[Tropical] Tropical Weather Discussion

[EMWIN Server]

AXNT20 KNHC 190600
TWDAT

TROPICAL WEATHER DISCUSSION
NWS NATIONAL HURRICANE CENTER MIAMI FL
205 AM EDT SUN AUG 19 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
0545 UTC.

...SPECIAL FEATURES...

HURRICANE GORDON IS LOCATED NEAR 34.6N 32.7W AT 19/0600...OR
ABOUT 395 MI...635 KM WSW OF THE AZORES...MOVING E AT 19 KT.
ESTIMATED MINIMUM CENTRAL PRESSURE IS 965 MB. MAXIMUM SUSTAINED
WIND SPEED IS 90 KT WITH GUSTS TO 110 KT. SATELLITE IMAGERY
SHOWS A WELL DEFINED EYE. SCATTERED MODERATE TO ISOLATED STRONG
CONVECTION IS FROM 32N-37N BETWEEN 30W-35W. GORDON IS EXPECTED
TO PRODUCE TOTAL RAINFALL AMOUNTS OF 3 TO 6 INCHES OVER THE
AZORES.. SEE LATEST NHC INTERMEDIATE PUBLIC ADVISORY UNDER
AWIPS/WMO HEADERS MIATCPAT3/WTNT33 AND THE FULL FORECAST/
ADVISORY UNDER AWIPS/WMO HEADERS MIATCMAT3/WTNT23 KNHC FOR MORE
DETAILS.

AN ACTIVE TROPICAL WAVE IS LOCATED IN THE ERN/CENTRAL TROPICAL
ATLC ALONG 32W...WITH AN ASSOCIATED 1008 MB LOW NEAR 14N32W
EMBEDDED WITHIN THE MONSOONAL GYRE. THIS SYSTEM IS MOVING
WESTWARD AROUND 20 KT. SCATTERED SHOWERS AND THUNDERSTORMS ARE
FROM 10N-18N BETWEEN 30W-37W...WITHIN THE BROAD CONVECTIVE
REGION ASSOCIATED TO THE MONSOON TROUGH. ENVIRONMENTAL
CONDITIONS APPEAR CONDUCIVE FOR A TROPICAL DEPRESSION TO FORM
DURING THE NEXT DAY OR TWO...AND THIS SYSTEM HAS A HIGH CHANCE
OF BECOMING A TROPICAL CYCLONE DURING THE NEXT 48 HOURS AS IT
MOVES WESTWARD AT ABOUT 17 KT. GLOBAL MODELS HAS A WWD
TRAJECTORY TOWARDS THE CARIBBEAN. INTERESTS ACROSS THE E AND NE
CARIBBEAN SHOULD MONITOR THE PROGRESS OF THIS SYSTEM.

...TROPICAL WAVES...

TROPICAL WAVE MOVES ACROSS THE CENTRAL TROPICAL ATLC WITH AXIS
EXTENDING FROM 18N43W TO A WEAK 1010 MB LOW NEAR 10N45W MOVING W
AT 15-20 KT. THE WAVE REMAINS EMBEDDED WITHIN A BROAD AREA OF
ENHANCED DEEP LAYER MOISTURE AS NOTED ON THE TOTAL PRECIPITABLE
WATER IMAGERY. CONVECTION AROUND THE WAVE AXIS IS LIMITED DUE TO
A LARGE DRY AIRMASS ASSOCIATED WITH THE SAHARAN AIR LAYER. ANY
SHOWER ACTIVITY IS LIKELY ASSOCIATED TO THE BROAD MONSOONAL GYRE
DISCUSSED BELOW.

TROPICAL WAVE MOVES ACROSS THE CENTRAL CARIBBEAN WITH AXIS
EXTENDING FROM THE ERN TIP OF CUBA NEAR 20N74W TO BARANOA IN NRN
COLOMBIA NEAR 10N75W MOVING W AT 15-20 KT. THE CIRCULATION
AROUND THE AXIS HAS BROADENED COMPARED TO YESTERDAY...AND THE
OVERALL CONVECTIVE ACTIVITY HAS DECREASED ACCORDINGLY. ONLY A
CLUSTER OF SCATTERED SHOWERS AND THUNDERSTORMS IS NOTED OVER THE
NRN EXTENSION OF THE WAVE AXIS MOVING ACROSS HAITI AND THE
WINDWARD PASSAGE N OF 18N...WHERE LOW LEVEL CONVERGENCE IS
MAXIMIZED COINCIDING WITH A WEAK UPPER LEVEL LOW PROVIDING
FURTHER LIFTING.

...ITCZ/MONSOON TROUGH...

THE MONSOON TROUGH EXTENDS FROM THE AFRICAN COAST OF GUINEA
BISSAU NEAR 12N17W ALONG 16N25W TO THE SPECIAL FEATURE 1008 LOW
PRESSURE SYSTEM NEAR 14N32W TO A WEAKER 1010 MB LOW NEAR 10N45W
TO 7N49W. THE ITCZ AXIS BEGINS FORM THIS POINT TO THE COAST OF
FRENCH GUIANA NEAR 5N53W. A BROAD AREA CONTAINING CLUSTERS OF
SCATTERED MODERATE CONVECTION COVERS FROM 6N-16N BETWEEN
30W-50W...AND FROM 6N-19N E OF 25W.

...DISCUSSION...

GULF OF MEXICO...
THE BASE OF A BROAD UPPER LEVEL TROUGH...MOVING ACROSS THE
CENTRAL AND ERN CONUS...SWINGS ACROSS THE NRN GULF OF MEXICO
PUSHING MULTIPLE SHORTWAVES ABOUT EVERY 6 HOURS. THIS IS
BRINGING SCATTERED SHOWERS AND THUNDERSTORMS OVER THE AREA N OF
25N E OF 95W. WHILE THE UPPER LEVEL TROUGH CONTINUES TO SLOWLY
MOVE ENE ...THE FLOW AROUND THIS FEATURE WILL CONTINUE TO BRING
SEVERAL MORE WAVES OF ENERGY OVER THE NEXT 24 HOURS OVER THE NRN
AND NE BASIN. THUS EXPECT MORE SCATTERED CONVECTION IN THESE
REGIONS DURING THE FORECAST PERIOD. THE BROAD CYCLONIC WIND
FIELD RELATED TO FORMER TROPICAL STORM HELENE CONTINUES TO
GENERATE SCATTERED SHOWERS AND THUNDERSTORMS OVER THE WRN BAY OF
CAMPECHE AND COASTAL WATERS OF TAMPICO S OF 25N W OF 93W. WINDS
WILL REMAIN GENTLE TO MODERATE IN THIS REGION DURING THE NEXT 24
HOURS. LIGHT TO GENTLE SE SURFACE FLOW IS ACROSS THE REMAINDER
OF THE GULF UNDER STABLE CONDITIONS.

CARIBBEAN SEA...
INFRA-RED SATELLITE IMAGERY SHOWS A MID LEVEL MESO-CYCLONE OVER
THE SW CARIBBEAN CENTERED NEAR 12N81W. THIS COORDINATE DOES NOT
REPRESENT A SURFACE CIRCULATION...BUT RATHER A CENTER POSITION
FOR THE MID LEVEL FEATURE. SCATTERED SHOWERS AND ISOLATED
THUNDERSTORMS ARE WITHIN 160 NM FROM THE CENTER AT ALL
QUADRANTS. TO THE E OF THIS FEATURE...A TROPICAL WAVE IS
ANALYZED FROM THE ERN TIP OF CUBA TO THE COAST OF COLOMBIA NEAR
BARANOA. THE CIRCULATION AROUND THE AXIS HAS BROADENED COMPARED
TO YESTERDAY...AND THE OVERALL CONVECTIVE ACTIVITY HAS DECREASED
ACCORDINGLY. ONLY A CLUSTER OF SCATTERED SHOWERS AND
THUNDERSTORMS IS NOTED OVER THE NRN EXTENSION OF THE WAVE AXIS
MOVING ACROSS THE WINDWARD PASSAGE...WHERE LOW LEVEL CONVERGENCE
IS MAXIMIZED COINCIDING WITH A WEAK UPPER LEVEL LOW PROVIDING
FURTHER LIFTING. THE REMAINDER OF THE CARIBBEAN IS DOMINATED BY
DRY AIR AND SUBSIDENCE ALOFT NOTED ON WATER VAPOR IMAGERY.

ATLANTIC OCEAN...
WATER VAPOR CONTINUES TO SHOW A BROAD LONGWAVE UPPER TROUGH
SLOWLY MOVING OFF THE ERN CONUS SEABOARD GENERATING WIDELY
SCATTERED SHOWERS AND THUNDERSTORMS ACROSS THE WRN ATLC
DISCUSSION AREA N OF 25N BETWEEN 63W-80W. AN UPPER LEVEL LOW IS
TO THE E OF THIS CONVECTIVE AREA CENTERED NEAR 24N65W WITHOUT
ANY SIGNIFICANT IMPACTS. OTHERWISE...BROAD SURFACE RIDGING
DOMINATES THE REMAINDER OF THE CENTRAL AND EASTERN ATLC...
GUARDED BY A 1021 MB HIGH CENTERED NEAR 27N57W...AND A 1019 MB
HIGH AROUND 34N25W. THE FAIR WEATHER PRODUCED BY THESE SURFACE
FEATURES IS FURTHER ENHANCED ALOFT BY THE SAHARAN AIR LAYER AND
ASSOCIATED DUST ACROSS MOST OF THE DISCUSSION AREA E OF 65W. THE
HIGHEST CONCENTRATION OF SAHARAN DUST IS NOTED OVER THE FAR ERN
ATLC N OF 17N E OF 34W.

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

$$

GARCIA




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