000
AXPZ20 KNHC 240334
TWDEP 

TROPICAL WEATHER DISCUSSION  
NWS TPC/NATIONAL HURRICANE CENTER MIAMI FL
0405 UTC SAT JAN 24 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 
0145 UTC.

...ITCZ...
THE INTERTROPICAL CONVERGENCE ZONE LIES ALONG AN AXIS FROM 
05N77W TO 01N100W TO 06N112W TO 07N119W TO 05N140W. THERE IS NO 
SIGNIFICANT CONVECTION CURRENTLY ASSOCIATED WITH THE ITCZ.

...DISCUSSION...
WHILE THERE HAS NOT BEEN A SCATTEROMETER PASS IN THE GULF OF 
TEHUANTEPEC SINCE 1154 UTC AND NO SHIP OBSERVATION IN THE AREA 
IN QUESTION...WINDS ARE BELIEVED TO BE QUICKLY DIMINISHING IN 
THE GULF OF TEHUANTEPEC AT THIS HOUR AND ARE EXPECTED TO 
TEMPORARILY DROP BELOW 20 KT THIS EVENING THROUGH SUN MORNING 
WHEN A SURGE OF NORTHERLY FLOW THROUGH THE WESTERN GULF OF 
MEXICO BEHIND A WEAKENING COLD FRONT REACHES THE PACIFIC THROUGH 
THE ISTHMUS OF TEHUANTEPEC.  IN ADDITION TO THE FRONT BEING 
RELATIVELY WEAK IN THE GULF...THE DEEP LAYER TROUGH SUPPORTING 
THIS COLD FRONT IS EXPECTED TO BE POSITIVELY TILTED...SKEWING 
THE FLOW MORE EAST OF NORTH AND PREVENTING WINDS FROM REACHING 
GALE FORCE AS THEY PUSH INTO THE GULF OF TEHUANTEPEC.  

TO THE SOUTH...THERE HAS SIMILARLY BEEN LITTLE OBSERVATIONAL 
DATA TO WORK RECENTLY WITH EXCEPT THE LAST ASCAT PASS AT 1518 
UTC.  WINDS IN THE GULFS OF FONSECA AND PAPAGAYO ARE EXPECTED TO 
LINGER IN THE 20 TO 25 KT RANGE THROUGH THE PERIOD AS THE 
PRESSURE GRADIENT REMAINS CONSISTENTLY STRONGER OVER THIS 
REGION....WEDGED BETWEEN MEAN HIGH PRESSURE OVER THE NORTHERN 
GULF OF MEXICO AND NE MEXICO AND LOW PRESSURE OVER NORTHERN 
COLOMBIA.  EVEN FURTHER SOUTH...WINDS HAVE BEGUN TO DIMINISH IN 
THE GULF OF PANAMA ACCORDING TO THE 1518 UTC ASCAT PASS WHICH NO 
LONGER SHOWED WINDS IN THE 20 TO 25 KT RANGE.  WITH WINDS IN THE 
SW CARIBBEAN TURNING MORE EAST OF NORTH...EXPECT THE WINDS 
BLEEDING THROUGH PANAMA INTO THE PACIFIC TO SOON DROP BELOW 20 
KT...IF THEY HAVE NOT ALREADY DONE SO.

ELSEWHERE...THE DEEP LAYERED LOW CENTERED NEAR 32N130W IS 
EXPECTED TO ACQUIRE MORE NORTHERN STREAM ENERGY OVER THE NEXT 
FEW DAYS...CAUSING THE SUPPORTING TROUGH TO AMPLIFY AND SLOWLY 
DRIFT SOUTHEASTWARD BEFORE CLOSING OFF A MID TO UPPER LEVEL LOW 
OVER NW WATERS SUN/MON. THE SURFACE PRESSURE GRADIENT OVER NW 
WATERS IS EXPECTED TO TIGHTEN AS HIGH PRESSURE TO ITS NW 
ADVANCES EASTWARD AND THIS LOW IS REINVIGORATED...ALLOWING FOR 
WINDS TO BUILD TO THE 20 TO 30 KT RANGE HERE SUN. MEANWHILE... 
THE HIGH PRESSURE TO THE EAST OF THE LOW IS EXPECTED TO BE 
SQUEEZED BETWEEN THIS LOW AND LOW PRESSURE OVER NW MEXICO AND 
THE SW U.S...INCREASING WINDS TO 20 KT OVER THE MOUTH OF THE 
GULF OF CALIFORNIA OVER THE WEEKEND AND TO 20 KT OFF THE N 
CENTRAL BAJA CALIFORNIA COAST SUN EVENING.

FINALLY...THE CONVECTION ASSOCIATED WITH THE AREA OF BROAD UPPER 
LEVEL DIFFLUENCE ON THE SE EDGE OF THE WEAK UPPER TROUGH FROM 
21N107W TO 10N116W HAS WEAKENED...WITH ONLY ISOLATED MODERATE 
CONVECTION SEEN WITHIN 75 NM OF LINE FROM 14N113W TO 18N105W.  
WITH THE UPPER LEVEL SOUTHERLY FLOW EXPECTED TO INCREASE TO THE 
40 TO 50 KT RANGE ACROSS THIS REGION OVER THE NEXT FEW 
DAYS...CONVECTION HERE IS EXPECTED TO WANE AND WILL MOST LIKELY 
SHIFT WESTWARD TOWARD THE DIFFLUENT REGION AHEAD OF THE DEEP 
LAYER LOW OVER NW WATERS...PRIMARILY S OF 20N W BETWEEN 110W AND 
130W.

$$
SCHAUER CLARK