[Tropical] Tropical Weather Discussion

[EMWIN Server]

AXNT20 KNHC 231719
TWDAT

TROPICAL WEATHER DISCUSSION
NWS NATIONAL HURRICANE CENTER MIAMI FL
205 PM EDT WED SEP 23 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
1715 UTC.

...SPECIAL FEATURES...

THE CENTER OF TROPICAL STORM IDA AT 23/1500 UTC IS NEAR 20.0N
47.0W. IDA IS MOVING TOWARD THE E...OR 90 DEGREES AT 4 KNOTS.
THE MINIMUM CENTRAL PRESSURE IS 1005 MB. THE MAXIMUM SUSTAINED
WIND SPEED IS 35 KNOTS WITH GUSTS TO 45 KNOTS. UPPER-LEVEL SHEAR
CONTINUES DETERIORATING THE SYSTEM THAT IS CURRENTLY EMBEDDED IN
THE BASE OF AN UPPER-LEVEL TROUGH. SCATTERED MODERATE TO STRONG
CONVECTION IS OBSERVED FROM 17N-21N BETWEEN 41W-46W WHILE A
CLUSTER OF SCATTERED MODERATE CONVECTION EXTENDS FROM 20N-29N
BETWEEN 33W-42W. PUBLIC ADVISORIES ABOUT TROPICAL STORM IDA ARE
BEING ISSUED UNDER THE WMO HEADER WTNT35 KNHC...AND UNDER THE
AWIPS HEADER MIATCPAT5. FORECAST/ADVISORIES ABOUT TROPICAL STORM
IDA ARE BEING ISSUED UNDER THE WMO HEADER WTNT25 KNHC...AND
UNDER THE AWIPS HEADER MIATCMAT5.

...TROPICAL WAVES...

A TROPICAL WAVE IS OVER THE E ATLANTIC WATERS WITH AXIS E OF THE
CAPE VERDE ISLANDS EXTENDING FROM 16N22W TO 06N25W...MOVING W AT
5-10 KT WITHIN THE LAST 24 HOURS. TPW IMAGERY SHOWS THE WAVE
EMBEDDED IN A MODERATE MOIST ENVIRONMENT WITH AN AREA OF HIGHER
MOISTURE FROM 14N-16N AND E OF 23W...WHICH COINCIDES WITH THE
AREA OF SCATTERED MODERATE CONVECTION OBSERVED ALONG THE
NORTHERN PORTION OF THE WAVE. ISOLATED CONVECTION IS OBSERVED
ELSEWHERE.

...ITCZ/MONSOON TROUGH...

THE MONSOON TROUGH EXTENDS FROM THE COAST OF WESTERN AFRICA NEAR
13N17W TO 05N25W TO 08N37W. ASIDE FROM THE CONVECTION ASSOCIATED
WITH THE TROPICAL WAVE...ISOLATED MODERATE CONVECTION IS WITHIN
50 NM N AND S OF THE AXIS MAINLY E OF 21W.

...DISCUSSION...

GULF OF MEXICO...

AN UPPER-LEVEL ANTICYCLONE PREVAILS ACROSS THE NORTHERN MEXICO
AREA AND EXTENDING ACROSS THE WESTERN GULF WATERS MAINLY W OF
90W. TO THE E...AN UPPER-LEVEL CYCLONE CENTERED OVER W GEORGIA
NEAR 33N84W EXTENDS ITS TROUGH ACROSS THE EASTERN GULF WATERS E
OF 90W. THIS TROUGH IS SUPPORTING SCATTERED MODERATE CONVECTION
ACROSS THIS AREA AND GENERATING A DIFFLUENT FLOW ACROSS THE
STRAITS OF FLORIDA AND THE SOUTHERN PORTION OF THE FLORIDA
PENINSULA PRODUCING SCATTERED MODERATE TO STRONG CONVECTION THAT
AFFECTING NOT ONLY THE ADJACENT SE GULF WATERS BUT PORTIONS OF
SOUTHERN FLORIDA. AT THE SURFACE...A SURFACE TROUGH EXTENDS
ACROSS THE BAY OF CAMPECHE FROM 23N92W TO 18N93W. NO CONVECTION
IS RELATED TO THIS FEATURE. ANOTHER SURFACE TROUGH EXTENDS FROM
28N85W TO 23N89W. ISOLATED MODERATE CONVECTION IS RELATED TO
THIS BOUNDARY. SCATTEROMETER DATA DEPICTS A GENTLE E-NE WIND
FLOW OVER THE N-NE BASIN WHILE LIGHT AND VARIABLE WINDS ARE OVER
THE REMAINDER GULF. OVER THE NEXT 24 HOURS...EXPECT FOR LOW
PRESSURE TO DOMINATE ACROSS THE BASIN. SURFACE RIDGING WILL
START TO BUILD ACROSS THE GULF BY FRIDAY.

CARIBBEAN SEA...

A DIFFLUENT FLOW PREVAILS ACROSS THE NW CARIBBEAN SUPPORTING
ISOLATED MODERATE CONVECTION MAINLY W OF 82W. A SURFACE TROUGH
WAS ANALYZED ACROSS THE SOUTHERN CARIBBEAN EXTENDING FROM 14N83W
TO A 1006 MB LOW CENTERED OVER NORTHERN COLOMBIA. CLUSTERS OF
MODERATE TO STRONG CONVECTION PREVAIL S OF 15N BETWEEN 76W-83W.
DRY AIR AND STRONG DEEP LAYER WIND SHEAR INHIBIT CONVECTIVE
ACTIVITY OVER THE REMAINDER OF THE CARIBBEAN. SCATTEROMETER DATA
DEPICTS GENTLE TRADES DOMINATING BETWEEN 70W-80W WHILE LIGHTER
WINDS PREVAIL ELSEWHERE. NO SIGNIFICANT WEATHER CHANGES ARE
EXPECTED OVER THE NEXT THREE DAYS.

...HISPANIOLA...

MAINLY CLEAR SKIES ARE ACROSS THE ISLAND AT THIS TIME INFLUENCED
BY DRY AIR SUBSIDENCE FROM RIDGING ALOFT AND STRONG DEEP LAYER
WIND SHEAR. DIURNAL AFTERNOON/EVENING SHOWERS ARE EXPECTED TO
DEVELOP LATER TODAY AND OVER THE NEXT 24 HOURS.

ATLANTIC OCEAN...

THE MAIN FEATURE IN THE BASIN IS TROPICAL STORM IDA...WHICH WAS
ALREADY DISCUSSED IN THE SPECIAL FEATURES SECTION ABOVE. ACROSS
THE W ATLANTIC...A 1012 MB SURFACE LOW CENTERED NEAR 33N76W
EXTENDS ITS STATIONARY FRONT TO 29N81W. SCATTERED MODERATE
CONVECTION IS OBSERVED N OF THE FRONTAL BOUNDARY AND W OF 79W. S
OF THE FRONT...A SURFACE TROUGH EXTENDS FROM 28N79W TO 25N80W.
THIS FEATURE COMBINED WITH UPPER-LEVEL DIFFLUENCE PREVAILING
ACROSS THIS AREA ARE SUPPORTING SCATTERED MODERATE CONVECTION
FROM 23N-29N BETWEEN 77W-80W. TO THE E...AN UPPER-LEVEL LOW
CENTERED NEAR 24N64W IS SUPPORTING SCATTERED MODERATE CONVECTION
FROM 20N27N BETWEEN 60W-68W. THE REMAINDER BASIN IS BEING
INFLUENCED BY A SURFACE RIDGE ANCHORED BY A 1025 MB HIGH NEAR
43N27W.

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

$$

ERA
This weather bulletin was brought to you by:
www.nashvilleweather.net