Eastern Pacific Tropical Weather Discussion

000
AXPZ20 KNHC 191617
TWDEP 

TROPICAL WEATHER DISCUSSION
NWS NATIONAL HURRICANE CENTER MIAMI FL
1605 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 1200 UTC SURFACE ANALYSIS AND SATELLITE IMAGERY THROUGH 
1500 UTC. 

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

MONSOONAL CIRCULATION NOT YET ESTABLISHED ACROSS THE REGION. 
ITCZ EXTENDS FROM 06N86W AND MEANDERS WESTWARD TO 06.5N99W TO 
05.5N112W TO 05N126W TO BEYOND 03.5N140W. SCATTERED MODERATE TO 
STRONG CONVECTION NOTED FROM 02.5N TO 07N E OF 82W. ISOLATED TO 
SCATTERED MODERATE TO STRONG CONVECTION NOTED WITHIN 150 NM N 
AND 120 NM S OF ITCZ AXIS W OF 86W. 

...DISCUSSION...                                                

A MID TO UPPER LEVEL CYCLONE OVER THE DESERT SW OF THE U.S. 
CONTINUES TO SHIFT SLOWLY EASTWARD ACROSS THE REGION...WITH AN 
ASSOCIATED BROAD TROUGH AXIS EXTENDING SW TO A MIDDLE LEVEL 
CYCLONE NEAR 22N128W THEN ON TO 22N135W. E OF THIS FEATURE A 
RATHER FLAT UPPER RIDGE AXIS EXTENDED FROM NEAR 13N ALONG 96-97W 
NORTHWARD ACROSS MEXICO AND AMPLIFIED INTO THE CENTRAL U.S. 
OTHERWISE...UPPER FLOW S OF 15N REMAINS SOMEWHAT COMPLEX AS 
WESTERLIES GENERALLY PREVAIL ACROSS THE REGION. ACTIVE 
CONVECTION IN THE VICINITY HAS BEEN PERSISTENT IN RECENT DAYS 
AND IS SUFFICIENTLY DEEP INTO THE TROPOSPHERE TO INTERRUPT AND 
DIVERT THE UPPER FLOW...WITH A WEAK UPPER LEVEL ANTICYCLONE 
INDUCED ACROSS ACTIVE CONVECTION OCCURRING W OF 120W.

THE DEEP LAYERED CYCLONE MOVING ACROSS THE SW U.S. WILL AID IN 
PRODUCING BROAD AND ELONGATED LOW PRESSURE ACROSS MOST OF MEXICO 
TODAY...WHICH IN TURN WILL YIELD MODERATE W TO SW FLOW ACROSS 
THE GULF OF CALIFORNIA TODAY. OTHERWISE...A BROAD HIGH PRESSURE 
RIDGE PREVAILS ACROSS THE REGION...CENTERED ON A 1025 MB HIGH 
NEAR 29N143W EXTENDING SE TO NEAR 18N112W. A MODEST PRESSURE 
GRADIENT BETWEEN THE RIDGE AND LOWER PRES INVOF THE ITCZ IS 
YIELDING A ZONE OF NE TRADEWINDS AROUND 20 KT WITH ISOLATED 
POCKETS TO 25 KT FROM 07N TO 24N W OF 137W EXTENDING TO S OF THE 
HAWAIIAN ISLANDS. SEAS ACROSS THE AREA ARE RUNNING 8-10 FT IN 
MIXED NE AND NW SWELL. A COLD FRONT IS APPROACHING THE REGION 
JUST TO THE NW THIS MORNING AND WILL FORCE THIS SURFACE HIGH TO 
THE E DURING THE NEXT FEW DAYS...AND DIMINISH SLIGHTLY THE 
PRESSURE GRADIENT AND TRADE WINDS THROUGH SUN. 

GALE FORCE NORTHERLY WINDS BLOWING THROUGH AND DOWNSTREAM OF THE 
GULF OF TEHUATEPEC HAVE DIMINISHED TO 30 KT THIS MORNING...AS 
HIGH PRES ACROSS THE GULF OF MEXICO IS SHIFTING NORTHEASTWARD. 
WINDS THROUGH TEHUANTEPEC WILL DIMINISH A BIT MORE TO 20-25 KT 
THIS AFTERNOON...THEN INCREASE TO 30 KT TONIGHT...AS NOCTURNAL 
DRAINAGE ENHANCES THE N WINDS. NORTHERLY WINDS ARE THEN EXPECTED 
TO END BY SUNDAY AFTERNOON THERE...WITH WINDS AND SEAS QUICKLY 
DIMINISHING. 

LOOK FOR AREAS OF ACTIVE CONVECTION TO CONTINUE TO PULSE NEAR 
THE ITCZ DURING THE NEXT FEW DAYS AS AMPLE MOISTURE AND 
INSTABILITY PREVAIL.

$$
STRIPLING