[Tropical] Tropical Weather Discussion

[EMWIN Server]

AXNT20 KNHC 071752
TWDAT

TROPICAL WEATHER DISCUSSION
NWS TPC/NATIONAL HURRICANE CENTER MIAMI FL
205 PM EDT WED OCT 07 2009

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 1200 UTC SURFACE ANALYSIS AND SATELLITE IMAGERY THROUGH
1715 UTC.

...SPECIAL FEATURES...

TROPICAL STORM HENRI IS CENTERED NEAR 18.9N 57.4W AT 07/1500
UTC...OR ABOUT 325 NM E OF THE NRN LEEWARD ISLANDS MOVING WNW AT
13 KT. ESTIMATED MINIMUM CENTRAL PRESSURE IS 1007 MB. MAXIMUM
SUSTAINED WIND SPEED IS 40 KT WITH GUSTS TO 50 KT. NUMEROUS
STRONG CONVECTION IS FROM 17N-20N BETWEEN 54W-56W. SCATTERED
MODERATE CONVECTION IS FROM 16N-21N BETWEEN 52W-57W. SEE LATEST
NHC FORECAST/ADVISORY UNDER AWIPS/WMO HEADERS MIATCMAT5/WTNT25
KNHC FOR MORE DETAILS.

...TROPICAL WAVES...

TROPICAL WAVE IS ALONG 48W S OF 11N MOVING W NEAR 20 KT. A 0900
UTC QUIKSCAT PASS INDICATED LOW-LEVEL CYCLONIC FLOW AROUND THE
WAVE AXIS. THE WAVE ALSO COINCIDES WITH A DEEP LAYER MOISTURE
MAXIMUM OBSERVED IN TOTAL PRECIPITABLE WATER IMAGERY. WIDELY
SCATTERED MODERATE CONVECTION IS FROM 6N-13N BETWEEN 44W-53W.

TROPICAL WAVE IS ALONG 68W S OF 15N MOVING W NEAR 15 KT. VISIBLE
SATELLITE IMAGERY INDICATES BROAD CYCLONIC TURNING OVER THE SE
CARIBBEAN IN THE VICINITY OF THE WAVE...ALONG WITH A DEEP LAYER
MOISTURE MAXIMUM AS INDICATED BY TOTAL PRECIPITABLE WATER
IMAGERY. THE WAVE IS MOVING BENEATH UPPER LEVEL TROUGHING ACROSS
THE ERN CARIBBEAN...WITH SCATTERED MODERATE CONVECTION FROM
12N-15N BETWEEN 65W-70W. THIS CONVECTION IS MORE LIKELY
ASSOCIATED WITH THE UPPER LEVEL TROUGH THAN THE WAVE.

...ITCZ...

THE ITCZ AXIS IS CENTERED ALONG 11N15W 8N20W 7N30W 6N40W 8N46W
7N48W 6N58W. SCATTERED MODERATE/ISOLATED STRONG CONVECTION IS
LOCATED FROM THE COAST OF AFRICA FROM 4N-11N BETWEEN 13W-29W.

...DISCUSSION...

GULF OF MEXICO...
SURFACE HIGH PRESSURE IS CENTERED NEAR THE WEST COAST OF
FLORIDA...WITH A RIDGE STRETCHING WSW ACROSS THE GULF. A COLD
FRONT IS LOCATED 100 NM INLAND OVER THE GULF COAST STATES. DRY
AIR AND SUBSIDENCE COVERS THE BASIN...RESULTING IN FAIR WEATHER.
ANTI-CYCLONIC SURFACE FLOW REMAINS IN PLACE AROUND THE RIDGE...
WITH WINDS BETWEEN 15-20 KT IN THE WESTERN GULF. EXPECT THE
RIDGE TO PERSIST FOR THE NEXT FEW DAYS...AND THE COLD FRONT TO
STALL OUT FROM THE FLORIDA BIG BEND TO SOUTHEAST TEXAS THIS
WEEKEND.

CARIBBEAN SEA...
AN UPPER LEVEL LOW IS OVER THE WESTERN CARIBBEAN...MOVING INLAND
NEAR THE BORDER OF NICARAGUA/HONDURAS. THE UPPER LOW IS
SUPPORTING SCATTERED SHOWERS/ISOLATED THUNDERSTORMS ACROSS THE
WESTERN PORTION OF THE BASIN S OF 19N BETWEEN 76W-87W. AN UPPER
LEVEL TROUGH IS LOCATED OVER THE EASTERN CARIBBEAN WITH AXIS
ALONG 15N FROM 61W-71W...OVER THE WINDWARD ISLANDS AND INTO THE
ATLANTIC. MOIST DIFFLUENT FLOW AROUND THE UPPER TROUGH IS
SUPPORTING A LINE/ZONE OF SCATTERED SHOWERS/ISOLATED
THUNDERSTORMS FROM 14N60W TO 13N71W. A TROPICAL WAVE ALONG 68W
IS ALSO ENHANCING THE CONVECTIVE ACTIVITY. MODERATE TO FRESH
TRADEWINDS ARE ACROSS MUCH OF THE BASIN WITH STRONGER WINDS IN
THE WESTERN AND CENTRAL CARIBBEAN.

ATLANTIC OCEAN...
TROPICAL STORM HENRI REMAINS THE BIGGEST WEATHER MAKER OVER THE
ATLANTIC. SEE SPECIAL FEATURES ABOVE. A DYING COLD FRONT OVER
THE NORTHWEST PORTION OF THE BASIN FROM 31N77W TO NORTHEAST OF
THE DISCUSSION AREA WILL DISSIPATE TONIGHT. AN UPPER LEVEL
TROUGH IS FARTHER EAST OVER THE NORTH CENTRAL PORTION OF THE
BASIN SUPPORTING A COLD FRONT AT THE SURFACE FROM 31N49W TO
NORTH OF THE AREA. SCATTERED SHOWERS/ISOLATED THUNDERSTORMS ARE
WITHIN 250 NM TO THE SOUTHEAST OF THE FRONT. A 1024 MB SURFACE
HIGH IS CENTERED NEAR 25N41W WITH ANOTHER 1023 MB SURFACE HIGH
CENTERED NEAR 30N36W. RIDGING EXISTS ACROSS THE MAJORITY OF THE
ATLANTIC WITH THE EXCEPTION BEING A WEAKNESS IN THE RIDGE TO THE
NORTHEAST OF TROPICAL STORM HENRI. AN UPPER LEVEL LOW CENTERED
NEAR 30N32W IS MOVING THROUGH THE EASTERN PORTION OF THE RIDGE
PRODUCING ISOLATED/SCATTERED SHOWERS.

$$
LEWITSKY/HUFFMAN


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