000
AXPZ20 KNHC 121530
TWDEP 

TROPICAL WEATHER DISCUSSION
NWS TPC/NATIONAL HURRICANE CENTER MIAMI FL
1605 UTC FRI MAR 12 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 
1500 UTC.

...ITCZ...

THE ITCZ AXIS IS CENTERED ALONG 06N77W TO 04N95W TO 05N110W TO 
04N125W TO 04N140W. SCATTERED MODERATE TO ISOLATED STRONG 
CONVECTION IS WITHIN 130-150 NM S OF AXIS BETWEEN 88W AND 98W. 
SCATTERED MODERATE CONVECTION WITHIN 135 NM N OF AXIS W OF 135W. 

...DISCUSSION...

A DEEP LAYER TROUGH IS QUICKLY MOVING E ACROSS THE NW PORTION OF 
THE AREA WHILE AMPLIFYING. THE ASSOCIATED COLD FRONT HAS ENTERED 
THE NW CORNER OF THE FORECAST REGION AND STRETCHES FROM 30N138W 
TO 29N140W. TO THE E OF THE TROUGH...A LARGE MID/UPPER RIDGE IS 
AMPLIFYING N OF 25N AND E OF 125W WITH MEAN N TO S RIDGE AXIS 
ACROSS THE WRN U.S. A JET STREAM BRANCH WITH JET CORE WINDS IN 
THE RANGE OF 90-110 KT ROUNDS THE BASE OF THE TROUGH ENTERING 
THE DISCUSSION AREA AT 21N140W THEN CONTINUES E-NE CROSSING 
SOUTHERN BAJA CALIFORNIA AND NORTHERN MEXICO INTO THE NW GULF OF 
MEXICO WHERE WINDS INCREASE TO 150 KT. A 250-300 NM WIDE SWATH 
OF MODERATE SUBSIDENCE INDICATIVE OF DRY...STABLE AIR IS TO THE 
SE OF THE TROUGH TO NEAR 125W...AND INCREASES TO AROUND 450 NM N 
OF JET E OF 125W INCLUDING MOST OF THE BAJA PENINSULA AND 
NORTHERN MEXICO N OF 24N. THE TROUGH IS FORECAST TO MOVE EWD 
INLAND THE WESTERN U.S. IN ABOUT 24HOURS WHILE THE COLD FRONT 
WEAKENS. THE MAIN IMPACT FROM THIS COLD FRONT WILL BE A NEW 
SURGE OF NW SWELL SPREADING ACROSS THE AREA WITH SIGNIFICANT 
WAVE HEIGHTS INCREASING TO 14 FT WITHIN 24 HOURS. 

TO THE S OF THE JET STREAM...BROAD UPPER LEVEL ANTICYCLONIC 
CIRCULATION CENTERED NEAR 7N104W EXTENDS A RIDGE E-NE TO OVER 
CENTRAL AMERICA INTO THE CARIBBEAN SEA. UPPER DIFFLUENT FLOW 
PATTERN TO THE SW OF THE ANTICYCLONE IS HELPING TO SUSTAIN ITCZ 
CONVECTION E OF 98W. A SECOND RIDGE AXIS EXTENDS SW OF THE 
ANTICYCLONE TO NEAR 3N128W. THE ANTICYCLONE IS EXPECTED TO 
CHANGE LITTLE OVER THE NEXT 24 HRS...THEN BEGIN TO SHIFT E IN 
36-48 HRS.

AT THE SURFACE...A 1024 MB HIGH IS ANALYZED NEAR 27N133W WITH A 
RIDGE SE TO NEAR 20N110W COVERING THE AREA N OF 14N AND W OF 
110W. THIS HIGH CENTER IS FORECAST TO DISSIPATE WITHIN THE NEXT 
24 HRS AS ANOTHER HIGH PRES N OF THE AREA MOVES ESE. UNDER THIS 
WEATHER PATTERN...EXPECT AN INCREASE IN THE AREA OF THE TRADE 
WINDS AS WELL AS AN INCREASE IN WINDS AND SEAS THROUGH THE GULF 
OF CALIFORNIA AND NEAR THE WEST COAST OF MEXICO PARTICULARLY 
FROM 14N TO 20N E OF 107W. CURRENTLY...A BROAD AREA OF STRONG NE 
TRADE WINDS FROM 06N TO 21N W OF 120W IS NOTED PER A PAIR OF 
ASCAT PASSES AT 0520 UTC AND 0700 UTC AND SOME SHIP REPORTS.  

GAP WINDS...
THE NEXT TEHUANTEPEC GAP WIND EVENT IS FORECAST TO BEGIN EARLY 
THIS EVENING WITH N-NE WINDS OF 20 TO 25 KT...THEN INCREASE TO 
POSSIBLY 30 KT IN ABOUT 24 HRS. WINDS WILL DROP TO BELOW 20 KT 
IN ABOUT 36 HRS.

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

$$
GR/JAH