[Tropical] Tropical Weather Discussion

[EMWIN Server]

AXNT20 KNHC 122343
TWDAT

TROPICAL WEATHER DISCUSSION
NWS TPC/NATIONAL HURRICANE CENTER MIAMI FL
805 PM EDT SAT APR 12 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 1800 UTC SURFACE ANALYSIS AND SATELLITE IMAGERY THROUGH
2315 UTC.

...ITCZ...
ITCZ AXIS IS CENTERED ALONG 7N12W 2N25W...ALONG THE EQUATOR
BETWEEN 30W AND 40W THEN INLAND OVER NE BRAZIL NEAR 2S48W.
SCATTERED MODERATE TO ISOLATED STRONG CONVECTION IS WITHIN 90 NM
EITHER SIDE OF THE AXIS BETWEEN 31W-40W. CLUSTERS OF MODERATE TO
STRONG CONVECTION ARE THE COAST OF BRAZIL NE OF A LINE FROM
6N43W TO 1N54W. SIMILAR CONVECTION IS OBSERVED INLAND OVER
SIERRA LEONE AND WESTERN GUINEA.

...DISCUSSION...
GULF OF MEXICO...
A MID TO UPPER LEVEL TROUGH EXTENDING FROM THE GREAT LAKES
REGION SW TO CENTRAL TEXAS SUPPORTS A RATHER STRONG COLD FRONT
FOR THIS TIME OF YEAR THAT IS MOVING ACROSS THE GULF OF MEXICO
EARLY THIS EVENING. AS OF 2100 UTC...THE FRONTAL BOUNDARY
STRETCHES FROM N FLORIDA TO THE BAY OF CAMPECHE WHERE IT BECOMES
STATIONARY THEN CONTINUES INLAND OVER MEXICO. A ROPE LINE
DELINEATES THE LEADING EDGE OF THE FRONT MAINLY OVER THE EASTERN
GULF. DOPPLER RADAR INDICATES SCATTERED SHOWERS AND ISOLATED
TSTMS OVER THE FLORIDA PANHANDLE AND SE GEORGIA. AN EARLIER
ASCAT PASS SHOWED NE WINDS OF 20 TO 25 KT BEHIND THE FRONT AND
OVER THE NW QUADRANT OF THE GULF. WINDS ARE EXPECTED TO REACH
MINIMAL GALE FORCE IN THE SW GULF WATERS ON SUN. A WARNING IS
ALREADY IN EFFECT. AHEAD OF THE FRONT...PATCHY CLOUDS ARE FOUND
UNDER THE INFLUENCE OF AN UPPER RIDGE ANCHORED OVER CENTRAL
AMERICA AND STRONG SUBSIDENCE. LIGHT SOUTHERLY RETURN FLOW
AROUND A SFC RIDGE DOMINATES THE EASTERN GULF...BUT EXPECT THE
WINDS TO SHIFT N AND INCREASE FOLLOWING THE FRONTAL PASSAGE. THE
COLD FRONT IS FORECAST BY THE COMPUTER MODELS TO EXIT THE REGION
BY SUN AFTERNOON WHILE HIGH PRES WILL BUILD IN USHERING A MUCH
COOLER AND DRIER AIRMASS.

CARIBBEAN SEA...
STRONG SUBSIDENCE AND DRY STABLE CONDITIONS ALOFT CONTINUE TO
DOMINATE THE CARIBBEAN PREVENTING ANY DEEP CONVECTION FROM
DEVELOPING. PATCHY CLOUDS AND LOW-TOPPED TRADE WIND SHOWERS ARE
MOVING WESTWARD ACROSS THE REGION...PARTICULARLY N OF 14N. UPPER
LEVEL DIVERGENCE IS ENHANCING CONVECTION JUST E OF THE LESSER
ANTILLES CAUSING A FEW SHOWERS TO MOVE OVER THE WINDWARD
ISLANDS. A TROUGH WAS ANALYZED ON THE 18Z SFC MAP WITHIN AROUND
300 NM SE OF TRINIDAD AND TOBAGO ISLANDS. THE POSITION OF THIS
TROUGH WAS BASED ON SATELLITE IMAGERY AND AN EARLIER ASCAT PASS.
MOISTURE ASSOCIATED WITH THIS TROUGH WILL CONTINUE TO AFFECT THE
WINDWARD ISLANDS AND NE VENEZUELA ON SUN. A DIFFLUENT PATTERN
ALOFT IS ENHANCING SCATTERED MODERATE TO ISOLATED STRONG
CONVECTION OVER NORTHERN CENTRAL AMERICA ESPECIALLY OVER PARTS
OF GUATEMALA AND WESTERN HONDURAS. BRISK EASTERLY TRADE WINDS
PERSIST ACROSS MUCH OF THE CARIBBEAN...WITH THE STRONGEST WINDS
OF 20 TO 25 KT JUST OFFSHORE THE COLOMBIAN COAST. EXPECT THE
COLD FRONT IN THE GULF OF MEXICO TO ENTER THE NW CARIBBEAN BY
LATE SUN.

ATLANTIC OCEAN...
FAIR CONDITIONS PREVAILS OVER THE WESTERN ATLC THANKS TO THE
PRESENCE OF A 1022 MB SFC HIGH CENTERED NEAR 31N60W. A SECOND...
BUT WEAKER SFC HIGH IS FARTHER EAST NEAR 29N49W. EXPECT THESE
TWO FEATURES TO MERGE WITHIN THE NEXT 24 HOURS. A COLD FRONT
OVER THE EASTERN SEABOARD WILL MOVE OFFSHORE GEORGIA AND INTO
THE W ATLC LATER TONIGHT. LIGHT TO MODERATE SOUTHERLY WINDS WILL
INCREASE AND SHIFT NW FOLLOWING THE FRONTAL PASSAGE. IN THE
CENTRAL ATLC...A COLD FRONT ENTERS THE REGION NEAR 31N34W THEN
CONTINUES SW TO NEAR 25N47W. A SURFACE RIDGE ANCHORED BY A 1027
MB HIGH N OF THE REGION COVERS THE EASTERN ATLC. TIGHT PRES
GRADIENT BETWEEN THIS ANTICYCLONE AND LOWER PRES OVER AFRICA IS
PRODUCING A SWATH OF NE WINDS OF 20 TO 30 KT SE OF LINE FROM
31N14W TO 19N23W. ALOFT...A RIDGE DOMINATES THE W ATLC WHILE AN
UPPER LEVEL TROUGH EXTENDS ACROSS THE CENTRAL ATLC ENTERING THE
CARIBBEAN SEA THROUGH THE LEEWARD ISLANDS. SWLY FLOW...BETWEEN
THIS TROUGH AND A RIDGE COVERING THE DEEP TROPICS...ADVECTS
UPPER-LEVEL MOISTURE/HIGH CLOUDS ACROSS THE N TROPICAL ATLANTIC
FROM SOUTH AMERICA TO THE NW COAST OF AFRICA.

$$
GR






This weather bulletin was brought to you by:
www.nashvilleweather.net