[Tropical] Tropical Weather Discussion

[EMWIN Server]

AXNT20 KNHC 171741
TWDAT

TROPICAL WEATHER DISCUSSION
NWS NATIONAL HURRICANE CENTER MIAMI FL
205 PM EDT SUN MAR 17 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.

...ITCZ/MONSOON TROUGH...

THE MONSOON TROUGH EXTENDS FROM THE AFRICAN COAST NEAR 10N14W TO
07N16W TO 06N19W. THE INTERTROPICAL CONVERGENCE ZONE AXIS
EXTENDS FROM 06N19W TO 04N24W TO 01N28W TO THE EQUATOR NEAR 31W
AND ALONG THE EQUATOR TO 42W. SCATTERED MODERATE CONVECTION IS S
OF 04N BETWEEN 21W-32W.

...DISCUSSION...

GULF OF MEXICO...
MOIST SOUTHWESTERLY UPPER LEVEL FLOW IS EVIDENT ON WATER VAPOR
IMAGERY WITH MID-LEVEL SHORTWAVE ENERGY PROGRESSING
NORTHEASTWARD ACROSS THE NORTHERN GULF CENTERED NEAR 28N92W.
THIS FEATURE ALOFT IS PROVIDING FOR INCREASED CLOUDINESS ACROSS
THE BASIN GENERALLY N OF 24N W OF 93W. MOSAIC DOPPLER RADAR AND
LIGHTNING DATA ALSO INDICATE WIDELY SCATTERED SHOWERS AND
ISOLATED ELEVATED TSTMS ARE OCCURRING OVER THIS AREA INCLUDING
INLAND COASTAL LOCATIONS S OF 31N BETWEEN 84W-90W. OTHERWISE...
SOUTHERLY RETURN FLOW DOMINATES ACROSS THE GULF THIS AFTERNOON
ON THE WESTERN PERIPHERY OF A BROAD EAST-WEST ORIENTED RIDGE
ANCHORED IN THE SW NORTH ATLC. THE SHORTWAVE TROUGH IS FORECAST
TO CONTINUE ITS NE MOVEMENT OVER THE NEXT 12 TO 24 HOURS WITH
SOUTHERLY SURFACE WINDS PERSISTING THROUGH LATE MONDAY AS THE
RIDGING GRADUALLY SLIDES EASTWARD. BY EARLY TUESDAY A WEAK FRONT
IS EXPECTED TO EMERGE OFF THE TEXAS AND LOUISIANA COAST.

CARIBBEAN SEA...
UPPER LEVEL SOUTHWESTERLY FLOW IS NOTED ON WATER VAPOR IMAGERY
DUE TO A BROAD ANTICYCLONIC CIRCULATION CENTERED WELL SE OF THE
BASIN NEAR 06N55W. WHILE MOST OF THE SOUTHWESTERLY FLOW IS DRY
AND FAIRLY STABLE...A FEW AREAS OF LOW-LEVEL MOISTURE AND
PRECIPITATION ARE OCCURRING ACROSS THE BASIN. A SHEAR LINE IS
ANALYZED ACROSS THE CENTRAL ATLC TO A TERMINUS NE OF THE LEEWARD
ISLANDS NEAR 18N61W. RESIDUAL MOISTURE AND ISOLATED SHOWERS
CONTINUE TO DRIFT SW OVER THE NE CARIBBEAN REMAINING N OF 16N E
OF 68W. ANOTHER AREA OF ISOLATED SHOWERS ACCORDING TO SATELLITE
IMAGERY IS FOUND S OF 14N BETWEEN 63W-74W. MOST OF THE REMAINDER
OF THE CARIBBEAN IS UNDER THE INFLUENCE OF TRADE WINDS IN THE
RANGE OF 15 TO 25 KT WITH THE STRONGEST AREA LOCATED GENERALLY S
OF 17N BETWEEN 69W-79W...AND IN CLOSE VICINITY TO THE COAST OF
COLOMBIA. THIS SYNOPTIC PATTERN IS EXPECTED TO PERSIST THROUGH
MID-WEEK.

ATLANTIC OCEAN...
GENERALLY WESTERLY MIDDLE TO UPPER LEVEL FLOW IS DOMINATE OVER
MUCH OF THE ATLC BASIN W OF 40W WITH A FAIRLY BROAD SURFACE
RIDGE COMPLETING THE VERTICAL PROFILE OF OVERALL STABLE
CONDITIONS THIS AFTERNOON. THE SURFACE RIDGING IS ANCHORED BY A
1025 MB HIGH CENTERED NEAR 27N62W. TO THE EAST...A MID-LEVEL
SHORTWAVE TROUGH IS NOTED ON WATER VAPOR IMAGERY CENTERED IN THE
VICINITY OF 35N33W THAT SUPPORTS A COLD FRONT ANALYZED INTO THE
DISCUSSION AREA NEAR 32N34W. THE FRONT EXTENDS SW TO 25N40W TO
23N46W AND THEN BECOMES A SHEAR LINE TO 22N50W TO 18N61W.
ISOLATED SHOWERS ARE OCCURRING WITHIN 90 NM EITHER SIDE OF THE
FRONT AND WITHIN 120 NM EITHER SIDE OF THE SHEAR LINE AXIS. THE
BROAD RIDGING IS FORECAST TO EXPAND ITS INFLUENCE NEARLY THE
ENTIRE DISTANCE ACROSS THE ATLC WITH AXIS ALONG 27N/28N BY LATE
MONDAY. THE NEXT COLD FRONT TO EMERGE OFF THE SE U.S. COAST IS
EXPECTED EARLY TUESDAY.

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

$$
HUFFMAN


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