[Tropical] Tropical Weather Discussion

[EMWIN Server]

AXNT20 KNHC 231758
TWDAT

TROPICAL WEATHER DISCUSSION
NWS NATIONAL HURRICANE CENTER MIAMI FL
205 PM EDT WED OCT 23 2013

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...WEATHER OBSERVATIONS...RADAR...AND METEOROLOGICAL
ANALYSIS.

BASED ON 1200 UTC SURFACE ANALYSIS AND SATELLITE IMAGERY THROUGH
1715 UTC.

...SPECIAL FEATURE...
THE CENTER OF TROPICAL STORM LORENZO AT 23/1500 UTC IS NEAR
29.5N 49.0W AND IS MOVING EAST AT 5 KNOTS. THE ESTIMATED MINIMUM
CENTRAL PRESSURE IS 1006 MB. MAXIMUM SUSTAINED WIND SPEED IS 40
KNOTS WITH GUSTS TO 50 KNOTS. PUBLIC ADVISORIES ON LORENZO ARE
ISSUED UNDER WMO HEADER WTNT33 KNHC AND UNDER AWIPS HEADER
MIATCPAT3. FORECAST/ADVISORIES ON LORENZO ARE ISSUED UNDER WMO
HEADER WTNT23 KNHC AND UNDER AWIPS HEADER MIATCMAT3. NUMEROUS
STRONG CONVECTION IS FROM 27N-29N BETWEEN 46W-48W. SCATTERED
MODERATE CONVECTION IS ELSEWHERE FROM 26N-29N BETWEEN 44W-48W.

GALE FORCE WINDS ARE ON THE SW GULF OF MEXICO S OF 21N W OF COLD
FRONT FROM 28N83W TO 25N90W TO 18N95W. IN THIS REGION...NW TO N
WINDS OF 30-35 KT WITH SEAS RANGING FROM 8-13 FT. N-NE NEAR GALE
FORCE WINDS ARE FROM 21N-24N W OF FRONT WITH SEAS RANGING FROM 8-
10 FT. GALE FORCE WINDS ARE FORECAST TO SUBSIDE TONIGHT BUT HIGH
OR NEAR GALE FORCE WINDS ARE EXPECTED THROUGH FRIDAY AFTERNOON.

...TROPICAL WAVES...
A TROPICAL WAVE IS ON THE EASTERN ATLC WITH AXIS EXTENDING FROM
16N21W TO 05N23W AND MOVING WEST AT APPROXIMATELY 5 KT. SSMI
TOTAL PRECIPITABLE WATER IMAGERY INDICATE THE WAVE IS MOSTLY
EMBEDDED WITHIN A MODERATE MOIST ENVIRONMENT WHILE A SECTOR OF
HIGH MOISTURE LIES SE OF THE AXIS. SCATTERED MODERATE CONVECTION
IS FROM 03N-12N BETWEEN 18W-23W...COINCIDING WITH THE AREA OF
HIGH MOISTURE.

TROPICAL WAVE AXIS EXTENDS FROM 10N55W TO 18N55W AND IS MOVING
WEST AT ABOUT 10-15 KT. WATER VAPOR IMAGERY SHOW SUBSIDENCE OF
VERY DRY AIR WITHIN THE WAVE ENVIRONMENT WHICH IS HINDERING
CONVECTION AT THIS TIME.

TROPICAL WAVE IS OVER THE WESTERN CARIBBEAN WITH AXIS EXTENDING
FROM 08N82W TO 20N82W AND MOVING W NEAR 10 KT. WATER VAPOR
IMAGERY SHOW DRY AIR SUBSIDING IN THE NORTHERN SECTOR OF THE
WAVE N OF 15N WHICH IS SUPPRESSING CONVECTION IN THE NW
CARIBBEAN BASIN. IN THE SOUTHERN BASIN...A MOISTURE MAXIMUM IS
OBSERVED IN THE SSMI TOTAL PRECIPITABLE WATER IMAGERY. SCATTERED
MODERATE CONVECTION AND ISOLATED TSTMS MOSTLY ASSOCIATED WITH
THE MONSOON TROUGH ARE S OF 15N BETWEEN 70W-84W.

...THE ITCZ/THE MONSOON TROUGH...
A TROPICAL WAVE IS DISRUPTING THE MONSOON TROUGH IN THE EASTERN
ATLC. THE ITCZ EXTENDS WEST OF THE WAVE FROM 08N26W TO 03N34W TO
05N42W. BESIDES THE CONVECTION ASSOCIATED WITH THE TROPICAL
WAVE...SCATTERED MODERATE CONVECTION IS FROM 07N-10N BETWEEN 24W-
32W. SIMILAR CONVECTION IS FROM 0N-09N BETWEEN 33W-43W.

...DISCUSSION...

THE GULF OF MEXICO...
A MIDDLE TO UPPER LEVEL TROUGH WITH AXIS EXTENDING FROM THE
UPPER GREAT LAKES TO THE SOUTHERN GULF SUPPORTS A PAIR OF COLD
FRONTS. THE FIRST COLD FRONT EXTENDS FROM THE SW N ATLC TO
CENTRAL FLORIDA TO 27N82W AND THEN SW IN THE GULF ALONG 25N88W
TO 18N94W IN THE BAY OF CAMPECHE. A REINFORCING COLD FRONT
EXTENDS FROM EASTERN TALLAHASSEE TO 29N85W 26N92W TO EASTERN
MEXICO NEAR 23N97W. GALE FORCE WINDS ARE IN THE SW GULF W OF 92W
BETWEEN THE TWO FRONTAL BOUNDARIES. A PRE-FRONTAL SURFACE TROUGH
IS IN THE BAY OF CAMPECHE FROM 23N90W TO 18N91W. UPPER-LEVEL
DIVERGENCE IN THE BAY OF CAMPECHE IS SUPPORTING A CLUSTER OF
MODERATE CONVECTION AND TSTMS S OF 22N BETWEEN 90W-94W. WATER
VAPOR IMAGERY SHOW THAT DIVERGENT FLOW ASSOCIATED WITH TROPICAL
STORM RAYMOND IN THE EAST PACIFIC IS ADVECTING SOME  MOISTURE TO
THE CENTRAL-SOUTHERN GULF...WHICH IS SUPPORTING A SWATH OF
ISOLATED SHOWERS BETWEEN THE TWO FRONTS AND IN THE SE BASIN.

THE REINFORCING COLD FRONT WILL OVERTAKE THE FRONT AHEAD OF IT
AND WILL CONTINUE TO DRIFT E-SE TO EXTEND ACROSS SOUTHERN
FLORIDA TONIGHT. LATER TODAY THE PORTION OF THE FRONT OVER THE
GULF IS EXPECTED TO BECOME STATIONARY. GALE FORCE WINDS ARE
FORECAST TO SUBSIDE TONIGHT BUT HIGH WINDS ARE EXPECTED THROUGH
FRIDAY AFTERNOON.

THE CARIBBEAN SEA...
A TROPICAL WAVE IS OVER THE WESTERN CARIBBEAN WITH AXIS
EXTENDING FROM 08N82W TO 20N82W AND MOVING W NEAR 10 KT. WATER
VAPOR IMAGERY SHOW DRY AIR SUBSIDING IN THE NORTHERN SECTOR OF
THE WAVE N OF 15N WHICH IS SUPPRESSING CONVECTION IN THE NW
CARIBBEAN BASIN. IN THE SOUTHERN BASIN...A MOISTURE MAXIMUM IS
OBSERVED IN THE SSMI TOTAL PRECIPITABLE WATER IMAGERY. SCATTERED
MODERATE CONVECTION AND ISOLATED TSTMS MOSTLY ASSOCIATED WITH
THE MONSOON TROUGH ARE S OF 15N BETWEEN 70W-84W. A MIDDLE TO
UPPER LEVEL LOW IS CENTERED OVER THE WINDWARD PASSAGE AND
SUPPORTS A SURFACE TROUGH FROM THE SOUTHERN BAHAMAS NEAR 22N72W
TO 17N75W. ISOLATED SHOWERS AND TSTMS ARE ACROSS SOUTHEASTERN
BAHAMAS...THE WINDWARD PASSAGE...EASTERN CUBA AND JAMAICA. A
SURFACE TROUGH IS SE OF PUERTO RICO FROM 17N64W TO 13N64W. A
CLUSTER OF HEAVY SHOWERS AND TSTMS ASSOCIATED WITH THIS TROUGH
HAS DEVELOPED WITHIN THE LAST COUPLE OF HOURS FROM 13N-16N
BETWEEN 65W-68W.

THE TROPICAL WAVE WILL CONTINUE TO DRIFT WESTWARD AND IS
EXPECTED TO MOVE ACROSS CENTRAL AMERICA TONIGHT. THE SURFACE
TROUGH IN THE EASTERN BASIN IS FORECAST TO MOVE W AND DISSIPATE
LATER TODAY. A NEW TROPICAL WAVE WILL BE MOVING ACROSS THE
LESSER ANTILLES FRIDAY NIGHT.

HISPANIOLA...
A MIDDLE TO UPPER LEVEL LOW IS CENTERED OVER THE WINDWARD
PASSAGE AND SUPPORTS A SURFACE TROUGH FROM THE SOUTHERN BAHAMAS
NEAR 22N72W TO ADJACENT WATERS SW OF HAITI NEAR 17N75W. ISOLATED
SHOWERS AND TSTMS ARE OVER THE WINDWARD PASSAGE. ISOLATED
SHOWERS ARE LIKELY ACROSS THE ISLAND AND ADJACENT WATERS THROUGH
TONIGHT. THESE SHOWERS WILL CONTINUE TO DISPLACE W-NW AS THE
UPPER-LEVEL LOW DRIFTS IN THAT DIRECTION. A DRY AIRMASS IS
EXPECTED TO ENTER THE DOMINICAN REPUBLIC BY EARLY THURSDAY WHICH
WILL LIKELY HELP TO SUPPRESS CONVECTIVE ACTIVITY.

THE ATLANTIC OCEAN...
A MIDDLE TO UPPER LEVEL TROUGH WITH AXIS EXTENDING FROM THE
UPPER GREAT LAKES TO THE SOUTHERN GULF SUPPORTS A COLD FRONT
THAT ENTERS THE SW N ATLC NEAR 30N77W TO CAPE CANAVERAL...SW
THROUGH CENTRAL FLORIDA AND THE SOUTHERN GULF. ISOLATED SHOWERS
AND TSTMS ARE ACROSS THE NORTHERN BAHAMAS. A MIDDLE TO UPPER
LEVEL LOW IS CENTERED OVER THE WINDWARD PASSAGE AND SUPPORTS A
SURFACE TROUGH FROM THE SOUTHERN BAHAMAS NEAR 22N72W TO ADJACENT
WATERS SW OF HAITI NEAR 17N75W. ISOLATED SHOWERS AND TSTMS ARE
ACROSS SE BAHAMAS. TROPICAL STORM LORENZO IS IN THE CENTRAL
ATLC. SEE THE SPECIAL FEATURES SECTION ABOVE FOR MORE
INFORMATION. FURTHER EAST...SE OF LORENZO...A 1019 MB HIGH
PRESSURE CENTER IS NEAR 26N38W...WHICH IS EXPECTED TO MERGE WITH
ANOTHER HIGH PRESSURE CENTER NORTHWARD WITHIN THE NEXT 24 HOURS.

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

$$
NR


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