[Tropical] Tropical Weather Discussion

[EMWIN Server]

AXNT20 KNHC 112348
TWDAT

TROPICAL WEATHER DISCUSSION
NWS NATIONAL HURRICANE CENTER MIAMI FL
705 PM EST SAT JAN 11 2014

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...
A STRONG PRESSURE GRADIENT EXISTS BETWEEN AN AREA OF LOWER
PRESSURE OVER NORTHERN SOUTH AMERICA AND A STRONG SURFACE RIDGE
ANCHORED TO THE NORTH-NORTHEAST ACROSS THE SW NORTH ATLC BY A
1031 MB HIGH CENTERED NEAR 35N59W. PERSISTENT TRADES IN THE
RANGE OF 25 TO 35 KT ARE EXPECTED THROUGH LATE SUNDAY. SEE
LATEST NWS HIGH SEAS FORECAST UNDER AWIPS/WMO HEADERS MIAHSFAT2/
FZNT02 KNHC FOR MORE DETAILS.

AN AREA OF LOW PRESSURE IS FORECAST TO FORM IN THE VICINITY OF
21N38W SOUTH OF AN EASTERN ATLC SUBTROPICAL RIDGE. AS THE LOW
FORMS AND MOVES NORTHWARD...A STRONG PRESSURE GRADIENT IS
EXPECTED TO RESULT GENERATING GALE FORCE WINDS IN THE NORTHERN
SEMICIRCLE BY 13/0000 UTC. SEE LATEST NWS HIGH SEAS FORECAST
UNDER AWIPS/WMO HEADERS MIAHSFAT2/FZNT02 KNHC FOR MORE DETAILS.

...ITCZ/MONSOON TROUGH...
THE MONSOON TROUGH EXTENDS FROM THE AFRICAN COAST NEAR 07N12W TO
04N18W. THE INTERTROPICAL CONVERGENCE ZONE AXIS EXTENDS FROM
04N18W TO 03N23W TO 04N34W TO 01N42W. WIDELY SCATTERED MODERATE
CONVECTION IS FROM 01N-06N BETWEEN 09W-37W.

...DISCUSSION...

GULF OF MEXICO...
A RELATIVELY SHARP MIDDLE TO UPPER LEVEL TROUGH IS PROGRESSING
OVER THE EASTERN CONUS WITH AXIS ALONG 89W THAT DIPS SOUTHWARD
TO A BASE OVER THE LOWER MISSISSIPPI RIVER VALLEY IN THE
VICINITY OF 31N90W. THIS TROUGHING SUPPORTS A COLD FRONT
ANALYZED INTO THE GULF NEAR 30N92W AND EXTENDS W-SW TO THE TEXAS
GULF COAST NEAR 28N97W. WHILE THE FRONT REMAINS QUIET WITH
REGARDS TO CONVECTION THIS EVENING...A PRE-FRONTAL TROUGH...WITH
PORTIONS OF EMBEDDED SQUALLS...EXTENDS FROM NORTHERN FLORIDA
NEAR 30N83W SW TO 27N86W TO 24N93W. MOSAIC DOPPLER RADAR AND
LIGHTNING DATA INDICATE NUMEROUS SHOWERS AND SCATTERED TSTMS
OCCURRING WITHIN 60 NM EITHER SIDE OF THE SQUALL LINE/SURFACE
TROUGH AXIS N OF 27N. THE COLD FRONT IS EXPECTED TO MOVE EAST OF
THE GULF BASIN BY EARLY SUNDAY AS A SURFACE RIDGE MOVES FROM
CENTRAL TEXAS EASTWARD TO THE GULF COASTAL PLAINS. GENERALLY 10
TO 15 KT ANTICYCLONIC WINDS ARE EXPECTED SUNDAY ON THE SOUTHERN
PERIPHERY OF THE RIDGING. AS THIS RIDGE SLIDES EASTWARD INTO THE
SW NORTH ATLC MONDAY...THE NEXT COLD FRONT IS FORECAST TO EMERGE
OFF THE TEXAS AND LOUISIANA COAST BY MID-DAY MONDAY.

CARIBBEAN SEA...
MUCH OF THE CARIBBEAN REMAINS FAIRLY TRANQUIL THIS EVENING WITH
THE EXCEPTION OF GALE FORCE WINDS OCCURRING OFF THE COAST OF
COLOMBIA. WATER VAPOR IMAGERY INDICATES VERY DRY AND STABLE AIR
ALOFT DUE TO UPPER TO MIDDLE LEVEL RIDGING ANCHORED BY A MID-
LEVEL ANTICYCLONE CENTERED OVER THE WINDWARD PASSAGE NEAR
20N74W. A FEW PASSING ISOLATED LOW-TOPPED SHOWERS ARE NOTED ON
SATELLITE IMAGERY...BUT THE MAIN IMPACT REMAINS TO BE STRONG
TRADES DUE TO A STRONG PRESSURE GRADIENT BETWEEN LOWER PRESSURE
ACROSS NORTHERN SOUTH AMERICA AND A SURFACE RIDGE ANCHORED
ACROSS THE SW NORTH ATLC. TRADES ARE EXPECTED TO REMAIN IN THE
RANGE OF 20 TO 30 GENERALLY BETWEEN 68W-82W THROUGH THE
OVERNIGHT PERIOD INTO SUNDAY.

...HISPANIOLA...
CURRENTLY ONLY A FEW ISOLATED LOW-TOPPED SHOWERS ARE MOVING
ACROSS THE ISLAND THIS EVENING BENEATH AN OTHERWISE FAIR AND
STABLE ENVIRONMENT ALOFT DUE TO A THE PRESENCE OF A BROAD UPPER
LEVEL RIDGE IN THE REGION. EXPECT THE OVERALL TRANQUIL
CONDITIONS TO PERSIST OVER THE NEXT SEVERAL DAYS.

ATLANTIC OCEAN...
MOSTLY SOUTHWESTERLY MIDDLE TO UPPER LEVEL FLOW IS NOTED ON
WATER VAPOR IMAGERY OVER THE SW NORTH ATLC THIS EVENING BETWEEN
AN APPROACHING UPPER LEVEL TROUGH OVER THE EASTERN CONUS AND AN
UPPER LEVEL RIDGE WITH AXIS EXTENDING FROM OVER THE WINDWARD
PASSAGE REGION NEAR 20N74W N-NE TO BEYOND 35N64W. UPPER LEVEL
DIFFLUENCE EAST OF THE UPPER LEVEL TROUGHING ALONG WITH LOW-
LEVEL MOISTURE CONVERGENCE IN ADVANCE OF THE ASSOCIATED COLD
FRONTAL BOUNDARY IS GENERATING SCATTERED SHOWERS AND TSTMS WEST
OF A LINE FROM 29N81W TO 32N77W. OTHERWISE...THE REMAINDER OF
THE SW NORTH ATLC IS UNDER MOSTLY FAIR SKIES AND CONDITIONS THIS
EVENING DUE TO A CENTRAL ATLC RIDGE ANCHORED BY A 1031 MB HIGH
CENTERED NEAR 35N59W. THIS RIDGING COVERS MUCH OF THE CENTRAL
ATLC PORTION OF THE BASIN...HOWEVER ACROSS THE EASTERN ATLC...A
COLD FRONT ENTERS THE DISCUSSION AREA NEAR 32N24W EXTENDING SW
TO 24N45W. ISOLATED SHOWERS ARE OCCURRING WITHIN 120 NM EITHER
SIDE OF THE FRONT.

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

$$
HUFFMAN


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