000
AXPZ20 KNHC 031535
TWDEP 

TROPICAL WEATHER DISCUSSION
NWS NATIONAL HURRICANE CENTER MIAMI FL
1605 UTC SAT DEC 03 2011

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 1200 UTC SURFACE ANALYSIS AND SATELLITE IMAGERY THROUGH 
1500 UTC.

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

THE MONSOON TROUGH IS ALONG 09N83W TO 06N92W. THE INTERTROPICAL 
CONVERGENCE ZONE AXIS EXTENDS FROM 06N92W TO LOW PRES NEAR 
08N101W TO 06N111W TO 10N117W TO 10N125W TO 09N140W. ISOLATED 
MODERATE CONVECTION IS WITHIN 45 NM OF 10N126W.

...DISCUSSION...

A SHARP UPPER LEVEL TROUGH EXTENDS FROM SOUTHERN UTAH SW OVER 
THE NORTHERN BAJA INTO THE PACIFIC WATERS ALONG 31N116W TO A 
BASE NEAR 22N120W. OVERNIGHT REINFORCING SHORTWAVE ENERGY HAS 
DROPPED SOUTHWARD INTO THE BACK SIDE OF THE TROUGH...CARVING OUT 
A BROAD TROUGH BASE REMAINING N OF 20N E OF 133W. WATER VAPOR 
IMAGERY INDICATES VERY DRY AIR AND RELATIVELY STABLE CONDITIONS 
ALOFT WITH THIS UPPER LEVEL FEATURE. ELSEWHERE BROAD UPPER LEVEL 
RIDGES ARE FOUND BOTH TO THE W AND SE OF THE UPPER LEVEL 
TROUGHING...ONE WITH AN AXIS ALONG 136W AND THE OTHER CENTERED 
IN THE DEEP TROPICS NEAR 04N93W EXTENDING N-NE ACROSS MUCH OF 
CENTRAL AMERICA AND SOUTHERN MEXICO AND OVER THE GULF OF MEXICO.

HIGH PRESSURE IS FORECAST TO BUILD ACROSS THE GULF OF CALIFORNIA 
REGION FROM THE N TONIGHT INTO SUNDAY AND PRODUCE FRESH TO 
STRONG NORTHERLY WINDS...PERSISTING THROUGH MONDAY AFTERNOON AND 
NIGHT...POSSIBLY TO NEAR 30 KT.

HIGH PRESSURE WELL N OF THE AREA ACROSS THE FAR EASTERN NORTH 
PACIFIC EXTENDS S TO 18N BETWEEN 125W-150W ACROSS WESTERN 
PORTIONS OF THE DISCUSSION AREA...AND IS MAINTAINING FRESH NELY 
WINDS GENERALLY W OF 125W SOUTHWARD TO THE ITCZ ALONG ABOUT 08N. 
THIS WAS CONFIRMED BY EARLIER MORNING ASCAT PASSES AND A FEW 
SHIP OBSERVATIONS. SEAS OF 8 TO 12 FT PREVAIL ACROSS THIS AREA 
IN A MIX OF N AND NEW NW SWELL...AND BUILDING NE WIND WAVES. 
THIS WIND FLOW WILL DIMINISH AND VEER MORE NE TO E THROUGH 48 
HOURS AS HIGH PRES N OF THE AREA WEAKENS SLIGHTLY AND DRIFTS SE.

TO THE SE...A 1011 MB LOW PRES CENTER REMAINS EMBEDDED WITHIN 
THE ITCZ NEAR 08N101W AND IS MOVING W AT 10 KT. AN EARLIER ASCAT 
PASS AROUND 03/0420 UTC SHOWED 20 TO 25 KT WINDS WITHIN 150 NM 
ACROSS THE NRN SEMICIRCLE OF THE LOW PRES. GLOBAL MODELS SUGGEST 
SOME INCREASE IN SOUTHERLY FLOW INTO THE LOW THROUGH 24 HOURS... 
WITH THE LOW PERSISTING AT LEAST THROUGH 72 HOURS AS IT SHIFTS 
WNW AT AROUND 10 KT. THIS IS PLAUSIBLE THROUGH 48 HOURS GIVEN 
THAT THE LOW WILL MOVE INTO INTO THE FAVORABLE SE PORTION OF A 
BROAD UPPER LEVEL TROUGH TO THE N. THE UPPER LEVEL TROUGH 
AMPLIFIES BEYOND THAT...WITH THE LOW LIKELY WEAKENING. A LACK OF 
DEEP LAYER MOISTURE IS PREVENTING ANY MAJOR CONVECTIVE ACTIVITY 
NEAR THIS LOW PRES AREA PRESENTLY.

GULF OF TEHUANTEPEC...SCATTEROMETER PASSES DID NOT SAMPLE THE 
REGION WELL DURING THE OVERNIGHT HOURS...BUT WINDS ARE FORECAST 
BY ALL THE GLOBAL MODELS TO CONTINUE THROUGH ANOTHER 24 TO 30 
HOURS BEFORE DIMINISHING TO LESS THAN 20 KT.

GULF OF PAPAGAYO...OVERNIGHT DRAINAGE FLOW WILL ENHANCE THE N-NE 
FLOW CURRENTLY PREVAILING ACROSS THE WESTERN CARIBBEAN. FRESH TO 
STRONG NORTHEASTERLY GAP WINDS ARE EXPECTED DURING THE NEXT 
COUPLE OF DAYS...WITH WINDS LIKELY STRONGEST DURING THE LATE 
NIGHT AND EARLY MORNING HOURS. 

$$
HUFFMAN