[Tropical] Tropical Weather Discussion

[EMWIN Server]

AXNT20 KNHC 172341
TWDAT

TROPICAL WEATHER DISCUSSION
NWS NATIONAL HURRICANE CENTER MIAMI FL
805 PM EDT WED APR 17 2013

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 1800 UTC SURFACE ANALYSIS AND SATELLITE IMAGERY THROUGH
2245 UTC.

...THE ITCZ/THE MONSOON TROUGH...

THE MONSOON TROUGH PASSES THROUGH COASTAL SENEGAL NEAR 12N16W TO
6N19W 3N22W. THE ITCZ BEGINS AT 3N22W AND CONTINUES ALONG 1N30W
1S35W. SCATTERED MODERATE/ISOLATED STRONG CONVECTION IS FROM 3N-
5N BETWEEN 10W-13W.

...DISCUSSION...

THE GULF OF MEXICO...

MOSTLY FAIR CONDITIONS ARE ACROSS MUCH OF THE GULF OF MEXICO
THIS EVENING ASSOCIATED WITH DRY AIR ALOFT AROUND BROAD UPPER
LEVEL RIDGING. A WEAK UPPER TROUGH IS EMBEDDED WITHIN THE LARGER
SCALE UPPER RIDGE WITH AXIS ALONG 88W. SOME UPPER LEVEL MOISTURE
IS STREAMING AROUND THE EAST SIDE OF THE UPPER TROUGH PROVIDING
HIGH CLOUD COVER ACROSS THE EASTERN GULF. RADAR IMAGERY ONLY
INDICATES A FEW AREAS OF ISOLATED SHOWERS ALONG THE SW FLORIDA
COAST. AT THE SURFACE...BROAD RIDGING CONTINUES EXTENDING FROM A
1023 MB HIGH OVER EASTERN TENNESSEE. THIS PATTERN IS PROVIDING
EAST TO SOUTHEAST WINDS RANGING FROM 15-20 KT. LITTLE CHANGE IS
EXPECTED OVER THE NEXT 24 HOURS. THEN A COLD FRONT IS EXPECTED
TO MOVE OFF THE TEXAS COAST LAST THURSDAY OR EARLY FRIDAY.

THE CARIBBEAN SEA...

AN UPPER LEVEL RIDGE WITH AXIS ALONG 80W COVERS THE CARIBBEAN
PROVIDING DRY AIR ALOFT ACROSS THE AREA. THIS SUPPORTS MOSTLY
CLEAR SKIES THROUGHOUT EXCEPT FOR A FEW ISOLATED
SHOWERS/THUNDERSTORMS ACROSS THE NORTHERN ISLANDS INCLUDING
CUBA...JAMAICA...HISPANIOLA...AND PUERTO RICO. MORE SCATTERED
ACTIVITY IS ACROSS THE NORTHERN LEEWARD ISLANDS ASSOCIATED WITH
A SMALL AREA OF LOW-LEVEL MOISTURE PRESENT IN TOTAL PRECIPITABLE
WATER IMAGERY. TRADEWIND FLOW OF 15-20 KT BLOWS THROUGHOUT MUCH
OF THE EASTERN AND CENTRAL CARIBBEAN REACHING 25 KT NEAR THE
COAST OF COLOMBIA. LITTLE CHANGE IS EXPECTED OVER THE NEXT 24
HOURS. SHOWERS/POSSIBLE THUNDERSTORMS ARE LIKELY TO REMAIN
ACROSS THE NORTHERN LEEWARD ISLANDS.

THE ATLANTIC OCEAN...

THE UPPER LEVEL RIDGE ALONG 80W CONTINUES UP THE EASTERN
SEABOARD. AN UPPER LEVEL TROUGH TO THE EAST CONTINUES TO SUPPORT
A PAIR OF WEAK 1019 MB SURFACE LOWS NEAR 29N76W AND 30N69W. A
SURFACE TROUGH EXTENDS FROM THE WESTWARD LOW ALONG 29N74W 26N76W
25N80W. WIDELY ISOLATED SHOWERS ARE ALONG THE TROUGH AXIS. A
DISSIPATING COLD FRONT IS EAST OF THE EASTWARD LOW ALONG 31N66W
TO 30N67W. IT CONNECTS TO A DISSIPATING OCCLUDED FRONT THAT
WRAPS INTO THE LOW CENTER. THE LOWS ARE EXPECTED TO DISSIPATE
WITHIN THE NEXT 24 HOURS. THE UPPER TROUGH SUPPORTING THE SYSTEM
CONTINUES INTO THE NE ATLC. IT ALSO SUPPORTS A FRONTAL BOUNDARY
THAT SPREADS FROM NEAR NORTHERN PORTUGAL TO A WEAK FRONTAL LOW
NEAR 32N39W. A COLD FRONT EXTENDS FROM THE LOW CENTER TO NEAR
27N55W WHERE IT BECOMES A DISSIPATING STATIONARY FRONT AND
CONNECTS INTO THE AFOREMENTIONED OCCLUDED LOW IN THE WEST ATLC.
ISOLATED SHOWERS ARE WITHIN 100 NM NORTH OF THE COLD FRONT. AN
AREA OF SHOWERS AND POSSIBLE THUNDERSTORMS REMAINS NEAR THE
NORTHERN LEEWARD ISLANDS FROM 15N-19N BETWEEN 55W-62W ASSOCIATED
WITH AN AREA OF ENHANCED LOW-LEVEL MOISTURE PRESENT IN TOTAL
PRECIPITABLE WATER IMAGERY. THE REMAINDER OF THE EAST ATLC IS
COVERED BY WEAK SURFACE RIDGING. BROAD UPPER RIDGING ALONG 21W
SUPPORTS THE SURFACE HIGH PRESSURE.

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

$$
WALTON

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