[Tropical] Tropical Weather Discussion

[EMWIN Server]

AXNT20 KNHC 260006
TWDAT

TROPICAL WEATHER DISCUSSION
NWS NATIONAL HURRICANE CENTER MIAMI FL
805 PM EDT SUN AUG 25 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 1800 UTC SURFACE ANALYSIS AND SATELLITE IMAGERY THROUGH
2315 UTC.

...SPECIAL FEATURES...
TROPICAL STORM FERNAND FORMED IN THE SOUTHWESTERN BAY OF
CAMPECHE NEAR 2230 UTC. ITS CENTER IS LOCATED NEAR 19.1N 95.7W
OR 24 NM EAST OF VERACRUZ MEXICO WITH A MINIMUM CENTRAL PRESSURE
OF 1003 MB. THE STORM IS MOVING WEST AT 10 KT AND MAXIMUM
SUSTAINED WINDS ARE 40 KT WITH HIGHER GUSTS. A CLUSTER OF
MODERATE/ISOLATED STRONG CONVECTION IS FROM 18N-21N. SCATTERED
MODERATE CONVECTION AND ISOLATED TSTMS ARE ELSEWHERE S OF 26N W
OF 93W. A WESTWARD TO WEST-NORTHWESTWARD MOTION WITH SOME
DECREASE IN FORWARD SPEED IS EXPECTED OVER THE NEXT DAY OR TWO.
ON THE FORECAST TRACK...THE CENTER SHOULD CROSS THE COAST OF
MEXICO IN THE WARNING AREA BY EARLY MONDAY. SEE LATEST NHC
FORECAST/ADVISORY UNDER AWIPS/WMO HEADERS MIATCMAT1/WTNT21 KNHC
FOR MORE DETAILS.

...TROPICAL WAVES...
TROPICAL WAVE AXIS EXTENDS FROM 22N34W TO 09N36W MOVING W NEAR
10 KT. THE WAVE IS EMBEDDED IN A MODERATE MOIST ENVIRONMENT N OF
14N AND IN THE HIGH MOIST ENVIRONMENT OF THE MONSOON TROUGH S OF
THAT LATITUDE. AN UPPER LOW CENTERED NW OF THE NORTHERN WAVE
AXIS IS ENHANCING SCATTERED MODERATE CONVECTION FROM 21N-26N
BETWEEN 29W-36W. ISOLATED SHOWERS ARE FROM 09N-16N BETWEEN 31W-
41W.

TROPICAL WAVE ENTERING THE CENTRAL CARIBBEAN WITH AXIS EXTENDING
FROM 16N68W TO INLAND OVER VENEZUELA NEAR 08N69W MOVING W NEAR
10 KT. THE WAVE IS EMBEDDED WITHIN AN AREA OF HIGH MOISTURE THAT
COVERS THE CENTRAL CARIBBEAN FROM 13N-16N. SCATTERED MODERATE
CONVECTION AND ISOLATED TSTMS COINCIDING WITH THIS AREA ARE FROM
14N-18N BETWEEN 66W-78W.

...ITCZ/MONSOON TROUGH...
THE MONSOON TROUGH EXTENDS ACROSS AFRICA INTO THE E TROPICAL
ATLC NEAR 13N16W AND CONTINUES ALONG 08N23W 13N35W TO 09N45W.
THE ITCZ BEGINS NEAR 09N45W AND CONTINUES ALONG 7N51W TO
VENEZUELA NEAR 08N61W. A 1008 MB LOW IS CENTERED NEAR 11N48W
WITH SCATTERED MODERATE CONVECTION FROM 10N-12N BETWEEN 48W-51W.
BESIDES THE CONVECTION ASSOCIATED WITH THIS LOW AND THE
AFOREMENTIONED TROPICAL WAVE...SCATTERED MODERATE CONVECTION IS
WITHIN 200 NM EITHER SIDE OF THE MONSOON TROUGH AXIS EAST OF 21W
AS WELL AS SOUTH OF THE AXIS BETWEEN 22W-29W. SIMILAR CONVECTION
IS FROM 07N-13N BETWEEN 42W-48W.

...DISCUSSION...

GULF OF MEXICO...
TROPICAL STORM FERNAND FORMED IN THE SOUTHWESTERN BAY OF
CAMPECHE NEAR 2230 UTC. ITS CENTER IS LOCATED NEAR 19.1N 95.7W
OR 24 NM EAST OF VERACRUZ MEXICO WITH A MINIMUM CENTRAL PRESSURE
OF 1003 MB. MAXIMUM SUSTAINED WINDS ARE 40 KT WITH HIGHER GUSTS.
A CLUSTER OF MODERATE/ISOLATED STRONG CONVECTION IS FROM 18N-
21N. SCATTERED MODERATE CONVECTION AND ISOLATED TSTMS ARE
ELSEWHERE S OF 26N W OF 93W. A NARROW UPPER LEVEL TROUGH
OFFSHORE THE EASTERN CONUS N OF 30N SUPPORTS A COLD FRONT OVER
THE SW N ATLC THAT MOVES ACROSS CENTRAL FLORIDA INTO THE NE GULF
NEAR 28N82W. FROM THERE THE COLD FRONT TRANSITIONS INTO A
STATIONARY FRONT ALONG 28N86W TO SE LOUISIANA NEAR 29N89W.
NUMEROUS MODERATE CONVECTION AND ISOLATED TSTMS ARE S OF THE
FRONTAL BOUNDARY BETWEEN 85W-95W. SCATTERED SHOWERS ARE WITHIN
130 NM N OF THE STATIONARY FRONT. SIMILAR CONVECTION IS OCCURRING
IN THE SE GULF FROM 23N-27N E OF 88W.

THE CENTER OF TROPICAL STORM FERNAND IS EXPECTED TO CROSS THE
COAST OF MEXICO IN THE WARNING AREA BY EARLY MONDAY. THE COLD
FRONT WILL WEAKEN THROUGH MON BEFORE DISSIPATING TUE.

CARIBBEAN SEA...
MOISTURE IS BEING ADVECTED ACROSS CUBA BY NORTHEASTERLY WIND
FLOW AROUND AN UPPER LEVEL RIDGE CENTERED IN THE GULF. THIS
MOISTURE ALONG WITH MIDDLE LEVEL DIFFLUENCE IS SUPPORTING
SCATTERED MODERATE CONVECTION AND TSTMS WITHIN 90 NM OF THE
SOUTHERN COASTLINE OF CUBA. BESIDES THAT...FAIR WEATHER IS
ACROSS THE WESTERN BASIN W OF 79W BEING SUPPORTED BY DRY AIR IN
THE LOWER AND MIDDLE LEVELS. A TROPICAL WAVE IS STARTING TO MOVE
ACROSS THE CENTRAL CARIBBEAN WITH AXIS EXTENDING FROM 16N68W TO
INLAND OVER VENEZUELA NEAR 08N69W. THE WAVE IS EMBEDDED WITHIN
AN AREA OF HIGH MOISTURE THAT COVERS THE CENTRAL CARIBBEAN FROM
13N-16N. SCATTERED MODERATE CONVECTION AND ISOLATED TSTMS
COINCIDING WITH THIS AREA ARE FROM 14N-18N BETWEEN 66W-78W.
SCATTERED SHOWERS ARE S OF 11N E OF 79W ASSOCIATED WITH THE
MONSOON TROUGH AXIS WHICH MOVES ALONG PANAMA TO NORTHERN
COLOMBIA. RAINSHOWERS HAS BEEN REPORTED IN THE LEEWARD ISLANDS
ASSOCIATED WITH A PATCH OF LOW LEVEL MOISTURE OVER THAT REGION.

MODERATE TO FRESH TRADE WINDS ARE EXPECTED IN THE W AND CENTRAL
CARIBBEAN THROUGH MON THEN WILL DIMINISH TUE AND WED. CARIBBEAN
TROPICAL WAVE WILL REACH SW CARIBBEAN MON NIGHT THROUGH TUE.

HISPANIOLA...
CURRENTLY VERY DRY AIR IS IN THE LOWER LEVELS ACROSS THE ISLAND
SUPPORTING FAIR WEATHER. HOWEVER...A TROPICAL WAVE IS STARTING
TO MOVE ACROSS THE CENTRAL CARIBBEAN AND IS GENERATING SCATTERED
MODERATE CONVECTION AND ISOLATED TSTMS FROM 14N TO JUST SOUTH OF
THE ISLAND BETWEEN 66W-78W. UPPER LEVEL SOUTHEASTERLY FLOW
AROUND A RIDGE MAY ADVECT SOME OF THIS MOISTURE ACROSS THE
ISLAND WHICH SUPPORTED BY AN UPPER LEVEL DIFFLUENCE PATTERN
MIGHT ENHANCE SHOWERS AND THUNDERSTORMS THIS EVENING. THE
TROPICAL WAVE WILL MOVE INTO THE W CARIBBEAN AWAY FROM
HISPANIOLA MON REDUCING THE CHANCE OF SHOWERS/THUNDERSTORMS BY
TUE.

ATLANTIC OCEAN...
A NARROW UPPER LEVEL TROUGH OFFSHORE THE EASTERN CONUS N OF 30N
SUPPORTS A COLD FRONT OVER THE SW N ATLC FROM 30N67W TO 28N76W
28N80W AND ACROSS CENTRAL FLORIDA. THIS FRONTAL BOUNDARY IS
SUPPORTING SCATTERED MODERATE CONVECTION N OF 27N W OF 61W.
OTHERWISE...BESIDES THE TROPICAL WAVE AND THE LOW ALREADY
DISCUSSED...FAIR WEATHER DOMINATES ACROSS THE REST OF THE BASIN.

THE FRONT WILL BECOME STATIONARY WHILE GRADUALLY DISSIPATING
FROM BERMUDA TO CENTRAL FLORIDA TONIGHT AND MON. SURFACE RIDGE
WILL THEN RE-ESTABLISH ALONG 29N/30N TUE THROUGH THU.

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

$$
NR


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