[Tropical] Tropical Weather Discussion

[EMWIN Server]

AXNT20 KNHC 121157
TWDAT

TROPICAL WEATHER DISCUSSION
NWS NATIONAL HURRICANE CENTER MIAMI FL
805 AM EDT SUN JUN 12 2011

TROPICAL WEATHER DISCUSSION FOR NORTH AMERICA...CENTRAL
AMERICA...GULF OF MEXICO...CARIBBEAN SEA...NORTHERN SECTIONS
OF SOUTH AMERICA...AND ATLANTIC OCEAN TO THE AFRICAN COAST
FROM THE EQUATOR TO 32N. THE FOLLOWING INFORMATION IS BASED
ON SATELLITE IMAGERY...WEATHER OBSERVATIONS...RADAR...AND
METEOROLOGICAL ANALYSIS.

BASED ON 0600 UTC SURFACE ANALYSIS AND SATELLITE IMAGERY THROUGH
1115 UTC.

...TROPICAL WAVES...

TROPICAL WAVE IS ALONG 38W S OF 10N MOVING W AT 10 KT.  THIS
WAVE IS SUBTLE AND NOT WELL DEFINED IN THE OBSERVATIONS OR IN
THE TOTAL PRECIPITABLE WATER IMAGERY.  THE WAVE...HOWEVER...CAN
BE IDENTIFIED IN THE GFS AND ECMWF MODEL ANALYSES AND IT IS ALSO
ASSOCIATED WITH ENHANCED CONVECTION ALONG THE ITCZ. SCATTERED
MODERATE CONVECTION IS WITHIN 120 NM OF THE WAVE AXIS BETWEEN 4N
AND 8N.

TROPICAL WAVE EXTENDS FROM 16N46W TO 4N49W MOVING WNW 10-12 KT.
THE SYSTEM SHOWS A CLASSIC INVERTED-V STRUCTURE IN THE
SHORT-WAVE INFRARED IMAGERY.  THE TOTAL PRECIPITABLE WATER
IMAGERY ALSO INDICATES A WELL-DEFINED MAXIMUM OF MOISTURE ON THE
EASTERN FLANK OF THE WAVE AXIS.  NO SIGNIFICANT DEEP CONVECTION
IS ASSOCIATED WITH THIS TROPICAL WAVE AT THIS TIME.

TROPICAL WAVE IS ALONG 80W S OF 12N MOVING W AT 10 KT.  THIS
WAVE WAS NEWLY INTRODUCED BASED UPON PANAMA RAWINSONDE TIME
SERIES...SATELLITE HOVMOLLER DIAGRAMS...AND GFS-ECMWF MODEL
DIAGNOSTICS. SCATTERED MODERATE ISOLATED STRONG CONVECTION
WITHIN 240 NM W OF AXIS.

...ITCZ/MONSOON TROUGH...

THE MONSOON TROUGH EXTENDS FROM INLAND WEST AFRICA AT 16N00W TO
15N10W TO THE COAST AT 14N16W TO 6N21W. THE ITCZ THEN CONTINUES
FROM THERE TO 4N30W TO SOUTH AMERICA AT 7N58W.  A SEPARATE
MONSOON TROUGH EXTENDS FROM THE EAST COAST OF COSTA RICA AT
10N83W EASTWARD INTO THE SW CARIBBEAN AND INTO COLUMBIA AT
10N76W.  SCATTERED MODERATE CONVECTION IS WITHIN 120 NM N OF THE
ITCZ AXIS BETWEEN 30W AND 40W. SCATTERED MODERATE AND ISOLATED
STRONG CONVECTION IS WITHIN 120 NM OF THE MONSOON TROUGH AXIS
FROM COSTA RICA TO 80W.

...DISCUSSION...

GULF OF MEXICO...
A 1015 MB HIGH IS CENTERED OVER THE N GULF OF MEXICO AT
29N88W...WHICH IS HELPING TO PRODUCE GENERALLY FAIR WEATHER WITH
LIGHT WINDS AND VERY LITTLE CLOUDINESS.  THE ONLY SIGNIFICANT
RAINFALL IS SOME SHOWERS AND THUNDERSTORMS JUST OFF OF THE COAST
OF WEST CENTRAL FLORIDA AND IN THE STRAITS OF FLORIDA.  THE
SHOWERS IN THE STRAITS OF FLORIDA ARE ASSOCIATED WITH A SURFACE
TROUGH THAT BEGINS NORTH OF THE BAHAMAS...GOES THROUGH THE
FLORIDA STRAITS...TO CUBA...AND OVER THE YUCATAN PENINSULA.  IN
THE UPPER LEVELS...NE TO SW ORIENTED TROUGHING IS SEEN ACROSS
THE GULF OF MEXICO AND STRONG SUBSIDENCE COVERS THE AREA.
LITTLE CHANGE IN THE THESE CONDITIONS ARE ANTICIPATED DURING THE
NEXT DAY.

CARIBBEAN SEA...
THE AFOREMENTIONED SURFACE TROUGH EXTENDS SOUTHWESTWARD TO THE
YUCATAN PENINSULA OF MEXICO AND GUATEMALA AT 17N91W.  DEEP
CONVECTION HAS DIMINISHED DURING THE EVENING...BUT SHOWERS
CONTINUE OVER THE YUCATAN...BELIZE...AND GUATEMALA.  AS
MENTIONED ABOVE...A MONSOON TROUGH EXTENDS INTO THE SW CARIBBEAN
AND IS ASSOCIATED WITH CONVECTION OVER COSTA RICA AND PANAMA.
SHOWERS ARE ALSO OCCURRING OVER WESTERN CUBA AS SEEN FROM THE
CASABLANCA RADAR IN ASSOCIATION WITH THE SURFACE TROUGH.
A MODERATE SURFACE PRESSURE GRADIENT IS PRODUCING EASTERLY WINDS
ACROSS THE CARIBBEAN OF GENERALLY 10 TO 20 KT...THOUGH NORTH OF
NE COLUMBIA THE TRADEWINDS REACH UP TO 25 KT.  IN THE UPPER
LEVELS...AN UPPER HIGH IS CENTERED OVER HISPANIOLA AND IS
PROMOTING GENERALLY FAIR WEATHER ACROSS MOST OF THE CARIBBEAN.
A SUBTROPICAL JET OF SW WINDS TO 50 KT OCCURS OVER THE NW
CARIBBEAN AND IS A RESULT OF THE UPPER HIGH AND THE UPPER TROUGH
OVER THE GULF OF MEXICO.  LITTLE CHANGE IN THE WINDS ARE
EXPECTED DURING THE NEXT DAY...WITH LIKELY LESS RAIN OVER CUBA
BUT CONTINUED RAINFALL OVER CENTRAL AMERICA.

ATLANTIC OCEAN...
A 1010 MB LOW IS CENTERED N OF THE BAHAMAS AT 27N78W. A SURFACE
TROUGH EXTENDS FROM 31N71W TO THE LOW CENTER TO THE STRAITS OF
FLORIDA AND CONTINUES TO THE CARIBBEAN.  DEEP CONVECTION HAS
CEASED OVER THE BAHAMAS THIS EVENING...BUT SHOWERS LIKELY HAVE
BEEN CONTINUING FOR THE NORTHERN AND CENTRAL BAHAMAS.  SCATTERED
MODERATE CONVECTION IS OCCURRING FROM 23N-28N BETWEEN 66W-71W. A
DISSIPATING COLD FRONT IS OVER THE CENTRAL ATLANTIC FROM 32N38W
TO 27N43W. ISOLATED MODERATE CONVECTION IS FROM 20N-24N BETWEEN
46W-55W IN ASSOCIATION WITH A WEAK 1013 MB SURFACE LOW AT 23N57W
WITH A TRAILING TROUGH TO ITS SOUTHWEST TO 18N60W AND ANOTHER
TROUGH TO ITS EAST TO 23N49W. A 1024 MB HIGH IS OVER THE E
ATLANTIC NEAR 31N26W PRODUCING FAIR WEATHER.  ALL OF THE
ATLANTIC OCEAN IN OUR AREA OF RESPONSIBILITY HAS WINDS 20 KT OR
LESS.  MOST OF THE REGION WILL SEE LITTLE CHANGE IN THE NEXT
DAY...THOUGH THE BAHAMAS WILL LIKELY HAVE LESS RAIN AS THE LOW N
OF THE BAHAMAS PULLS NORTHWARD AND WEAKENS.

F0R ADDITIONAL INFORMATION PLEASE VISIT
HTTP://WWW.HURRICANES.GOV/MARINE

$$
LANDSEA



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