000
AXPZ20 KNHC 270311
TWDEP 

TROPICAL WEATHER DISCUSSION      
NWS TPC/NATIONAL HURRICANE CENTER MIAMI FL
0405 UTC FRI JUL 27 2007

TROPICAL WEATHER DISCUSSION FOR THE EASTERN PACIFIC OCEAN
FROM THE EQUATOR TO 32N...EAST OF 140W. 

BASED ON 0000 UTC SURFACE ANALYSIS AND SATELLITE IMAGERY THROUGH 
0330 UTC.

...SPECIAL FEATURE...
TROPICAL STORM DALILA AT 22.6N 116.3W AT 27/0300 UTC MOVING W NW 
AT 10 KT. MAXIMUM SUSTAINED WIND SPEED 35 GUSTS TO 45 KT. 
ESTIMATED MINIMUM CENTRAL PRESSURE 1003 MB. DEEP CONVECTION 
ASSOCIATED WITH DALILA HAS DIMINISHED TONIGHT AS IT MOVES OVER 
COOLER SEA SURFACE TEMPERATURE OF 24C. IT COULD BECOME A REMNANT 
LOW AS EARLY AS TOMORROW EVENING. SCATTERED MODERATE CONVECTION 
FROM 22N TO 24N BETWEEN 114W AND 117W. SEE LATEST NHC FORECAST/ 
ADVISORY UNDER AWIPS/WMO HEADERS MIATCMEP2/WTPZ22 KNHC FOR MORE 
DETAILS.

...TROPICAL WAVES...
TROPICAL WAVE IS ADJUSTED AHEAD NEAR 101W N OF 4N. NIGHT CHANNEL 
SAT IMAGERY SHOWS SOME TURNING ALONG THE WAVE AXIS NEAR 10N. 
SCATTERED MODERATE CONVECTION FROM 7N TO 14N BETWEEN 98W AND 
106W. COMPUTER MODEL SUGGESTS THAT A WEAK LOW WILL FORM ALONG 
THE WAVE AXIS DURING THE NEXT 24 HOURS OR SO. 

...ITCZ...
ITCZ AXIS ALONG 6N78W 12N97W 6N107W 17N111W 12N140W. NO DEEP 
CONVECTION IS ASSOCIATED WITH THE ITCZ WITH THE EXCEPTION OF 
SCATTERED MODERATE CONVECTION FROM 7N TO 14N BETWEEN 98W AND 106 
RELATED TO A TROPICAL WAVE. 

...DISCUSSION...
AN ELONGATED UPPER RIDGE AXIS FROM 32N120W TO 11N140W IS 
BLOCKING THE MOVEMENT OF STRONG UPPER LEVEL TROUGH DRAGGING SW 
FROM A CYCLONIC VORTEX AT 30N140W. THIS RIDGE IS PRODUCING 
ABUNDANT DRY STABLE AIR ALOFT W OF 120W. THIS STABLE AIRMASS IS 
LIMITING ANY DEEP CLOUD FORMATION...EVEN ALONG THE ITCZ. 
INCREASING SWLY FLOW AHEAD OF THE AFOREMENTIONED UPPER TROUGH IS 
BRINGING SOME UPPER LEVEL MOISTURE INTO THE AREA N OF 15N W OF 
135W.  

LARGE ANTICYCLONE REMAINS OVER THE YUCATAN PENINSULA PRODUCING 
AN EXTENSIVE ELY UPPER FLOW OVER CENTRAL AMERICA AND THE EPAC 
E OF 110W. THESE WINDS ARE ADVECTING DEEP MOISTURE THROUGH 
CENTRAL AMERICA INTO THE PACIFIC OCEAN. UPPER DIFFLUENCE BETWEEN 
A TROUGH OVER COAHUILA IN MEXICO AND RIDGING OVER THE SW U.S. IS 
HELPING TO GENERATE SCATTERED MODERATE CONVECTION ALONG THE 
SIERRA MADRE OCCIDENTAL OF MEXICO.  

AT THE SURFACE...
DALILA REMAINS THE MAIN WEATHER FEATURE ACROSS THE BASIN.  
BROKEN TO OVERCAST STRATOCUMULUS CLOUDS COVER THE AREA N OF 15N 
WEST OF 120W UNDER THE INFLUENCE OF A SURFACE RIDGE ANCHORED ON 
A HIGH LOCATED N OF AREA. THIS RIDGE IS PRODUCING LIGHT TO 
MODERATE TRADE WINDS.

$$
GR