000
AXPZ20 KNHC 271606
TWDEP 

TROPICAL WEATHER DISCUSSION
NWS TPC/NATIONAL HURRICANE CENTER MIAMI FL
1605 UTC FRI NOV 27 2009

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

BASED ON 1200 UTC SURFACE ANALYSIS AND SATELLITE IMAGERY THROUGH 
1500 UTC.

...ITCZ...
AXIS ANALYZED ALONG 07N77W TO 08N89W TO 06N94W TO 05N102W TO 
08N120W TO 08N140W.  SCATTERED MODERATE CONVECTION WAS WITHIN 
150 NM OF AXIS FROM 85W TO 97W. SCATTERED TO NUMEROUS MODERATE 
TO STRONG CONVECTION WAS WITHIN 210 NM S OF AXIS BETWEEN 114W TO 
121W. SCATTERED MODERATE TO STRONG CONVECTION WAS WITHIN 150 NM 
OF AXIS W OF 121W.  

...DISCUSSION...
SRN STREAM MID-UPPER LEVEL LONGWAVE TROUGH HAS MOVED UNDERNEATH 
NRN STREAM UPPER RIDGE...AND EXTENDED FROM NW NEW MEXICO TO 
24N108W TO LINGERING MID LEVEL TROUGHING ALONG 16N121W. MODERATE 
TO STRONG SUBSIDING AIR PREVAILED NW OF AXIS.  A SHARP UPPER 
RIDGE ALONG 134W N OF 08N CONTINUES TO PROVIDE AMPLE VENTILATION 
AND DIFFLUENCE ALOFT FOR SCATTERED MODERATE TO STRONG CONVECTION 
ALONG THE ITCZ W OF 114W. A WEAK LOW LEVEL TROUGH-CONVERGENCE 
LINE IS REFLECTED BELOW THE SW END OF THE ABOVE LONGWAVE 
TROUGH...WITH 20 KT NELY TRADES DAMMED UP AGAINST IT TO THE 
NW...WHILE AN ELY PERTURBATION IN THE ITCZ WAS ALONG 120W.   A 
SECOND LONG WAVE AND DEEP LAYER TROUGH WAS APPROACHING THE NW 
CORNER OF THE BASIN BUT WAS EXPECTED TO SHIFT NE AND SHEAR OUT 
OVER THE RIDGE AS IT WILL LIKELY BLOCK MUCH FURTHER SE 
INTRUSION.  A CARIBBEAN UPPER RIDGE EXTENDED INTO E PAC E OF 
92W. 

ELSEWHERE AT THE SURFACE...
A COLD FRONT CURRENTLY FROM 30N130W TO 28N140W WILL CONTINUE TO 
WEAKEN TO A SHEAR AXIS AND BECOMES DIFFUSE NEXT 24 HOURS AS THE  
SUPPORTING UPPER LEVEL TROUGH SHIFT NE. A 1036 MB SURFACE HIGH 
NW OF THE BASIN WILL MOVE SE AND SQUEEZE THE PRES GRADIENT 
AGAINST THE CALIFORNIA COAST...AND INTENSIFY THE NE TRADES TO 
20-30 KT...AS THE LOW LEVEL CONVERGENCE LINE JUST W OF 120W
REMAINS NEARLY STATIONARY. LARGE LONG PERIOD NWLY SWELLS WILL 
CONTINUE TO PROPAGATE SE ACROSS THE E PAC W OF 
110W....MAINTAINING SEAS 8-15 FT...HIGHEST NW. 

...GAP WINDS...
A HEALTHY HIGH PRES 1026 MB BEHIND A GULF OF MEXICO COLD FRONT 
CONTINUES TO FUNNEL COLD AIR ACROSS MEXICO AND THROUGH THE GULF 
OF TEHUANTEPEC WITH STORM FORCE WINDS EXPECTED TO CONTINUE 
THROUGH 21Z-00Z THIS EVENING...THEN DIMINISH TO GALE FORCE 
THROUGH SAT EVENING BEFORE DROPPING 20-25 KT OVERNIGHT SAT. 
THE CRUISE SHIP STAR PRINCESS WAS PASSING S OF THIS STORM FORCE 
GAP WIND FLOW THIS MORNING...WITH ITS ELEVATED INSTRUMENTATION 
REPORTING 66-80 KT WINDS...LIKELY UNREPRESENTATIVE OF SURFACE 
CONDITIONS...NOT TO MENTION UNCOMFORTABLE FOR PASSENGERS.

EASTERLY TRADES IN W CARIBBEAN WILL CONTINUE TO CHANNEL WINDS 
THROUGH GULF OF PAPAGAYO AND DOWNSTREAM WATERS TO NEAR 90W 
THROUGH SUN TO MAINTAIN A FRESH TO STRONG BREEZE. 

$$
STRIPLING