000
AXPZ20 KNHC 260325
TWDEP 

TROPICAL WEATHER DISCUSSION
NWS NATIONAL HURRICANE CENTER MIAMI FL
0405 UTC WED JAN 26 2011

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 
0315 UTC.

...ITCZ...

THE ITCZ AXIS FLUCTUATES BETWEEN 04N AND 05N FROM THE COAST OF 
COLOMBIA TO BEYOND 140W. SCATTERED MODERATE ISOLATED STRONG 
CONVECTION IS NOW ONLY NOTED WITHIN 60 NM OF 05.5N93.5W. 
SCATTERED MODERATE CONVECTION IS NOTED WITHIN 90 NM OF 05N129W 
AND 08N130W.

...DISCUSSION...

AN UPPER TROUGH EXTENDS ACROSS THE NORTHERN PORTION OF THE 
DISCUSSION AREA FROM 32N94W TO 24N106W. AN UPPER CYCLONE HAS CUT 
OFF FROM THE TROUGH AT 22N126W WITH THE TROUGH EXTENDING W 
BEYOND 21N140W. DRY UPPER AIR IS INDICATED WITHIN 120 NM OF THE 
UPPER TROUGH AXIS AND ALSO AROUND THE UPPER CYCLONE. A BAND OF 
UPPER MOISTURE IS SPREADING SE OVER THE DISCUSSION AREA N OF 29N 
E OF 120W AND AS FAR E AS W TEXAS...BUT A SHORT WAVE TROUGH NOW 
SWEEPING SE ACROSS SOUTHERN FLORIDA IS ACCOMPANIED BY DRIER AIR
THAT WILL QUICKLY REPLACE THIS MOIST AIR. THE UPPER CYCLONE IS 
EXPECTED TO WEAKEN AND ACCELERATE NE CROSSING THE NORTHERN BAJA 
PENINSULA ON FRI.

FURTHER S...A BROAD UPPER RIDGE DOMINATES THE TROPICS BETWEEN 
140W AND 110W. A MOISTURE PLUME EXTENDS NE ACROSS THE EQUATOR 
BETWEEN 130W AND 150W AND MERGES WITH DEBRIS MOISTURE FROM THE 
SCATTERED MODERATE ITCZ CONVECTION NEAR 129W...RESULTING IN A 
MOIST UPPER LEVEL UNDER THE RIDGE. A BROAD UPPER TROUGH IS NOTED 
OVER THE SUBTROPICS BETWEEN 110W AND 95W WITH THE WESTERN 
EXTENSION OF AN UPPER RIDGE EXTENDING OVER THE DEEP TROPICS E OF 
92W. UPPER DIFFLUENCE IS STILL ENHANCING THE CONVECTION 
PREVIOUSLY DESCRIBED NEAR 06N93W...BUT THE DEBRIS MOISTURE 
QUICKLY EVAPORATES JUST TO THE NE BEFORE REACHING CENTRAL 
AMERICA.    

AT THE LOW LEVELS A RIDGE EXTENDS ALONG 32N132W TO 12N94W. A 
SMALL AREA OF 15-20 KT NE TRADES IS OBSERVED FROM 09N TO 13N W 
OF 130W WHILE THE ENTIRE PACIFIC WATERS FROM 32N TO THE EQUATOR 
BETWEEN 92W AND 140W IS EXPERIENCING 8-10 FT SEAS IN NW SWELL 
MIXING WITH NE WIND WAVES IN THE LOW LEVEL FLOW AROUND THE 
RIDGE. THE PARENT SURFACE HIGH PRESSURE WILL SHIFT SE INTO THE 
AREA NEAR 28N135W EARLY THU. THE HIGH WILL THEN WEAKEN AS 
SOUTHERLY SURFACE WINDS INCREASE IN ADVANCE OF A COLD FRONT 
MOVING TO A POSITION FROM 32N136W TO 28N142W BEFORE STALLING.   

THE SURFACE PRESSURE GRADIENT IS FORECAST TO TIGHTEN OVER THE 
GULF OF CALIFORNIA TONIGHT SUPPORTING AN INCREASE IN NW WINDS 
TO 20-25 KT THU OVER THE NORTHERN GULF WATERS...PERSISTING 
THROUGH EARLY FRI.

GAP WINDS...THE PASSAGE OF A COLD FRONT IN THE BAY OF CAMPECHE 
WILL RESULT IN NORTHERLY WINDS FUNNELING THROUGH THE CHIVELA 
PASS INTO THE GULF OF TEHUANTEPEC INCREASING TO 20-30 KT BY 
SUNRISE WED. THESE NORTHERLY WINDS WILL CONTINUE TO PULSE INTO 
THE WEEKEND ESPECIALLY AROUND SUNRISE. 

$$
NELSON