[Tropical] Tropical Weather Discussion

[EMWIN Server]

AXNT20 KNHC 161045
TWDAT

TROPICAL WEATHER DISCUSSION
NWS NATIONAL HURRICANE CENTER MIAMI FL
805 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 0600 UTC SURFACE ANALYSIS AND SATELLITE IMAGERY THROUGH
1015 UTC.

...TROPICAL WAVES...
TROPICAL WAVE EXTENDS FROM 05N35W TO 12N32W 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 30W-39W.
SCATTERED MODERATE CONVECTION IS FROM 03N-10N BETWEEN 31W-36W.

TROPICAL WAVE EXTENDS FROM 08N49W TO 17N44W 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 SCATTERED MODERATE CONVECTION FROM 14N-18N
BETWEEN 39W-45W...AND WITHIN 90 NM EITHER SIDE OF A LINE FROM
09N55W TO 13N48W.

TROPICAL WAVE EXTENDS FROM 12N86W TO 16N87W MOVING W AT 5 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 MORNING. ISOLATED MODERATE CONVECTION IS
FROM 11N-17N BETWEEN 87W-90W.

...ITCZ/MONSOON TROUGH...
THE MONSOON TROUGH EXTENDS FROM THE AFRICAN COAST NEAR 09N13W TO
07N20W. THE INTERTROPICAL CONVERGENCE ZONE AXIS EXTENDS FROM
07N20W TO 09N29W TO 07N35W TO 06N42W TO 08N49W TO 06N57W. ASIDE
FROM CONVECTION ASSOCIATED WITH THE TROPICAL WAVES...ISOLATED
MODERATE CONVECTION IS FROM 05N-11N BETWEEN 10W-17W...AND FROM
05N-10N BETWEEN 38W-47W.

...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 MORNING HOURS.
THE SURFACE RIDGING IS EXPECTED TO BE COMPROMISED BY A COLD
FRONT MOVING CLOSER TO THE TEXAS GULF COAST THIS MORNING
CURRENTLY ANALYZED FROM EAST TEXAS NEAR 32N94W TO NORTH-CENTRAL
MEXICO NEAR 28N102W. 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
19N71W TO 12N79W. WEST OF THE TROUGH AXIS...NORTHERLY UPPER
LEVEL FLOW DOMINATES WITH DRY AIR PUSHING AS FAR SOUTH AS 11N
SUPPRESSING ANY SIGNIFICANT CONVECTION AT THIS TIME. A TROPICAL
WAVE HOWEVER IS ALONG 87W PRIMARILY INLAND ACROSS PORTIONS OF
CENTRAL AMERICA CONTINUING TO GENERATE ISOLATED SHOWERS AND
TSTMS ACROSS EL SALVADOR AND THE WATERS OF THE EAST PACIFIC
REGION THIS MORNING. THE WAVE IS ANTICIPATED TO MOVE INTO THE
EAST PACIFIC REGION WITHIN THE NEXT 12 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 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 MORNING.

HISPANIOLA...
CURRENTLY THE ISLAND FALLS WITHIN MAXIMUM UPPER LEVEL DIFFLUENCE
EAST OF AN UPPER LEVEL TROUGH AXIS EXTENDING FROM 24N70W TO
17N74W. MOISTURE ALREADY IN PLACE OVER THE REGION CONTINUES TO
LIFT GENERATING CLOUDINESS AND WIDELY SCATTERED SHOWERS AND
ISOLATED TSTMS MAINLY N OF 17N 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 32N69W TO
18N69W 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 56W. A 1011 MB LOW IS CENTERED NEAR
33N72W AND EXTENDS SURFACE TROUGHING SOUTHWARD TO 29N74W.
ANOTHER SURFACE TROUGH IS ANALYZED TO THE SOUTH FROM CENTRAL
CUBA NEAR 22N77W TO 27N71W 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 17N-25N BETWEEN 65W-77W. WHILE THIS REMAINS THE MAIN
AREA OF CONVECTION...MOISTURE CONTINUES TO ADVECT NORTHWARD ON
THE EASTERN PERIPHERY OF THE TROUGH WITH ISOLATED SHOWERS
OCCURRING ELSEWHERE FROM 25N-32N BETWEEN 60W-70W. 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 32N33W. THE FRONT
CONTINUES W-SW ALONG 30N40W TO 28N47W TO 30N64W. ISOLATED
SHOWERS AND TSTMS ARE OCCURRING WITHIN 150 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
19N55W. A SURFACE TROUGH AXIS RESULTS AT THE SURFACE EXTENDING
FROM 13N59W TO 20N55W WITH POSSIBLE ISOLATED SHOWERS FROM 15N-
21N BETWEEN 49W-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 NE OF THE MADEIRA ISLANDS NEAR
35N14W. THE RIDGE AXIS EXTENDS FROM THE HIGH SOUTHWESTWARD TO
25N40W.

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

$$
HUFFMAN


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