000
AXPZ20 KNHC 032117
TWDEP 

TROPICAL WEATHER DISCUSSION    
NWS TPC/NATIONAL HURRICANE CENTER MIAMI FL
2205 UTC SAT JUL 03 2010

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 
2115 UTC.

...ITCZ...
AXIS ALONG 11N86W TO 12N91W TO 07N100W TO 11N115W TO 07N130W TO 
08N140W. SCATTERED MODERATE ISOLATED STRONG CONVECTION WAS 
WITHIN 90-120 NM OF AXIS W OF 128W...AND WITHIN 120-150 NM OF 
THE AXIS BETWEEN 95W AND 106W. 

...DISCUSSION...
COMPLEX BLOCKING UPPER PATTERN EXISTS TO THE N AND NW OF THE
DISCUSSION AREA WITH A QUASI STATIONARY UPPER LEVEL ANTICYCLONE 
NEAR 23N126W AND AN ASSOCIATED RIDGE EXTENDING ENE ACROSS SRN 
BAJA CALIFORNIA TO ANOTHER ANTICYCLONE OVER NRN MEXICO NEAR
27N105W. RIDGE ALSO EXTENDS SW TO A COL NEAR 17N143W. MID TO 
UPPER LEVEL CONVERGENCE YIELDING A VAST AREA OF DEEP LAYERED 
SUBSIDENCE PREVAILS TO THE NW OF THE RIDGE AXIS. THE ANTICYCLONE
OVER NRN MEXICO IS MAINTAINING AN AREA OF UPPER LEVEL DIVERGENT
FLOW THAT IS HELPING TO SUSTAIN DEEP CONVECTION ACROSS THE NE 
STATES OF MEXICO...ASSOCIATED WITH THE REMNANTS OF FORMER 
TROPICAL CYCLONE ALEX. MID TO UPPER LEVEL TROUGHING EXTENDS FROM 
THE N CENTRAL GULF OF MEXICO SSW ACROSS THE YUCATAN PENINSULA TO 
THE E PACIFIC NEAR 10N97W...JUST N OF THE ITCZ. NE TO E FLOW 
OCCURRING BETWEEN THIS TROUGHING AND THE UPPER RIDGE NOTED ABOVE 
IS CREATING A BROAD ZONE OF UPPER DIFFLUENCE N OF THE ITCZ W OF 
95W WITH UPPER LEVEL EASTERLY WINDS OF 55 TO 75 KT PER SATELLITE
DERIVED WINDS. THIS BROAD EASTERLY JET IS FORECAST TO SHIFT W OF 
125W DURING THE NEXT 24 HOURS. 

AT THE SURFACE...BROAD 1035 MB HIGH PRES WELL N OF THE 
DISCUSSION AREA NEAR 41N146W EXTENDS A RIDGE AXIS SE THROUGH 
30N133W TO 19N120W. STRONG NELY FLOW ALOFT ACROSS MEXICO S OF 
22N WILL LIMIT SUSTAINED DEEP CONVECTION THERE THROUGH THIS 
AFTERNOON BEFORE UPPER WINDS DIMINISH AND CONVECTIVE POTENTIAL 
IMPROVES OVERNIGHT INTO MONDAY. WITH THIS MONSOONAL REGIME IN 
PLACE...WEAK LOW LEVEL CYCLONIC CIRCULATIONS WERE NOTED ALONG 
THE ITCZ AT 105W AND 93W...WHERE ACTIVE CONVECTION WAS 
OCCURRING. LITTLE CHANGE IN THIS OVERALL PATTERN IS EXPECTED IN 
THE NEXT 24 HOURS.

A TIGHT GRADIENT BETWEEN THE BROAD SURFACE RIDGE AND 
CLIMATOLOGICAL TROUGHING ALONG THE SIERRA MADRES IS PRODUCING NW 
TO N WINDS OF NEAR 20 KT ALONG 30N AND E OF 125W. LOWER 
PRESSURES OVER THE SW CONUS HAS RESULTED IN A FETCH OF FUNNELED 
SE TO S WINDS OF 20 TO 25 KT WITHIN THE GULF OF CALIFORNIA N OF 
25N. FORECAST WINDS ARE EXPECTED TO DIMINISH ON BOTH SIDES OF 
BAJA CALIFORNIA WITHIN 24 TO 26 HOURS. 

A VERY LONG PERIOD...20-21 SECONDS...S-SW SWELL TRAIN 
ORIGINATING IN THE SRN HEMISPHERE IS MOVING NWD OVER AREAS N OF 
23N AND IS IMPACTING BAJA CALIFORNIA AND MEXICO. THIS SWELL IS 
IN THE PROCESS OF MERGING WITH ESTABLISHED NLY SWELLS N OF 23N
AND IS EXPECTED TO PRODUCE HIGH AND CONFUSED SEAS. THIS SWELL
WILL INCREASE OVER THE NEXT 12-24 HOURS AND MAY RESULT IN 
LARGE BREAKING WAVES AND DANGEROUS SURF CONDITIONS ALONG EXPOSED 
SHOALS...REEFS AND BEACHES. 

$$
COBB