[Tropical] Tropical Weather Discussion

[EMWIN Server]

AXNT20 KNHC 100000
TWDAT

TROPICAL WEATHER DISCUSSION
NWS TPC/NATIONAL HURRICANE CENTER MIAMI FL
805 PM EDT WED MAY 09 2007

TROPICAL WEATHER DISCUSSION FOR NORTH AMERICA...CENTRAL
AMERICA...THE GULF OF MEXICO...THE CARIBBEAN SEA...NORTHEASTERN
SECTIONS OF SOUTH AMERICA...AND THE 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 1800 UTC SURFACE ANALYSIS AND SATELLITE IMAGERY THROUGH
2315 UTC.

...SPECIAL FEATURE...

SUBTROPICAL STORM ANDREA IS CENTERED NEAR 30.5N 79.5W AT 10/0000
UTC OR 110 MILES SE OF SAVANNAH GEORGIA. ANDREA HAS BEEN
MEANDERING DURING THE PAST FEW HOURS. ESTIMATED MINIMUM CENTRAL
PRESSURE IS 1003 MB. MAXIMUM SUSTAINED WIND SPEED IS 40 KT WITH
GUSTS TO 50 KT. SEE THE LATEST NHC FORECAST/ADVISORY UNDER
AWIPS/WMO HEADERS MIATCMAT1/ WTNT21 KNHC FOR MORE DETAILS.
CONVECTION ASSOCIATED WITH THE RATHER LARGE SLOPPY CIRCULATION
OF ANDREA HAS GENERALLY BEEN ON THE DECLINE FOR MUCH OF THE
DAY...ESPECIALLY OVER THE NW QUADRANT. MOSAIC DOPPLER RADAR FROM
THE SOUTHEAST SHOWS NARROW BROKEN BANDS OF SHOWERS AND
ISOLATED TSTMS ONSHORE AND OVER THE COASTAL WATERS.
HOWEVER...OVER THE PAST FEW HOURS AN IMPROVED WIDER BAND OF
CONVECTION HAS TAKEN SHAPE IN THE ERN SEMICIRCLE. THE SYSTEM IS
LOCATED IN WEAK STEERING AND HAS BEEN SLOWLY DRIFTING THROUGHOUT
THE DAY.

...ITCZ...

ITCZ AXIS IS CENTERED ALONG 10N13W 7N22W 3N36W 1N51W. SCATTERED
MODERATE CONVECTION IS WITHIN 60 NM EITHER SIDE OF THE AXIS
BETWEEN 22W-29W. SIMILAR ACTIVITY LIES FROM THE EQ-2N BETWEEN
30W-39W.

...DISCUSSION...

GULF OF MEXICO...
DEEP LAYER NLY FLOW ON THE W SIDE OF ANDREA'S LARGE CIRCULATION
IS ENHANCING SUBSIDENCE ABOVE THE ERN HALF OF THE GULF PROVIDING
WIDESPREAD FAIR WEATHER. THE SMOKE PLUMES ORIGINATING FROM FIRES
IN FLORIDA AND S GEORGIA HAVE NOW SPREAD BOTH TOWARD THE BAY OF
CAMPECHE AND INTO THE WRN ATLC STEERED BY THE DIVERGENT
LOW-LEVEL FLOW BETWEEN ANDREA AND WEAK HIGH PRES TO THE W.
VISIBILITIES ARE MUCH IMPROVED ACROSS THE ERN GULF WATERS N OF
24N. HOWEVER...OBS FROM SE FLORIDA STILL SHOWED VISIBILITIES
REDUCED TO THE 3-5 SM RANGE THIS AFTERNOON...BUT IT SHOULD
IMPROVE THERE SHORTLY. THE WEAK HIGH PRES MENTIONED IS ANALYZED
AT 1018 MB ABOUT 120 NM S OF THE LOUISIANA COAST NEAR 28N92W.
THIS SYSTEM IS PRODUCING LIGHT NE/ELY WINDS W OF 89W AIDING IN
THE TRANQUIL CONDITIONS. FAIRLY LIGHT WINDS AND MOSTLY FAIR
WEATHER IS EXPECTED TO CONTINUE THROUGH FRI AS WEAK HIGH PRES
REMAINS STATIONARY IN THE MID-GULF.

CARIBBEAN SEA...
THE CONTINUED WEAK PRES PATTERN IN THE WRN CARIB IS ALLOWING NE
WINDS TO REMAIN VERY LIGHT...GENERALLY 10 KT OR LESS. THE TRADES
INCREASE TO MORE TYPICAL VALUES IN THE CENTRAL AND ERN
CARIB...15-20 KT...AS SFC RIDGING FROM THE N AND NE HAS BUILT
INTO THE REGION. IN THE UPPER LEVELS...A DEEP TROUGH EXTENDS SWD
FROM THE SUBTROPICAL STORM ACROSS ERN CUBA TO NEAR 14N75W.
ABUNDANT SUBSIDENCE LIES ABOVE AND TO THE W OF THIS AXIS
SUPPRESSING ANY DEEP CLOUD FORMATION. PRONOUNCED UPPER
DIFFLUENCE TO THE E OF THE AXIS IS GENERATING A SWATH OF
MOISTURE BETWEEN 67W-73W. DOPPLER RADAR FROM SAN JUAN PUERTO
RICO SHOWS SCATTERED SHOWERS AND TSTMS IN ITS FAR NW RANGE WHICH
MATCHES UP WITH SATELLITE IMAGERY...SO SCATTERED SHOWERS AND
ISOLATED TSTMS ARE POSSIBLE IN THE AREA OUTLINED.

ATLANTIC...
SUBTROPICAL STORM ANDREA IS THE AREA OF FOCUS THIS EVENING...FOR
DETAILS REFER TO THE SPECIAL FEATURE SECTION ABOVE. AN UPPER
DIFFLUENT ZONE TO THE E OF ANDREA...BETWEEN THE STORM'S EMBEDDED
TROUGH AND RIDGING TO THE E...IS GENERATING A SWATH OF SCATTERED
SHOWERS AND ISOLATED TSTMS BETWEEN 65W-71W. A FEW SHIP
OBSERVATIONS IN THE REGION INDICATE THAT THERE COULD BE A SFC
TROUGH IN THIS AREA OF WEATHER. THIS MAY BE ADDED/BROUGHT BACK
TO THE 00 Z SFC ANALYSIS IF THE DATA CONTINUES TO SUPPORT IT.
FARTHER E...THE UPPER PATTERN FOLDS INTO A VERY BROAD TROUGH.
EMBEDDED IN THIS TROUGH IS A WEAK 1016 MB LOW LOCATED NEAR
34N39W WITH A SFC TROUGH STRETCHING SW TO NEAR 26N52W. THE LAST
FEW VIS SHOTS BEFORE DARKNESS INDICATE THAT THERE COULD BE
ANOTHER WEAK LOW ON THE TROUGH AXIS NEAR 28N. REGARDLESS...THIS
SYSTEM IS WEAK ONLY PRODUCING ISOLATED SHOWERS WITHIN 90 NM OF
THE SFC BOUNDARY. MODERATE TO STRONG SFC HIGH PRES IS IN CONTROL
BOTH TO THE E AND W OF THE LOW PRES TROUGH WITH ONE 1028 MB HIGH
CENTERED IN THE CENTRAL ATLC NEAR 37N55W AND THE OTHER ANALYZED
1024 MB ABOUT 210 NM W OF PORTUGAL NEAR 38N13W. A FAIRLY DENSE
SURGE OF SAHARAN DUST HAS PUSHED INTO THE ATLC WITH THE LEADING
EDGE REACHING 25W. THINNER PATCHES OF DUST HAVE SPREAD FURTHER W
INTO THE CENTRAL ATLC. THIS VERY DRY AIR HAS CLEARED MOST OF THE
LOW TO MID LEVEL CLOUDS IN THE ERN-MOST ATLC.

$$
CANGIALOSI




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