[Tropical] Tropical Weather Discussion

[EMWIN Server]

AXNT20 KNHC 121753
TWDAT

TROPICAL WEATHER DISCUSSION
NWS NATIONAL HURRICANE CENTER MIAMI FL
205 PM EDT MON SEP 12 2011

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 MARIA IS CENTERED NEAR 20.7N 67.3W AT 12/1500 UTC
OR ABOUT 150 NM N-NW OF SAN JUAN PUERTO RICO AND ABOUT 710 NM S
OF BERMUDA MOVING W AT 2 KT. ESTIMATED MINIMUM CENTRAL PRESSURE
IS 1006 MB. MAXIMUM SUSTAINED WIND SPEED IS 45 KT WITH GUSTS TO
55 KT. SCATTERED MODERATE AND ISOLATED STRONG CONVECTION IS FROM
19N-22N BETWEEN 62W-66W. ISOLATED MODERATE CONVECTIVE IS FARTHER
SE FROM THE CENTER OF MARIA OCCURRING OVER THE NE CARIBBEAN SEA
FROM 10N-18N BETWEEN 62W-68W...IMPACTING THE US/UK VIRGIN
ISLANDS AND PORTIONS OF THE NORTHERN LEEWARD ISLANDS. MARIA IS
EXPECTED TO PRODUCE TOTAL RAIN ACCUMULATIONS OF 2-4 INCHES WITH
ISOLATED MAXIMUM AMOUNTS OF 6 INCHES OVER THE VIRGIN ISLANDS...
PUERTO RICO...AND PORTIONS OF THE NORTHERN LEEWARD ISLANDS
THROUGH TUE. SEE THE LATEST FORECAST/ADVISORY UNDER AWIPS/WMO
HEADERS MIATCMAT4/WTNT24 KNHC FOR MORE DETAILS.

...TROPICAL WAVES...

TROPICAL WAVE IS ANALYZED FROM 12N53W TO 22N51W MOVING W AT
15-20 KT. THE WAVE IS EMBEDDED WITHIN AN AREA OF MAXIMUM DEEP
LAYER MOISTURE AS DEPICTED ON TOTAL PRECIPITABLE WATER IMAGERY.
METEOSAT-9 VISIBLE SATELLITE IMAGERY ALSO SHOWS CYCLONIC TURNING
OF THE LOW-LEVEL CLOUD FIELD IN THE VICINITY OF THE WAVE AXIS.
FURTHERMORE...AN EARLIER MORNING ASCAT PASS 12/1326 UTC DEPICTED
THOSE SURFACE CYCLONIC WINDS WITH SOME 20 KT NE WINDS NEAR
20N52W. NO SIGNIFICANT DEEP CONVECTION IS ASSOCIATED WITH THE
WAVE.

TROPICAL WAVE IS ANALYZED FROM 13N84W TO 17N86W TO 22N87W MOVING
W-NW AT 5-10 KT. LOW TO MID-LEVEL CYCLONIC TURNING OF THE CLOUD
FIELD IS NOTED ALONG THE WAVE AXIS AS IT MOVES BENEATH THE
SOUTHERN PERIPHERY OF AN UPPER LEVEL ANTICYCLONIC CIRCULATION
CENTERED NEAR 19N87W. SCATTERED MODERATE AND ISOLATED STRONG
CONVECTION IS OCCURRING FROM 15N-19N BETWEEN 83W-89W.

...ITCZ/MONSOON TROUGH...

THE MONSOON TROUGH EXTENDS FROM THE AFRICAN COAST NEAR 12N16W
ALONG 07N28W TO 08N37W. ISOLATED MODERATE CONVECTION IS FROM
04N-13N BETWEEN 12W-37W.

...DISCUSSION...

GULF OF MEXICO...
A BROAD UPPER LEVEL TROUGH IS SWINGING ACROSS THE SOUTHEASTERN
CONUS AND DIPS SOUTHWARD INTO THE GULF WATERS REMAINING N OF
23N. THIS TROUGH IS SUPPORTING A STATIONARY FRONT EXTENDING FROM
NE FLORIDA NEAR JACKSONVILLE SW TO NEAR 28N84W. WHILE THE FRONT
REMAINS PRECIPITATION FREE...PRE-FRONTAL LOW-LEVEL MOISTURE AND
CONVERGENCE FOCUSED ALONG A SURFACE TROUGH EXTENDING FROM LAKE
OKEECHOBEE SW TO 25N83W IS GENERATING ISOLATED SHOWERS AND TSTMS
WITHIN 60 NM EITHER SIDE OF THE SURFACE TROUGH. WATER VAPOR
IMAGERY INDICATES THAT VERY DRY AIR IS ASSOCIATED WITH THE UPPER
LEVEL TROUGH AND THAT VERY STRONG SUBSIDENCE CONTINUES TO
PROGRESS ACROSS THE NORTHERN GULF WATERS THIS AFTERNOON. THIS
OVERALL DRYING IS SUPPORTIVE OF A SURFACE RIDGE EXTENDING FROM A
1021 MB HIGH CENTERED OVER SW ALABAMA SOUTHWESTWARD TO EAST-
CENTRAL MEXICO NEAR 21N97W. MOSTLY NE WINDS TO 15 KT ARE
EXPECTED TO PERSIST THROUGH LATE WEDNESDAY ACROSS MUCH OF THE
GULF AS THE RIDGE REMAINS FAIRLY STATIONARY.

CARIBBEAN SEA...
TROPICAL STORM MARIA CONTINUES TO IMPACT THE EASTERN CARIBBEAN
WITH SCATTERED SHOWERS AND ISOLATED TSTMS W OF 68W TO THE LESSER
ANTILLES NEAR 60W. THIS AREA OF PRECIPITATION ASSOCIATED WITH
MARIA IS ENHANCED DUE TO AN UPPER LEVEL RIDGE AXIS EXTENDING
FROM CUBA ACROSS HISPANIOLA TO NEAR 17N63W...AND IS FORECAST TO
TRACK NW AS MARIA MOVES MORE NORTH OF THE BASIN. THE CENTRAL
CARIBBEAN REMAINS FAIRLY QUIET THIS AFTERNOON CONVECTIVELY AS
WELL AS AT THE SURFACE AS WINDS ARE EXPECTED TO REMAIN EASTERLY
IN THE RANGE OF 10 TO 15 KT. FARTHER WEST...A TROPICAL WAVE OVER
THE NW CARIBBEAN IS BEGINNING TO MOVE INLAND OVER PORTIONS OF
CENTRAL AMERICA. CURRENTLY NUMEROUS SHOWERS AND SCATTERED STRONG
TSTMS ARE OCCURRING FROM 15N-19N BETWEEN 83W-89W...INCLUDING THE
GULF OF HONDURAS. AS THIS TROPICAL WAVE SLOWLY MOVES W-NW...
HEAVY RAINFALL IS EXPECTED TO CONTINUE ACROSS INTERIOR PORTIONS
OF BELIZE...HONDURAS...THE YUCATAN PENINSULA...AND GUATEMALA
WITH THE POSSIBILITY OF FLASH FLOODING AND MUDSLIDES.

ATLANTIC OCEAN...
AN UPPER LEVEL TROUGH IS SWEEPING ACROSS THE SE CONUS AND
SUPPORTS A STATIONARY FRONT EXTENDING FROM 32N81W TO 30N81W THEN
SW INTO THE NE GULF OF MEXICO. A PRE-FRONTAL SURFACE TROUGH IS
ANALYZED SE OF THE FRONT FROM 29N80W TO LAKE OKEECHOBEE. LOW-
LEVEL MOISTURE CONVERGENCE ALONG WITH LIFT PROVIDED BY THE UPPER
LEVEL TROUGHING IS GENERATING SCATTERED SHOWERS AND TSTMS WITHIN
120 NM EITHER SIDE OF A LINE FROM 32N76W TO 24N80W OVER THE SW
NORTH ATLC WATERS. FARTHER TO THE SE...TROPICAL STORM MARIA IS
FORECAST TO CONTINUE TRACKING W-NW AND BEGIN A MORE NORTHWARD
TRACK OVER THE NEXT FEW DAYS. AN UPPER LEVEL LOW CENTERED NEAR
26N65W IS ADVECTING MIDDLE TO UPPER LEVEL MOISTURE OVER A LARGE
PORTION OF THE W ATLC WITH WIDELY SCATTERED SHOWERS OCCURRING
FROM 22N-29N BETWEEN 57W-65W. OTHERWISE THE REMAINDER OF THE
CENTRAL AND EASTERN ATLC IS UNDER THE INFLUENCE OF A SURFACE
RIDGE ANCHORED BY A 1026 MB HIGH CENTERED NEAR 29N39W AND A 1025
MB HIGH CENTERED NEAR 31N54W. INFRINGING ON THE EASTERN-MOST
HIGH IS A COLD FRONT ANALYZED FROM 32N37W TO 32N43W. ISOLATED
SHOWERS ARE OCCURRING WITHIN 75 NM EITHER SIDE OF THE FRONT
BETWEEN 36W-44W.

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

$$
HUFFMAN




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