[Tropical] Tropical Weather Discussion

[EMWIN Server]

AXNT20 KNHC 101806
TWDAT

TROPICAL WEATHER DISCUSSION
NWS NATIONAL HURRICANE CENTER MIAMI FL
205 PM EDT TUE SEP 10 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 1200 UTC SURFACE ANALYSIS AND SATELLITE IMAGERY THROUGH
1715 UTC.

...SPECIAL FEATURES...
TROPICAL STORM GABRIELLE IS CENTERED NEAR 30.6N 65.0W AT 10/1500
UTC OR ABOUT 103 NM S OF BERMUDA MOVING N AT 10 KT. ESTIMATED
MINIMUM CENTRAL PRESSURE IS 1008 MB. MAXIMUM SUSTAINED WIND
SPEED IS 35 KT WITH GUSTS TO 45 KT. NUMEROUS MODERATE/ISOLATED
STRONG CONVECTION IS FROM 30N-32N BETWEEN 63W-65W. SCATTERED
MODERATE CONVECTION IS ELSEWHERE FROM 28N-34N BETWEEN 58W-65W.
SEE LATEST NHC INTERMEDIATE PUBLIC ADVISORY UNDER AWIPS/WMO
HEADERS MIATCPAT2/WTNT32 KNHC AND THE FULL FORECAST/ADVISORY
UNDER AWIPS/WMO HEADERS MIATCMAT2/WTNT22 KNHC FOR MORE DETAILS.

TROPICAL STORM HUMBERTO IS CENTERED NEAR 14.6N 27.7W AT 10/1500
UTC OR ABOUT 192 NM W OF THE SOUTHERNMOST CAPE VERDE ISLANDS
MOVING W-NW AT 8 KT. ESTIMATED MINIMUM CENTRAL PRESSURE IS 998
MB. MAXIMUM SUSTAINED WIND SPEED IS 55 KT WITH GUSTS TO 65 KT.
NUMEROUS MODERATE CONVECTION IS FROM 10N-16N BETWEEN 25W-32W.
SEE LATEST NHC INTERMEDIATE PUBLIC ADVISORY UNDER AWIPS/WMO
HEADERS MIATCPAT4/WTNT34 KNHC AND THE FULL FORECAST/ADVISORY
UNDER AWIPS/WMO HEADERS MIATCMAT4/WTNT24 KNHC FOR MORE DETAILS.

...TROPICAL WAVES...
A TROPICAL WAVE IS IN THE CENTRAL ATLC WITH AXIS EXTENDING FROM
21N48W TO A 1014 MB LOW NEAR 17N45W AND CONTINUES MOVING W NEAR
10-15 KT. TOTAL PRECIPITABLE WATER IMAGERY SHOW MOSTLY A
MODERATE MOIST ENVIRONMNENT NW OF THE LOW PRESSURE CENTER
WHEREAS VERY DRY AIR WRAPS UP THE REMAINING IMMEDIATE
ENVIRONMENT OF THE SYSTEM. SCATTERED MODERATE CONVECTION IS
OBSERVED FROM 18N-20N BETWEEN 49W-52W COLLOCATED WITH AN A SMALL
AREA OF HIGH MOISTURE.

A TROPICAL WAVE IS ANALYZED FROM THE GULF OF MEXICO NEAR 22N95W
TO S MEXICO NEAR 16N95W INTO THE E PACIFIC REGION NEAR 10N94W
AND IS MOVING NEAR 5 KT. TOTAL PRECIPITABLE WATER IMAGERY SHOW A
MOISTURE MAXIMUM OVER THE WESTERN BAY OF CAMPECHE AS WELL AS IN
THE REGION OF THE E PACIFIC WHERE THE WAVE IS EMBEDDED. OVER THE
PORTION OF THE WAVE IN THE GULF...SCATTERED MODERATE CONVECTION
LIES E-NE OF THE WAVE AXIS FROM 20N-26N BETWEEN 90W-95W BEING
ENHANCED BY UPPER LEVEL DIFFLUENCE. NUMEROUS MODERATE/ISOLATED
STRONG CONVECTION ASSOCIATED WITH THE MONSOON TROUGH IS OVER THE
E PACIFIC FROM 07N-14N BETWEEN 91W-100W.

...THE ITCZ/THE MONSOON TROUGH...
THE MONSOON TROUGH EXTENDS ACROSS AFRICA TO THE COAST OF
MAURITANIA. THE ITCZ BEGINS SW OF TROPICAL STORM HUMBERTO NEAR
07N39W AND CONTINUES ALONG 08N52W TO SOUTH AMERICA NEAR 09N60W.
THE MONSOON TROUGH OVER THE E ATLC HAS BEEN DISRUPTED BY
TROPICAL STORM HUMBERTO. NUMEROUS MODERATE CONVECTION IS FROM
14N-23N E OF 23W. SCATTERED MODERATE CONVECTION IS FROM 05N-07N
BETWEEN 17W-22W AS WELL AS FROM 04N-07N BETWEEN 30W-39W.

...DISCUSSION...

GULF OF MEXICO...
SURFACE RIDGING DOMINATES THE EASTERN GULF WHERE LOW TO MIDDLE
LEVEL DRY AIR SUPPORTS FAIR WEATHER THIS AFTERNOON. OVER THE
WESTERN GULF...A TROPICAL WAVE IS ANALYZED FROM 22N95W TO S
MEXICO NEAR 16N95W INTO THE E PACIFIC REGION NEAR 10N94W. TOTAL
PRECIPITABLE WATER IMAGERY SHOW A MOISTURE MAXIMUM OVER THE
WESTERN BAY OF CAMPECHE WHERE THE NORTHERN PORTION OF THE WAVE
IS EMBEDDED. SCATTERED MODERATE CONVECTION LIES E-NE OF THE WAVE
AXIS FROM 20N-26N BETWEEN 90W-95W BEING ENHANCED BY UPPER LEVEL
DIFFLUENCE. WEST OF 96W...A LINE OF RAINSHOWERS ASSOCIATED WITH
A SURFACE TROUGH LINGERS FROM 21N-28N. SURFACE RIDGING WILL
PREVAIL OVER THE N-NE GULF THROUGH SAT. A TROUGH OF LOW PRESSURE
IS EXPECTED TO DEVELOP OVER THE SW GULF BY WED AND LINGER
THROUGH SAT WITH THE POSSIBILITY OF IT DEVELOPING INTO A MORE
IDENTIFIABLE LOW PRESSURE SYSTEM.

CARIBBEAN SEA...
A MIDDLE-LEVEL LOW...SLOWLY TRANSITIONING INTO AN INVERTED
TROUGH IS BEING REFLECTED AT THE SURFACE AS A TROUGH THAT
EXTENDS FROM 21N87W IN THE YUCATAN PENINSULA TO ADJACENT WATERS
OF BELIZE NEAR 16N87W. THIS MIDDLE-LEVEL LOW/INVERTED TROUGH
ALONG WITH UPPER-LEVEL DIVERGENCE CONTINUES TO SUPPORT SCATTERED
MODERATE/ISOLATED STRONG CONVECTION OVER THE WESTERN CARIBBEAN
FROM 15N-21N W OF 81W. FARTHER EAST...MIDDLE-LEVEL DIFFLUENCE
AND UPPER-LEVEL DIVERGENCE COLLOCATED WITHIN A REGION OF HIGH
MOISTURE SUPPORT NUMEROUS MODERATE/ISOLATED STRONG CONVECTION
AND TSTMS FROM 16N-21N BETWEEN 75W-81W...INCLUDING CUBA AND
JAMAICA. AN UPPER-LEVEL LOW COVERS THE REMAINING BASIN E OF 74W.
HOWEVER...LOW AND MIDDLE LEVEL DRY AIR IS SUPPORTING
SUBSIDENCE...THUS FAIR WEATHER FOR MOST OF THIS REGION. TOTAL
PRECIPITABLE WATER IMAGERY SHOW A SLIGHLY MOIST ENVIRONMENT E OF
64W S OF 17N WHERE ISOLATED SHOWERS ARE OBSERVED...INCLUDING THE
LESSER ANTILLES. MODERATE TO FRESH TRADE WINDS WILL CONTINUE
ACROSS THE CENTRAL AND E CARIBBEAN THROUGH THU WHILE GENTLE TO
MODERATE TRADE WINDS CONTINUE ACROSS THE W CARIBBEAN.

HISPANIOLA...
CLEAR SKIES DOMINATE ACROSS THE ISLAND THIS AFTERNOON BEING
SUPPORTED BY DRY AIR IN THE LOWER-LEVELS AND LIGHT TRADE WINDS.
ISOLATED SHOWERS ARE POSSIBLE THIS AFTERNOON DUE TO SURFACE
HEATING BUT MOSTLY FAIR WEATHER WILL DOMINATE TODAY. SIMILAR
CONVECTION IS TO THE WINDWARD PASSAGE BEING SUPPORTED BY A HIGH
MOIST ENVIRONMENT AND MIDDLE-LEVEL DIFFLUENCE. A DRY AIRMASS IS
EXPECTED TO MOVE ACROSS THE ISLAND SINCE TUE AFTERNOON PROVIDING
FAIR WEATHER UNTIL WED NIGHT.

ATLANTIC OCEAN...
THE PRIMARY CONCERNS FOR THE ATLC BASIN THIS MORNING ARE
TROPICAL STORM HUMBERTO IN THE E ATLC AND TROPICAL STORM
GABRIELLE IN THE W ATLC. SEE SPECIAL FEATURES ABOVE. ALSO SEE
THE TROPICAL WAVES SECTION FOR DISCUSSION OF A WAVE IN THE
CENTRAL ATLC. AN UPPER-LEVEL TROUGH COVERS W ATLC WITH A LOW
CENTERED NEAR 28N77W AND EXTENDING A TROUGH AXIS ACROSS THE
FLORIDA STRAITS TO CUBA. THIS UPPER-LEVEL LOW IS REFLECTED IN
THE MIDDLE LEVELS AND SUPPORTS SCATTERED SHOWERS/ISOLATED
THUNDERSTORMS N OF 25N W OF 70W. S OF THE MIDDLE TO UPPER LEVEL
LOW IS THE WEAK RIDGE THAT COVERS THE W CARIBBEAN WHICH IS
CAUSING UPPER-LEVEL DIFFLUENCE...THUS SUPPORTING SCATTERED
MODERATE CONVECTION AND TSTMS OVER THE BAHAMAS. AN UPPER LOW IS
IN THE E/CENTRAL ATLC NEAR 28N42W GENERATING SCATTERED
SHOWERS/ISOLATED THUNDERSTORMS FROM 26N-32N BETWEEN 40W-45W. THE
REMAINDER OF THE ATLC IS DOMINATED BY A SURFACE RIDGE ANCHORED
BY A 1034 MB HIGH N OF THE AZORES. TROPICAL STORM GABRIELLE WILL
MOVE N OF THE AREA TONIGHT. A WEAK PRESSURE PATTERN WILL PREVAIL
ELSEWHERE ACROSS THE AREA.

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

$$
NR


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