[Tropical] Tropical Weather Discussion

[EMWIN Server]

AXNT20 KNHC 240547
TWDAT

TROPICAL WEATHER DISCUSSION
NWS NATIONAL HURRICANE CENTER MIAMI FL
105 AM EST SAT NOV 24 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 0000 UTC SURFACE ANALYSIS AND SATELLITE IMAGERY THROUGH
0515 UTC.

...ITCZ/MONSOON TROUGH...

THE MONSOON TROUGH EXTENDS FROM THE AFRICAN COAST NEAR 11N15W TO
09N18W. THE INTERTROPICAL CONVERGENCE ZONE AXIS EXTENDS FROM
09N18W TO 07N33W TO 05N45W TO 06N54W. A WESTWARD MOVING SURFACE
TROUGH IS ANALYZED FROM 05N-10N ALONG 56W. SCATTERED MODERATE
CONVECTION IS FROM 05N-10N BETWEEN 17W-28W. ISOLATED MODERATE
CONVECTION IS FROM 02N-12N BETWEEN 10W-40W...AND FROM 03N-10N
BETWEEN 53W-60W.

...DISCUSSION...

GULF OF MEXICO...
ZONAL WESTERLY FLOW ALOFT COVERS MUCH OF THE GULF OF MEXICO THIS
EVENING...HOWEVER A DEEP LAYERED TROUGH IS CENTERED WELL NORTH
OF THE AREA OVER THE GREAT LAKES REGION. AN EMBEDDED SHORTWAVE
TROUGH CONTINUES TO PUSH SOUTHEASTWARD OVER THE SE CONUS AND
GULF COASTAL PLAINS THAT SUPPORT A COLD FRONT ANALYZED FROM
MOBILE BAY NEAR 31N88W SW TO THE TEXAS COAST NEAR 28N87W. AND
INLAND OVER SOUTHERN TEXAS AND NORTH-CENTRAL MEXICO. LOW-LEVEL
MOISTURE CONVERGENCE IN THE VICINITY OF THE FRONT COUPLED WITH
MAXIMUM MIDDLE TO UPPER LEVEL DIFFLUENCE N OF 23N BETWEEN
95W-100W IS GENERATING NUMEROUS SHOWERS AND WIDELY SCATTERED
TSTMS OVER PORTIONS OF THE NW GULF WATERS N OF 23N BETWEEN
94W-100W. ELSEWHERE OVER THE GULF THIS EVENING HIGH PRESSURE
DOMINATES ANCHORED BY A 1024 MB HIGH CENTERED NEAR 28N91W.
ANTICYCLONIC SURFACE WINDS IN THE RANGE OF 5 TO 15 KT ARE
EXPECTED TO PREVAIL THROUGH THE OVERNIGHT HOURS INTO SATURDAY.
AS THE FRONT SLIDES SOUTHEASTWARD ON SATURDAY...NORTHERLY WINDS
ARE FORECAST TO INCREASE SLIGHTLY THROUGH EARLY SUNDAY AND
GRADUALLY DECREASE BELOW 20 KT LATE SUNDAY INTO MONDAY AS HIGH
PRESSURE ONCE AGAIN RE-ESTABLISHES ITSELF OVER THE SE CONUS AND
GULF BASIN.

CARIBBEAN SEA...
MUCH OF THE CARIBBEAN IS UNDER THE INFLUENCE OF AN UPPER LEVEL
ANTICYCLONIC CIRCULATION CENTERED SE OF THE WINDWARD ISLANDS
NEAR 11N59W. WHILE THIS CENTER IS EAST OF THE BASIN...MOSTLY
SOUTHWESTERLY WINDS PREVAIL ALOFT AND AN OVERALL DIFFLUENT
ENVIRONMENT IS OVER A GOOD PORTION OF THE CENTRAL CARIBBEAN.
THIS IS DUE LARGELY IN PART TO A MIDDLE TO UPPER LEVEL LOW
CENTERED OVER THE WESTERN ATLC NEAR 36N61W THAT DIPS TROUGHING
TO THE SW AND OVER THE NORTH-CENTRAL PORTION OF THE BASIN.
LOW-LEVEL MOISTURE CONVERGENCE IS MAXIMIZED ALONG A SURFACE
TROUGH ANALYZED FROM NORTHERN COLOMBIA NEAR 11N73W TO SOUTH-
CENTRAL HISPANIOLA NEAR 18N72W THAT CONTINUES TO PROVIDE FOCUS
FOR SCATTERED SHOWERS WITHIN 240 NM EITHER SIDE OF A LINE FROM
19N69W TO 09N82W...INCLUDING HISPANIOLA AND PUERTO RICO.
OTHERWISE...THE NW CARIBBEAN REMAINS UNDER FAIR CONDITIONS AS
SURFACE RIDGING EXTENDS INTO THE REGION FROM THE GULF OF MEXICO
AND THE SE CARIBBEAN CONTINUES TO SHOW CLEAR SKIES FOR THE
OVERNIGHT HOURS DUE TO A CENTRAL ATLC SURFACE RIDGE AXIS.

ATLANTIC OCEAN...
A MIDDLE TO UPPER LEVEL LOW IS CENTERED NEAR 36N61W THAT
SUPPORTS A PAIR OF COLD FRONTS ANALYZED INTO THE SW NORTH ATLC
WATERS. THE EASTERN-MOST COLD FRONT REMAINS IN A DISSIPATING
STAGE...HOWEVER HAS THE MOST ACTIVE CONVECTION ASSOCIATED WITH
IT AT THIS TIME. THE FRONT EXTENDS FROM 32N55W TO 25N58W TO
19N69W WITH SCATTERED SHOWERS AND ISOLATED TSTMS OCCURRING FROM
22N-32N BETWEEN 43W-58W. THE SECONDARY REINFORCING COLD FRONT IS
ANALYZED FROM 32N59W TO 27N62W TO 21N76W WITH VERY LITTLE IF ANY
SHOWER ACTIVITY ASSOCIATED WITH IT. HOWEVER...EXAMINING TOTAL
PRECIPITABLE WATER IMAGERY IT DOES SHOW A SLIGHTLY DRIER AND
MORE STABLE AIRMASS TO THE NW OF THE COLD FRONT. FARTHER
EAST...A MIDDLE TO UPPER LEVEL SHORTWAVE TROUGH IS NOTED ON
WATER VAPOR IMAGERY NEAR 38N32W THAT SUPPORTS A COLD FRONT
ANALYZED FROM 32N22W TO 31N25W THAT BECOMES STATIONARY ALONG 31N
TO 38W THEN TO BEYOND 32N40W. A PRE-FRONTAL SURFACE TROUGH ALSO
EXTENDS FROM THE MADEIRA ISLANDS NEAR 33N17W TO 27N29W. ISOLATED
SHOWERS ARE OCCURRING WITHIN 120 NM EITHER SIDE OF THE FRONT AND
SURFACE TROUGH AXIS. OTHERWISE...THE REMAINDER OF THE CENTRAL
AND EASTERN ATLC IS UNDER THE INFLUENCE OF SURFACE RIDGING
ANCHORED BY A 1018 MB HIGH CENTERED NEAR 26N43W.

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

$$
HUFFMAN




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