[Tropical] Tropical Weather Discussion

[EMWIN Server]

AXNT20 KNHC 180544
TWDAT

TROPICAL WEATHER DISCUSSION
NWS NATIONAL HURRICANE CENTER MIAMI FL
105 AM EST FRI SAT 18 2012

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...WEATHER OBSERVATIONS...RADAR...AND METEOROLOGICAL
ANALYSIS.

BASED ON 0000 UTC SURFACE ANALYSIS AND SATELLITE IMAGERY THROUGH
0500 UTC.

...ITCZ/MONSOON TROUGH...

THE MONSOON TROUGH EXTENDS ACROSS W AFRICA TO THE COAST OF
SIERRA LEONE NEAR 8N13W TO 4N17W. THE ITCZ CONTINUES FROM 4N17W
CROSSING THE EQUATOR AT 27W CONTINUING TO THE COAST OF BRAZIL
NEAR 5S36W. SCATTERED MODERATE/STRONG CONVECTION IS FROM 1N-4N
BETWEEN 21W-31W...AND FROM 2N-6N BETWEEN 32W-40W.

...DISCUSSION...

GULF OF MEXICO...
UPPER LEVEL RIDGING CONTINUES TO COVER THE GULF OF MEXICO
TONIGHT WITH AXIS EXTENDING FROM CENTRAL AMERICA. THIS PATTERN
IS DRAWING UPPER LEVEL MOISTURE ACROSS CENTRAL MEXICO AND THE
NRN GULF. HOWEVER...A SHORTWAVE UPPER TROUGH IS MOVING ACROSS SE
TEXAS SUPPORTING STRONG SHOWERS/THUNDERSTORMS NEAR A STATIONARY
FRONT THAT DRAPES ACROSS THE NRN GULF. THE FRONT EXTENDS FROM
NRN FLORIDA NEAR 29N83W TO TEXAS ALONG 28N90W 28N97W 26N98W. AS
OF 0300 UTC...THE ERN PORTION OF THE FRONT HAS BEGUN TO
DISSIPATE. RADAR IMAGERY INDICATES THE STRONGEST
SHOWER/THUNDERSTORM ACTIVITY IS S OF WRN LOUISIANA FROM 28N-29N
BETWEEN 93W-96W. SCATTERED SHOWERS ARE ALSO N OF 26N W OF 91W
WITH A FEW ISOLATED SHOWERS ACROSS THE ERN GULF FROM 27N-29N E
OF 85W. A LONGWAVE UPPER TROUGH CURRENTLY OVER ARIZONA IS
EXPECTED TO MOVE EWD OVER THE NEXT COUPLE OF DAYS. DURING THE
NEXT 6-12 HOURS AS THE LONGWAVE MOVES E...A SURFACE LOW IS
EXPECTED TO FORM ALONG THE TEXAS COAST. THE LOW IS EXPECTED TO
MOVE NE PUSHING A COLD FRONT ACROSS THE GULF OF MEXICO. STRONG
WINDS ARE EXPECTED BEHIND THE FRONT WITH LIKELY
SHOWER/THUNDERSTORM ACTIVITY ALONG IT.

CARIBBEAN SEA...
UPPER LEVEL RIDGING COVERS THE FAR WRN CARIBBEAN WITH AXIS UP
CENTRAL AMERICA ALONG 86W. AN UPPER LEVEL TROUGH COVERS THE ERN
CARIBBEAN EXTENDING FROM THE LEEWARD ISLANDS TO THE SW CARIBBEAN
DUE TO STRONG DRY AIR ALOFT ACROSS THE BASIN SURFACE CONDITIONS
STILL REMAIN FAIR. TRADEWIND FLOW OF 15-20 KTS IS PRESENT ACROSS
THE ERN CARIBBEAN BECOMING 10-15 KTS ACROSS THE CENTRAL AND NW
CARIBBEAN WITH STRONGER WINDS NEAR THE COAST OF COLOMBIA. A FEW
CLUSTERS OF LOW-LEVEL CLOUDS ARE NOTED S OF JAMAICA AND PUERTO
RICO WITH POSSIBLE ISOLATED SHOWERS. EXPECT LITTLE CHANGE OVER
THE NEXT 24 HOURS. A COLD FRONT EXPECTED TO MOVE ACROSS THE GULF
OF MEXICO THROUGHOUT THE WEEKEND WILL REACH THE NW CARIBBEAN
EARLY MONDAY.

ATLANTIC OCEAN...
BROAD UPPER LEVEL RIDGING EXTENDING FROM THE WRN CARIBBEAN
COVERS THE WRN ATLC SUPPORTING WEAK SURFACE RIDGING AROUND A
1020 MB SURFACE HIGH NEAR 26N66W PROVIDING FAIR WEATHER ACROSS
THE W ATLC S OF 28N. TO THE N...A COLD FRONT ENTERS THE
DISCUSSION AREA NEAR 32N69W CONTINUING TO THE FLORIDA COAST AT
29N81W. SCATTERED SHOWERS ARE WITHIN 120 NM EITHER SIDE THE
AXIS. THE FRONT IS SUPPORTED BY A SHORTWAVE UPPER TROUGH TO THE
N ALONG 65W. A WEAK SURFACE TROUGH IS ANALYZED N OF THE LEEWARD
ISLANDS ALONG 23N60W TO 20N63W WITH ISOLATED SHOWERS WITHIN 90
NM EITHER SIDE THE AXIS. ACROSS THE CENTRAL ATLC...A SHARP UPPER
LEVEL TROUGH IS ALONG 45W SUPPORTING A SURFACE TROUGH ALONG
28N47W TO 17N51W. MOST OF THE SHOWER ACTIVITY IS TO THE E WITH
SCATTERED SHOWERS/ISOLATED THUNDERSTORMS N OF 19N BETWEEN
41W-47W. THIS UPPER TROUGH MAY ALSO BE ENHANCING SOME OF THE
CONVECTION N OF THE ITCZ REGION. FARTHER E...AN UPPER LEVEL
RIDGE COVERS THE ERN ATLC WITH AXIS ALONG 27W SUPPORTING A
SURFACE RIDGE ANCHORED BY A 1030 MB AZORES HIGH NEAR 41N24W. THE
RIDGE IS PROVING MOSTLY FAIR WEATHER ACROSS THE FAR ERN ATLC.

FOR ADDITIONAL INFORMATION PLEASE VISIT
HTTP://WWW.HURRICANES.GOV/MARINE

$$

WALTON





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