[Tropical] Tropical Weather Discussion

[EMWIN Server]

AXNT20 KNHC 131105
TWDAT

TROPICAL WEATHER DISCUSSION
NWS TPC/NATIONAL HURRICANE CENTER MIAMI FL
805 AM EDT SAT AUG 13 2005

TROPICAL WEATHER DISCUSSION FOR NORTH AMERICA...CENTRAL
AMERICA...GULF OF MEXICO...CARIBBEAN SEA...NORTHEASTERN
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 0600 UTC SURFACE ANALYSIS AND
SATELLITE IMAGERY THROUGH 1045 UTC.

...SPECIAL FEATURES...

THE CENTER OF TROPICAL STORM IRENE AT 13/0900 UTC WAS NEAR
30.1N 68.6W OR ABOUT 270 MILES/435 KM WEST-SOUTHWEST OF BERMUDA
AND ABOUT 535 MILES/860 KM SOUTHEAST OF CAPE HATTERAS NORTH
CAROLINA. IT WAS MOVING NORTHWEST 9 KT. THE ESTIMATED MINIMUM
CENTRAL PRESSURE 997 MB. THE MAXIMUM SUSTAINED WIND SPEEDS WERE
60 KT WITH GUSTS TO 75 KT. SEE THE LATEST NHC FORECAST/ADVISORY
UNDER AWIPS/WMO HEADERS MIATCMAT4/WTNT24 KNHC OR MIATCPAT4/
WTNT34 KNHC FOR MORE DETAILS. THE CLOUD TOP TEMPERATURES HAVE
BEEN WARMING WITH IRENE SINCE THE LAST TROPICAL WEATHER
DISCUSSION NEARLY FIVE HOURS AGO. SCATTERED MODERATE TO ISOLATED
STRONG SHOWERS AND THUNDERSTORMS EXIST FROM 29N TO 31N BETWEEN
68W AND 71W. IT STILL IS FORECAST TO REACH HURRICANE STRENGTH
DURING THE NEXT 24 HOURS.

A 1011 MB ATLANTIC OCEAN LOW PRESSURE CENTER WAS NEAR 13N43W
MOVING WEST-NORTHWEST 10 TO 15 KT. IT IS POSSIBLE THAT THIS
FEATURE MAY BECOME A TROPICAL CYCLONE DURING THE NEXT 24 HOURS.
WIDELY SCATTERED TO SCATTERED MODERATE/ISOLATED STRONG SHOWERS
AND THUNDERSTORMS FROM 11N TO 15N BETWEEN 41W AND 45W. UPPER
LEVEL WINDS ARE FAVORABLE FOR DEVELOPMENT...ALTHOUGH A MIDDLE
TO UPPER LEVEL TROUGH WITH ITS BASE NEAR 17N50W IS APPROACHING
THE LOW CENTER SLOWLY.

...TROPICAL WAVES...

AN EASTERN ATLANTIC OCEAN TROPICAL WAVE IS PASSING THROUGH THE
CAPE VERDE ISLANDS ALONG 24W/25W SOUTH OF 21N MOVING WEST 10 TO
15 KT DURING THE LAST 24 HOURS. A 1011 MB LOW PRESSURE CENTER
WAS ALONG THE WAVE FROM 15N TO 15.5N. A LARGE STRATOCUMULUS
SWIRL SURROUNDS THE LOW. NO DEEP SHOWERS AND THUNDERSTORMS ARE
NEAR THE LOW CENTER. ANY SIGNIFICANT PRECIPITATION IS IN THE
ITCZ.

AN EASTERN CARIBBEAN SEA TROPICAL WAVE IS ALONG 63W/64W SOUTH OF
18N MOVING WEST 20 KT DURING THE LAST 24 HOURS. THE SHOWERS WITH
THE COMPARATIVELY COLDEST CLOUD TOP TEMPERATURES WERE FOUND FROM
14N TO 15N BETWEEN 66.5W AND 67.5W. OTHER ISOLATED MODERATE
SHOWERS ARE ELSEWHERE FROM 12N TO 18N BETWEEN 63W AND 70W.
UPPER LEVEL ANTICYCLONIC WIND FLOW IS IN THIS AREA.

A CARIBBEAN SEA TROPICAL WAVE IS ALONG 73W SOUTH OF 19N FROM
HAITI TO NORTHERN COLOMBIA...MOVING WEST 15 KT. THE SHOWERS AND
THUNDERSTORMS TO THE WEST OF THIS WAVE FROM THE WINDWARD PASSAGE
TO JAMAICA AND THE CAYMAN ISLAND TO SOUTH OF THE ISLE OF YOUTH
PROBABLY ARE MORE THAN ANYTHING RELATED TO THE BAHAMAS-TO-
JAMAICA MIDDLE TO UPPER LEVEL TROUGH AS RATHER THAN BEING
ASSOCIATED WITH THE WAVE.

A TROPICAL WAVE ALONG WAS 97W/98W SOUTH OF 17N ALONG THE MEXICO
COAST WEST OF THE GULF OF TEHUANTEPEC. NUMEROUS STRONG SHOWERS
AND THUNDERSTORMS ARE OCCURRING IN INTERIOR MEXICO JUST WEST OF
THE ISTHMUS OF TEHUANTEPEC AND THE SOUTHWESTERN GULF OF MEXICO
WATERS FROM 17N TO 20N BETWEEN 94W AND 96W.

...THE ITCZ...

ITCZ 15N17W 13N23W...13N27W 12N40W...11N48W 12N61W. ISOLATED
MODERATE SHOWERS FROM 6N TO 12N BETWEEN AFRICA AND 33W...AND
FROM 8N TO 11N BETWEEN 47W AND 58W.

...DISCUSSION...

THE GULF OF MEXICO...
PERSISTENT CUT-OFF LOW IS OVER THE SE UNITED STATES OVER
MISSISSIPPI...WITH A TROUGH SSW ACROSS LOUISIANA TO THE MEXICAN
COAST NEAR 23N98W. WIDELY SCATTERED MODERATE TO ISOLATED STRONG
SHOWERS AND THUNDERSTORMS EAST OF 95W. STRONG SHOWERS AND
THUNDERSTORMS IN THE SOUTHWESTERN CORNER OF THE AREA WITH THE
97W/98W TROPICAL WAVE. NARROW MID/UPPER LEVEL RIDGE IS OVER THE
EASTERN GULF FROM THE YUCATAN PENINSULA TO THE FLORIDA BIG BEND.
LITTLE SIGNIFICANT CHANGE IS LIKELY WITH THE BROAD LOW NEARLY
STATIONARY...ENHANCING DAILY TSTMS IN THE GULF WATERS.

THE CARIBBEAN SEA...
SHOWERS AND THUNDERSTORMS ARE WITH THE 63W/64W TROPICAL WAVE.
UPPER TROUGH EXTENDS FROM E CENTRAL CUBA THRU JAMAICA TO NEAR
13N79W...MOVING SLOWLY WESTWARD. ISOLATED TSTMS ARE OCCURRING
NORTH OF 18N BETWEEN THE WINDWARD PASSAGE THE YUCATAN CHANNEL.
MIDDLE TO UPPER LEVEL RIDGE IS ESTABLISHED IN THE EASTERN
CARIBBEAN SEA...WITH AN ANTICYCLONIC CIRCULATION NOTED OVER THE
LEEWARD ISLANDS. SOUTHERLY WIND FLOW BETWEEN THE RIDGE AND THE
WESTERN CARIBBEAN CYCLONIC CENTER IS PUSHING HIGH LEVEL MOISTURE
NORTHWARD FROM SOUTH AMERICA ACROSS THE CARIBBEAN SEA TO
HISPANIOLA. UPPER DIFFLUENCE ASSOCIATED WITH THE RIDGE AND
ANTICYCLONE WAS SUPPORTING SCATTERED TSTMS ASSOCIATED WITH
TROPICAL WAVE OVER THE ISLANDS YESTERDAY.

THE ATLANTIC OCEAN...
ONE WESTERN ATLANTIC OCEAN UPPER LEVEL CYCLONIC CIRCULATION
CENTERS IS IN THE NORTHERN BAHAMAS NEAR 25N77W...SOUTH OF
TROPICAL STORM IRENE. THIS CYCLONIC CENTER MARKS THE NORTHERN
EXTENT OF THE WESTERN CARIBBEAN SEA UPPER TROUGH. ANOTHER
CYCLONIC CENTER...SOUTHWEST OF T.S. IRENE...IS ROTATING
NORTHWARD OVER THE CIRCULATION OF IRENE NEAR 27N68W. SUBSIDENCE
WITH THE LOW NEAR 27N68W IS LIMITING SHOWER AND THUNDERSTORM
ACTIVITY AND OUTFLOW IN THE SOUTHERN QUADRANT OF IRENE...WITH
GENERAL SOUTHEASTERLY WIND FLOW ALOFT IN THE TROPICAL CYCLONE.
UPPER LEVEL RIDGE STRETCHES FROM ONE ANTICYCLONIC CIRCULATION
CENTER EAST OF BERMUDA TO THE LESSER ANTILLES ANTICYCLONE OVER
THE LESSER ANTILLES. A RATHER DEEP MID-OCEANIC TROUGH IS SETTING
UP IN THE CENTRAL ATLC FROM A LOW NEAR 30N42W SOUTH-SOUTHWESTWARD
TO 17N50W. THE TROUGH IS FORECAST TO REMAIN NEARLY STATIONARY
BUT DIG SOUTHWESTWARD TO 15N52W IN ABOUT 24 HOURS. THIS COULD
AFFECT THE FUTURE DEVELOPMENT OF THE SURFACE LOW NEAR 13N43W.
ONE 1016 MB SURFACE LOW PRESSURE CENTER IS NEAR 30N42W. WIDELY
SCATTERED MODERATE SHOWERS AND ISOLATED THUNDERSTORMS ARE FOUND
FROM 27N TO 29N BETWEEN 38W AND 45W. A 1016 MB SURFACE LOW
PRESSURE CENTER IS NEAR 28N45W AND IT IS DRIFTING SOUTHWESTWARD.
BROAD UPPER LEVEL CYCLONIC FLOW FROM A TROUGH COVERS THE FAR
NORTHERN PART OF THE EAST CENTRAL ATLANTIC OCEAN NORTH OF 28N
BETWEEN 25W AND 35W. MUCH OF THE EASTERN ATLANTIC OCEAN IS
DOMINATED BY HIGH PRESSURE ALOFT. ONE CENTER IS NEAR 19N33W AND
THE OTHER OVER W AFRICA NEAR 21N12W. BETWEEN THE TWO HIGHS...A
WEAK TROUGH/COL REGION EXTENDS FROM 24N23W TO 13N27W. THIS COL
REGION MARKS THE LEADING EDGE OF THE MOISTURE SURGE ASSOCIATED
WITH THE TROPICAL WAVE AND LOW PRES ALONG 22W/23W. A RIDGE WILL
BECOME ESTABLISHED EAST OF 30W AS THE HIGH NEAR 19N33W
WEAKENS...KEEPING EASTERLY FLOW AND LIGHT SHEAR ACROSS THE FAR
EASTERN ATLANTIC OCEAN. THE SHEAR WILL INCREASE GRADUALLY WEST
OF 30W IN ASSOCIATION WITH THE SOUTHERN PART OF THE MID-OCEANIC
TROUGH FROM 20N50W TO 15N52W.

$$
MT



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