000
AXPZ20 KNHC 101019
TWDEP 

TROPICAL WEATHER DISCUSSION  
NWS NATIONAL HURRICANE CENTER MIAMI FL
1005 UTC SAT MAR 10 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 0945 UTC.

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

THE PRIMARY ITCZ AND ASSOCIATED CONVECTION WAS JUST S OF THE 
EQUATOR. LOW LEVEL WINDS IDENTIFIED A SMALL ITCZ SEGMENT
FROM 03N93W TO NEAR 01N107W. NO MONSOON TROUGH WAS ANALYZED.
SCATTERED MODERATE/ISOLATED STRONG CONVECTION WAS WITHIN 45 NM 
OF THE ITCZ.

...DISCUSSION...

A LARGE UPPER CUTOFF LOW WAS OVER THE DESSERT SW SECTION OF
THE U.S. WITH A TROUGH SW TO ACROSS NORTHERN BAJA CALIFORNIA AND 
S TO NEAR 22N117W. RATHER BROAD MID/UPPER LEVEL RIDGING WAS 
PRESENT OVER THE REMAINDER OF THE AREA WITH A RIDGE CREST 
IDENTIFIED FROM 27N129W TO NE WELL OVER THE INTERIOR WESTERN 
U.S. A BROAD UPPER TROUGH WAS ADVANCING EASTWARD JUST N OF THE 
AREA W OF THE 130W. SATELLITE WATER VAPOR IMAGERY SHOWED AN 
EXPANSIVE AREA OF MODERATE SUBSIDENCE OVER THE EASTERN SECTION 
OF THE AREA MAINTAIN VERY STABLE ATMOSPHERIC CONDITIONS THERE 
WITH MOSTLY CLEAR SKIES. A VIGOROUS UPPER LEVEL LOW WELL W OF 
THE AREA TO THE WNW OF THE HAWAIIAN ISLANDS WAS ACCOMPANIED BY
A VERY LARGE SWATH OF DEEP LAYER ATMOSPHERIC MOISTURE TO ITS E 
AND SE. STRONG UPPER LEVEL SW WINDS WERE ADVECTING THIS MOISTURE 
NE TO JUST OVER THE FAR WESTERN BOUNDARY OF THE DISCUSSION AREA. 

THE CUTOFF LOW OVER THE SW U.S. WILL GRADUALLY LIFT NE THROUGH 
SUN IN RESPONSE TO INTENSIFYING SHORTWAVE ENERGY THAT SWINGS IN 
FROM NE PACIFIC TO INLAND THE PACIFIC NW. THIS WILL ALSO ACT TO 
FLATTEN THE RIDGE...AND THUS THE THE UPPER LEVEL LARGE-SCALE 
WIND FLOW IS FORECAST TO BECOME COMPARATIVELY MORE ZONAL WITHIN 
THE NEXT 48 HRS. A WEAK COLD FRONT THAT MOVED INTO THE FAR NW 
CORNER OF THE AREA EARLIER WILL NOT ADVANCE EASTWARD MUCH THROUGH
SUN AS THE BROAD UPPER TROUGH JUST TO ITS N QUICKLY TRANSLATES 
EASTWARD AS THE SHORTWAVE TROUGH MOVES THROUGH ITS FAR NORTHERN 
PERIPHERY. THE FRONT IS FORECAST TO SLOWLY WASH OUT THROUGH SUN 
AS STRONG HIGH PRES BUILDS EASTWARD ACROSS THE NORTHERN WATERS 
UNDER THE UPPER LEVEL ZONAL FLOW. THE MAIN ISSUE WITH
RESPECT TO MARINE INTERESTS OVER THE THE NW AND N CENTRAL 
WATERS WILL BE THE ARRIVAL OF LARGE LONG PERIOD NW SWELLS
TODAY AND INTO EARLY SUN. THESE SWELLS ARE FORECAST BY 
SOME OF THE WAVEWATCH MODEL GUIDANCES TO PRODUCE SEAS OF 
12 OR 13 FT...WHILE OTHER WAVE MODELS ARE A BIT LOWER WITH 
THE WAVE HEIGHTS.

OVER THE FAR EASTERN PORTION OF THE AREA...AN UPPER LEVEL TROUGH 
WAS NOTED TO STRETCH FROM THE WESTERN CARIBBEAN SEA SW TO ACROSS 
COSTA RICA AND PANAMA AND TO NEAR 01N85W. HOWEVER...EXTENSIVE 
SUBSIDING OBSERVED OVER THIS PART OF THE AREA WAS INHIBITING 
SHOWERS/TSTMS FROM DEVELOPING THERE. 

ELSEWHERE AT THE SURFACE...A RIDGE EXTENDED THROUGH 32N135W SE
TO 25N121W TO 18N111W. HIGH PRES WAS GENERALLY PRESENT N OF 15N 
W OF 112W. A TIGHT PRES GRADIENT TO THE S OF THE RIDGE WAS
INDUCING NE-E 20-25 KT TRADE WINDS FROM 05N-21N W OF 120W...
AND FROM 07N-18N BETWEEN 112W AND 120W WITH SEAS OF 9-11 FT.
THIS AREA OF TRADES IS FORECAST TO CHANGE LITTLE OVER THE 
NEXT 24 HRS...THEN PERHAPS DIMINISH BOTH IN AREAL COVERAGE
AND IN WIND SPEEDS BY 48 HRS AS THE WEAKENS SOME IN RESPONSE
TO A COLD FRONT THAT SKIRTS THE FAR NORTHERN WATERS AT THAT
TIME.

COMPOSITE TPW IMAGERY INDICATED POSSIBLE LOW AMPLITUDE TROUGHS 
TO BE IN THE VICINITY OF 107W AND 135W MOVING WESTWARD AT 15-20 
KT. SCATTERED SHOWERS AND ISOLATED TSTMS ARE ALONG AND NEAR 
THESE TROUGHS.

GAP WINDS... 
THE GULF OF TEHUANTEPEC...N-NE GALE FORCE WINDS OF 35 KT ARE 
FORECAST TO LAST ONLY ABOUT 12 HRS AS THE TIGHT PRES GRADIENT 
OVER SE MEXICO SLACKENS. THESE WINDS THEN DIMINISH TO 20 KT IN 
24 HRS...AND TO LESS THAN 20 KT IN 36 HRS.

THE GULF OF PAPAGAYO...COASTAL LAND STATIONS IN NORTHWESTERN 
COSTA RICA REVEALED NE 20-25 KT WINDS LAST NIGHT. THESE WINDS 
REACHED AS FAR WEST AS 90W IN THE EASTERN PACIFIC. A LARGE AREA 
OF NORTHEASTERLY SWELL HAS BEEN ESTABLISHED IN THE TROPICAL 
NORTH PACIFIC OCEAN TO 110W DUE TO THE COMBINED INFLUENCE OF THE 
EARLIER TEHUANTEPEC AND PAPAGAYO GAP WIND EVENTS. HIGH PRES 
WILL BUILD TO THE NORTH OF THE CARIBBEAN SEA SUSTAINING STRONG 
TRADE WINDS IN THE CARIBBEAN. SUBSEQUENT GAP WINDS WILL LAST FOR 
THE NEXT 48 HOURS WITH POSSIBLE BRIEF INSTANCES OF 30 KT.

THE GULF OF PANAMA...STRONG TRADE WINDS IN THE SOUTHWESTERN 
CARIBBEAN SEA WILL MAINTAIN SPURTS OF FRESH NORTHERLY FLOW 
ACROSS THE PANAMA ISTHMUS AND INTO THE BAY OF PANAMA THROUGH THE 
NEXT 48 HOURS. AN ASCAT PASS FROM 0212 UTC LAST NIGHT REVEALED
EVIDENCE OF THESE WINDS ALREADY IN PLACE.

THE GULF OF CALIFORNIA...A TIGHT SURFACE PRES GRADIENT 
EXISTS IN THE GULF OF CALIFORNIA...BETWEEN HIGH PRESSURE THAT IS 
IN THE NORTH CENTRAL WATERS AND LOWER PRES THAT IS IN 
NORTHWESTERN MEXICO. THIS GRADIENT WAS RESULTING IN 
NW 20-25 KT WINDS FROM 23N TO 28N. THE WINDS WILL DIMINISH TO 20 
KT IN ABOUT 24 HRS AND TO LESS THAN 20 KT IN 36 HRS.

$$
AGUIRRE