[Tropical] Tropical Weather Discussion

[EMWIN Server]

AXNT20 KNHC 160551
TWDAT

TROPICAL WEATHER DISCUSSION
NWS NATIONAL HURRICANE CENTER MIAMI FL
205 AM EDT WED OCT 16 2013

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
0515 UTC.

...TROPICAL WAVES...
TROPICAL WAVE EXTENDS FROM 06N33W TO 12N29W MOVING W AT 10-15
KT. THE WAVE REMAINS LOW AMPLITUDE AND EMBEDDED WITHIN THE ITCZ
AXIS WITH SURFACE TO 700 MB TROUGHING NOTED BETWEEN 28W-37W.
WIDELY SCATTERED MODERATE CONVECTION IS FROM 03N-10N BETWEEN 24W-
38W.

TROPICAL WAVE EXTENDS FROM 08N50W TO 17N43W MOVING W AT 5-10 KT.
THE WAVE COINCIDES WITH SURFACE TO 700 MB TROUGHING WITH LOW-
LEVEL MOISTURE CONVERGENCE IN THE VICINITY OF THE WAVE AXIS. IN
ADDITION...MOIST SOUTHWESTERLY DIFFLUENT UPPER LEVEL FLOW IS
HELPING TO SUSTAIN WIDELY SCATTERED MODERATE CONVECTION WITHIN
120 NM EITHER SIDE OF A LINE FROM 10N51W TO 18N40W.

TROPICAL WAVE EXTENDS FROM 11N87W TO 18N85W MOVING W AT 10 KT.
THE WAVE LIES BENEATH THE SOUTHEASTERN PERIPHERY OF AN UPPER
LEVEL ANTICYCLONIC CIRCULATION CENTERED OVER THE GULF OF MEXICO
NEAR 23N91W PROVIDING A MARGINAL DIFFLUENT ENVIRONMENT OVER
CENTRAL AMERICA THIS EVENING. ISOLATED MODERATE CONVECTION IS
FROM 07N-16N BETWEEN 84W-89W.

...ITCZ/MONSOON TROUGH...
THE MONSOON TROUGH EXTENDS FROM THE AFRICAN COAST NEAR 12N17W TO
11N19W. THE INTERTROPICAL CONVERGENCE ZONE AXIS EXTENDS FROM
11N19W TO 07N32W TO 06N41W TO 09N49W TO 08N60W. ASIDE FROM
CONVECTION ASSOCIATED WITH THE TROPICAL WAVES...ISOLATED
MODERATE TO STRONG CONVECTION IS FROM 06N-11N BETWEEN 11W-15W.

...DISCUSSION...

GULF OF MEXICO...
A MIDDLE TO UPPER LEVEL ANTICYCLONIC CIRCULATION IS CENTERED
OVER THE CENTRAL GULF NEAR 23N91W THAT IS PROVIDING THE BASIN
WITH GENERALLY DRY AND STABLE FLOW ALOFT. THIS STABILITY
REFLECTS TO THE SURFACE AS A RIDGE REMAINS IN PLACE EXTENDING SW
FROM THE SE CONUS WITH LIGHT ANTICYCLONIC WINDS IN THE RANGE OF
5 TO 15 KT FORECAST ACROSS THE BASIN THROUGH THE OVERNIGHT
HOURS. THE SURFACE RIDGING IS EXPECTED TO BE COMPROMISED BY A
COLD FRONT MOVING CLOSER TO THE TEXAS GULF COAST THIS EVENING
CURRENTLY ANALYZED FROM EAST TEXAS TO THE EXTREME NORTHERN
MEXICO. THE FRONT IS FORECAST TO EMERGE INTO THE NW GULF WATERS
BY LATE WEDNESDAY MORNING INTO THE EARLY AFTERNOON HOURS WITH
WINDS WEST OF THE FRONT SHIFTING NORTH-NORTHEASTERLY.

CARIBBEAN SEA...
AN UPPER LEVEL TROUGH AXIS IS NOTED ON WATER VAPOR IMAGERY
EXTENDING FROM THE SW NORTH ATLC REGION OVER HISPANIOLA NEAR
19N72W TO 12N80W. WEST OF THE TROUGH AXIS...NORTHERLY UPPER
LEVEL FLOW DOMINATES WITH DRY AIR PUSHING AS FAR SOUTH AS 13N
SUPPRESSING ANY SIGNIFICANT CONVECTION AT THIS TIME. A TROPICAL
WAVE HOWEVER IS ALONG 86W PRIMARILY INLAND ACROSS PORTIONS OF
CENTRAL AMERICA CONTINUING TO GENERATE ISOLATED SHOWERS AND
TSTMS ACROSS HONDURAS...NICARAGUA...AND COSTA RICA THIS EVENING.
THE WAVE IS ANTICIPATED TO MOVE INTO THE EAST PACIFIC REGION
WITHIN THE NEXT 12 TO 24 HOURS. OTHERWISE...MUCH OF THE NW
CARIBBEAN IS UNDER FAIR SKIES AND CONDITIONS DUE TO THE DRY AIR
ALOFT. EAST OF THE TROUGH AXIS...MAXIMUM MIDDLE TO UPPER LEVEL
LIFTING DYNAMICS ARE GENERATING WIDELY SCATTERED SHOWERS AND
ISOLATED TSTMS BETWEEN 67W-78W...WITH THE STRONG CONVECTION
OCCURRING ACROSS EASTERN CUBA...PORTIONS OF HISPANIOLA...AND THE
WINDWARD PASSAGE REGION. THE UPPER LEVEL TROUGH IS FORECAST TO
SLOWLY DRIFT EASTWARD LEAVING MUCH OF THE EASTERN CARIBBEAN E OF
75W WITHIN THE DIFFLUENCE ALOFT THROUGH THE WEEKEND AHEAD.
LASTLY...THE EASTERN CARIBBEAN IS FAIRLY TRANQUIL THIS EVENING
WITH ONLY A FEW ISOLATED LOW-TOPPED SHOWERS OCCURRING S OF 16N E
OF 65W DUE TO THE APPROACH OF A SURFACE TROUGH EAST OF BARBADOS
NEAR 13N59W TO 21N54W.

HISPANIOLA...
CURRENTLY THE ISLAND FALLS WITHIN MAXIMUM UPPER LEVEL DIFFLUENCE
EAST OF AN UPPER LEVEL TROUGH AXIS EXTENDING FROM 22N72W TO
14N77W. MOISTURE ALREADY IN PLACE OVER THE REGION CONTINUES TO
LIFT GENERATING CLOUDINESS AND WIDELY SCATTERED SHOWERS AND
ISOLATED TSTMS MAINLY N OF 19N BETWEEN 66W-77W INCLUDING BOTH
THE MONA AND WINDWARD PASSAGES...AND ADJACENT COASTAL WATERS.
THE UPPER LEVEL TROUGHING IS EXPECTED TO DRIFT VERY SLOWLY EAST
THROUGH THE UPCOMING WEEKEND PROVIDING THE INCREASED PROBABILITY
OF SHOWER AND TSTM ACTIVITY THROUGH SUNDAY.

ATLANTIC OCEAN...
A MIDDLE TO UPPER LEVEL TROUGH AXIS IS NOTED ON WATER VAPOR
IMAGERY AND EXTENDS INTO THE DISCUSSION AREA NEAR 32N70W TO
18N70W THEN TO THE BASE OVER THE SW CARIBBEAN SEA. THE TROUGHING
IS SUPPORTING AN OVERALL WEAK PRESSURE GRADIENT AND OVERALL
LOWER PRESSURE AREA W OF 58W. A 1009 MB LOW IS CENTERED NEAR
33N72W AND EXTENDS SURFACE TROUGHING SOUTHWARD TO 29N75W.
ANOTHER SURFACE TROUGH IS ANALYZED TO THE SOUTH FROM CENTRAL
CUBA NEAR 23N78W TO 28N70W AND IS LARGELY THE SURFACE FEATURE
ASSOCIATED WITH THE UPPER LEVEL TROUGH AT THIS TIME. WHILE LOW-
LEVEL MOISTURE CONVERGENCE IS MAXIMIZED ALONG AND SOUTH OF THE
TROUGH AXIS...MIDDLE TO UPPER LEVEL DIFFLUENT IS PLAYING A
LARGER ROLE IN GENERATING SCATTERED SHOWERS AND WIDELY SCATTERED
TSTMS FROM 19N-22N BETWEEN 66W-77W. WHILE THIS REMAINS THE MAIN
AREA OF CONVECTION OCCURRING...MOISTURE CONTINUES TO ADVECT
NORTHWARD ON THE EASTERN PERIPHERY OF THE TROUGH WITH ISOLATED
SHOWERS OCCURRING ELSEWHERE FROM 22N-32N BETWEEN 60W-69W.
FARTHER EAST...WATER VAPOR IMAGERY INDICATES A BROAD UPPER LEVEL
LOW CENTERED OVER THE CENTRAL NORTH ATLC THAT SUPPORTS A
STATIONARY FRONT ANALYZED INTO THE DISCUSSION AREA NEAR 32N34W.
THE FRONT CONTINUES W-SW ALONG 29N40W TO 28N50W TO 30N60W.
ISOLATED SHOWERS AND TSTMS ARE OCCURRING WITHIN 120 NM EITHER
SIDE OF THE BOUNDARY. TO THE SOUTH OF THE STATIONARY FRONT...AN
UPPER LEVEL TROUGH IS NOTED ON WATER VAPOR IMAGERY IN THE
VICINITY OF 17N56W. A SURFACE TROUGH AXIS RESULTS AT THE SURFACE
EXTENDING FROM 13N59W TO 21N54W WITH ISOLATED SHOWERS AND TSTMS
OCCURRING FROM 14N-19N BETWEEN 48W-55W. FINALLY...THE REMAINDER
OF THE CENTRAL AND EASTERN ATLC ARE UNDER THE INFLUENCE OF A
SURFACE RIDGE ANCHORED BY A 1025 MB HIGH CENTERED NEAR THE
MADEIRA ISLANDS NEAR 34N17W. THE RIDGE AXIS EXTENDS FROM THE
HIGH SOUTHWESTWARD TO 24N45W.

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

$$
HUFFMAN


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