Eastern Pacific Tropical Weather Discussion

000
AXPZ20 KNHC 190230
TWDEP 

TROPICAL WEATHER DISCUSSION
NWS NATIONAL HURRICANE CENTER MIAMI FL
0405 UTC SAT APR 19 2014

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 0000 UTC SURFACE ANALYSIS AND SATELLITE IMAGERY THROUGH 
0215 UTC. 

...SPECIAL FEATURE...

GALE WARNING FOR THE GULF OF TEHUANTEPEC... 

A SURFACE LOW OVER THE NE GULF OF MEXICO HAS DRAGGED A COLD 
FRONT THROUGH THE S-CENTRAL GULF OF MEXICO. NORTHERLY FLOW HAS 
INCREASED ACROSS THE WESTERN GULF OF MEXICO IN THE WAKE OF THIS 
FRONT WITH NORTHERLY 20-25 KT WINDS CURRENTLY SURGING INTO THE 
GULF OF TEHUANTEPEC. THE GRADIENT WILL FURTHER TIGHTEN TONIGHT 
WITH MINIMAL GALE CONDITIONS EXPECTED FROM MIDNIGHT THROUGH 
SUNRISE ON SAT. WINDS WILL QUICKLY DIMINISH THROUGHOUT THE DAY 
ON SAT WITH ONLY N-NE 20-25 KT WINDS EXPECTED ON SAT EVENING 
THROUGH SUNRISE ON SUN. THE NOCTURNAL MAXIMUM DRAINAGE SHOULD 
ONLY MAX 15-20 KT EACH NIGHT FROM SUN NIGHT THROUGH WED NIGHT. 

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

THE EPAC MONSOON TROUGH EXTENDS SW FROM THE COAST OF PANAMA AT 
08N82W TO 07N91W WHERE SCATTEROMETER WINDS INDICATE A TRANSITION 
TO AN ITCZ AXIS...WHICH CONTINUES SW TO 04N110W...THEN NW TO 
06N122W....THEN W TO BEYOND 06N140W. 

SCATTERED MODERATE ISOLATED STRONG CONVECTION IS NOTED ALONG THE
MONSOON TROUGH AND ITCZ AXIS WITHIN 150 NM EITHER SIDE OF LINES 
FROM 07N80W TO 04N104W AND FROM 08N118W TO 04N138W.

A PERSISTENT MID-UPPER TROUGH HAS A SURFACE REFLECTION EXTENDING
FROM 14N109W TO 03N111W. SCATTERED MODERATE ISOLATED STRONG 
CONVECTION IS FLARING WITHIN 75 NM OF 13.5N108.5W. ISOLATED
MODERATE TO STRONG CONVECTION IS OBSERVED WITH 60 NM EITHER SIDE
OF A LINE FROM 09N108W TO 03N110W.

...DISCUSSION...                                                

AN UPPER CYCLONE IS OVER EXTREME SOUTHERN CALIFORNIA WITH A MID 
TO UPPER TROUGH EXTENDING SW TO A BASE NEAR 17N131W. DENSE UPPER 
DEBRIS IS CONCENTRATED E OF THE TROUGH AXIS AND SPREADING NE 
ACROSS NORTHERN MEXICO...WITH SOME OF THE MOISTURE ALSO 
SPREADING N ACROSS SOUTHERN CALIFORNIA...ARIZONA...NEW MEXICO 
AND W TEXAS. SOME OF THIS MOISTURE IS JUST NOW SPREADING E 
ACROSS THE WESTERN GULF OF MEXICO.        

AN UPPER LEVEL ANTICYCLONE IS QUASI-STATIONARY JUST W OF THE 
AREA AT 08N141W WITH A RIDGE EXTENDING E ACROSS THE TROPICS TO A 
CREST NEAR 05N114W. UPPER DIFFLUENCE UNDER THIS RIDGE CONTINUES 
TO ENHANCE CONVECTION ALONG THE ITCZ TO THE W OF 115W.

THE PREVIOUSLY DESCRIBED SURFACE TROUGH FROM 14N109W TO 03N111W 
IS UNDER AN UPPER TROUGH THAT IS QUASI-STATIONARY FROM 03-15N 
BETWEEN 103-113W. THIS UPPER TROUGH SEPARATES THE ANTICYCLONIC 
FLOW JUST DESCRIBED OVER THE SW PORTION FROM ANOTHER TROPICAL 
ANTICYCLONE OVER THE SE PORTION ASSOCIATED WITH AN UPPER RIDGE 
EXTENDING W OFF THE COAST OF COLOMBIA ALONG 07N TO THE E OF 
100W. THIS UPPER RIDGE IS IN PHASE WITH THE LOWER LEVER MONSOON 
TROUGH AND ITCZ...AND IS SUPPORTING THE PREVIOUSLY DESCRIBED 
CONVECTION. SOME OF THE RESULTANT DEBRIS MOISTURE IS ADVECTED NE 
ACROSS CENTRAL AMERICA...THEN THINS AS IT TURNS E-NE ACROSS THE 
CENTRAL CARIBBEAN.

A SURFACE HIGH PRESSURE RIDGE EXTENDS FROM 29N140W TO NEAR 
18N105W. NE TRADES ARE ENHANCED TO 15-20 KT BETWEEN THE RIDGE 
AND 07N TO THE W OF 120W...WITH SEAS OF 6-8 FT IN MIXED LONG 
PERIOD NW AND NE SWELL WITH ADDITIONAL LONG PERIOD CROSS-
EQUATORIAL SE SWELL. THIS AFFECTED AREA S OF THE RIDGE WILL 
PERSIST THROUGH THE WEEKEND. NW TO N 15 KT WINDS WILL CONTINUE 
THROUGH THE WEEKEND TO THE NE OF THE RIDGE TO THE PACIFIC COAST
OF THE BAJA CALIFORNIA PENINSULA WITH SEAS OF 4-5 FT. A NEW 
BATCH OF NW SWELL WILL ARRIVE AT 30N140W SAT NIGHT...AND CONTINUE
TO PROPAGATE E REACHING THE NW COAST OF THE BAJA PENINSULA IN THE 
FORM COMBINED SEAS OF 6-9 FT ON MON. SEAS OF 8-9 FT IS EXPECTED 
ACROSS THE DISCUSSION WATERS N OF 20N BETWEEN 112W-135W ON TUE.

$$
NELSON