000
AXPZ20 KNHC 231622
TWDEP
TROPICAL WEATHER DISCUSSION
NWS NATIONAL HURRICANE CENTER MIAMI FL
1605 UTC THU MAY 23 2013
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
1430 UTC.
...INTERTROPICAL CONVERGENCE ZONE/MONSOON TROUGH...
MONSOON TROUGH AXIS EXTENDS FROM COLOMBIA NEAR 06.5N74.5W TO
13N87.5W TO LOW PRES NEAR 10.5N103W 1009 MB TO 08.5N118W...WHERE
IT TRANSITIONS TO ITCZ...CONTINUING ON TO 09N123W TO 11.5N133W
TO BEYOND 07N140W. SCATTERED MODERATE TO STRONG CONVECTION NOTED
WITHIN 180 NM S OF TROUGH BETWEEN 78W AND 86W...AND WITHIN 210
NM N AND 300 NM S OF TROUGH BETWEEN 90W AND 100W. SCATTERED TO
LOCALLY NUMEROUS MODERATE TO STRONG CONVECTION NOTED WITHIN 90
NM N AND 180 NM S OF TROUGH BETWEEN 102W AND 116W. SCATTERED
MODERATE TO STRONG CONVECTION NOTED WITHIN 90 NM S AND 180 NM N
OF ITCZ BETWEEN 129W AND 135W.
...DISCUSSION...
A GENERALLY RIDGE-TROUGH-RIDGE UPPER LEVEL PATTERN PREVAILS
ACROSS THE DISCUSSION AREA THIS MORNING. THE TWO RIDGES ARE S OF
22N-24N AND SPAN BETWEEN 120W AND 144W...AND BETWEEN 70W AND
126W RESPECTIVELY...AND CONTINUE TO VENTILATE DEEP TROPICAL
CONVECTION ALONG AND NEAR THE MONSOON TROF AND ITCZ DESCRIBED
ABOVE. A SHORTWAVE TROUGH HAS MOVED OVER THE WESTERN RIDGE AND
IS MOVING E-SE AND SLOWLY DIVING INTO THE BACK SIDE OF THE
TROUGH PREVAILING BETWEEN THE TWO RIDGES...BETWEEN 110W AND
120W...AND HAS ERODED MODESTLY W PORTIONS OF THE EASTERN-MOST
RIDGE. THE FORWARD PROGRESS OF THE MEAN UPPER TROUGH IS FORECAST
TO END TONIGHT WHILE THE TROUGH SHARPENS OVER THE WEEKEND...AS
THE TWO UPPER RIDGES AMPLIFY.
AT LOW LEVELS...EPAC SURFACE RIDGE DOMINATES THE AREA W OF
110W...CENTERED ON A 1033 MB HIGH NEAR 41N143W...WITH RIDGE AXIS
EXTENDING SE TO NEAR 18N112W. OVERNIGHT SCATTEROMETER PASSES
INDICATED MINIMAL N-NW GALES CONTINUING OFF THE CENTRAL
CALIFORNIA COAST...WITH FRESH N TO NE WINDS SPILLING S AND SW
INTO NORTH PORTIONS OF THE DISCUSSION AREA N OF 24N. NORTHERLY
SWELL GENERATED WITHIN THIS REGION OF WINDS CONTINUES TO
PROPAGATE S AND SE...AND WAS PRODUCING SEAS OF 8 TO 13 FT ACROSS
THE AREA N OF 24N...WITH HIGHEST SEAS WELL OFFSHORE OF BAJA
CALIFORNIA NORTE.
THE REMNANTS OF ALVIN WERE LOCATED ACROSS SW PORTIONS...
PROPAGATING WWD AS A LARGE AMPLITUDE WAVE ALONG THE ITCZ AT
133W. A MODEST REGION OF FRESH NE WINDS AROUND 20 KT CONTINUE N
OF THIS WAVE AND ARE PRODUCING SEAS 8-9 FT. THIS WAVE WILL
CONTINUE W AND EXIT THE AREA IN THE NEXT 36 HOURS. AS IT PASSES
DIRECTLY S OF THE EPAC HIGH...WINDS MAY INCREASE SLIGHTLY TO 20-
25 KT.
E OF 110W...MODERATE MONSOONAL FLOW DOMINATES THE TROPICS AND IS
PRODUCING CONVERGENCE OF ABUNDANT TROPICAL MOISTURE INVOF THE
MONSOON TROUGH. SATELLITE IMAGERY THE PAST 24 HOURS HAS REVEALED
A LOW TO MIDDLE LEVEL CYCLONIC CIRCULATION...AND SCATTERED TO
NUMEROUS CONVECTION...NOW CURRENTLY INVOF 10N104W. A 1009 MB
SURFACE LOW HAS DEVELOPED NEAR THERE NEAR 10.5N103W...WITH MOST
CONVECTION NOW FLARING TO THE S AND SW OF THIS LOW. GLOBAL
MODELS SUGGEST THERE IS SOME CHANCE FOR SLOW AND GRADUAL
ORGANIZATION OF THIS LOW AS IT MOVES WWD DURING THE NEXT SEVERAL
DAYS.
FARTHER E...LOW TO MIDDLE LEVEL CYCLONIC TURNING IS ALSO NOTED
CENTERED INVOF 08N87W. S TO SW MONSOONAL WINDS PREVAIL AT THE
SURFACE IN THIS LOCATION...BUT AS THIS FEATURE DRIFTS W OVER THE
WEEKEND IT IS EXPECTED TO BECOME BETTER ALIGNED WITH THE MONSOON
TROUGH. STRENGTHENING HIGH PRES ACROSS THE SW N ATLANTIC IS
EXPECTED TO ENHANCE THE TRADE WINDS ACROSS THE CENTRAL AND W
CARIBBEAN BY THE EARLY PART OF THE UPCOMING WEEK...WHICH WILL
INDUCE GAP WIND FLOW ACROSS CENTRAL AMERICA AND INTO THE EPAC.
THIS SCENARIO WILL CREATE FAVORABLE LOW TO MIDDLE TROPOSPHERIC
CONDITIONS FOR A WAVE TO DEVELOP AND GROW ACROSS THIS AREA AS IT
SHIFTS WWD AND DOWNSTREAM OF THE GULFS OF PAPAGAYO AND
TEHUANTEPEC. GLOBAL MODELS ARE PRESENTLY IN DISAGREEMENT IN THE
STRENGTH OF DEVELOPMENT OF THIS WAVE...WITH THE GFS MODEL
DEVELOPING A TROPICAL CYCLONE WITHIN THE NEXT 5 DAYS. THIS AREA
IS BEING MONITORED FOR THIS POTENTIAL DURING THE UPCOMING WEEK.
LONG PERIOD CROSS HEMISPHERIC SW SWELL AT 17-19 SECONDS IS
MOVING THROUGH THE AREA WATERS THIS MORNING AND HAVE BEGUN TO
INCREASE ALONG THE CENTRAL AMERICAN AND MEXICAN COASTS.
OVERNIGHT ALTIMETER PASSES INDICATED THAT WW3 MODEL GUIDANCE WAS
GENERALLY 1.5 TO 2 FT TOO LOW IN ITS FORECAST OF THIS SWELL.
EXPECTED SW SWELL AND ADDITIONAL PULSES TO DOMINATE THE AREA
WATERS THROUGH THE WEEKEND...AND PRODUCING STRONG AND DANGEROUS
SURF ACROSS THE COASTS AND REEFS OF THE AREA COASTLINES.
$$
STRIPLING
