000
AXPZ20 KNHC 260328
TWDEP 

TROPICAL WEATHER DISCUSSION 
NWS TPC/NATIONAL HURRICANE CENTER MIAMI FL
0405 UTC MON OCT 26 2009

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

BASED ON 0000 UTC SURFACE ANALYSIS AND SATELLITE IMAGERY THROUGH 
0245 UTC.

...ITCZ...

THE INTERTROPICAL CONVERGENCE ZONE IS CENTERED ALONG 9N84W TO 
8N92W TO 12N104W TO 8N124W TO 10N118W TO 9N140W. SCATTERED STRONG
CONVECTION WAS WITHIN 120 NM S OF THE AXIS BETWEEN 129W-133W.
SCATTERED MODERATE TO STRONG CONVECTION WAS WITHIN 60 NM S OF THE
AXIS BETWEEN 104W-107W...AND BETWEEN 123W-125W. SCATTERED 
MODERATE/ISOLATED STRONG CONVECTION WAS WITHIN 60 NM OF THE AXIS 
BETWEEN 110W-112W. SCATTERED MODERATE CONVECTION WAS WITHIN 60 
NM S OF THE AXIS BETWEEN 91W-93W.

...DISCUSSION...

A LONGWAVE TROUGH THAT EXTENDED FROM WESTERN TEXAS SW TO ACROSS
SOUTHERN BAJA CALIFORNIA AND TO NEAR 20N124W WILL BE RE-ENFORCED
BY SHORTWAVE ENERGY FROM THE PACIFIC NW THAT WILL DIVE S INTO 
THE BACKSIDE OF THE TROUGH OVER THE NEXT 24-36 HOURS AND AMPLIFY 
THE TROUGH OVER THE S CENTRAL U.S. WITHIN THE NEXT 24-36 HOURS.
THE ASSOCIATED SURFACE FRONT DISSIPATED OVER SE MEXICO AND FAR 
SW GULF OF MEXICO THIS AFTERNOON. THE TROUGH IS FORECAST TO 
RAPIDLY MOVE E AND THEN NE THROUGH THE NEXT 24-36 HOURS. A 
SECONDARY COLD FRONT ASSOCIATED WITH THE REINFORCING SHORTWAVE 
ENERGY IS CURRENTLY PASSING S THROUGH THE GREAT BASIN AND SHOULD 
MOVE INTO NORTHERN MEXICO BY EARLY MON MORNING. LATEST MODEL 
RUNS HINT
AT INCREASING SW WINDS IN THE FAR NORTHERN GULF OF CALIFORNIA N 
OF ABOUT 30N BEGINNING TUE AFTERNOON INTO TUE EVENING AS SURFACE
LOW PRES DEEPENS OVER THE SW U.S. WITH THE SECOND SHOT OF 
SHORTWAVE ENERGY AND INTERACTS WITH STRENGTHENING RIDGING OVER 
THE E PACIFIC WATERS. WILL HOLD OFF FORECASTING THIS EVENT FOR 
THE 0000 UTC HIGH SEAS SINCE IT APPEARS THAT IF THIS EVENT DOES 
OCCUR IT WILL BE RATHER BRIEF.

TO THE S OF THE LONGWAVE TROUGH...A JET STREAM BRANCH WITH 
MAXIMUM JET CORE WINDS OF 60-90 KT WAS ADVECTING UPPER LEVEL 
MOISTURE IN THE FORM OF BROKEN CIRRUS CLOUDS ENE TOWARDS MEXICO 
FROM 16N TO 19N. A SURFACE TROUGH IN THE VICINITY OF THE REAR 
RIGHT QUADRANT OF THE JET EXTENDS FROM 11N113W TO 15N110W. WITH
LOW LEVEL CONVERGENCE NEAR THE THROUGH IN ADDITION TO UPPER 
LEVEL DIFFLUENCE WITHIN THIS AREA...ITCZ CONVECTION WILL REMAIN 
RATHER ENHANCED HERE THROUGH THE NEXT 48 HOURS AND POSSIBLY 
BEYOND. IN FACT...THE LATEST RUN OF THE GLOBAL MODELS SUGGESTED 
THAT BROAD LOW PRES IN THE FORM OF A GYRE WILL LINGER THROUGHOUT 
THIS AREA AS WELL. THE MEAN ENSEMBLES OF BOTH THE GFS AND 
EUROPEAN MODELS HAVE HINTED AT A LOW EMERGING FROM THIS GYRE WITH
A TRACK TO THE NE. WILL ANALYZE FUTURE MODELS TRENDS AND 
ENSEMBLES TO SEE WHAT DEFINITIVE LOW PRES WILL POSSIBLY DEVELOP. 
AS FOR STRENGTH OF THE POSSIBLE LOW...PRESENTLY IT IS TOO EARLY
CONFIRM THIS BASED ON AVAILABLE MODEL DATA.

OVER THE WESTERN AND CENTRAL SECTIONS OF THE AREA...HIGH PRES 
REMAINS IN PLACE AS A MID/UPPER LEVEL RIDGE CREST SPILLING SE 
EXTENDS FROM 32N133W WELL NE TO THE PACIFIC NW COAST. AT THE 
SURFACE...A NEARLY STATIONARY 1027 MB HIGH CENTER IS ANALYZED N 
OF 
THE AREA NEAR 35N136W WITH A RIDGE SE TO 23N124W. HIGH PRES 
GENERALLY COVERS THE AREA N OF 20N AND W OF 120W. THE PRES 
DIFFERENCE BETWEEN THE RIDGE AND LOW PRES OVER THE WESTERN U.S. 
IS ALLOWING FOR NE-E WINDS OF 20-25 KT N OF 26N AND W OF 130W 
WITH SEAS 8-10 FT...AND N-NE 20 KT WINDS N OF 26N BETWEEN 122W
-130W. NE-E TRADE WINDS OF 20 KT WERE NOTED ON THE S SIDE OF THE 
RIDGE AXIS. THE RIDGE IS FORECAST TO STRENGTHEN THROUGH THE NEXT 
48 HOURS AS THE PARENT HIGH TO THE N INTENSIFIES. LONG PERIOD 
NW-N SWELLS PRODUCING SEAS OF UP TO 16 FT AS PER LATEST WAVEWATCH
GUIDANCE ARE EXPECTED TO FILTER INTO THE FAR NE PORTION OF THE 
AREA BY TUE NIGHT WITH NW-N WINDS THERE INCREASING TO 20-30 KT 
AS INDICATED BY THE GLOBAL MODELS.

SCATTERED TO BROKEN STRATOCUMULUS CLOUDS MOVING IN GENERAL 
WESTWARD
DIRECTION WERE OBSERVED TO THE N OF 15N AND W OF 130W INDICATIVE 
OF A VERY STABLE BROAD SCALE ENVIRONMENT ACROSS THIS AREA AS WAS 
FURTHER SUPPORTED BY WIDESPREAD MODERATE SUBSIDENCE AS NOTED IN 
SATELLITE WATER VAPOR IMAGERY.

OVER THE EASTERN SECTION...A BATCH OF LOW TO MID LEVEL MOISTURE 
DROPPING
S BEHIND IN THE WAKE OF THE LONGWAVE TROUGH WAS NOTED AS A 
BLANKET
OVERCAST STRATOCUMULUS CLOUDS N OF 24N BETWEEN 115W-120W. HOWEVER
...THESE CLOUDS SHOULD ERODE OVER THE NEXT 6-12 HOURS AS 
SURROUNDING SUBSIDENT AIR IS ENTRAINED INTO THEM. A MID/UPPER 
LEVEL NEARLY STATIONARY ANTICYCLONE NEAR 4N112W EXTENDS A RIDGE 
NEWD TO 10N101W AND FURTHER NE TO ACROSS FAR SE MEXICO. STRONG 
UPPER LEVEL DIFFLUENCE WAS NOTED NE OF THE ANTICYCLONE WAS 
AIDING ITCZ CONVECTION BETWEEN 103W AND 114W. UPPER LEVEL DEBRIS 
CLOUDS IN THE FORM OF CIRRUS STRANDS WERE SPREADING NE AND 
MERGING WITH THE UPPER LEVEL MOISTURE THAT WAS ASSOCIATED WITH 
THE JET STREAM DESCRIBED EARLIER.

$$
AGUIRRE