Tropical Weather Discussion
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000
AXNT20 KNHC 280530
TWDAT

TROPICAL WEATHER DISCUSSION
NWS NATIONAL HURRICANE CENTER MIAMI FL
205 AM EDT FRI AUG 28 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 0000 UTC SURFACE ANALYSIS AND SATELLITE IMAGERY THROUGH
0530 UTC.

...SPECIAL FEATURES...

TROPICAL STORM ERIKA IS CENTERED NEAR 16.6N 65.3W AT 28/0300 UTC
OR AT ABOUT 117 NM SSE OF SAN JUAN PUERTO RICO...MOVING W AT 15
KT. ESTIMATED CENTRAL PRESSURE IS 1008 MB. MAXIMUM SUSTAINED
WINDS ARE 40 KT WITH GUSTS TO 50 KT. NUMEROUS MODERATE TO STRONG
CONVECTION IS FROM 13N-19N BETWEEN 62W-66W. ERIKA IS EXPECTED TO
PRODUCE TOTAL RAINFALL ACCUMULATIONS OF 4 TO 8 INCHES WITH
MAXIMUM AMOUNTS OF 12 INCHES POSSIBLE ACROSS PORTIONS OF THE
LEEWARD ISLANDS...VIRGIN ISLANDS...AND PUERTO RICO
OVERNIGHT...AND OVER THE DOMINICAN REPUBLIC...TURKS AND CAICOS
ISLANDS AND SOUTHERN BAHAMAS THROUGH SATURDAY. RAINS COULD CAUSE
LIFE-THREATENING FLASH FLOODS AND MUD SLIDES. PLEASE SEE THE
LATEST FORECAST/ADVISORY UNDER AWIPS/WMO HEADERS
MIATCMAT5/WTNT25 KNHC AND THE HIGH SEAS FORECAST PRODUCT
UNDER AWIPS/WMO HEADERS MIAHSFAT1/FZNT02 KNHC FOR MORE DETAILS.

...TROPICAL WAVES...

A TROPICAL WAVE IS OVER THE E ATLANTIC WITH AXIS EXTENDING FROM
15N32W TO A 1012 LOW NEAR 10N34W TO 07N34W...MOVING W AT ABOUT
20 KT OVER THE PAST 24 HOURS. MODERATE MOISTURE PREVAILS IN THE
ENVIRONMENT OF THIS WAVE AS NOTED IN TPW IMAGERY. SCATTERED
MODERATE CONVECTION IS FROM 07N-14N BETWEEN 31W-42W.

A TROPICAL WAVE IS OVER THE CENTRAL ATLANTIC WITH AXIS EXTENDING
FROM 20N46W TO 08N48W...MOVING W AT 15-20 KT OVER THE PAST 24
HOURS. MODERATE MOISTURE FROM THE SURFACE TO NEARLY 700 MB IS
ASSOCIATED WITH THIS WAVE AS INDICATED BY CIRA LAYER
PRECIPITABLE WATER IMAGERY. HOWEVER...THE PRESENCE OF SAHARAN
DRY AIRMASS IN THE WAVE ENVIRONMENT IS CURRENTLY SUPPRESSING ANY
CONVECTION.

...ITCZ/MONSOON TROUGH...

THE MONSOON TROUGH AXIS EXTENDS INTO THE TROPICAL ATLANTIC NEAR
13N17W TO 14N27W TO A 1012 MB LOW NEAR 10N34W TO 09N38W. THE
ITCZ BEGINS FROM THAT POINT TO 08N46W. ASIDE FROM THE CONVECTION
RELATED TO THE TROPICAL WAVE ALONG 34W...ISOLATED MODERATE
CONVECTION IS OBSERVED FROM 06N-10N BETWEEN 41W-47W.

...DISCUSSION...

GULF OF MEXICO...

A BROAD MID TO UPPER-LEVEL TROUGH EXTENDS FROM THE OHIO VALLEY
TO THE S-SW ACROSS THE GULF TO A BASE OVER THE BAY OF CAMPECHE.
THIS TROUGH SUPPORTS A STATIONARY FRONT THAT EXTENDS FROM
NORTHERN FLORIDA TO A 1013 MB LOW NEAR 29N85W TO 23N88W TO
24N96W. SCATTERED MODERATE CONVECTION IS OBSERVED ALONG THE
FRONTAL BOUNDARY. THE UPPER-LEVEL TROUGH ALSO SUPPORTS A SURFACE
TROUGH E OF THE FRONT EXTENDING FROM 31N82W TO 24N84W WITH
ISOLATED CONVECTION. UPPER LEVEL DIFFLUENCE IS SUPPORTING
ISOLATED CONVECTION ACROSS THE SOUTHERN GULF MAINLY S OF THE
FRONT WHILE SCATTERED MODERATE CONVECTION PREVAILS ACROSS THE
GULF WATERS S OF 25N AND E OF 85W. SCATTEROMETER DATA DEPICTS A
LIGHT TO GENTLE NORTHERLY FLOW ACROSS THE BASIN. OVER THE NEXT
24 HOURS...EXPECT FOR THE FRONTAL BOUNDARY TO PREVAIL ACROSS THE
SOUTHERN HALF OF THE GULF WITH CONVECTION.

CARIBBEAN SEA...

THE MAIN FEATURE OF INTEREST IN THE BASIN IS TROPICAL STORM
ERIKA CURRENTLY MOVING OVER THE E CARIBBEAN. PLEASE REFER TO THE
SPECIAL FEATURES SECTION FOR MORE DETAILS. UPPER-LEVEL
DIFFLUENCE GENERATED BY THE PROXIMITY OF THE UPPER-LEVEL TROUGH
OVER THE GULF COMBINED WITH SUFFICIENT LOW LEVEL MOISTURE ARE
SUPPORTING SCATTERED MODERATE CONVECTION ACROSS THE WESTERN HALF
OF CUBA AFFECTING THE NW CARIBBEAN AND THE STRAITS OF FLORIDA.
FAIR WEATHER PREVAILS ACROSS THE REMAINDER OF THE BASIN.
SCATTEROMETER DATA DEPICTS LIGHT TO GENTLE TRADES ACROSS THE W
AND CENTRAL CARIBBEAN AND HIGHER WINDS SURROUNDING ERIKA MAINLY
E OF 71W. OVER THE NEXT 24 HOURS...EXPECT FOR ERIKA TO CONTINUE
MOVING ACROSS THE E CARIBBEAN THEN MOVE NW ENTERING THE SW
ATLANTIC.

...HISPANIOLA...

FAIR WEATHER PREVAILS ACROSS THE ISLAND AT THIS TIME. THE CENTER
OF TROPICAL STORM ERIKA IS EXPECTED TO MOVE NEAR OR OVER
DOMINICAN REPUBLIC OVER THE NEXT 12-18 HOURS. ERIKA IS EXPECTED
TO PRODUCE TOTAL RAINFALL ACCUMULATIONS OF 4 TO 8 INCHES WITH
MAXIMUM AMOUNTS OF 12 INCHES POSSIBLE ACROSS PORTIONS OF THE
ISLAND THROUGH SATURDAY. RAINS COULD CAUSE LIFE-THREATENING
FLASH FLOODS AND MUD SLIDES.

ATLANTIC OCEAN...

UPPER-LEVEL DIVERGENCE ACROSS THE W ATLANTIC IS SUPPORTING
ISOLATED CONVECTION ACROSS THE BAHAMAS MAINLY W OF 74W.  TO THE
SE...SCATTERED MODERATE CONVECTION ASSOCIATED WITH TROPICAL
STORM ERIKA...DISCUSSED IN THE SPECIAL FEATURES SECTION
ABOVE...IS S OF 20N BETWEEN 62W-66W. TWO TROPICAL WAVES ARE
MOVING ACROSS THE E AND CENTRAL TROPICAL ATLANTIC. PLEASE SEE
THE TROPICAL WAVES SECTION FOR MORE DETAILS. THE REMAINDER OF
THE BASIN IS DOMINATED BY A SURFACE RIDGE ANCHORED BY A 1020 MB
HIGH NEAR 29N64W AND A 1021 MB HIGH NEAR 29N27W.

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

$$

ERA



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