[Tropical] Tropical Weather Discussion

[EMWIN Server]

AXNT20 KNHC 172338
TWDAT

TROPICAL WEATHER DISCUSSION
NWS TPC/NATIONAL HURRICANE CENTER MIAMI FL
705 PM EST TUE FEB 17 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.

...THE ITCZ...

THE ITCZ AXIS IS CENTERED ALONG 4N8W 1N20W CROSSING THE EQUATOR
AT 38W...AND INTO NE BRAZIL NEAR 2S45W. SCATTERED MODERATE TO
ISOLATED STRONG CONVECTION IS WITHIN 150 NM N OF THE AXIS
BETWEEN 21W-28W AND BETWEEN 32W-39W. SCATTERED MODERATE
CONVECTION IS ALSO WITHIN 150 NM OF THE NE BRAZIL COAST BETWEEN
40W-50W.

...DISCUSSION...

GULF OF MEXICO...
A 1027 MB HIGH OVER SOUTH CAROLINA EXTENDS A RIDGE ACROSS THE
FLORIDA PENINSULA AND GULF OF MEXICO PRODUCING MOSTLY FAIR
WEATHER. SCATTERED MULTI-LAYERED CLOUDS ARE OBSERVED OVER THE
WRN HALF OF THE GULF WHERE SOUTHERLY RETURN FLOW OF UP TO 20 KT
IS ESTABLISHED AHEAD OF A DEVELOPING LOW PRESSURE SYSTEM OVER
THE CENTRAL CONUS. THE HIGH PRESSURE WILL MOVE SE INTO THE W
ATLC OVER THE NEXT 24 HOURS ALLOWING THE NEXT COLD FRONT TO
ENTER THE NW GULF WED AFTERNOON. IN THE UPPER LEVELS...A RIDGE
EXTENDS FROM THE E PACIFIC REGION ACROSS MEXICO AND THE GULF
GENERATING NW FLOW...ALLOWING MODERATE SUBSIDENCE S OF 26N AND
PROMOTING STABLE ATMOSPHERIC CONDITIONS ACROSS THE SRN GULF AND
YUCATAN PENINSULA THIS EVENING.

CARIBBEAN SEA...
THE TAIL END OF A COLD FRONT EXTENDING FROM THE W ATLC IS OVER
NRN HISPANIOLA WITH BROKEN LOW CLOUDS AND ISOLATED SHOWERS
WITHIN 90 NM SE OF THE FRONT. HIGH PRESSURE NW OF THE COLD
FRONT...CENTERED OVER SOUTH CAROLINA...COVERS CUBA AND THE NW
CARIBBEAN. NE WINDS AROUND THE SRN PERIPHERY OF THIS HIGH ARE
TRANSPORTING SCATTERED COLD AIR STRATOCUMULUS CLOUDS FROM THE W
ATLC INTO THE NW CARIBBEAN W OF 75W. FURTHER E...A SURFACE
TROUGH REMAINS OVER THE ERN CARIBBEAN WITH AXIS ALONG 68W/69W S
OF 17N. THIS TROUGH IS GENERATING A LARGE AREA OF LOW/MID CLOUDS
WITH ISOLATED SHOWERS OVER THE ABC ISLANDS. THE TRADE WINDS WILL
START TO INCREASE ACROSS THE BASIN OVER THE NEXT 24 HOURS AS
HIGH PRESSURE OVER THE W ATLC TIGHTENS THE PRESSURE GRADIENT
OVER THE CARIBBEAN. IN THE UPPER LEVELS...A TROUGH IS ACROSS
CENTRAL AMERICA AND THE WRN CARIBBEAN W OF 80W WHILE A RIDGE
EXTENDS FROM THE WRN TROPICAL ATLC ACROSS THE ERN AND CENTRAL
CARIBBEAN TO 80W. STRONG SUBSIDENCE IS NOTED OVER THE WRN
CARIBBEAN W OF 75W.

ATLANTIC OCEAN...
A VERY STRONG EXTRATROPICAL CYCLONE WITH HURRICANE FORCE WINDS
IN THE WRN SEMICIRCLE IS SPINNING OVER THE W-CENTRAL ATLC OCEAN
NEAR 37N58W. THE ATTENDANT COLD FRONT ENTERS THE FORECAST AREA
NEAR 32N52W THEN CONTINUES SW ALONG 23N60W TO 20N70W AND ACROSS
NRN HISPANIOLA. A WELL DEFINED BAND OF LOW/MID CLOUDS WITH
EMBEDDED SHOWERS IS WITHIN 90 NM E OF THE FRONT. THIS SHOWER
ACTIVITY WILL CONTINUE TO IMPACT HISPANIOLA AND PUERTO RICO
THROUGH THE EVENING. THE REMAINDER OF THE ATLC IS UNDER THE
INFLUENCE OF A RIDGE ANCHORED ON A HIGH LOCATED WELL N OF
REGION. THIS HIGH IS GENERATING MOSTLY FAIR WEATHER WITH
MODERATE TO FRESH NE TRADE WINDS NOTED ACROSS THE TROPICS.
ALOFT...AN AMPLIFIED TROUGH/RIDGE/TROUGH PATTERN DOMINATES THE
ATLC OCEAN BASIN. THE DEEP LAYERED TROUGH OVER THE W ATLC
SUPPORTS THE ABOVE MENTIONED COLD FRONT. A RIDGE EXTENDS OVER
THE CENTRAL ATLC TO BEYOND THE AZORES ISLANDS. E OF THE
RIDGE...ANOTHER DEEP LAYERED TROUGH AXIS STRETCHES FROM THE
MADEIRA ISLANDS TO THE CAPE VERDE ISLANDS. W-NW UPPER-LEVEL FLOW
COVERS THE DEEP TROPICS S OF 20N.

$$
HUFFMAN




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