000
AXPZ20 KNHC 301558
TWDEP 

TROPICAL WEATHER DISCUSSION  
NWS TPC/NATIONAL HURRICANE CENTER MIAMI FL
1605 UTC MON JUN 30 2008

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.

...SPECIAL FEATURES...

TROPICAL STORM BORIS IS CENTERED NEAR 14.8N 120.9W...OR ABOUT 795
NM...1470 KM...SOUTHWEST OF THE SOUTHERN TIP OF BAJA CALIFORNIA.
AT 30/1500 UTC MOVING W AT 11 KT. MAXIMUM SUSTAINED WIND SPEED 
HAS INCREASED TO 55 KT WITH GUSTS TO 65 KT. ESTIMATED MINIMUM 
CENTRAL PRESSURE IS 995 MB. SEE LATEST NHC FORECAST/ADVISORY 
UNDER AWIPS/WMO HEADERS MIATCMEP2/WTPZ22 KNHC FOR MORE DETAILS. 
BORIS HAS REMAINED STEADY STATE DURING THE PAST 6 TO 12 HOURS...
WITH ITS MAIN DEFINING FEATURE A LARGE AMORPHOUS CLUSTER OF 
CONVECTION NEAR BUT S OF THE CENTER. A PROMINENT BAND TO THE S 
AND SW ALSO RISES ENE AND NE TOWARD THE STORM CIRCULATION BUT 
APPEARS PARTLY DETACHED FROM THE CORE OF BORIS. CIMSS SHEAR 
ANALYSES STILL INDICATE MODERATE SHEAR OVER THE TROPICAL CYCLONE 
FROM THE ENE TO NE...BUT THE SHEAR HAS NOT PROVEN ENOUGH TO 
RESULT IN WEAKENING.  NUMEROUS STRONG CONVECTION LIES WITHIN 180 
NM IN THE S SEMICIRCLE...WHILE LITTLE TO NO CONVECTION IS 
APPARENT TO THE N. SCATTERED MODERATE SCATTERED STRONG 
CONVECTION IS ALSO NOTED TO THE S IN THE STRONG BAND...WITHIN 90 
NM EITHER SIDE OF FROM 09N125W TO 12N118W.

TROPICAL DEPRESSION CRISTINA IS CENTERED NEAR 14.3N 131.2W...OR 
ABOUT 1315 NM...2435 KM...WSW OF THE SOUTHERN TIP OF THE BAJA 
PENINSULA...AT 30/1500 UTC MOVING W AT 10 KT. MAXIMUM SUSTAINED 
WIND SPEEDS ARE 30 KT WITH GUSTS TO 40 KT. ESTIMATED MINIMUM 
PRESSURE IS 1005 MB. SEE LATEST NHC FORECAST/ADVISORY UNDER 
AWIPS/WMO HEADERS MIATCMEP3/WTPZ23 KNHC FOR MORE DETAILS. 
SATELLITE PICTURES INDICATE THAT STRONG E TO ENE SHEAR OF AROUND 
20 KT HAS STRIPPED ALL DEEP CLOUDS AWAY FROM THE CENTER OF 
CRISTINA DURING THE PAST 6 HOURS. THE NEAREST CONVECTION...MORE 
THAN 90 NM REMOVED FROM THE CENTER... DISSIPATED JUST PRIOR TO 
1200 UTC. FIRST VISIBLE IMAGES NOW CONFIRM THE EFFECTS OF THE 
SHEAR BY SHOWING A SWIRL OF LOW CLOUDS MOVING ALONG WITH THE 
LOW-LEVEL FLOW. CRISTINA SHOULD CONTINUE TO WIND DOWN THANKS TO 
NO RELIEF IN VERTICAL SHEAR AND SUB-80 F WATER TEMPERATURES.

A 1008 MB LOW HAS BEEN RELOCATED NEAR 12N102.5W MOVING WNW ABOUT 
10 KT. MORNING VISIBLE PICTURES REVEAL THE BEGINNINGS OF A 
BANDING FEATURE ARCING FROM SW TO NE AROUND THE NASCENT 
CIRCULATION CENTER...WHICH APPEARS TO BE ELONGATED ALONG AN AXIS 
EXTENDING SEVERAL HUNDRED MILES TO THE E. HOWEVER...THE 
CONVECTIVE ELEMENTS WITHIN THE PRIMITIVE BAND ARE NOT CONTINUOUS 
AND ARE MORE THAN A DEGREE REMOVED FROM THE POORLY-DEFINED 
CENTER. OVERALL THE SYSTEM HAS CHANGED LITTLE SINCE YESTERDAY 
...THOUGH THERE IS SOME EVIDENCE THAT THE VIGOR OF THE LOW-LEVEL 
CIRCULATION HAS INCREASED SOME. THERE CONTINUES TO BE POTENTIAL 
FOR THIS SYSTEM TO DEVELOP INTO A TROPICAL CYCLONE DURING THE 
NEXT 24 TO 48 HOURS. SCATTERED MODERATE ISOLATED STRONG 
CONVECTION IS OBSERVED WITHIN 90 NM EITHER SIDE OF LINE RUNNING 
FROM 11N108W TO 14N102W TO 10N94W.

...ITCZ...

ITCZ AXIS IS CENTERED ALONG 10N85W TO 12N102W TO 10N110W TO 
12N120W TO 10N130W TO 06N140W. ISOLATED MODERATE CONVECTION IS 
WITHIN 150 NM EITHER SIDE OF AXIS FROM 88W TO 98W. NUMEROUS 
MODERATE SCATTERED STRONG CONVECTION IS WITHIN 240 NM N OF AXIS 
BETWEEN 99W AND 108W. SCATTERED MODERATE IS WITHIN 300 NM S OF 
AXIS BETWEEN 108W AND 114W. NUMEROUS MODERATE SCATTERED STRONG 
CONVECTION 90 NM EITHER SIDE OF AXIS BETWEEN 118W AND 128W. 
SCATTERED MODERATE IS WITHIN 60 NM EITHER SIDE OF AXIS BETWEEN 
134W AND 138W.

...DISCUSSION...

ENHANCED SUBTROPICAL RIDGE OVER THE EAST PACIFIC SHOULD REMAIN 
IN PLACE DURING THE NEXT 24 TO 48 HOURS ...WHICH SHOULD HELP 
ACCENTUATE THE TYPICAL PRESSURE GRADIENT OFFSHORE THE BAJA 
CALIFORNIA PENINSULA. AS THIS OCCURS...EXPECT NW WINDS OF 20 TO 
PERHAPS 25 KT TO DEVELOP INITIALLY N OF 27N E OF 118W AND THEN 
EXPAND SOUTH AND WEST BY TUE. IN RESPONSE...SEAS OF UP TO 8 TO 9 
FT IN NEWLY-FORMED WIND WAVES AND SW SWELL ARE POSSIBLE WITHIN 
180 NM W OF THE W COAST OF THE BAJA PENINSULA N OF 27N THROUGH 
MID- WEEK.

AN UNUSUALLY AMPLIFIED MID- TO UPPER-LEVEL TROUGH DIGGING ALONG 
140W SHOULD DRIVE A COLD FRONT THROUGH HAWAII TUE AFTERNOON... 
WITH THE NE PORTION OF THE FRONT ENTERING THE FAR NW WATERS OF 
THE EAST PACIFIC BY EARLY WED.  AHEAD OF THE FRONT MODEL 
GUIDANCE IS INDICATING S TO SW WINDS UP TO 20 KT INITIALLY NW OF 
A LINE FROM 29N140W TO 30N138W AND THEN EXPANDING FAR S AND E 
DURING THE NEXT 24 TO 36 HOURS. EXPECT SEAS OF UP TO 9 FT IN 
LONG PERIOD NW SWELL PROPAGATING OUT OF THE CENTRAL NORTH 
PACIFIC.

ELSEWHERE...SURROUNDING BORIS...STRONG CROSS-EQUATORIAL FLOW 
FLOWING NORTHWARD INTO THE BROAD SURFACE LOW NEAR 12N102.5W IS 
AGITATING SEAS FROM 3N TO 10N BETWEEN 95W AND 108W.  IN FACT...A 
1306 UTC QUIKSCAT PASS SHOWED S TO SW WINDS OF UP TO 20 KT OVER 
THIS AREA...AND THE NOAA WAVEWATCH III MODEL INDICATES THE 
POTENTIAL FOR UP TO 8 FT.  

FINALLY...FRESH TRADES W AND NW OF CRISTINA ARE AFFECTING SEAS 
FROM 10N TO 20N W OF 131W.  RECENT QUIKSCAT PASSES AND MODEL 
GUIDANCE INDICATE NE WINDS OF UP TO 20 KT AND SEAS ARE LIKELY AS 
HIGH AS 8 OR 9 FT IN NE SWELL.

$$
KIMBERLAIN