[Tropical] Tropical Weather Discussion

[EMWIN Server]

AXNT20 KNHC 160509
TWDAT

TROPICAL WEATHER DISCUSSION...
NWS TPC/NATIONAL HURRICANE CENTER MIAMI FL
205 AM EDT WED APR 16 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
0430 UTC.

...THE ITCZ...

ITCZ AXIS IS CENTERED ALONG 6N9W 4N20W 1N30W CROSSING THE
EQUATOR NEAR 37W TO 1S48W. SCATTERED MODERATE TO STRONG
CONVECTION IS WITHIN 90 NM N OF THE AXIS BETWEEN 16W-19W AND
WITHIN 130 NM N OF THE AXIS BETWEEN 20W-29W. SCATTERED MODERATE
CONVECTION IS FROM THE EQUATOR TO 2N BETWEEN 44W AND THE NE
COAST OF BRAZIL.

...DISCUSSION...

GULF OF MEXICO...
SATELLITE IMAGERY CONTINUES TO DISPLAY STRATOCUMULUS CLOUDS
SCATTERED ACROSS THE GULF S OF 29N AND E OF 91W. THIS IS
INDICATIVE OF THE UNUSUALLY COLD AND STABLE AIRMASS THAT IS LEFT
OVER FROM THE PASSAGE OF TWO COLD FRONTS EARLIER THIS WEEK. AS
OF 03Z...A 1025 MB SFC HIGH WAS CENTERED IN THE NW GULF NEAR
27N93W. E TO SE RETURN FLOW AROUND THE WEAK SFC RIDGE HAS BEGUN
TO MODIFY THE AIRMASS IN THE WRN WATERS. ALOFT...CONFLUENCE AT
THE BASE OF AN AMPLIFIED TROUGH OVER THE E CONUS/W ATLC IS
CREATING STRONG SUBSIDENCE AND A VERY DRY AIRMASS OVER THE GULF
NE OF A LINE FROM HOUSTON TO THE FLORIDA STRAIGHTS. NEAR ZONAL
FLOW TO THE SOUTH IS ADVECTING UPPER-LEVEL MOISTURE ACROSS THE
SW GULF.

CARIBBEAN SEA...
THE WEATHER PATTERN IN THE NW CARIBBEAN CONTINUES TO BE DICTATED
BY THE PRESENCE OF TWO COLD FRONTS. AS OF 03Z...THE
LEADING...AND WEAKER...FRONT EXTENDS FROM THE WINDWARD PASSAGE
ACROSS THE SE TIP OF JAMAICA TO THE NICARAGUA/HONDURAS BORDER.
THIS FRONT IS EXPECTED TO BE TAKEN OVER BY THE SECONDARY
SURGE...WHICH CURRENTLY EXTENDS FROM CUBA NEAR 21N78W TO
BELIZE NEAR 17N88W...LATER TODAY. BOTH OF THESE BOUNDARIES ARE
DRY IN NATURE WITH ONLY SCATTERED CLOUDS ALONG THEM. THE SFC
TROUGH THAT HAS BEEN TRAVERSING THE CARIBBEAN HAS MADE ITS WAY
TO THE SW PORTION AND...AS OF 03Z...IS DEPICTED ALONG 79W FROM
THE COAST OF PANAMA TO 14N. SCATTERED SHOWERS ARE WITHIN 60 NM
EITHER SIDE OF THE TROUGH. EASTERLY TRADES DOMINATE THE
REMAINDER OF THE CARIBBEAN USHERING IN PATCHY CLOUDS AND
ISOLATED LOW-TOPPED SHOWERS. ALOFT...A WEAK UPPER HIGH IS
SITUATED OFF THE E COAST OF NICARAGUA WHILE TROUGHING LIES OVER
THE ERN CARIBBEAN INDUCED BY AN UPPER LOW NEAR 20N56W. THIS
PATTERN IS CREATING A MODESTLY DRY ENVIRONMENT.

ATLANTIC OCEAN...
A COMPLEX SFC LOW PRESSURE SYSTEM DOMINATES THE W ATLC. AS OF
03Z...THE 1006 MB LOW PRESSURE CENTER WAS LOCATED NEAR 29N77W.
SFC TROUGHING ENTERS THE REGION NEAR 31N74W AND CONTINUES
THROUGH THE LOW CENTER TO THE CENTRAL FLORIDA COAST NEAR
MELBOURNE. NUMEROUS SHOWERS AND THUNDERSTORMS SURROUND THE LOW N
OF 26N W OF 72W. THE TIGHT PRESSURE GRADIENT BETWEEN THE LOW AND
HIGH PRES OVER THE SRN CONUS IS PRODUCING NLY GALE FORCE WINDS
WITHIN 210 NM OF THE LOW. THIS LOW IS EXPECTED TO TRACK N OF THE
AREA...ALLOWING THE GALE CONDITIONS TO END IN ABOUT 12 HOURS. TO
THE EAST...TWO COLD FRONTS REMAIN. AS OF 03Z...THE LEADING
BOUNDARY ENTERS THE W ATLC NEAR 31N63W AND EXTENDS SW ALONG
22N70W TO NEAR 20N73W. A THIN BAND OF LOW LEVEL CLOUDS EXTENDS
ALONG THE BOUNDARY WITH SCATTERED SHOWERS AND THUNDERSTORMS N OF
22N. THE SECOND BOUNDARY EXTENDS FROM 31N66W ALONG 36N70W TO
21N76W. LITTLE THUNDERSTORM ACTIVITY IS ASSOCIATED WITH THIS
SECOND BOUNDARY...HOWEVER LOW LEVEL CLOUDS AND SCATTERED SHOWERS
COVER THE AREA BETWEEN THE TWO FRONTS. THE LEADING FRONT IS SLOW
MOVING AND IS EXPECTED TO MERGE WITH THE SECONDARY SURGE LATER
TODAY. SCATTERED SHOWERS AND THUNDERSTORMS ARE DEVELOPING OFF
THE NORTHERN COAST OF HISPANIOLA AS THE LEADING FRONT APPROACHES
THE TERRAIN.

THE CENTRAL AND E ATLC IS RATHER TRANQUIL DUE TO A BROAD DEEP
LAYER HIGH PRES SYSTEM CENTERED NEAR 31N41W. THE 1029 MB SFC
HIGH PRES IS PRODUCING N TO NE 20-25 KT WINDS NEAR THE COAST OF
AFRICA N OF 17N AND 15-20 KT WINDS ACROSS THE REMAINDER OF THE
TROPICS. STRONG WLY UPPER FLOW BETWEEN AN ELONGATED UPPER TROUGH
OVER W AFRICA AND A FLAT UPPER RIDGE OVER THE TROPICS IS
SPREADING A PLUME OF HIGH LEVEL CLOUDINESS S OF 17N.

$$
WADDINGTON





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