000
AXPZ20 KNHC 171608
TWDEP 

TROPICAL WEATHER DISCUSSION
NWS TPC/NATIONAL HURRICANE CENTER MIAMI FL
1605 UTC THU JAN 17 2008

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

BASED ON 1200 UTC SURFACE ANALYSIS AND SATELLITE IMAGERY THROUGH 
1545 UTC.
 
...ITCZ...

ITCZ AXIS IS CENTERED ALONG 5N78W 5N90W 6N100W 7N110W 8N120W
5N130W 4N140W. SCATTERED MODERATE CONVECTION IS WITHIN 30 NM 
EITHER SIDE OF THE AXIS BETWEEN 78W-82W.

...DISCUSSION...

A VERY PRONOUNCED LONGWAVE TROUGH EXTENDS FROM THE SOUTHWEST 
UNITED STATES SOUTHWEST ACROSS NORTHERN BAJA CALIFORNIA...AND
WESTWARD THROUGH 30N121W TO 30N126W. AN EMBEDDED SHORTWAVE 
TROUGH IS SWINGING SOUTHEASTWARD ACROSS SOUTHWEST ARIZONA AND 
NORTHERN BAJA CALIFORNIA TO 25N118W. A 200 NM WIDE AREA OF 
MODERATE SUBSIDENCE IS NOTED 28N114W TO 28N120W AND THEN NW 
TO 30N125W. TO THE NORTHWEST OF THE LONGWAVE...A MID/UPPER LEVEL
ANTICYCLONE IS WELL NORTH OF THE REGION NEAR 44N132W. THE FLOW
PATTERN BETWEEN THE TROUGH AND THE HIGH IS NLY CHANNELING 
ABUNDANT HIGH LEVEL MOISTURE SWD ALONG THE WEST COAST OF THE 
UNITED STATES SOUTHWARD TO INTO THE FAR NORTHEAST CORNER OF THE 
REGION.

W OF THE TROUGH...BROAD MID/UPPER LEVEL RIDGING IS DEFINED TO 
THE W OF 115W WITH A RIDGE AXIS ROUGHLY ALONG 130W. THE LONGWAVE
TROUGH IS FORECAST TO GRADUALLY SHIFT EASTWARD OVER THE NEXT
NEXT FEW DAYS AND FLATTEN AS THE BROAD SCALE FLOW BECOMES WLY 
OVER THE REGION AND SW UNITED STATES. LITTLE IN THE WAY OF ANY 
DEEP CONVECTION IS OBSERVED OVER THE FAR ERN PART OF THE PACIFIC 
IN THE VICINITY OF THE TROUGH DUE TO THE SUBSIDENCE PRESENT N OF 
21N E OF 120W. WIDELY SCATTERED MODERATE CONVECTION NOTED FROM
11N1-15N BETWEEN 104W-108W IS DUE TO A SHORTWAVE TROUGH EXTENDING
FROM 6N100W NORTHWEST THROUGH 12N103W TO 21N111W. CONVECTION
...HOWEVER...IS EXPECTED TO REMAIN RATHER MINIMAL AS IT 
ENCOUNTERS VERY DRY AIR TO ITS EAST. THE TROUGH IS FORECAST TO 
LIFT NORTHEAST TOWARDS MEXICO OVER THE NEXT 3 DAYS. STRONG HIGH 
PRES CENTERED OVER THE WESTERN UNITED STATES IN COMBINATION WITH 
LOW PRES OVER NORTHWEST MEXICO HAS PROMPTED A GALE WARNING TO BE 
ISSUED FOR THE NORTHERN SECTION OF THE GULF OF CALIFORNIA N OF 
28N WHERE WINDS ARE FORECAST TO REACH UP TO 40 KT THROUGH EARLY 
THIS EVENING. THESE WINDS WILL ALSO CONTINUE TO KICK UP SAND AND 
DUST FROM THE MOJAVE DESERT. ELSEWHERE ACROSS THE GULF OF 
CALIFORNIA WINDS WILL BE NW 20-25 KT DECREASING TO 20 KT IN 48 
HRS.

AT THE SURFACE...STRONG RIDGING EXTENDS FROM 32N133W SOUTHEAST
TO 27N126W AND 22N121W. HIGH PRES COVERS THE AREA N OF 20N AND W 
OF 110W. A WEAK SURFACE TROUGH MOVING W EXTENDS FROM 10N125W TO
5N126W ...AND IS PRODUCING SCATTERED TO BROKEN LOW CLOUDS WITH 
ISOLATED SHOWERS FROM 10N-11N BETWEEN 121.5W-125W. BROKEN LOW
AND MID LEVEL CLOUDS WITH ISOLATED WEAK CONVECTION ARE NOTED
FROM 11N-18N W OF 124W.

GAP WINDS...EXPECT GULF OF PAPAGAYO NE 20 KT WINDS TO BEGIN EARLY
THIS AFTERNOON AND LAST INTO EARLY NEXT WEEK WITH INTERMITTENT
PERIODS OF THESE WINDS DECREASING TO BELOW 20 KT. THE NEXT GALE
EVENT IS EXPECTED TO BEGIN IN THE GULF OF TEHUANTEPEC LATE SUN 
DUE TO STRONG HIGH PRES THAT BUILDS SOUTHWARD OVER CENTRAL AND 
SOUTHEASTERN MEXICO.

$$
AGUIRRE