000
AXPZ20 KNHC 152133
TWDEP 

TROPICAL WEATHER DISCUSSION
NWS TPC/NATIONAL HURRICANE CENTER MIAMI FL
2205 UTC TUE APR 15 2008

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 
2100 UTC.

...ITCZ...

ITCZ AXIS IS CENTERED ALONG 02N78W 01N90W 07N110W 04N140W. 
SCATTERED MODERATE/ISOLATED STRONG CONVECTION FROM 07N-15N 
BETWEEN 95W-110W. SCATTERED MODERATE FROM 06N-10N BETWEEN 
114W-124W. SCATTERED MODERATE/STRONG WITHIN 90 NM OF AXIS W OF 
128W.

...DISCUSSION...

W OF 115W...
A CUT-OFF UPPER LOW IS LOCATED JUST W OF THE AREA NEAR 25N141W 
WITH A TROUGH AXIS EXTENDING SWD ALONG 141W TO NEAR 5N...WITH 
BROAD SOUTHWESTERLY FLOW LYING TO THE E TO NEAR 115W. THE UPPER 
LOW IS ATTACHED TO ANOTHER TROUGH AXIS WHICH EXTENDS TO SOUTHERN 
CALIFORNIA...BUT THE BULK OF THE TROUGHING LIES WELL TO THE N 
ACROSS THE WESTERN UNITED STATES. FARTHER S...A SHORTWAVE TROUGH 
IS EMBEDDED WITHIN THE LARGER-SCALE TROUGH FROM 14N126W TO 
2N115W AND UPPER DIFFLUENCE IS ENHANCING CONVECTION ALONG THE 
ITCZ W OF 128W. IN THE LOW-LEVELS...THE SUBTROPICAL RIDGE IS IN 
PLACE FROM 30N134W TO 21N115W WITH MODERATE 20-25 KT TRADES 
LYING SW OF THE AXIS...AND LARGE 8-13 FT SWELLS MOVING INTO THE 
NW PART OF THE REGION. A BROKEN STRATOCUMULUS FIELD LIES N OF 
14N W OF 122W WHILE SKIES ARE CLEARING NEAR THE BAJA CALIFORNIA 
COAST.

E OF 115W...
LARGE-SCALE RIDGING IS IN PLACE OFF THE SW COAST OF MEXICO WITH 
A MEAN AXIS STRETCHING FROM NW COLOMBIA TO NEAR 13N115W. A 
SHORTWAVE TROUGH...AS MENTIONED ABOVE...LIES WITHIN THE TROPICS 
JUST W OF 115W BUT IS PRODUCING DOWNSTREAM UPPER 
DIFFLUENCE...RESULTING IN WIDESPREAD CONVECTIVE ACTIVITY FROM 
6N-15N BETWEEN 95W-115W. DRIER WEATHER IS LOCATED E OF 95W DUE 
TO AN UPPER HIGH CENTERED OVER NICARAGUA AND COSTA RICA...AND AN 
ASSOCIATED PATCH OF MODERATE/STRONG SUBSIDENCE OVER SRN CENTRAL 
AMERICA. FARTHER N...A PROGRESSIVE UPPER LEVEL SHORTWAVE RIDGE 
IS LOCATED ALONG 110W MOVING ACROSS THE BAJA PENINSULA AND NW 
MEXICO...TRANSITIONING INTO A DEEP-LAYERED TROUGH OVER THE GULF 
OF MEXICO. MODERATE/STRONG SUBSIDENCE IS ASSOCIATED WITH THE 
RIDGE AXIS AND IS SPREADING ACROSS NORTHERN MEXICO ALTHOUGH 
THERE IS STILL ENOUGH LOW-LEVEL INSTABILITY FOR CONVECTIVE 
SHOWERS TO DEVELOP OVER THE MEXICAN PLATEAU.

GALE CONDITIONS ARE OCCURRING OVER THE GULF OF TEHUANTEPEC DUE 
TO HIGH PRES CENTERED OVER THE LOWER MISSISSIPPI VALLEY...WITH 
WINDS CURRENTLY AS HIGH AS 40 KT. THE HIGH IS EXPECTED TO SHIFT 
SLOWLY E OVER THE NEXT DAY AND WINDS WILL DROP BELOW GALE FORCE 
BY WED MORNING...THEN BELOW 20 KT BY THU AFTERNOON. WINDS ARE 
CURRENTLY 20-25 KT OVER THE GULF OF PAPAGAYO AND SHOULD ONLY 
SLOWLY DIMINISH OVER THE NEXT 48 HRS.

$$
BERG