[Tropical] Tropical Weather Discussion

[EMWIN Server]

AXNT20 KNHC 081743
TWDAT

TROPICAL WEATHER DISCUSSION
NWS NATIONAL HURRICANE CENTER MIAMI FL
205 PM EDT TUE SEP 08 2015

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 1200 UTC SURFACE ANALYSIS AND SATELLITE IMAGERY THROUGH
1730 UTC.

...SPECIAL FEATURES...

THE CENTER OF TROPICAL DEPRESSION GRACE AT 08/1500 UTC IS NEAR
14.3N 42.8W. GRACE IS MOVING TOWARD THE W...OR 275 DEGREES...17
KT. THE MINIMUM CENTRAL PRESSURE IS 1007 MB. THE MAXIMUM
SUSTAINED WIND SPEEDS ARE 30 KNOTS WITH GUSTS TO 40 KT.
SCATTERED MODERATE CONVECTION IS FROM 14N-16N BETWEEN 39W-42W.
PUBLIC ADVISORIES ABOUT TROPICAL DEPRESSION GRACE ARE BEING
ISSUED UNDER THE WMO HEADER WTNT32 KNHC...AND UNDER THE AWIPS
HEADER MIATCPAT2. FORECAST/ADVISORIES ARE BEING ISSUED UNDER THE
WMO HEADER WTNT22 KNHC...AND UNDER THE AWIPS HEADER MIATCMAT2.

A 1014 MB BROAD AREA OF LOW PRESSURE IS LOCATED AT ABOUT 300
MILES ESE OF BERMUDA NEAR 31N60W. SCATTERED MODERATE CONVECTION
IS OBSERVED FROM 29N-34N BETWEEN 56W-62W. ENVIRONMENTAL
CONDITIONS ARE EXPECTED TO BECOME FAVORABLE FOR DEVELOPMENT
DURING THE NEXT COUPLE OF DAYS WHILE THE SYSTEM REMAINS NEARLY
STATIONARY FOR AT LEAST 24 HOURS. AFTER THAT...THE SYSTEM WILL
MOVE N AT AROUND 10 KT. THIS LOW HAS A MEDIUM CHANCE OF
FORMATION OVER THE NEXT 48 HOURS.

...TROPICAL WAVES...

A TROPICAL WAVE IS MOVING ACROSS THE E ATLANTIC WITH AXIS
EXTENDING FROM 21N25W TO 08N25W...MOVING W AT 10 TO 15 KT. THIS
POSITION IS A MEAN POSITION THAT IS BASED ON SATELLITE IMAGERY
AND THE 700 MB WIND FIELD. SCATTERED MODERATE CONVECTION IS FROM
10N-16N BETWEEN 20W-28W.

A TROPICAL WAVE IS MOVING ACROSS THE CENTRAL ATLANTIC WITH AXIS
EXTENDING FROM 17N51W TO 08N52W...MOVING W AT 15 KNOTS. TPW
IMAGERY DEPICTS A HIGH MOISTURE CONTENT IN THE SOUTHERN PORTION
OF THIS WAVE S OF 13N WHERE SCATTERED MODERATE CONVECTION IS
OBSERVED FROM 07N-13N BETWEEN 49W-55W.

A TROPICAL WAVE IS MOVING ACROSS THE E CARIBBEAN WITH AXIS
EXTENDING FROM 18N64W TO 11N65W...MOVING W AT 15 KT. A LOW-LEVEL
CIRCULATION IS TRYING TO FORM ALONG THE SOUTHERN PORTION OF THE
WAVE SUPPORTING SCATTERED CONVECTION FROM 11N-15N BETWEEN 64W-
68W.

A TROPICAL WAVE IS MOVING ACROSS THE W CARIBBEAN WITH AXIS
EXTENDING FROM 20N79W TO 10N81W...MOVING W AT 10 TO 15 KNOTS.
TPW IMAGERY SHOWS THAT THIS WAVE IS IN A DRY ENVIRONMENT AND NO
CONVECTION IS OBSERVED AT THIS TIME.

...ITCZ/MONSOON TROUGH...

THE MONSOON TROUGH PASSES THROUGH THE COAST OF AFRICA REACHING
THE ATLANTIC OCEAN NEAR 19N16W AND EXTENDING TO 16N38W. ASIDE
FROM THE CONVECTION OCCURRING DUE TO THE TROPICAL WAVE ALONG
25W...NO OTHER CONVECTION IS OBSERVED AT THIS TIME.

...DISCUSSION...

GULF OF MEXICO...

A BROAD SURFACE HIGH COVERS THE EASTERN CONUS AND EXTENDS ACROSS
THE GULF WATERS. A WEAKNESS IN THIS HIGH IS ANALYZED AS A 1013
MB SURFACE LOW LOCATED NEAR 29N84W. ISOLATED MODERATE CONVECTION
PREVAILS E OF 84W AND MOVING NE AFFECTING MOSTLY THE FLORIDA
PENINSULA. TO THE W...AN ELONGATED UPPER-LEVEL LOW IS CENTERED
OVER THE N-CENTRAL GULF NEAR 28N90W AND EXTENDS ACROSS THE BASIN
SUPPORTING SCATTERED MODERATE CONVECTION S OF 28N BETWEEN 87W-
95W. SCATTEROMETER DATA DEPICTS LIGHT AND VARIABLE WINDS ACROSS
THE GULF. WEAK RIDGING WILL CONTINUE ACROSS THE BASIN OVER THE
NEXT 24-48 HOURS WHILE THE SURFACE LOW WILL MOVE N OVER
THE FLORIDA PANHANDLE WITH CONVECTION.

CARIBBEAN SEA...

TWO TROPICAL WAVES ARE OVER THE BASIN. SEE THE TROPICAL WAVES
SECTION FOR MORE DETAILS. THE EASTERN PORTION OF AN UPPER-LEVEL
TROUGH EXTENDS FROM THE GULF OF MEXICO ACROSS THE W CARIBBEAN.
THE W AND CENTRAL CARIBBEAN BETWEEN 72W-85W IS UNDER THE
INFLUENCE OF AN UPPER-LEVEL HIGH CENTERED NEAR 12N80W. TO THE
E...AN UPPER-LEVEL LOW EXTENDS FROM SOUTH AMERICA ACROSS THE SE
CARIBBEAN BETWEEN 66W-72W WHILE THE WESTERN PORTION OF A WEAK
ANTICYCLONE CENTERED OVER THE ATLANTIC EXTENDS ACROSS THE E
CARIBBEAN MAINLY E OF 67W. ASIDE FROM THE CONVECTION RELATED TO
THE TROPICAL WAVE ALONG 64W...THE ONLY CONVECTION OBSERVED
ACROSS THE BASIN IS DUE TO THE PROXIMITY OF THE MONSOON TROUGH
ACROSS THE SOUTHERN CARIBBEAN S OF 12N BETWEEN 80W-84W.
SCATTEROMETER DATA DEPICTS GENTLE TO MODERATE TRADES ACROSS THE
AREA BECOMING FRESH S OF 13N BETWEEN 72W-78W. OVER THE NEXT 24
HOURS...THE TROPICAL WAVES WILL CONTINUE MOVING W. CONVECTION
WILL PREVAIL ACROSS THE SOUTHERN CARIBBEAN WITH THE MONSOON
TROUGH.

...HISPANIOLA...

FAIR WEATHER PREVAILS ACROSS THE ISLAND AT THIS TIME. AFTERNOON
SHOWERS COULD BE EXPECTED DUE TO OROGRAPHIC LIFTING AND DAYTIME
HEATING. A TROPICAL WAVE WILL MOVE ACROSS THE ISLAND WITHIN THE
NEXT 24-48 HOURS SUPPORTING CONVECTION.

ATLANTIC OCEAN...

TROPICAL DEPRESSION GRACE IS MOVING ACROSS THE CENTRAL ATLANTIC.
PLEASE REFER TO THE SPECIAL FEATURES SECTION FOR MORE DETAILS.
TWO TROPICAL WAVES ARE ALSO MOVING ACROSS THE TROPICAL ATLANTIC.
PLEASE REFER TO THE TROPICAL WAVES SECTION FOR MORE DETAILS.
UPPER-LEVEL DIFFLUENCE IS SUPPORTING ISOLATED MODERATE
CONVECTION ACROSS THE W ATLANTIC MAINLY W OF 77W. THE MAJORITY
OF THE BASIN IS UNDER THE INFLUENCE OF A SURFACE
RIDGE...ANCHORED BY A 1018 MB HIGH NEAR 26N64W AND A 1021 MB
HIGH CENTERED NEAR 29N28W. TO THE N OF THE RIDGE...A STATIONARY
FRONT EXTENDS FROM 35N74W TO A 1014 MB LOW NEAR 31N60W TO 29N46W
TO 32N31W. ASIDE FROM THE CONVECTION RELATED TO THE LOW PRESSURE
...SEE THE SPECIAL FEATURES SECTION FOR MORE DETAILS...ISOLATED
MODERATE CONVECTION IS OBSERVED N OF 29N BETWEEN 62W-70W AND N
OF 29N BETWEEN 38W-42W.

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

$$

ERA
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