000
AXPZ20 KNHC 220907
TWDEP 

TROPICAL WEATHER DISCUSSION
NWS TPC/NATIONAL HURRICANE CENTER MIAMI FL
1005 UTC MON SEP 22 2008

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

BASED ON 0600 UTC SURFACE ANALYSIS AND SATELLITE IMAGERY THROUGH 
0845 UTC.

...SPECIAL FEATURES...
A BROAD AREA OF LOW PRESSURE IS LOCATED ABOUT 150-200 NM SSE OF 
MANZANILLO MEXICO NEAR 16N104W...ANALYZED 1008 MB. THIS LOW HAS 
BEEN CHALLENGING TO TRACK OVER THE PAST COUPLE OF DAYS AND A 
PORTION OF THE FEATURE HAS BEEN LEFT BEHIND IN THE GULF OF 
TEHUANTEPEC...MORE ON THAT IN THE DISCUSSION SECTION BELOW. 
CURRENTLY...THIS BROAD LOW IS A LITTLE EASIER TO LOCATE AS 
CONVECTION HAS TAKEN SLIGHTLY MORE SHAPE INTO A CURVED BAND OVER 
THE WRN SEMICIRCLE. HOWEVER...THE BAND IS QUITE A DISTANCE FROM 
THE LOW-LEVEL CENTER AND ITS ASSOCIATED CONVECTION IS 
DISORGANIZED. SOME DEVELOPMENT OF THIS SYSTEM REMAINS POSSIBLE 
OVER THE NEXT COUPLE OF DAYS.

...TROPICAL WAVES...
TROPICAL WAVE IS ALONG 89W N OF 09N MOVING W ABOUT 10 KT. ONLY 
SLIGHT LOW-MID LEVEL CYCLONIC TURNING IS APPARENT ON SHORTWAVE 
IR IMAGES NEAR THE BASE OF THE WAVE. A LARGE BLOW-UP OF 
SCATTERED MODERATE TO STRONG CONVECTION...ENHANCED BY A 
DIFFLUENT PATTERN ALOFT...IS NOTED WITHIN 180 NM EITHER SIDE OF 
THE AXIS OVER THE PAC WATERS AND EL SALVADOR. THIS 
CONVECTIVE CLUSTER IS MOVING SW STEERED BY STRONG NE UPPER FLOW. 

TROPICAL WAVE IS ALONG 104W/105W FROM 06N TO 14N MOVING W 10 KT. 
THIS WAVE LIKELY HELP SPAWN THE SPECIAL FEATURE. THE WAVE IS NOW 
EMBEDDED IN WLY FLOW...AND LITTLE SIGNATURE IS EVIDENT IN 
SATELLITE/SCATTEROMETER DATA.

TROPICAL WAVE PREVIOUSLY ALONG 121W HAS BEEN DROPPED FROM THE 
SFC ANALYSIS AS THE AREA OF DISTURBED WEATHER HAS BEEN 
STATIONARY FOR DAYS AND NO LONGER APPEARS TO BE PURELY A 
TROPICAL WAVE. A SFC LOW IS ANALYZED IN ITS PLACE...WHICH SEEMS 
TO BE A BETTER REPRESENTATION. 

...ITCZ...

ITCZ AXIS IS CENTERED ALONG 09N79W TO 06N90W TO 09N100W TO 
08N110W TO 10N120W TO 08N140W. SCATTERED MODERATE CONVECTION IS 
FROM 03N TO 06N E OF 82W...WITHIN 120 NM OF THE AXIS BETWEEN 89W 
AND 96W...AND WITHIN 90 NM N AND 180 NM S OF THE AXIS W OF 136W. 

...DISCUSSION...

W OF 110W...
MID TO UPPER RIDGING CENTERED NEAR 19N132W AND ASSOCIATED 
ABUNDANT DRY STABLE AIR DOMINATES THE PATTERN ALOFT. THE 
ATMOSPHERE IS MOST STABLE OVER THE NE AND NW WATERS WHERE UPPER 
CONFLUENCE IS NOTED DUE TO A PAIR OF TROUGHS N AND W OF THE 
ZONE. IN THE LOWER LEVELS...THE TIGHTENED PRESSURE GRADIENT NEAR 
THE BAJA COAST IS PRODUCING N TO NW 20 KT WINDS N OF 24N  
WITHIN 300 NM OFF THE COAST...AS REVEALED BY SCATTEROMETER 
PASSES AND A COUPLE OF SHIP OBS. SIMILAR MAGNITUDE NE TRADES ARE 
OCCURRING OVER THE FAR W WATERS FROM 12N-22N W OF 134W ENHANCED 
BY A WEAK LOW-LEVEL TROUGH ALONG 142W. SW SWELL WILL BUILD SEAS 
TO 9 FT OVER THE NEXT 36-48 HOURS S OF 10N E OF 130W.

E OF 110W...
AN AREA OF LOW PRESSURE FORMED JUST SSW OF THE GULF OF 
TEHUANTEPEC NEAR 15N96W...LIKELY SPAWNED BY THE LARGE 
GYRE/TROUGH THAT HAS BEEN SLOW MOVING IN THIS AREA OVER THE PAST 
COUPLE OF DAYS. CONVECTION HAS INCREASED NEAR THIS SMALL 
CIRCULATION EXTENDING WITHIN 180 NM N AND W OF THE CENTER. AN 
UPPER HIGH CENTERED OVER SOUTHERN MEXICO IS PRODUCING STRONG 
NE/E WINDS OVER THIS SMALL SYSTEM...SO ANY DEVELOPMENT IS 
EXPECTED TO BE SLOW TO OCCUR. LATEST SCATTEROMETER DATA SUGGESTS 
LITTLE SIGNIFICANT SFC WINDS S OF THE CENTER (THE N SIDE WAS NOT 
WELL SAMPLED). ELSEWHERE...WATER VAPOR IMAGERY SHOWS ABUNDANT 
MOISTURE BUT THE SIGNIFICANT CONVECTION IS NEAR THE LOW PRES 
SYSTEMS AND TROPICAL WAVE MENTIONED ABOVE.

$$
CANGIALOSI