000
AXPZ20 KNHC 282206
TWDEP 

TROPICAL WEATHER DISCUSSION   
NWS TPC/NATIONAL HURRICANE CENTER MIAMI FL
2205 UTC WED JAN 28 2009

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

BASED ON 1800 UTC SURFACE ANALYSIS AND SATELLITE IMAGERY THROUGH 
2145 UTC.

...ITCZ...

ITCZ AXIS IS CENTERED ALONG 4N78W 4N89W 2N100W 1N100W 1N120W
1N130W 2N140W. NO SIGNIFICANT CONVECTION IS NOTED.

...DISCUSSION...

THE TAIL END OF A DEEP LAYER TROUGH EXTENDS FROM CENTRAL 
CALIFORNIA SW INTO THE AREA THROUGH 32N125W TO NEAR 29N129W. TO 
ITS W...A DIFFUSING ELONGATED MID/UPPER CYCLONIC CIRCULATION IS 
NEAR 28N136W WITH AN ASSOCIATED TROUGH STRETCHING SEWD TO 
25N133W TO 20N129W THEN SHARPENS AS ITS EXTENDS TO 15N126W TO 
11N122W TO NEAR 7N120W. THESE FEATURES ARE ON THE SOUTHERN 
PERIPHERY OF A LARGE ENVELOPE OF UPPER LEVEL RIDGING THAT 
EXTENDS WELL N OF THE AREA WITH AN ASSOCIATED DEEP LAYERED 
ANTICYCLONE MOVING NE AND CENTERED NEAR 40.5N138W. A JET STREAM 
BRANCH WITH MAXIMUM WINDS OF 60-80 KT ROUNDS THE ABOVE TROUGH 
AXIS FROM 17N134W THROUGH 24N125W TO 27N121W AND NE ACROSS 
CENTRAL BAJA CALIFORNIA TO OVER NORTHERN MEXICO. THIS JET 
CONTINUES TO ADVECT SCATTERED TO BROKEN HIGH LEVEL CLOUDS FROM 
CENTRAL TROPICAL PACIFIC REGION NE TO ACROSS MUCH OF BAJA 
CALIFORNIA AND NRN MEXICO.

THE WEAKENING MID/UPPER LEVEL CYCLONIC CIRCULATION IS FORECAST 
TO LIFT N AND BECOME ABSORBED INTO A RATHER VIGOROUS LONGWAVE
TROUGH CURRENTLY NW OF THE AREA DURING THE NEXT 18-24 HOURS. THE
ANTICYCLONE LOCATED WELL N OF THE AREA NEAR 40.5N138W IS THEN
PUSHED ESE WHILE WEAKENING THROUGH FRI BY THE TROUGH. A SURFACE
COLD FRONT ASSOCIATED WITH THIS TROUGH IS FORECAST TO STAY N OF
THE REGION OVER THE NEXT 48 HOURS AS WEAKER HIGH PRES BOTH AT THE
SURFACE AND ALOFT RE-ESTABLISHES ITSELF OVER THE NRN SECTION OF
THE AREA.

TO THE SE OF THE ABOVE MENTIONED MID/UPPER TROUGH AND ASSOCIATE
JET STREAM BROAD MID/UPPER LEVEL RIDGING DOMINATES THE AREA...
NAMELY THE ERN PORTION WITH AN ASSOCIATED NEARLY STATIONARY 
ANTICYCLONE NEAR 7N90W. THIS PATTERN CONTINUES TO RESULT IN 
MODERATE TO STRONG SUBSIDENCE WITH VERY DRY STABLE AIR E OF 
ABOUT 120W WHERE...WITH THE EXCEPTION OF SCATTERED LOW CLOUDS 
WITH ISOLATED SHOWERS MOVING W...SKIES ARE MOSTLY CLEAR. THESE 
CONDITIONS ARE EXPECTED TO LAST OVER THE NEXT 48 HOURS AS THE 
AREA OF MID/UPPER RIDGING HOLDS ACROSS THIS AREA.

A TIGHT PRES GRADIENT N OF 20N W OF 122W IS BRINGING NE-E 20-25 
KT WINDS TO THOSE WATERS WITH SEAS IN THE 10-14 FT IN E SWELL.
THESE WINDS DIMINISH TO NE-E 20 KT IN 48 HOURS WITH SEAS TO 8 
FT.

NE GULF OF PAPAGAYO WINDS IN THE RANGE OF 20 KT ARE FORECAST TO 
IN INCREASE SOME IN 24 HOURS...THEN DIMINISH TO JUST NEAR 20 KT
IN 48 HOURS AS SW CARIBBEAN TRADES WEAKEN DUE TO A LIGHTER PRES 
GRADIENT.

$$
AGUIRRE