000
AXPZ20 KNHC 291001
TWDEP 

TROPICAL WEATHER DISCUSSION
NWS NATIONAL HURRICANE CENTER MIAMI FL
1005 UTC TUE MAY 29 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 0600 UTC SURFACE ANALYSIS AND SATELLITE IMAGERY THROUGH 
0915 UTC.

...INTERTROPICAL CONVERGENCE ZONE/MONSOON TROUGH...
THE MONSOON TROUGH AXIS EXTENDS FROM COLOMBIA NEAR 09N73W TO 
10.5N82W TO 07.5N94W TO 12N108W TO LOW PRES NEAR 08N114W 1009 MB 
TO 07N127W...THEN TRANSITIONS TO ITCZ AXIS...CONTINUING ON TO 
BEYOND 08N140W. SCATTERED MODERATE ISOLATED STRONG CONVECTION 
NOTED FROM 03.5N TO 08N E OF 83W. ISOLATED TO SCATTERED 
CONVECTION NOTED WITHIN 90 NM EITHER SIDE OF TROUGH FROM 92W TO 
111W. SCATTERED MODERATE ISOLATED STRONG CONVECTION FROM 05N TO 
10N BETWEEN 111W AND 125W.

...DISCUSSION...

A SHARP MIDDLE/UPPER TROUGH CONTINUES NE TO SW ACROSS THE NW 
WATERS FROM 32N133W TO 23N143W THEN CONTINUES W-NW JUST N OF THE 
HAWAIIAN ISLAND CHAIN. GLOBAL MODELS ARE FORECASTING A VIGOROUS 
UPPER LOW TO PINCH OFF WITHIN THE TROUGH JUST E OF THE HAWAIIAN 
ISLANDS OVER NEXT THE TWO DAYS...AND IN TURN ALLOW FOR A WWD 
SHIFT OF THE UPPER RIDGE CURRENTLY CENTERED 108W-110W. THIS 
DEVELOPING LOW ALOFT WILL ALSO HELP TO WEAKEN THE SUBTROPICAL 
HIGH AT THE SURFACE THAT IS ALSO BEING ENCROACHED UPON BY A 
SYSTEM MAKING ITS WAY S OF THE ALEUTIAN ISLANDS. CURRENTLY...A 
1027 MB SUBTROPICAL HIGH NEAR 31N154W EXTENDS A RIDGE 
SOUTHEASTWARD THROUGH 30N128W TO 18N112W. THE HIGH WILL CONTINUE 
TO WEAKEN AS IT IS FORCED EASTWARD. THE FRESH TRADEWINDS TO THE 
S OF THIS RIDGE CURRENTLY EXTEND FROM SW PORTIONS OF THE AREA 
WWD INTO THE CENTRAL TROPICAL PACIFIC...AND WILL SHRINK 
SOUTHWESTWARD TO JUST N OF THE ITCZ IN RESPONSE TO THE WEAKENING 
HIGH THROUGH WED...WITH TRADES DIMINISHING TO A MODERATE BREEZE 
BY WED EVENING. 

THE PRES GRADIENT BETWEEN THE SUBTROPICAL HIGH AND TROUGHING 
OVER THE INTERMOUNTAIN WESTERN U.S. AND CENTRAL MEXICO IS 
GENERATING A SMALL AREA OF FRESH NW TO N WINDS OFFSHORE OF BAJA 
CALIFORNIA N OF 29N AS MEASURED BY A 0446 UTC ASCAT PASS. THESE 
CONDITIONS WILL REMAIN RELATIVELY UNCHANGED THROUGH 24 HOURS 
THEN EXPAND ON WED AS THE PRES GRADIENT TIGHTENS AS THE 
SUBTROPICAL HIGH MOVES EASTWARD AND TROUGHING BUILDS IN THE U.S. 
SOUTHWEST AND NORTH CENTRAL MEXICO. THIS WILL ALLOW FRESH NW TO 
N WINDS TO EXPAND SOUTHWARD ALONG THE COAST OF THE BAJA 
PENINSULA TO 24N.

A BROAD AND ELONGATED AREA OF LOW PRES EMBEDDED WITHIN THE 
MONSOON TROUGH IS CENTERED NEAR 09N113W...SHIFTING W IN A WAVE 
LIKE FASHION. MID-LEVEL CYCLONIC TURNING CONTINUES TO BE EVIDENT 
IN ANIMATED SATELLITE IMAGERY. A 0440 UTC ASCAT PASS REVEALED A 
WEAK LOW CENTER ALONG THE TROUGH NEAR 08N114W...AND VERY NEAR 
THE MID-LEVEL CENTER...WITH A SMALL REGION OF 20 KT NE WINDS TO 
THE NW OF THE LOW. SCATTERED MODERATE ISOLATED STRONG CONVECTION 
WAS OCCURRING FROM 05N TO 10N BETWEEN 111W AND 125W. THIS 
PERTURBATION WILL CONTINUE TO SHIFT WWD TODAY AND IS EXPECTED TO 
REMAIN VERY ACTIVE CONVECTIVELY THROUGH THIS EVENING...BEFORE 
BEGINNING TO SLOWLY WEAKEN OVER THE NEXT COUPLE OF DAYS. 

$$
STRIPLING