000
AXPZ20 KNHC 040326
TWDEP 

TROPICAL WEATHER DISCUSSION
NWS TPC/NATIONAL HURRICANE CENTER MIAMI FL
0405 UTC FRI DEC 04 2009

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

BASED ON 0000 UTC SURFACE ANALYSIS AND SATELLITE IMAGERY THROUGH 
0300 UTC.

...ITCZ...
THE ITCZ AXIS IS ALONG 05N77W TO 05N88W TO 09N100W TO 08N106W TO 
10N120W TO 05N140W. SCATTERED MODERATE ISOLATED STRONG 
CONVECTION WITHIN 60 NM EITHER SIDE OF AXIS BETWEEN 100W AND 
104W. SCATTERED MODERATE ISOLATED STRONG CONVECTION WITHIN 130 
NM EITHER SIDE OF AXIS BETWEEN 118W AND 123W. SCATTERED MODERATE 
ISOLATED STRONG CONVECTION WITHIN 250 NM N AND 170 NM S OF AXIS 
BETWEEN 125W AND 135W.

...DISCUSSION...
SHORTWAVE TROUGH HAS MOVED FURTHER INTO THE N PORTION OF THE 
FORECAST AREA...WITH AXIS CURRENTLY NEAR 139W. IN RESPONSE...THE 
SURFACE HIGH PRESSURE THAT PREVAILED ACROSS THE N PORTION OF THE 
AREA HAS FURTHER WEAKENED...WITH JUST A RIDGE OF HIGH PRESSURE 
LEFT. AS A RESULT...THE COVERAGE OF FRESH TRADES HAS DECREASED 
ACROSS THE W PORTION OF THE AREA. 

NORTHERLY FLOW IS EXPECTED TO INCREASE TO 20-25 KT OVER THE GULF 
OF CALIFORNIA N OF 27N TONIGHT AS HIGH PRES BUILDS OVER THE 
GREAT BASIN.

GAP WINDS...
EXPECT ELY WINDS AT OR NEAR 20 KT TO PULSE UP AND DOWN THROUGH 
THE GULF OF PAPAGAYO AND THEN DOWNSTREAM TO NEAR 89W DURING THE 
NEXT FEW DAYS. THESE WINDS WILL BE STRONGEST IN THE MORNING 
HOURS WITH THE AID OF DRAINAGE FLOW. ALSO...A GALE FORCE WIND 
EVENT IS EXPECTED TO DEVELOP ACROSS THE GULF OF TEHUANTEPEC IN 
ABOUT 42 HOURS...SAT AFTERNOON...AS A STRONG HIGH PRES BUILDS 
SWD INTO THE FAR WRN GULF OF MEXICO AND ALONG THE EASTERN SLOPES 
OF THE SIERRA MADRE MOUNTAINS OF MEXICO IN THE WAKE OF A STRONG 
COLD FRONT FORECAST TO MOVE ACROSS THE ENTIRE GULF REGION ON 
SAT. CURRENT GUIDANCE INDICATES THAT THIS MAY BE A SHORT LIVED 
EVENT WITH HIGH PRESSURE RAPIDLY SHIFTING EWD ON SAT 
NIGHT...TURNING FLOW ANTICYCLONIC OVER THE GULF OF MEXICO. 

OF NOTE...THE MONTHLY DISTRIBUTION OF TEHUANTEPEC EVENTS SHOWS 
THAT THE LARGEST NUMBER OF GALE FORCE EVENTS OCCURS IN DECEMBER. 
STORM-FORCE EVENTS OCCUR MOST OFTEN IN JANUARY. GALE FORCE 
EVENTS HAVE OCCURRED AS EARLY AS SEPTEMBER AND AS LATE AS MAY. 
HOWEVER...ABOUT 84% OF ALL EVENTS TAKE PLACE BETWEEN NOVEMBER 
AND MARCH. 

$$

AL