000
AXPZ20 KNHC 300916
TWDEP 

TROPICAL WEATHER DISCUSSION 
NWS NATIONAL HURRICANE CENTER MIAMI FL
1005 UTC WED APR 30 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 0600 UTC SURFACE ANALYSIS AND SATELLITE IMAGERY THROUGH 
0830 UTC. 
  
...INTERTROPICAL CONVERGENCE ZONE/MONSOON TROUGH...
 
MONSOON TROUGH EXTENDS FROM COLOMBIA NEAR 09N75W TO 11.5N87W TO 
09N102W TO 08N118W...WHERE IT TRANSITIONS TO ITCZ...CONTINUING 
ON TO 06N130W TO BEYOND 07N140W. SCATTERED MODERATE TO STRONG 
CONVECTION NOTED WITHIN 300 NM S OF TROUGH BETWEEN 81W AND 98W. 
SCATTERED MODERATE TO STRONG CONVECTION NOTED WITHIN 90 NM N AND 
240 NM S OF TROUGH BETWEEN 111W AND 118W. SCATTERED MODERATE TO 
STRONG CONVECTION NOTED WITHIN 120 NM N AND 90 NM S OF ITCZ 
BETWEEN 118W AND 130W. 

...DISCUSSION...                                       

THE UPPER LEVEL BLOCKING PATTERN OF THE PAST FEW DAYS CONTINUES 
TO SLOWLY BREAK DOWN THIS MORNING AS A LARGE DEEP LAYERED TROUGH 
EXTENDING FROM THE GULF OF ALASKA TO NEAR 20N145W CONTINUES TO 
NUDGE THE UPPER PATTERN ACROSS THE DISCUSSION AREA EASTWARD. E 
OF THIS TROUGH A HIGH AMPLITUDE UPPER RIDGE EXTENDED FROM AN 
ANTICYCLONE NEAR 30N123W NORTHWARD ALONG THE W COAST OF N 
AMERICA...AND CONTINUED TO BE SANDWICHED BETWEEN THE UPPER 
TROUGH AND A PERSISTENT BROAD UPPER CYCLONE ACROSS THE CENTRAL 
U.S. DUE S OF THE ANTICYCLONE LIES A SLOWLY WEAKENING MIDDLE TO 
UPPER LEVEL CUT OFF CYCLONE NEAR 22N122W WITH MIDDLE LEVEL 
TROUGH EXTENDING SW TO 15N126W. AN ASSOCIATED UPPER LEVEL TROUGH 
HAS SHIFTED E DURING THE PAST 24 HOURS AND LEFT THE CYCLONE 
BEHIND...WITH THIS TROUGH WEAKENING AND SETTLING INTO A 
WEAKNESS ALONG 107-109W AND S OF 20N...BETWEEN TWO EQUATORIAL 
RIDGES ON EITHER SIDE. THE CYCLONE CONTINUED TO GENERATE 
ISOLATED CONVECTION ALOFT WITHIN 400 NM ACROSS THE E AND SE 
QUADRANTS... THROUGH 0600 UTC...BUT HAS SINCE DIMINISHED. THE 
EQUATORIAL RIDGES PERSIST BETWEEN FROM 04N TO 24N...BETWEEN 80W 
AND 103W...AND BETWEEN 115W AND 145W. THE LARGE DEEP LAYERED 
TROUGH TO THE W OF THE AREA WILL SWEEP NE AND FINALLY PUSH THE 
CUT OFF CYCLONE EASTWARD ACROSS THE S TIP OF BAJA CALIFORNIA AND 
INTO CENTRAL MEXICO DURING THE NEXT 24-36 HOURS. UNSTABLE MIDDLE 
TO UPPER LEVEL CONDITIONS ARE EXPECTED E AND SE OF THE CYCLONE 
AS IT SHIFTS INLAND DURING THIS TIME...AND IS EXPECTED TO LEAD TO 
ACTIVE CONVECTION ACROSS MUCH OF MEXICO S OF 22N BEGINNING THU. 
 
AT THE SURFACE...A COLLAPSING 1021 MB HIGH WAS CENTERED NEAR 
37N130W WITH WEAK RIDGE EXTENDING S INTO THE AREA W OF 120W. DUE 
TO THE WEAKENING HIGH AND ASSOCIATED RIDGE...THE PRESSURE 
GRADIENT HAS RELAXED THERE N OF THE ITCZ...AND NE TRADEWINDS 
HAVE DIMINISHED TO AROUND 15 KT...WITH ISOLATED POCKETS 15-20 
KT. IN TURN SEAS HAVE DIMINISHED TO AROUND 8 FT FROM 10N TO 14N 
W OF 131W. A COLD FRONT SUPPORTED BY THE DEEP LAYERED CENTRAL 
PACIFIC TROUGH EXTENDED FROM 32N140W THROUGH THE HAWAIIAN 
ISLANDS...AND WILL ENTER THE NW PORTION OF THE DISCUSSION AREA 
TODAY ACCOMPANIED BY A SW-W-NW WIND SHIFT AT 15-20 KT ACROSS THE 
WATERS FROM 28-32N WITH SEAS OF 7-9 FT. THE FRONT WILL SLOW AND 
WASH OUT ALONG 32N133W TO 23N140W ON THU.

GULF OF CALIFORNIA...A 1037 MB HIGH ACROSS THE GREAT BASIN 
REGION EXTENDS A RIDGE S INTO THE DESERT SW REGION OF THE U.S. 
AND HAS INDUCED A TIGHT PRESSURE GRADIENT ACROSS N PORTIONS OF 
THE GULF OF CALIFORNIA. NW WINDS THERE HAVE INCREASED TO 20-30 
KT TONIGHT ACROSS THE WATERS TO THE N OF 26N...AND WILL PERSIST 
THROUGH THIS AFTERNOON WITH SEAS BUILDING TO 11 FT IN AREAS OF 
LONG NW FETCH. THE GRADIENT WILL RELAX ON THU AFTERNOON WITH 
WINDS DIMINISHING TO LESS THAN 20 KT BY SUNRISE ON FRI. EXPECT 
FRESH TO STRONG NE WINDS TO BRIDGE INTO NORTHERN SEBASTIAN BAY 
TODAY THROUGH LATE THU.

GULF OF TEHUANTEPEC...THE NOCTURNAL NORTHERLY DRAINAGE WILL MAX 
AT 15 KT EARLY THIS MORNING...THEN INCREASE TO A 20 KT MAX ON 
TONIGHT AND THU NIGHT. GUIDANCE IS SUGGESTING A 20-25 KT EVENT 
ON FRI NIGHT THROUGH SUNRISE ON SAT...AND A 20-30 KT EVENT ON 
SAT NIGHT INTO SUNRISE ON SUN.

$$
STRIPLING