[Tropical] Tropical Weather Discussion

[EMWIN Server]

AXNT20 KNHC 190553
TWDAT

TROPICAL WEATHER DISCUSSION
NWS TPC/NATIONAL HURRICANE CENTER MIAMI FL
205 AM EDT WED SEP 19 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 0000 UTC SURFACE ANALYSIS AND SATELLITE IMAGERY THROUGH
0515 UTC.

...SPECIAL FEATURE...
A LARGE AREA OF DISTURBED WEATHER OVER THE WESTERN ATLANTIC...
NORTHERN BAHAMAS...AND THE EAST COAST OF FLORIDA IS ASSOCIATED
WITH A 1012 MB SFC LOW LOCATED NEAR 25N79W AT 19/0300 UTC
INTERACTING WITH AN UPPER-LEVEL LOW. THERE ARE NO SIGNS OF
ORGANIZATION AT THIS TIME. HOWEVER...SURFACE PRESSURES ARE
GRADUALLY FALLING AND ENVIRONMENTAL CONDITIONS APPEAR FAVORABLE
FOR A SUBTROPICAL OR A TROPICAL CYCLONE TO FORM OVER THE NEXT
DAY OR TWO...AS THE DISTURBANCE MOVES WESTWARD OVER FLORIDA AND
INTO THE GULF OF MEXICO. REGARDLESS OF DEVELOPMENT...THIS SYSTEM
WILL LIKELY BRING SHOWERS...SQUALLS...AND LOCALLY HEAVY RAINS
OVER PORTION OF FLORIDA DURING THE NEXT DAY OR TWO. MOSAIC
DOPPLER RADAR FROM THE SE US SHOWS SCATTERED TO NUMEROUS SHOWERS
WITH EMBEDDED TSTMS ALONG THE EAST FLORIDA COAST AND ADJACENT
COASTAL WATERS NORTH OF WEST PALM BEACH.

...TROPICAL WAVES...
TROPICAL WAVE IS ALONG 26W/27W S OF 16N MOVING W 10-15 KT. A
BROAD CYCLONIC TURNING IS ALONG THE WAVE AXIS NEAR 11N.
SCATTERED MODERATE CONVECTION IS FROM 8N-12N BETWEEN 25W-31W.

TROPICAL WAVE IS ALONG 51W/52W S OF 21N MOVING W NEAR 15 KT.
SHOWER AND THUNDERSTORM ACTIVITY REMAINS DISORGANIZED IN
ASSOCIATION WITH THIS TROPICAL WAVE. UPPER-LEVEL WINDS ARE
UNFAVORABLE FOR DEVELOPMENT OF THIS SYSTEM. A CLUSTER OF
MODERATE CONVECTION HAS DEVELOPED ON THE NORTHERN END OF THE
WAVE AXIS FROM 17N-20N BETWEEN 46W-49W.

TROPICAL WAVE IS ALONG 82W S OF 20W MOVING W 10-15 KT. SHOWER
ACTIVITY REMAINS LIMITED IN ASSOCIATION WITH THIS WAVE.

...THE ITCZ...
ITCZ AXIS IS CENTERED ALONG 11N16W 8N25W 6N35W 7N50W 7N62W. A
CLUSTER OF MODERATE TO ISOLATED STRONG CONVECTION IS INLAND OVER
W AFRICA MOVING W ALONG THE IMMEDIATE COASTAL WATERS WITHIN 150
NM OF THE ITCZ AXIS. THIS ACTIVITY MAY BE ASSOCIATED WITH A NEW
TROPICAL WAVE. SCATTERED MODERATE CONVECTION IS WITHIN 140 NM
EITHER SIDE OF THE AXIS BETWEEN 30W-35W.

DISCUSSION...

GULF OF MEXICO...
AS WAS PREDICTED BY THE COMPUTER MODELS...A CLOSED UPPER LOW IS
CENTERED ALONG THE W COAST OF FLORIDA NEAR TAMPA COVERING THE
EASTERN GULF AND THE STATE OF FLORIDA. A MID/UPPER LEVEL TROUGH
EXTENDS ACROSS THE EASTERN US TO THIS LOW. NLY WINDS ON THE
WEST SIDE OF THE LOW ARE ADVECTING VERY DRY AIR INTO THE E GULF.
A 1012 MB SFC LOW CURRENTLY LOCATED OVER THE STRAITS OF FLORIDA
IS INTERACTING WITH THIS UPPER LOW. THE SFC LOW IS EXPECTED TO
MOVE W INTO GULF OF MEXICO THIS MORNING. THIS LOW PRES MAY
DEVELOP INTO A SUBTROPICAL OR TROPICAL CYCLONE. FOR MORE DETAILS
SEE SPECIAL FEATURE. AN UPPER RIDGE EXTENDS ACROSS THE W-CENTRAL
GULF FROM THE YUCATAN PENINSULA TO THE COAST NEAR THE
LOUISIANA/TEXAS BORDER. ANOTHER UPPER LOW IS INLAND OVER MEXICO
NEAR 23N99W SPREADING MOISTURE THROUGH SOUTH-CENTRAL MEXICO...
THE BAY OF CAMPECHE AND THE SW GULF. SFC RIDGING DOMINATES THE
SE US AND THE NORTHERN GULF WATERS PRODUCING MODERATE NE TO E
WINDS OF 15 TO 20 KT N OF 26N. AN EARLIER QUIKSCAT PASS
CONFIRMED THESE WINDS...STRONGEST OVER THE NE CORNER OF THE
GULF. A PATCH OF SHOWERS AND TSTMS IS NEAR 26N84W. WIDELY
SCATTERED SHOWERS ARE SEEN OVER THE REMAINDER OF THE GULF.

CARIBBEAN SEA...
A RIDGE/TROUGH/RIDGE PATTERN DOMINATES THE CARIBBEAN SEA. AN
UPPER RIDGE ANCHORED ON A HIGH OVER NICARAGUA COVERS THE NW
CARIBBEAN ENHANCING SHOWER ACTIVITY OVER CENTRAL AMERICA. A WEAK
SURFACE TROUGH IS BENEATH THIS UPPER RIDGE EXTENDING ALONG THE
YUCATAN PENINSULA/NORTHERN GUATEMALA GENERATING SCATTERED
SHOWERS AND TSTMS INLAND. A SECOND UPPER HIGH IS IN THE SE
CARIBBEAN NEAR 12N62W COVERING THE REMAINDER OF THE AREA. IN
BETWEEN... THERE IS AN UPPER TROUGH THAT EXTENDS ACROSS THE
CENTRAL CARIBBEAN FROM HAITI TO E PANAMA. A SURFACE TROUGH
EXTENDS FROM THE REMNANTS OF INGRID IN THE NE CARIBBEAN
GENERATING SCATTERED SHOWERS/ISOLATED THUNDERSTORMS OVER THE
NORTHERN LEEWARD ISLANDS. SOME SHOWER ACTIVITY IS ALONG THE
NORTHERN COAST OF CUBA ASSOCIATED WITH SFC LOW LOCATED OVER THE
STRAITS OF FLORIDA.

ATLANTIC OCEAN...
A LARGE AREA OF DISTURBED WEATHER OVER THE WESTERN ATLANTIC...
NORTHERN BAHAMAS...AND THE EAST COAST OF FLORIDA REMAINS THE
MAIN FEATURE OF INTEREST IN THE ATLANTIC. REFER TO SPECIAL
FEATURE FOR MORE DETAILS. THE UPPER LOW ALONG THE W COAST OF
FLORIDA EXTENDS ACROSS THE FLORIDA PENINSULA AND THE W ATLC TO
75W. AN UPPER HIGH IS TO THE E NEAR 26N71W WITH THE RIDGE AXIS
EXTENDING N TO BEYOND 32N67W. AN UPPER TROUGH ENTERS THE AREA
NEAR 32N52W EXTENDING SW TO 22N66W. THERE ARE TWO UPPER LOWS
EMBEDDED IN THIS TROUGH. ONE IS NEAR 25N63W...THE SECOND ONE IS
NEAR 32N52W. A SURFACE TROUGH RELATED TO THIS UPPER TROUGH
EXTENDS FROM 31N50W TO NEAR 25N60W. LOW TO MID CLOUDS WITH
SCATTERED SHOWERS/ISOLATED THUNDERSTORMS ARE JUST E AND WITHIN
150 NM OF THE SURFACE TROUGH. THE REMNANT CIRCULATION OF INGRID
IS ANALYZED AS A 1012 MB SURFACE LOW LOCATED JUST N OF THE
LEEWARD ISLANDS NEAR 20N63W WITH A SURFACE TROUGH EXTENDING
ALONG 62W/63W S OF 25N INTO THE NE CARIBBEAN. SCATTERED MODERATE
CONVECTION IS JUST E OF THE SURFACE LOW FROM 19N-22N BETWEEN
60W-63W. AN UPPER RIDGE GENERALLY ALONG 15N COVERS THE TROPICAL
ATLC. N OF THE RIDGE UPPER WLY FLOW DOMINATES THE REMAINDER OF
THE FORECAST AREA E OF 40W.

$$
GR



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