000
AXPZ20 KNHC 042205
TWDEP 

TROPICAL WEATHER DISCUSSION  
NWS TPC/NATIONAL HURRICANE CENTER MIAMI FL
2205 UTC FRI APR 04 2008

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 2145 UTC.

...ITCZ...

ITCZ AXIS IS CENTERED ALONG 9N85W 4N100W 2N110W 3N120W 3N130W 
3N140W. SCATTERED MODERATE/ISOLATED STRONG CONVECTION IS WITHIN
60 NM S OF THE AXIS BETWEEN 119W-122W.

...DISCUSSION...

UPPER LEVEL W-NW FLOW IS PRESENT OVER THE ERN PART OF THE AREA
N OF 20N E OF 120W IN THE WAKE OF A MID/UPPER LEVEL TROUGH THAT
MOVED INLAND THE WRN UNITED STATES DURING THE PAST COUPLE OF 
DAYS. AT THE SURFACE...NW-N WINDS TO 20 KT WITH SEAS TO 8 FT
ARE BEING OBSERVED N OF 19N E OF 116W INCLUDING THE GULF OF 
CALIFORNIA. A MID/UPPER LEVEL RIDGE AXIS EXTENDS FROM 32N122W
S THROUGH 25N122W TO A LARGE AND QUASI-STATIONARY MID/UPPER
LEVEL ANTICYCLONE ANCHORED NEAR 13N121W. THE RIDGE HAS 
PRACTICALLY FORMED DUE TO THE AMPLIFICATION OF A RATHER BROAD 
TROUGH THAT IS W OF THE REGION ROUGHLY ALONG 144W. MID/UPPER
LEVEL MOISTURE ORIGINATING FROM THE DEEP CENTRAL TROPICAL 
PACIFIC IS BEING CHANNELED NEWD INTO THE AREA UP AND AROUND
THE NRN PERIPHERY OF THE RIDGE AND TOWARDS BAJA CALIFORNIA AND
CENTRAL MEXICO.

THE TROUGH IS PART OF AN ELONGATED CYCLONIC VORTEX W OF THE AREA
MOVING SLOWLY SSW NEAR 26N149W. THE ASSOCIATED SURFACE SYSTEM 
CONSISTS OF A 1016 MB LOW NEAR 26N150W WITH AN OCCLUDED FRONT 
TO 24N145W WHERE IT BECOMES STATIONARY TO SE OF THE HAWAIIAN 
ISLANDS. THE LOW IS STATIONARY. BROKEN LOW AND MID LEVEL CLOUDS 
WITH WIDELY SCATTERED SHOWERS AND ISOLATED WEAK CONVECTION ARE 
WITHIN 75 NM EITHER SIDE OF THE FRONT. THE TYPICAL TRADE WIND 
BELT ZONE CONTINUES TO BE RATHER SMALL IN AREAL COVERAGE 
EXTENDING FROM 9N-18N W OF 125W WITH SEAS RUNNING UP TO 8 FT. 

THE UPPER LEVEL CYCLONIC VORTEX IS FORECAST TO DROP S THROUGH 
THE NEXT 48 HRS...THEN LIFT NE TOWARDS THE FAR NW CORNER OF THE 
AREA BY SUN...WHILE THE COLD FRONT STALLS JUST W OF THE AREA. 
EXPECT WINDS TO INCREASE OVER THE NW PART BEGINNING LATE FRI 
INTO SAT AS HIGH PRES N OF THE AREA BUILDS S CAUSING A SQUEEZE 
PLAY WITH LOW PRES ASSOCIATED WITH THE FRONT TIGHTENING THE PRES 
GRADIENT THERE WITH SE WINDS FORECAST TO INCREASE TO 20-25 KT
...AND CONTINUE THROUGH EARLY NEXT WEEK BEFORE DIMINISHING TO 
15-20 KT AS A RIDGE THEN BUILDS SE THROUGH 32N133W 20N117W. NW 
FLOW ALONG AND JUST W OF THE BAJA CALIFORNIA COAST IS EXPECTED 
TO CONTINUE OVER THE NEXT FEW DAYS AS THE PRES DIFFERENCE 
BETWEEN LOW PRES OVER THE SW UNITED STATED AND THE RIDGE ALLOW 
SUSTAIN A GRADIENT ADEQUATE TO SUPPORT THESE WINDS.

THE ANTICYCLONE MENTIONED ABOVE NEAR 13N121W ALSO HAS A RIDGE 
EXTENDING SE TO 5N105W. WATER VAPOR IMAGERY CONTINUES TO 
INDICATE STRONG SUBSIDENCE UNDERNEATH THE RIDGE ACROSS THIS 
AREA...INHIBITING NOT ONLY ANY CONVECTION BUT NEARLY ALL CLOUD 
COVER. ONLY ISOLATED SHOWERS AND TSTMS ARE NOTED FROM 6N-13N 
BETWEEN 89W-98W MAINLY ASSOCIATED WITH THE ITCZ...AND WITH 
A SURFACE TROUGH SLOWLY MOVING W FROM 7N93W TO 2N98W. A COL
REGION IS NOTED SW OF THE ANTICYCLONE NEAR 5N134W...WHICH
IS S OF A POINT WHERE THE UPPER LEVEL FLOW TRANSITIONS FROM
CYCLONIC TO ANTICYCLONIC TO ITS N AND NE. UPPER LEVEL DIFFLUENCE
OCCURRING ON THE SW PERIPHERY OF THE ANTICYCLONE IS ENHANCING
ITCZ CONVECTION BETWEEN 128W-131W. A LOW LEVEL TROUGH MOVING
W ABOUT 15 KT MAY BE IN THAT VICINITY AS WELL.

TO THE NE OF THE ANTICYCLONE...A JET STREAM BRANCH IS LOCATED 
OVER THE NRN PERIPHERY OF THE ANTICYCLONE FROM 24N122W EXTENDING 
ESE TO ACROSS SRN BAJA CALIFORNIA AND CENTRAL MEXICO. MAXIMUM 
WINDS WITH THE JET ARE IN THE RANGE OF 60-70 KT IN THE EXIT 
REGION FOUND BETWEEN SRN BAJA AND THE COAST OF CENTRAL MEXICO.

THE TAIL END OF AN UPPER LEVEL TROUGH OVER THE CENTRAL CARIBBEAN
SEA EXTENDS SW TO ACROSS HONDURAS AND NICARAGUA AND TO THE FAR
E PACIFIC WATERS NEAR 7N90W. IT IS AIDING CONVECTION ALONG THE
ITCZ NEAR THE SURFACE TROUGH ALONG 7N93W 2N98W.

NWP MODELS CONTINUE TO FORECAST THE ANTICYCLONE NEAR 13N121W TO
MOVE WWD WITHIN THE NEXT FEW DAYS AS HEIGHTS LOWER OVER MEXICO 
AND THE GULF OF MEXICO...WHILE THE TROUGH LIFTS NE AND DAMPENS 
OUT OVER THE NRN CARIBBEAN. MID/UPPER LEVEL FLOW THEN BECOMES 
ZONAL OVER JUST ABOUT THE ENTIRE DISCUSSION AREA...EXCEPT FOR 
THE FAR NW CORNER WHERE IT WILL BE UNDER THE AFFECTS OF THE 
UPPER LEVEL LOW NEARING THAT PORTION OF THE AREA.

GAP WINDS ARE EXPECTED TO BE ON THE QUIET SIDE WELL INTO NEXT 
WEEK.
   
$$
AGUIRRE