000
AXPZ20 KNHC 181516
TWDEP 

TROPICAL WEATHER DISCUSSION
NWS TPC/NATIONAL HURRICANE CENTER MIAMI FL
1605 UTC FRI DEC 18 2009

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 
1500 UTC.

...ITCZ...

THE INTERTROPICAL CONVERGENCE ZONE IS ALONG THE LINE...05N77W TO 
06N85W TO 06N120W TO 07N140W. SCATTERED MODERATE WITH ISOLATED 
STRONG CONVECTION IS WITHIN THE AREA FROM 05N TO 07N FROM 83W TO 
90W. SCATTERED MODERATE CONVECTION IS WITHIN 60 NM OF THE POINT 
06.5N93.5W. SCATTERED MODERATE WITH ISOLATED STRONG CONVECTION 
IS WITHIN 90 NM EITHER SIDE OF THE ITCZ AXIS WEST OF 130W.

...DISCUSSION...

LARGE SCALE PATTERN IS IN PLACE. WEST OF ABOUT 120W A LARGE 
RIDGE COVERS THE AREA. MOST OF THIS AREA IS DRY AND CLOUD FREE 
IN THE MIDDLE AND UPPER LEVELS. THE EXCEPTION IS THE NORTHWEST 
PART NORTH OF 27N WEST OF 136W WHERE MULTIPLE LEVEL CLOUDS ARE 
PRESENT FROM A STRONG DEEP LAYER TROUGH WEST OF THE AREA. 

THE REMAINDER OF THE MIDDLE AND UPPER LEVELS NORTH OF THE ITCZ 
EAST OF 120W IS ANALYZED AS A LARGE TROUGH WITH AN AXIS FROM 
SOUTHERN TEXAS ACROSS MEXICO TO THE ITCZ NEAR 118W. A JETSTREAM 
RUNS FROM THE ITCZ NEAR 120W TO NEAR 20N100W TO THE NORTH PART 
OF THE YUCATAN PENINSULA. A PLUME OF UPPER LEVEL MOISTURE WITH 
BROKEN TO OVERCAST MIDDLE AND UPPER CLOUDS IS SOUTHEAST OF THIS 
JETSTREAM. MOST OF THE TROUGH NORTHWEST OF THE JETSTREAM IS DRY 
AND CLOUD FREE IN THE MIDDLE AND UPPER LEVELS. AN EXCEPTION IS 
WITHIN ABOUT 300 NM OF THE POINT 22.5N106W WHERE MULTIPLE LEVEL 
CLOUDS AND A FEW SHOWERS ARE LOCATED. ALSO SOME UPPER LEVEL 
MOISTURE AND SCATTERED HIGH CLOUDS ARE MOVING SOUTHEAST ACROSS 
NORTHERN BAJA CALIFORNIA.

AT THE SURFACE A MODERATE RIDGE IS NORTH OF 13N WEST OF 115W. A 
STATIONARY LOW PRESSURE IS CENTERED NEAR 07N119W. THE LOW IS 
FORECAST TO REMAIN NEARLY STATIONARY AND TO NOT DEVELOP. 
REMAINDER OF THE SURFACE IS ANALYZED AS A BROAD TROUGH CENTERED 
ON THE ITCZ.

GAP WINDS...GALE WARNING FOR GULF OF TEHUANTEPEC IS EXPECTED TO 
EXPIRE THIS AFTERNOON WITH N TO NE WINDS DIMINISHING TO 20 TO 25 
KT THEN CONTINUE THROUGH AT LEAST MONDAY.

THE COMBINATION OF STRONG TRADE WINDS IN THE CARIBBEAN AND LOCAL 
DRAINAGE EFFECTS WILL ALLOW THE FRESH WINDS TO PERSIST THROUGH 
THE GULF OF PAPAGAYO ALSO THROUGH AT LEAST MONDAY.

FOR ADDITIONAL INFORMATION PLEASE VISIT 
HTTP://WWW.HURRICANES.GOV/MARINE
  
$$
LL