000
AXPZ20 KNHC 101523
TWDEP 

TROPICAL WEATHER DISCUSSION 
NWS TPC/NATIONAL HURRICANE CENTER MIAMI FL
1605 UTC SAT APR 10 2010

TROPICAL WEATHER DISCUSSION FOR THE EASTERN PACIFIC OCEAN FROM 
THE EQUATOR TO 32N...EAST OF 140W. 

BASED ON 1200 UTC SURFACE ANALYSIS AND SATELLITE IMAGERY THROUGH 
1500 UTC.

...ITCZ...

AXIS IS CENTERED ALONG 04N77W TO 06N85W TO 02N110W TO 06N120W TO 
02N132W TO 04N140W. SCATTERED STRONG WITHIN 90 NM OF THE AXIS E 
OF 80W. SCATTERED MODERATE ISOLATED STRONG WITHIN 90-120 NM OF 
THE AXIS BETWEEN 89W AND 114W. SCATTERED MODERATE WITHIN 120 NM 
OF THE AXIS BETWEEN 118W AND 127W. 

...DISCUSSION...

BROAD MID/UPPER LEVEL TROUGH COVERS THE EXTREME N PORTION OF THE 
DISCUSSION AREA BETWEEN 115W AND 140W WITH SEVERAL EMBEDDED 
SHORTWAVES NOTED. THE MOST SIGNIFICANT SHORTWAVE LOCATED WELL N 
OF THE AREA ALONG 136W IS SWINGING SE DOWN THE BACKSIDE OF THE 
MEAN TROUGH AND IN CONJUNCTION WITH A LARGE CLOSED UPPER LOW  
FORECAST TO DROP S FROM THE GULF OF ALASKA IS HELPING TO AMPLIFY 
THE TROUGH. THIS SHORTWAVE IS PROVIDING SUPPORT FOR A FAIRLY 
STRONG COLD FRONT THAT IS FORECAST TO ENTER THE AREA WITHIN 12 
HOURS AND SWEEP SE ACROSS THE NW HALF OF THE AREA BY MON WITH AN
INCREASE IN NW SWELLS OF UP TO 14 FT.  

S OF 25N...A BROAD MID/UPPER LEVEL RIDGE IS NOTED GENERALLY W OF 
95W WITH AN ASSOCIATED ANTICYCLONE NEAR 9N123W. A SUBTROPICAL 
JET STREAM BRANCH ENTERS THE AREA NEAR 25N140W AND CONTINUES EWD 
THROUGH 22N130W TO 22N120W AND ACROSS CENTRAL MEXICO. THE JET IS 
TRANSPORTING UPPER LEVEL MOISTURE IN THE FORM OF SCATTERED TO 
BROKEN CIRRUS CLOUDS EWD ACROSS THE AREA TO CENTRAL MEXICO.
SATELLITE DERIVED WINDS INDICATED JET CORE SPEEDS OF IN EXCESS 
OF 150 KT W OF 130W.  

ACROSS THE DEEP TROPICS...CONVECTION REMAINS VERY ACTIVE ALONG 
THE ITCZ W OF 110W AND IS HELPING TO MAINTAIN THE ABOVE AREA
OF BROAD MID/UPPER LEVEL RIDGING. WITH UPPER LEVEL DIFFLUENCE
CONTINUING TO HOLD S OF THE RIDGE...EXPECT CONVECTION NEAR AND 
ALONG THE ITCZ TO REMAIN ACTIVE W OF ABOUT 110W THROUGH THE NEXT 
48 HRS. 

OVER THE FAR EASTERN PART OF THE AREA...A NARROW MID/UPPER SHEAR
AXIS EXTENDS FROM WRN HONDURAS SW TO 11N97W. ONLY ISOLATED 
SHOWERS ARE NOTED NEAR THE TROUGH AS UPPER LEVEL SUBSIDENCE ACTS 
TO SUPPRESS CONVECTIVE ACTIVITY. A MID/UPPER LEVEL RIDGE IS TO 
THE SE OF THE TROUGH ALONG 7N EXTENDING EWD TO ACROSS S AMERICA. 
SCATTERED MODERATE/ISOLATED STRONG CONVECTION IS ACTIVE UNDER 
THE RIDGE ALONG THE ITCZ E OF 79W TO INLAND THE COLOMBIAN COAST.

AT THE SURFACE...A RIDGE EXTENDS ACROSS THE AREA THROUGH 29N140W 
TO 21N115W AND IS GRADUALLY SLIDING TO THE S WITH TIME. THE PRES 
GRADIENT BETWEEN THE RIDGE AND LOWER PRES ASSOCIATED WITH THE 
ITCZ HAS WEAKENED DURING THE PAST 24 HOURS...WITH ONLY A SMALL 
AREA OF NE WINDS OF 20 KT REMAINING FROM 4N-15N W OF 130W. A 
TIGHT PRES GRADIENT REMAINS BETWEEN THE AFOREMENTIONED RIDGE AND 
LOWER PRES OVER THE SW U.S. RESULTING IN A LARGE AREA OF NW 
20-30 KT WINDS JUST N OF THE AREA E OF 128W. THE HIGH IS 
FORECAST TO SLIDE SE AND SLIGHTLY WEAKEN THROUGH THE NEXT 24-48 
HRS ALLOWING FOR THE PRES GRADIENT TO COMPLETELY RELAX AND WINDS 
TO DIMINISH. THE COLD FRONT NOTED ABOVE WILL PUSH INTO THE NW 
SECTION OF THE AREA IN 12 HOURS THEN WEAKEN AS IT EXTENDS FROM 
NEAR 30N121W TO 22N140W IN ABOUT 48 HOURS. WINDS AHEAD AND 
BEHIND THE FRONT WILL INCREASE TO 20-25 KT...BUT QUICKLY 
DIMINISH TO 20 KT IN 48 HRS AS PRES GRADIENT WEAKENS AS WEAK 
HIGH PRES SETTLES IN OVER THE AREA.

GAP WINDS...
FRESH TO STRONG TRADES OVER THE CARIBBEAN SEA CONTINUE TO FUNNEL 
W ACROSS THE GULF OF PAPAGAYO RESULTING IN NE 20-30 KT WINDS
AS SUPPORTED BY A HIGH RESOLUTION ASCAT PASS FROM 0335 UTC LAST
NIGHT. MODEL GUIDANCE SHOWS THAT THESE WINDS WILL CHANGE LITTLE
THROUGH THE NEXT 24 HRS...THEN DECREASE TO 20 KT IN 48 HRS AS 
THE WRN CARIBBEAN TRADES WEAKEN QUITE SIGNIFICANTLY.
  
A TIGHT PRES GRADIENT ANALYZED ACROSS SE MEXICO IS ALLOWING
FOR N TO NE WINDS IN THE RANGE OF 20-25 KT TO FUNNEL S THROUGH 
THE GULF OF TEHUANTEPEC WITHIN 45 NM EITHER SIDE OF A LINE FROM 
16N94.5W TO 14N95W TO 13N97W. MODEL GUIDANCE INDICATES THAT THE 
N TO NE WINDS WILL CONTINUE THROUGH THE NEXT 24 HRS AT THESE
SPEEDS...BUT DIMINISH IN AREAL COVERAGE AND BE CONFINED TO N OF 
14N BETWEEN 94W AND 96W WITH SEAS TO 8 FT BY 36 HOURS. 

FOR ADDITIONAL INFORMATION PLEASE VISIT 
HTTP://WWW.HURRICANES.GOV/MARINE

$$
COBB