000
AXPZ20 KNHC 251031 AAA
TWDEP 

TROPICAL WEATHER DISCUSSION...UPDATED
NWS NATIONAL HURRICANE CENTER MIAMI FL
1005 UTC TUE DEC 25 2012

UPDATED SATELLITE IMAGERY TIME

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 
1015 UTC.

...INTERTROPICAL CONVERGENCE ZONE/MONSOON TROUGH...
THE MONSOON TROUGH EXTENDS FROM 07N78W TO 09N85W TO 06N94W WHERE 
LOW LEVEL WINDS SUGGEST IT TRANSITIONS TO THE ITCZ TO 09N107W TO 
08N122W TO 09N127W TO 06N140W. NUMEROUS STRONG CONVECTION IS
ALONG AND WITHIN 30 NM OF THE TROUGH BETWEEN 78W-90W. SCATTERED 
MODERATE/ISOLATED STRONG CONVECTION IS WITHIN 120 NM N OF THE  
ITCZ BETWEEN 126W-129W...AND ALSO FROM 09N TO 11N BETWEEN 
120W-122W. SCATTERED MODERATE CONVECTION IS WITHIN 30 NM OF THE
ITCZ BETWEEN 129W-136W.

...DISCUSSION...

A LONGWAVE TROUGH EXTENDS FROM THE CENTRAL U.S. PORTIONS SSW TO 
CENTRAL MEXICO...AND SW TO 22N126W TO A DEVELOPING UPPER LOW AT 
16N135W AND S TO NEAR 02N135W. A LARGE UPPER RIDGE OVER THE FAR 
NE PORTION IS AMPLIFYING WHILE IT SLIDES EASTWARD IN RESPONSE TO 
A RATHER VIGOROUS UPPER TROUGH WELL N OF THE AREA ALONG 135W. 
BROAD MID/UPPER LEVEL RIDGING COVERS THE AREA TO THE W AND NW OF 
THE LONGWAVE TROUGH. FAST UPPER LEVEL WSW WINDS BETWEEN IT AND 
THE UPPER TROUGH TO THE N ARE ADVECTING EXTENSIVE UPPER LEVEL 
MOISTURE IN THE FORM OF MOSTLY OVERCAST MID AND UPPER LEVEL 
CLOUDS E AND NE AROUND THE NRN CREST OF THE RIDGE. THIS MOISTURE 
HAS A TRAJECTORY THAT CARRIES IT TOWARDS CALIFORNIA AND THE U.S. 
W COAST. MODERATE SUBSIDENCE IN THE UPPER LEVELS OVER MUCH OF 
THE AREA WHERE THE RIDGE IS IN PLACE IS ALLOWING FOR DRY AND 
STABLE ATMOSPHERIC CONDITIONS THERE WITH JUST PATCHES OF 
STRATOCUMULUS CLOUDS MOVING WESTWARD WITH POSSIBLE ISOLATED 
SHOWERS. AT THE SURFACE...THE SOUTHERN PORTION OF A COLD FRONT 
SUPPORTED BY THE UPPER TROUGH IS ANALYZED JUST TO THE NW OF THE 
DISCUSSION AREA...WHILE A 1026 MB HIGH CENTER IS AT 28N136W WITH 
A RIDGE SE TO NEAR 21N115W.

TO THE SE OF THE LONGWAVE TROUGH BROAD ANTICYCLONIC FLOW IS 
PRESENT OVER THAT PART OF THE AREA. A JET STREAM BRANCH EXTENDS 
FROM 18N125W TO 22N115W TO ACROSS FAR SRN BAJA CALIFORNIA TO 
INLAND CENTRAL MEXICO. SCATTERED TO BROKEN HIGH CLOUDS ARE 
WITHIN 180 NM OF THE JET. AN ANTICYCLONE OVER THE BORDER OF 
HONDURAS/NICARAGUA IS SLOWLY MOVING E. AN UPPER LEVEL TROUGH TO 
ITS SE FROM 08N85W TO 03N81W IS HELPING TO TRIGGER OFF 
CONVECTION ALONG AND NEAR THE FAR E END OF THE MONSOON TROUGH AS 
DESCRIBED ABOVE.THIS TROUGH WILL MOVE LITTLE TO THE E THROUGH 
WED AS IT BECOMES LESS DISCERNIBLE.

CONVECTION REMAINS ACTIVE ALONG THE ITCZ BETWEEN 126W-129W AHEAD
OF THE UPPER LOW AND TROUGH WHERE DIVERGENCE IS PRESENT. THE 
UPPER TROUGH N OF THE AREA WILL MOVE INLAND THE U.S. W COAST WED 
WITH THE UPPER LOW AT 16N135W LIFTING NE AND BECOMING DIFFUSE. 
THE UPPER FLOW PATTERN THAN BECOMES GENERALLY MORE ZONAL ACROSS 
THE NRN AND CENTRAL PORTIONS THROUGH WED. WITH THIS TAKING 
PLACE...THE SURFACE HIGH OF 1026 MB DISSIPATES WED AS THE COLD 
FRONT JUST NW OF THE AREA QUICKLY MOVES E TO INLAND SRN 
CALIFORNIA WHILE WEAKENING. BEFORE MOVING INLAND...THE FRONT 
WILL USHER IN NW WINDS OF 20 TO 25 KT OVER THE EXTREME NE 
PORTION BY LATE WED.

THE OVERNIGHT ASCAT PASSES FROM 0536 UTC AND 0718 UTC REVEALED
FRESH TO STRONG TRADES S OF THE SURFACE HIGH PRES RIDGE...FROM 
ABOUT 07N TO 20N W OF 120W. JASON ALTIMETRY DATA FROM THE PAST 
18 HOURS CONFIRMED GLOBAL WAVE MODEL FORECASTS DEPICTING A BROAD 
AREA OF SEAS FROM 9 TO 11 FT WITHIN THIS AREA OF TRADES. THIS 
AREA OF TRADES IS FORECAST TO SHRINK SLIGHTLY OVER THE NEXT 
24-48 HRS.

STRONGER HIGH PRES IS FORECAST TO BUILD ESE ACROSS MUCH OF THE 
AREA ON WED KICKING UP THE TRADE WINDS FROM 08N TO 20N W OF 
124W. GLOBAL WAVE MODEL GUIDANCES SUGGEST THAT NW SWELLS WILL
PUSHING INTO THE NW PART OF THE AREA ON WED.

GULF OF TEHUANTEPEC...A BRIEF GAP EVENT IS IN STORE FOR THE GULF
LATER THIS WEEK AS A COLD FRONT PUSHES THROUGH THE GULF OF 
MEXICO. THE FRONT WILL BE FOLLOWED BY A SURGE OF COLDER AND 
DRIER AIR DOWN THE COAST OF MEXICO...FUNNELING THROUGH THE 
CHIVELA PASS AND THROUGH THE ISTHMUS OF TEHUANTEPEC BEGINNING 
EARLY WED EVENING. A GALE WARNING HAS BEEN POSTED FOR THE GULF 
OF TEHUANTEPEC STARTING 27/00 UTC...AND FORECAST TO LAST FOR 6 
HRS.
 
$$
AGUIRRE