000
AXPZ20 KNHC 292148
TWDEP 

TROPICAL WEATHER DISCUSSION
NWS TPC/NATIONAL HURRICANE CENTER MIAMI FL
2205 UTC THU NOV 29 2007

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 
2130 UTC.
 
...ITCZ...

ITCZ AXIS IS CENTERED ALONG 6N77W 6N95W 14N120W 9N130W 8N140W. 
SCATTERED MODERATE ISOLATED STRONG FROM 9N TO 20N BETWEEN 107W 
AND 122W. 

...DISCUSSION...

E OF 110W...
A STRONG MID-LEVEL HIGH IS CENTERED OVER THE SE GULF OF MEXICO 
WITH AN UPPER RIDGE AXIS EXTENDING NWWD FROM NORTHERN COLOMBIA 
NW TO THE TEXAS/MEXICO BORDER. DUE TO THE RIDGE...THE FLOW ALOFT 
E OF 100W IS PRIMARILY SOUTHERLY BUT A LACK OF MOISTURE S OF THE 
EQUATOR IS PRODUCING MAINLY DRY AIR NEAR CENTRAL AMERICA. 
SPORADIC DEEP CONVECTION IS OCCURRING ALONG THE ITCZ E OF 
110W...BUT THE LOW-LEVEL ENVIRONMENT N OF THE AXIS IS ALSO 
RATHER DRY. A MODEST GAP WIND EVENT IS OCCURRING OVER THE GULF 
OF TEHUANTEPEC AND GULF OF PAPAGAYO BUT BOTH ARE EXPECTED TO 
REMAIN BELOW GALE CRITERIA. ELSEWHERE...A SHEARED UPPER LEVEL 
SHORTWAVE TROUGH IS LOCATED ALONG 101W OVER CENTRAL MEXICO AND 
THE ADJACENT WATERS...PRODUCING ADDITIONAL SUBSIDENCE OVER THE 
AREA N OF 15N E OF 104W.

W OF 110W...
THE MAJOR WEATHER MAKER OVER THE SUBTROPICAL PACIFIC WATERS IS 
A PERSISTENT AND LARGE CUT-OFF LOW CENTERED W OF BAJA CALIFORNIA 
NEAR 26N125W WHICH IS EXPECTED TO REMAIN NEARLY STATIONARY FOR 
ANOTHER 24 HRS OR SO...THEN LIFT NE AND BECOME ABSORBED BY A 
LARGER UPPER TROUGH OVER THE WESTERN UNITED STATES. STRONG UPPER 
DIFFLUENCE IS OCCURRING SE OF THE LOW WHERE PART OF THE FLOW 
TURNS NE INTO NW MEXICO AND THE OTHER PART TURNS SE PAST THE 
EQUATOR. THIS HAS CAUSED SURFACE PRESSURES TO LOWER IN THE AREA 
WITH A 1013 MB SURFACE LOW NEAR 25N121W ALONG A TROUGH EXTENDING 
FROM THE LOW TO 12N124W. THE LOW IS EXPECTED TO LIFT NE INTO 
SOUTHERN CALIFORNIA AND ARIZONA BY SAT MORNING. THERE IS THE 
POTENTIAL FOR SIGNIFICANT RAINFALL OVER PARTS OF BAJA 
CALIFORNIA...SONORA...SINALOA...AND CHIHUAHUA THROUGH SAT DUE TO 
THE DEEP PLUME OF MOISTURE THAT WILL STREAM IN FROM THE SOUTH. 
THEREAFTER...THE LOW WILL LIKELY CONTRIBUTE TO A SIGNIFICANT 
WINTER STORM OVER PARTS OF THE ROCKIES AND CENTRAL PLAINS EARLY 
NEXT WEEK.

ELSEWHERE...MODERATE/STRONG SUBSIDENCE IS OCCURRING ON THE BACK 
SIDE OF THE CUT-OFF LOW WHERE THE FLOW IS CONVERGING INTO THE 
BASE OF THE TROUGH. THERE IS VERY LITTLE CLOUD COVER AT THE 
MOMENT AND THE TRADES ARE ACTUALLY EXPECTED TO WEAKEN OVER THE 
NEXT FEW DAYS AS LOW PRES DEVELOPS TO THE E AND BREAKS DOWN THE 
RIDGE.
  
$$
COBB