000
AXPZ20 KNHC 222120
TWDEP 

TROPICAL WEATHER DISCUSSION      
NWS TPC/NATIONAL HURRICANE CENTER MIAMI FL
2205 UTC SUN JUL 22 2007

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.

...SPECIAL FEATURE...

TROPICAL DEPRESSION SEVEN-E CENTERED NEAR 12.9N 107.2W...OR 
ABOUT 415 NM SSE OF SOCORRO ISLAND...AT 2100 UTC MOVING W AT 7 
KT. MAXIMUM SUSTAINED WIND SPEED IS 30 KT WITH GUSTS TO 40 KT. 
ESTIMATED MINIMUM CENTRAL PRESSURE IS 1007 MB. VISIBLE SATELLITE 
IMAGERY SHOWS THAT THE LOW-LEVEL CENTER OF THE DEPRESSION IS 
PARTIALLY EXPOSED ON THE ERN EDGE OF THE DEEP CONVECTION...DUE 
TO FAIRLY STRONG 20-25 KT NORTHEASTERLY SHEAR OVER THE AREA. THE 
SYSTEM APPEARS AS THOUGH IT HAS TRIED TO DEVELOP A PERSISTENT 
CONVECTIVE BAND ON ITS WRN SIDE FOR MUCH OF THE DAY...BUT THE 
SHEAR HAS BEEN DESTROYING IT WITH NEW CONVECTION CONTINUOUSLY 
DEVELOPING CLOSER TO THE CENTER. NUMEROUS MODERATE/STRONG 
CONVECTION WITHIN 300 NM NW SEMICIRCLE. SCATTERED MODERATE ALSO 
E OF THE CENTER FROM 8N-15N BETWEEN 99W-109W. SEE LATEST NHC 
FORECAST/ADVISORY UNDER AWIPS/WMO HEADERS MIATCMEP2/WTPZ22 KNHC 
FOR MORE DETAILS. 

...ITCZ...

ITCZ AXIS IS CENTERED ALONG 6N77W 15N105W THEN 15N116W 9N130W 
8N140W. SCATTERED MODERATE CONVECTION WITHIN 90 NM S OF AXIS 
BETWEEN 79W-87W. SCATTERED MODERATE WITHIN 90 NM OF AXIS BETWEEN 
122W-131W. WIDELY SCATTERED MODERATE WITHIN 90 NM OF AXIS W OF 
134W.

...DISCUSSION...

E OF 110W...
AN ELONGATED UPPER LOW CENTERED NEAR THE YUCATAN PENINSULA AND A 
STRONG UPPER HIGH OVER NW MEXICO NEAR GUAYMAS CONTINUE TO 
PRODUCE A STEADY NORTHERLY FLOW ACROSS MUCH OF MEXICO EXTENDING 
S AND TURNING W OVER THE PACIFIC WATERS. THIS STRONG FLOW IS 
PRODUCING 20-25 KT OF NORTHEASTERLY SHEAR OVER T.D. 
SEVEN-E...AND ARRESTING ITS DEVELOPMENT FOR THE TIME BEING. 
TSTMS ARE FORMING OVER THE MEXICAN PLATEAU AND THE SRN MOUNTAINS 
AS THEY HAVE BEEN FOR THE PAST SEVERAL AFTERNOONS...AND SOME OF 
THESE TSTMS ARE EXPECTED TO REACH THE PACIFIC COAST DURING THE 
EVENING HOURS DUE TO THE NORTHERLY STEERING FLOW. FARTHER E...AN 
INVERTED UPPER TROUGH LIES S OF THE GULF OF TEHUANTEPEC ALONG 
96W AND WEAK DIFFLUENCE E OF THE AXIS IS AIDING IN THE 
PROPAGATION OF SCATTERED MODERATE CONVECTION OFF THE GUATEMALAN 
COAST N OF 11N BETWEEN 91W-94W. A CLOSED UPPER HIGH S OF JAMAICA 
IS ALSO PRODUCING BROAD AND DEEP EASTERLY FLOW OUT OF COLOMBIA 
INTO THE E PACIFIC BASIN...AND THE HIGH MOISTURE VALUES ARE 
ALLOWING SCATTERED TSTMS TO DEVELOP ALONG THE ITCZ AS WELL AS 
INLAND FROM PANAMA TO NICARAGUA.

W OF 110W...
THE PREVAILING UPPER LEVEL FEATURE OVER THE W PART OF THE AREA 
IS THE LARGE UPPER HIGH LOCATED OVER THE GULF OF CALIFORNIA NEAR 
26N110W WITH THE CIRCULATION COVERING PRACTICALLY THE ENTIRE 
AREA W OF 110W. THE HIGH IS ADVECTING DEEP TROPICAL MOISTURE 
FROM THE E PART OF THE BASIN WWD TO ABOUT 120W WHERE IT THINS 
OUT CONSIDERABLY IN FAVOR OF LARGE-SCALE SUBSIDENCE. A WEAK 
MID/UPPER TROUGH IS LOCATED ALONG 140W JUST W OF THE UPPER 
HIGH/RIDGE SYSTEM BUT IT IS NOT CAUSING ANY SIGNIFICANT WEATHER. 
THE SUBTROPICAL RIDGE AND THE EASTERLY TRADES REMAIN IN A 
SUBDUED STATE...AND THIS IS NOT EXPECTED TO CHANGE OVER THE NEXT 
FEW DAYS WITH A COLD FRONT/UPPER TROUGH APPROACHING THE NW PART 
OF THE REGION.
 
$$
BERG