[Tropical] Tropical Weather Discussion

[EMWIN Server]

AXNT20 KNHC 162348
TWDAT

TROPICAL WEATHER DISCUSSION
NWS TPC/NATIONAL HURRICANE CENTER MIAMI FL
705 PM EST FRI JAN 16 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 7N13W 3N20W 2N30W 1N40W INTO NE
BRAZIL NEAR 1S45W. SCATTERED MODERATE CONVECTION IS FROM 2N-5N
BETWEEN 13W-20W...AND FROM EQ-3N BETWEEN 30W-41W. SIMILAR
CONVECTION IS NEAR 3N25W.

...DISCUSSION...

THE GULF OF MEXICO...
A 1040 MB HIGH OVER THE EASTERN U.S. EXTENDS A RIDGE ACROSS THE
ENTIRE GULF OF MEXICO AND THE STATE OF FLORIDA. THIS SYSTEM IS
MAINTAINING BELOW NORMAL TEMPERATURES AND NE WINDS OF 20 TO 25
KT...PARTICULARLY OVER THE SE PORTION OF THE AREA. COLD AIR
STRATOCUMULUS CLOUDS ARE NOTED OVER THE GULF REGION DUE TO THE
COLD AIR ADVECTION OVER RELATIVELY WARM WATERS. A BAND OF
TRANSVERSE HIGH CLOUDS IS ALSO SEEN ON SATELLITE IMAGERY
ASSOCIATED WITH STRONG SWLY UPPER-LEVEL WINDS WHICH DOMINATE THE
MAJORITY OF THE GULF. A 110-130 KT JETSTREAM CROSSES THE N GULF
WATERS AND THE SE CONUS THEN CONTINUES INTO THE ATLANTIC OCEAN.
THE HIGH PRESSURE OVER THE EASTERN CONUS WILL CONTINUE TO MOVE
SLOWLY E AND WEAKEN TONIGHT THROUGH SAT WITH WINDS GRADUALLY
DIMINISHING OVERNIGHT ACROSS THE N GULF WATERS. THE NEXT COLD
FRONT IS FORECAST TO MOVE ACROSS THE NW PORTION OF THE GULF ON
SUN.

THE CARIBBEAN SEA...
A MEANDERING FRONT OVER THE NW CARIBBEAN CONTINUES TO GENERATE
ABUNDANT CLOUDINESS WITH SCATTERED SHOWERS. THE FRONT FROM THE
ATLC ENTERS THE CARIBBEAN SEA THROUGH CENTRAL CUBA THEN
CONTINUES SW TO THE COAST OF HONDURAS NEAR 16N87W. AS WAS
PREDICTED BY THE COMPUTER MODELS...A SFC TROUGH HAS ENTERED THE
EASTERN CARIBBEAN EXTENDING FROM THE N LEEWARD ISLANDS TO ISLA
DE MARGARITA VENEZUELA. THE CLOUD PATTERN IS SHOWING SOME
CYCLONIC CIRCULATION ALTHOUGH IS VOID OF ANY DEEP CONVECTION.
SCATTERED SHOWERS ASSOCIATED WITH THIS TROUGH ARE ALREADY
REACHING THE NE SECTOR OF PUERTO RICO AS SEEN ON THE SAN JUAN
DOPPLER RADAR. OTHER SHOWERS ARE OVER THE VIRGIN ISLANDS AND
COASTAL WATERS. MOISTURE ASSOCIATED WITH THIS FEATURE WILL
CONTINUE TO SPREAD OVER THE NE CARIBBEAN TONIGHT AND SAT...AND
MAY REACH THE DOMINICAN REPUBLIC ON SUN KEEPING THE ENVIRONMENT
HUMID AND UNSTABLE WITH THE RISK OF MORE SHOWERS. THIS TROUGH IS
EXPECTED TO BECOME DIFFUSE OVER THE CENTRAL CARIBBEAN NEAR 75W
ON MON. MODERATE TO STRONG TRADE WINDS ARE BLOWING ACROSS THE
BASIN WHILE NE WINDS OF 20 TO 25 KT ARE NOTED BEHIND THE ABOVE
MENTIONED STATIONARY FRONT. ALOFT...A RIDGE ANCHORED BY A HIGH
LOCATED OVER THE CENTRAL CARIBBEAN NEAR 15N70W DOMINATES MUCH OF
THE CARIBBEAN. AN UPPER-LOW SPINNING OVER THE TROPICAL CENTRAL
ATLC NEAR 16N55W CLIPS THE LESSER ANTILLES AND THE FAR E
CARIBBEAN.

THE ATLANTIC OCEAN...
A DEEP-LAYERED TROUGH OVER THE EASTERN U.S. SUPPORTS A
STATIONARY FRONT THAT ENTERS THE FORECAST AREA NEAR 32N60W THEN
CONTINUES SW CROSSING THE CENTRAL BAHAMAS AND CENTRAL CUBA INTO
THE NW CARIBBEAN. A BAND OF MULTILAYERED CLOUDS WITH EMBEDDED
SHOWERS IS RELATED TO THE FRONT. THE REMAINDER OF THE DISCUSSION
AREA REMAINS UNDER THE INFLUENCE OF A SFC RIDGE ANCHORED ON A
1033 MB HIGH LOCATED NEAR 32N34W. A SWATH OF MODERATE TO STRONG
TRADE WINDS OF 20 TO 25 KT IS ON THE SOUTHERN PERIPHERY OF THIS
RIDGE AFFECTING THE TROPICS. THIS SYNOPTIC PATTERN WILL REMAIN
UNCHANGED DURING THE NEXT 24 HOURS OR SO. ALOFT...A RIDGE
EXTENDS FROM THE CARIBBEAN SEA THROUGH HISPANIOLA AND PUERTO
RICO INTO THE CENTRAL AND EASTERN ATLANTIC WITH AN UPPER-LEVEL
HIGH SITUATED NEAR 28N44W. SOUTH OF THE RIDGE...THE
AFOREMENTIONED UPPER-LEVEL LOW. STRONG NLY UPPER-LEVEL WINDS OF
110-130 KT ARE OVER THE MADEIRA/CANARY ISLANDS BEHIND AN
UPPER-LEVEL TROUGH WHICH STRETCHES FROM AN UPPER-LEVEL LOW OVER
N MOROCCO TO THE CAPE VERDE ISLANDS. THIS UPPER FEATURE
CONTINUES MAINLY WWD ACROSS THE OCEAN TO THE UPPER LOW LOCATED E
OF THE LESSER ANTILLES. SUBSIDENCE AND ASSOCIATED DRY AIR IS
ALONG THE TROUGH AXIS.

$$
GR





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