[Tropical] Tropical Weather Discussion

[EMWIN Server]

AXNT20 KNHC 090546
TWDAT

TROPICAL WEATHER DISCUSSION
NWS TPC/NATIONAL HURRICANE CENTER MIAMI FL
105 AM EST SAT FEB 09 2008

TROPICAL WEATHER DISCUSSION FOR NORTH AMERICA...CENTRAL
AMERICA...THE GULF OF MEXICO...THE CARIBBEAN SEA...NORTHERN
SECTIONS OF SOUTH AMERICA...AND THE 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 0000 UTC SURFACE ANALYSIS AND SATELLITE IMAGERY THROUGH
0530 UTC.

...THE ITCZ...
THE ITCZ AXIS IS CENTERED ALONG 5N9W 2N20W 2N40W THEN INLAND
OVER SOUTH AMERICA NEAR EQ50W. SCATTERED STRONG CONVECTION IS
FROM 2N TO THE COAST OF LIBERIA. ANOTHER AREA OF SCATTERED
STRONG CONVECTION IS FROM THE EQUATOR TO 5N BETWEEN 16W-20W.
SMALL CLUSTERS OF SCATTERED MODERATE CONVECTION ARE NOTED
ELSEWHERE WITHIN 120 NM OF THE AXIS BETWEEN 20W-30W AND BETWEEN
35W-42W.

...DISCUSSION...

GULF OF MEXICO...
RESIDUAL EFFECTS OF AN UPPER LEVEL SHEARED TROUGH EXITING THE
ERN U.S. AND OVER THE N-CENTRAL ATLC ARE CONFINED TO THE FAR SE
PORTION OF THE GULF OF MEXICO. THIS IS PROVIDING LIMITED SUPPORT
FOR A STATIONARY FRONT EXTENDING FROM 31N72W SOUTHWESTWARD
ACROSS THE FLORIDA PENINSULA NEAR LAKE OKEECHOBEE THEN
CONTINUING ALONG 24N87W AND DISSIPATING FROM THERE INTO THE BAY
OF CAMPECHE NEAR 21N94W. WIDELY SCATTERED SHOWERS ARE OCCURRING
JUST OFF THE FLORIDA E COAST WITHIN 60 NM EITHER SIDE OF THE
FRONT. PATCHES OF BROKEN LOW CLOUDS COMPRISE THE BULK OF THE
FRONT OVER THE GULF OF MEXICO. ANOTHER UPPER LEVEL SHORTWAVE
TROUGH IS MOVING ACROSS THE MISSOURI RIVER VALLEY AND EXTENDS
SOUTHWARD INTO ERN TEXAS AND WILL MOVE ACROSS THE SE CONUS OVER
THE WEEKEND. A BROAD AREA OF SWLY UPPER LEVEL WINDS ARE NOTED
OVER THE ENTIRE GULF BETWEEN THE TROUGH AND AN UPPER RIDGE IN
THE CARIBBEAN EXTENDING NEWD INTO THE W ATLC. STRONG SW WINDS
ALOFT WERE ADVECTING SOME HIGH LEVEL MOISTURE ACROSS THE GULF
STATES. THE STATIONARY FRONT IS EXPECTED TO DISSIPATE LATER
TODAY. HIGH PRESSURE WILL BUILD ACROSS GULF THROUGH TONIGHT AND
STRENGTHEN SUN/MON THEN MOVE E OF THE AREA TUE.

CARIBBEAN SEA...
A PERSISTENT UPPER LEVEL RIDGE EXTENDS FROM THE SW CARIBBEAN
ALONG 80W NEWD ACROSS EASTERN CUBA...THE BAHAMAS AND NE ACROSS
THE SUBTROPICAL ATLC. A SHEARED UPPER TROUGH AXIS EXTENDS WSWWD
ACROSS THE TROPICAL ATLC ACROSS THE NORTHEAST WINDWARD ISLANDS
TO A DIFFUSE CYCLONIC CIRCULATION JUST S OF HISPANIOLA AND THE
MONA PASSAGE. THE SURFACE RIDGE OVER THE ATLC COUPLED WITH THE
LOWER PRESSURE OVER SOUTH AMERICA IS PRODUCING A RATHER TIGHT
PRESSURE GRADIENT OVER THE CARIBBEAN AND IS GENERATING MODERATE
TO STRONG EASTERLY TRADE WINDS ACROSS THE AREA. THE EDGE OF THIS
EVENINGS QUIKSCAT PASS INDICATED 25 KT WINDS ALONG THE COAST OF
COLOMBIA/VENEZUELA. MODERATE/STRONG SUBSIDENCE AND DRY AIR UPPER
AIR ARE LIMITING ANY AREAS OF DEEP CONVECTION ACROSS THE AREA.
HOWEVER...THE STRONG TRADE WINDS ARE USHERING IN SOME LOW LEVEL
CLOUDS WITH SOME LOW LEVEL CONVERGENCE MANIFESTING ITSELF IN A
PATCH OF SCATTERED SHOWERS IN THE VICINITY OF THE CAYMAN
ISLANDS.

ATLANTIC OCEAN...
THE SHEARED UPPER LEVEL TROUGH OVER THE NE US AND N-CENTRAL
ATLC HAS VIRTUALLY DISAPPEARED IN THE WAKE OF AN EXPANSIVE RIDGE
COVERING A MAJORITY OF THE ATLC. THE ONLY MANIFESTATION OF THE
SHEARED TROUGH IS A STATIONARY FRONT EXTENDING FROM 31N72W TO
THE FLORIDA E COAST NEAR STUART. SCATTERED SHOWERS/ISOLATED
THUNDERSTORMS ARE WITHIN 60 NM OF THE FRONT JUST OFF THE FLORIDA
COAST. THE FRONT WILL WEAKEN THE DAY TODAY AS A SECOND COLD
FRONT IS FORECAST TO MOVE OFF THE SE US COAST TONIGHT. STRONG
HIGH PRESSURE WILL BUILD SE ACROSS THE W ATLC BEHIND THE SECOND
FRONT THROUGH TUE INCREASING WINDS OVER THE AREA. THE EXPANSIVE
RIDGE NOTED ABOVE DOMINATES THE CENTRAL ATLC BETWEEN 35W AND
75W. AN UPPER LEVEL ANTICYCLONE WAS NOTED NEAR 27N55W WITH THE
SURFACE RIDGE ANCHORED BY A 1025 MB HIGH NEAR 28N50W. UPPER
LEVEL LOW OVER THE NE ATLC NEAR THE CANARY ISLANDS/28N18W IS
MOVING E 15 KT. STRONGLY POSITIVE TILT TROUGH EXTENDS FROM THE
LOW WSWWD ACROSS 22N30W 18N40W THEN TRANSITIONS TO A SHEAR AXIS
WHICH UNDERCUTS THE STRONG ATLC RIDGE ALONG 19N50W TO THE NE
WINDWARD ISLANDS. AN ASSOCIATED SURFACE TROUGH EXTENDS FROM A
1009 MB LOW NEAR 28N21W JUST W OF THE WESTERNMOST CANARY ISLANDS
TO 22N20W. SCATTERED SHOWERS AND ISOLATED THUNDERSTORMS ARE
NOTED OVER THE CANARY ISLANDS FROM 27N-30N BETWEEN 16W-20W. AN
E/W UPPER RIDGE EXTENDS ACROSS THE TROPICAL ATLC ALONG 5N TO
35W. A STRONG UPPER LEVEL JETSTREAM WITH WINDS OF 90-140 KT CUTS
ALONG THE N PERIPHERY OF THE RIDGE WITHIN 120 NM OF LINE FROM
15N35W TO INLAND OVER W AFRICA/MAURITANIA NEAR 20N16W.

$$
COBB


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