000
AXPZ20 KNHC 031009
TWDEP 

TROPICAL WEATHER DISCUSSION 
NWS TPC/NATIONAL HURRICANE CENTER MIAMI FL
1005 UTC SAT OCT 03 2009

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 
0915 UTC.

...SPECIAL FEATURE...

NEW DOWNGRADED TROPICAL DEPRESSION OLAF WAS CENTERED NEAR 24.1N 
117.2W AT 03/0900 UTC OR ABOUT 405 NM...750 KM...WEST OF THE 
SOUTHERN TIP OF BAJA CALIFORNIA...MOVING N OR 010 DEG AT 3 KT. 
MAXIMUM SUSTAINED WIND SPEED WAS 30 KT WITH GUSTS TO 40 KT. 
ESTIMATED MINIMUM CENTRAL PRESSURE IS 1005 MB. SOUTHERLY SHEAR 
OF NEAR 25 KT CONTINUES TO TAKE ITS TOLL ON OLAF WITH THE MID 
LEVEL CIRCULATION AND DEEP CONVECTION 90-120 NM OFF TO THE NE OF 
THE LOW LEVEL CENTER. RECENT MICROWAVE PASSES HAVE BEEN VERY 
HELPFUL IN LOCATING THE EXPOSED LOW LEVEL CENTER...AND THE 
OFFICIAL CENTER OF OLAF HAS BEEN RELOCATED...AGAIN...TO THE SW 
OF OUR PREVIOUS POSITIONS. THE SHEAR IS FORECAST TO INCREASE 
FURTHER AND THIS COMBINED WITH A TRACK TOWARD BAJA CALIFORNIA 
OVER COOLER WATERS SHOULD RESULT IN THE DISSIPATION OF THE 
REMNANT LOW WITHIN THE NEXT 36 TO 48 HOURS. ADDITIONAL 
INFORMATION CAN BE FOUND  UNDER AWIPS/WMO HEADERS 
MIATCMEP3/WTPZ23 KNHC.

...ITCZ...

AXIS WAS CENTERED ALONG 09N78W TO 07N89W TO 08N108W TO 11N115W 
WHERE IT BECOMES DISCONTINUED. ITCZ RESUMES AT 16N123W TO 
11N133W TO 10N140W. SCATTERED MODERATE WITHIN 120 NM S OF THE 
AXIS E OF 88W. SCATTERED MODERATE WITHIN 90 NM N AND 120 NM S OF 
ITCZ AXIS W OF 130W. 

...DISCUSSION...

AN OMEGA BLOCKING PATTERN PERSISTS ACROSS THE SUBTROPICS BETWEEN 
THE E COAST OF THE U.S. AND 160W. AN AMPLIFIED POSITIVELY TILTED 
UPPER PATTERN REMAINS IN PLACE S OF 38N WITH A SHEAR AXIS 
EXTENDING FROM A S/W TROUGH MOVING INTO THE W COAST OF THE U.S. 
AND SWEEPING ACROSS CALIFORNIA... SOUTHWESTWARD THROUGH 31N127W 
TO A BROAD AND QUASISTATIONARY CYCLONIC CIRCULATION JUST W OF 
THE AREA NEAR 25N144W. THE BASE OF THIS TROUGH EXTENDED S TO 
NEAR 16N147W...WITH BROAD CYCLONIC CURVATURE OCCURRING BETWEEN 
136W AND 152. SATELLITE DERIVED WINDS INDICATED A 60-80 KT JET 
LIFTING OUT OF THE E SIDE OF THE BROAD TROUGH AND INTO THE BASE 
OF THE S/W MOVING ACROSS SRN CALIFORNIA. THIS JET WAS ADVECTING 
SHEARED UPPER LEVEL MOISTURE AND OUTFLOW FROM ITCZ CONVECTION W 
OF 130W AND FROM OLAF...SPREADING IT NORTHEASTWARD OVER MEXICO 
AND INTO THE SW CONUS. MODERATE TO STRONG SUBSIDENCE WITH DRY 
STABLE AIR IN THE MIDDLE AND UPPER LEVELS OF THE ATMOSPHERE WAS 
NOTED WITH AND BEHIND THE S/W MOVING ACROSS SRN CALIFORNIA...AND 
ALSO THROUGH THE BASE OF THE BROAD TROUGH ALONG 144W. 
DOWNSTREAM...A BROAD UPPER LEVEL ANTICYCLONIC CIRCULATION WAS 
CENTERED MEXICO NEAR 22N101W...WITH A BROAD AND RELATIVELY FLAT 
RIDGE TO THE N FROM THE NORTHERN COAST OF THE BAJA PENINSULA 
INTO SW TEXAS. OLAF REMAINS SITUATED IN THE FAR WESTERN 
PERIPHERY OF THIS ANTICYCLONE AND CONTINUES TO ENDURE SSW 
SHEAR. 

A MID TO UPPER LEVEL CYCLONE WAS STRADDLING THE EQUATOR ALONG 
116W WITH TROUGH EXTENDING NW TO 12N122W. DRY AND SUBSIDENT AIR 
E OF THIS TROUGH WAS S OF 07N AND E OF 110W...WHILE TO THE W OF 
THE TROUGH AND W OF 128W...UPPER DIVERGENCE WAS MAINTAINING 
ACTIVE CONVECTION ALONG THE ITCZ. 

DOWNSTREAM OF THE UPPER RIDGE...NLY FLOW ALOFT WAS SPILLING INTO 
THE N SIDE OF A TUTT AXIS ALONG 15N AND ACROSS CENTRAL 
AMERICA...THAT EXTENDING INTO A TUTT LOW CENTERED ACROSS 
JAMAICA. THIS WAS PRODUCING SUBSIDENT CONDITIONS ACROSS MUCH OF 
CENTRAL AMERICA FROM 14N TO 18N...WHILE RELATED CONVERGENCE 
ALOFT WAS OCCURRING ALONG AND OFFSHORE OF THE W COAST OF MEXICO 
S OF 20N. 

AT THE SURFACE...
STRONG RIDGE OF HIGH PRES EXTENDED SE FROM A 1034 MB HIGH NEAR 
39N146W AND COVERED THE DISCUSSION AREA N OF 18N W OF 122W... 
WHERE BROKEN TO LOCALLY OVERCAST STRATOCUMULUS PREVAILED. THE 
RIDGE COMBINED WITH THE LOWER PRESSURES IN THE TROPICS AND W OF 
TROPICAL DEPRESSION OLAF AND CONTINUED TO RESULT IN A LARGE AREA 
OF NE TRADES OF 20-25 KT NW OF A LINE FROM 30N122W TO 20N123W TO 
13N140W WITH CONFUSED SEAS 8 TO 11 FT IN A BROAD MIX OF SWELL. 
THESE WINDS ARE FORECAST TO DIMINISH IN ABOUT 48 HOURS AS A 
WEAKENING FRONTAL BOUNDARY DROPS S TO ALONG THE FAR NRN PORTION 
AND WILL BREAK DOWN THE RIDGE ENOUGH TO LESSEN THE SUPPORTING 
PRESSURE GRADIENT. SWELLS THROUGHOUT THIS AREA WILL GRADUALLY 
SUBSIDE OVER MUCH OF THE WRN PORTION BUT REMAIN UP TO 11 FT OVER 
THE WRN PORTION WITH PERIODS OF 9-11 SEC.

OVER THE SRN PORTION OF THE AREA SEAS OF 8 TO 10 FT IN SLY SWELL
DUE TO LONG PERIOD SRN HEMISPHERIC SWELLS FROM OVER THE PAST 
SEVERAL DAYS SHOULD SLOWLY SUBSIDE DURING THE NEXT 2 TO 3 DAYS 
AS ASSOCIATED STRONG SRN HEMISPHERIC FRONTAL SYSTEMS PROGRESS 
SWD.

$$
STRIPLING