000
AXPZ20 KNHC 281609
TWDEP 

TROPICAL WEATHER DISCUSSION
NWS TPC/NATIONAL HURRICANE CENTER MIAMI FL
1605 UTC SAT NOV 28 2009

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

BASED ON 1200 UTC SURFACE ANALYSIS AND SATELLITE IMAGERY THROUGH 
1415 UTC.

...ITCZ...
AXIS ANALYZED ALONG 07N77W TO 06N97W TO 07N85W TO 07N100W TO 
06N105W TO 09N119W TO 08N130W TO 08N140W.  SCATTERED MODERATE TO 
STRONG CONVECTION WAS WITHIN 90 NM S AND 120 NM N OF AXIS E OF 
103W...AND ALSO WITHIN 240 NM S AND 90 NM N OF AXIS W OF 117W.

...DISCUSSION...
MID-UPPER LEVEL TROUGH EXTENDS FROM CENTRAL TEXAS THROUGH 
CENTRAL MEXICO TO NEAR 16N112W...WITH STRONG SUBSIDENCE WITHIN 
10 DEGREES NW OF AXIS.  TROPICAL MOISTURE IS BEING ADVECTED ON E 
SIDE OF TROUGH NEWD BY A 45-65 KT W-SW JET INTO SRN MEXICO.  
UPSTREAM A BROAD RIDGE FROM 10N128W NWD IS MAINTAINING 
ANTICYCLONIC FLOW ACROSS THE REMAINDER OF THE BASIN W OF 
115W...DIVING INTO THE BACKSIDE OF TROUGH. THE TOP OF RIDGE IS 
CURRENTLY BEING FLATTENED BY DEEP LAYERED TROUGH SKIRTING N 
PORTIONS OF THE BASIN...AND SUPPORTING A WEAK COLD FRONTAL 
BOUNDARY INTO NRN BAJA CALIFORNIA...EXTENDING W-SW ACROSS NW 
PORTIONS OF THE AREA. A VERY BROAD AND FLAT TROPICAL UPPER RIDGE 
COVERS THE CARIBBEAN...NRN S AMERICA...AND THE EPAC E OF 
100W...AND WAS VENTILATING CONVECTION ALONG THE ITCZ FROM 
COLOMBIA TO 104W.
 
AT THE SURFACE...
STRONG HIGH PRES 1036 MB AT 38N134W WITH RIDGE EXTENDING 
SE...BRIDGING ACROSS THE WEAK COLD FRONT...TO 21N117W...AND 
CONTINUES TO MAINTAIN A TIGHT PRESSURE GRADIENT WITH LOW 
PRESSURE ALONG THE ITCZ...AND LOW LEVEL TROUGHING THAT IS A MID 
LEVEL REFLECTION OF THE UPPER TROUGH EXTENDING SW OUT OF CENTRAL 
MEXICO. BEHIND THE FRONT...N TO NW WINDS OF 25 TO 30 KT PREVAIL 
WITH SEAS 11 TO 15 FT IN LARGE NW SWELL.  DEEP LAYERED LOW 
PRESSURE DROPPING S INTO SRN CALIFORNIA WILL PUSH THE WEAK 
FRONTAL BOUNDARY SE ACROSS CENTRAL BAJA TO 21N128W BY 24 HOURS 
...THEN DRIFT FARTHER SE THROUGH SUN TO MAINTAIN A LONG FETCH OF 
N GALES OFF THE CALIFORNIA COAST THAT WILL CONTINUE TO SEND NLY 
SWELL INTO THE AREA FOR SEVERAL DAYS. SEAS ARE FORECAST TO PEAK 
AROUND 18 FT ALONG THE NE BORDER OF THE AREA OVERNIGHT SAT. 
FARTHER E...WEAK LOW PRES 1008 MB WAS ALONG THE ITCZ NEAR 
07N99W...INDUCING SCATTERED MODERATE TO STRONG CONVECTION AND 
20-25 KT WINDS.    

...GAP WINDS...
HIGH PRES IN THE GULF OF MEXICO HAS WEAKENED TO 1020 MB AND 
DRIFTED E...AND IS GRADUALLY VEERING WINDS...WHICH WILL CUT OFF 
NLY AIR FLOW ACROSS THE ISTHMUS OF TEHUANTEPEC. GALE FORCE WINDS 
SHOULD DIMINISH TO LESS THAN GALE FORCE BEFORE 18Z AND BELOW 20 
KT WITHIN 24 HRS.

EASTERLY TRADES IN W CARIBBEAN WILL CONTINUE TO FUNNEL WINDS 
THROUGH GULF OF PAPAGAYO AND DOWNSTREAM WATERS TO NEAR 91W 
THROUGH SUN TO MAINTAIN FRESH TO STRONG BREEZE.AND SEAS OF 7 TO 
9 FT.

$$
STRIPLING