000
AXPZ20 KNHC 130909
TWDEP 

TROPICAL WEATHER DISCUSSION  
NWS NATIONAL HURRICANE CENTER MIAMI FL
1005 UTC SUN FEB 13 2011

TROPICAL WEATHER DISCUSSION FOR THE EASTERN PACIFIC OCEAN FROM 
THE EQUATOR TO 32N...EAST OF 140W.

BASED ON 0600 UTC SURFACE ANALYSIS AND SATELLITE IMAGERY THROUGH 
0715 UTC.

...ITCZ...

THE INTERTROPICAL CONVERGENCE ZONE AXIS ANALYZED FROM 04N77W TO 
02N105W TO 05N122W TO 07N135W TO 06N140W. SCATTERED MODERATE TO 
STRONG CONVECTION IS WITHIN 120 NM S OF THE ITCZ AXIS E OF 79W. 
A TROUGH IS EMBEDDED IN THE ITCZ FROM 11N123W TO 05N126W AND 
SCATTERED MODERATE CONVECTION LIES WITHIN 180 NM E OF THE TROUGH 
FROM 08N TO 10N.

...DISCUSSION...

THE LONGWAVE UPPER PATTERN OVER THE FORECAST AREA IS EXPECTED TO 
CHANGE LITTLE OVER THE NEXT FEW DAYS WITH UPPER LEVEL RIDGING 
CENTERED ALONG 107W AND TROUGHING CENTERED ALONG 133W. THE 
AMPLIFIED TROUGH CURRENTLY ALONG 133W IS FORECAST TO WEAKEN OVER 
THE FORECAST AREA TODAY AS THE SHORTWAVE ENERGY WITHIN THE 
TROUGH BECOMES DISLODGED NORTHEASTWARD INTO THE SW CONUS AND 
OVER THE UPPER RIDGE BY A LOW TO MID LEVEL LOW ON THE LEADING 
EDGE OF A BROAD NORTHERN STREAM TROUGH APPROACHING THE AREA FROM 
THE NW. A SOUTH TO SOUTHWESTERLY JET WITH WINDS IN THE 40 TO 60 
KT RANGE AHEAD OF THE AMPLIFIED UPPER TROUGH IS TRANSPORTING 
MOISTURE ALOFT TOWARD BAJA CALIFORNIA PRIMARILY IN THE FORM OF 
CIRRUS CLOUDS WHILE SCATTERED MODERATE CONVECTION CAN BE FOUND 
UNDER THE REAR RIGHT QUADRANT OF THE JET NEAR A SURFACE TROUGH 
IN THE ITCZ MENTIONED ABOVE. THIS TROUGH LIES UNDER A REGION OF 
BROAD UPPER LEVEL DIFFLUENCE BETWEEN THE UPPER TROUGH AND RIDGE 
AXES AND WITHIN A REGION OF RELATIVELY HIGH PRECIPITABLE WATER 
VALUES. THE CHANCE OF PRECIPITATION WILL DECREASE HERE AS THIS 
UPPER TROUGHING WEAKENS. THE MID TO LOW LEVEL LOW IS ASSOCIATED 
WITH A COLD FRONT AT THE SURFACE CURRENTLY OVER FAR NW WATERS. 
THE 0250Z WINDSAT PASS SHOWS THE STRONGEST WINDS ARE TO 25 KT IN 
THE NW FLOW BEHIND THE FRONT WHILE SHIP ZCDA9 CONFIRMS S WINDS 
TO 20 KT WITHIN 180 NM AHEAD OF THE FRONT AND THE 0340Z JASON2 
PASS SHOWS SEAS AS HIGH AS 11 FT IN NW WATERS. THIS FRONT WILL 
WEAKEN AS IT GRADUALLY MOVES E ACROSS N WATERS THROUGH TUE 
MORNING...BUT THE INCOMING BROAD TROUGH WILL SUPPLY A 
REINFORCING SHOT OF COOLER AIR TO THE AREA JUST AFTER THE 
FORECAST PERIOD ON TUE. FRESH TRADES FROM 08N TO 18N W OF 118W 
WILL SHIFT SLIGHTLY SW BY TONIGHT AND INTENSIFY BY TUE MORNING 
IN RESPONSE TO THE SOUTHWARD SHIFTING HIGH PRES E OF THE COLD 
FRONT THAT IS EXPECTED TO STRENGTHEN SLIGHTLY BY THE END OF THE 
PERIOD EARLY TUE.

GAP WINDS...
GULF OF TEHUANTEPEC...HIGH PRES THAT WAS OVER SE TEXAS SAT HAS 
SHIFTED INTO THE NW GULF OF MEXICO AND IS FORCING A REINFORCING 
SURGE OF COLD AIR THROUGH THE PASS. A STORM WARNING IS IN PLACE 
NOW THROUGH THIS AFTERNOON. A SLIGHT LESSENING OF THE GRADIENT 
LATER TODAY SHOULD ALLOW FOR THE WINDS TO DIMINISH BELOW 50 KT 
WHILE CONTINUED WEAKENING OF THE GRADIENT WILL DROP WINDS BELOW 
GALE FORCE BY SUN AFTERNOON. SEAS WILL BUILD TO THE 17 TO 19 FT 
RANGE COINCIDENT WITH THE STORM FORCE CONDITIONS. NE SWELL 
GENERATED BY THESE WINDS WILL SPREAD SE THROUGH THE 
PERIOD...MEETING UP WITH CROSS-EQUATORIAL SW SWELL SUN AFTERNOON 
WITH SEAS 8 FT OR GREATER FROM DOWNWIND OF TEHUANTEPEC TO THE 
EQUATOR BY TUE MORNING.

GULFS OF PAPAGAYO AND FONSECA...THE 0342Z ASCAT PASS SHOWS NE TO 
E WINDS TO 25 KT DOWNWIND OF THE GULF OF PAPAGAYO AND 20 KT N TO 
NE WINDS DOWNWIND OF THE GULF OF FONSECA. THE OBSERVATION AT THE 
EL SALVADOR INTERNATIONAL AIRPORT UPWIND OF THE GULF OF FONSECA 
SHOWED FRESH N TO NE WINDS BETWEEN 03Z AND 06Z THIS MORNING. 
WINDS NEAR FONSECA ARE EXPECTED TO DIMINISH BELOW 20 KT MON AS 
THE PRES GRADIENT OVER CENTRAL AMERICA WEAKENS...BUT WINDS ARE 
EXPECTED TO REMAIN IN THE 20 TO 25 KT RANGE IN PAPAGAYO THROUGH 
THE PERIOD ESPECIALLY AS COOL DRAINAGE FLOW INCREASES WINDS IN 
THE EARLY MORNING HOURS. 

GULF OF PANAMA...NE TRADE WINDS TO 20 KT ARE FILTERING ACROSS THE
ISTHMUS OF PANAMA AND BECOMING NLY ACROSS THE GULF OF PANAMA N 
OF 06N BETWEEN 78W AND 80W AS CONFIRMED BY SHIP ZCDGS OVER THE 
PAST SEVERAL HOURS. WINDS HERE ARE EXPECTED TO DIMINISH BELOW 
ADVISORY CRITERIA BY MON AFTERNOON.

GULF OF CALIFORNIA...THERE HAVE BEEN NO NEW OBSERVATIONS OVER 
THE PAST 8 HOURS TO CONFIRM THE EXISTENCE OF 20 KT WINDS IN THE 
GULF OF CALIFORNIA. HOWEVER...IT IS BELIEVED THAT THE PRES 
GRADIENT BETWEEN HIGH PRES OVER THE U.S. INTERMOUNTAIN WEST AND 
A BROAD SURFACE TROUGH OVER NW MEXICO CONTINUES TO GENERATE 20 
NW WINDS THAT ARE FUNNELING THROUGH THE N HALF OF THE GULF OF 
CALIFORNIA. THESE WINDS ARE EXPECTED TO DIMINISH BELOW 20 KT 
LATER THIS MORNING AS THE GRADIENT RELAXES.

$$
SCHAUER