[Tropical] Tropical Weather Discussion

[EMWIN Server]

AXNT20 KNHC 121140
TWDAT

TROPICAL WEATHER DISCUSSION
NWS NATIONAL HURRICANE CENTER MIAMI FL
705 AM EST THU DEC 12 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
1115 UTC.

...ITCZ/MONSOON TROUGH...
THE MONSOON TROUGH AXIS EXTENDS ACROSS AFRICA INTO THE EAST
TROPICAL ATLC NEAR 05N09W TO 04N16W. THE ITCZ AXIS EXTENDS FROM
04N16W TO 04N34W TO 06N50W. SCATTERED MODERATE CONVECTION AND
TSTMS ARE FROM 02N-07N BETWEEN E OF 20W. SCATTERED MODERATE
CONVECTION IS WITHIN AN AREA ENCLOSED BY A LINE FROM 18N16W TO
06N28W AND A LINE EXTENDING FROM 20N23W TO 08N43W.

...DISCUSSION...

GULF OF MEXICO...
A BROAD MIDDLE-LEVEL TROUGH WITH AXIS EXTENDING FROM THE NE
U.S.A TO THE CENTRAL GULF SUPPORTS A STATIONARY FRONT ANALYZED
FROM WESTERN-SOUTHERN FLORIDA NEAR 26N81W SW TO 23N90W TO THE
BAY OF CAMPECHE NEAR 18N94W. A 1040 MB HIGH CENTERED IN THE
MIDDLE MISSISSIPPI VALLEY NEAR 38N91W EXTENDS A RIDGE AXIS INTO
THE GULF AND PROVIDES NORTHEASTERLY WIND FLOW UP TO 25 KT ACROSS
THE ENTIRE BASIN. EXCEPT FOR THE SW BASIN S OF 24N AND THE SE
GULF S OF 25N...SSMI TPW IMAGERY DEPICT DRY AIR ACROSS THE BASIN
AT THE LOWER LEVELS WHICH IS SUSTAINING FAIR WEATHER. ON THE SW
GULF...DRY AIR SUBSIDENCE FROM A MIDDLE-LEVEL ANTICYCLONIC
CIRCULATION CENTERED NEAR 20N94W SUPPORTS FAIR WEATHER. ON THE
SE GULF...A SURFACE TROUGH OVER THE FAR NW CARIBBEAN SEA ADVECTS
VERY MOIST AIR TO THE REGION TO SUPPORT SCATTERED SHOWERS OVER
THE FLORIDA STRAITS AND THE YUCATAN CHANNEL. HIGH PRESSURE AND
NORTHEASTERLY WIND FLOW ARE EXPECTED TO CONTINUE ACROSS THE GULF
THROUGHOUT FRI MORNING. THE FRONTAL BOUNDARY IS FORECAST TO MOVE
OUT OF THE GULF WATERS BY EARLY FRI. A COLD FRONT IS FORECAST TO
EMERGE ACROSS THE NW GULF SAT AFTERNOON.

CARIBBEAN SEA...
LOW-LEVEL MOISTURE CONVERGENCE IS ALONG THE COASTLINE FROM THE
YUCATAN PENINSULA TO CENTRAL PANAMA TO SUPPORT SCATTERED
MODERATE CONVECTION WITHIN 170 NM FROM THE COAST OF NICARAGUA TO
CENTRAL PANAMA. SIMILAR CONVECTION IS S OF 22N W OF 82W
ASSOCIATED WITH THE REMNANTS OF A SURFACE TROUGH THAT AT 0900
UTC EXTENDS FROM 22N86W TO S OF BELIZE NEAR 15N88W. OVER THE
CENTRAL BASIN...AT THE LOWER LEVELS AN INVERTED TROUGH SUPPORTS
A SURFACE TROUGH FROM 24N71W ON THE ATLC TO CENTRAL HISPANIOLA
NEAR 19N71W TO 16N71W. THE SURFACE TROUGH IS GENERATING ISOLATED
SHOWERS AND TSTMS OVER SOUTHERN ADJACENT WATERS N OF 15N BETWEEN
67W-73W. ALOFT AND ACROSS THE REMAINDER BASIN WESTERLY WIND FLOW
AND DRY AIR SUBSIDENCE DOMINATE AND SUPPORT FAIR WEATHER.
OTHERWISE...A RELATIVELY TIGHT PRESSURE GRADIENT OVER THE
CENTRAL-EASTERN BASIN SUPPORTS 20-25 KT WINDS EXPECTED TO
PERSIST THROUGHOUT SAT MORNING. RAINSHOWERS ASSOCIATED WITH THE
REMNANTS OF THE SURFACE TROUGH ARE EXPECTED THROUGHOUT THU NIGHT.

HISPANIOLA...
AN INVERTED TROUGH AT THE LOWER LEVELS SUPPORTS A SURFACE TROUGH
FROM 24N71W ON THE ATLC TO CENTRAL HISPANIOLA NEAR 19N71W TO
16N71W. THE SURFACE TROUGH IS GENERATING ISOLATED SHOWERS AND
TSTMS OVER SOUTHERN ADJACENT WATERS N OF 15N BETWEEN 67W-73W.
SHOWERS ASSOCIATED WITH THIS TROUGH WILL CONTINUE THROUGHOUT THU
NIGHT.

ATLANTIC OCEAN...
A BROAD MIDDLE-LEVEL TROUGH WITH AXIS EXTENDING FROM THE NE
U.S.A CONUS TO THE CENTRAL GULF SUPPORTS A STATIONARY FRONT
ANALYZED FROM 30N70W SW TO THE EASTERN-CENTRAL FLORIDA COAST
NEAR 26N80W. VERY DRY AIR ACROSS THE SW NORTH ATLC AND CENTRAL
ATLC HINDERS CONVECTION AT THE TIME. FARTHER EAST OVER THE
CENTRAL ATLC...A 1026 MB HIGH IS NEAR 28N49W WHICH IS EXPECTED
TO DRIFT E OVER THE NEXT 24 HOURS MAINTAINING FAIR WEATHER
CONDITIONS. A WEAK SURFACE TROUGH IS SW OF THE RIDGE EXTENDING
FROM 23N60W TO 19N64W WITH NO CONVECTION ASSOCIATED WITH IT AT
THE TIME. A MIDDLE TO UPPER LEVEL NARROW TROUGH ALONG THE
EASTERN ATLC SUPPORTS A FRONTAL SYSTEM ANALYZED AS A DISSIPATING
COLD FRONT FROM 30N14W TO 25N16W TO 20N21W. SCATTERED SHOWERS
AND TSTMS ASSOCIATED WITH THIS FRONTAL SYSTEM ARE N OF 23N
BETWEEN 13W-19W.

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

$$
NR


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