000
AXPZ20 KNHC 290955
TWDEP 

TROPICAL WEATHER DISCUSSION 
NWS TPC/NATIONAL HURRICANE CENTER MIAMI FL
1005 UTC MON JAN 28 2008

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

BASED ON 0600 UTC SURFACE ANALYSIS AND SATELLITE IMAGERY THROUGH 
0945 UTC.
 
...ITCZ...
ITCZ AXIS IS CENTERED ALONG AXIS 2N78W 9N123W 5N140W. NO 
SIGNIFICANT CONVECTION. 

...DISCUSSION...
OMEGA BLOCK PATTERN SHIFTING E ACROSS THE CONUS WITH THE WESTERN 
UPPER LEVEL LONGWAVE TROUGH AXIS ALONG ABOUT 110W...WITH AN 
EMBEDDED SHORTWAVE TROUGH EXTENDING SW INTO THE DISCUSSION AREA 
ALONG 32N113W 24N127W. A BAND OF UPPER DRY AIR INDICATING 
SUBSIDENCE ACCOMPANIES THIS TROUGH WITHIN 120 NM EITHER SIDE OF 
LINE 32N113W 27N125W THEN THE SUBSIDENCE AREA WIDENS COVERING 
THE DISCUSSION AREA FROM 24N TO 32W BETWEEN 125W AND 145W. SOME 
UPPER MOISTURE IS SLIPPING SE TO THE THE N OF THIS DRY AIR...
SPREADING E ACROSS CALIFORNIA...GENERALLY COVERING THE UPPER 
LEVELS FROM 29N TO 32N BETWEEN 115W AND 125W.  

AN UPPER LEVEL ANTICYCLONE IS QUASI STATIONARY NEAR 13N110W WITH 
A RIDGE W TO 10N127W...AND A MORE IMPORTANT RIDGE EXTENDING NE 
ACROSS OLD MEXICO TO A SHARP MID LEVEL CREST OVER THE YUCATAN 
PENINSULA...HOWEVER THE UPPER RIDGE CONTINUES NE ACROSS THE 
OHIO VALLEY OF THE CONUS. A TROPICAL MOISTURE PLUME CONTINUES 
ALONG THE W PERIPHERY OF THE RIDGE AND JUST E OF THE UPPER
TROUGH...ROUGHLY WITHIN 480 NM EITHER SIDE OF LINE 10N150W 
18N123W...THEN THE PLUME NARROWS AS IT CONTINUES NE ACROSS 
NORTHERN OLD MEXICO ALONG 25N110W...THEN THE MOISTURE FANS OUT 
OVER THE TENNESSEE VALLY OF THE CONUS AS IT SLIPS UNDER THE 
UPPER RIDGE ALONG 21N120W TO WELL BEYOND 32N104W. SOME OF THE 
UPPER MOISTURE IS NOW SPILLING BACK SE OVER THE NE GULF OF 
MEXICO AND OVER FLORIDA TOWARDS THE NW BAHAMAS. 

THE EASTERN TROUGH OF THE OMEGA BLOCK HAS MOVED OFFSHORE THE 
CONUS WITH ITS MEAN AXIS ALONG 66W. THIS TROUGH HAS DEEPENED 
CONSIDERABLY AND NOW EXTENDS SW OVER THE CARIBBEAN TO A BASE 
NEAR PANAMA AND HAS PARTIALLY ERODED A RIDGE OVER COLOMBIA. 
HOWEVER THERE IS STILL SOME ANTICYCLONIC TURNING...INDICATING 
SLIGHT RIDGING REMAINS ALOFT OVER THE DEEP TROPICS S OF 8N 
BETWEEN 88W AND 78W. THE UPPER LEVELS ARE VERY DRY S OF 20N E OF 
107W...AND S OF 12N BETWEEN 107W AND 132W SUPPRESSING CONVECTION 
ALONG THE ITCZ.
 
AT THE SURFACE...A RIDGE EXTENDS ALONG 30N140W 15N105W. NE OF 
THE RIDGE NORTHERLY WINDS ARE IN THE 10 TO 15 KT RANGE BUT 
EXPECTED TO INCREASE TO 20 KT WED SPREADING E TO THE WESTERN 
COAST OF THE BAJA PENINSULA AND ALSO INCREASE TO 20 KT OVER THE 
SOUTHERN GULF OF CALIFORNIA WED...AND OVER THE NORTHERN GULF ON 
THU. NE TO E TRADES S OF THE RIDGE IN THE 20-25 KT RANGE WITH 
SEAS MAX ABOUT 13 FT NEAR 14N140W. OTHERWISE N AND NE SWELLS ARE 
NOTED W OF 110W WITH SOME SOUTHERLY SWELL CROSSING THE EQUATOR 
TO THE E OF 130W REACHING THE COAST OF CENTRAL AMERICA S OF 18N. 

GAP WINDS...GULF OF PAPAGAYO...NE 20 KT SURGES EXPECTED TO LAST 
THROUGH 48 HOURS. NORTHERLY WINDS 20 KT IN AND DOWNSTREAM OF THE 
GULF OF PANAMA THROUGH 48 HOURS BUT THE AFFECTED AREA IS 
EXPECTED TO GRADUALLY SHRINKING THEREAFTER. 

NELSON