[Tropical] Tropical Weather Discussion

[EMWIN Server]

AXNT20 KNHC 171049
TWDAT

TROPICAL WEATHER DISCUSSION
NWS TPC/NATIONAL HURRICANE CENTER MIAMI FL
805 AM EDT MON SEP 17 2007

TROPICAL WEATHER DISCUSSION FOR NORTH AMERICA...CENTRAL
AMERICA...THE GULF OF MEXICO...THE CARIBBEAN SEA...NORTHERN
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 0600 UTC SURFACE ANALYSIS AND SATELLITE IMAGERY THROUGH
1015 UTC.

...SPECIAL FEATURE...

SATELLITE IMAGERY EARLY THIS MORNING INDICATES THAT TROPICAL
DEPRESSION INGRID IS DISSIPATING EAST OF THE NORTHERN LEEWARD
ISLANDS. AT 17/0900 UTC INGRID IS CENTERED NEAR 17.7N 60.0W OR
ABOUT 100 NM EAST-NORTHEAST OF ANTIGUA MOVING WEST AT 8 KT.
MAXIMUM SUSTAINED WIND SPEED IS 25 KT WITH GUSTS TO 35 KT.
ESTIMATED MINIMUM CENTRAL PRESSURE IS 1010 MB. INGRID CONTINUES
TO LACK ORGANIZED DEEP CONVECTION...AND NO LONGER QUALIFIES AS A
TROPICAL CYCLONE. THE CIRCULATION HAS LITTLE SIGNATURE IN THE
LOW CLOUD LINES AND ITS CENTER SEEMS TO NO LONGER BE WELL
DEFINED. CONSEQUENTLY...THE LAST ADVISORY WAS ISSUED BY THE NHC
AT THIS TIME. THE REMNANTS OF INGRID ARE EXPECTED TO MOVE SLOWLY
TO THE WEST-NORTHWEST OVER THE NEXT DAY OR SO.

...TROPICAL WAVES...

THIS MORNING...THERE IS ONLY ONE TROPICAL WAVE BETWEEN AFRICA
AND THE LESSER ANTILLES. THE WAVE IS TILTED FROM 19N41W TO
6N43W. A LARGE BUT DISORGANIZED AREA OF SHOWERS AND TSTMS IS
ASSOCIATED WITH THIS FEATURE. SATELLITE IMAGERY SHOWS A BROAD
CYCLONIC TURNING NEAR 12N43W. 850 MB MODEL GUIDANCE SUGGESTS
STRONG VORTICITY MAXIMUM IN THIS AREA. IN ADDITION...THE TOTAL
PRECIPITABLE WATER PRODUCT DEPICTS VERY CLEAR THE BULGE OF
MOISTURE ASSOCIATED WITH THIS TROPICAL WAVE. DEVELOPMENT OF THIS
SYSTEM IS EXPECTED TO BE SLOW TO OCCUR AS IT CONTINUES TO MOVE
WESTWARD. CLUSTERS OF MODERATE CONVECTION ARE WITHIN 160-220 NM
EITHER SIDE OF THE AXIS BETWEEN 40W-46W.

TROPICAL WAVE IS ALONG 74W/75W S OF 20N MOVING W 10-15 KT.
CLOUDINESS AND A FEW SHOWERS EXTEND ACROSS THE CENTRAL CARIBBEAN
SEA NORTHWARD TO HISPANIOLA...IN ASSOCIATION WITH THIS WAVE AND
AN UPPER-LEVEL LOW. UPPER-LEVEL WINDS ARE CURRENTLY NOT
FAVORABLE FOR DEVELOPMENT...BUT THEY COULD BECOME A LITTLE MORE
FAVORABLE FOR SLOW DEVELOPMENT OVER THE WESTERN CARIBBEAN OR
EASTERN GULF OF MEXICO IN A COUPLE OF DAYS AS THE SYSTEM MOVES
WESTWARD AT 10 TO 15 MPH.

...THE ITCZ...
ITCZ AXIS IS CENTERED ALONG 11N16W 8N25W 13N41W 11N45W 8N60W. IN
ADDITION TO CONVECTION ASSOCIATED WITH THE TROPICAL WAVE...
SCATTERED MODERATE CONVECTION IS WITHIN 100 NM N OF AXIS BETWEEN
47W-52W. SIMILAR CONVECTION IS WITHIN 200 NM S AXIS E OF 25W. A
CLUSTER OF MODERATE CONVECTION IS JUST MOVING OFF THE AFRICAN
COAST NEAR 10N/11N. THIS ACTIVITY IS LIKELY ASSOCIATED WITH A
NEW TROPICAL WAVE. A QUIKSCAT PASS FROM AROUND 0700 UTC DEPICTED
A BROAD CYCLONIC CIRCULATION BETWEEN 8N-16N. THE VERTICAL
SOUNDING FROM DAKAR IS SHOWING THE PASSAGE OF WAVE EARLY THIS
MORNING. THIS TROPICAL WAVE WILL PROBABLY BE ADDED ON THE 12Z
SURFACE MAP.

DISCUSSION...

GULF OF MEXICO...
AN ELONGATED UPPER LOW IS OVER THE SW GULF/ W BAY OF CAMPECHE
NEAR 20N96W COVERING MOST OF THE WESTERN HALF OF THE GULF. AN
UPPER HIGH IS IN THE SE GULF NEAR 23N85W. DIFFLUENCE BETWEEN
THESE TWO UPPER FEATURES IS ENHANCING SOME SHOWER/TSTM ACTIVITY
OVER THE YUCATAN PENINSULA AND THE BAY OF CAMPECHE. A DEEP
LAYERED UPPER TROUGH IS OVER THE E US INTO THE NE GULF. THE
ASSOCIATED FRONTAL BOUNDARY ENTERS THE W ATLC NEAR 31N74W WHERE
IT BECOMES NEAR STATIONARY THEN CONTINUES ACROSS NORTH-CENTRAL
FLORIDA AND THE CENTRAL GULF TO THE LOWER TEXAS COAST. LIGHTNING
DATA REVEALS TSTM ACTIVITY ALONG THE FRONT...PARTICULARLY JUST E
OF THE FLORIDA PENINSULA...N OF DAYTONA BEACH AND OVER THE NW
CORNER OF THE GULF. DRY AIR IS INVADING THE NORTHERN GULF WATERS
BEHIND THE FRONT. A SFC TROUGH REMAINS OVER THE SE GULF AND
EXTENDS FROM FORT MYERS WESTERN FLORIDA THROUGH WESTERN CUBA
INTO THE CARIBBEAN SEA. THE TROUGH COUPLED WITH A DIFFLUENT
PATTERN ALOFT IS GENERATING SCATTERED SHOWERS AND TSTMS OVER THE
SE GULF. THE FRONT IS EXPECTED TO BECOME DIFFUSE TODAY AND
DISSIPATE TUE.

CARIBBEAN SEA...
THE UPPER HIGH IN THE SE GULF OF MEXICO COVERS WEST-CENTRAL
CUBA...THE NW CARIBBEAN AND NORTHERN CENTRAL AMERICA. ANOTHER
RIDGE ANCHORED ON A HIGH  OVER NE VENEZUELA DOMINATES THE
EASTERN CARIBBEAN. IN BETWEEN...THERE IS AN UPPER TROUGH THAT
EXTENDS FROM AN UPPER LOW OVER THE WINDWARD PASSAGE TO NEAR
12N82W. ABUNDANT MID/UPPER LEVEL MOISTURE IS BEING ADVECTED EAST
OF THE LOW/TROUGH ACROSS THE EAST-CENTRAL CARIBBEAN INTO THE W
ATLC THROUGH PUERTO RICO AND HISPANIOLA. DIFFLUENCE BETWEEN THIS
UPPER FEATURES IS HELPING TO GENERATE A FEW SHOWERS AND TSTMS
MAINLY OVER THE ISLANDS OF HISPANIOLA...CUBA...AND JAMAICA AS
WELL AS OVER THE SE BAHAMAS. LIGHT TO MODERATE TRADE WINDS ARE
BLOWING ACROSS THE BASIN. THE UPPER LOW IS FORECAST TO MOVE
TOWARD THE SE BAHAMAS/NORTHERN HISPANIOLA WITH THE TRAILING
UPPER TROUGH. THIS WEATHER PATTERN WILL CONTINUE TO ENHANCE
CONVECTION OVER THE GREATER ANTILLES DURING THE NEXT FEW DAYS
MAINLY DURING THE AFTERNOON AND EVENING HOURS.

ATLANTIC OCEAN...
THE UPPER TROUGH THAT COVERS THE E US AND THE NE GULF OF MEXICO
EXTENDS INTO THE W ATLC N OF 27N W OF 72W WITH AN ASSOCIATED
FRONTAL SYSTEM ENTERING THE REGION NEAR 31N74W ACROSS THE
FLORIDA PENINSULA AND THE GULF OF MEXICO AS NEAR STATIONARY
FRONT. A 100 NM WIDE BAND OF SCATTERED SHOWERS AND TSTMS IS
RELATED TO THE FRONT. AN UPPER RIDGE EXTENDS FROM THE SE GULF
INTO THE STATE OF FLORIDA AND THE WESTERN ATLC W OF 70W. AN
UPPER LOW IS NEAR 27N61W COVERING THE REMAINDER OF THE W ATLC
INTO CENTRAL ATLC. THIS LOW IS GENERATING CLUSTERS OF MODERATE
TO ISOLATED STRONG CONVECTION FROM 23N-29N BETWEEN 52W-60W. A
SFC TROUGH IS ANALYZED ALONG 62W/63W N OF 23N ON THE 06 Z MAP.
ANOTHER UPPER LOW IS SITUATED NEAR 32N35W. A SURFACE TROUGH IS
ASSOCIATED WITH THIS FEATURE EXTENDING FROM A WEAK 1018 MB LOW
NEAR 32N36W THROUGH 29N36W TO 25N43W WITH SCATTERED SHOWERS
WITHIN 180 NM EAST OF THE SFC LOW/TROUGH. BROAD UPPER RIDGE
DOMINATES MOST OF THE TROPICAL ATLC EXTENDING ALONG 16N FROM W
AFRICA TO JUST SE OF INGRID NEAR 52W. STRONG WLY UPPER WINDS ARE
SEEN OVER THE ATLC N OF 20N E OF 60W.

$$
GR



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