[Tropical] Tropical Weather Discussion

[EMWIN Server]

AXNT20 KNHC 080541
TWDAT

TROPICAL WEATHER DISCUSSION
NWS NATIONAL HURRICANE CENTER MIAMI FL
205 AM EDT MON JUL 08 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 0300 UTC...TROPICAL STORM CHANTAL HAS FORMED IN THE
TROPICAL ATLC. AT 0600 UTC...THE CENTER OF CHANTAL IS NEAR 10.1N
48.5W...OR ABOUT 675 NM ESE OF BARBADOS MOVING W NEAR 23 KT.
ESTIMATED MINIMUM CENTRAL PRESSURE IS 1007 MB. MAXIMUM SUSTAINED
WIND SPEED IS 35 KT WITH GUSTS TO 45 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.
TROPICAL STORM WATCHES AND WARNINGS HAVE BEEN ISSUED FOR
PORTIONS OF THE LESSER ANTILLES. TOTAL RAIN ACCUMULATIONS OF 2-4
INCHES ARE EXPECTED WITH MAXIMUM OF 6 INCHES POSSIBLE. CURRENTLY
SCATTERED MODERATE/STRONG CONVECTION IS FROM 7N-11N BETWEEN 45W-
48W WITH THE STRONGEST CONVECTION NEAR THE STORM CENTER.

...TROPICAL WAVES...
TROPICAL WAVE IS ALONG 11N24W TO 4N24W MOVING WEST AT 10-15 KT.
THE WAVE ALIGNS WITH A LOW-AMPLITUDE 700 MB TROUGH AXIS.
ISOLATED MODERATE CONVECTION IS FROM 5N-9N BETWEEN 26W-29W.

TROPICAL WAVE IS ALONG 25N71W TO 9N77W MOVING WEST NEAR 15 KT.
THE WAVE IS ON THE WEST SIDE OF A SURGE OF DEEP LAYER MOISTURE
PRESENT IN TOTAL PRECIPITABLE WATER IMAGERY. SOME DRIER AIR
APPEARS TO BE PRESENT FROM ABOUT 13N-17N. THE NORTHERN PORTION
OF THE WAVE IS ALSO UNDER THE INFLUENCE OF AN UPPER LEVEL LOW
CENTERED NEAR 24N73W. IT IS HARD TO DETERMINE WHICH FEATURE IS
CONTRIBUTING TO CONVECTION IN THE AREA. REGARDLESS...SCATTERED
MODERATE/ISOLATED STRONG CONVECTION IS FROM 19N-21N BETWEEN 64W-
70W. STRONG CONVECTION IS ALSO INLAND OVER NORTHERN COLOMBIA
NEAR A 1005 MB LOW FROM 6N-10N BETWEEN 73W-77W.

...ITCZ/MONSOON TROUGH...
THE MONSOON TROUGH EXTENDS FROM THE COAST OF GUINEA NEAR 11N15W
TO 8N23W 9N33W. THE ITCZ BEGINS NEAR 9N33W AND CONTINUES ALONG
12N42W WHERE IT BREAKS DUE TO TROPICAL STORM CHANTAL. A SMALL
SECTION OF THE ITCZ CONTINUES WEST OF THE STORM ALONG 8N50W TO
5N53W. SCATTERED MODERATE/ISOLATED STRONG CONVECTION ARE FROM 7N-
11N BETWEEN 14W-20W.

...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. HOWEVER...DEEP LAYER MOISTURE REMAINS THROUGHOUT MUCH OF
THE AREA. CURRENTLY...SCATTERED SHOWERS/THUNDERSTORMS ARE IN THE
NE GULF FROM 26N-30N BETWEEN 83W-85W..AND IN THE WESTERN GULF
FROM 21N-24N BETWEEN 97W-99W. POSSIBLE ISOLATED SHOWERS ARE
ACROSS MUCH OF THE REMAINING PORTION OF THE BASIN EXCEPT THE SE
CORNER WHERE DRIER AIR ALOFT IS PROVIDING FAIRER CONDITIONS.
ELSEWHERE ALOFT...MOIST AIR STREAMS AROUND AN UPPER LEVEL RIDGE
WITH AXIS FROM LOUISIANA NEAR 30N92W TO 22N98W. AT THE
SURFACE...EAST TO SOUTHEAST WINDS OF 10-15 KT SPREAD THROUGHOUT
THE BASIN AROUND THE SURFACE RIDGE. LITTLE CHANGE IS EXPECTED
SYNOPTICALLY WITH SURFACE RIDGING DOMINATING THE AREA...AND
MOIST AIR REMAINING OVER THE NW HALF OF THE BASIN.

CARIBBEAN SEA...
MUCH OF THE CARIBBEAN IS EXPERIENCING FAIR CONDITIONS DESPITE
THE PRESENCE OF A TROPICAL WAVE EXTENDING FROM THE WINDWARD
PASSAGE TO NORTHERN COLOMBIA. A FEW ISOLATED
SHOWERS/THUNDERSTORMS ARE SOUTH OF WESTERN CUBA. SIMILAR
ACTIVITY IS OVER THE FAR SW CARIBBEAN SOUTH OF 11N NEAR THE
WAVE...AND THE MONSOON TROUGH THAT EXTENDS ALONG 8N TO A 1005 MB
SURFACE LOW OVER NORTHERN COLOMBIA. STRONGER CONVECTION IS OVER
NORTHERN COLOMBIA ASSOCIATED WITH THE LOW PRESSURE CENTER AND
THE WAVE. OTHER ACTIVITY ASSOCIATED WITH THE WAVE IS NORTH OF
THE CARIBBEAN AND IS ENHANCED BY AN UPPER LEVEL LOW NEAR 24N74W.
THE ONLY OTHER ACTIVITY IN THE BASIN IS OVER THE LESSER ANTILLES
WHERE SCATTERED SHOWERS ARE MOVING THROUGH EAST OF 62W.
ALOFT...MOSTLY DRY AIR IS PRESENT AROUND AN UPPER LEVEL RIDGE
CENTERED NEAR 13N67W. UPPER LEVEL TROUGHING IS ONLY OVER THE NW
CORNER...BUT IS ACCOMPANIED BY DRY AIR ALOFT. THE WAVE IS
EXPECTED TO CONTINUE MOVING WEST. TROPICAL STORM CHANTAL IS EAST
OF THE LESSER ANTILLES...BUT IS MOVING QUICKLY AND EXPECTED TO
REACH THE ISLANDS BY TUESDAY MORNING. INTERESTS IN THE EASTERN
CARIBBEAN SHOULD MONITOR THE PROGRESS OF CHANTAL.

HISPANIOLA...
HISPANIOLA IS FAIRLY DRY DESPITE SCATTERED SHOWERS/THUNDERSTORMS
IMMEDIATELY NORTH OF THE ISLAND. MOISTURE EAST OF THE TROPICAL
WAVE IN THE WINDWARD PASSAGE STILL LINGERS NEAR THE ISLAND...BUT
IS MAINLY KEEPING TO THE NORTH. TOTAL PRECIPITABLE WATER IMAGERY
INDICATES MORE MOISTURE IS STILL FARTHER EAST AND COULD IMPACT
HISPANIOLA OVER THE NEXT COUPLE OF DAYS. TROPICAL STORM CHANTAL
MAY ALSO IMPACT THE ISLAND BY THE MIDDLE OF THE WEEK.

ATLANTIC OCEAN...
TROPICAL STORM CHANTAL IS IN THE TROPICAL ATLC. SEE SPECIAL
FEATURES ABOVE. BROAD SURFACE RIDGING DOMINATES THE WEST ATLC
AROUND A 1023 MB HIGH NEAR 33N72W. THE RIDGE IS SUPPORTED BY AN
UPPER LEVEL RIDGE TO THE NORTH CENTERED NEAR 37N66W.
HOWEVER...AN UPPER LEVEL LOW TO THE SOUTH OVER THE BAHAMAS NEAR
24N74W IS ENHANCING ACTIVITY NEAR A TROPICAL WAVE NEAR 72W.
SCATTERED SHOWERS/ISOLATED THUNDERSTORMS ARE FROM 19N-25N
BETWEEN 65W-72W. ACROSS THE CENTRAL ATLC...A SURFACE TROUGH IS
ANALYZED ALONG 22N55W TO 13N57W. NO SHOWERS ARE ASSOCIATED WITH
THE TROUGH. A SECOND SURFACE TROUGH...REMNANTS OF A FRONTAL
BOUNDARY ARE ALONG 32N40W 28N47W 26N54W. ISOLATED
SHOWERS/POSSIBLE THUNDERSTORMS ARE FROM 29N-31N BETWEEN 41W-
49W.AN UPPER TROUGH IS ALONG 37W NORTH OF 23N SUPPORTING THE
SURFACE TROUGH. THE REMAINDER OF THE BASIN IS DOMINATED BY BROAD
SURFACE RIDGING AROUND A 1026 MB HIGH NEAR 33N31W. ALOFT...UPPER
RIDGING DOMINATES THE TROPICAL ATLC AND FAR EASTERN ATLC. 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


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