000
AXPZ20 KNHC 281005
TWDEP 

TROPICAL WEATHER DISCUSSION 
NWS TPC/NATIONAL HURRICANE CENTER MIAMI FL
1005 UTC WED OCT 28 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 
0900 UTC.

...ITCZ...

THE INTERTROPICAL CONVERGENCE ZONE IS CENTERED ALONG...09N76W TO 
11N89W TO 11N95W TO 14N103W TO 12N115W TO 10N127W TO 07N140W. 
SCATTERED MODERATE ISOLATED STRONG WAS WITHIN 90 NM EITHER SIDE 
OF AXIS W OF 125W. SCATTERED MODERATE TO STRONG EXTENDED FROM 
GULF OF PANAMA TO 05N83W. SCATTERED MODERATE TO STRONG WAS 
WITHIN 120 NM OF COASTLINE FROM 87W TO 102W. SCATTERED MODERATE 
TO STRONG WAS FROM 07N TO 13N BETWEEN 91W AND 105W. 

...DISCUSSION...

DEEP LAYER LONGWAVE TROUGH ACROSS N AMERICA REORGANIZING TO THE 
W ALONG ABOUT 112W AS A STRONG JET WAS DIVING SWD INTO BACKSIDE 
OF TROUGH AND ALONG W COAST OF U.S. AND THROUGH BASE OF TROUGH 
ACROSS EXTREME SRN CALIFORNIA...NRN BAJA ....NW SONORA STATE IN 
MEXICO...AND SRN ARIZONA...WITH CORE SPEEDS 80-125 KT PER 
SATELLITE DERIVED WINDS. THE REMNANTS OF THE FORMER LONGWAVE 
TROUGH HAVE BROADENED ACROSS THE AREA...AND FORMED A MID TO 
UPPER TROUGH EXTENDING FROM SRN BAJA CALIFORNIA SW TO A 
DEVELOPING AND DIGGING MID LEVEL VORT CENTER NEAR 13N131W. TO 
THE W OF THIS LONGWAVE TROUGH WAS A SHARP UPPER RIDGE EXTENDING 
FROM NEAR 32N135W NNW INTO THE FAR N PACIFIC. THE STRONG JET 
DIVING S ALONG THE W COAST OF THE U.S. HAS USHERED COOLER STABLE 
AIR INTO THE FAR EPAC E OF 130W...AND SUPPORTED A BENIGN COLD 
FRONTAL BOUNDARY SINKING S INTO N PORTIONS OF THE FORECAST AREA 
ALONG 27N AND PUSHING INTO CENTRAL BAJA. GALES BEHIND THE FRONT 
AND E OF 128W WERE OCCURRING ALONG AND WELL OFFSHORE OF THE 
CALIFORNIA COAST AND EXTENDED S TO 30N...AS VERIFIED BY 
OVERNIGHT SCATTEROMETER PASSES. ACROSS THE LOCAL WATERS N OF 
27.5N AND E OF 132W...NORTHERLY WINDS OF 25 TO 30 KT WITH GUSTS 
TO GALE FORCE WERE PREVAILING...AND WILL SINK VERY SLIGHTLY SWD 
NEXT 24 HOURS. THIS SUSTAINED NORTHERLY FLOW WILL BUILD AND 
PROPAGATE NLY WIND SWELL OF 8 TO 10 SECONDS INTO THE 
AREA...BUILDING SEAS 12 TO 18 FT N OF 22N DURING THE NEXT 24 
HOURS. SURFACE HIGH PRESSURE TO THE NW OF THE FRONT WILL EXPAND 
SLIGHTLY S AND SE OVER THE NEXT 24-48 HOURS...AND PRODUCE A 
BROAD FIELD OF 20-25 KT NELY WINDS ACROSS THE AREA FROM NEAR THE 
SRN TIP OF BAJA...SW TO THE ITCZ. FRESH NELY TRADES OF THE PAST 
FEW DAYS WERE DEPICTED OVERNIGHT BY SCATTEROMETER PASSES S OF 
20N AND W OF 130W. 8-12 FT SEAS IN THE FORM OF A BROAD MIX OF NW 
SWELLS AND N TO NE WIND SWELL WILL SPREAD S ACROSS THE WATERS N 
OF 15N AND W OF 110W BY 48 HOURS AND MAKE FOR ROUGH AND CONFUSED 
SEAS ACROSS THESE WATERS. 

ADDITIONALLY...NWLY WINDS BEHIND THE FRONT OF 20-25 KT...AND UP 
TO 30 KT N OF 29N...WILL CONTINUE TO SPREAD S THROUGH THE GULF 
OF CALIFORNIA AND GRADUALLY BUILD SEAS TO NEAR 8 FT S OF THE 
CLUSTER OF ISLANDS IN THE N PART OF THE GULF...LINGERING THROUGH 
48 HOURS. 

TO THE SOUTHEAST OF THE TROUGH AXIS...S TO SW UPPER LEVEL WINDS 
WERE SPREADING UPPER MOISTURE FROM ACTIVE ITCZ CONVECTION ACROSS 
THE FAR TROPICAL EPAC BETWEEN 90W AND 105W...NE ACROSS MEXICO 
AND THE NW GULF OF MEXICO. A MODEST AND ELONGATED LOW TO MID 
LEVEL CYCLONIC GYRE CONTINUES ACROSS THIS PORTION OF THE 
EPAC...WITH INTERMITTENT LOW LEVEL CENTERS SPINNING UP AND DOWN 
OVER THE PAST 24 HOURS. GLOBAL MODELS CONTINUE TO SUGGEST THAT 
SOME CONSOLIDATION OF THIS ELONGATED CIRCULATION COULD GRADUALLY 
LEAD TO A CYCLONE OVER THE NEXT SEVERAL DAYS...AND THIS MOIST 
AND UNSTABLE REGION IS BEING MONITORED FOR TROPICAL 
CYCLOGENESIS. 

$$
STRIPLING