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AXPZ20 KNHC 231533
TWDEP

TROPICAL WEATHER DISCUSSION
NWS NATIONAL HURRICANE CENTER MIAMI FL
1605 UTC WED APR 23 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...

THE MONSOON TROUGH IS ILL-DEFINED. THE ITCZ AXIS EXTENDS FROM 04N95W TO 04N110W TO 06N125W TO 04N140W. SCATTERED MODERATE TO ISOLATED STRONG CONVECTION IS NOTED FROM 06N TO 10N BETWEEN 116W AND 120W...FROM 04N TO 10N BETWEEN 120W AND 130W AND FROM 02N TO 04N BETWEEN 132W AND 135W.


...DISCUSSION...

ALOFT...AN UPPER LEVEL TROUGH EXTENDS FROM 31N112W TO 21N124W. THIS TROUGH SUPPORTS A COLD FRONT THAT EXTENDS FROM 31N114W TO 28N118W. FRESH TO STRONG WINDS FOLLOW THE FRONT WITH SEAS TO 11 FT IN NW SWELL. NO SIGNIFICANT WEATHER IS ASSOCIATED WITH THE FRONT WHICH IS FORECAST TO DISSIPATE ACROSS THE FAR NE WATERS LATER TODAY. AN UPPER LEVEL RIDGE IS W OF THE TROUGH WITH AXIS NEAR 140W AND DOMINATES THE NW PART OF THE FORECAST AREA... MAINLY N OF 20N W OF 130W. A BROAD UPPER LEVEL RIDGE IS E OF THE TROUGH ACROSS NORTHERN MEXICO. MODERATE TO STRONG MID TO UPPER LEVEL SUBSIDENCE AND IMPLIED DRY AIR MASS IS NOTED ON WATER VAPOR IMAGERY N OF 16N W OF 130W AND ALONG THE TROUGH AXIS. IN THE DEEP TROPICS...AN UPPER LEVEL ANTICYCLONIC CIRCULATION IS CENTERED NEAR 9N127W. UPPER DIFFLUENT ASSOCIATED WITH THIS SYSTEM IS HELPING TO INDUCE THE CONVECTIVE ACTIVITY BETWEEN 116W AND 128W. A SHORT-WAVE TROUGH IS ACROSS THE ISTHMUS OF TEHUANTEPEC TO NEAR 12N85W. A RIDGE FROM NORTHERN SOUTH AMERICA EXTENDS WESTWARD COVERING MOST OF CENTRAL AMERICA.

A 1028 MB HIGH PRES LOCATED NEAR 32N142W EXTENDS A RIDGE SE ACROSS THE FORECAST WATERS TO NEAR 20N115W. FRESH TO STRONG NE TO E TRADE WINDS ARE NOTED PER SCATTEROMETER DATA ON THE SOUTHERN PERIPHERY OF THE RIDGE AND N OF THE ITCZ AXIS... PARTICULARLY FROM 10N TO 20N W OF 130W AND FROM 11N TO 17N BETWEEN 124W AND 130W. THE AERIAL EXTENT AND STRENGTH OF THE TRADES WILL DECREASE ON THU AS HIGH PRES MOVES EASTWARD AND DISSIPATES. WINDS OF 20-25 KT ARE ALSO NOTED JUST OFF OF NORTHERN BAJA CALIFORNIA DUE A TIGHT PRES GRADIENT BETWEEN A LOW CENTER OVER ARIZONA AND THE HIGH PRES. THESE WINDS ARE EXPECTED TO DIMINISH TO 20 KT OR LESS IN ABOUT 24 HOURS.

LONG PERIOD NW SWELLS...WITH A LEADING EDGE PERIOD OF 17-18 SECONDS WILL MIX WITH SHORTER PERIOD NE SWELL FROM THE TRADE WIND FLOW AND CROSS EQUATORIAL S SWELL TO GENERATE A LARGE AREA OF 8 TO 10 FT SEAS AFFECTING MAINLY THE WATERS E OF 130W AND S OF LINE FROM 13N130W TO 10N110W TO 3.4S90W BY THU MORNING...AND E OF 125W AND S OF LINE FROM 15N125W TO 17N110W TO 05N92W BY FRI MORNING. EXPECT ALSO BUILDING SEAS TO 8 FT E OF THE GALAPAGOS ISLANDS TO ABOUT 2N. BASED ON WAVE WATCH GUIDANCE...THIS SWELL EVENT IS FORECAST TO REACH THE MEXICAN COAST E OF 110W THU NIGHT...AND THE SOUTH PORTION OF THE GULF OF CALIFORNIA OR SEA OF CORTEZ EARLY ON FRI...BRINGING ROUGH SURF CONDITIONS TO THOSE COAST.

WINDS ARE EXPECTED TO PULSE TO 15-20 KT ACROSS THE GULF OF PAPAGAYO DURING THE OVERNIGHT AND EARLY MORNING HOURS WITH THE ASSISTANCE OF THE NOCTURNAL DRAINAGE FLOW THROUGH THE FORECAST PERIOD.

$$ GR

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