[Tropical] Tropical Weather Discussion

[EMWIN Server]

AXNT20 KNHC 222357
TWDAT

TROPICAL WEATHER DISCUSSION
NWS NATIONAL HURRICANE CENTER MIAMI FL
705 PM EST THU NOV 22 2012

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.

...ITCZ/MONSOON TROUGH...

THE MONSOON TROUGH EXTENDS ACROSS W AFRICA TO THE COAST OF
SIERRA LEONE AT 7N12W TO 6N18W. THE ITCZ CONTINUES FROM 6N18W
ALONG 6N36W 8N49W. A SURFACE TROUGH IS EMBEDDED WITHIN THE ITCZ
ALONG 10N51W TO 5N52W. SCATTERED STRONG CONVECTION IS FROM 4N-8N
BETWEEN 21W-30W. SCATTERED MODERATE CONVECTION IS FROM 6N-9N
BETWEEN 30W-46W. SCATTERED MODERATE/ISOLATED STRONG CONVECTION
IS FROM 5N-10N BETWEEN 46W-55W.

...DISCUSSION...

GULF OF MEXICO...
MAINLY ZONAL WESTERLY FLOW COVERS THE GULF OF MEXICO EXCEPT FRO
MORE NW FLOW OVER THE FAR EASTERN GULF AROUND THE WEST SIDE OF
AN UPPER LEVEL TROUGH IN THE WEST ATLC. WATER VAPOR IMAGERY
INDICATES THAT MOSTLY DRY AIR ALOFT SPREADS ACROSS THE AREA
HELPING PROVIDE FAIR CONDITIONS THROUGHOUT THE BASIN. AT THE
SURFACE...RIDGING CONTINUES WITH AXIS EXTENDING FROM A HIGH
CENTER OVER ALABAMA. LIGHT ANTI-CYCLONIC FLOW OF 5-10 KT IS
AROUND THE RIDGE WITH SOME WINDS REACHING 15-20 KT AROUND THE
PERIPHERY INCLUDING THE SE GULF AND THE SW GULF. A FEW ISOLATED
SHOWERS ARE IN THE FAR SW GULF AS WELL NEAR A SURFACE TROUGH
PARALLELING THE MEXICAN COAST ALONG 23N98W TO 18N94W. SURFACE
RIDGING IS EXPECTED TO REMAIN ACROSS THE BASIN UNTIL A COLD
FRONT REACHES THE NW GULF LATE FRIDAY OR EARLY SATURDAY.

CARIBBEAN SEA...
A BROAD UPPER LEVEL RIDGE COVERS THE CARIBBEAN WITH MAINLY DRY
WESTERLY FLOW OVER THE NW CORNER AND THE EASTERN PORTIONS WHILE
MOIST SOUTHWESTERLY FLOW COVERS THE CENTRAL CARIBBEAN. STRONG
NORTHERLY FLOW OF 20-25 KT IS ACROSS THE NW CARIBBEAN. THE WINDS
GET LIGHTER AND EASTERLY ACROSS THE CENTRAL AND EASTERN
CARIBBEAN FORMING SURFACE CONVERGENCE NEAR A SURFACE TROUGH
IN THE CENTRAL CARIBBEAN FROM HISPANIOLA NEAR 18N71W TO
NORTHERN COLOMBIA AT 11N74W. THE COMBINATION OF SURFACE
CONVERGENCE NEAR THE TROUGH ALONG WITH MOIST SOUTHWESTERLY FLOW
ALOFT IS HELPING PRODUCE SCATTERED SHOWERS/POSSIBLE
THUNDERSTORMS SOUTH OF 15N BETWEEN 72W-81W...AS WELL AS ISOLATED
SHOWERS NORTH OF 15N BETWEEN 70W-78W. THE MONSOON TROUGH SOUTH
OF PANAMA AND COSTA RICA MAY ALSO BE PLAYING A ROLE IN THE
ACTIVITY IN THE SW CARIBBEAN. FAIR CONDITIONS ARE ACROSS THE
EASTERN CARIBBEAN. LITTLE CHANGE IS EXPECTED OVER THE NEXT 24
HOURS.

ATLANTIC OCEAN...
A NARROW SHORTWAVE UPPER TROUGH EXTENDS OVER THE FAR W ATLC
SUPPORTING A NEWLY DEVELOPED COLD FRONT THAT EXTENDS FROM A 1000
MB LOW NEAR 33N66W ALONG 25N69W TO 20N74W. AS OF 2100 UTC...A
SURFACE TROUGH IS WEST OF THE FRONT ALONG 30N72W TO 25N76W. DRY
AIR ALOFT IS INHIBITING ANY STRONG SHOWERS/THUNDERSTORMS...BUT A
FEW ISOLATED SHOWERS/THUNDERSTORMS EXIST NORTH OF 30N BETWEEN
66W-76W. POSSIBLE ISOLATED SHOWERS ARE EAST OF THE FRONT  FROM
18N-28N BETWEEN 60W-70W WHERE MOIST SOUTHWESTERLY FLOW ALOFT IS
STREAMING FROM THE CENTRAL CARIBBEAN INTO THE ATLC. A BROAD
UPPER RIDGE COVERS THE CENTRAL ATLC EXTENDING FROM THE EASTERN
CARIBBEAN. THE UPPER RIDGE SUPPORTS A SURFACE RIDGE ANCHORED BY
A 1015 MB HIGH NEAR 22N46W. THE RIDGE IS PROVIDING MOSTLY FAIR
CONDITIONS ACROSS THE CENTRAL AND EASTERN ATLC. A FEW
SHOWERS/THUNDERSTORMS ARE EAST OF THE HIGH CENTER FROM 20N-24N
BETWEEN 40W-43W. AN UPPER LEVEL TROUGH IS EAST OF THE UPPER
RIDGE EXTENDING ALONG 32N30W TO 14N37W TO 6N52W. THE UPPER
TROUGH SUPPORTS A COLD FRONT THAT ENTERS THE DISCUSSION AREA
NEAR 32N30W TO 26N38W. ISOLATED SHOWERS ARE WITHIN 250 NM SE OF
THE FRONT AXIS.

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

$$
WALTON





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