[Tropical] Tropical Weather Discussion

[EMWIN Server]

AXNT20 KNHC 132353
TWDAT

TROPICAL WEATHER DISCUSSION
NWS NATIONAL HURRICANE CENTER MIAMI FL
805 PM EDT SUN MAR 13 2011

TROPICAL WEATHER DISCUSSION FOR NORTH AMERICA...CENTRAL
AMERICA...GULF OF MEXICO...CARIBBEAN SEA...NORTHERN SECTION OF
SOUTH AMERICA...AND ATLANTIC OCEAN TO THE AFRICAN COAST FROM THE
EQUATOR TO 32N. THE FOLLOWING INFORMATION IS BASED ON SATELLITE
IMAGERY...METEOROLOGICAL ANALYSIS...WEATHER OBSERVATIONS...AND
RADAR.

BASED ON 1800 UTC SURFACE ANALYSIS AND SATELLITE IMAGERY THROUGH
2315 UTC.

...ITCZ...

ITCZ AXIS IS ANALYZED ALONG 05N09W CROSS THE EQUATOR NEAR 17W
THEN CONTINUING ALONG 03S25W TO 02S35W AND INTO NE BRAZIL NEAR
04S39W. SCATTERED MODERATE TO STRONG CONVECTION IS OVER INTERIOR
PORTIONS OF W AFRICA FROM 05N-10N BETWEEN 06W-12W. ELSEWHERE...
FARTHER WEST...A SURFACE TROUGH IS ANALYZED ON THE WESTERN
EXTENT OF THE ITCZ AXIS FROM 01N42W TO 09S38W. SCATTERED
MODERATE CONVECTION IS OCCURRING OVER THE ATLC WATERS FROM 02N
TO 07N BETWEEN 38W-53W.

...DISCUSSION...

GULF OF MEXICO...
NEARLY ZONAL WESTERLY FLOW ALOFT IS NOTED ON WATER VAPOR IMAGERY
THIS EVENING WITH MODERATELY DRY AIR LOCATED OVER THE
SOUTHEASTERN HALF OF THE GULF BASIN. HOWEVER...INCREASED UPPER
LEVEL MOISTURE IS LOCATED OVER THE NW HALF OF THE GULF AHEAD OF
AN APPROACHING MIDDLE TO UPPER LEVEL SHORTWAVE TROUGH CURRENTLY
ACROSS THE INTERMOUNTAIN WEST. HOWEVER THIS EVENING...THE
RELATIVELY BENIGN UPPER LEVELS ARE CONTINUING TO SUPPORT AN
ELONGATED SURFACE RIDGE ANCHORED BY A 1026 MB HIGH CENTERED OFF
THE COAST OF FLORIDA IN THE SW NORTH ATLC NEAR 28N78W. THE RIDGE
AXIS EXTENDS ALONG 28N ACROSS THE NORTHERN GULF WITH SE WINDS IN
THE RANGE OF 10 TO 20 KT. THE RIDGE IS EXPECTED TO REMAIN NEARLY
STATIONARY OVER THE SW NORTH ATLC...WHILE THE NEXT COLD FRONT IS
FORECAST TO EMERGE OFF THE TEXAS AND LOUISIANA GULF COASTS LATE
MONDAY INTO EARLY TUESDAY. THE FRONT IS EXPECTED TO LARGELY
IMPACT THE GULF WATERS N OF 25N.

CARIBBEAN SEA...
A BROAD UPPER LEVEL RIDGE AXIS EXTENDS FROM THE TROPICAL ATLC
NEAR 10N54W W-NW OVER THE CARIBBEAN SEA BASIN TO 18N80W
PROVIDING MOSTLY S TO SW FLOW ALOFT. STRONG SUBSIDENCE AND DRY
STABLE AIR ACCOMPANY THIS UPPER LEVEL FEATURE WHICH CONTINUES TO
PROVIDE OVERALL FAIR CONDITIONS OVER MUCH OF THE CARIBBEAN THIS
EVENING. ENHANCED E-NE TRADES CONTINUE DUE TO A STRONG PRESSURE
GRADIENT BETWEEN THE HIGH PRESSURE RIDGE LOCATED OVER THE SW
NORTH ATLC AND LOWER PRESSURE OVER NORTHERN SOUTH AMERICA.
EARLIER MORNING AND AFTERNOON ASCAT PASSES DEPICTED THESE TRADES
IN THE RANGE OF 15 TO 25 KT WITH THE STRONGEST NE WINDS NOTED
SOUTH OF HISPANIOLA...IN THE VICINITY OF THE WINDWARD PASSAGE...
AND ALONG THE IMMEDIATE COAST OF NORTHERN COLOMBIA. ASIDE FROM
THE WIND FIELD...LOW-LEVEL MOISTURE CONTINUES TO ADVECT WESTWARD
WITH ISOLATED SHOWERS OVER THE NE CARIBBEAN...INCLUDING THE
PUERTO RICO AND THE MONA PASSAGE...AS WELL AS AN AREA S OF 14N
BETWEEN 64W-74W...INCLUDING THE ABC ISLANDS...AND AN AREA SOUTH
OF JAMAICA FROM 14N-18N BETWEEN 73W-83W.

ATLANTIC OCEAN...
UPPER LEVEL TROUGHING IS LOCATED OVER MUCH OF THE WESTERN ATLC
DIPPING SOUTHWARD TO 29N BETWEEN 55W-80W. WATER VAPOR IMAGERY
INDICATES MOSTLY DRY AND AND SUBSIDENCE ACCOMPANIES THE BASE OF
THE TROUGHING THAT CONTINUES TO SUPPORT A 1026 MB HIGH CENTERED
OFF THE FLORIDA COAST NEAR 28N78W. THE RIDGE AXIS EXTENDS E-NE
TO BERMUDA...AND WESTWARD ALONG 28N INTO THE NORTHERN GULF OF
MEXICO. MOSTLY FAIR CONDITIONS ARE ASSOCIATED WITH THE SURFACE
RIDGE...HOWEVER...STRONG NE WINDS ARE LOCATED WITHIN 210 NM NW
OF A SHEAR LINE ANALYZED FROM 25N65W TO THE WINDWARD PASSAGE
NEAR 20N75W. ISOLATED SHOWERS ARE ALSO OCCURRING WITHIN 75 NM
EITHER SIDE OF THE SHEAR LINE. FARTHER EAST...A DISSIPATING
STATIONARY FRONT ENTERS THE DISCUSSION AREA NEAR 32N58W AND
EXTENDS S-SW TO 24N63W. STRONGER UPPER LEVEL DYNAMICS ARE
LOCATED N OF THE REGION WITH ISOLATED SHOWERS OCCURRING WITHIN
120 NM EITHER SIDE OF THE FRONT. THE REMAINDER OF THE CENTRAL
AND EASTERN ATLC BETWEEN 25W-55W IS UNDER THE INFLUENCE OF A
SURFACE RIDGE ANCHORED BY A 1032 MB HIGH CENTERED NORTH OF THE
REGION NEAR 40N40W. A RELATIVELY STRONG PRESSURE GRADIENT STILL
REMAINS OVER THE AREA FROM 20N-28N BETWEEN 30W-50W. ELSEWHERE...
AN UPPER LEVEL TROUGH AXIS EXTENDS ALONG 32N19W TO 21N32W OVER
THE NE TROPICAL ATLC AND CONTINUES TO SUPPORT A COMPLEX AREA OF
SURFACE LOW PRESSURE OVER THE IBERIAN PENINSULA AND NORTHERN
MOROCCO. A DISSIPATING COLD FRONT EXTENDS ALONG THE W AFRICA
COAST FROM 30N12W TO 25N16W TO 21N26W WITH A SECONDARY WAVE OF
ENERGY IN THE FORM OF A SURFACE TROUGH ANALYZED TO THE WEST
ALONG 32N13W TO 25N22W. POSSIBLE ISOLATED SHOWERS ARE REMAINING
N OF 20N E OF 25W.

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

$$
HUFFMAN




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