[Tropical] Tropical Weather Discussion

[EMWIN Server]

AXNT20 KNHC 161806
TWDAT

TROPICAL WEATHER DISCUSSION
NWS NATIONAL HURRICANE CENTER MIAMI FL
205 PM 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 1200 UTC SURFACE ANALYSIS AND SATELLITE IMAGERY THROUGH
1715 UTC.

...TROPICAL WAVES...
TROPICAL WAVE AXIS EXTENDS FROM 11N34W TO 03N36W AND MOVES W
NEAR 10 KT. THE WAVE IS EMBEDDED WITHIN THE ITCZ AXIS AS WELL AS
IN A REGION OF HIGH TO MAXIMUM MOISTURE IN THE SSMI TOTAL
PRECIPITABLE WATER IMAGERY. SCATTERED MODERATE CONVECTION IS
FROM 03N-08N BETWEEN 32W-38W.

TROPICAL WAVE AXIS EXTENDS FROM 17N44W TO 09N50W AND MOVES W-NW
NEAR 5 KT. SSMI TOTAL PRECIPITABLE WATER IMAGERY SHOW THE WAVE
IS MOSTLY EMBEDDED WITHIN A MODERATE MOIST ENVIRONMENT. MOIST
UPPER-LEVEL SOUTHWESTERLY DIFFLUENT FLOW DEPICTED IN WATER VAPOR
IMAGERY IS SUPPORTING SCATTERED SHOWERS AND ISOLATED TSTMS ARE
FROM 10N-16N BETWEEN 40W-54W.

TROPICAL WAVE AXIS PREVIOUSLY OVER CENTRAL AMERICA HAS MOVED TO
THE EAST PACIFIC. ITS AXIS EXTENDS FROM 14N90W TO 08N87W AND IS
MOVING W NEAR 15-20 KT. SMI TOTAL PRECIPITABLE WATER IMAGERY
SHOW THE WAVE IS EMBEDDED WITHIN A VERY MOIST ENVIRONMENT.
MIDDLE-LEVEL DIFFLUENCE IS SUPPORTING SCATTERED MODERATE
CONVECTION FROM 09N-13N BETWEEN 87W-92W.

...ITCZ/MONSOON TROUGH...
THE MONSOON TROUGH EXTENDS FROM THE AFRICAN COAST NEAR 09N13W TO
06N17W TO 06N21W. THE INTERTROPICAL CONVERGENCE ZONE AXIS
EXTENDS FROM 06N21W TO 08N32W...THEN CONTINUES WEST OF A TROPICAL
WAVE NEAR 06N38W TO 08N47W...THEN CONTINUES WEST OF A SECOND
TROPICAL WAVE NEAR 09N52W TO GUYANA NEAR 07N59W. ASIDE FROM
CONVECTION ASSOCIATED WITH THE TROPICAL WAVES...SCATTERED
MODERATE CONVECTION IS FROM 04N-10N EAST OF 18W. SIMILAR
CONVECTION IS WITHIN 200 NM NORTH AND 100 NM SOUTH OF THE ITCZ
AXIS BETWEEN 38W-48W.

...DISCUSSION...

GULF OF MEXICO...
A MIDDLE TO UPPER LEVEL ANTICYCLONIC CIRCULATION IS CENTERED
OVER THE GULF NEAR 24N90W AND 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 10 KT
ACROSS THE BASIN. A WEAK SURFACE TROUGH IS ON THE NE GULF
EXTENDING FROM 29N86W TO 26N84W WITH NO CONVECTION ASSOCIATED
WITH IT. AN UPPER-LEVEL TROUGH EXTENDING FROM NORTHERN MICHIGAN
LAKE SW TO THE CENTRAL ROCKIES IS SUPPORTING A FRONTAL SYSTEM
THAT ENTERS THE FAR NW GULF AS A COLD FRONT. THE COLD FRONT
EXTENDS FROM SW LOUISIANA NEAR 29N93W SW TO SOUTHERN TEXAS NEAR
27N97W. ISOLATED SHOWERS ARE SHOWN IN RADAR IMAGERY N OF 26N W
OF 91W. THE FRONT WILL CONTINUE TO DRIFT E-SE THROUGH THURSDAY
NIGHT AND THEN IS FORECAST TO BECOME STATIONARY ACROSS THE NE
AND AND NW GULF.

CARIBBEAN SEA...
A MIDDLE TO UPPER LEVEL TROUGH AXIS EXTENDS FROM THE SW NORTH
ATLC REGION TO HISPANIOLA TO THE SOUTHERN-CENTRAL BASIN. THIS
MIDDLE TO UPPER LEVEL FEATURE SUPPORTS A SURFACE TROUGH THAT AT
1500 UTC EXTENDS FROM 24N69W TO THE WINDWARD PASSAGE NEAR 19N73W
TO 17N77W. SCATTERED MODERATE CONVECTION IS WITHIN 50 NM EITHER
SIDE OF THE AXIS FROM 16N-19N. WEST OF THE MIDDLE TO UPPER LEVEL
TROUGH AXIS...NORTHERLY FLOW FROM THE BROAD RIDGE OVER THE GULF
IS ADVECTING DRY AIR TO THE NW GULF N OF 15N W OF 79W WHICH IS
SUPPRESSING ANY SIGNIFICANT CONVECTION AT THIS TIME. FURTHER
EAST...DIFFLUENT FLOW ALOFT IS SUPPORTING SCATTERED SHOWERS AND
ISOLATED TSTMS OVER THE CENTRAL BASIN S OF 15N BETWEEN 69W-75W.
SIMILAR CONVECTION IS OVER THE SOUTHERN CARIBBEAN S OF 15N WHICH
IS ASSOCIATED WITH THE MONSOON TROUGH AXIS THAT EXTENDS FROM
NORTHERN COSTA RICA TO NORTHERN COLOMBIA.

A SURFACE TROUGH IS FORECAST TO MOVE ACROSS THE LEEWARD ISLANDS
EARLY ON FRIDAY WHICH IS EXPECTED TO DISSIPATE IN THE EVENING
HOURS. ISOLATED SHOWERS IS LIKELY FOR THE NE BASIN.

HISPANIOLA...
A MIDDLE TO UPPER LEVEL TROUGH AXIS EXTENDS FROM THE SW NORTH
ATLC REGION TO HISPANIOLA TO THE SOUTHERN-CENTRAL CARIBBEAN.
THIS MIDDLE TO UPPER LEVEL FEATURE SUPPORTS A SURFACE TROUGH
THAT AT 1500 UTC EXTENDS FROM 24N69W TO THE WINDWARD PASSAGE
NEAR 19N73W TO 17N77W. CURRENTLY...THIS INSTABILITY IN THE
ATMOSPHERE IS PRODUCING ISOLATED SHOWERS ACROSS THE ISLAND.
HOWEVER...AS THE THE MIDDLE TO UPPER LEVEL TROUGHING CONTINUES
TO DRIFT EASTWARD CONVECTIVE ACTIVITY MAY DEVELOP LATER THIS
AFTERNOON. SCATTERED MODERATE CONVECTION IS SW OF THE SOUTHERN
COASTLINE OF HAITI WITHIN 50 NM EITHER SIDE OF THE SURFACE
TROUGH AXIS FROM 16N-19N. SHOWER AND TSTMS ACTIVITY IS
EXPECTED THROUGH FRIDAY.

ATLANTIC OCEAN...
A MIDDLE TO UPPER LEVEL TROUGH AXIS IN THE SW NORTH ATLC NEAR
70W IS SUPPORTING A SURFACE TROUGH THAT EXTENDS FROM 22N67W TO
27N66W TO 29N69W. SCATTERED MODERATE CONVECTION AND TSTMS ARE
WITHIN 350 NM EAST OF THE AXIS. IT ALSO SUPPORTS ANOTHER SURFACE
TROUGH THAT EXTENDS FROM 24N69W TO THE WINDWARD PASSAGE NEAR
19N73W TO 17N77W. SCATTERED MODERATE CONVECTION AND TSTMS ARE
FROM 20N-25N BETWEEN 68W-73W...INCLUDING THE SOUTHERN BAHAMAS. A
WEAK SURFACE TROUGH IS NE OF THE LEEWARD ISLANDS EXTENDING FROM
21N59W TO 16N56W WITH NO CONVECTION ASSOCIATED WITH IT.
OTHERWISE...AN UPPER-LEVEL TROUGH IN THE CENTRAL N ATLC SUPPORTS
A FRONTAL SYSTEM THAT ENTERS THE AREA OF DISCUSSION AS A COLD
FRONT NEAR 30N34W SW TO 27N45W WHERE IT TRANSITIONS TO A
STATIONARY FRONT TO 30N55W. SCATTERED SHOWERS ARE N OF 26N
BETWEEN 32W-53W.

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

$$
NR


This weather bulletin was brought to you by:
www.nashvilleweather.net