Tropical Weather Discussion
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000
AXPZ20 KNHC 270951
TWDEP

TROPICAL WEATHER DISCUSSION
NWS NATIONAL HURRICANE CENTER MIAMI FL
1005 UTC WED MAY 27 2015

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 0945 UTC.

...SPECIAL FEATURE...

A 1010 MB SURFACE LOW HAS FORMED FROM A TROPICAL WAVE NEAR
09.5N105.5W. SCATTERED MODERATE ISOLATED STRONG CONVECTION IS
OBSERVED WITHIN 330 NM OF 08N107.5W. ALTHOUGH THE ASSOCIATED
WINDS ARE CURRENTLY ONLY 10-15 KT NEAR THE CENTER...THE GRADIENT
IS SUPPORTING 15 KT SOUTHERLY FLOW WITHIN 540 NM OVER THE SE
QUADRANT OF THE LOW WHERE COMBINED SEAS ARE 7-8 FT PRIMARILY DUE
TO CROSS-EQUATORIAL SW SWELL. THE LOW IS FORECAST TO MOVE TO
NEAR 10N109W AND DEEPEN TO ABOUT 1007 MB TONIGHT AND REACH NEAR
12N112W ON THU NIGHT WITH AN ESTIMATED PRESSURE OF 1005 MB. BY
THEN CONDITIONS WILL BECOME FAVORABLE FOR TROPICAL CYCLONE
FORMATION AS THE LOW CONTINUES NW REACHING NEAR 13N113W ON FRI
NIGHT AND NEAR 14N113W ON SAT NIGHT.

...TROPICAL WAVES/LOWS...

A TROPICAL WAVE EXTENDS FROM 04-12N ALONG 94W AND HAS BEEN
PROGRESSING W AT 10-15 KT. SCATTERED MODERATE ISOLATED STRONG
CONVECTION IS OBSERVED WITHIN 150 NM OF 07N94.5W.

A 1010 MB SURFACE LOW PRESSURE IS ANALYZED NEAR 09N119W WITH
SCATTERED MODERATE ISOLATED STRONG CONVECTION NOTED NW OF THE
LOW WITHIN 75 NM EITHER SIDE OF A LINE FROM 14N115W TO 09N124W.
NE TRADES ARE ENHANCED TO 15-20 KT WITHIN 180 NM OVER THE NW
QUADRANT OF THE LOW WITH COMBINED SEAS OF 7-8 FT IN MIXING S AND
SW SWELL. THE LOW IS FORECAST TO MOVE TO NEAR 09N123W TONIGHT
AND NEAR 09N125W ON THU NIGHT. COMBINED SEAS OF 7-8 FT ARE THEN
EXPECTED WITHIN 390 NM OVER THE NW QUADRANT OF THE LOW.

A 1009 MB SURFACE LOW IS ANALYZED AT 12.5N131W WITH SCATTERED
MODERATE CONVECTION NOTED WITHIN 30 NM OF A LINE FROM 15N128W TO
09N134W. THE GRADIENT SHOULD SUPPORT NE 15-20 KT TRADES WITHIN
ABUT 300 NM NW OF THE LOW OVER THE NEXT FEW DAYS WITH COMBINED
SEAS OF 7-8 FT.

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

CURRENTLY THERE IS NOT A WELL DEFINED MONSOON TROUGH OR ITCZ.
SCATTERED MODERATE ISOLATED STRONG CONVECTION IS OBSERVED ALONG
THE COAST OF COLOMBIA WITHIN 75 NM OF 03N79W AND PARALLEL TO THE
PACIFIC COAST OF CENTRAL AMERICA WITHIN 45 NM EITHER SIDE OF A
LINE FROM 08N78W TO 08N88W...ALONG THE COAST OF MEXICO WITHIN 60
NM EITHER SIDE OF A LINE FROM 13.5N90W TO 16N96W...AND ACROSS
THE DEEP TROPICAL PACIFIC WITHIN 75 NM EITHER SIDE OF A LINE
FROM 06N119W TO 01N130W.

...DISCUSSION...

AN UPPER CYCLONE IS OBSERVED NW OF THE AREA NEAR 37N148W WITH
AN UPPER TROUGH EXTENDING S TO THE HAWAIIAN ISLANDS. AN
ASSOCIATED SURFACE FRONTAL TROUGH IS CURRENTLY DISSIPATING FROM
32N134W TO 28N133W TO 25N140W. ASSOCIATED SURFACE WINDS ARE 5-10
KT ACROSS THE DISCUSSION WATERS.

AN UPPER CYCLONE IS CENTERED AT 33N120W AND IS PROGRESSING NE
WITH TIME WHILE TRAILING AN UPPER TROUGH S TO BASE NEAR 23N119W.
UPPER DEBRIS MOISTURE SURROUNDS THE CYCLONE AND EXTENDS E ACROSS
SOUTHERN CALIFORNIA AND THE NORTHERN GULF OF CALIFORNIA.

UPPER ANTICYCLONES ARE CENTERED OVER THE TROPICS NEAR 14N121W
AND NEAR 13N102W WITH AN UPPER RIDGE EXTENDING WSW TO A CREST
NEAR 13N132W. THE ASSOCIATED UPPER DIFFLUENCE IS ENHANCING
CONVECTION ALONG THE TROPICAL LOWS AND TROPICAL WAVES AS
PREVIOUSLY DESCRIBED. ALTHOUGH MOST OF THE DEBRIS MOISTURE IS
ADVECTED S ACROSS THE EQUATOR BETWEEN 90-130W...SOME OF THE
DEBRIS MOISTURE CONCENTRATES INTO A NARROW TROPICAL PLUME
CROSSING THE SOUTHERN TIP OF THE BAJA CALIFORNIA PENINSULA. AN
UPPER RIDGE ALSO EXTENDS NW TO BEYOND 32N132W WITH UPPER
MOISTURE SPREADING E AND SE ACROSS THE RIDGE CREST INTO THE
DISCUSSION AREA NEAR 29N128W.

AN UPPER ANTICYCLONE OVER COLOMBIA RIDGES NW TO A CREST NEAR
PANAMA. AN UPPER TROUGH EXTENDS SW ACROSS THE WESTERN CARIBBEAN
TO BASE OVER NICARAGUA. THIS PATTERN SETS UP AN AREA OF UPPER
DIFFLUENCE AND IS ENHANCING CONVECTION AND THE DEEP TROPICS
BETWEEN 80-90W AS PREVIOUSLY DESCRIBED. SOME OF THE DEBRIS
MOISTURE IS ADVECTED NE ACROSS THE SOUTHERN CARIBBEAN.

GULF OF TEHUANTEPEC...EXPECT A BRIEF NORTHERLY SURGE TO 20-25
KT LATE TONIGHT WITH SEAS BUILDING BRIEFLY TO 8 FT AT SUNRISE
THU.

GULF OF PAPAGAYO...CURRENTLY ENE 20-25 KT WINDS SHOULD DIMINISH
AFTER SUNRISE THIS MORNING...THEN EXPECT ANOTHER BRIEF 20-25 KT
SURGE AGAIN TONIGHT..THEN ONLY 15-20 KT NOCTURNAL PULSES
FORECAST THE REMAINDER OF THE WEEK.

$$
NELSON



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