000
AXPZ20 KNHC 080329
TWDEP 

TROPICAL WEATHER DISCUSSION
NWS NATIONAL HURRICANE CENTER MIAMI FL
0405 UTC TUE NOV 08 2011

TROPICAL WEATHER DISCUSSION FOR THE EASTERN PACIFIC OCEAN FROM 
THE EQUATOR TO 32N...EAST OF 140W. THE FOLLOWING INFORMATION IS 
BASED ON SATELLITE IMAGERY...WEATHER OBSERVATIONS...RADAR...AND 
METEOROLOGICAL ANALYSIS.

BASED ON 0000 UTC SURFACE ANALYSIS AND SATELLITE IMAGERY THROUGH 
0230 UTC.

...INTERTROPICAL CONVERGENCE ZONE/MONSOON TROUGH...MONSOON 
TROUGH EXTENDS FROM 08N84W TO 11N115W TO 10N120W...THEN 
TRANSITIONS TO ITCZ AXIS FROM 10N120W TO 09N130W TO 08N140W. 
SCATTERED MODERATE ISOLATED STRONG CONVECTION WITHIN 60 NM OF 
AXIS W OF 110W.

...DISCUSSION...
UPPER FLOW N OF 20N IS BECOMING MORE ZONAL AS AN EXITING DEEP 
LAYER TROUGH ALONG 115W CONTINUES TO PUSH E THROUGH THE ROCKIES 
AND BAJA CALIFORNIA. THE PRES GRADIENT HAS BECOME TIGHTER IN THE 
PACIFIC WATERS OFF THE BAJA COAST...AS HIGH PRES BUILDS FROM THE 
WEST. RECENT SHIP OBSERVATIONS SHOW 20 TO 25 KT NW WINDS ALONG 
THE NORTHERN COAST OF BAJA CALIFORNIA. A REINFORCING SHORT WAVE 
TROUGH WITHIN THE NW FLOW ALOFT IS BARELY DISCERNIBLE ON WATER 
VAPOR IMAGERY N OF THE AREA ALONG 133W. THIS WILL AMPLIFY 
SLIGHTLY AND SHIFT INTO THE AREA OFF THE N BAJA COAST THROUGH 
EARLY TUE. THE SHORT WAVE RIDGING THAT FOLLOWS THIS TROUGH WILL 
REINFORCE THE SURFACE HIGH PRES THAT WILL BE CENTERED NEAR 
30N130W BY LATE TUE. THIS IN TURN WILL MAINTAIN A BROAD AREA OF 
20 KT TRADE WINDS THAT GENERALLY COVER THE AREA N BETWEEN THE 
ITCZ AND 25N W OF 115W AS NOTED IN ASCAT SCATTEROMETER DATA FROM 
THE PAST 8 HOURS. 

BY 48 HOURS...A LONG WAVE TROUGH MIGRATES THROUGH THE CENTRAL 
PACIFIC N OF HAWAII TO 140W N OF 30N. AN ASSOCIATED STRONG COLD 
FRONT MOVES SE INTO THE EASTERN PACIFIC...REACHING FROM 30N135W 
TO 27N140W.

ASCAT SCATTEROMETER DATA AND TOGA BUOY OBSERVATIONS INDICATED AN 
AREA OF SE 20 KT WINDS S OF THE ITCZ W OF 120W. FAIRLY WARM SEA 
SURFACE TEMPERATURES IN THIS AREA ARE ALLOWING ENHANCED SE 
GRADIENT FLOW BETWEEN THE EQUATOR AND THE ITCZ TO MIX TO THE 
SURFACE. CONVERGENCE OF THESE WINDS WITH THE FRESH NE TRADES IS 
RESULTING IN NEAR CONTINUOUS MODERATE TO STRONG CONVECTION ALONG 
THE ITCZ W OF 125W. FURTHER E ALONG THE ITCZ...A SURFACE TROUGH 
PERSISTS NEAR 115W. THIS QUASI-STATIONARY SURFACE FEATURE IS AN 
ARTIFACT OF UPPER LEVEL DIVERGENCE ON THE N SIDE OF AN UPPER 
CYCLONE CENTERED NEAR 05N105W...S OF THE DEEP LAYER TROUGH N OF 
THE AREA ALONG 115W. 

ALTHOUGH THERE ARE SCANT DATA TO VERIFY IT...GLOBAL MODELS 
SUGGEST SW WINDS ARE INCREASING TO 20 KT S OF PANAMA OVERNIGHT. 
A SHIP OFF WESTERN PANAMA DID REGISTER 20 KT EARLIER TODAY. A 
MID LEVEL ROTATION IS EVIDENT ON SATELLITE IMAGERY S OF 
PANAMA...ALONG WITH SCATTERED SHOWERS AND TSTMS. WEAK LOW PRES 
MAY FORM IN THIS AREA OR JUST TO NORTH OVER THE NEXT 24 
HOURS...MAINTAINING 20 KT WINDS. 
 
FOR THE GULF OF CALIFORNIA...LAND BASED OBSERVATIONS FROM SAN 
FELIPE IN THE FAR NW COAST OF THE GULF OF CALIFORNIA ALSO SHOWED 
WINDS NW WINDS TO 20 KT...A GOOD INDICATION THAT FRESH NW FLOW 
PERSISTS OVER GULF OF CALIFORNIA WATERS. WINDS DIMINISH OVER THE 
NORTHERN GULF OVERNIGHT AS THE HIGH PRES BUILDS INTO THE AREA 
FROM THE WEST. THIS WILL ALSO PRESENT A TIGHTER GRADIENT FURTHER 
S DOWN THE GULF THROUGH TUE. WINDS WILL INCREASE AGAIN OVER THE 
NORTHERN GULF STARTING TUE NIGHT AS THE HIGH PRES OVER THE NE 
PACIFIC BUILDS EASTWARD TO THE NORTH OF THE GULF OVER THE GREAT 
BASIN. GLOBAL MODELS ARE NOT SHOWING GALE FORCE WINDS AT THIS 
TIME...MOST LIKELY DUE TO THE PRESENCE OF THE RESIDUAL SURFACE 
HIGH PRES OFF THE N BAJA COAST. 

GULF OF TEHUANTEPEC...STATION SALINA CRUZ ON THE SOUTH COAST OF 
THE ISTHMUS OF TEHUANTEPEC INDICATED 20 KT N WIND EARLIER THIS 
EVENING. THIS IS LIKELY DUE TO A TIGHTER PRES GRADIENT OVER THE 
WESTERN GULF OF MEXICO BETWEEN HIGH PRES OVER THE SE UNITED 
STATES AND A TROUGH OVER CENTRAL MEXICO. WINDS OVER THE WESTERN 
GULF ASSOCIATED WITH THE TIGHTER GRADIENT ARE FUNNELING S 
THROUGH THE GAP AND INTO THE GULF OF TEHUANTEPEC...BUT SHOULD BE 
LIMITED TO 20 KT CLOSE TO SHORE...AND DIMINISH TOMORROW MORNING. 
LOOKING AHEAD...A STRONG COLD FRONT WILL MOVE THROUGH THE 
WESTERN GULF OF MEXICO WED. NORTHERLY WINDS AT 15 TO 20 KT WILL 
SURGE INTO THE GULF OF TEHUANTEPEC AS EARLY AS LATE WED POSSIBLY 
INCREASING TO GALE FORCE EARLY THU.

$$
CHRISTENSEN