000
AXPZ20 KNHC 221614
TWDEP 

TROPICAL WEATHER DISCUSSION    
NWS TPC/NATIONAL HURRICANE CENTER MIAMI FL
1605 UTC SUN APR 22 2007

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 1200 UTC SURFACE ANALYSIS AND SATELLITE IMAGERY THROUGH 
1515 UTC.

...ITCZ...

ITCZ AXIS IS CENTERED ALONG 9N85W 8N98W 7N110W 5N120W 4N130W 
4N140W. SCATTERED MODERATE/ISOLATED STRONG CONVECTION IS WITHIN
60 NM N OF THE AXIS BETWEEN 106W-112W. SCATTERED MODERATE 
CONVECTION IS WITHIN 60 NM OF THE AXIS BETWEEN 136W-139W.

...DISCUSSION...

A RATHER VIGOROUS SHORTWAVE TROUGH OVER CALIFORNIA EXTENDS SWWD 
INTO THE DISCUSSION AREA THROUGH 32N117W AND CONTINUES SW TO 
AN ELONGATED MID/UPPER LEVEL CYCLONIC CIRCULATION NEAR 25N120W
MOVING ENE ABOUT 20 KT. THE TROUGH CONTINUES SW FROM THE 
CYCLONIC CIRCULATION TO 20N125W ...THEN EXTENDS W AS A SHEARED 
AXIS ALONG 19N131W TO 20N140W AND FURTHER W OF THE AREA TO THE 
HAWAIIAN ISLANDS. THE UPPER FLOW IS CYCLONIC IS CYCLONIC N OF 
THE TROUGH E OF 121W AND ANTICYCLONIC ELSEWHERE N OF THE TROUGH. 
STRONG SUBSIDENCE IS NOTED ON WATER VAPOR IMAGERY WITHIN 90 NM 
EITHER SIDE OF LINE 17N127W 19N135W TO 19N140W. MODERATE 
SUBSIDENCE IS PRESENT ELSEWHERE FROM 16N-26N W OF 126.5W. A
SUBTROPICAL JET STREAM BRANCH EXTENDS INTO THE REGION THROUGH 
16N140W AND CONTINUES E THROUGH 17N130W AND NE THROUGH 20N120W
TO ACROSS THE SRN TIP OF BAJA CALIFORNIA AND NEWD ACROSS NW 
MEXICO. MAXIMUM JET CORE WINDS AS INDICATED BY SATELLITE-DERIVED 
WINDS ARE IN THE 60-90 KT RANGE WITHIN 300 NM SE AND S OF 
THE JET BETWEEN 115W-127W. BROAD MID/UPPER LEVEL RIDGING 
DOMINATES THE SRN PORTION TO THE S OF THE JET STREAM AND W OF 
107W. UPPER LEVEL MOISTURE SEEN AS MOSTLY BROKEN HIGH CLOUDS
WITHIN 500 NM SE OF THE JET STREAM.

OVER THE ERN SECTION...THE FLOW BECOMES DIFFLUENT E OF 107W. 
ITCZ CONVECTION IS NOT AS ACTIVE AS YESTERDAY...BUT POCKETS
OF MODERATE CONVECTION ARE ACTIVE ALONG WITHIN 120 NM N OF
THE ITCZ. BROAD MID/UPPER LEVEL RIDGING CONTINUES ACROSS
THE NRN PART OF S AMERICA...AND OVER CENTRAL AMERICAN AND
THE SE PORTION OF MEXICO. ABUNDANT MODERATE SUBSIDENCE AND DRY
AIR ALOFT EXISTS HERE KEEPING DEEP CONVECTION TO A MINIMUM.

AT THE SFC...A STATIONARY 1026 MB HIGH CENTER IS ANALYZED W OF
THE DISCUSSION AREA NEAR 29N147W WITH A RIDGE EXTENDING ESE 
THROUGH 27N135W 25N122W TO 21N113W. HIGH PRES COVERS THE AREA N 
OF 15N W OF 112W. THE PRES GRADIENT RESULTING FROM THE RIDGE IS 
RESULTING IN NE TRADES OF 20 KT FROM 6N-21N W OF 1305W. NW WINDS 
TO 20 KT WERE NOTED ON A QUIKSCAT PASS FROM AROUND 1300 UTC TO 
BE CONFINED OVER THE NE PART OF THE AREA N OF 21N E OF 118W TO
ALONG THE COAST OF BAJA CALIFORNIA. THESE WINDS ARE EXPECTED TO 
DIMINISH AREAL COVERAGE IN 48 HRS AS A WEAK COLD FRONT MOVES
THROUGH THE NE PORTION DURING THE NEXT 24-36 HRS. EXPECT NE
WINDS TO 20 KT TO BEGIN ACROSS THE GULF OF PAPAGAYO IN 24 HRS
...AND LAST THROUGH MID WEEK.

$$
AGUIRRE