Tropical Weather Discussion
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000
AXNT20 KNHC 271032
TWDAT

TROPICAL WEATHER DISCUSSION
NWS NATIONAL HURRICANE CENTER MIAMI FL
805 AM EDT THU AUG 27 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 0600 UTC SURFACE ANALYSIS AND SATELLITE IMAGERY THROUGH
1030 UTC.

...SPECIAL FEATURES...

TROPICAL STORM ERIKA IS SHOWING SOME SIGNS OF
STRENGTHENING...CURRENTLY CENTERED NEAR 16.8N 61.5W OR ABOUT 26
NM SE OF ANTIGUA...MOVING W AT 14 KT. ESTIMATED CENTRAL PRESSURE
IS 1003 MB. MAXIMUM SUSTAINED WINDS ARE 45 KT WITH GUSTS TO 55
KT. A CLUSTER OF MODERATE TO STRONG CONVECTION IS FROM 13N-19N
BETWEEN 56W-65W. PLEASE SEE THE LATEST FORECAST/ADVISORY UNDER
AWIPS/WMO HEADERS MIATCMAT5/WTNT25 KNHC FOR MORE DETAILS.

...TROPICAL WAVES...

A TROPICAL WAVE IS OVER THE E ATLANTIC WITH AXIS EXTENDING FROM
16N23W TO 09N23W...MOVING W AT ABOUT 15 KT OVER THE PAST 12 HRS.
DESPITE THE FACT THAT MODERATE MOISTURE IS DEPICTED WITH THIS
WAVE IN TPW IMAGERY...ONLY ISOLATED CONVECTION PREVAILS FROM 07N-
10N BETWEEN 21W-25W.

A TROPICAL WAVE IS OVER THE CENTRAL ATLANTIC WITH AXIS EXTENDING
FROM 21N41W TO 11N42W...MOVING W AT 15 KT DURING THE PAST 24
HOURS. A BROAD AREA OF MODERATE MOISTURE IS ASSOCIATED WITH THIS
WAVE AS INDICATED BY TPW IMAGERY. THE PRESENCE OF A SAHARAN
AIRMASS IS LIMITING SIGNIFICANT CONVECTION TO THE NORTHERN
PORTION OF THE WAVE N OF 19N BETWEEN 38W-42W.

...ITCZ/MONSOON TROUGH...

THE MONSOON TROUGH AXIS EXTENDS INTO THE TROPICAL ATLANTIC NEAR
19N16W TO 15N21W THEN W OF A TROPICAL WAVE FROM 09N26W TO A 1012
MB LOW NEAR 10N30W TO 09N42W. ASIDE THE CONVECTION ASSOCIATED
WITH THE WAVE NEAR THE CAPE VERDE ISLANDS...ISOLATED SHOWERS ARE
WITHIN 100 NM N OF THE AXIS E OF 33W.

...DISCUSSION...

GULF OF MEXICO...

A BROAD MID TO UPPER-LEVEL TROUGH EXTENDS FROM THE OHIO VALLEY S-
SW ACROSS THE GULF WITH BASE OVER THE YUCATAN PENINSULA AND BAY
OF CAMPECHE. THIS TROUGH SUPPORTS A STATIONARY FRONT THAT
EXTENDS FROM A 1013 MB LOW CENTERED OVER E GEORGIA ACROSS
NORTHERN FLORIDA TO 30N84W TO 25N88W TO 24N94W. ISOLATED
MODERATE CONVECTION IS OBSERVED ALONG THE FRONT. TO THE W OF THE
FRONT...SCATTERED MODERATE CONVECTION PREVAILS OVER THE BAY OF
CAMPECHE FROM 19N-22N AND W OF 94W. THE COMBINATION OF THE
PROXIMITY OF THE FRONT AND UPPER LEVEL DIFFLUENCE ARE SUPPORTING
ISOLATED CONVECTION ACROSS THE SE GULF MAINLY E OF 92W WITH
SCATTERED MODERATE CONVECTION BETWEEN 24N-27N AND E OF 85W.
SCATTEROMETER DATA DEPICTS A LIGHT TO GENTLE NORTHERLY FLOW
PREVAILING ACROSS THE BASIN. OVER THE NEXT 24 HOURS...EXPECT FOR
THE STATIONARY FRONT TO WEAKEN AND BEGIN TO DISSIPATE. A LOW
PRESSURE CENTER IS FORECAST TO DEVELOP OVER NORTHERN FLORIDA
SUPPORTING CONVECTION ACROSS THE NE GULF.

CARIBBEAN SEA...

AN ELONGATED UPPER-LEVEL LOW EXTENDS FROM THE CENTRAL BAHAMAS S-
SW ACROSS THE CENTRAL CARIBBEAN. THIS FEATURE COMBINED WITH
SHALLOW MOISTURE ARE SUPPORTING ISOLATED CONVECTION ACROSS THE W
AND CENTRAL CARIBBEAN MAINLY W OF 77W. A SURFACE
TROUGH...REMNANT OF DANNY...PREVAILS ACROSS HAITI EXTENDING FROM
22N73W TO 19N74W. ISOLATED MODERATE CONVECTION IS OBSERVED ALONG
THIS BOUNDARY MAINLY N OF 19N. THE CENTER OF TROPICAL STORM
ERIKA IS CURRENTLY MOVING OVER THE LEEWARD ISLANDS ENHANCING
CONVECTION ACROSS THE E CARIBBEAN E OF 64W AFFECTING NOT ONLY
THE LESSER ANTILLES BUT PUERTO RICO AND THE VIRGIN ISLANDS. FOR
MORE INFORMATION ABOUT ERIKA...PLEASE REFER TO THE SECTION
ABOVE. SCATTEROMETER DATA DEPICTS LIGHT TO GENTLE TRADES ACROSS
THE BASIN EXCEPT GENTLE TO MODERATE WINDS S OF 14N BETWEEN 72W-
77W. OVER THE NEXT 24 HOURS...EXPECT FOR ERIKA TO MOVE ACROSS
THE NE CARIBBEAN WITH CONVECTION.

...HISPANIOLA...

THE REMNANTS OF DANNY REMAIN W OF THE ISLAND IN THE FORM OF A
SURFACE TROUGH SUPPORTING ISOLATED SHOWERS ACROSS HAITI. OVER
THE NEXT 24 HOURS...EXPECT FOR THE TROUGH TO MOVE W AWAY FROM
THE ISLAND AS TROPICAL STORM ERIKA APPROACHES FROM THE E WITH
CONVECTION.

ATLANTIC OCEAN...

THE MAIN FEATURE IN THE TROPICAL ATLANTIC IS TROPICAL STORM
ERIKA. FOR MORE DETAILS PLEASE REFER TO THE SECTION ABOVE. TWO
TROPICAL WAVES ARE MOVING ACROSS THE E AND CENTRAL ATLANTIC.
REFER TO THE TROPICAL WAVES SECTION ABOVE FOR DETAILS. A BROAD
MID TO UPPER-LEVEL TROUGH EXTENDS FROM THE OHIO VALLEY S-SW
ACROSS THE GULF TO A BASE OVER THE YUCATAN PENINSULA SUPPORTING
A STATIONARY FRONT THAT IS CURRENTLY EXTENDING FROM
GEORGIA...ACROSS NORTHERN FLORIDA THEN INTO THE GULF OF MEXICO.
A SURFACE TROUGH IS SE OF THE FRONTAL BOUNDARY FROM 31N80W TO
27N80W. SCATTERED MODERATE CONVECTION PREVAILS ALONG THE TROUGH
AFFECTING THE W ATLANTIC MAINLY W OF 75W. TO THE E...A SURFACE
RIDGE EXTENDS ACROSS THE REMAINDER OF THE BASIN ANCHORED BY A
1019 MB HIGH PRESSURE CENTERED NEAR 28N60W AND A 1021 MB HIGH
NEAR 31N25W. OVER THE NEXT 24 OURS...EXPECT FOR ERIKA TO ENTER
THE NE CARIBBEAN WITH CONVECTION. SHOWERS AND THUNDERSTORMS WILL
PREVAIL ACROSS THE W ATLANTIC.

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

$$

ERA



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