000
AXPZ20 KNHC 201536
TWDEP 

TROPICAL WEATHER DISCUSSION                                    
NWS NATIONAL HURRICANE CENTER MIAMI FL                         
1605 UTC FRI MAR 20 2015

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 1200 UTC SURFACE ANALYSIS AND SATELLITE IMAGERY THROUGH 
1430 UTC. 

...INTERTROPICAL CONVERGENCE ZONE/MONSOON TROUGH...
            
A WEAK MONSOON TROUGH EXTENDS FROM 1010 MB LOW PRES NEAR 
05.5N91W TO 1011 MB LOW PRES NEAR 03N106W TO 08.5N117W...WHERE 
IT TERMINATES. ITCZ EXTENDS FROM 06N127W TO BEYOND 06N140W. 
SCATTERED MODERATE ISOLATED STRONG CONVECTION NOTED WITHIN 120 
NM E SEMICIRCLE OF LOW PRES NEAR 05.5N91W.

...DISCUSSION... 

VERY TRANQUIL MARINE AND WEATHER CONDITIONS PERSIST ACROSS THE 
AREA THIS MORNING. A 1023 MB HIGH PRESSURE WAS CENTERED NEAR 
29N128W WITH RIDGE EXTENDING FROM THE HIGH SE TO NEAR 20N111W. A 
VERY MODEST PRES GRADIENT CURRENTLY PREVAILS BETWEEN THE HIGH 
AND LOW PRES NEAR THE ITCZ...YIELDING NE TRADEWINDS 15 TO 20 KT 
GENERALLY S OF 23N AND W OF 117W. THE PRES GRADIENT TO THE E OF 
THE HIGH WAS ONLY YIELDING N TO NNW WINDS 10 TO 15 KT ALONG THE 
W COAST OF BAJA CALIFORNIA...WITH OVERNIGHT SCATTEROMETER DATA 
INDICATING WINDS AROUND 15 KT ALONG COASTAL SECTIONS NEAR CABO 
SAN LAZARO. THE HIGH PRESSURE WILL SHIFT SLIGHTLY EASTWARD OVER 
THE UPCOMING WEEKEND AND ACT TO TIGHTEN THE PRESSURE GRADIENT 
MODESTLY BOTH SOUTH AND EAST OF THE RIDGE...WHICH WILL 
STRENGTHEN THE TRADES TO AROUND 20 KT OVER THE WESTERN WATERS N 
OF THE ITCZ BY SAT MORNING...WHILE NNW WINDS GRADUALLY INCREASE 
TO NEAR 20 KT ACROSS N PORTIONS OF BAJA CALIFORNIA WATERS BY SUN 
AFTERNOON. 

A QUICKLY WEAKENING COLD FRONT HAS MOVED INTO THE FAR NW CORNER 
OF THE DISCUSSION AREA...AND EXTENDED FROM 30N137.5W TO 
28.5N140W. THIS FRONT WILL MAKE EASTWARD PROGRESS ALONG 29-30N 
OVER THE WEEKEND AS IT WEAKENS...REACHING FROM 30N131W TO 
27.5N140W BY SUNDAY EVENING...WHERE IT WILL DISSIPATE. NW SWELL 
GENERATED BEHIND A SECOND FRONT A BIT FARTHER NW WILL MOVE INTO 
THESE NW WATERS EARLY SUN AND RAISE SEA HEIGHTS TO 8-10 FT BY 
SUN MORNING. 

OVER THE EASTERN WATERS E OF 120W...THERE ARE NO ONGOING GAP 
WIND EVENTS THAT EXCEED 20 KT WINDS...WHILE SEAS ARE GENERALLY 6 
FT OR LESS. GLOBAL MODELS INDICATE THAT NO SIGNIFICANT GAP WIND  
EVENTS ARE EXPECTED TO DEVELOP THROUGH THE WEEKEND...WHILE THE 
GULF OF TEHUANTEPEC MAY BEGIN TO DRAIN NORTHERLY WINDS NEAR 20 
KT MONDAY NIGHT THROUGH TUE MORNING. AS MENTIONED YESTERDAY... 
THIS IS THE FIRST TIME IN SEVERAL WEEKS THAT THERE IS NO GAP 
WIND ACTIVITY. OBSERVING THE SST SIGNALS VIA SATELLITE 
IMAGERY...THE PREDOMINANCE OF GAP WINDS FROM THE PAST SEVERAL 
WEEKS IS VERY EVIDENT BY COLD PLUMES EXTENDING DOWNWIND OF THE 
GULFS OF TEHUANTEPEC...PAPAGAYO...AND PANAMA. 

$$
STRIPLING