[Tropical] Tropical Weather Discussion

[EMWIN Server]

AXNT20 KNHC 060538
TWDAT

TROPICAL WEATHER DISCUSSION
NWS TPC/NATIONAL HURRICANE CENTER MIAMI FL
205 AM EDT SAT OCT 06 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 0500 UTC.

...TROPICAL WAVES...

TROPICAL WAVE IS IN THE CENTRAL ATLANTIC ALONG 49W S OF 18N
MOVING W 10 KT OVER THE PAST 24 HOURS. AN ILL-DEFINED 1010 MB
LOW IS ALONG THE WAVE AXIS NEAR 12N. THIS WAVE REMAINS STRONGLY
SHEARED UNDER THE INFLUENCE OF SWIFT UPPER SOUTHWESTERLY WINDS
TO THE E OF COMPLEX TROUGHING. THIS SHEAR HAS STAGGERED THE
ASSOCIATED SCATTERED SHOWERS AND ISOLATED TSTMS TO THE E OF THE
WAVE AXIS WITHIN 360 NM. MORE ORGANIZED CLUSTERS OF TSTMS ARE TO
THE N AND NE OF THE WAVE IN AN UPPER DIFFLUENT ZONE.

...THE ITCZ...
AXIS CENTERED ALONG 8N13W 6N20W 8N40W 9N48W 9N61W. SCATTERED
MODERATE CONVECTION IS WITHIN 75 NM N OF THE AXIS BETWEEN
31W-37W.

DISCUSSION...

THE GULF OF MEXICO...
THE AREA OF LOW PRES THAT WE HAVE BEEN TRACKING FOR SEVERAL DAYS
HAS NOW MOVED INLAND OVER SE TEXAS. MOST OF THE SHOWER AND TSTM
ACTIVITY HAS NOW DIMINISHED WITH DOPPLER RADAR ONLY DEPICTING A
A FEW SHOWERS IN VERY CLOSE TO THE CENTER. THE MORE ACTIVE AREA
IS IN THE EXTREME SE GULF AND OVER CENTRAL AND SOUTH FLORIDA.
DOPPLER RADAR IN THIS AREA IS SHOWING A CONCENTRATION OF SHOWER
AND TSTM ACTIVITY OVER THE CENTRAL WEST COAST OF THE STATE.
SMALLER QUICK MOVING SHOWERS LIE ACROSS THE REMAINDER OF THE
REGION S OF 29N E OF 84W. THIS ACTIVITY IS ASSOCIATED WITH LOW
LEVEL CONVERGENCE NEAR AN ATLC SFC TROUGH AND A MID TO UPPER
LEVEL DISTURBANCE. THE REMAINDER OF THE REGION IS FAIRLY QUIET
UNDER THE INFLUENCE OF UPPER RIDGING RUNNING N-S ALONG 91W WITH
WIDESPREAD STABLE SINKING AIR. A MID TO UPPER LEVEL LOW LIES
ABOVE CENTRAL MEXICO GENERATING TSTM ACTIVITY OVER THE NW PART
OF THE COUNTRY.

THE CARIBBEAN SEA...
COMPLEX ELONGATED LOW-LEVEL TROUGHING PATTERN IS SET UP ACROSS
THE CARIBBEAN THIS EARLY MORNING. ONE TROUGH IS ANALYZED FROM
THE NRN TIP OF COLOMBIA TO WRN CUBA WITH SOME EVIDENCE OF A WEAK
LOW ALONG THE TROUGH IN THE NW CARIB. THE OTHER EXTENDS FROM N
OF PUERTO RICO WWD ACROSS THE N COAST OF HISPANIOLA...CUBA AND
THEN INTO THE FLA STRAITS. IN THE MID AND UPPER LEVELS RIDGING
DOMINATES MUCH OF THE BASIN EXTENDING SE FROM THE HIGH IN THE
CENTRAL GOMEX. THE FLOW IS WEAK IN THE ERN CARIB TO THE S OF AN
UPPER LOW LOCATED N OF THE DOMINICAN REPUBLIC. THIS OVERALL
PATTERN IS PRODUCING A LOT OF CLOUDINESS ACROSS THE REGION.
HOWEVER...DEEP MOISTURE IS NOT VERY ABUNDANT AT THE MOMENT. IR
IMAGERY AND LIGHTNING DATA SHOW THE STRONGEST CLUSTERS OF TSTMS
OVER AND JUST S OF CUBA N OF 20N BETWEEN 78W-83W. SIMILAR
CONVECTIVE ACTIVITY IS IN THE S CARIB S OF 15N BETWEEN 70W-73W
POSSIBLY ENHANCED BY THE SAME SRN LOW-LEVEL TROUGH. SAN JUAN
DOPPLER RADAR IS SHOWING MOST OF THE ORGANIZED ACTIVITY WELL N
OF THE AREA IN THE ATLC ASSOCIATED WITH THE NRN TROUGH. MORE ON
THIS IN THE ATLANTIC SECTION BELOW. BOTH OF THESE SYSTEMS ARE
BEING MONITORED FOR FURTHER DEVELOPMENT.

THE TRADE WIND FLOW IS SIGNIFICANTLY INTERRUPTED ACROSS THE
CARIB DUE TO THE PRESCIENCE OF THE SFC BOUNDARIES. THESE MAINLY
LIGHT AND CHANGEABLE WINDS ARE EXPECTED TO PERSIST ACROSS THE
BULK OF THE AREA OVER THE NEXT DAY OR SO.

THE ATLANTIC OCEAN...
AN ELONGATED TROUGH DOMINATES THE SW PORTION OF THE AREA. THE
SFC TROUGH IS ANALYZED FROM THE FLORIDA STRAITS EWD TO 19N63W.
ONE VORTICITY MAX...LIKELY IN THE MID LEVELS IS OVER FLORIDA BUT
THE MAIN SYSTEM IS MUCH FURTHER E JUST N OF THE MONA PASSAGE.
THIS BOUNDARY COUPLED WITH AN UPPER LOW NEAR 21N70W IS PRODUCING
SCATTERED SHOWERS AND TSTMS S OF 24N BETWEEN 60W-70W.
UPPER-LEVEL WINDS ARE BECOMING MORE FAVORABLE FOR DEVELOPMENT
...AND FURTHER ORGANIZATION OF THIS SYSTEM IS POSSIBLE OVER THE
NEXT COUPLE OF DAYS AS IT MOVES SLOWLY NORTHWARD. THE TIGHTENED
PRES GRADIENT BETWEEN THIS E-W TROUGHING AND HEALTHY RIDGING OFF
THE MID-ATLANTIC COASTLINE IS PRODUCING MODERATE TO STRONG ELY
WINDS AND STEEP WIND WAVES/SWELL N OF 25N W OF 50W.

FARTHER E IN THE E AND CENTRAL ATLC...A LARGE STRETCHED OUT SFC
TROUGH...OLD FRONTAL ZONE...IS ANALYZED ALONG 32N17W 26N30W
27N48W 24N55W. THE COMBINATION OF SPEED CONVERGENCE NEAR THIS
BOUNDARY...A TROPICAL WAVE TO ITS S ALONG 49W AND INSTABILITY
ALOFT NEAR A TROUGH ALONG 53W/54W IS PRODUCING SCATTERED
MODERATE CONVECTION FROM 20N-26N BETWEEN 45W-52W. STRONG UPPER
WLY WINDS E OF THE TROUGH IS SPREADING DEBRIS MOISTURE INTO THE
E ATLC N OF 25N W OF 25W. THE REMAINDER OF THE E ATLC IS MUCH
QUIETER...WITH STABLE CONDITIONS UNDER UPPER RIDGING AND A PAIR
OF WEAK SFC HIGHS ANALYZED NEAR 30N33W AND 23N29W.

$$
CANGIALOSI


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