000
AXPZ20 KNHC 282137
TWDEP 

TROPICAL WEATHER DISCUSSION 
NWS TPC/NATIONAL HURRICANE CENTER MIAMI FL
2205 UTC TUE OCT 28 2008

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 
1915 UTC.

...THE ITCZ...
THE AXIS OF THE ITCZ LIES ALONG A LINE FROM 05N77W TO 08N100W TO 
10N108W TO 10N120W TO 07N140W. SCATTERED MODERATE CONVECTION CAN 
BE FOUND WITHIN 150 NM S OF AXIS FROM 110W TO 118W AND ISOLATED 
MODERATE CONVECTION LIES WITHIN 120 NM OF AXIS FROM 89W TO 100W.


...DISCUSSION...

THE MID TO UPPER LEVEL PATTERN OVER THE SUBTROPICAL PORTION OF 
THE DISCUSSION ZONE CURRENTLY SPORTS A RIDGE BOOKENDED BY 
TROUGHING MOVING INTO THE NW WATERS AND TROUGHING OVER NORTHEAST 
WATERS OFF THE BAJA PENINSULA.  ONLY A FEW PATCHES OF MID-HIGH 
LEVEL CLOUDS CAN BE FOUND ACROSS THE SUBTROPICS. THIS PATTERN IS 
PROGRESSIVE...WITH A SHARP AND ELONGATED UPPER TROUGH N AND W OF 
THE ZONE PUSHING E AND DRAGGING A COLD FRONT ACROSS NW WATERS 
WED. THIS FRONT WILL WEAKEN ON FRI AS THE MAIN SYSTEM...CUT OFF 
FROM THE NORTHERN STREAM FLOW...IS LIFTED NORTHWARD IN RESPONSE 
TO A NEW SHOT OF MID LEVEL ENERGY PASSING INTO THE SOUTHERN EDGE 
OF THE BROAD TROUGH OVER THE NORTHEASTERN PACIFIC.

IN THE TROPICS...A LOW LEVEL TROUGH EMBEDDED IN THE ITCZ ALONG 
110W IS SUPPORTING SCATTERED MODERATE CONVECTION WITHIN 180 NM 
OF TROUGH ALONG 100W FROM 10N TO 15N.  MAIN CAUSE FOR THE 
INCREASED CONVECTION IS DUE THE UPPER DIFFLUENT PATTERN E OF AN 
UPPER TROUGH. THIS FEATURE WILL BE MOVING INTO A SLIGHTLY LESS 
FAVORABLE ENVIRONMENT SO ANY DEVELOPMENT WOULD BE SLOW TO OCCUR. 

LONG PERIOD NW SWELL EMANATING FROM NW WATERS AND SE SWELL FROM 
THE SOUTHERN HEMISPHERE...WITH WAVE PERIODS IN THE 15 TO 18 
SECOND RANGE...WILL MEET OVERNIGHT TONIGHT WEST OF THE GALAPAGOS 
ISLANDS. WAVE HEIGHTS SHOULD BE ON THE RISE FROM THE 4 TO 6 FT 
RANGE TO THE 7 TO 9 FT RANGE ON THE WEST FACING SHORES OF THE 
ISLANDS THROUGH FRI. 

GAP WINDS...
THE TIGHT PRESSURE GRADIENT BETWEEN A STRONG EARLY SEASON COLD 
FRONT OVER THE SW ATLC/NW CARIBBEAN AND RIDGING EXTENDING SOUTH 
OVER MEXICO FROM A HEALTHY 1035 MB HIGH OVER THE PLAINS HAS 
PRODUCED A STRONG TEHUANTEPEC EVENT. A HI-RES QSCAT PASS FROM 
AROUND 1252 UTC REVEALED 50 KT MAX WINDS. SHIP 9HJD9 REPORTED 70 
KT WINDS AT 13Z IN THE EXIT LEFT REGION OF THE GAP WHICH 
CURRENTLY EXTENDS FROM THE GULF OF TEHUANTEPEC SOUTHWESTWARD 
TOWARD 10N99W. A QC OF THE SHIP SUGGESTED THAT IT WAS LIKELY 
BIASED 10-15 KT HIGH. THE QSCAT PASS REVEALED MAX WINDS OF 45-50 
KT JUST SW OF THE SHIP REPORT. GIVEN THIS DATA...IT IS APPARENT 
THAT STORM CONDITIONS ARE OCCURRING IN THE TEHUANTEPEC. THIS 
EARLIER PASS LIKELY CAPTURED THE PEAK OF THE EVENT AS THE HIGH 
PRES HAS WEAKENED SOMEWHAT N OF THE AREA AND THE FRONT IS 
EXPECTED TO SHIFT. HOWEVER...GALE FORCE WINDS ARE LIKELY FOR 
MUCH OF THE WEEK. 

GAP OF PAPAGAYO WINDS ARE ALSO BLOWING BUT ARE LOWER THAN 
WARNING CRITERIA. THIS EVENT...LIKE THE TEHUANTEPEC...WILL BE 
PERSISTING FOR MUCH OF THE WEEK.

$$
CANGIALOSI/SCHAUER CLARK