000
AXPZ20 KNHC 201516
TWDEP 

TROPICAL WEATHER DISCUSSION  
NWS NATIONAL HURRICANE CENTER MIAMI FL
1605 UTC THU JAN 20 2011

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...
AXIS IS ALONG 7N77W 5N100W 8N135W 7N140W. SCATTERED MODERATE 
ISOLATED STRONG CONVECTION WITHIN 120 NM S OF AXIS FROM 78W-81W 
AND FROM 2N-4N BETWEEN 85W-88W.

...DISCUSSION...
AN UPPER LEVEL TROUGH EXTENDING FROM THE SOUTHWESTERN U.S. 
THROUGH CENTRAL BAJA CALIFORNIA TO 27N135W THEN NW TO 32N140W. 
MODERATE TO STRONG SUBSIDENCE WITH DRY STABLE AIR IS N OF THE 
TROUGH AND S OF THE TROUGH TO 20N. AN 80-100 KT JET STREAM 
EXTENDS FROM THE SOUTHERN TIP OF THE BAJA PENINSULA ACROSS 
NORTHERN MEXICO. A BROAD UPPER LEVEL RIDGE EXTENDS FROM AN 
ANTICYCLONIC CIRCULATION OFF THE COAST OF COSTA RICA NEAR 9N86W 
ACROSS CENTRAL AMERICA INTO THE GULF OF MEXICO.

IN THE DEEP TROPICS AN UPPER LEVEL TROUGH EXTENDS FROM 15N115W 
TO EQUATOR AT 100W. A 70-80 KT JET STREAM OVER THE SE PORTION OF 
THE DISCUSSION AREA IS S OF 7N W OF 100W. SOME HIGH LEVEL 
MOISTURE IS ALONG THE JET. MODERATE TO STRONG SUBSIDENCE IS S OF 
15N BETWEEN 95W AND 110W.

A STRONG SURFACE HIGH PRES IS LOCATED WELL TO THE N OF THE AREA 
WITH A RIDGE EXTENDING SEWD TO 32N135W TO 22N122W. A TIGHT PRES 
GRADIENT ON THE SOUTHERN PERIPHERY OF THE RIDGE IS PRODUCING NE 
TO E WINDS 20-25 KT N OF 25N W OF 123W. THE RIDGE WILL WEAKEN 
AND THE WINDS ARE EXPECTED TO DECREASE ON FRI. LARGE NW SWELL 
WITH SEAS UP TO 15 FT WILL MOVE INTO THE FAR NW PORTION OF THE 
AREA FRI AFTERNOON AND SPREADING SE SAT.

A COUPLE OF SURFACE TROUGHS ARE ANALYZED ALONG THE ITCZ. THE 
FIRST IS FROM 3N-9N ALONG 88W. SCATTERED MODERATE ISOLATED 
STRONG CONVECTION IS WITHIN 90 NM EITHER SIDE OF TROUGH S OF 4N. 
ANOTHER TROUGH EXTENDS FROM 13N133W TO 5N134W. A FEW SHOWERS ARE 
ALONG THE TROUGH.

$$
DGS