000
AXPZ20 KNHC 021536
TWDEP 

TROPICAL WEATHER DISCUSSION
NWS TPC/NATIONAL HURRICANE CENTER MIAMI FL
1605 UTC FRI APR 02 2010

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 
1400 UTC.

...ITCZ...

THE INTERTROPICAL CONVERGENCE ZONE WAS ANALYZED ALONG 06N77W TO 
04N106W TO 05N115W TO 03N125W TO 04N140W. SCATTERED MODERATE 
WITH ISOLATED STRONG CONVECTION WAS WITHIN 120 NM EITHER SIDE OF 
THE ITCZ AXIS BETWEEN 82W AND 96W. SCATTERED MODERATE CONVECTION 
WAS WITHIN 180 NM N AND 90 NM S OF THE ITCZ AXIS W OF 109W.

...DISCUSSION...

SUBTROPICS...
THE LONG-WAVE TROUGH OVER THE SW U.S. AND NW MEXICO WILL MOVE E 
INTO THE PLAINS TODAY AND TURN NEGATIVE TILT OVER THE CENTRAL 
U.S. SAT. THE TROUGH AXIS CURRENTLY LIES FROM 30N109W TO 
14N140W...WITH SHORTWAVE ENERGY SW OF THIS MAIN TROUGH EXTENDING 
THE TROUGH AXIS THROUGH FORECAST WATERS. THIS ENERGY WILL 
DECOUPLE FROM THE PROGRESSIVE MAIN UPPER TROUGH OVER THE 
WEEKEND. THE PRES GRADIENT BETWEEN THE TROUGHING AT THE SURFACE 
OVER THE U.S. AND MEXICO AND THE RIDGE AXIS OVER N WATERS FROM 
28N140W TO 20N108W IS SPURRING NW TO N WINDS IN THE 20 TO 25 KT 
RANGE WITHIN 270 NM OF THE W COAST OF BAJA CALIFORNIA AS 
CONFIRMED BY THE 0448 UTC ASCAT PASS AND NUMEROUS SHIP 
OBSERVATIONS AT 1200 UTC. THE SHIPS ALSO CONFIRM THE WW3 MODEL 
MAX SIGNIFICANT WAVE HEIGHTS AT 16 FT OVER NE WATERS. NW TO N 
WINDS INDUCED BY THIS PRES GRADIENT ARE ALSO FOUND IN THE 
SOUTHERN GULF OF CALIFORNIA...WITH SHIP C6FV9 REPORTING SEAS TO 
10 FT IN N SWELL IN THE MOUTH OF THE GULF NEAR 22N108W AT 1200 
UTC. THESE WINDS WILL DIMINISH IN THE GULF OF CALIFORNIA OVER 
NIGHT AND WILL SHRINK NORTHWARD AND TO THE REGION CLOSER TO THE 
W COAST OF BAJA CALIFORNIA OVER THE WEEKEND. THE DEEP LAYER 
RIDGE JUST NW OF THE AREA IS BEING FORCED W AS ENERGY FROM THE N 
PACIFIC ENCROACHES ON ITS N EDGE AND THE LINGERING SHORTWAVE 
ENERGY OVER W WATERS WEAKENS THE RIDGING ON ITS SE SIDE. AT THE 
SURFACE...THE RIDGE AXIS WILL WEAKEN AND BE FORCED SOUTHWARD BY 
A COLD FRONT ASSOCIATED WITH THE ENERGY MOVING IN FROM THE N. 
THIS WILL SHIFT THE BAND OF TRADE WINDS CURRENTLY OVER W WATERS 
FROM 07N TO 25N SOUTHWARD TO 08N TO 15N BY SUN MORNING.

TROPICS...
THERE IS A TROUGH EMBEDDED IN THE ITCZ FROM 08N128W TO 02N130W. 
THIS TROUGH WAS EASILY IDENTIFIED USING THE 0624 UTC ASCAT PASS 
WHICH SHOWED N TO NE WINDS TO 25 KT W OF THE TROUGH AND E WINDS 
AT 10 TO 15 KT E OF THE TROUGH. THE WESTERN HALF OF THE ITCZ 
WHERE THIS TROUGH RESIDES IS THE MOST CONVECTIVELY ACTIVE 
PORTION. THIS PORTION OF THE ITCZ LIES UNDER BROADLY DIFFLUENT 
FLOW ALOFT BETWEEN THE 60-70 KT SOUTHWESTERLY UPPER JET ON THE 
SE SIDE OF THE AFOREMENTIONED UPPER TROUGH AXIS AND ANTICYCLONIC 
FLOW ON THE NORTHERN EDGE OF A RIDGE AXIS FOUND ALONG 125W S OF 
08N. THERE IS SOME DEEP CONVECTION NOTED ALONG THE ITCZ AXIS 
PRIMARILY E OF 90W AND NEAR THE COAST OF COLOMBIA AND NORTHERN 
ECUADOR. THIS AREA LIES IN A DIFFLUENT REGION ALOFT BETWEEN THE 
WEST EDGE OF A RIDGE AXIS THAT EXTENDS E INTO NORTHERN COLOMBIA 
AND AN ANTICYCLONE CENTERED NEAR 08N93W. 

GAP WINDS...
THE 0302 UTC ASCAT PASS CAPTURED THE AREA DOWNWIND OF THE GULF 
OF PAPAGAYO W OF 87W AND SHOWED LIGHT WINDS. THE EVENING TIME 
PERIOD WHEN THIS PASS OCCURRED WAS DURING THE DIURNAL MINIMUM 
FOR DRAINAGE FLOW FROM PAPAGAYO. WHILE THERE HAVE NOT BEEN NEW 
OBSERVATIONS SINCE THE ASCAT PASS...THE MODELS SHOW WINDS TO 25 
KT IN THE GULF OF PAPAGAYO AT THE PRESENT TIME GENERATED BY THE 
PRES GRADIENT BETWEEN THE RIDGE AXIS OVER THE GULF OF MEXICO AND 
LOW PRES OVER COLOMBIA. LOOK FOR WINDS TO DIMINISH TO 20 KT BY 
SAT MORNING AS THE DEEP LAYERED TROUGH CURRENTLY OVER CENTRAL TO 
EASTERN MEXICO PUSHES INTO THE WESTERN GULF OF MEXICO AND SHOVES 
THE RIDGE AXIS EASTWARD...DECREASING THE PRES GRADIENT.

FOR ADDITIONAL INFORMATION PLEASE VISIT 
HTTP://WWW.HURRICANES.GOV/MARINE

$$
SCHAUER