[Tropical] Tropical Weather Discussion

[EMWIN Server]

AXNT20 KNHC 272342
TWDAT

TROPICAL WEATHER DISCUSSION
NWS TPC/NATIONAL HURRICANE CENTER MIAMI FL
805 PM EDT TUE OCT 27 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 1800 UTC SURFACE ANALYSIS AND SATELLITE IMAGERY THROUGH
2315 UTC.

...TROPICAL WAVES...

TROPICAL WAVE EXTENDS FROM 16N25W TO 13N27W TO 8N27W MOVING W
NEAR 10 KT. SATELLITE IMAGERY INDICATES CYCLONIC LOW-LEVEL FLOW
ALONG THE WAVE AXIS FOCUSED NEAR 13N. THIS ALSO COINCIDES WITH
CIMSS WAVETRAK 850 MB RELATIVE VORTICITY MODEL GUIDANCE WHICH
COVERS THE AREA FROM 10N-15N BETWEEN 22W-28W. TOTAL PRECIPITABLE
WATER IMAGERY DEPICTS A MAXIMUM IN DEEP LAYER MOISTURE FROM
8N-20N E OF 30W WHICH ALSO ENCOMPASSES THE WAVE. SCATTERED
MODERATE CONVECTION IS FROM 11N-18N BETWEEN 19W-28W. THIS
CONVECTION IS LARGELY BEING SHEARED TO THE NE OF THE WAVE AXIS
DUE TO AN UPPER LEVEL TROUGH DIGGING SOUTHWARD BETWEEN 20W-30W N
OF 17N OVER THE NE ATLC.

TROPICAL WAVE IS ALONG 48W S OF 16N MOVING W NEAR 12 KT. CIMSS
WAVETRACK MODEL GUIDANCE DEPICTS AN AREA OF MAXIMUM 850 MB
RELATIVE VORTICITY NEAR THE WAVE AXIS FROM 5N-10N BETWEEN
45W-52W. SATELLITE IMAGERY INDICATES BROAD CYCLONIC FLOW IN THE
VICINITY OF THE WAVE AXIS WITH MOST MOISTURE REMAINING EMBEDDED
WITHIN THE ITCZ AXIS ALONG 9N. NO DEEP CONVECTION IS OBSERVED
HOWEVER SCATTERED SHOWERS ARE FROM 5N-11N BETWEEN 45W-51W.

TROPICAL WAVE IS ALONG 61W S OF 17N MOVING W NEAR 13 KT. THE
WAVE COINCIDES WITH A MAXIMUM IN DEEP LAYER MOISTURE AS OBSERVED
IN TOTAL PRECIPITABLE WATER IMAGERY ACROSS THE EASTERN PORTION
OF THE TROPICAL NORTH ATLC. CURRENTLY SCATTERED SHOWERS AND
ISOLATED MODERATE CONVECTION IS FROM 14N-18N BETWEEN 58W-62W AND
IMPACTING THE LEEWARD ISLANDS THIS EVENING. THIS ACTIVITY IS
LIKELY BEING ENHANCED BY UPPER DIFFLUENT FLOW ALOFT DUE TO AN
UPPER LEVEL LOW CENTERED OVER THE N/CENTRAL CARIBBEAN NEAR
17N70W.

...ITCZ...

THE ITCZ AXIS IS CENTERED ALONG 9N13W 10N25W 9N29W 9N46W 9N49W
10N59W. SCATTERED MODERATE/ISOLATED STRONG CONVECTION IS ALONG
THE W AFRICA COAST FROM 6N-11N BETWEEN 8W-14W.

...DISCUSSION...

GULF OF MEXICO...
A COLD FRONT EXTENDS INTO THE GULF FROM SOUTHERN MISSISSIPPI
NEAR 30N89W ALONG 27N90W TO 24N93W WHERE IT CONTINUES STATIONARY
S ALONG 20N94W INTO SOUTHERN MEXICO NEAR 18N94W. ISOLATED
SHOWERS ARE WITHIN 200 NM EITHER SIDE OF THE FRONT. SCATTERED
SHOWERS AND ISOLATED TSTMS ARE ALSO WELL EAST OF THE FRONT
FOCUSED ALONG A LOW-LEVEL CONVERGENCE BOUNDARY OCCURRING WITHIN
90 NM EITHER SIDE OF A LINE FROM JACKSONVILLE FLORIDA SW TO THE
YUCATAN PENINSULA NEAR 19N89W. THIS FRONTAL SYSTEM IS SUPPORTED
ALOFT BY MOIST SWLY FLOW BETWEEN AN UPPER LEVEL TROUGH OVER THE
SOUTHERN U.S. PLAINS AND AN UPPER LEVEL RIDGE EXTENDING FROM
NORTHERN GUATEMALA NE OVER THE YUCATAN CHANNEL AND SOUTHERN
FLORIDA PENINSULA INTO THE W ATLC NEAR 28N78W. AS THE COLD FRONT
MOVES EASTWARD AND BECOMES MORE DIFFUSE OVER THE NE GULF BY
WEDNESDAY...SOUTHERLY RETURN FLOW IS EXPECTED AGAIN ACROSS THE
WESTERN GULF AHEAD OF THE NEXT DEVELOPING COLD FRONT TO ENTER
THE NW GULF LATE THURSDAY.

CARIBBEAN SEA...
A MAJORITY OF THE CARIBBEAN SEA IS EXPERIENCING GENERALLY FAIR
WEATHER THIS EVENING DUE IN PART TO AN UPPER LEVEL LOW CENTERED
SOUTH OF HISPANIOLA NEAR 17N70W. THIS UPPER LEVEL LOW IS
PROVIDING GENERALLY DRY NLY UPPER LEVEL FLOW W OF 73W ACROSS THE
NW CARIBBEAN. UPPER LEVEL DIFFLUENCE S OF 13N W OF 75W
HOWEVER...IS GENERATING SCATTERED SHOWERS AND ISOLATED TSTMS
OVER THE SW CARIBBEAN...INCLUDING PANAMA...COSTA RICA AND
SOUTHERN NICARAGUA. EAST OF THE UPPER LEVEL LOW...UPPER LEVEL
DIFFLUENCE IS GENERATING ISOLATED SHOWERS N OF 16N E OF 70W.
THIS UPPER LEVEL DIFFLUENT PATTERN IS ALSO ENHANCING THE SHOWER
ACTIVITY ASSOCIATED WITH THE TROPICAL WAVE ALONG 61W. MODERATE
TO FRESH TRADEWINDS ARE OBSERVED ACROSS THE MAJORITY OF THE
BASIN THIS EVENING.

ATLANTIC OCEAN...
A WARM FRONT ENTERS THE FAR NW PORTION OF THE DISCUSSION AREA
ACROSS THE W ATLC NEAR 32N79W AND EXTENDS WSW TO INLAND OVER
SOUTHERN GEORGIA NEAR 31N81W. SCATTERED SHOWERS ARE N OF 28N W
OF 79W MAINLY SOUTH OF THE WARM FRONT ACROSS THE NORTHERN
FLORIDA PENINSULA. THE FRONT IS SUPPORTED LARGELY BY AN AREA OF
UPPER LEVEL DIFFLUENCE THAT COVERS MUCH OF THE NE GULF OF MEXICO
ACROSS NORTHERN FLORIDA AND INTO THE FAR W ATLC. AN UPPER LEVEL
RIDGE AXIS IS TO THE E EXTENDING FROM THE SOUTHERN FLORIDA
PENINSULA NE TO BEYOND 32N75W. THIS UPPER RIDGE ALSO EXTENDS A
RIDGE AXIS EASTWARD ALONG 27N THAT SUPPORTS A BROAD SURFACE
RIDGE COVERING THE MAJORITY OF THE CENTRAL ATLC ANCHORED BY A
1020 MB HIGH CENTERED NEAR 30N64W. A COLD FRONT LIES NORTH OF
THE SURFACE RIDGE ALONG 32N BETWEEN 45W-62W. WIDELY SCATTERED
SHOWERS ARE WITHIN 90 NM EITHER SIDE OF THE FRONT AND CONTINUE
TO BECOME MORE DIFFUSE REACHING 30N. FARTHER E...A DISSIPATING
COLD FRONT EXTENDS FROM 22N28W TO 28N20W TO BEYOND 32N19W.
POSSIBLE ISOLATED SHOWERS ARE WITHIN 75 NM E OF THE BOUNDARY. A
SHORTWAVE UPPER LEVEL TROUGH WITH AXIS ALONG 32N19W TO 19N30W
SUPPORTS THE FRONT AS IT MOVES ACROSS THE NE ATLC.

$$
HUFFMAN





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