[Tropical] Tropical Weather Discussion

[EMWIN Server]

AXNT20 KNHC 181104
TWDAT

TROPICAL WEATHER DISCUSSION
NWS TPC/NATIONAL HURRICANE CENTER MIAMI FL
805 AM EDT FRI JUL 18 2008

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
1015 UTC.

...SPECIAL FEATURES...

TROPICAL STORM BERTHA IS CENTERED NEAR 34.8N 53.7W AT 18/0900
UTC MOVING NORTHEAST AT 15 KT. ESTIMATED MINIMUM CENTRAL
PRESSURE IS 997 MB. MAXIMUM SUSTAINED WIND SPEED IS 50 KT WITH
GUSTS TO 60 KT. PLEASE SEE THE LATEST NHC FORECAST/ADVISORY
UNDER AWIPS/WMO HEADERS MIATCMAT2/WTNT22 KNHC AND THE PUBLIC
ADVISORY UNDER MIATCPAT2/WTNT32 KNHC FOR MORE DETAILS. BERTHA IS
MAINTAINING TROPICAL STORM STRENGTH WITH A WELL-DEFINED CLOUD
PATTERN AND LIMITED OUTFLOW ALOFT. AS BERTHA MOVES OVER COOLER
OCEANIC WATERS IT IS EXPECTED TO BECOME FULLY EMBEDDED WITHIN
THE HIGH LATITUDE WESTERLIES THIS WEEKEND. SCATTERED SHOWERS
WITH POSSIBLE EMBEDDED TSTMS ARE FROM 34N-37N BETWEEN 53W-56W.

TROPICAL WAVE IS ALONG 69W/70W S OF 19N WITH A 1008 MB LOW ALONG
THE WAVE AXIS NEAR 13N MOVING W NEAR 20 KT. SURFACE OBSERVATIONS
ACROSS THE CENTRAL CARIBBEAN AND RADAR DATA OVERNIGHT FROM
CURACAO INDICATE A BROAD LOW EXISTS NORTH OF CURACAO AND ARUBA.
ENVIRONMENTAL CONDITIONS ARE EXPECTED TO GRADUALLY BECOME MORE
FAVORABLE OVER THE NEXT DAY OR SO AS THE SYSTEM MOVES WESTWARD
INTO AN AREA OF BETTER UPPER LEVEL DIFFLUENCE ACROSS THE WRN
CARIBBEAN. HEAVY RAINS AND GUSTY WINDS ARE POSSIBLE OVER
NORTHERN VENEZUELA AND ADJACENT ISLANDS FRI AND THIS WEEKEND.
SCATTERED MODERATE CONVECTION REMAINS FROM 12N-16N BETWEEN
66W-72W SURROUNDING THE LOW. ELSEWHERE...SCATTERED SHOWERS AND
POSSIBLE ISOLATED THUNDERSTORMS COVER THE REMAINDER OF THE AREA
S OF 17N BETWEEN 65W-73W.

TROPICAL WAVE IS ALONG 85W S OF 22N WITH A 1008 MB LOW ALONG THE
WAVE NEAR 14N. THIS SYSTEM HAS SLOWED TO NEAR 10-15 KT GIVEN THE
LARGE EXPANSIVE AREAL COVERAGE OF THE OVERALL CIRCULATION. THE
LOW HAS MOVED INLAND ACROSS NRN NICARAGUA AND IT IS NOT EXPECTED
TO BECOME A TROPICAL DEPRESSION. HOWEVER...SHOWERS AND GUSTY
WINDS ARE EXPECTED TO CONTINUE OVER THE NW CARIBBEAN SEA AND
PORTIONS OF HONDURAS...NICARAGUA...GUATEMALA AND BELIZE. THIS
ACTIVITY COULD CAUSE LIFE-THREATENING FLASH FLOODS AND
MUDSLIDES. SCATTERED SHOWERS/ISOLATED THUNDERSTORMS ARE FROM
11N-19N BETWEEN 80W-90W.

A 1013 MB LOW IS OFF THE COAST OF SOUTHERN GEORGIA NEAR 31N80.5W
WITH A SURFACE TROUGH EXTENDING SW ACROSS CENTRAL FLORIDA.
ENVIRONMENTAL CONDITIONS COULD ALLOW FOR SOME SLOW DEVELOPMENT
OF THIS SYSTEM DURING THE NEXT COUPLE OF DAYS AS THE LOW DRIFTS
TO THE NORTH OR NORTH-NORTHEAST AND REMAINS OVER THE OPEN WATERS
OF THE W ATLC. SCATTERED SHOWERS/THUNDERSTORMS REMAIN IN THE W
ATLC FROM 28N-32N BETWEEN 76W-81W.

...TROPICAL WAVES...

TROPICAL WAVE IS ALONG 47W S OF 19N MOVING W NEAR 15 KT. HIGH
AMPLITUDE INVERTED-V CURVATURE IS OBSERVED ON SATELLITE IMAGERY
WITH NO ASSOCIATED SHOWERS OR DEEP CONVECTION.

...THE ITCZ...
ITCZ AXIS IS CENTERED ALONG 14N16W 4N30W 5N45W 9N50W 9N61W.
SCATTERED MODERATE CONVECTION IS FROM 7N-10N BETWEEN 13W-16W.
SCATTERED MODERATE/ISOLATED STRONG CONVECTION IS WITHIN 90 NM OF
THE ITCZ AXIS BETWEEN 23W-29W. CLUSTERS OF SCATTERED MODERATE
CONVECTION ARE FROM 6N-9N BETWEEN 53W-59W.

...DISCUSSION...

GULF OF MEXICO...
MAIN AREA OF ADVERSE WEATHER IS OFF THE NE FLORIDA PENINSULA
AND INTO THE W ATLC DUE TO THE 1013 MB LOW OFF THE COAST OF
JACKSONVILLE FLORIDA. AN UPPER LOW IS OVER THE NW GULF NEAR
25N97W WITH AN UPPER RIDGE COVERING THE ERN GULF AND RIDGE AXIS
EXTENDING FROM THE FLORIDA PANHANDLE TO THE YUCATAN CHANNEL.
THESE UPPER FEATURES ARE RATHER BENIGN AS A WEAK SURFACE RIDGE
REMAINS IN PLACE ACROSS THE ENTIRE REGION AND IS KEEPING LIGHT
WINDS AND RELATIVELY TRANQUIL WEATHER ACROSS THE GULF.

CARIBBEAN SEA...
THE FOCUS ACROSS THE CARIBBEAN SEA IS TWO FOLD...THE TROPICAL
WAVE ALONG 85W AND THE ERN CARIBBEAN TROPICAL WAVE ALONG 69/70W.
SEE SPECIAL FEATURES ABOVE. THESE TWO SYSTEMS ENCOMPASS MOST OF
THE CARIBBEAN. UPPER LEVEL LOW LOCATED OVER THE SE BAHAMAS
EXTENDS TROUGHING ACROSS ERN CUBA AND JAMAICA. EAST OF THE
TROUGH AXIS WHICH IS ALONG 74W...UPPER DIFFLUENCE IS GENERATING
AN AREA OF SCATTERED SHOWERS ACROSS THE WINDWARD PASSAGE AND WRN
HISPANIOLA. ELSEWHERE...UPPER LEVEL SUBSIDENCE AND DRY AIR IS
ACROSS THE LEEWARD/VIRGIN ISLANDS AND PUERTO RICO.

ATLANTIC OCEAN...
THE MAIN AREA OF CONCENTRATION FOR THE W ATLC IS THE 1013 MB LOW
OFF THE SRN GEORGIA COAST AND TROPICAL STORM BERTHA WHICH
REMAINS NORTH OF THE REGION. SEE SPECIAL FEATURES ABOVE. A SMALL
AND NARROW RIDGE OF HIGH PRESSURE IS LOCATED SW OF T.S. BERTHA
ALONG A LINE 22N55W 24N68W TO THE CENTRAL BAHAMAS. A SURFACE
TROUGH EXTENDS S-SW OF BERTHA AND ENTERS THE DISCUSSION AREA
NEAR 32N53W TO 28N60W. SCATTERED SHOWERS AND A FEW EMBEDDED
TSTMS ARE WITHIN 50 NM ON EITHER SIDE OF THE TROUGH. AN UPPER
HIGH IS LOCATED SE OF BERTHA AND KEEPING MOST OF THE CENTRAL
ATLC DRY WITH FAIR WEATHER. HOWEVER AN UPPER LOW CENTERED NEAR
18N55W E OF THE LESSER ANTILLES EXTENDS TROUGHING N-NE TO NEAR
27N49W. AN AREA OF DIFFLUENCE IS GENERATING POSSIBLE SCATTERED
SHOWERS FROM 20N-25N BETWEEN 46W-50W. A SURFACE RIDGE COVERS THE
ERN ATLC E OF 46W ANCHORED BY 1031 MB HIGH N-NW OF THE AZORES.

$$
HUFFMAN




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