000
AXPZ20 KNHC 152203
TWDEP 

TROPICAL WEATHER DISCUSSION
NWS TPC/NATIONAL HURRICANE CENTER MIAMI FL
2205 UTC TUE DEC 15 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...
THE INTERTROPICAL CONVERGENCE ZONE AXIS EXTENDS ALONG 04N77W TO 
05N85W TO 06N120W TO 04N132W TO 05N140W. SCATTERED MODERATE 
CONVECTION CAN BE FOUND WITHIN 150 NM N OF THE ITCZ AXIS E OF 
90W WHILE SCATTERED MODERATE WITH ISOLATED STRONG CONVECTION 
LIES WITHIN 180 NM N AND 30 NM S OF THE ITCZ AXIS BETWEEN 133W 
AND 138W.

...DISCUSSION...
AN AMPLIFIED NORTHERN STREAM PATTERN IS IN PLACE WITH A SHARP 
UPPER TROUGH FOUND FROM WEST TEXAS THROUGH SOUTHERN BAJA 
CALIFORNIA AND TO 11N118W. A 120 KT JET LIES ON THE LEADING EDGE 
OF THIS TROUGH. A SURFACE TROUGH FROM 12N105W TO 04N107W WITH 
SCATTERED SHOWERS WITHIN 180 NM W AND 90 NM E OF ITS AXIS CAN BE 
FOUND NEAR THE LEADING EDGE OF THIS SOUTHWESTERLY JET...BUT 
THERE IS A DECIDED LACK OF DEEP CONVECTION HERE DESPITE THE 
DIFFLUENCE ALOFT. TOTAL PRECIPITABLE WATER SATELLITE IMAGERY 
SHOWS THAT THE LOW TO MID LEVEL MOISTURE IS POOLED A FEW DEGREES 
TO THE E OF THIS TROUGH AND NEAR ANOTHER SURFACE TROUGH FROM 
12N127W TO 04N128W. AS MENTIONED IN THE ITCZ SECTION...SCATTERED 
MODERATE WITH ISOLATED STRONG CONVECTION CAN BE FOUND NEAR THE 
ITCZ AXIS W OF 133W ASSOCIATED WITH THIS SECOND TROUGH. THIS 
AREA LIES UNDER AN UPPER ANTICYCLONE AT 09N139W. THE DIFFLUENCE 
DUE TO THE ANTICYCLONE IS LIFTING THE POOLED MOSITURE AND 
ALLOWING FOR CONVECTION. AT THE SURFACE...A MODERATE PRES 
GRADIENT CAN BE FOUND BETWEEN 1025 MB HIGH PRES NEAR 33N121W AND 
THIS WESTERN TROUGH...WITH 20 TO 25 KT TRADE WINDS FOUND IN MUCH 
OF THE REGION S OF 17N W OF 120W. THIS AMPLIFIED PATTERN IS 
EXPECTED TO REMAIN STATIONARY...WITH THE COLD FRONT CURRENTLY 
OVER NW WATERS FROM 30N136W TO 27N140W EXPECTED TO DISSIPATE 
OVERNIGHT WHILE A SECOND COLD FRONT MOVES IN THU NIGHT AND THE 
HIGH PRES RIDGE REMAINS STATIONARY. 

CLOSER TO LAND...ASCAT SHOWS WINDS IN THE 20 TO 25 KT RANGE 
CONTINUE IN THE GULF OF CALIFORNIA AT THE MOMENT. SHIP REPORTS 
SUPPORT 20 KT WINDS AS FAR SOUTH AS 18N TO THE MOUTH OF THE 
GULF. AS THE COLD FRONT OVER THE SE U.S. DIPS SOUTHWARD INTO THE 
GULF OF MEXICO...EXPECT THE PRES GRADIENT TO DECREASE ACROSS THE 
GULF OF CALIFORNIA. WINDS AT 20 KT ARE EXPECTED TO SHRINK TO N 
OF 25N WITHIN THE GULF TOMORROW.

GAP WINDS..GAP WINDS PERSIST THROUGH THE GULFS OF PAPAGAYO AND 
TEHUANTEPEC. THE COMBINATION OF STRONG TRADE WINDS IN THE 
CARIBBEAN AND LOCAL DRAINAGE EFFECTS WILL ALLOW THE FRESH WINDS 
TO PERSIST IN PAPAGAYO THROUGH WED NIGHT...DIMINISHING THROUGH 
THU. WINDS WILL INCREASE THROUGH THE GULF OF TEHUANTEPEC BY 
EARLY WED AS A COLD FRONT PUSHES INTO THE SW GULF OF MEXICO. 
WINDS WILL REACH NEAR GALE BY WED NIGHT AS THE COLD DENSE AIR 
FUNNELS THROUGH THE ISTHMUS AND INTO THE ADJACENT PACIFIC 
WATERS. 

FOR ADDITIONAL INFORMATION PLEASE VISIT 
HTTP://WWW.HURRICANES.GOV/MARINE
  
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SCHAUER