[Tropical] Tropical Weather Discussion

[EMWIN Server]

AXNT20 KNHC 050004
TWDAT

TROPICAL WEATHER DISCUSSION
NWS NATIONAL HURRICANE CENTER MIAMI FL
805 PM EDT SUN OCT 04 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 1800 UTC SURFACE ANALYSIS AND SATELLITE IMAGERY THROUGH
2315 UTC.

...SPECIAL FEATURES...

HURRICANE JOAQUIN IS CENTERED NEAR 32.2N 66.4W AT 04/2100 UTC OR
83 NM W OF BERMUDA MOVING NNE AT 12 KT. ESTIMATED MINIMUM
CENTRAL PRESSURE IS 958 MB. MAXIMUM SUSTAINED WIND SPEED IS 85
KT WITH GUSTS TO 105 KT. NUMEROUS MODERATE CONVECTION IS WITHIN
160 NM OF THE CENTER. SCATTERED MODERATE CONVECTION IS ELSEWHERE
WITHIN 360 NM IN THE NE SEMICIRCLE. SEE LATEST INTERMEDIATE
PUBLIC ADVISORY UNDER AWIPS/WMO HEADERS MIATCPAT1/WTNT31 KNHC
AND THE LATEST FULL NHC FORECAST/ADVISORY UNDER AWIPS/WMO
HEADERS MIATCMAT1/WTNT21 KNHC FOR MORE DETAILS.

...TROPICAL WAVES...

A TROPICAL WAVE IS OVER THE CENTRAL ATLC WITH AN AXIS EXTENDING
FROM 21N35W TO 10N40W WHERE THERE IS A 1010 MB SURFACE LOW. THIS
WAVE COINCIDES WITH A 700 MB TROUGH BETWEEN 34W AND 43W...AND A
850 MB MAXIMUM OF VORTICITY NEAR 12N30W. THIS WAVE IS EMBEDDED
IN AN ENVIRONMENT OF MODERATE TO HIGH MOISTURE AND HAS
DIFFLUENT FLOW ALOFT. NUMEROUS MODERATE CONVECTION IS FROM 10N
TO 14N BETWEEN 39W AND 42W. SCATTERED MODERATE CONVECTION IS
FROM 07N TO 16N BETWEEN 42W AND 46W.

...ITCZ/MONSOON TROUGH...

THE MONSOON TROUGH AXIS EXTENDS FROM NEAR 12N29W TO LOW PRES
NEAR 10N40W TO 10N46W TO 08N52W...WHERE THE ITCZ BEGINS AND
CONTINUES TO 07N58W. ASIDE FROM CONVECTION OCCURRING IN
ASSOCIATION WITH THE LOW AND ACCOMPANYING TROPICAL WAVE...
SCATTERED MODERATE CONVECTION IS FROM 04N TO 10N BETWEEN 25W AND
36W...AND FROM 09N TO 13N BETWEEN 51W AND 60W.

...DISCUSSION...

GULF OF MEXICO...
AN UPPER LEVEL ANTICYCLONE PREVAILS ACROSS THE SW GULF OF MEXICO
NEAR 22N96W...WHILE AN UPPER LOW IS OVER N FL NEAR 30N82W. VERY
DRY AIR COVERS THE GULF S OF 25N WITH SHALLOW MOISTURE EVIDENT N
OF 25N E OF 88W. THE UPPER LOW AND ASSOCIATED SURFACE LOWS TO
THE NE OF THE UPPER LOW SUPPORTS A SURFACE TROUGH OVER THE S
GULF THAT EXTENDS FROM 25N81W TO 23N95W. A SECONDARY TROUGH AS
OF 2100 UTC HAS BEEN RE-ANALYZED AS A COLD FRONT DUE TO A 16
DEGREE TEMPERATURE GRADIENT NOTED OVER FL. THIS FRONT AS OF 2100
UTC EXTENDS FROM 28N81W TO 27N90W. SCATTERED SHOWERS ARE WITHIN
30 NM OF THE SURFACE TROUGH. SCATTERED SHOWERS ARE WITHIN 50 NM
OF THE COLD FRONT...WITH A DECK OF STRATOCUMULUS ALONG AND N OF
THE COLD FRONT. A WEAK 1015 MB HIGH IS CENTERED NEAR 24N95W.
GENTLE TO MODERATE N TO NW WINDS DOMINATE THE GULF BASIN THIS
EVENING. THE UPPER LOW WILL MOVE SLOWLY EASTWARD OVER THE NEXT
24 HOURS WITH DEEP LAYER N TO NE FLOW FORECAST TO CONTINUE OVER
THE GULF THROUGH MONDAY. SHOWERS WILL REMAIN POSSIBLE IN SHALLOW
MOISTURE MAINLY OVER THE EASTERN GULF DURING THIS TIME. THE
SOUTHERNMOST TROUGH WILL GRADUALLY DISSIPATE. THE COLD FRONT
WILL BECOME STATIONARY BY MONDAY NIGHT AND TRANSITION TO A
TROUGH THROUGH TUESDAY FROM S FL TO THE SW GULF.

CARIBBEAN SEA...
AN UPPER LEVEL TROUGH OVER THE NW CARIBBEAN FROM CENTRAL CUBA TO
THE GULF OF HONDURAS SUPPORTS A SURFACE TROUGH WHICH EXTENDS
FROM 20N76W TO 16N83W. ISOLATED THUNDERSTORMS ARE WITHIN 60 NM
OF THE TROUGH AXIS N OF JAMAICA. SCATTERED MODERATE CONVECTION S
OF 11N OVER THE SW CARIBBEAN IS ASSOCIATED WITH THE E PACIFIC
MONSOON TROUGH AND DIURNAL THUNDERSTORM ACTIVITY OVER
COLOMBIA...VENEZUELA...AND PANAMA. ISOLATED THUNDERSTORMS ARE
OVER THE LEEWARD ISLANDS IN AN ENVIRONMENT OF MODERATE MOISTURE
AND NE FLOW ALOFT. GENTLE WINDS ARE OVER MUCH OF THE WESTERN
CARIBBEAN DUE TO WEAK STEERING FLOW AS THE INFLUENCES OF JOAQUIN
HAVE LIFTED NE OF THE REGION. SE TRADE WINDS OF 10 TO 15 KT
COVER THE EASTERN CARIBBEAN. OVER THE NEXT 24 HOURS ISOLATED
THUNDERSTORMS WILL BE POSSIBLE NEAR THE SURFACE TROUGH.

...HISPANIOLA...
THE COMBINATION OF MODERATE MOISTURE AND SOUTHERLY LOW LEVEL FLOW
ACROSS THE AREA WILL SUPPORT SCATTERED SHOWERS AND ISOLATED
THUNDERSTORMS ACROSS THE ISLAND THROUGH TONIGHT. LOW LEVEL FLOW
WILL BECOME SOUTHEASTERLY ON MONDAY AS THE INFLUENCES OF THE
CIRCULATION OF JOAQUIN DIMINISHES ACROSS THE REGION. THIS SHOULD
PRODUCE SLIGHTLY DRIER CONDITIONS ACROSS THE ISLAND ON MONDAY
WITH MAINLY ISOLATED AFTERNOON AND EVENING THUNDERSTORMS
EXPECTED.

ATLANTIC OCEAN...
HURRICANE JOAQUIN CONTINUES TO DOMINATE MUCH OF THE CONDITIONS
ACROSS THE SW N ATLC. PLEASE REFER TO THE SPECIAL FEATURES
SECTION FOR ADDITIONAL DETAILS ON JOAQUIN. AS OF 2100 UTC...A
COLD FRONT HAS BEEN ANALYZED FROM 31N80W TO 28N81W TO THE
EASTERN GULF. THE COMBINATION OF THE COLD FRONT AND AN UPPER LOW
NEAR 30N82W SUPPORTS SCATTERED SHOWERS AND ISOLATED
THUNDERSTORMS FROM 26N TO 30N W OF 77W. A PAIR OF SURFACE
TROUGHS ARE OVER THE SW N ATLC IN ASSOCIATION WITH THE BROAD
CIRCULATION OF JOAQUIN. THE FIRST TROUGH ENTERS OUR AREA OF
DISCUSSION NEAR 31N73W TO 28N70W. THE OTHER TROUGH EXTENDS FROM
29N63W TO 22N73W. NO DEEP CONVECTION IS NOTED WITH THE FIRST
TROUGH. ISOLATED MODERATE CONVECTION IS WITHIN 500 NM E OF THE
SECOND TROUGH. FARTHER EAST...A 1008 MB LOW IS CENTERED NEAR
27N53W WITH A SURFACE TROUGH EXTENDING FROM 31N58W THROUGH THE
LOW CENTER TO 26N44W. ISOLATED MODERATE CONVECTION IS WITHIN 50
NM OF THE LOW CENTER...AND WITHIN 250 NM OF THE TROUGH AXIS W OF
57W. A 1015 MB HIGH IS CENTERED NEAR 20N54W. A 1018 MB HIGH IS
CENTERED NEAR 25N30W. A TROPICAL WAVE AND SURFACE LOW ARE OVER
THE CENTRAL TROPICAL N ATLC. PLEASE REFER TO THE TROPICAL WAVES
SECTION FOR MORE DETAILS. OVER THE NEXT 24 HOURS CONVECTION WILL
CONTINUE BETWEEN THE DEPARTING CIRCULATION OF JOAQUIN...AND THE
UPPER LOW OVER FL AS THE LOW MOVES E THEN NE. CONVECTION WILL
ALSO REMAIN LIKELY NEAR THE SURFACE TROUGHS OVER THE ATLC TO THE
SE OF JOAQUIN.

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

$$
LATTO
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