000
AXPZ20 KNHC 202148
TWDEP 

TROPICAL WEATHER DISCUSSION 
NWS NATIONAL HURRICANE CENTER MIAMI FL                         
2205 UTC FRI FEB 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 1800 UTC SURFACE ANALYSIS AND SATELLITE IMAGERY THROUGH 
2100 UTC. 
  
...SPECIAL FEATURES...

GULF OF PAPAGAYO GALE WARNING...A TIGHT PRES GRADIENT BETWEEN 
HIGH PRES RIDGING OVER CENTRAL AMERICA AND A SEGMENT OF THE 
MONSOON TROUGH ACROSS THE EPAC WATERS IS RESULTING IN NE 20-25 
KT WINDS WITHIN 60 NM EITHER SIDE OF LINE FROM 10N86W TO 09N89W 
TO 08N91W...INCLUDING THE GULF OF PAPAGAYO..WITH SEAS TO 8 FT. 
THESE WINDS ARE FORECAST TO INCREASE TO 20-30 LATE TONIGHT WITH 
30-35 KT WINDS WITHIN ABOUT 45 NM OF THE COAST OF THE GULF WITH 
SEAS OF 8-10 FT. BY EARLY SAT...THE NE WINDS WILL STILL RANGE IN 
THE 20-30 KT WITH THE 30-35 KT NEAR THE COAST. HOWEVER...BY 
EARLY SAT EVENING WITH THE WEAKENING OF THE GRADIENT...THE WINDS 
WILL RESPOND BY DIMINISHING FURTHER TO 20 KT OR LESS WITH SEAS 8 
FT IN MIXED NE...SW AND NW SWELL. ON EARLY SUN...A SLIGHT SURGE 
IN HIGH PRES ALONG WITH OVERNIGHT DRAINAGE FLOW MAY BE 
SUFFICIENT TO BRING NE 20-25 KT WITHIN 30 NM OF LINE FROM 11N86W 
TO 10N87W...INCLUDING THE GULF OF PAPAGAYO WITH SEAS TO 8 FT.
                   
...INTERTROPICAL CONVERGENCE ZONE/MONSOON TROUGH...
              
THE MONSOON TROUGH EXTENDS FROM 09N84 TO WEAK LOW PRES AT 05N89W 
1010 MB TO 04N92W. THE ITCZ CONTINUES FROM 04N92W TO 03N110W TO 
04N120W TO 05N130W TO 05N140W. NO SIGNIFICANT CONVECTION.

...DISCUSSION... 

A CUT-OFF MID TO UPPER LOW LIFTING NE IS LOCATED NEAR 19N133W  
WITH A TROUGH EXTENDING SOUTH TO NEAR 08N133W. THIS CUT-OFF LOW 
REMAINS AT THE SOUTHERN END OF A LARGE NARROW UPPER TROUGH THAT 
EXTENDS FROM CENTRAL CALIFORNIA SW TO 30N129W AND S TO THE 
AFOREMENTIONED LOW. VISIBLE SATELLITE IMAGERY REVEALS A SWIRL OF 
LOW CLOUDS IN ASSOCIATION WITH THIS LOW. A SURFACE TROUGH 
REFLECTION OF THIS UPPER-LEVEL FEATURE IS ANALYZED FROM 21N132W 
TO 15N132W. UPPER LEVEL DIVERGENCE TO THE E OF THE LOW/TROUGH IS 
HELPING TO INDUCE SOME CLUSTERS OF SCATTERED MODERATE/ISOLATED 
STRONG CONVECTION WITHIN 150 NM OF A LINE FROM 11N122W TO 
06N126W...AND FROM 14N TO 19N BETWEEN 122W AND 126W. THE CUT-OFF 
LOW IS FORECAST TO MOVE NE OVER THE NEXT 48 HOURS WHILE 
GRADUALLY WEAKENING. THE SURFACE TROUGH WILL DRIFT WESTWARD OVER 
THE NEXT 48 HOURS.

MODEL GUIDANCE IS SHOWING THAT THE NEXT COLD FRONT TO APPROACH 
THE NW PORTION OF THE REGION WILL BE AROUND EARLY SAT EVENING. 
WAVEWATCH GUIDANCE INDICATES THAT SEAS TO 9 FT IN NW SWELLS WILL 
OCCUR W OF OF A LINE FROM FROM 30N138W TO 23N140W BY SAT 
AFTERNOON. BY EARLY SUN...THE COLD FRONT IS FORECAST TO BE 
WEAKENING FROM 30N138W TO 26N140W. WINDS OF 20 KT OR LESS ARE 
FORECAST W OF A LINE FROM 30N131W TO 20N136W TO 14N140W WITH 
SEAS OF 8-10 FT IN NW SWELLS BY SUN AFTERNOON.
 
ALSO AT THE SURFACE...A 1028 HIGH CENTER WELL N OF THE AREA 
EXTENDS A RIDGE SE  ACROSS THE FORECAST WATERS TO NEAR 18N110W. 
THE HIGH IS FORECAST TO REMAIN NEARLY STATIONARY DURING THE NEXT 
24 HOURS. 

GAP WINDS...
GULF OF TEHUANTEPEC...THE TIGHT PRES GRADIENT OF THE PAST FEW 
DAYS IS WEAKENING AND THE MOST RECENT SCATTEROMETER PASS ONLY 
SHOWS NORTHERLY WINDS OF 20-25 KT ACROSS THIS GULF. BY EARLY 
THIS EVENING THESE WINDS ARE FORECAST TO DIMINISH TO 20 KT OR 
LESS WITH SEAS OF 8 FT IN MIXED NE AND NW SWELL. THIS SEAS WILL 
BE SLOW IN SUBSIDING AS INDICATED BY WAVEWATCH GUIDANCE BY EARLY 
SUN. MIXED NE AND SW SWELLS ARE EXPECTED TO RESULT IN 8 FT SEAS 
OVER AN AREA FROM 04N TO 08N BETWEEN 94W AND 100W BY SUN.     
                                              
GULF OF PANAMA...FRESH TO STRONG NORTHERLY WINDS ARE EXPECTED 
ACROSS THE GULF BY LATE TONIGHT AND EARLY FRI MORNING BEFORE 
DIMINISHING TO 20 KT OR LESS LATER DURING THE MORNING. THESE 
WINDS WILL MATERIALIZE AGAIN LATE SAT NIGHT AS HIGH OVER THE NW 
CARIBBEAN TIGHTENS THE PRES GRADIENT OVER THE SW CARIBBEAN SEA.

GULF OF CALIFORNIA...MODEL OUTPUT SUGGESTS THAT SW WINDS WILL 
INCREASE TO 20-25 KT OVER THE FAR NORTHERN SECTOR LATE SAT NIGHT 
INTO SAT AS LOW PRES FORMS OVER THAT PART OF THE GULF.

$$
GR