[Tropical] Tropical Weather Discussion

[EMWIN Server]

AXNT20 KNHC 100547
TWDAT

TROPICAL WEATHER DISCUSSION
NWS TPC/NATIONAL HURRICANE CENTER MIAMI FL
205 AM EDT THU SEP 10 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 0000 UTC SURFACE ANALYSIS AND SATELLITE IMAGERY THROUGH
0515 UTC.

...SPECIAL FEATURES...

HURRICANE FRED IS CENTERED NEAR 15.3N 33.7W AT 10/0300 UTC OR
ABOUT 560 NM W OF THE CAPE VERDE ISLANDS MOVING NW AT 9 KT.
ESTIMATED MINIMUM CENTRAL PRESSURE IS 965 MB. MAXIMUM SUSTAINED
WIND SPEED IS 90 KT WITH GUSTS TO 110 KT. SCATTERED MODERATE/
STRONG CONVECTION IS FROM 14N-18N BETWEEN 31W-35W. WIDELY
SCATTERED MODERATE CONVECTION IS ELSEWHERE FROM 9N-20N BETWEEN
29W-38W. SEE LATEST NHC FORECAST/ADVISORY UNDER AWIPS/WMO
HEADERS MIATCMAT2/WTNT22 KNHC FOR MORE DETAILS.

...TROPICAL WAVES...

TROPICAL WAVE IS ALONG 70W S OF 19N MOVING W NEAR 18 KT. THE
WAVE COINCIDES WITH A DEEP LAYER MOISTURE MAXIMUM OBSERVED IN
THE TOTAL PRECIPITABLE WATER IMAGERY AND CONTINUES TO MOVE
BENEATH UPPER LEVEL SWLY FLOW E OF AN UPPER LEVEL TROUGH ACROSS
THE CENTRAL CARIBBEAN. NO DEEP CONVECTION IS CURRENTLY
ASSOCIATED WITH THE WAVE AS HIGH LEVEL CIRRUS IS NOTED ON
SATELLITE IMAGERY.

TROPICAL WAVE IS ALONG 90W S OF 20N MOVING W NEAR 20 KT. THIS
WAVE REMAINS ILL-DEFINED AND DIFFICULT TO LOCATE DUE TO DRY NLY
WINDS ALOFT ACROSS THE YUCATAN PENINSULA AND PORTIONS OF CENTRAL
AMERICA. NO DEEP CONVECTION IS CURRENTLY ASSOCIATED WITH THE
WAVE.

...ITCZ...

THE ITCZ AXIS IS CENTERED ALONG 11N16W 16N29W 13N38W 6N57W.
ASIDE FROM CONVECTION ASSOCIATED WITH HURRICANE FRED...
SCATTERED MODERATE CONVECTION IS FROM 10N-13N BETWEEN 18W-24W.
ISOLATED MODERATE CONVECTION IS FROM 5N-8N BETWEEN 40W-49W.

...DISCUSSION...

GULF OF MEXICO...
STRONG NWLY UPPER LEVEL FLOW DOMINATES ACROSS THE GULF AS UPPER
LEVEL TROUGHING ACROSS THE W ATLC AND FLORIDA PENINSULA WHILE AN
UPPER LEVEL ANTICYCLONIC CIRCULATION CENTERED OVER THE ERN
PACIFIC EXTENDS UPPER RIDGING ACROSS CENTRAL MEXICO AND THE WRN
GULF. A FAIR AMOUNT OF UPPER LEVEL MOISTURE IN THE FORM OF HIGH
LEVEL CLOUDINESS IS NOTED ON INFRARED SATELLITE IMAGERY ACROSS
THE GULF THIS MORNING. WITH THE LACK OF ANY SIGNIFICANT SURFACE
FEATURES AND A WEAK PRESSURE GRADIENT PRESENT...UPPER DIFFLUENCE
ASSOCIATED WITH THE UPPER LEVEL RIDGING IS GENERATING ISOLATED
SHOWERS AND TSTMS ACROSS THE WRN GULF W OF 93W. MORE WIDESPREAD
CONVECTION IS LOCATED INLAND ACROSS INTERIOR ERN MEXICO. AS OF
0300 UTC...A SURFACE TROUGH EXTENDS FROM NEAR MIAMI FLORIDA
THROUGH KEY WEST TO NEAR CANCUN MEXICO AND REMAINS LOCATED NEAR
THE BASE OF THE AFOREMENTIONED TROUGHING OVER THE W ATLC.
LOW-LEVEL CONVERGENCE ALONG THE SURFACE TROUGH...AS CAPTURED BY
A 2330 UTC SCATTEROMETER PASS...ARE GENERATING SCATTERED SHOWERS
AND TSTMS OVER THE SE GULF AND STRAITS OF FLORIDA S OF 27N E OF
84W.

CARIBBEAN SEA...
A SURFACE TROUGH EXTENDS FROM NEAR KEY WEST FLORIDA OVER THE
YUCATAN CHANNEL TO CANCUN MEXICO. LOW-LEVEL CONVERGENCE NEAR THE
SURFACE TROUGH AND UPPER LEVEL DIFFLUENCE LOCATED OVER CUBA IS
SUPPORTING SCATTERED SHOWERS AND TSTMS OVER THE NW CARIBBEAN
FROM 18N-23N BETWEEN 81W-85W. THE REMAINDER OF THE WRN AND
CENTRAL CARIBBEAN IS EXPERIENCING GENERALLY FAIR WEATHER UNDER
DRY SUBSIDENT AIR DUE TO NLY FLOW ALOFT ON THE ERN PERIPHERY OF
AN UPPER LEVEL RIDGE OVER SRN MEXICO AND A LARGE PORTION OF
CENTRAL AMERICA. UPPER LEVEL TROUGHING IS ACROSS THE CENTRAL
CARIBBEAN BETWEEN 68W-82W AND CONTINUES DRAWING UPPER LEVEL
MOISTURE ON SWLY WINDS FROM NRN SOUTH AMERICA AND PANAMA TO OVER
THE S/CENTRAL CARIBBEAN TO PUERTO RICO. MODERATE TO FRESH TRADE
WINDS ARE ACROSS MUCH OF THE BASIN WITH POSSIBLE PASSING
ISOLATED SHOWERS OVER THE SW CARIBBEAN S OF 14N BETWEEN 75W-82W.

ATLANTIC OCEAN...
A SURFACE TROUGH ENTERS THE DISCUSSION AREA NEAR 32N72W AND
EXTENDS SSW TO NEAR MIAMI FLORIDA. LOW-LEVEL CONVERGENCE NEAR
THE SURFACE TROUGH IS SUPPORTING SCATTERED SHOWERS AND TSTMS
OVER MUCH OF THE SW NORTH ATLC S OF 29N BETWEEN
72W-81W...INCLUDING THE NW AND CENTRAL BAHAMAS AS WELL AS
PORTIONS OF THE FLORIDA STRAITS. THIS ACTIVITY IS ALSO ENHANCED
BY UPPER LEVEL DIFFLUENCE AND MOIST SWLY FLOW ALOFT AROUND AN
UPPER LEVEL TROUGH THAT DIPS SWD FROM THE ERN CONUS OVER THE
FLORIDA PENINSULA AND W ATLC WATERS TO 24N. FARTHER TO THE SE...
AN UPPER LEVEL LOW IS CENTERED NEAR 26N67W AND HAS CONTINUED TO
BE ABSORBED INTO THE MAIN WRN ATLC TROUGH OVER THE PAST 24
HOURS. A SURFACE TROUGH IS ANALYZED TO THE SE OF THE UPPER LOW
FROM 24N62W TO 19N64W AND COUPLED WITH UPPER LEVEL DIFFLUENCE
ASSOCIATED WITH THE UPPER LOW IS GENERATING SCATTERED SHOWERS
AND ISOLATED TSTMS FROM 19N-23N BETWEEN 61W-70W. A 1020 MB
SURFACE HIGH IS CENTERED NEAR 29N59W. A WEAKENING STATIONARY
FRONT ENTERS THE DISCUSSION AREA NEAR 32N43W AND EXTENDS SW TO
26N48W. POSSIBLE ISOLATED SHOWERS ARE WITHIN 60 NM EITHER SIDE
OF THE FRONTAL BOUNDARY. A SURFACE TROUGH EXTENDS FROM 16N45W TO
24N43W. ISOLATED SHOWERS ARE LOCATED WITHIN 60 NM EITHER SIDE OF
THE TROUGH AXIS. THIS SURFACE TROUGH IS SUPPORTED ALOFT BY AN
UPPER LOW CENTERED NEAR 22N47W. ELSEWHERE ACROSS THE TROPICAL
ATLC...HURRICANE FRED REMAINS THE MAIN CONCERN. AN UPPER LEVEL
ANTICYCLONIC FLOW IS OVER THE ERN ATLC S OF 25N E OF 42W AND
CONTINUES TO ENHANCE THE CONVECTION AND OUTFLOW ASSOCIATED WITH
HURRICANE FRED.

$$
HUFFMAN



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