000
AXPZ20 KNHC 030417
TWDEP 

TROPICAL WEATHER DISCUSSION
NWS NATIONAL HURRICANE CENTER MIAMI FL
0405 UTC MON SEP 03 2012

TROPICAL WEATHER DISCUSSION FOR THE EASTERN PACIFIC OCEAN FROM 
THE EQUATOR TO 32N...EAST OF 140W. THE FOLLOWING INFORMATION IS 
BASED ON SATELLITE IMAGERY...WEATHER OBSERVATIONS...RADAR...AND 
METEOROLOGICAL ANALYSIS.

BASED ON 0000 UTC SURFACE ANALYSIS AND SATELLITE IMAGERY THROUGH 
0315 UTC.

...SPECIAL FEATURE...

TD TEN-E IS AT 19.0N 110.9W 1001 MB AT 0300 UTC...MOVING WNW OR 
300 DEG AT 15 KT ALONG THE SOUTHERN PERIPHERY OF A MID TO UPPER 
LEVEL RIDGE. CURRENTLY SCATTERED MODERATE TO STRONG CONVECTION 
IS OBSERVED WITHIN 180 NM ONLY OVER THE W SEMICIRCLE. MAXIMUM 
SUSTAINED WINDS ARE 30 KT WITH GUSTS TO 40 KT MAINLY WELL E OF 
THE CENTER. ALTHOUGH THE SYSTEM IS EXPERIENCING NORTHEASTERLY 
WIND SHEAR CONTINUED SLOW DEVELOPMENT IS EXPECTED...AND MINIMAL 
TROPICAL STORM FORCE WINDS ARE FORECAST WITHIN 12 HOURS WITH 
WINDS MAINLY OVER THE N SEMICIRCLE AND SE QUADRANT. THE SYSTEM 
WILL TRACK OVER COOLER SURFACE WATERS LATE MON AND MON NIGHT AND 
WEAKEN BELOW TROPICAL STORM FORCE EARLY TUE. SEE THE LATEST NHC 
FORECAST/ADVISORY UNDER AWIPS/WMO HEADERS MIATCMEP5/WTPZ25 KNHC 
FOR MORE DETAILS. 

...INTERTROPICAL CONVERGENCE ZONE/MONSOON TROUGH...

THE MONSOON TROUGH EXTENDS W TO E ALONG 09N FROM THE 
PANAMA/COLOMBIA BORDER TO ACROSS PANAMA TO THE SOUTHERN COAST OF 
COSTA RICA...TO THE PACIFIC AT 08N91W...THEN NW TO 12N100W 
WHERE IT LOSES IDENTITY IN THE BROAD CYCLONIC CIRCULATION 
ASSOCIATED WITH DEVELOPING TD TEN-E. THE MONSOON TROUGH BECOMES 
DEFINED AGAIN SW OF THE TD 10-E NEAR 15N112W...AND EXTENDS SW TO 
08N131W...THEN WESTWARD TO BEYOND 09N140W. 

SCATTERED MODERATE ISOLATED STRONG CONVECTION IS OBSERVED ALONG 
THE EASTERN SEGMENT OF THE MONSOON TROUGH...FROM 04N TO 12N E OF 
97W WITH THE STRONGEST ACTIVITY DETECTED BY LIGHTNING DATA ALONG 
THE COLOMBIA COAST...AND ALSO IN A CLUSTER MOVING OFFSHORE THE 
PACIFIC COAST OF COSTA RICA. A LARGE AREA OF MODERATE 
CONVECTION WITH A FEW EMBEDDED STRONG CELLS IS OBSERVED TO THE S 
OF TD-10E FROM 08N TO 17N BETWEEN 104W AND 113W. SCATTERED 
MODERATE CONVECTION IS DISSIPATING WITHIN 60 NM OF 07N105W.

SCATTERED MODERATE CONVECTION IS OBSERVED WITHIN 30 NM W OF BAJA 
CALIFORNIA PENINSULA FROM BAHIA SANTA MARIA AT 24.5N NORTHWARD 
ACROSS ASUNCION BAY TO BAHIA SAN HIPOLITO NEAR 27N. SCATTERED 
MODERATE ISOLATED STRONG CONVECTION IS NOTED WITHIN 30 NM OF 
MEXICAN COAST FROM CAPE CORRIENTES AT 20N TO LA PAZ AT 24.5N.
SMALL THUNDERSTORM CLUSTERS ARE ALSO MOVING OFF THE MEXICAN 
COAST AT 15N AND 16.5N.

...DISCUSSION...

A UPPER SHORTWAVE TROUGH EXTENDS SW INTO THE DISCUSSION AREA 
FROM 32N126W TO 23N132W. IMMEDIATELY TO THE SW AN UPPER LEVEL 
ANTICYCLONE HAS SHIFTED WESTWARD TO 22.5N142W BUT ITS RIDGE 
STILL EXTENDS E TO A SHARP CREST OVER THE DISCUSSION AREA AT 
21N133W. THE NE PORTION OF THE DISCUSSION AREA IS DOMINATED BY 
AN UPPER ANTICYCLONE CENTERED OVER OLD MEXICO/TEXAS BORDER NEAR 
29N102W...WITH AN UPPER RIDGE EXTENDING W ACROSS OLD MEXICO 
ALONG 28N TO A CREST OVER THE PACIFIC AT 27.5N126W. THE 
ANTICYCLONIC FLOW ALONG THE SOUTHERN PERIPHERY OF THIS RIDGE IS 
STEERING TD TEN-E WESTWARD...BUT TURNS ABRUPTLY CYCLONIC INTO AN 
SMALL UPPER TROUGH DIRECTLY OVER THE REMNANT LOW 1008 MB PRES OF 
TROPICAL CYCLONE ILEANA AT 22.5N124.5W.

A TROPICAL UPPER CYCLONE IS AT 12N128W AND IS ACCOMPANIED BY 
VERY DRY UPPER AIR WITH CONVECTION SUPPRESSED ALONG THE MONSOON 
TROUGH TO THE W OF 115W. A SMALL UPPER CYCLONE IS AT 11N118W 
WITH AN ILL-DEFINED UPPER TROUGH EXTENDING SE TO NEAR 06N118W.   
A LARGE AREA OF UPPER DIFFLUENCE EXISTS S OF THE MEXICAN RIDGE 
IN THE AREA FROM 05N TO 23N BETWEEN 100W AND 115W. THIS 
DIFFLUENCE IS ENHANCING THE CONVECTION ASSOCIATED WITH TD TEN-E 
AND THE CONVECTION TO THE S OF THE DEPRESSION. MOST OF THE 
RESULTANT DENSE UPPER DEBRIS MOISTURE IS ADVECTED SW TO ALONG 
03N BETWEEN 100W AND 118W. THE DEBRIS MOISTURE FROM THE 
PREVIOUSLY MENTIONED CONVECTION ALONG THE CENTRAL MEXICAN COAST 
AND NEAR THE BAJA PENINSULA IS SPREADING ANTICYCLONICALLY NW 
AROUND THE MEXICAN UPPER RIDGE AXIS...AND BACK E OVER THE SEA OF 
CORTEZ AS FAR N AS 30N. 

A BROAD INVERTED UPPER TROUGH IS NOTED OVER THE FAR SE PORTION 
OF THE DISCUSSION AREA EXTENDING N FROM AN UPPER CYCLONE S OF 
THE AREA AT 02S91W. ASSOCIATED WEAK UPPER DIFFLUENCE EITHER SIDE 
OF THIS UPPER TROUGH IS SUPPORTING THE WESTWARD MOVING 
CONVECTION ALONG THE E SEGMENT OF THE MONSOON TROUGH AS 
PREVIOUSLY MENTIONED. SOME OF THE DEBRIS MOISTURE IS NOW 
ADVECTED S ACROSS THE EQUATOR BETWEEN 93W AND 100W. AN UPPER 
RIDGE EXTENDS E TO W ACROSS THE EXTREME SW CARIBBEAN AND THE 
UPPER FLOW TAPS THE DEBRIS MOISTURE FROM MONSOON CONVECTION E OF 
85W AND SPREADS IT NE ACROSS COSTA RICA AND NICARAGUA OVER THE W 
CARIBBEAN REACHING NEAR JAMAICA BEFORE IT EVAPORATES. 

ELSEWHERE AT THE LOW LEVELS...SURFACE HIGH PRESSURE IS CENTERED 
N OF THE AREA NEAR 35N148W AND IS PRODUCING LIGHT TO MODERATE NE 
FLOW ACROSS THE AREA W OF THE REMNANTS OF TROPICAL CYCLONE 
ILEANA. 

$$
NELSON