000
AXPZ20 KNHC 290939
TWDEP 

TROPICAL WEATHER DISCUSSION
NWS TPC/NATIONAL HURRICANE CENTER MIAMI FL
1005 UTC THU MAY 29 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 
0915 UTC.

...SPECIAL FEATURE...

TROPICAL DEPRESSION ONE-E IS CENTERED AT 10.9N 86.8W AT 0900 UTC 
AND IS MOVING JUST W OF DUE N AT 4 KT. ESTIMATED MINIMUM CENTRAL 
PRESSURE IS 1003 MB. MAXIMUM SUSTAINED WINDS HAVE INCREASED TO 
30 KT WITH GUSTS TO 40 KT. SEE LATEST NHC FORECAST/ADVISORY 
UNDER AWIPS/WMO HEADERS MIATCMEP1/WTPZ21 KNHC FOR FURTHER 
DETAILS. THE DEPRESSION HAS GRADUALLY BEEN ORGANIZING DURING THE 
PAST SIX HOURS...WITH RECENT SATELLITE IMAGERY INDICATING NOT 
ONLY A PRIMITIVE AND PERSISTENT BANDING FEATURE COVERING MOST OF 
THE WESTERN SEMICIRCLE BUT ALSO A RECENT BURST OF CONVECTION 
NEAR AND SE OF THE CENTER. ANOTHER BAND LOCATED 150-200 NM SE OF 
THE CENTER EARLIER IN THE NIGHT APPEARS TO BE DISSIPATING 
...POSSIBLY AT THE EXPENSE OF A LARGER CONVECTIVE BLOW-UP 
LOCATED BETWEEN 60-210 NM W OF THE CENTER.  THIS FEATURE...A 
CONSEQUENCE OF THE STORM CIRCULATION AND LATE AFTERNOON 
CONVECTION FROM YESTERDAY MEETING THE LARGER-SCALE MONSOONAL 
FLOW TO THE WEST...HAS TAKEN ON A LIFE OF ITS OWN...WITH A BROAD 
AREA OF GREATER THAN -80C CONVECTIVE TOPS NOTED WITHIN THE LAST 
FEW HOURS.  OTHERWISE...AN EARLIER ASCAT PASS REVEALED S TO SW 
20 TO 30 KT WINDS IN THE PERIPHERAL BUT DECAYING BAND TO THE 
SE.  THE SAME PASS ALSO WAS USEFUL IN IDENTIFYING THE LIKELY 
CENTER...WITH SEVERAL 25 TO 30 KT WIND BARBS NEAR AND N OF THE 
CIRCULATION. LATEST GUIDANCE SUGGESTS THAT THE DEPRESSION SHOULD 
TRACK MORE TO THE LEFT WITH SOME INCREASE IN FORWARD SPEED LATER 
TODAY...WITH THE SYSTEM LIKELY REACHING TROPICAL STORM STRENGTH 
AS IT NEARS THE EL SALVADOR/HONDURAN COASTS LATE TONIGHT.  THE 
FORECAST CALLS FOR A MINIMAL TROPICAL STORM TO MOVE INLAND OVER 
NEAR THE GULF OF FONSECA EARLY SAT...WITH THE PRIMARY THREAT 
LIKELY TO BE HEAVY RAINS OVER MUCH OF CENTRAL 
AMERICA...ESPECIALLY NEAR HIGHER TERRAIN.

...TROPICAL WAVES...

A TROPICAL WAVE OF WEAK AMPLITUDE ALONG 84W CONTINUES MOVING W 
AT 10-15 KT...ALONG THE NE PERIPHERY OF TROPICAL DEPRESSION 
ONE-E. CONVECTION REMAINS ENHANCED ALONG THE CARIBBEAN COAST OF 
NICARAGUA...LIKELY IN ASSOCIATION WITH THIS FEATURE.

...ITCZ...
FROM 10N87W TO 04N94W TO 04N110W TO 05N130W TO 09N140W. 
SCATTERED MODERATE CONVECTION IS NOTED WITHIN 60 NM EITHER SIDE 
OF AXIS BETWEEN 90W AND 96W. ISOLATED MODERATE WITHIN 90 NM 
EITHER SIDE OF AXIS BETWEEN 111W AND 120W. SCATTERED MODERATE 
ISOLATED STRONG WITHIN 30 NM OF LINE FROM 14N94W TO 13N96W.

...DISCUSSION...

WATER VAPOR IMAGERY AND CLOUD-TRACKED WINDS INDICATE A BROAD 
MID- TO UPPER-LEVEL TROUGH EXTENDING FROM OFFSHORE THE U.S. WEST 
COAST THROUGH THE WATERS W OF 120W...WITH AN AXIS ALONG 30N124W 
TO 20N130W TO 17N140W.  WEAK HIGH PRESSURE IN THE WAKE OF THE 
TROUGH AND RELATIVE LOW PRESSURE OVER THE DESERT SW IS INDUCING 
AN INCREASING N TO NW FLOW OVER THE WATERS N OF 25N WITHIN 180 
NM W OF THE BAJA CALIFORNIA COAST. IN FACT...A LATE EVENING 
QUIKSCAT PASS FROM YESTERDAY SHOWED WIDESPREAD NW 20 KT WINDS 
GENERALLY N OF 25N E OF 118W. NOAA WAVEWATCH GUIDANCE SUGGESTS 
SEAS RANGE FROM 5 TO 8 FT ACROSS THIS AREA IN A MIX OF NW SWELL 
LONG PERIOD NW SWELL COMING OUT OF THE NORTH PACIFIC...
N WIND WAVES...AND WEAKER SOUTH SWELL WITH ORIGINS FROM THE 
SOUTHERN HEMISPHERE.  OVER THE NEXT 24 TO 36 HOURS...THE TROUGH 
NOW NEAR THE WEST COAST SHOULD RIDE OVER A HUGE HEAT RIDGE 
ALREADY FORMING FROM NORTHERN MEXICO THROUGH FLORIDA.  THIS 
SHOULD CAUSE THE BRISK NLY FLOW NEAR AND OFFSHORE THE BAJA 
PENINSULA TO BRIEFLY DIMINISH FRI AFTERNOON THROUGH EARLY SAT.  
HOWEVER...A PIECE OF SHORTWAVE ENERGY FROM A STRENGTHENING 
PACIFIC JET SHOULD REINFORCE THE LONGWAVE TROUGH OVER THE FAR 
WEST LATER SAT AND SUN. THIS SHOULD CAUSE JUST AS STRONG OF A 
NLY FLOW TO RETURN LATE THIS WEEKEND...WITH SEAS POSSIBLY 
BUILDING UP TO 10 FT W OF BAJA CALIFORNIA BY MON.

ELSEWHERE...THE DIFFERENCE BETWEEN DEEP LOW PRESSURE ASSOCIATED 
WITH TROPICAL DEPRESSION ONE-E AND RELATIVE HIGH PRESSURE OVER 
THE GULF OF MEXICO HAS LED TO A RARE LATE MAY GAP WIND EVENT 
OVER THE GULF OF TEHUANTEPEC.  ALREADY N WINDS OF 20 TO 30 KT 
HAVE BECOME ESTABLISHED DOWNWIND OF THE GULF OF TEHUANTEPEC 
...CAUSING SEAS TO BUILD TO 5 TO 7 FT IN N WIND WAVES.  THE 
LENGTH OF THIS EVENT DEPENDS VERY MUCH ON THE FUTURE TRACK OF 
THE TROPICAL DEPRESSION.  IF...AS FORECAST...TROPICAL DEPRESSION 
REACHES THE CENTRAL AMERICAN COAST BY EARLY SAT...EXPECT WINDS 
TO PEAK TODAY ROUGHLY 60 NM EITHER SIDE OF A LINE EXTENDING FROM 
16N94.5W TO 12N94.5W AND SEAS TO BUILD TO 8 TO 10 FT IN STEEP N 
WIND WAVES. THEREAFTER...WINDS SHOULD QUICKLY ABATE AND SEAS 
SHOULD GRADUALLY DIMINISH GOING INTO SAT.

$$

KIMBERLAIN