7W OR ABOUT 1100 NM...
1970 KM...EAST-SOUTHEAST OF HILO HAWAII AT 22/2100 UTC. HILDA WAS
MOVING W OR 275 DEG AT 9 KT WITH MAXIMUM SUSTAINED WINDS OF 35 
KT WITH GUSTS TO 45 KT. THE ESTIMATED MINIMUM CENTRAL PRESSURE 
WAS 1006 MB. SCATTERED STRONG CONVECTION WAS CONFINED TO WITHIN 
120 NM IN THE SW SEMICIRCLE AND SATELLITE IMAGERY WITHIN THE 
PAST HOUR INDICATED THE LOW LEVEL CENTER IS BECOMING EXPOSED FOR 
THE TIME BEING DUE TO MODERATE EASTERLY SHEAR. THIS SHEAR IS 
EXPECTED TO CONTINUE OVER THE NEXT DAY OR SO WHICH IS EXPECTED 
TO LIMIT FURTHER DEVELOPMENT. THIS SYSTEM IS EXPECTED TO CROSS 
INTO THE CENTRAL PACIFIC HURRICANE CENTER OF RESPONSIBILITY 
WITHIN 24 HOURS. ADDITIONAL INFORMATION ON TROPICAL STORM HILDA 
CAN BE FOUND UNDER AWIPS/WMO HEADERS MIATCPEP1/WTPZ31 KNHC.

...TROPICAL WAVES...

TROPICAL WAVE IS ALONG 108W FROM 08N TO 20N MOVING W AT 17 KT 
OVER THE PAST 24 HOURS. VISIBLE SATELLITE IMAGERY DURING THE DAY 
TODAY SHOWED AN IMPROVED AREA OF LOW TO MID-LEVEL CYCLONIC 
TURNING WITH EVIDENCE OF A CIRCULATION CENTER ALONG THE AXIS 
NEAR 14N. SCATTERED TO NUMEROUS STRONG CONVECTION WAS NOTED 
90-120 NM EITHER SIDE OF THE WAVE AXIS FROM 11N TO 15N. 
SCATTERED MODERATE CONVECTION WAS NOTED ELSEWHERE WITHIN 180 NM 
W OF THE WAVE AXIS FROM 15N TO 20N. SOME SLOW DEVELOPMENT OF 
THIS SYSTEM IS POSSIBLE OVER THE NEXT COUPLE OF DAYS.

TROPICAL WAVE IS ALONG 124W FROM 08N TO 17N MOVING W 15 KT OVER 
THE PAST 24 HOURS. VISIBLE SATELLITE ALSO INDICATED SOME 
CYCLONIC TURNING ALONG THE WAVE AXIS WITHIN AN AREA OF  
SCATTERED MODERATE ISOLATED STRONG CONVECTION FROM 11N TO 15N
WITHIN 240 NM E OF THE WAVE AXIS.

...ITCZ...
ITCZ AXIS IS CENTERED ALONG 07N77W TO 13N110W TO 11N135W TO 
09N140W. SCATTERED MODERATE ISOLATED STRONG WITHIN 60 NM OF 
13N101.5W. SCATTERED MODERATE TO STRONG WITHIN 120 NM OF 
12N108W. SCATTERED MODERATE TO STRONG WITHIN 100 NM OF 13N114W.

...DISCUSSION...

N OF 20N...
A FAIRLY COMPLEX MID-UPPER PATTERN REMAINS IN PLACE ACROSS THE 
SUBTROPICS. A LARGE UPPER HIGH IS ALONG THE W COAST OF MEXICO 
NEAR 23N106W...AN ELONGATED UPPER LOW OFF THE NRN BAJA COAST 
NEAR 28N123W...ANOTHER UPPER HIGH NEAR 23N135W...AND ANOTHER 
UPPER LOW WEST OF THE AREA NEAR 23N146W. WHILE THE PATTERN IS 
AMPLIFIED...THE ONLY SENSIBLE WEATHER IS NEAR MEXICO WHERE UPPER 
DIFFLUENCE AND OROGRAPHIC LIFT ALONG THE SIERRA MADRE OCCIDENTAL 
IS PRODUCING WIDELY SCATTERED SHOWERS AND TSTMS ALONG THE 
MOUNTAIN RANGE. A WEAK LOW LEVEL TROUGH ASSOCIATED WITH THE 
UPPER LOW OFF THE NRN BAJA COAST...HAS WEAKENED THE SURFACE 
RIDGE AND HENCE THE TRADES. THIS TROUGH WILL PERSIST FOR THE 
NEXT COUPLE OF DAYS ALLOWING WINDS TO BE MAINLY LESS THAN 20 
KT...EXCEPT FOR OVER THE FAR NW CORNER. A MIX OF N AND S SWELL 
WILL ELEVATE SEAS TO 6 TO 8 FT ACROSS MUCH OF THE AREA SUN AND 
MON.

S OF 20N...
VERY DIFFLUENT NE MID-UPPER FLOW AND DEEP MOIST ENVIRONMENT IS 
PRESENT ACROSS THE TROPICS. DIFFLUENT FLOW WAS MOST PRONOUNCED 
IN THE VICINITY OF THE TROPICAL WAVE ALONG 108W AND WAS AIDING 
IN MAINTAINING THE DEEP CONVECTION ALONG THE WAVE AXIS. SEE 
ABOVE FOR MORE DETAILS. LONG PERIOD...14-17 SECOND...S TO SW 
SWELL IS PROPAGATING ACROSS MUCH OF THE AREA AND WILL CONTINUE 
FOR THE NEXT COUPLE OF DAYS. 
  
$$
COBB