[Tropical] Tropical Weather Discussion

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AXNT20 KNHC 231223
TWDAT

TROPICAL WEATHER DISCUSSION
NWS TPC/NATIONAL HURRICANE CENTER MIAMI FL
805 AM EDT THU SEP 23 2010

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 DEPRESSION LISA IS CENTERED NEAR 17.7N 29.0W AT 23/0900
UTC OR ABOUT 300 NM WNW OF THE CAPE VERDE ISLANDS MOVING E AT 4
KT. ESTIMATED MINIMUM CENTRAL PRESSURE IS 1005 MB. MAXIMUM
SUSTAINED WIND SPEED IS 30 KT WITH GUSTS TO 40 KT. ALTHOUGH THE
TROPICAL CYCLONE WAS DOWNGRADED TO DEPRESSION STATUS AT 23/0900
UTC...SOME ADDITIONAL STRENGTHENING IS FORECAST DURING THE NEXT
48 HOURS AS THE SYSTEM REMAINS SOUTHWEST OF AN EASTERN ATLC
UPPER LEVEL TROUGH AND WITHIN A MARGINALLY LOW VERTICAL WIND
SHEAR ENVIRONMENT. A NEW BURST OF SCATTERED MODERATE AND
ISOLATED STRONG CONVECTION IS WITHIN 120 NM OF THE CENTER IN THE
EASTERN SEMICIRCLE. SEE LATEST NHC FORECAST/ADVISORY UNDER
AWIPS/WMO HEADERS MIATCMAT4/WTNT24 KNHC FOR MORE DETAILS.

TROPICAL WAVE EXTENDS FROM 10N73W TO 17N72W MOVING W AT 10-15
KT. A 1007 MB LOW IS ANALYZED ALONG THE WAVE AXIS CENTERED NEAR
13N73W. WHILE STRONG NORTHEAST TO EASTERLY FLOW IS OCCURRING AT
THE SURFACE OVER THE EASTERN AND CENTRAL CARIBBEAN SEA N OF THE
LOW CENTER...MODEL GUIDANCE INDICATES A MID-LEVEL..700 MB...
CIRCULATION COINCIDES WITH THE SURFACE LOW. THESE FEATURES ARE
FORECAST TO TRACK WNW OVER THE WESTERN CARIBBEAN SEA THE NEXT
24-36 HOURS. SCATTERED MODERATE AND ISOLATED CONVECTION IS FROM
11N-17N BETWEEN 69W-76W. ANOTHER 90 NM WIDE BAND OF SCATTERED
MODERATE AND ISOLATED STRONG CONVECTION EXTENDS FROM THE
NORTHERN EXTENT OF THE TROPICAL WAVE AXIS NEAR 17N72W TO 12N62W.

...TROPICAL WAVES...

TROPICAL WAVE EXTENDS FROM 09N24W TO 16N22W MOVING W AT 10 KT.
THE WAVE CONTINUES MOVING SLOWLY WESTWARD AND UNDER THE
INFLUENCE OF LOW-LEVEL SOUTHWESTERLY MONSOONAL FLOW FEEDING INTO
NEARBY T.D. LISA. ISOLATED MODERATE CONVECTION IS WITHIN 90 NM
EITHER SIDE OF A LINE FROM 14N25W TO 08N32W.

...ITCZ...

ITCZ AXIS IS ANALYZED ALONG 12N34W 11N53W 12N69W. SCATTERED
MODERATE CONVECTION IS FROM 06N-13N BETWEEN 17W-22W...AND FROM
06N-11N BETWEEN 35W-47W.

...DISCUSSION...

GULF OF MEXICO...
AN UPPER LEVEL ANTICYCLONE IS CENTERED IN THE VICINITY OF THE
TEXAS BIG BEND REGION NEAR 30N101W AND EXTENDS UPPER LEVEL
RIDGING EASTWARD OVER THE NW GULF TO 92W. THIS UPPER LEVEL
FEATURE IS PROVIDING STABLE NORTHEASTERLY FLOW ALOFT OVER THE NW
GULF THIS MORNING. A SECOND UPPER LEVEL RIDGE IMPACTS THE
EASTERN GULF E OF 88W WHICH IS ANCHORED IN THE SW NORTH ATLC
NEAR 22N77W. BETWEEN BOTH THESE ANTICYCLONIC REGIMES...A NARROW
UPPER LEVEL TROUGH IS LOCATED OVER THE CENTRAL GULF BETWEEN
88W-92W WITH A BROAD UPPER LEVEL LOW CENTERED NEAR 25N90W. THE
UPPER LEVEL TROUGH AXIS EXTENDS FROM MOBILE BAY TO THE EASTERN
BAY OF CAMPECHE NEAR 20N93W. AT THE SURFACE...A RIDGE AXIS
EXTENDS FROM THE W ATLC ACROSS NORTHERN FLORIDA TO THE TEXAS
GULF COAST NEAR BROWNSVILLE AND IS PROVIDING MUCH OF THE
-0.GUL       F WITH 15-20 KT E TO SE WINDS. ISOLATED SHOWERS AND
TSTMS CONTINUE ACROSS THE CENTRAL GULF WATERS FROM
21N-27N...STRETCHING FROM THE FLORIDA KEYS WESTWARD TO THE NE
MEXICO GULF COAST.

CARIBBEAN SEA...
AN UPPER LEVEL ANTICYCLONIC CIRCULATION CENTERED IN THE SW NORTH
ATLC NEAR 22N77W EXTENDS AN UPPER LEVEL RIDGE AXIS OVER EASTERN
CUBA TO THE NICARAGUA/HONDURAS BORDER NEAR 14N85W. EASTERLY
UPPER LEVEL FLOW TURNS NORTHERLY OVER THE NW CARIBBEAN AND IS
ADVECTING TROPICAL MOISTURE OVER MUCH OF THE WESTERN CARIBBEAN
AND CUBA THIS MORNING. ATMOSPHERIC INSTABILITY AND CONVERGENT
LOW-LEVEL TRADEWINDS ARE GENERATING A LARGE AREA OF SCATTERED
SHOWERS AND TSTMS FROM 11N-19N BETWEEN 76W-86W. FARTHER EAST
OVER THE CENTRAL CARIBBEAN...THE TROPICAL WAVE ALONG 73W AND
ASSOCIATED 1007 MB LOW PRESSURE CENTERED NEAR 13N73W IS
HIGHLIGHTED IN THE SPECIAL FEATURES SECTION ABOVE. THIS AREA IS
QUICKLY ESCAPING THE INFLUENCE OF AN UPPER LEVEL LOW CENTERED
NORTH OF PUERTO RICO NEAR 20N66W. THIS IN TURN IS PROVIDING THE
TROPICAL WAVE AND LOW A MORE FAVORABLE ENVIRONMENT FOR
DEVELOPING OVER THE NEXT 48 HOURS. UPPER LEVEL DIFFLUENCE S OF
17N IN THE MIDDLE TO UPPER LEVELS AND STRONG EASTERLY TRADES N
OF 14N BETWEEN 65W-80W ARE GENERATING AN AREA OF SCATTERED
SHOWERS AND TSTMS FROM 11N-18N BETWEEN 62W-86W.

ATLANTIC OCEAN...
AN UPPER LEVEL RIDGE AXIS EXTENDS ACROSS THE W ATLC FROM CENTRAL
CUBA NEAR 22N77W NE TO 28N66W. THIS UPPER LEVEL RIDGE IS DRAWING
TROPICAL MOISTURE NORTHWARD ACROSS CUBA AND THE BAHAMAS TO NEAR
BERMUDA. ISOLATED SHOWERS ARE PRIMARILY OVER THE STRAITS OF
FLORIDA REMAINING S OF 26N W OF 77W. FARTHER NORTHEAST...
ISOLATED SHOWERS STREAM W-NW TOWARD THE FLORIDA PENINSULA WITHIN
120 NM EITHER SIDE OF A LINE FROM 24N65W TO 28N80W. THE
REMAINDER OF THE W ATLC IS UNDER THE INFLUENCE OF A BROAD
SURFACE RIDGE LOCATED W OF 45W AND EXTENDING ACROSS THE FLORIDA
PENINSULA INTO THE GULF OF MEXICO. IT REMAINS ANCHORED BY A
QUASI-STATIONARY 1025 MB HIGH CENTERED NEAR 36N57W. A MID-LEVEL
SHORTWAVE TROUGH IS LOCATED NORTH OF THE DISCUSSION AREA ACROSS
THE CENTRAL ATLC WITH AXIS EXTENDING FROM 36N33W TO 30N39W. THIS
TROUGHING SUPPORTS THE REMNANT 1009 MB LOW OF JULIA CENTERED
NEAR 33N38W. WEAK SURFACE TROUGHING EXTENDS SW FROM THE LOW TO
NEAR 27N41W. SCATTERED MODERATE CONVECTION IS FROM 33N-35N
BETWEEN 35W-39W... WHILE ISOLATED SHOWERS LINGERING N OF 28N
BETWEEN 35W-42W. ELSEWHERE OVER THE REMAINDER OF THE EASTERN
ATLC...AN UPPER LEVEL LOW IS CENTERED NEAR 29N24W AND EXTENDS A
TROUGH AXIS FROM THE UPPER LEVEL LOW TO 20N27W. THIS UPPER LEVEL
FEATURE SUPPORTS A WEAK SURFACE TROUGH ANALYZED FROM 21N22W TO
THE WESTERNMOST CANARY ISLANDS NEAR 28N18W. MOIST SOUTHWESTERLY
FLOW ALOFT AND LOW-LEVEL CYCLONIC FLOW IN THE VICINITY OF THE
SURFACE TROUGH IS GENERATING ISOLATED SHOWERS WITHIN 150 NM
EITHER SIDE OF A LINE FROM 20N25W TO 32N19W.

FOR ADDITIONAL INFORMATION PLEASE VISIT
HTTP://WWW.HURRICANES.GOV/MARINE

$$
HUFFMAN




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