[Tropical] Tropical Weather Discussion

[EMWIN Server]

AXNT20 KNHC 090549
TWDAT

TROPICAL WEATHER DISCUSSION
NWS NATIONAL HURRICANE CENTER MIAMI FL
205 AM EDT TUE JUL 09 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 0000 UTC SURFACE ANALYSIS AND SATELLITE IMAGERY THROUGH
0445 UTC.

...SPECIAL FEATURES...
AS OF 0600 UTC...TROPICAL STORM CHANTAL IS CENTERED NEAR 12.9N
57.2W...OR ABOUT 135 NM E OF BARBADOS MOVING WNW NEAR 23 KT.
ESTIMATED MINIMUM CENTRAL PRESSURE IS 1010 MB. MAXIMUM SUSTAINED
WIND SPEED IS 45 KT WITH GUSTS TO 55 KT. SEE LATEST NHC
INTERMEDIATE PUBLIC ADVISORY UNDER AWIPS/WMO HEADERS
MIATCPAT3/WTNT33 KNHC AND THE FULL FORECAST/ADVISORY UNDER
AWIPS/WMO HEADERS MIATCMAT3/WTNT23 KNHC FOR MORE DETAILS. ON THE
CURRENT TRACK...CHANTAL IS EXPECTED TO REACH THE LESSER ANTILLES
LATER THIS MORNING. TOTAL RAIN ACCUMULATIONS OF 2-4 INCHES ARE
EXPECTED WITH MAXIMUM OF 6 INCHES POSSIBLE. CURRENTLY NUMEROUS
STRONG CONVECTION IS NEAR THE STORM CENTER FROM 12N-13N BETWEEN
55W-57W. SCATTERED MODERATE CONVECTION IS ELSEWHERE FROM 11N-14N
BETWEEN 53W-59W. ISOLATED MODERATE CONVECTION IS FROM 14N-17N
BETWEEN 52W-56W.

...TROPICAL WAVES...
TROPICAL WAVE IS JUST OFF THE COAST OF AFRICA FROM 16N19W TO
7N17W MOVING WEST AT 5 KT. THE WAVE ALIGNS WITH A MAXIMUM
MOISTURE SIGNAL IN TOTAL PRECIPITABLE WATER IMAGERY. SCATTERED
MODERATE/ISOLATED STRONG CONVECTION IS FROM 7N-13N BETWEEN 14W-
24W.

TROPICAL WAVE IS ALONG 11N29W TO 4N28W MOVING WEST NEAR 10-15
KT. THE WAVE ALIGNS WITH A LOW-AMPLITUDE 700 MB TROUGH.
SCATTERED MODERATE/ISOLATED STRONG CONVECTION IS FROM 8N-9N
BETWEEN 26W-28W. A BURST OF SCATTERED MODERATE/STRONG CONVECTION
IS ALSO FARTHER WEST FROM 5N-8N BETWEEN 32W-37W.

TROPICAL WAVE IS ALONG 26N77W TO 15N85W MOVING WEST AT 15-20 KT.
THE WAVE IS ON THE WEST SIDE OF A LARGE AREA OF DEEP LAYER
MOISTURE PRESENT IN TOTAL PRECIPITABLE WATER IMAGERY. THE
NORTHERN PORTION OF THE WAVE IS ALSO UNDER THE INFLUENCE OF AN
UPPER LEVEL LOW CENTERED NEAR 25N77W. IT IS HARD TO DETERMINE
WHICH FEATURE IS CONTRIBUTING TO CONVECTION IN THE AREA.
REGARDLESS...SCATTERED MODERATE/ISOLATED STRONG CONVECTION IS
FROM 21N-23N BETWEEN 70W-74W...AND FROM 26N-29N BETWEEN 71W-76W.
THE NORTHERN PORTION OF THIS WAVE IS EXPECTED TO MOVE NW OVER
FLORIDA WHILE THE SOUTHERN PORTION CONTINUES WEST. FOR THIS
REASON...THE WAVE WILL LIKELY BE SPLIT ON THE NEXT ANALYSIS.

...ITCZ/MONSOON TROUGH...
THE MONSOON TROUGH EXTENDS FROM THE COAST OF GUINEA-BISSAU NEAR
12N16W AND CONTINUES ALONG 7N25W 7N37W. THERE IS NOT AN ITCZ
AXIS AT THIS TIME. CONVECTION NEAR THE AXIS IS ASSOCIATED WITH
TROPICAL WAVES AND IS DISCUSSED IN THE SECTION ABOVE.

...DISCUSSION...

GULF OF MEXICO...
WEAK SURFACE RIDGING IS PRESENT OVER THE GULF OF MEXICO
EXTENDING FROM HIGH PRESSURE OVER THE EASTERN CONUS AND WEST
ATLC. THE AREA IS RELATIVELY CLEAR COMPARED TO PREVIOUS
NIGHTS...BUT TOTAL PRECIPITABLE WATER IMAGERY CONTINUES TO SHOW
INCREASED MOISTURE OVER THE WESTERN HALF OF THE BASIN. EAST TO
SOUTHEAST WIND OF 10-15 KT ARE THROUGHOUT THE AREA. A FEW
ISOLATED SHOWERS/THUNDERSTORMS ARE OFF THE NW COAST OF FLORIDA
AS WELL AS IN THE BAY OF CAMPECHE NEAR A WEAK SURFACE TROUGH
ALONG 21N90W TO 17N92W. ALOFT...PRIMARILY NE FLOW COVERS THE
BASIN. WEAK RIDGING WILL REMAIN THE DOMINANT FEATURE THROUGHOUT
THE GULF EXCEPT FOR THE NORTHERN PORTION OF A TROPICAL WAVE
WHICH IS EXPECTED TO MOVE OVER FLORIDA DURING THE NEXT DAY OR
SO.

CARIBBEAN SEA...
MUCH OF THE CARIBBEAN IS EXPERIENCING FAIR CONDITIONS DESPITE
THE PRESENCE OF A TROPICAL WAVE EXTENDING FROM WESTERN CUBA TO
HONDURAS. SCATTERED SHOWERS/THUNDERSTORMS ARE OVER HAITI LIKELY
ASSOCIATED WITH AN UPPER LEVEL LOW OVER THE BAHAMAS. A FEW
ISOLATED SHOWERS/THUNDERSTORMS ARE ALSO IN THE SW CARIBBEAN
LINKED TO THE MONSOON TROUGH THAT EXTENDS THROUGH PANAMA TO
NORTHERN COLOMBIA. TRADEWIND FLOW OF 15-20 KT IS THROUGHOUT THE
AREA. ALOFT...UPPER TROUGHING CONNECTED TO THE UPPER LOW OVER
THE BAHAMAS IS PRESENT OVER THE FAR NW CARIBBEAN...BUT IS
ACCOMPANIED BY DRY AIR. THE REMAINDER OF THE BASIN IS COVERED BY
BROAD UPPER RIDGING CENTERED NEAR 14N80W. THE FAIR CONDITIONS
WILL BEGIN TO DETERIORATE OVER THE EASTERN CARIBBEAN SHORTLY AS
TROPICAL STORM CHANTAL APPROACHES FROM THE EAST. THE STORM IS
EXPECTED TO REACH THE LESSER ANTILLES LATER THIS MORNING AND BE
IN THE CENTRAL CARIBBEAN BY MIDDAY WEDNESDAY. INTERESTS IN THE
EASTERN/CENTRAL CARIBBEAN SHOULD MONITOR THE PROGRESS OF
CHANTAL.

HISPANIOLA...
SCATTERED SHOWERS/THUNDERSTORMS ARE IMPACTING SOUTHERN HAITI
FROM 18N-20N BETWEEN 71W-75W. A SLOT OF DRIER AIR IS EVIDENT IN
TOTAL PRECIPITABLE WATER IMAGERY AHEAD OF MOISTURE WITH CHANTAL
WHICH MAY PROVIDE A SHORT BREAK IN PRECIPITATION. CHANTAL IS
EXPECTED TO BE NEAR HISPANIOLA BY MIDDAY WEDNESDAY. HEAVY
RAINFALL IS POSSIBLE AND THE PROGRESS OF CHANTAL SHOULD BE
WATCHED CLOSELY.

ATLANTIC OCEAN...
TROPICAL STORM CHANTAL IS IN THE TROPICAL ATLC. SEE SPECIAL
FEATURES ABOVE. BROAD SURFACE RIDGING DOMINATES THE WEST ATLC
AROUND A 1024 MB HIGH NEAR 33N67W. THE RIDGE IS SUPPORTED BY AN
UPPER LEVEL RIDGE TO THE NORTH CENTERED NEAR 36N62W.
HOWEVER...AN UPPER LEVEL LOW TO THE SOUTH OVER THE BAHAMAS NEAR
25N77W IS ENHANCING ACTIVITY NORTH OF A TROPICAL WAVE NEAR 79W.
SCATTERED SHOWERS/THUNDERSTORMS ARE FROM 21N-23N BETWEEN 70W-
74W...AND FROM 26N-29N BETWEEN 71W-76W. ACROSS THE CENTRAL
ATLC...A SURFACE TROUGH...REMNANTS OF A FRONTAL BOUNDARY...ARE
ALONG 31N41W TO 27N49W. ISOLATED SHOWERS ARE WITHIN 30 NM OF THE
AXIS. AN UPPER TROUGH NORTH OF THE AREA SUPPORTS THE SURFACE
TROUGH. SEVERAL UPPER LEVEL ANTI-CYCLONE CENTERS ARE THROUGHOUT
THE CENTRAL AND EASTERN ATLC. ONE IS CENTERED NEAR 28N47W. A
SECOND CENTER IS TO THE SOUTH NEAR 17N42W...EAST OF CHANTAL. THE
THIRD CENTER IS NEAR 19N28W OVER THE EASTERN ATLC. AN UPPER
TROUGH EXTENDS FROM 30N31W TO 24N46W. AT THE SURFACE...BROAD
RIDGING IS PRESENT ANCHORED BY A 1025 MB AZORES HIGH. VERY DRY
AIR IS THROUGHOUT THE EAST ATLC DUE TO THE PRESENCE OF A BROAD
SAHARAN AIR LAYER...WHICH IS KEEPING CONDITIONS FAIR ACROSS MUCH
OF THE AREA.

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

$$
WALTON


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