[Tropical] Tropical Weather Discussion

[EMWIN Server]

AXNT20 KNHC 181142
TWDAT

TROPICAL WEATHER DISCUSSION
NWS NATIONAL HURRICANE CENTER MIAMI FL
805 AM EDT FRI MAR 18 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 0600 UTC SURFACE ANALYSIS AND SATELLITE IMAGERY THROUGH
1030 UTC.

...ITCZ...

ITCZ AXIS IS ALONG 07N11W 02N23W CROSSING THE EQUATOR NEAR 34W
AND INTO NE BRAZIL NEAR 03S41W. ISOLATED MODERATE CONVECTION IS
FROM THE EQUATOR TO 07N BETWEEN 17W-25W. SCATTERED MODERATE
CONVECTION IS FROM THE EQUATOR TO 04N BETWEEN 35W-44W.

...DISCUSSION...

GULF OF MEXICO...
AN UPPER LEVEL RIDGE IS OVER THE SE CONUS WITH AXIS FROM SE
LOUISIANA NORTHEASTWARD TO THE MID-ATLC STATES. SOUTH OF THIS
UPPER LEVEL RIDGE MOSTLY ZONAL WESTERLY FLOW ALOFT IS NOTED ON
WATER VAPOR IMAGERY THIS MORNING. DRY AIR AND SUBSIDENCE
ACCOMPANY THE RIDGE WHICH FILTERS DOWN TO THE LOW-LEVELS AS A
FAIRLY STRONG 1026 MB HIGH CENTERED OVER THE NE GULF NEAR
29N85W. IT CONTINUES TO PROVIDE OVERALL FAIR WEATHER TO MUCH OF
THE GULF THIS MORNING. LIGHT EAST TO SOUTHEAST WINDS ARE ACROSS
THE GULF WITH VERY LITTLE SIGNIFICANT PRECIPITATION NOTED ON
SATELLITE AND RADAR IMAGERY. HOWEVER...SHORTWAVE INFRARED
SATELLITE IMAGERY AND A FEW COASTAL OBSERVATIONS ARE INDICATING
LOW-LEVEL STRATUS AND LOWER VISIBILITIES IN FOG OVER THE NW GULF
NORTHWEST OF A LINE FROM 23N97W TO 29N91W...IMPACTING MARINE AND
AVIATION INTERESTS ALONG THE TEXAS AND LOUISIANA GULF COAST. THE
SURFACE RIDGE IS FORECAST TO REMAIN NEARLY STATIONARY OVER THE
NEXT SEVERAL DAYS AND CONTINUE TO PROVIDE OVERALL STABLE WEATHER
CONDITIONS.

CARIBBEAN SEA...
AN UPPER LEVEL ANTICYCLONIC CIRCULATION IS CENTERED EAST OF THE
LESSER ANTILLES NEAR 07N44W AND CONTINUES TO PROVIDE SW WINDS
ALOFT OVER MUCH OF THE CARIBBEAN SEA BASIN. MODERATE DRY AIR AND
SUBSIDENCE IS ASSOCIATED WITH THE UPPER LEVEL RIDGING WHICH
EXTENDS WESTWARD TO 85W. AT THE SURFACE...A STRONG SURFACE HIGH
LOCATED OVER THE NE GULF AND PORTIONS OF THE SW NORTH ATLC
CONTINUES TO PRODUCE A LARGE AREA OF FRESH TO STRONG E-NE TRADES
OVER MUCH OF THE CARIBBEAN. THE STRONGEST WINDS ARE LOCATED IN
THE VICINITY OF THE WINDWARD PASSAGE AND ALSO ALONG THE COAST OF
COLOMBIA...MAINLY S OF 15N BETWEEN 72W-80W. THE HIGH OVER THE SW
NORTH ATLC IS EXPECTED TO REMAIN NEARLY STATIONARY AND
RELATIVELY STRONG OVER THE NEXT FEW DAYS...SO AS A RESULT...THE
TRADES ARE FORECAST TO REMAIN QUITE BRISK THROUGH THE WEEKEND.
ALTHOUGH NO SIGNIFICANT DEEP CONVECTION IS NOTED ON SATELLITE
IMAGERY THIS MORNING...ISOLATED SHOWERS CONTINUE OVER MUCH OF
THE EASTERN HALF OF THE BASIN...WHILE ISOLATED SHOWERS CONTINUE
TO PUSH ONSHORE ALONG THE NICARAGUA...COSTA RICA...AND WESTERN
PANAMA COASTS.

ATLANTIC OCEAN...
AN UPPER LEVEL TROUGH IS PROGRESSING ACROSS THE W ATLC WATERS
WITH AXIS ALONG 33N64W TO 30N66W TO THE FLORIDA COAST NEAR
27N80W. THE UPPER LEVEL TROUGHING SUPPORTS A DISSIPATING COLD
FRONT THAT ENTERS THE DISCUSSION AREA 32N66W AND EXTENDS SW TO
28N71W. A PRE-FRONTAL TROUGH IS ALSO ANALYZED FROM 31N64W TO
28N66W. VERTICAL DISTRIBUTION OF MOISTURE IS VERY LIMITED WITH
THIS FRONT...HOWEVER...MARGINAL LOW-LEVEL CONVERGENCE IS
GENERATING ISOLATED SHOWERS WITHIN 60 NM EITHER SIDE OF THE
FRONT AS IT CONTINUES TO BECOME MORE DIFFUSE. AN EARLIER ASCAT
PASS FROM 18/0224 UTC INDICATES STRONGER NORTHERLY WINDS ARE
LOCATED NW OF THE FRONT. THE FRONT IS FORECAST TO SHIFT NE OVER
THE NEXT 24 HOURS AND LOCATE NORTH OF THE DISCUSSION AREA BY
EARLY SATURDAY. SOUTHEAST OF THIS FRONT...ANOTHER SURFACE TROUGH
IS ANALYZED FROM 27N64W TO 21N68W...PRIMARILY LOCATED WITHIN THE
WEAKNESS OF THE SUBTROPICAL RIDGE BETWEEN 60W-70W. ISOLATED
SHOWERS ARE OCCURRING FROM 24N-27N BETWEEN 61W-66W. FARTHER
EAST...ANOTHER UPPER LEVEL TROUGH IS NOTED ON WATER VAPOR
IMAGERY ALONG 31W THAT SUPPORTS A COLD FRONT ANALYZED FROM
32N29W TO 28N30W THEN SW TO 22N40W. THE REMAINDER OF THE
BOUNDARY STRETCHES WESTWARD TO 23N51W AS A DISSIPATING
STATIONARY FRONT. SCATTERED SHOWERS ARE OCCURRING WITHIN 120 NM
EAST OF THE FRONT N OF 26N WHILE ISOLATED SHOWERS LINGER WITHIN
60 NM EITHER SIDE OF THE FRONT W OF 32W.

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

$$
HUFFMAN



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