[Tropical] Tropical Weather Discussion

[EMWIN Server]

AXNT20 KNHC 192336
TWDAT

TROPICAL WEATHER DISCUSSION
NWS TPC/NATIONAL HURRICANE CENTER MIAMI FL
805 PM EDT THU MAR 19 2009

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...METEOROLOGICAL ANALYSIS...WEATHER
OBSERVATIONS...AND RADAR.

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

...ITCZ...
ITCZ AXIS IS CENTERED ALONG 4N8W 1N20W CROSSING THE EQUATOR NEAR
27W EXTENDING TO NE BRAZIL NEAR 2S43W. CLUSTERS OF ISOLATED
MODERATE CONVECTION IS WITHIN 90 NM OF THE ITCZ BETWEEN 9W AND
27W.

...DISCUSSION...

GULF OF MEXICO...
AS OF 2100 UTC...A QUASI-STATIONARY SURFACE TROUGH IS CENTERED
OVER THE CENTRAL GULF OF MEXICO FROM 22N89W TO 27N90W. A BAND OF
BROKEN LOW CLOUDS WITH ISOLATED SHOWERS AND POSSIBLE
THUNDERSTORMS ARE OVER THE N CENTRAL GULF WITHIN 45-60 NM OF A
LINE FROM 25N86W TO 26N90W TO 26N93W. MOSTLY FAIR SKIES REMAIN
OVER THE W GULF AS A RIDGE AXIS EXTENDS ALONG THE TEXAS COAST
AND SOUTHWARD TO THE BAY OF CAMPECHE WITH A 1020 MB HIGH ABOUT
120 NM ENE OF VERACRUZ MEXICO. SURFACE WINDS ARE FROM THE NE TO
E AT 10 TO 15 KT OVER THE GULF...DECREASING TO 5-10 KT CLOSER TO
THE COAST. IN THE UPPER LEVELS...A WEAK UPPER LEVEL SHORTWAVE
TROUGH EXTENDS FROM THE RIO GRANDE VALLEY SOUTHWARD TO NEAR
MEXICO CITY WAS MOVING E AT 10-15 KT. MOSTLY ZONAL FLOW WAS
NOTED OVER THE REMAINDER OF THE E-CENTRAL GULF. THE WEAK
SHORTWAVE OVER THE EASTERN GULF HAS MOVED INTO THE W ATLC NEAR
THE BAHAMAS.

CARIBBEAN SEA...
FRESH TRADEWINDS ARE OVER THE EASTERN AND SOUTHWESTERN CARIBBEAN
SEA WITH THE LAST SCATTEROMETER PASS INDICATING WINDS UP TO 25
KT IN ALONG THE COAST OF NRN COLOMBIA. A SHIP WITH CALL SIGN
ZCDF4 WAS ALONG THE COAST OF COLOMBIA AND REPORTED 25 TO 30 KT
WINDS AND 11 FT SEAS OVER THE PAST FEW HOURS. LIGHT WINDS
PREVAIL OVER THE NORTHERN CARIBBEAN WITH SPEEDS IN THE 5 TO 10
KT RANGE...AS SUBSIDENCE AND FAIR WEATHER PREDOMINATE.
HOWEVER...A FEW PATCHES OF BROKEN LOW CLOUDS WITH SCATTERED
SHOWERS AND ISOLATED THUNDERSTORMS CONTINUE NEAR HISPANIOLA
...JAMAICA...AND CUBA. THESE SHOWERS HAVE WEAKENED AS DAYTIME
HEATING WANES AND THE ATMOSPHERE HAS BECOME MORE STABLE. THERE
WAS ALSO A MARKED DECREASE IN LIGHTNING DATA COVERAGE OVER CUBA
AS WELL. IN THE UPPER LEVELS...WEAK ZONAL FLOW WILL PERSIST OVER
THE AREA OVER THE NEXT 24 HOURS...AS A WEAK SHORT WAVE PASSES TO
THE N OF THE REGION OVER THE SW ATLANTIC.

ATLANTIC OCEAN...
A STRONG COLD FRONT EXTENDS FROM 32N43W SW ALONG 26N50W TO
23N62W...THEN BECOMES STATIONARY ALONG 24N WHILE EXTENDING
WESTWARD THROUGH THE CENTRAL BAHAMAS. A 1250 UTC ASCAT PASS
INDICATED GALE FORCE WINDS BRUSHING THE NORTHERN PERIPHERY OF
THE DISCUSSION AREA WITH NEAR STORM FORCE WINDS FURTHER N.
A SHIP WITH CALL SIGN PCBV LOCATED NEAR 30N48W AT 18 UTC
REPORTED GALE FORCE WEST WINDS AND 26 FT SEAS. THE GALES ARE
EXPECTED TO MOVE N OF THE DISCUSSION AREA OVERNIGHT AS THE
PARENT SYSTEM MOVES NE. OVERCAST LOW AND MID CLOUDS WITH
SCATTERED SHOWERS ARE WITHIN 60 NM EITHER SIDE OF THE FRONT AND
ARE EXPECTED TO PERSIST INTO FRI. AN AREA OF SCATTERED SHOWERS
AND ISOLATED THUNDERSTORMS CURRENTLY N OF THE FRONT TO 29N
BETWEEN 70W AND 76W IS SPREADING NE AHEAD OF AN UPPER LEVEL
SHORTWAVE TROUGH. A 1024 MB HIGH IS JUST N OF THE DISCUSSION
AREA CENTERED NEAR 35N62W...WITH A RIDGE EXTENDING SE TO
26N58W...BEHIND THE COLD FRONT. ANOTHER COLD FRONT FURTHER EAST
EXTENDS FROM 32N15W SW TO 26N20W TO 24N33W. SCATTERED SHOWERS
ARE WITHIN 60 NM EITHER SIDE OF THE FRONT... AND ARE EXPECTED TO
DIMINISH OVER THE NEXT 24 HOURS AS THE FRONT WEAKENS. IN THE
UPPER LEVELS...A RATHER SHARP UPPER LEVEL SHORTWAVE TROUGH
IS SWEEPING ACROSS THE CENTRAL BAHAMAS AND APPEARS TO BE
AMPLIFYING WITH TIME AND PRODUCING A LARGE AREA OF MULTILAYERED
CLOUDS AS NOTED ABOVE. ELSEWHERE N OF 20N...A PREDOMINANTLY
ZONAL FLOW EXIST E OF 70W TO 30W WITH A DOWNSTREAM TROUGH
APPROACHING THE WEST COAST OF AFRICA N OF 12N. A BROAD UPPER
LEVEL RIDGE WAS NOTED S OF 20N W OF 35W WITH THE PARENT HIGH
CENTERED OVER THE TROPICAL E ATLANTIC NEAR 2N41W. A RATHER SHARP
UPPER LEVEL SHORTWAVE TROUGH NEAR 31N46W WILL LIFT NE OVER THE
NEXT 24 HOURS.

$$
COBB






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