[Tropical] Tropical Weather Discussion

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AXNT20 KNHC 091204
TWDAT

TROPICAL WEATHER DISCUSSION
NWS NATIONAL HURRICANE CENTER MIAMI FL
805 AM EDT THU AUG 09 2012

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
1015 UTC.

...SPECIAL FEATURES...

TROPICAL STORM ERNESTO IS CENTERED NEAR 18.3N 94.0W AT 09/1200
UTC OR ABOUT 35 NM ENE OF COATZACOALCOS MEXICO MOVING WSW AT
11 KT. ESTIMATED MINIMUM CENTRAL PRESSURE IS 993 MB. MAXIMUM
SUSTAINED WIND SPEED IS 60 KT WITH GUSTS TO 75 KT. SCATTERED
MODERATE AND ISOLATED STRONG CONVECTION IS FROM 11N-22N BETWEEN
90W-98W. SEE LATEST NHC INTERMEDIATE PUBLIC ADVISORY UNDER
AWIPS/WMO HEADERS MIATCPAT5/WTNT35 KNHC AND THE FULL
FORECAST/ADVISORY UNDER AWIPS/WMO MIATCMAT5/WTNT25 KNHC FOR MORE
DETAILS.

TROPICAL WAVE EXTENDS FROM 10N41W TO 19N37W MOVING W AT 15 KT.
A 1010 MB LOW IS CENTERED ALONG THE WAVE AXIS NEAR 15N39W.
A MAXIMUM IN TOTAL PRECIPITABLE WATER IMAGERY IS ALSO OBSERVED
BETWEEN 34W-42W WITH SCATTERED MODERATE CONVECTION OCCURRING
SW OF THE LOW CENTER FROM 11N-15N BETWEEN 39W-42W. IT IS
POSSIBLE THAT A TROPICAL DEPRESSION MAY FORM DURING THE NEXT
COUPLE OF DAYS. THIS SYSTEM HAS A HIGH CHANCE OF BECOMING
A TROPICAL CYCLONE DURING THE NEXT 48 HOURS AS IT MOVES
WESTWARD 13 KNOTS.

...TROPICAL WAVES...

TROPICAL WAVE EXTENDS FROM 10N11W TO 18N12W MOVING W AT 15 KT.
THIS WAVE HAS BEEN TRACKED ACROSS AFRICA THE PAST FEW DAYS AND
EXHIBITS VERY DISTINCT CYCLONIC CIRCULATION IN THE LOW-LEVELS.
WHILE THIS CIRCULATION IS NOTED IN GLOBAL MODEL DATA BETWEEN
600-850 MB...THE ONLY APPARENT SURFACE CIRCULATION IS LOCATED ON
THE NORTHERN EXTENT OF THE WAVE AS A 1005 MB LOW CENTERED NEAR
16N12W ACCORDING TO RECENT SURFACE OBSERVATIONS ACROSS W AFRICA.
WHILE CONVECTIVE TRENDS IN THE VICINITY OF THE WAVE AXIS HAVE
BEEN DOWNWARD INTENSITY WISE THE PAST 6 HOURS...A COMPLEX OF
SCATTERED MODERATE CONVECTION IS FROM 08N-12N BETWEEN 13W-19W...
WITH SCATTERED SHOWERS ELSEWHERE ACROSS PORTIONS OF INLAND W
AFRICA FROM 10N-16N BETWEEN 10W-16W.

TROPICAL WAVE EXTENDS FROM 19N61W TO 26N57W MOVING W-NW AT 15
KT. THIS WAVE REMAINS THE REMNANTS OF WHAT WAS FLORENCE ACROSS
THE EASTERN ATLC EARLIER IN THE WEEK AND NOW IT INTERACTS WITH A
CENTRAL ATLC MIDDLE TO UPPER LEVEL TROUGH TO THE NORTH ALONG 26N
WHICH IS PROVIDING INCREASED UPPER LEVEL WIND SHEAR. SCATTERED
MODERATE CONVECTION IS FROM 20N-24N BETWEEN 57W-63W.

TROPICAL WAVE EXTENDS FROM 13N76W TO 22N74W MOVING W AT 15 KT.
CYCLONIC FLOW IS NOTED IN LOW-LEVEL GLOBAL MODEL STREAMLINE
ANALYSES ACROSS THE CENTRAL CARIBBEAN AND A MOISTURE MAXIMUM IS
NOTED ON TOTAL PRECIPITABLE WATER IMAGERY BETWEEN 69W-79W.
WIDELY SCATTERED MODERATE CONVECTION IS FROM 12N-19N BETWEEN
70W-78W. THIS CONVECTIVE ACTIVITY IS LIKELY ENHANCED DUE TO AN
UPPER LEVEL LOW CENTERED OVER JAMAICA NEAR 19N77W WHICH IS
PROVIDING MOIST SOUTHWESTERLY FLOW AND MAXIMUM DIFFLUENCE ALOFT.

...ITCZ/MONSOON TROUGH...

THE MONSOON TROUGH EXTENDS FROM THE AFRICAN COAST NEAR 12N17W TO
15N37W. THE INTERTROPICAL CONVERGENCE ZONE EXTENDS FROM 10N43W
TO 06N57W. SCATTERED MODERATE CONVECTION IS FROM 09N-11N BETWEEN
43W-48W.

...DISCUSSION...

GULF OF MEXICO...
UPPER LEVEL RIDGING IS NOTED ON WATER VAPOR IMAGERY OVER MUCH OF
THE GULF BASIN THIS MORNING WHICH IS LOCATED NORTH OF TROPICAL
STORM ERNESTO AS IT TRACKS ACROSS THE SW GULF WATERS. THE UPPER
LEVEL RIDGE IS CENTERED NEAR 24N94W. AT THE SURFACE...THE
PRESENCE OF ERNESTO IS PROVIDING MOSTLY CYCLONIC WINDS S OF 23N
BETWEEN 90W-97W. N OF 23N...A WEAK SURFACE RIDGE WITH AXIS ALONG
28N EXTENDS FROM THE SW NORTH ATLC ACROSS THE FLORIDA PENINSULA
INTO THE NW GULF NEAR 27N96W. MOSTLY CLEAR SKIES RESULT IN
ASSOCIATION WITH THE SURFACE RIDGE AND ONLY A FEW ISOLATED
SHOWERS AND TSTMS ARE OCCURRING ALONG THE NORTHERN GULF COAST N
OF 29N. MUCH OF THIS CURRENT WEATHER PATTERN IS EXPECTED TO
CHANGE VERY LITTLE THROUGH SATURDAY AS ERNESTO IS FORECAST TO
TRACK WESTWARD OVER THE SW GULF AND THEN WEAKEN AS IT MAKES
LANDFALL ACROSS MEXICO AND THE SURFACE RIDGE WILL REMAIN ALONG
28N OVER THE NORTHERN GULF WATERS.

CARIBBEAN SEA...
AN UPPER LEVEL LOW IS CENTERED OVER JAMAICA NEAR 19N77W AND IS
CONTINUING TO PULL A PORTION OF MIDDLE TO UPPER LEVEL OUTFLOW
MOISTURE FROM ERNESTO TO THE SOUTHEAST IN A TRAJECTORY ALONG
19N87W TO 13N80W TO 17N72W. THIS MOISTURE...WHILE NOT PRODUCING
ANY SIGNIFICANT DEEP CONVECTION ON THE WESTERN PERIPHERY OF THE
UPPER LEVEL LOW IS GENERATING SCATTERED SHOWERS OVER PORTIONS OF
THE WESTERN CARIBBEAN W OF 80W...INCLUDING PORTIONS OF CENTRAL
AMERICA. A FEW ISOLATED TSTMS ARE NOTED IN THE SW CARIBBEAN S OF
13N W OF 76W AS THE TROPICAL WAVE ALONG 76W APPROACHES.
OTHERWISE...THE UPPER LEVEL LOW...ALONG WITH THE LOW-LEVEL
FORCING OF THE TROPICAL WAVE IS CONTINUING TO GENERATE SCATTERED
SHOWERS AND TSTMS ACROSS THE CENTRAL CARIBBEAN THIS MORNING. AT
TIMES...LOCALLY HEAVY RAINFALL IS EXPECTED ACROSS PORTIONS OF
HISPANIOLA...JAMAICA...AND EASTERN CUBA DURING THE NEXT 24 TO 36
HOURS WITH THE HIGH POSSIBILITY OF LOCALIZED FLOODING AND THE
POTENTIAL FOR MUDSLIDES OVER THE HIGHER TERRAIN.

ATLANTIC OCEAN...
AN UPPER LEVEL ANTICYCLONIC CIRCULATION IS CENTERED NEAR 33N66W
AND CONTINUES TO SUPPORT A SURFACE RIDGE ACROSS NORTHERN
PORTIONS OF THE SW NORTH ATLC. THE RIDGE AXIS EXTENDS FROM
30N60W TO THE CENTRAL FLORIDA PENINSULA NEAR 28N81W. A FEW
ISOLATED SHOWERS AND TSTMS ARE OCCURRING ON THE NORTHWEST
PERIPHERY OF THE SURFACE RIDGE OFF THE COAST OF THE CAROLINAS
FROM 31N-34N BETWEEN 75W-79W. THE REMAINDER OF THE SW NORTH ATLC
S OF 26N IS UNDER THE INFLUENCE OF AN UPPER LEVEL LOW CENTERED
NEAR 19N77W THAT CONTINUES TO ADVECT MIDDLE TO UPPER LEVEL
MOISTURE NORTHWARD OVER THE TURKS AND CAICOS ISLANDS AS WELL AS
THE BAHAMAS. WIDELY SCATTERED SHOWERS ARE OCCURRING FROM 18N-26N
BETWEEN 66W-78W. FARTHER EAST...THE TROPICAL WAVE ALONG 59W...
MENTIONED ABOVE...REMAINS THE ONLY ACTIVE AREA CONVECTIVELY
OUTSIDE OF THE BROAD SURFACE RIDGING THAT ENCOMPASSES MOST OF
THE EASTERN AND CENTRAL ATLC. THE RIDGE IS ANCHORED BY A
STATIONARY 1024 MB HIGH CENTERED NEAR 33N48W.

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

$$
HUFFMAN




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