000
AXPZ20 KNHC 171012
TWDEP 

TROPICAL WEATHER DISCUSSION  
NWS NATIONAL HURRICANE CENTER MIAMI FL
1005 UTC THU FEB 17 2011

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

BASED ON 0600 UTC SURFACE ANALYSIS AND SATELLITE IMAGERY THROUGH 
0900 UTC.

...ITCZ...
AXIS FROM 04N114W TO 06N128W TO 05N135W TO 06N140W. SCATTERED 
MODERATE ISOLATED STRONG CONVECTION NOTED WITHIN 120 NM OF AXIS 
BETWEEN 130W AND 135W.

...DISCUSSION...
LARGE AMPLITUDE DEEP LAYER LONGWAVE TROUGH CENTERED OVER NE PAC 
EXTENDING INTO AREA THROUGH 30N128W TO 12N140W. TROUGH SUPPORTS 
A WEAKENING COLD FRONT FROM 30N117W TO 24N130W MOVING SE...BUT 
SLOWING DOWN. A STRONG SHORTWAVE IS FORECAST TO DIVE THROUGH 
BACKSIDE OF TROUGH THIS AFTERNOON AND TONIGHT AND USHER INTO NW 
PORTIONS A FAST-MOVING COLD FRONT..WHICH WILL EFFECTIVELY MERGE 
WITH FIRST FRONT ALONG NW COAST OF BAJA CALIFORNIA SAT. THIS 
SECOND COLD FRONT MUCH STRONGER WITH STRONG SW FLOW AHEAD OF 
BOUNDARY AND LARGE LONG PERIOD SWELLS BEHIND IT RAISING WAVE 
HEIGHTS TO 15 FT FRI NIGHT. ASSOCIATED FRESH WINDS SHOULD REMAIN 
N OF 25N BUT LARGE SWELLS WILL SPREAD S OF 20N BY LATE FRI. A 
BROAD RIDGE PERSISTS E OF THE TROUGH WITH CREST ACROSS N MEXICO 
AND TEXAS ALONG 103W AND MAINTAINS A GENERALLY DRY AND STABLE 
ENVIRONMENT E OF 110W. MODEL GUIDANCE NUDGES RIDGE AXIS SLIGHTLY 
E WHILE AXIS BECOMES MORE SW TO NE TILED THROUGH SAT AS SERIES 
OF SHORT WAVES CONTINUE TO MOVE OVER THE RIDGE THROUGH FORECAST 
PERIOD AND BEYOND. A MID LEVEL REFLECTION OF THE ATLC TUTT 
SNAKES W-SW ACROSS THE NW CARIBBEAN AND CENTRAL AMERICA TO A 
WEAK MID LEVEL CYCLONE NEAR 14N95W...WITH STRONG SUBSIDENCE 
DOMINATING N OF 06N BETWEEN 90W AND 100W. DEEP AND ACTIVE 
CONVECTION ACROSS COLOMBIA AND MUCH OF NW S AMERICA IS ACTING TO 
MAINTAIN UPPER RIDGING ACROSS THE TROPICS E OF 90W. 

ELSEWHERE AT THE SURFACE...
FRESH N TO NW WINDS ALONG THE S HALF OF THE W COAST OF BAJA 
CALIFORNIA CONTINUE AS MERGING FRONTS TIGHTEN GRADIENT AGAINST 
COASTAL MOUNTAINS. WINDS THERE AREA EXPECTED TO DIMINISH BY THU 
EVENING AS FRONT SHIFTS NE IN RESPONSE TO UPPER LEVEL 
SHORTWAVE.  

FRESH TO STRONG NE TRADES W OF 135W WILL WEAKEN AS HIGH PRES 
RIDGE IS FORCED E BY MERGED COLD FRONTS. NEVERTHELESS...THE 
AFOREMENTIONED LARGE NW SWELLS SPREAD S WITH 10 FT SEAS REACHING 
10N W OF 115W.  

FRESH BREEZE CONTINUE TO PULSE THROUGH GULF OF PAPAGAYO OVER 
NEXT COUPLE OF DAYS...PRIMARILY DURING EARLY MORNING MOUNTAIN 
DRAINAGE HOURS.

NELY FLOW WILL SET UP IN THE SRN GULF OF MEXICO FRI NIGHT 
THROUGH SAT AND ALLOW NLY WINDS 20 TO 25 KT TO RETURN TO THE 
GULF OF TEHUANTEPEC.

EPAC ITCZ HAS TRANSITIONED AND SHIFTED INTO THE SRN HEMISPHERE E 
OF 110W DURING THE PAST FEW DAYS...AND IS FORECAST TO REMAIN IN 
THIS CONFIGURATION FOR THE NEXT FEW DAYS. 

$$
STRIPLING