000
AXPZ20 KNHC 202154
TWDEP 

TROPICAL WEATHER DISCUSSION
NWS NATIONAL HURRICANE CENTER MIAMI FL
2205 UTC WED FEB 20 2013

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 1800 UTC SURFACE ANALYSIS AND SATELLITE IMAGERY THROUGH 
2100 UTC.

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

NO MONSOON TROUGH IS PRESENT. THE INTERTROPICAL CONVERGENCE AXIS 
EXTENDS FROM 01N81W TO 04N90W TO 03N99W TO 04N125W TO 07N140W. 
SCATTERED MODERATE CONVECTION IS N OF THE ITCZ TO 09N BETWEEN 
130W AND 135W.

...DISCUSSION...

A RATHER VIGOROUS UPPER LEVEL LOW ON THE THE SOUTHERN PORTION OF 
A LARGE UPPER TROUGH OVER THE WESTERN CONUS IS MOVING SE ACROSS 
SOUTHERN CALIFORNIA AND SOUTHERN ARIZONA. THIS FEATURE SUPPORTS 
A SURFACE COLD FRONT THAT EXTENDS FROM THE NORTHERN BAJA 
CALIFORNIA PENINSULA NEAR 29N114W TO 26N123W TO 30N133W. HIGHLY 
AMPLIFIED DEEP LEVEL RIDGING TO THE W OF THE LOW IS REFLECTED AS 
A NEARLY STATIONARY STRONG 1037 MB HIGH CENTER NW OF THE AREA AT 
36N148W WITH AN ASSOCIATED RIDGE STRETCHING SE THROUGH 32N140W 
TO 23N120W TO 12N101W. 

WATER VAPOR SATELLITE IMAGERY DEPICTS A RATHER BROAD AREA OF MID 
TO UPPER LEVEL LOW PRES WELL W OF THE DISCUSSION AREA NE OF THE 
HAWAIIAN ISLANDS NEAR 27N149W. VERY MOIST AND DIVERGENT MID TO 
UPPER LEVEL SW FLOW BETWEEN THIS FEATURE AND THE UPPER TROUGH 
OVER THE WESTERN CONUS IS ADVECTING AMPLE DEEP ATMOSPHERIC  
MOISTURE TO THE NE-E ACROSS THE AREA W OF ABOUT 125W. THE 
SOUTHERN LEG OF THIS MOSITURE IS CONFINED TO S OF 24N BETWEEN 
118W AND 130W. E OF 118W THE MOISTURE PLUME THINS OUT...BUT 
ENOUGH OF IT REMAINS TO REACH TO OVER CENTRAL MEXICO...AND NE TO 
ACROSS THE NORTHERN GULF OF MEXICO.

THE AFOREMENTIONED COLD FRONT WILL QUICKLY MOVE E-SE WHILE 
DISSIPATING JUST E OF THE AREA BY THU AFTERNOON. THE VERY 
TIGHT PRES GRADIENT IN ITS WAKE IS LEADING TO NW-N WINDS OF 
20-30 KT AS WAS SUGGESTED BY RECENT ASCAT AND WINDSAT 
SCATTEROMETER PASSES. LARGE SEAS OF 11-16 FT IN NW SWELLS ARE 
FOLLOWING IN BEHIND THE FRONT. SW OF THE FRONT AND RIDGE... 
FRESH TO STRONG NE-E WINDS COVER THE W CENTRAL WATERS ALONG WITH 
COINCIDENT 9-13 FT SEAS. A SURROUNDING AREA OF 8-11 FT NW SWELL 
IS ELSEWHERE N OF A LINE FROM 03N140W TO 06N115W TO 28N115W. 
WINDS IMMEDIATELY BEHIND THE FRONT WILL DIMINISH TO MODERATE TO 
FRESH BY THU AFTERNOON...WHILE THE LARGEST SWELLS DECAY TO 13 FT 
BY THEN...AND THEN TO 12 FT BY FRI AFTERNOON. 

FRESH TO STRONG SW TO W WINDS WILL PRECEDE THE FRONT OVER THE 
NORTHERN PORTION OF THE GULF OF CALIFORNIA N OF 28N...HOWEVER 
THESE WINDS WILL DIMINISH TO 20 KT OR LESS BY LATE TONIGHT AS 
THE FRONT WEAKENS.
 
GAP WINDS...
FRESH TO STRONG WINDS WILL CONTINUE TO PULSE IN THE GULF OF 
PAPAGAYO...WITH THE STRONGEST WINDS OCCURRING DURING THE 
OVERNIGHT AND EARLY MORNING HOURS WITH ENHANCEMENT BY NOCTURNAL 
DRAINAGE FLOW. ASSOCIATED SIGNIFICANT WAVE HEIGHTS WILL PEAK TO 
AROUND 9 FT. THE AREAL COVERAGE OF THESE WINDS WILL SHRINK TO E 
OF 88W BY FRI AFTERNOON...AND LIKELY TO MODERATE TO FRESH LEVELS 
OVERALL THIS WEEKEND AS CONDITIONS BECOME LESS FAVORABLE.
 
NORTHERLY WINDS HAVE DIMINISHED TO MODERATE IN THE GULF OF 
TEHUANTEPEC...AND WINDS WILL BECOME SE-S AT LIGHT TO MODERATE 
LEVELS TONIGHT THROUGH EARLY NEXT WEEK.

$$
LEWITSKY