[Tropical] Tropical Weather Discussion

[EMWIN Server]

AXNT20 KNHC 191041
TWDAT

TROPICAL WEATHER DISCUSSION
NWS NATIONAL HURRICANE CENTER MIAMI FL
805 AM EDT WED AUG 19 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 DANNY IS LOCATED NEAR 11.3N 40.2W AT 0900
UTC...MOVING WEST AT 12 KT. ESTIMATED MINIMUM CENTRAL PRESSURE
IS 1000 MB. MAXIMUM SUSTAINED WIND SPEED IS 45 KT WITH GUSTS TO
55 KT. CLUSTERS OF SCATTERED MODERATE CONVECTION ARE FROM 05N TO
13N BETWEEN 36W AND 42W. SOME ADDITIONAL STRENGTHENING IS
FORECAST DURING THE NEXT 48 HOURS AND DANNY COULD BECOME A
HURRICANE ON THURSDAY. PLEASE SEE LATEST NHC FORECAST/ADVISORY
UNDER AWIPS/WMO HEADERS TCMAT4/WTNT24 KNHC FOR MORE DETAILS.

...TROPICAL WAVES...

A TROPICAL WAVE IS EAST OF THE CAPE VERDE ISLANDS WITH AXIS NEAR
21W...MOVING W AT 5-10 KT OVER THE PAST 21 HOURS. CIRA LAYER
PRECIPITABLE WATER IMAGERY SHOW THE WAVE IS WITHIN A MODERATE
MOIST ENVIRONMENT EXTENDING FROM THE SURFACE TO 700 MB.
HOWEVER...METEOSAT ENHANCED IMAGERY SHOW SAHARAN DRY AIR AND
DUST IN THE WAVE ENVIRONMENT...WHICH IS KEEPING THE WAVE DEVOID
OF CONVECTION.

A TROPICAL WAVE IS WITHIN 220 NM E-SE OF THE LESSER ANTILLES
WITH AXIS NEAR 58W...MOVING W AT 10-15 KT OVER THE PAST 24
HOURS. CIRA LAYER PRECIPITABLE WATER IMAGERY SHOW THE WAVE IS
WITHIN A MODERATE MOIST ENVIRONMENT EXTENDING FROM THE SURFACE
TO 700 MB THAT ALONG WITH A DIFFLUENT ENVIRONMENT ALOFT SUPPORT
A CLUSTER OF MODERATE CONVECTION AND ISOLATED TSTMS FROM 06N TO
09N BETWEEN 57W AND 60W.

...ITCZ/MONSOON TROUGH...

THE MONSOON TROUGH EXTENDS ACROSS AFRICA INTO THE E TROPICAL
ATLC NEAR 14N18W...THEN RESUMES W OF A TROPICAL WAVE NEAR 12N22W
TO E OF T.S. DANNY NEAR 11N34W. THE ITCZ BEGINS W OF T.S. DANNY
NEAR 09N42W TO E OF THE WESTERNMOST TROPICAL WAVE NEAR 08N53W.
ASIDE THE CONVECTION ASSOCIATED WITH DANNY AND THE TROPICAL
WAVE...SCATTERED MODERATE CONVECTION IS FROM 07N TO 14N BETWEEN
23W AND 35W AND FROM 04N TO 11N BETWEEN 41W AND 52W.

...DISCUSSION...

GULF OF MEXICO...

A BROAD MIDDLE TO UPPER LEVEL RIDGE CONTINUE OVER THE GULF
ANCHORED NEAR 26N87W...WHICH IS SUPPORTING AN OVERALL STABLE
ENVIRONMENT ACROSS THE BASIN. THE ONLY AREA OF CONVECTION IS OFF
THE SE COAST OF TEXAS AND SW COAST OF LOUISIANA N OF 27N WHERE
HEAVY SHOWERS AND TSTMS ARE BEING FUELED BY MOISTURE INFLOW FROM
THE CARIBBEAN SEA AND SUPPORTED BY DIFFLUENCE BETWEEN THE UPPER
RIDGE AND AN UPPER TROUGH WITH BASE NEAR CENTRAL MEXICO. BROAD
SURFACE HIGH PRESSURE ACROSS THE ATLC EXTENDS A RIDGE AXIS W-SW
ACROSS THE FLORIDA PENINSULA TO THE SW GULF...THUS PROVIDING SE
WIND FLOW OF LESS THAN 15 KT BASIN-WIDE. SURFACE RIDGE WILL
EXTEND ACROSS THE N GULF THROUGH THU.

CARIBBEAN SEA...

AN UPPER LOW COVERS THE CARIBBEAN W OF 76W GENERATING A
DIFFLUENT ENVIRONMENT OVER THE FAR NW BASIN...WHICH ALONG WITH
SHALLOW MOISTURE SUPPORT SHOWERS AND THUNDERSTORMS N OF 19N
BETWEEN 79W AND 84W OR COASTAL WATERS OF WESTERN AND CENTRAL
CUBA. SCATTERED MODERATE CONVECTION AND TSTMS ARE OBSERVED
WITHIN 60 NM OFF THE COASTS OF COSTA RICA AND NORTHERN PANAMA
SUPPORTED BY THE EPAC MONSOON TROUGH. DRY AIR AND STRONG DEEP
LAYER WIND SHEAR HINDER CONVECTION ELSEWHERE ACROSS THE
CARIBBEAN. FRESH TO STRONG TRADES WILL CONTINUE OVER THE
S/CENTRAL CARIBBEAN INCREASING TO NEAR GALE FORCE OFF THE NW
COAST OF COLOMBIA ON WED NIGHT. TROPICAL WAVE WILL ENTER THE E
CARIBBEAN LATE TODAY AND MOVE INTO CENTRAL CARIBBEAN WATERS
THURSDAY.

...HISPANIOLA...

EXCEPT FOR PORTIONS OF WESTERN HAITI AND THE WINDWARD PASSAGE
WHERE MODERATE SHALLOW MOISTURE IS OBSERVED IN CIRA LAYER
PRECIPITABLE WATER IMAGERY...DEEP LAYER DRY AIR IS OVER THE
ISLAND SUPPORTING FAIR WEATHER. CLOUDINESS WITH POSSIBLE
ISOLATED SHOWERS CONTINUE MAINLY OFF THE WESTERN COAST OF HAITI.
MOISTURE AND THE CHANCE OF SHOWERS AND TSTMS IN THE REGION MAY
INCREASE THU NIGHT WITH THE PASSAGE OF A TROPICAL WAVE ACROSS
THE CENTRAL CARIBBEAN.

ATLANTIC OCEAN...

THE MAIN FEATURE IN THE BASIN IS TROPICAL STORM DANNY WHICH
COULD HAVE THE POTENTIAL TO STRENGTHEN INTO A HURRICANE DURING
THE NEXT COUPLE OF DAYS. SEE SPECIAL FEATURES FOR MORE DETAILS.
THE SECOND FEATURE OF INTEREST ARE TWO TROPICAL WAVES DISCUSSED
IN THE WAVES SECTION. OTHERWISE...THE ATLC IS DOMINATED BY A
SURFACE RIDGE ANCHORED BY A 1021 MB HIGH NEAR 29N48W. THE
SURFACE RIDGE ACROSS THE W ATLC WILL SHIFT S AS A WEAK TROUGH
PASSES E ACROSS N PORTION OF THE W ATLC S OF BERMUDA ON WED WITH
LOW DEVELOPING NEAR S OF BERMUDA ON THU NIGHT.

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

$$
NR
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