[Tropical] Tropical Weather Discussion

[EMWIN Server]

AXNT20 KNHC 182341
TWDAT

TROPICAL WEATHER DISCUSSION
NWS TPC/NATIONAL HURRICANE CENTER MIAMI FL
705 PM EST WED FEB 18 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 5N9W 1N20W CROSSING THE EQUATOR
NEAR 38W THEN INTO NE BRAZIL NEAR 2S45W. ISOLATED MODERATE
CONVECTION IS FROM THE EQUATOR TO 3N BETWEEN 9W-13W. SIMILAR
CONVECTION IS WITHIN 150 NM N OF THE AXIS BETWEEN 18W-25W.
SCATTERED MODERATE/ISOLATED STRONG CONVECTION IS WITHIN 120 NM
OFFSHORE THE COAST OF BRAZIL BETWEEN 46W-50W.

...DISCUSSION...

GULF OF MEXICO...
A 1022 MB SURFACE HIGH IN THE W ATLC EXTENDS A RIDGE ACROSS THE
FLORIDA PENINSULA AND SRN GULF OF MEXICO PRODUCING MOSTLY FAIR
WEATHER S OF 27N. SCATTERED MULTI-LAYERED CLOUDS WITH EMBEDDED
ISOLATED SHOWERS ARE OBSERVED OVER THE NRN GULF WATERS AS
SOUTHERLY RETURN FLOW OF UP TO 20 KT IS ESTABLISHED AHEAD OF A
COLD FRONT DRAPED ACROSS THE TEXAS GULF COAST. THIS FRONT IS
FORECAST TO MOVE INTO THE NW GULF THIS EVENING ALLOWING STRONG
N-NE WINDS TO FOLLOW THE FRONTAL PASSAGE THROUGH THE DAY THURS.
IN THE UPPER LEVELS...STRONG WNW FLOW AROUND AN UPPER RIDGE WITH
AXIS ALONG 100W IS TRANSPORTING UPPER LEVEL MOISTURE ACROSS THE
NRN GULF WATERS WHILE THE SRN GULF...INCLUDING SE MEXICO AND THE
YUCATAN PENINSULA REMAINS RELATIVELY CLEAR UNDER MODERATE TO
STRONG SUBSIDENCE.

CARIBBEAN SEA...
THE TAIL END OF A COLD FRONT EXTENDING FROM THE CENTRAL ATLC IS
OVER THE GUADELOUPE PASSAGE WITH BROKEN LOW/MID CLOUDS AND
ISOLATED SHOWERS. THE FRONTAL REMNANTS ARE EXPECTED TO BECOME
MORE DIFFUSE ACROSS THE NE CARIBBEAN AND LEEWARD ISLANDS THROUGH
THU. LOW-LEVEL CONVERGENCE OF FRESH TO STRONG EASTERLY TRADES
ACROSS THE CENTRAL AND WRN CARIBBEAN ARE GENERATING ISOLATED
SHOWERS WITHIN 60 NM OF A LINE FROM 15N70W TO 12N81W. HOWEVER...
THESE SHALLOW SHOWERS REMAIN UNDER STRONG SUBSIDENCE IN THE MID
TO UPPER LEVELS ACROSS MUCH OF THE BASIN. THE HIGHER PRESSURE
ACROSS THE W ATLC WILL MAINTAIN STRONG TRADE WIND FLOW ACROSS
THE CARIBBEAN THROUGH THU WITH THE NEXT COLD FRONT FORECAST TO
REACH WRN CUBA AND THE NW CARIBBEAN EARLY FRIDAY.

ATLANTIC OCEAN...
A DEEP LAYERED TROUGH IS ACROSS THE NW ATLC AND SUPPORTS A COLD
FRONT THAT ENTERS THE DISCUSSION AREA NEAR 32N46W AND CONTINUES
SW TO GUADELOUPE. A BAND OF MULTI-LEVEL CLOUDS AND SCATTERED
SHOWERS IS NOTED WITHIN 200 NM E OF THE FRONT N OF 26N AND
WITHIN 120 NM E OF THE FRONT ALONG THE REMAINDER OF THE BOUNDARY
TO THE LEEWARD ISLANDS. A SECOND BAND OF LOW CLOUDS AND EMBEDDED
SHOWERS SURROUNDS A PRE-FRONTAL TROUGH ANALYZED FROM 21N52W TO
15N53W. COLD AIR STRATOCUMULUS CLOUDS AROUND A 1022 MB SURFACE
HIGH NEAR 29N70W COVER THE W ATLC AND THE BAHAMAS BEHIND THE
FRONTAL ZONE. E OF THE FRONT...A SURFACE RIDGE EXTENDS FROM A
1030 MB HIGH NEAR 32N25W PROVIDING FAIR WEATHER ACROSS THE E
ATLC. THE SRN PERIPHERY OF THIS RIDGE IS ALSO PRODUCING A LARGE
AREA OF MODERATE TO FRESH TRADE WINDS ACROSS THE TROPICS MAINLY
EAST OF 45W. ALOFT...A HIGHLY AMPLIFIED TROUGH/RIDGE/TROUGH
PATTERN DOMINATES THE ATLC OCEAN BASIN. THE DEEP LAYERED TROUGH
OVER THE W ATLC SUPPORTS THE AFOREMENTIONED COLD FRONT WHILE A
SHARP RIDGE EXTENDS OVER THE CENTRAL ATLC ALONG 36W TO BEYOND
THE AZORES. E OF THE RIDGE...ANOTHER DEEP LAYERED TROUGH WITH
UPPER LOW NEAR 30N13W STRETCHES FROM THE CANARY ISLANDS TO THE
CAPE VERDE ISLANDS.

$$
HUFFMAN




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