[Tropical] Tropical Weather Discussion

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AXNT20 KNHC 142340
TWDAT

TROPICAL WEATHER DISCUSSION
NWS NATIONAL HURRICANE CENTER MIAMI FL
805 PM EDT THU MAR 14 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 1800 UTC SURFACE ANALYSIS AND SATELLITE IMAGERY THROUGH
2315 UTC.

...ITCZ/MONSOON TROUGH...

THE MONSOON TROUGH EXTENDS FROM THE AFRICAN COAST NEAR 08N13W TO
06N13W TO 03N17W. THE INTERTROPICAL CONVERGENCE ZONE AXIS
EXTENDS FROM 03N17W TO 01N25W TO 01N36W TO THE EQUATOR NEAR 41W.
ISOLATED MODERATE CONVECTION IS S OF 06N BETWEEN 10W-37W.

...DISCUSSION...

GULF OF MEXICO...
MOIST SOUTHWESTERLY FLOW IS NOTED ON WATER VAPOR IMAGERY IN THE
UPPER LEVELS OF THE ATMOSPHERE WHILE MID-LEVEL NORTHWESTERLY
FLOW CONTINUES TO PROVIDE A DRYING EFFECT OVER THE GULF THIS
EVENING. SATELLITE IMAGERY INDICATES MOST OF THE MIDDLE TO HIGH
LEVEL CLOUDINESS IS REMAINS S OF 27N THIS EVENING WITH POSSIBLE
ISOLATED SHOWERS OCCURRING ACROSS THE SW GULF WATERS S OF
21N...INCLUDING INLAND PORTIONS OF SOUTHERN MEXICO. AT THE
SURFACE...MOSTLY FAIR CONDITIONS ARE OBSERVED AS A RIDGE REMAINS
ANCHORED ACROSS THE SE CONUS BY A 1030 MB HIGH CENTERED OVER THE
LOWER MISSISSIPPI RIVER VALLEY. A SECONDARY AND LOCALIZED RIDGE
IS CENTERED ON A 1030 MB HIGH ACROSS COASTAL EAST-CENTRAL MEXICO
NEAR 23N99W. WITH THE RIDGE EXPECTED TO BUILD S-SE OVER THE NEXT
12 TO 24 HOURS...NORTHEASTERLY WINDS IN THE RANGE OF 10 TO 20 KT
WILL PERSIST ACROSS MUCH OF THE GULF THROUGH EARLY FRIDAY.
THEREAFTER AS THE RIDGE SLIDES EASTWARD OVER THE WEEKEND...
SOUTHERLY RETURN FLOW WILL ONCE AGAIN RE-ESTABLISH ITSELF ACROSS
THE GULF AHEAD OF A DEVELOPING AREA OF WEAK LOW PRESSURE OVER
THE SOUTHERN PLAINS.

CARIBBEAN SEA...
SOUTHWESTERLY UPPER LEVEL FLOW IS NOTED ON WATER VAPOR IMAGERY
THIS EVENING ACROSS MUCH OF THE CARIBBEAN. WHILE MOST OF THE
MOISTURE AND CLOUDINESS IS ASSOCIATED WITH HIGH LEVEL CLOUDS
STREAMING NORTHEASTWARD...A COLD FRONT REMAINS ANALYZED OVER THE
NORTHWEST PORTION OF THE BASIN FROM EASTERN CUBA NEAR 20N76W SW
TO NORTHERN HONDURAS NEAR 15N87W. LOW-LEVEL MOISTURE CONVERGENCE
IN THE VICINITY OF THE FRONT IS GENERATING A NARROW BAND OF
WIDELY SCATTERED SHOWERS OCCURRING WITHIN 180 NM NORTHWEST OF
THE FRONT...INCLUDING ACROSS EASTERN CUBA...THE CAYMAN
ISLANDS...HONDURAS...BELIZE...AND GUATEMALA. STRONGER NORTHEAST
WINDS FOLLOW IN WAKE OF THE FRONT IN THE RANGE OF 20 TO 25 KT
AND THIS AREA OF WIND IS EXPECTED TO SHIFT GRADUALLY SE WITH THE
MOVEMENT OF THE FRONT OVER THE NEXT 24 TO 36 HOURS. BY
SATURDAY...THE FRONT IS FORECAST TO DISSIPATE WITH TRADE WINDS
BECOMING DOMINATE ONCE AGAIN. FINALLY...THE WESTERN EXTENT OF A
CENTRAL ATLC SHEAR LINE IS ANALYZED INTO THE SE CARIBBEAN ALONG
10N58W TO 12N65W. ISOLATED SHOWERS ARE OCCURRING WITHIN 75 NM
EITHER SIDE OF THE SHEAR LINE IMPACTING TRINIDAD AND
TOBAGO...ALONG WITH PORTIONS OF NE VENEZUELA.

ATLANTIC OCEAN...
MIDDLE TO UPPER LEVEL TROUGHING IS ACROSS MUCH OF THE WESTERN
NORTH ATLC WITH AXIS EXTENDING INTO THE DISCUSSION AREA NEAR
32N70W TO 27N80W THAT SUPPORTS A COLD FRONT ANALYZED FROM 32N62W
SW TO THE SE BAHAMAS NEAR 22N73W TO EASTERN CUBA NEAR 20N76W AND
INTO THE WESTERN CARIBBEAN SEA. ISOLATED SHOWERS ARE OCCURRING
WITHIN 120 NM EITHER SIDE OF THE FRONT THIS EVENING. THE
REMAINDER OF THE SW NORTH ATLC IS UNDER THE INFLUENCE OF A
SURFACE RIDGE BUILDING IN ACROSS THE SE CONUS AND EASTERN GULF
OF MEXICO. THE RIDGE IS ANCHORED BY A 1030 MB HIGH CENTERED OVER
THE LOWER MISSISSIPPI RIVER VALLEY. FARTHER EAST...THE CENTRAL
ATLC IS BETWEEN TWO LOWER PRESSURE AREAS WITH A WEAK RIDGE
ANCHORED BY A 1016 MB HIGH CENTERED NEAR 24N61W. THIS RIDGE IS
EXPECTED TO CONTINUE ERODING DUE TO THE APPROACHING FRONTAL
BOUNDARY. FINALLY...OVER THE EASTERN ATLC...A MIDDLE TO UPPER
LEVEL LOW IS CENTERED NEAR 32N35W THAT SUPPORTS A COMPLEX AREA
OF LOW PRESSURE CENTERED MAINLY ON A 998 MB LOW NEAR 31N35W. A
COLD FRONT EXTENDS FROM THE LOW CENTER S-SW TO 27N34W TO 20N40W
TO 18N44W. ISOLATED SHOWERS AND TSTMS ARE OCCURRING N OF 25N
BETWEEN 26W-34W. IN ADDITION...A PRE-FRONTAL SURFACE TROUGH IS
FROM 25N32W TO 15N41W AND BECOMES A SHEAR LINE TO 10N56W TO
12N65W IN THE SE CARIBBEAN SEA. ISOLATED SHOWERS ARE OCCURRING
WITHIN 75 NM EITHER SIDE OF THE BOUNDARY.

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

$$
HUFFMAN


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