000
AXPZ20 KNHC 131006
TWDEP 

TROPICAL WEATHER DISCUSSION 
NWS NATIONAL HURRICANE CENTER MIAMI FL
1005 UTC MON FEB 13 2012

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 0600 UTC SURFACE ANALYSIS AND SATELLITE IMAGERY THROUGH 
0830 UTC.

...INTERTROPICAL CONVERGENCE ZONE/MONSOON TROUGH...

THE MONSOON TROUGH EXTENDS FROM 09N75W TO 0.5N84W TO 03N91W TO 
02N100W TO 07N111W TO 01N134W. ISOLATED TO SCATTERED MODERATE 
CONVECTION NOTED WITHIN 150 NM EITHER SIDE OF TROUGH BETWEEN 80W 
AND 132W. THE MONSOON TROUGH REMAINS UNUSUALLY WELL DEFINED FOR 
THIS TIME OF YEAR...AND IS PRODUCING MODEST CONVECTION 
THROUGHOUT ITS ENTIRE LENGTH. GLOBAL MODELS SHOW THE TROUGH 
CONTINUING ACROSS THE REGION FOR THE NEXT FEW DAYS BEFORE 
BEGINNING TO BREAK DOWN W OF 12OW BY MID WEEK.

...DISCUSSION...

A BROAD MIDDLE TO UPPER LEVEL TROUGH COVERS THE AREA N OF 12N 
AND 110W. AN UPPER LEVEL SHORTWAVE TROUGH IS SWINGING E THROUGH 
THIS BROAD TROUGH ACROSS THE N HALF OF BAJA CALIFORNIA AND INTO 
FAR NW MEXICO. A SECOND LONGER WAVE TROUGH MOVING SE HAS BEGUN 
TO ENTER NW PORTIONS OF THE AREA. UPPER LEVEL WESTERLIES 
GENERALLY PREVAIL ACROSS THE AREA S OF THESE FEATURES AND W OF 
120W.

A STRONG AND PERSISTENT UPPER LEVEL RIDGE IS ANCHORED OVER 
NORTHERN S AMERICA NEAR 05N69W AND EXTENDS NW ACROSS CENTRAL 
AMERICA TO GUATEMALA THEN N INTO THE LOWER MISSISSIPPI RIVER 
VALLEY. UPSTREAM OF THIS RIDGE...A PERSISTENT NEGATIVE TILT 
UPPER TROUGH REMAINED ACROSS THE TROPICAL EPAC FROM NEAR 
10N115W TO ACROSS THE EQUATOR NEAR 105W. WEAK ANTICYCLONIC SHEAR 
ALOFT E OF THIS TROUGH CONTINUED TO PROVIDE A FAVORABLE 
ENVIRONMENT ALOFT FOR DEEP CONVECTION INVOF OF THE MONSOON 
TROUGH.  

AT THE SURFACE...1031 MB HIGH PRES IS JUST NW OF THE AREA NEAR 
31N144W WITH RIDGE AXIS EXTENDING SE TO THE MEXICAN COAST NEAR 
22N105W. A TIGHT PRES GRADIENT IS IN PLACE OVER THE W CENTRAL 
WATERS BETWEEN THIS RIDGE AND LOWER PRES ALONG THE EQUATOR. AS A 
RESULT FRESH TRADES ARE PRESENT IN THE AREAS FROM 09N TO 20N W 
OF 134W AND FROM 10N TO 16N BETWEEN 124W AND 134W...AS INDICATED 
BY RECENT ASCAT PASSES. THESE WINDS WILL PERSIST THROUGH THE 
EARLY PART OF THE WEEK ENCOMPASSING THE AREA FROM 08N TO 23N W 
OF 130W BY TUE NIGHT.

E OF THE RIDGE ALONG THE W COAST OF BAJA CALIFORNIA...WITH 
GRADIENT HAS WEAKENED SLIGHTLY...DIMINISHING WINDS TO THE 15-20 
KT RANGE ALONG THE OFFSHORE WATERS THERE. EXPECT FRESH WINDS TO 
RETURN N OF 28N E OF 121W BY MON EVENING AS THE HIGH SHIFTS E-NE 
AND THE PRES GRADIENT TIGHTENS OVER THE REGION. A COLD FRONT IS 
FORECAST TO DROP S OF 32N LATE MON INTO TUE...REACHING FROM 
29N114W TO 28N120W TO 29N128W BY TUE EVENING WITH FRESH 
NORTHERLY WINDS AND LARGE NW SWELLS BEHIND IT.

A WEAK INDUCED TROUGH CONTINUES FROM NEAR 16N105W TO 
10N110W...AND SEPARATES THE RIDGE TO THE NW WITH THE NE TO ELY 
WINDS CROSSING CENTRAL AMERICA AND SPILLING INTO THE EPAC. 
ABUNDANT MOISTURE CONTINUES TO BE TRAPPED BETWEEN 100W AND THE 
TROUGH...WITH SMALL CLUSTERS OF DEEP CONVECTION HAVING RECENTLY 
DEVELOPED OVER THE VERY WARM WATERS THERE N OF 12.5N. THIS 
TROUGH WILL CONTINUE TO WEAKEN OVER THE NEXT FEW DAYS AND 
DISSIPATE. 

OTHERWISE...LONG PERIOD NW SWELL YIELDING SEAS OF 8-11 FT WITH 
PEAK WAVE PERIODS OF 15-17 SECONDS COVERS THE WATERS W OF 100W. 
A NEW PULSE OF NW SWELL WILL ENTER THE NW WATERS MON NIGHT AND 
RAISE SEAS THERE TO NEAR 12 FT OVERNIGHT.

...GAP WINDS...
GALES IN THE GULF OF TEHUANTEPEC APPEAR TO HAVE ENDED AS ALL 
RECENT OBSERVATIONS SUGGEST WEAKENING WINDS. FRESH NLY WINDS 
ARE EXPECTED TO CONTINUE THIS MORNING BEFORE WILL DIMINISH TO 
LESS THAN 20 KT THIS AFTERNOON. 

FRESH TRADE WINDS IN THE SW CARIBBEAN WILL CONTINUE TO FUNNEL 
THROUGH THE PASSES OF CENTRAL AMERICA INTO AND DOWNWIND OF THE 
GULF OF PAPAGAYO AT 20-25 KT THROUGH TUE EVENING. THE STRONGEST 
WINDS WILL OCCUR DURING THE MORNING HOURS WITH THE AIDE OF 
ENHANCED DRAINAGE FLOW OFF THE THE ADJACENT LAND AREAS.

FRESH NORTHERLY WINDS WILL ALSO CONTINUE ACROSS THE GULF OF 
PANAMA THROUGH TUE EVENING.

$$
STRIPLING