[Tropical] Tropical Weather Discussion

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AXNT20 KNHC 241813
TWDAT

TROPICAL WEATHER DISCUSSION
NWS TPC/NATIONAL HURRICANE CENTER MIAMI FL
205 PM EDT MON SEP 24 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 1200 UTC SURFACE ANALYSIS AND SATELLITE IMAGERY
THROUGH 1715 UTC.

...SPECIAL FEATURES...
TROPICAL STORM JERRY WAS DOWNGRADED TO A TROPICAL DEPRESSION
AT 24/1500 UTC BECAUSE SATELLITE CLASSIFICATIONS INDICATED
THAT THE SYSTEM HAD WEAKENED FROM THE STORM STAGE. NOT MUCH
ORGANIZED DEEP CONVECTIVE PRECIPITATION IS PRESENT. IT IS
DOUBTFUL THAT THE SYSTEM IS EVEN A TROPICAL CYCLONE STILL.
THE LOW-LEVEL CIRCULATION IS BECOMING DEFORMED AND ILL-DEFINED.
IT IS POSSIBLE THAT ADVISORIES MAY BE DISCONTINUED THIS AFTERNOON
IF THIS TREND CONTINUES. JERRY OR ITS REMNANTS SHOULD BECOME
ABSORBED BY A LARGE AND POWERFUL EXTRATROPICAL CYCLONE WITHIN
THE NEXT 12 TO 24 HOURS IN ANY EVENT.
THE CENTER OF TROPICAL DEPRESSION JERRY AT 24/1500 UTC WAS NEAR
39.5N 44.5W OR ABOUT 820 NM/1520 KM WEST-NORTHWEST OF THE AZORES.
JERRY IS MOVING NORTHEAST 11 KT. THE MAXIMUM SUSTAINED WIND
SPEEDS ARE 30 KT WITH GUSTS TO 40 KT. THE ESTIMATED MINIMUM
CENTRAL PRESSURE IS 1004 MB. PLEASE READ THE LATEST NHC FORECAST
ADVISORY UNDER AWIPS/WMO HEADERS MIATCMAT1/WTNT21 OR THE PUBLIC
ADVISORY UNDER MIATCPAT1/WTNT31 KNHC FOR MORE DETAILS.

A WELL DEFINED TROPICAL WAVE IS ALONG 58W/59W SOUTH OF 19N
MOVING WEST 10 TO 15 KT. A 1011 MB LOW PRESSURE CENTER IS
ALONG THE WAVE NEAR 12.5N. SCATTERED MODERATE TO STRONG SHOWERS
AND THUNDERSTORMS AROUND THIS WAVE ALREADY ARE REACHING
SAINT LUCIA AND MARTINIQUE. CLOUD COVER AND SHOWERS ALSO MAY
BE REACHING BARBADOS NOW IF THOSE CONDITIONS HAVE NOT BEEN
EXPERIENCED THERE ALREADY EARLIER TODAY. THE CELLS PRODUCING
THIS PRECIPITATION ARE FROM 13N TO 15N BETWEEN 58W AND 61W.
ISOLATED MODERATE SHOWERS ARE ELSEWHERE FROM 10N TO 14N BETWEEN
54W AND 56W...AND FROM 10N TO 13N BETWEEN 56W AND 60W. IT IS
EASILY POSSIBLE THAT THE RAIN FROM THIS TROPICAL WAVE MAY REACH
THE LEEWARD ISLANDS BY TOMORROW AS LONG IT MAINTAINS ITSELF AS
IT IS DOING RIGHT NOW. THIS FEATURE HAS THE POTENTIAL TO DEVELOP
INTO A TROPICAL DEPRESSION DURING THE NEXT DAY OR TWO AS IT
MOVES NORTHWESTWARD 10 TO 15 KT. RESIDENTS IN THE LESSER
ANTILLES SHOULD MONITOR THE PROGRESS OF THIS SYSTEM.

A 1007 MB LOW PRESSURE CENTER IS NEAR 9N34W ABOUT 1520 NM EAST
OF BARBADOS...MOVING WEST 10 TO 15 KT. THIS LARGE SYSTEM
CONTINUES TO SHOW SIGNS OF ORGANIZATION...AND IT MAY BECOME
A TROPICAL DEPRESSION DURING THE NEXT DAY OR SO. SCATTERED
MODERATE TO STRONG SHOWERS AND THUNDERSTORMS FROM 10N TO 12N
BETWEEN 35W AND 37W. OTHER SCATTERED MODERATE SHOWERS TO
ISOLATED STRONG THUNDERSTORMS COVER THE AREA FROM 6N TO 13N
BETWEEN 30W AND 40W.

...TROPICAL WAVES...

A 1014 MB LOW PRESSURE CENTER IS NEAR 14N48W MOVING WEST
10 TO 15 KT. ISOLATED MODERATE SHOWERS FROM 12.5N TO 16.5N
BETWEEN 46W AND 49W.

AN ATLANTIC OCEAN TROPICAL WAVE IS ALONG 39W/40W SOUTH OF
19N MOVING WEST 10 TO 15 KT. THIS WAVE HAS MAINTAINED GOOD
WESTWARD CONTINUITY IN BOTH SATELLITE HOVMOLLER DIAGRAMS
AND THE MIMIC TPW ANIMATION SINCE EMERGING OFF THE COAST
OF AFRICA A FEW DAYS AGO. THE 14N48W LOW PRESSURE SYSTEM
TO THE EAST OF THE WAVE CONTINUES TO OVERTAKE THIS WAVE.
ISOLATED MODERATE SHOWERS FROM 10N TO 12N BETWEEN 37W AND
42W. THIS WAVE MAY NEED TO BE DROPPED OR RELOCATED ALONG
THE BETTER DEFINED LOW JUST TO ITS EAST...WHICH APPEARS
TO BE ABSORBING THE WAVE THAT WE HAVE BEEN TRACKING DURING
THE LAST FEW DAYS.

A WESTERN CARIBBEAN SEA TROPICAL WAVE IS ALONG 87W SOUTH OF 19N
MOVING WEST 10 TO 15 KT. THE WAVE IS NOT EASILY SEEN IN ANY OF
THE AVAILABLE DATA AND CONTINUES TO FOLLOW CONTINUITY FROM
PREVIOUS ANALYSES. UPPER LEVEL NORTHERLY WIND FLOW IS ON TOP OF
THE WAVE. A MIDDLE TO UPPER LEVEL CYCLONIC CIRCULATION CENTER
IS NEAR 15N78W TO THE EAST OF THE WAVE.

...THE ITCZ...
6N10W 7N28W 5N42W 11N56W. SCATTERED MODERATE SHOWERS TO ISOLATED
STRONG THUNDERSTORMS FROM 4N TO 7N BETWEEN 14W AND 24W. WARMING
CLOUD TOP TEMPERATURES AND DEBRIS CLOUDS FROM WEAKENING
CONVECTIVE PRECIPITATION FROM 3N TO 6N BETWEEN 9W AND 14W.
THIS ACTIVITY MAY BE ASSOCIATED WITH THE NEXT TROPICAL WAVE.
ISOLATED MODERATE SHOWERS WITHIN 60 TO 90 NM ON EITHER SIDE
OF 5N38W 6N44W 11N53W.

DISCUSSION...

THE GULF OF MEXICO...
A 1011 MB LOW PRESSURE CENTER IS NEAR 22N93W...ALONG A TROUGH
THAT STRETCHES FROM 19N91W OF THE YUCATAN PENINSULA TO 25N95W
IN THE WESTERN GULF WATERS. NUMEROUS STRONG SHOWERS AND
THUNDERSTORMS FROM 22N TO 24N BETWEEN 90W AND 94W...AND FROM
28N TO 29N BETWEEN 90W AND 92W. ISOLATED MODERATE SHOWERS ARE
ELSEWHERE BETWEEN 90W AND 94W. A MIDDLE TO UPPER LEVEL CYCLONIC
CIRCULATION CENTER IS BEING STRETCHED OUT BY THE FLOW
REGIMES...ALONG THE UPPER TEXAS COAST NEAR 29N95W. A MIDDLE TO
UPPER LEVEL CYCLONIC CIRCULATION CENTER IS FORMING ON TOP OF
SOUTH FLORIDA NEAR 26N81W. AN UPPER LEVEL RIDGE IS IN BETWEEN
THESE TWO AREAS OF CYCLONIC FLOW. WIDELY SCATTERED TO SCATTERED
MODERATE SHOWERS/ISOLATED STRONG THUNDERSTORMS ARE OCCURRING
OVER SOUTH FLORIDA SOUTH OF LAKE OKEECHOBEE...IN THE BAHAMAS
WEST OF 76W NORTH OF CUBA...IN CUBA WEST OF 78W...AND IN THE
SOUTHEASTERN GULF OF MEXICO WITHIN 60 NM ON EITHER SIDE OF THE
LINE FROM WESTERN CUBA TO 27N88W.

THE CARIBBEAN SEA...
STRONG SHOWERS AND THUNDERSTORMS ARE IN THE SOUTHWESTERN CORNER
OF THE AREA...ALONG PANAMA'S NORTHERN COAST...THANKS TO THE ITCZ
AND THE BASE OF A MIDDLE TO UPPER LEVEL TROUGH. THE TROUGH
EXTENDS FROM A CYCLONIC CIRCULATION CENTER NEAR 15N78W...ACROSS
PANAMA...AND EVENTUALLY INTO THE EASTERN PACIFIC OCEAN SOUTH OF
PANAMA. UPPER LEVEL SOUTHWESTERLY WIND FLOW COVERS THE REST OF
THE CARIBBEAN SEA. THE 58W/59W TROPICAL WAVE IS SPREADING STRONG
SHOWERS AND THUNDERSTORMS ACROSS SAINT LUCIA AND MARTINIQUE...
AND BARBADOS. THE LEEWARD ISLANDS SHOULD EXPECT SHOWERS AND
THUNDERSTORMS FROM THIS WAVE IF THE AREAS OF DEEP CONVECTIVE
PRECIPITATION MAINTAIN THEMSELVES AS SUCH FOR THE NEXT
24 TO 36 HOURS. A SURFACE TROUGH PASSES FROM THE ATLANTIC
OCEAN NEAR 24N63W INTO THE EASTERN CARIBBEAN SEA NEAR 16N65W.
ISOLATED MODERATE SHOWERS ARE WITHIN 45 NM ON EITHER SIDE OF
20N61W 17N64W 13N69W.

THE ATLANTIC OCEAN...
A SURFACE TROUGH FROM 30N63W TO 24N63W INTO THE EASTERN
CARIBBEAN SEA NEAR 16N65W. ISOLATED MODERATE SHOWERS ARE
WITHIN 45 NM ON EITHER SIDE OF 20N61W 17N64W 13N69W.
THIS TROUGH IS REALLY OBVIOUS ON VISIBLE SATELLITE IMAGERY.
OTHER SCATTERED MODERATE SHOWERS TO ISOLATED STRONG
THUNDERSTORMS ARE FROM 22N TO 27N BETWEEN 51W AND 60W.
THE CLOUD TOP TEMPERATURES HAVE BEEN WARMING DURING THE
LAST 4 TO 5 HOURS IN THE CLOUD CLUSTERS IN THE EASTERN
PART OF THIS AREA. A MIDDLE TO UPPER LEVEL TROUGH IS ALONG
27N46W BEYOND 34N41W. A SURFACE TROUGH REMAINS...CONNECTED
WITH THIS FEATURE...ALONG 25N54W 28N45W 32N41W. ISOLATED
MODERATE SHOWERS ARE WITHIN 30 TO 45 NM ON EITHER SIDE OF
26N44W BEYOND 31N41W. AN UPPER LEVEL RIDGE IS ALONG 21N43W
TO 27N38W BEYOND 33N36W. A MIDDLE TO UPPER LEVEL TROUGH IS
IN THE EASTERN ATLANTIC OCEAN FROM 19N26W TO 24N24W BEYOND
31N19W. A SURFACE RIDGE IS ALONG 26N38W BEYOND 33N30W.

$$
MT


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