[Tropical] Tropical Weather Discussion

[EMWIN Server]

AXNT20 KNHC 071043
TWDAT

TROPICAL WEATHER DISCUSSION
NWS TPC/NATIONAL HURRICANE CENTER MIAMI FL
805 AM EDT WED OCT 07 2009

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...METEOROLOGICAL ANALYSIS...WEATHER
OBSERVATIONS...AND RADAR.

BASED ON 0600 UTC SURFACE ANALYSIS AND SATELLITE IMAGERY
THROUGH 1000 UTC.

...SPECIAL FEATURE...

TROPICAL STORM HENRI IS CENTERED NEAR 18.1N 56.1W AT 07/0900
UTC...OR ABOUT 400 NM E OF THE NRN LEEWARD ISLANDS. HENRI IS
MOVING W NEAR 11 KT. ESTIMATED MINIMUM CENTRAL PRESSURE IS
1005 MB. MAXIMUM SUSTAINED WIND SPEEDS HAVE INCREASED TO 45 KT
WITH GUSTS TO 55 KT. LITTLE CHANGE IN INTENSITY IS EXPECTED
TODAY WITH WEAKENING FORECAST TO BEGIN TONIGHT. PLEASE READ THE
NHC FORECAST/ADVISORY UNDER AWIPS/WMO HEADERS MIATCMAT5/ WTNT25
KNHC AND THE PUBLIC ADVISORY UNDER MIATCPAT5/WTNT35 KNHC FOR
MORE DETAILS. SWLY SHEAR IS KEEPING CONVECTION TO THE E OF THE
CENTER. NUMEROUS STRONG CONVECTION IS FROM 17N-21N BETWEEN
52W-56W. SCATTERED MODERATE CONVECTION IS FROM 14N-17N BETWEEN
55W-57W.

...TROPICAL WAVES...

TROPICAL WAVE IS ALONG 45W S OF 10N MOVING W NEAR 15 KT.
SATELLITE IMAGERY INDICATES LOW-LEVEL CYCLONIC FLOW AROUND THE
WAVE AXIS. THE WAVE ALSO COINCIDES WITH A LOW AMPLITUDE DEEP
LAYER MOISTURE MAXIMUM OBSERVED IN TOTAL PRECIPITABLE WATER
IMAGERY. SCATTERED STRONG CONVECTION IS FROM 6N-12N BETWEEN
43W-48W. SCATTERED MODERATE/ISOLATED STRONG CONVECTION IS FROM
6N-11N BETWEEN 48W-52W.

TROPICAL WAVE IS ALONG 66W S OF 14N MOVING W NEAR 12 KT. THE
WAVE LIES WITHIN A LOW-AMPLITUDE...BUT BROAD...DEEP LAYER
MOISTURE MAXIMUM OBSERVED IN TOTAL PRECIPITABLE WATER IMAGERY.
SCATTERED STRONG CONVECTION IS OVER VENEZUELA FROM 7N-8N BETWEEN
66W-70W. AN UPPER LEVEL TROUGH OVER THE ERN CARIBBEAN IS
SHEARING A  LINE OF SCATTERED MODERATE/STRONG CONVECTION NEAR
THE WAVE AXIS FROM 13N70W TO 15N59W. THIS ACTIVITY IS MOST
LIKELY ASSOCIATED MORE WITH THE UPPER TROUGH THAN THE WAVE.

TROPICAL WAVE IS ALONG 95W S OF 18N MOVING W NEAR 15-20 KT. THE
MAIN PORTION OF THE WAVE LIES IN THE E PACIFIC BASIN.
HOWEVER...SCATTERED MODERATE/ISOLATED STRONG CONVECTION IS
AFFECTING THE SW GULF OF MEXICO S OF 20N BETWEEN 94W-96W.

...THE ITCZ...

THE ITCZ AXIS IS CENTERED ALONG 10N15W 6N26W 7N24W 5N32W 8N42W
5N55W. SCATTERED MODERATE/STRONG CONVECTION IS OFF THE COAST OF
AFRICA FROM 6N-11N BETWEEN 11W-17W. SCATTERED MODERATE/ISOLATED
STRONG CONVECTION IS WITHIN 100 NM N OF THE AXIS AND 150 NM S OF
THE AXIS BETWEEN ALONG THE AXIS BETWEEN 20W-27W.

...DISCUSSION...

THE GULF OF MEXICO...
WEAK SURFACE RIDGE IS ACROSS THE BASIN WITH GENERALLY FAIR
WEATHER THROUGHOUT. AN UPPER LEVEL RIDGE CENTERED OVER CENTRAL
MEXICO NEAR 24N101W ALONG WITH DRY AIR AND SUBSIDENCE COVERS THE
AREA SUPPORTING THE FAIR WEATHER. A FEW SHOWERS/THUNDERSTORMS
ARE IN THE FAR SW GULF IN ASSOCIATION WITH A TROPICAL WAVE ALONG
95W. SEE ABOVE. ANTI-CYCLONIC FLOW IS AROUND THE SURFACE RIDGE
WITH WINDS UP TO 20 KT IN THE WRN GULF. EXPECT THE RIDGE TO
PERSIST FOR THE NEXT FEW DAYS.

THE CARIBBEAN SEA...
AN UPPER LEVEL LOW IS OVER THE WRN CARIBBEAN CENTERED OFF THE
COAST OF NICARAGUA NEAR 15N83W. THE UPPER LOW IS SUPPORTING
ISOLATED SHOWERS/THUNDERSTORMS ACROSS THE WRN BASIN S OF 19N
BETWEEN 75W-84W. ANOTHER UPPER LEVEL TROUGH IS LOCATED OVER THE
ERN BASIN WITH AXIS FROM 14N71W ACROSS THE WINDWARD ISLANDS INTO
THE ATLC. MOIST SWLY AND DIFFLUENT FLOW AROUND THE UPPER TROUGH
IS SUPPORTING A LINE OF SCATTERED SHOWERS/THUNDERSTORMS FROM
13N70W TO 15N59W. A TROPICAL WAVE ALONG 66W MAY ALSO BE
ENHANCING SOME OF THIS SHOWER ACTIVITY. MODERATE TO FRESH
TRADEWINDS ARE ACROSS MUCH OF THE BASIN WITH STRONGER WINDS IN
THE SW AND ERN CARIBBEAN. EXPECT THE TROPICAL WAVE ALONG 66W TO
CONTINUE TO MOVE WWD.

THE ATLANTIC OCEAN...
TROPICAL STORM HENRI REMAINS THE BIGGEST WEATHER MAKER OVER THE
ATLC. SEE SPECIAL FEATURES ABOVE. A COLD FRONT CLIPS THE NW
PORTION OF THE BASIN FROM 32N75W TO 31N79W CONTINUING AS A
STATIONARY FRONT TO 32N85W. NO SHOWERS ARE CURRENTLY ASSOCIATED
WITH THE FRONT. AN UPPER LEVEL RIDGE COVERS THE WRN ATLC W OF
70W EXTENDING FROM THE GULF OF MEXICO. AN UPPER LEVEL TROUGH IS
TO THE E BETWEEN 45W-70W SUPPORTING A COLD FRONT EXTENDING
THROUGH THE N CENTRAL ATLC AND BRUSHES THE AREA NEAR 31N54W.
CLOUDINESS AND POSSIBLE ISOLATED SHOWERS ARE WITHIN 250 NM SE OF
THE FRONT. THE REMAINDER OF THE ATLC IS DOMINATED BY A BROAD
SURFACE RIDGE ANCHORED BY SEVERAL SURFACE HIGHS. A 1020 MB HIGH
IS CENTERED NEAR 26N66W TO THE NW OF T.S. HENRI. A 1022 MB HIGH
IS CENTERED NEAR 31N60W TO THE W OF THE COLD FRONT BRUSHING THE
CENTRAL ATLC. A PAIR OF 1022 MB HIGHS ARE CENTERED NEAR 25N40W
AND 31N37W TO THE NE OF HENRI...AND E OF THE COLD FRONT IN THE
CENTRAL ATLC. A WEAK SURFACE TROUGH EXTENDS FROM ANOTHER COLD
FRONT N OF THE DISCUSSION AREA FROM 31N17W TO 27N30W. NO SHOWERS
ARE CURRENTLY ASSOCIATED WITH THE TROUGH. IN THE UPPER
LEVELS...AN UPPER LEVEL TROUGH EXTENDS FROM 29N36W TO 44N13W
SUPPORTING THE SURFACE TROUGH IN THE ERN BASIN. AN UPPER LEVEL
RIDGE COVERS THE BASIN S OF 26N E OF THE LESSER ANTILLES
CENTERED NEAR 13N33W.

$$
WALTON





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