[Tropical] Tropical Weather Discussion

[EMWIN Server]

AXNT20 KNHC 150503
TWDAT

TROPICAL WEATHER DISCUSSION
NWS TPC/NATIONAL HURRICANE CENTER MIAMI FL
205 AM EDT FRI SEP 15 2006

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

BASED ON 0600 UTC SURFACE ANALYSIS AND SATELLITE IMAGERY THROUGH
0345 UTC.

...SPECIAL FEATURES...
HURRICANE GORDON IS CENTERED NEAR 30.6N 54.3W AT 15/0300 UTC
MOVING NORTHEAST AT 8 KT. ESTIMATED MINIMUM CENTRAL PRESSURE IS
960 MB. MAXIMUM SUSTAINED WIND SPEED IS 100 KT WITH GUSTS TO 120
KT. SEE THE LATEST NHC FORECAST/ADVISORY UNDER AWIPS/WMO HEADERS
MIATCMAT2/WTNT22 KNHC FOR MORE DETAILS. DESPITE WARMING CLOUD
TOPS GORDON STILL HAS A SMALL VERY DISTINCT EYE WITH UNIFORM
CONVECTION SURROUNDING THE EYE. SCATTERED MODERATE/ISOLATED
STRONG CONVECTION IS WITHIN 60 NM FROM THE CENTER IN ALL
QUADRANTS. SCATTERED MODERATE CONVECTION IS FROM 28N-33N BETWEEN
50W-54W.

TROPICAL STORM HELENE IS CENTERED NEAR 14.5N 38.9W AT 15/0300
MOVING WEST-NORTHWEST AT 13 KT. 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 MIATCMAT3/WTNT23 KNHC FOR MORE DETAILS. HELENE
HAS HAD A HARD TIME MAINTAINING DEEP CONVECTION DURING THE DAY
THU AND THIS PATTERN IS EXPECTED TO CONTINUE OVER THE NEXT DAY
OR SO. SCATTERED MODERATE TO SCATTERED STRONG CONVECTION COVERS
AN AREA FROM 12N-18N BETWEEN 38W-42W.

...TROPICAL WAVES...
TROPICAL WAVE IS ALONG 59W S OF 15N MOVING W 10-15 KT. WEAK WAVE
SIGNATURE AS THE WAVE APPROACHES THE LESSER ANTILLES. WAVE IS
BENEATH THE W EDGE OF AN UPPER RIDGE AND A LARGE AREA OF VERY
DRY AIR...THUS NO ASSOCIATED DEEP CONVECTION.

TROPICAL WAVE IS ALONG 69W/70W S OF 19N MOVING W 15 KT.
WELL-DEFINED LOW LEVEL INVERTED-V SATELLITE SIGNATURE IS
OBSERVED OVER THE E CARIBBEAN. SCATTERED SHOWERS/ISOLATED
THUNDERSTORMS ARE WITHIN 120 NM OF LINE 13N63W-18N69W.

TROPICAL WAVE IS ALONG 81W S OF 18N MOVING W 15 KT. WEAK LOW
LEVEL INVERTED-V SATELLITE SIGNATURE IS OBSERVED OVER THE W
CARIBBEAN. WAVE IS EMBEDDED WITHIN DRY AIR THUS NO ASSOCIATED
CONVECTION.

...THE ITCZ...
ITCZ AXIS IS CENTERED ALONG 13N15W 15N29W 12N40W 7N49W THEN INTO
THE CARIBBEAN ALONG 11N65W ACROSS THE N PORTION OF SOUTH AMERICA
AND PANAMA INTO THE E PACIFIC REGION NEAR 9N84W. SCATTERED
STRONG CONVECTION IS WITHIN 90/120 NM OF THE AXIS FROM 17W-22W.
SCATTERED MODERATE/STRONG CONVECTION IS WITHIN 150/180 NM S OF
THE AXIS FROM 30W-34W. IN THE CARIBBEAN...SCATTERED
MODERATE/ISOLATED STRONG CONVECTION IS S OF 13N TO INLAND OVER
COLOMBIA FROM 71W-75W.

...DISCUSSION...

GULF OF MEXICO...
BROAD DEEP LAYERED TROUGH COVERS THE E US...THE W ATLC AND THE N
GULF COAST ANCHORED BY AN UPPER LOW MOVING INTO NEW ENGLAND.
ASSOCIATED FRONTAL BOUNDARY EXTENDS INTO THE GULF FROM THE W
ATLC ACROSS THE FLORIDA PENINSULA JUST S OF TAMPA WHERE IT
BECOMING A SURFACE TROUGH ACROSS THE GULF TO THE CENTRAL TEXAS
COAST. WIDELY ISOLATED SHOWERS ARE OVER THE N GULF WITHIN 90/120
NM OF THE FRONT/TROUGH. UPPER RIDGE EXTENDS ACROSS THE REMAINDER
OF THE GULF ANCHORED BY AN UPPER HIGH ASSOCIATED WITH A TROPICAL
STORM OFF THE W COAST OF MEXICO ENTERING THE GULF NEAR TAMPICO
MEXICO TO S FLORIDA JUST N OF THE FLORIDA KEYS THEN INTO THE W
ATLC. THIS IS GENERATING SCATTERED SHOWERS/ISOLATED
THUNDERSTORMS FROM 20N-23N W OF 94W TO INLAND OVER MEXICO.

CARIBBEAN SEA...
W CARIBBEAN IS DOMINATED BY NE UPPER FLOW FROM THE UPPER RIDGE
THAT EXTENDS ACROSS THE GULF OF MEXICO INTO THE W ATLC. THIS IS
PROVIDING DRY AIR ACROSS THE AREA INCLUDING THE TROPICAL WAVE
ALONG 81W. NARROWING UPPER TROUGH EXTENDS FROM HAITI SW TO COSTA
RICA/NICARAGUA BORDER. REMAINDER OF THE CARIBBEAN IS DOMINATED
BY SW TO S UPPER FLOW FROM AN UPPER RIDGE ANCHORED IN THE
TROPICAL/CENTRAL ATLC. THIS RIDGE IS DRAWING ABUNDANT TROPICAL
MOISTURE ACROSS THE S CARIBBEAN AND ESPECIALLY ENHANCING
CONVECTION ASSOCIATED WITH THE ITCZ AXIS OVER COLOMBIA.
SCATTERED SHOWERS/ISOLATED THUNDERSTORMS ARE OVER THE THE N
CARIBBEAN FROM THE N LEEWARD ISLANDS TO OVER CUBA.

ATLANTIC OCEAN...
BROAD DEEP LAYERED TROUGH THAT COVERS THE E US AND THE N GULF
EXTENDS INTO THE W ATLC IS ANCHORED BY AN UPPER LOW MOVING INTO
NEW ENGLAND. THE ASSOCIATED FRONTAL BOUNDARY EXTENDS INTO THE W
ATLC FROM A 1010 MB LOW ALONG THE NORTH/SOUTH CAROLINA COAST
THROUGH 32N77W INTO THE GULF NEAR DAYTONA BEACH FLORIDA GIVING
THE AREA SCATTERED SHOWERS/ISOLATED THUNDERSTORMS E OF THE FRONT
AND NW OF A LINE FROM SE FLORIDA NEAR MIAMI TO BEYOND 32N73W.
UPPER RIDGE AXIS EXTENDS FROM THE GULF OF MEXICO INTO THE W ATLC
ACROSS THE FLORIDA KEYS NE TO NEAR 32N68W. NARROW UPPER TROUGH
EXTENDS ACROSS THE W ATLC JUST TO THE E OF THE UPPER RIDGE
THROUGH 32N63W TO 26N68W CONNECTING TO THE UPPER TROUGH IN THE
CARIBBEAN THAT EXTENDS ACROSS HAITI. THIS GENERATING SCATTERED
SHOWERS/ISOLATED THUNDERSTORMS WITHIN 90/120 NM OF LINE FROM THE
CENTRAL BAHAMAS NEAR 23N75W TO ALONG 27N70W TO BEYOND 32N68W.
BROAD UPPER RIDGE COVERS THE W/CENTRAL AND TROPICAL ATLC
ANCHORED NEAR 21N57W COVERING THE AREA S OF 27N FROM 47W-67W.
TROPICAL MOISTURE IS BEING DRAWN NE OF THE CARIBBEAN AND WITH
SUFFICIENT DIFFLUENCE TO GENERATE AN AREA OF SCATTERED
SHOWERS/ISOLATED THUNDERSTORMS FROM 16N-23N BETWEEN 61W-68W.
GORDON IS N OF THIS UPPER RIDGE. NARROWING UPPER TROUGH EXTENDS
INTO THE E/CENTRAL ATLC NEAR 32N38W S TO 23N43W. HOWEVER...DUE
TO THE DRY AIR IN PLACE NO SHOWER ACTIVITY IS EVIDENT. AN UPPER
RIDGE COVERS THE REMAINDER OF THE E ATLC E OF 37W ANCHORED NEAR
30N26W EXTENDING E TO OVER THE CANARY ISLANDS. AN UPPER HIGH
ASSOCIATED WITH TROPICAL STORM HELENE COVERS THE SE TROPICAL
ATLC WITH A SMALL UPPER LOW JUST TO THE E CENTERED NE OF THE
CAPE VERDE ISLANDS NEAR 20N24W. THE SUBTROPICAL RIDGE IS
BEGINNING TO SPREAD W OVER THE ATLC IN SPITE OF THE PRESENCE OF
HURRICANE GORDON WITH A 1026 MB HIGH OVER THE S MOST ISLANDS OF
THE AZORES. THE LAST VISIBLE SATELLITE IMAGES OF THU SHOWS A
LARGE AREA OF AFRICA DUST FROM THE ITCZ TO 26N BETWEEN 40W-60W
WITH HELENE JUST TO THE E AND YET ANOTHER AREA OF AFRICAN DUST
MOVING OFF AFRICA FROM 13N-22N E OF THE CAPE VERDE ISLANDS.

$$
WALLACE


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