[Tropical] Tropical Weather Discussion

[EMWIN Server]

AXNT20 KNHC 081747
TWDAT

TROPICAL WEATHER DISCUSSION
NWS NATIONAL HURRICANE CENTER MIAMI FL
205 PM EDT WED OCT 08 2014

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.

...TROPICAL WAVES...

A TROPICAL WAVE IS OVER THE EASTERN ATLANTIC EXTENDING FROM
15N20W TO A 1011 MB SURFACE LOW NEAR 9N20W TO 7N21W MOVING
WESTWARD AT 10-15 KT. SSMI TPW IMAGERY AND WATER VAPOR IMAGERY
INDICATE THAT THE WAVE IS EMBEDDED IN AN ENVIRONMENT WITH HIGH
DEEP LAYER MOISTURE AND COINCIDES WITH A DIFFLUENT ENVIRONMENT
ALOFT. SCATTERED MODERATE AND ISOLATED STRONG CONVECTION IS FROM
7N-14N BETWEEN 19W AND 25W.

A TROPICAL WAVE IS OVER THE CENTRAL ATLANTIC WITH AXIS EXTENDING
FROM 16N45W TO 7N45W...MOVING W AT 10-15 KT. SSMI TPW IMAGERY
INDICATE THIS WAVE IS EMBEDDED IN A LARGE AREA OF MODERATE
MOISTURE. AN UPPER TROUGH TO THE NORTH OF THE WAVE IS PRODUCING
WESTERLY UPPER LEVEL WINDS OVER THE NORTHERN PORTION OF THE
WAVE. SCATTERED MODERATE CONVECTION IS FROM 12N TO 19N BETWEEN
42W AND 50W.  SCATTERED SHOWERS ARE S OF 13N WITHIN 100 NM OF
THE WAVE AXIS.

A TROPICAL WAVE IS MOVING ACROSS THE EASTERN CARIBBEAN WITH AXIS
EXTENDING FROM 19N66W TO 10N67W...MOVING W AT 15 KT. SSMI TPW
SHOWS THIS WAVE IS EMBEDDED IN A AREA OF HIGH MOISTURE WHICH IS
SUPPORTING SCATTERED SHOWERS AND ISOLATED THUNDERSTORMS ACROSS
PUERTO RICO AND SURROUNDING ISLANDS.

...THE ITCZ/THE MONSOON TROUGH...

THE MONSOON TROUGH EXTENDS FROM THE COAST OF AFRICA NEAR 14N17W
TO A 1011 SURFACE LOW NEAR 9N20W. THE ITCZ EXTENDS FROM THE
SURFACE LOW NEAR 9N20W TO 12N40W. BESIDES THE CONVECTION
ASSOCIATED WITH THE TROPICAL WAVE AND SURFACE LOW...SCATTERED
MODERATE CONVECTION IS FROM 5N-18N BETWEEN 26W-42W.

...DISCUSSION...

GULF OF MEXICO...

A BROAD MID TO UPPER LEVEL TROUGH REMAINS OVER THE EASTERN CONUS
AND EXTENDS INTO THE NORTHERN GULF. AN UPPER LEVEL RIDGE IS OVER
W MEXICO WITH SUBSIDENCE OCCURRING ACROSS MUCH OF E MEXICO AND
THE W GULF BETWEEN THESE TWO FEATURES. DIFFLUENCE TO THE SOUTH
AND EAST OF THE UPPER TROUGH CONTINUES TO PRODUCE CLOUD COVER
AND SCATTERED SHOWERS FROM THE YUCATAN N TO 26N BETWEEN 82W AND
90W. A SURFACE TROUGH IS FROM 24N90W THROUGH THE BAY OF CAMPECHE
TO THE MEXICO COAST NEAR 18N94W. SCATTERED SHOWERS AND ISOLATED
THUNDERSTORMS ARE WITHIN 50 NM OF THIS TROUGH AXIS. OVER THE
NEXT 24 HOURS THE UPPER TROUGH WILL LIFT OUT OF THE BASIN WHILE
THE UPPER RIDGE SHIFTS WEST INTO THE BASIN. SUBSIDENCE BETWEEN
THESE TWO FEATURES SHOULD LIMIT AREAS OF CONVECTION.
HOWEVER...THE SURFACE TROUGH WILL REMAIN THE FOCUS FOR SCATTERED
SHOWERS AND ISOLATED THUNDERSTORMS AS IT MOVES ACROSS THE W GULF
AND REMAINS IN THE BAY OF CAMPECHE ON THURSDAY.

CARIBBEAN SEA...

SCATTERED MODERATE AND ISOLATED STRONG CONVECTION ARE ACROSS THE
SW CARIBBEAN ASSOCIATED WITH A 1009 MB LOW CENTERED OVER WESTERN
COSTA RICA NEAR 10N85W. A TROPICAL WAVE IS IN THE EASTERN
CARIBBEAN...SEE THE TROPICAL WAVES SECTION ABOVE. DRY AIR IS
LIMITING CONVECTION ACROSS THE GREATER ANTILLES WEST OF PUERTO
RICO AND THE NW CARIBBEAN. ACROSS CUBA...HISPANIOLA...AND
JAMAICA...DUST AND HAZE CONTINUE TO BE REPORTED. THIS HAZE AND
DUST IS ASSOCIATED WITH A SAHARAN AIRMASS. SURFACE TRADE WINDS
OF 10 TO 20 KT DOMINATE THE BASIN. OVER THE NEXT 24
HOURS...ENHANCED CONVECTION IS EXPECTED TO CONTINUE ACROSS THE
SW CARIBBEAN IN THE PRESENCE OF UPPER LEVEL DIFFLUENCE AND THE
SLOW MOVING SURFACE LOW. SCATTERED SHOWERS AND THUNDERSTORMS
WILL BE POSSIBLE IN THE CENTRAL CARIBBEAN ALONG THE WESTWARD
MOVING TROPICAL WAVE. A SURFACE TROUGH IN THE ATLANTIC
APPROACHING THE LESSER ANTILLES MAY BRING AN INCREASE IN SHOWER
AND THUNDERSTORMS ACTIVITY TO THOSE ISLANDS LATER ON THURSDAY
AND ON FRIDAY.

...HISPANIOLA...

DRY CONDITIONS AND HAZE CONTINUE ACROSS THE ISLAND IN THE
PRESENCE OF SAHARAN AIR. MOISTURE WILL SLOWLY INCREASE TONIGHT
AND THURSDAY AS A TROPICAL WAVE MOVES ACROSS THE AREA...AND A
SURFACE TROUGH APPROACHES FROM THE WEST. ISOLATED SHOWERS AND
THUNDERSTORMS WILL BE POSSIBLE THURSDAY AND FRIDAY.

ATLANTIC OCEAN...

ASCENT ON THE SOUTH AND EASTERN SIDE OF A TROUGH OVER THE
EASTERN CONUS CONTINUES TO ENHANCE CLOUD COVER AND PRODUCE
ISOLATED SHOWERS AND THUNDERSTORMS FROM S FL ACROSS THE NORTHERN
BAHAMAS AND NORTHEASTWARD TO NEAR 30N75W. A SURFACE TROUGH IS
FROM 22N59W TO 14N58W. AN UPPER LOW IS OVER THIS SURFACE TROUGH
NEAR 21N60W. SCATTERED MODERATE CONVECTION IS OCCURRING MAINLY W
OF THE TROUGH FROM 14N TO 24N BETWEEN 52W AND 58W. SCATTERED
SHOWERS AND ISOLATED THUNDERSTORMS ARE ALSO WITHIN 150 NM EAST
OF THE TROUGH AXIS. OVER THE NEXT 24 HOURS EXPECT THE SURFACE
TROUGH AND UPPER LOW TO SHIFT WEST WITH ONGOING CONVECTION. THE
UPPER TROUGH OVER THE EASTERN CONUS WILL BEGIN TO LIFT AND SLIDE
EAST. THIS SHOULD BRING A FOCUS OF CLOUD COVER AND SHOWERS EAST
OF THE BAHAMAS BY THURSDAY.

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

$$
LATTO

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