000
AXPZ20 KNHC 042146
TWDEP 

TROPICAL WEATHER DISCUSSION
NWS TPC/NATIONAL HURRICANE CENTER MIAMI FL
2205 UTC FRI DEC 04 2009

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

BASED ON 1800 UTC SURFACE ANALYSIS AND SATELLITE IMAGERY THROUGH 
2100 UTC.

...ITCZ...
AXIS ANALYZED ALONG 05N77W TO 06.5N89W TO 05N98W TO 08N105W TO 
06N113W TO 09N125W TO 06N140W. SCATTERED MODERATE ISOLATED 
STRONG CONVECTION WITHIN 180 NM S OF AXIS E OF 83W. SCATTERED 
MODERATE ISOLATED STRONG CONVECTION WITHIN 90 NM EITHER SIDE OF 
AXIS FROM 103W TO 108W. SCATTERED MODERATE CONVECTION WITHIN 120 
NM N OF AXIS AND 30 NM S OF AXIS BETWEEN 118W TO 123W. SCATTERED 
MODERATE CONVECTION WITHIN 160 NM S OF AXIS W OF 136W. 

...DISCUSSION...
WITH THE PASSAGE OF A SHORTWAVE TROUGH ACROSS THE N PORTION OF 
THE FORECAST AREA...ONLY RIDGING REMAINS OVER THE N PORTION OF 
THE AREA. WITH A PROGRESSIVE UPPER PATTERN...THE SHORTWAVE 
TROUGH OVER THE N PORTION OF THE AREA...CURRENTLY NEAR 
125W...WILL SHIFT OVER THE BAJA PENINSULA BY SAT NIGHT AS 
ANOTHER TROUGH...CURRENTLY JUST E OF HAWAII...MOVES INTO THE W 
PORTION OF THE AREA. THIS WILL MAINTAIN WEAK RIDGING ACROSS THE 
N PORTION OF THE AREA. AS A RESULT...THE COVERAGE OF FRESH 
TRADES WILL DECREASE IN EXTENT THROUGH THE WEEKEND.

STRONG HIGH PRESSURE OVER THE GREAT BASIN REGION HAS RESULTED IN 
20 TO 25 KT WINDS OVER THE GULF OF CALIFORNIA N OF 28N. THE HIGH 
WILL SHIFT EASTWARD OVERNIGHT...AND WINDS WILL DIMINISH BELOW 
20 KT BY SAT AFTERNOON. 

GAP WINDS...
NORTHERLY WINDS IN THE 20 TO 30 KT RANGE CONTINUE TO FUNNEL 
THROUGH THE GULF OF TEHUANTEPEC AND DOWNSTREAM WATERS WITH 
NORTHERLY FLOW IN PLACE N OF THE ISTHMUS OF TEHUANTEPEC BEHIND
A COLD FRONT THAT PREVIOUSLY MOVED THROUGH THE GULF OF MEXICO 
WATERS. WINDS WILL REACH GALE FORCE SAT MORNING AS A STRONGER 
COLD FRONT MOVES ACROSS THE GULF OF MEXICO. THE GALE FORCE WINDS 
WILL ONLY PERSIST FOR A SHORT DURATION...AND WILL DIMINISH BELOW 
GALE FORCE BY LATE SAT NIGHT AS SURFACE HIGH PRESSURE SHIFTS 
ACROSS THE N GULF OF MEXICO...AND VEERS WINDS TO THE SE TO E 
OVER THE BAY OF CAMPECHE.

EASTERLY TRADES IN THE SW CARIBBEAN SEA WILL CONTINUE TO FUNNEL 
THROUGH THE GULF OF PAPAGAYO AND DOWNSTREAM TO NEAR 89W DURING 
THE NEXT FEW DAYS. THE WINDS WILL BE STRONGEST IN THE MORNING 
HOURS WITH THE AID OF DRAINAGE FLOW. 

$$
AL