000
AXPZ20 KNHC 270329
TWDEP 

TROPICAL WEATHER DISCUSSION  
NWS TPC/NATIONAL HURRICANE CENTER MIAMI FL
0405 UTC TUE JAN 27 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 
0130 UTC.

...ITCZ...
INTERTROPICAL CONVERGENCE ZONE CAN BE FOUND ALONG THE AXIS FROM 
04N77W TO 01N100W TO 02N110W TO 08N127W TO 06N140W. SCATTERED 
MODERATE CONVECTION CAN BE FOUND WITHIN 90 NM OF THE ITCZ AXIS 
FROM 124W TO 127W.

...DISCUSSION...
THE MID LEVEL CUT OFF LOW OVER NW WATERS IS CURRENTLY WELL 
DEFINED ON VISIBLE SATELLITE IMAGERY AND HAS NOW INDUCED A 
SURFACE LOW NEAR 22N133W.  STRONG UPPER LEVEL DIFFLUENCE BETWEEN 
THE REAR RIGHT QUADRANT OF THE SOUTHWESTERLY JET ON THE NE SIDE 
OF THE LOW AND LEFT FRONT QUADRANT OF THE APPROACHING 
WEST-NORTHWESTERLY JET ON THE SOUTH SIDE OF THE LOW HAS BECOME A 
SIGNIFICANT FOCUS FOR CONVECTION WITH NUMEROUS MODERATE AND 
ISOLATED STRONG CONVECTION FOUND FROM 09N TO 29N BETWEEN 117W 
AND 130W.  NUMEROUS MODERATE CONVECTION CAN ALSO BE FOUND WITHIN 
210 NM N QUADRANT OF THE SURFACE LOW CENTER. THIS SURFACE LOW IS 
EXPECTED TO DISSIPATE BY TUE EVENING AND THE REMAINING AREA OF 
LOW PRESSURE IS EXPECTED TO GRADUALLY WEAKEN THROUGH WED AS THE 
UPPER TO MID LEVEL LOW WEAKENS AND IS FORCED NORTHWARD ON THE 
LEADING EDGE OF THE DEEP LAYERED LOW N OF HAWAII. HIGH PRESSURE 
HAS BUILT TO THE N OF THE SURFACE LOW AND THE PRESSURE GRADIENT 
BETWEEN THESE TWO SURFACE FEATURES WILL KEEP WINDS OVER NW 
WATERS AT GALE FORCE THROUGH WED MORNING.  THE ASCAT PASS AT 
1914 UTC CONFIRMED AN AREA OF GALE FORCE WINDS AND GREATER IN 
THE N QUADRANT OF THE LOW TO 480 NM AND SHIP OBSERVATION WCHF 
NEAR 29.5N136.5W AT 0000 UTC REPORTED 34 KT WINDS.

THE PRESSURE GRADIENT BETWEEN LOW PRESSURE OVER NORTHERN MEXICO 
AND HIGH PRESSURE OFF THE W COAST OF BAJA CALIFORNIA HAS 
INCREASED THE WINDS ABOVE 20 KT WITHIN 180 NM OF THE W COAST OF 
THE BAJA N OF 25N.  THE 1400 UTC QUIKSCAT PASS CONFIRMED THE 
INCREASE IN WINDS HERE WHICH IS EXPECTED TO EXPAND SOUTHWARD 
ALONG THE ENTIRE BAJA WEST COAST OVER THE NEXT 24 HOURS AS LOW 
PRESSURE OVER THE U.S. PLAINS DROPS SOUTH OF THE RIO GRANDE.  
HOWEVER...THE 1732 UTC ASCAT PASS AND THE SHIP OBSERVATION PHHD 
NEAR 25N113W 16 KT AT 0000 UTC SHOWED THAT WINDS OVER 20 KT HAVE 
YET TO PUSH AS FAR S AS 25N ALONG THE W COAST OF THE BAJA. THIS 
LOW PRESSURE SYSTEM WILL ALSO BRING A COLD FRONT AND 20 TO 25 KT 
NORTHERLY FLOW SOUTHWARD THROUGH THE GULF OF CALIFORNIA 
BEGINNING TOMORROW AFTERNOON.

GAP WINDS...THE LAST REPORT AT 2200 UTC FROM SHIP ZCDM7 NEAR 
15N95.6W NEAR THE GULF OF TEHUANTEPEC HAD NE WINDS AT 18 KT.  
LOW RESOLUTION QUIKSCAT AT 0046 UTC SHOWS WINDS ARE STILL 20 TO 
25 KT N OF 15N.  WINDS WILL CONTINUE DIMINISHING HERE OVERNIGHT 
WITH WINDS BELOW 20 KT BY TUE AFTERNOON AS THE PRESSURE GRADIENT 
TO THE N ACROSS THE SOUTHERN GULF OF MEXICO SLACKENS AHEAD OF 
THE APPROACHING COLD FRONT.

IN THE GULF OF PAPAGAYO...NE WINDS IN THE 20 TO 25 KT RANGE ARE 
REPORTED BY THE 1556 UTC ASCAT PASS TO REACH AS FAR AS 300 NM 
DOWNWIND.  THIS PASS ALSO SHOWED AN INCREASE IN WINDS TO 20 KT 
DOWNWIND OF THE GULF OF FONSECA.  WITH STRONG TRADES EXPECTED TO 
CONTINUE IN THE WESTERN CARIBBEAN...LITTLE CHANGE IS EXPECTED IN 
CONDITIONS HERE OVER THE NEXT FEW DAYS.

IN THE GULF OF PANAMA...THE QUIKSCAT PASS AT 2306 UTC CONFIRMED 
THAT WINDS ARE BELOW 20 KT AT THE MOMENT.  FORECAST GUIDANCE 
DOES NOT INCREASE THE WINDS HERE OVER THE NEXT FEW DAYS.

$$
SCHAUER CLARK