000
AXPZ20 KNHC 190954
TWDEP 

TROPICAL WEATHER DISCUSSION
NWS TPC/NATIONAL HURRICANE CENTER MIAMI FL
1005 UTC MON MAY 19 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.

...TROPICAL WAVES...

A TROPICAL WAVE IS ANALYZED FROM 03N TO 12N ALONG 91W AND IS 
MOVING W AT AN ESTIMATED 12 KT. ALTHOUGH BROAD CYCLONIC TURNING 
IS NOTED IN THE AREA THERE IS SOME UNCERTAINTY ON THE TRUE WAVE 
POSITION. ALTHOUGH THERE IS A FEW CONVECTIVE CLUSTERS NEAR THE 
WAVE AXIS THERE ARE LARGER CLUSTERS WELL TO THE E AND TO THE W 
OF THE ESTIMATED WAVE POSITION. THUS FORECAST WAVE POSITIONS ARE 
NOTED DEPICTED ON THE MARINE GRAPHICS UNTIL MORE ACCURATE WAVE 
TRACKING RESUMES.

...ITCZ...

THE ITCZ AXIS IS ALONG LINE 04N77W TO 04N90W TO 09N110W 
TO 05N120W TO 03N140W. SCATTERED MODERATE ISOLATED STRONG 
CONVECTION IS NOTED TO THE N OF 03N E OF 81W AND ALSO WITHIN 150 
NM EITHER SIDE OF LINE FROM 14N97W TO 09N108W AND ALSO WITHIN 75 
NM EITHER SIDE OF LINE FROM 11N113W TO 09N118W TO 12N123W.

...DISCUSSION...

A STATIONARY UPPER LEVEL CYCLONE IS CENTERED AT 26N139W WITH ITS 
ENVELOPE OF CYCLONIC FLOW DOMINATING THE DISCUSSION AREA N OF 
14N W OF 131W. DRY UPPER AIR CIRCLES THE CYCLONE WITHIN ABOUT 
240 NM OF THE CENTER. AN UPPER LONGWAVE TROUGH CONTINUES TO 
DISSECT N AMERICA FROM NE TO SW WITH THE TROUGH ENTERING THE 
DISCUSSION AREA AT 31N93W AND CONTINUING SW TO AN UPPER CYCLONE 
AT 24N110W WHICH APPEARS TO BE CUTTING OFF. THE UPPER TROUGH 
CONTINUES S TO A BASE NEAR 16N113W. A LARGE AREA OF DRY UPPER 
AIR IS INDICATED OVER THE W SEMICIRCLE OF THE CYCLONE...ROUGHLY 
WITHIN 360 NM EITHER SIDE OF LINE FROM 16N110W TO BEYOND 32N122W.

AN UPPER ANTICYCLONE IS NEAR 14N95W WITH A RIDGE EXTENDING SW TO 
A CREST NEAR 10N130W. A NARROW UPPER RIDGE IS STILL EVIDENT 
ALONG POINTS 13N122W TO 25N126W AND STILL SEEMS TO SEPARATE THE 
FLOW ASSOCIATED WITH THE UPPER CYCLONES MENTIONED ABOVE.

UPPER DIFFLUENCE IS ENHANCING CONVECTION ALONG THE ITCZ W OF 
134W. THE RESULTANT DEBRIS MOISTURE SPREADS N OVER THE AREA 
BETWEEN 125W AND 131W. UPPER DIFFLUENCE IS ALSO ENHANCING 
CONVECTION ALONG THE ITCZ E OF 127W. THE UPPER DEBRIS MOISTURE 
IS ADVECTED NE ACROSS CENTRAL AMERICA BETWEEN 103W AND 
87W...WITH THE TROPICAL PLUME CONTINUING NE ACROSS THE SE GULF 
OF MEXICO AND MOST OF FLORIDA. DEBRIS MOISTURE OVER CENTRAL 
AMERICA E OF 87W APPEARS TO EVAPORATE IN DRY AIR ALOFT OVER THE 
W CARIBBEAN...HOWEVER THE WESTERN EXTENT OF THIS CARIBBEAN DRY 
AIR SEEMS TO SHIFTING E AWAY FROM CENTRAL AMERICA TONIGHT.

AT THE SURFACE...HIGH PRESSURE IS NEARLY STATIONARY NEAR 32N137W 
WITH A RIDGE EXTENDING SE TO NEAR 14N107W. THE LOW LEVEL 
EASTERLY TRADES SW OF THIS RIDGE ARE IN THE 20 KT RANGE BUT 
MODEL GUIDANCE NOW WEAKENS THE GRADIENT IN A COUPLE OF DAYS 
SUPPORTING ABOUT 15 KT. SOUTHERLY SWELL TO 8 FT HAS BEEN 
CROSSING THE EQUATOR OVER THE WATERS S OF 20N W OF 100W AND 
EXPECTED TO CONTINUE TO PROPAGATE N ACROSS MOST OF THE AREA S OF 
27N MIXING WITH THE NE WIND WAVES FROM THE NE TRADES...AND SOME 
REMNANT NW SWELL OVER THE W PORTION. NW SWELL ALONG THE NORTHERN 
BAJA PENINSULA WILL INCREASE TO 8 FT BY TUE WITH NW WINDS 
INCREASING TO 20 KT TUE NIGHT...AND FURTHER INCREASING TO 25 TO 
30 KT WED NIGHT WITH SEAS 10 TO 15 FT OVER WATERS N OF 28N E OF 
120W BY THU. 

$$
NELSON