[Tropical] Tropical Weather Discussion

[EMWIN Server]

AXNT20 KNHC 091750
TWDAT

TROPICAL WEATHER DISCUSSION
NWS NATIONAL HURRICANE CENTER MIAMI FL
205 PM EDT TUE OCT 09 2012

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.

...TROPICAL WAVES...

AN ATLANTIC OCEAN TROPICAL WAVE IS ALONG 45W/46W TO THE SOUTH
OF 18N. A 1008 MB LOW PRESSURE CENTER IS NEAR 9N ALONG THE WAVE.
SCATTERED TO NUMEROUS STRONG CONVECTIVE PRECIPITATION IS IN
THE MONSOON TROUGH FROM 9N TO 13N BETWEEN 42W AND 51W.
ANY DEVELOPMENT OF THIS SYSTEM DURING THE NEXT COUPLE OF DAYS...
FOR THE PURPOSES OF CONSIDERING A TROPICAL CYCLONE...SHOULD
BE SLOW TO OCCUR DUE TO MARGINALLY FAVORABLE ENVIRONMENTAL
CONDITIONS. THIS SYSTEM HAS A LOW CHANCE OF BECOMING A TROPICAL
CYCLONE DURING THE NEXT 48 HOURS AS IT MOVES WEST-NORTHWESTWARD
13 TO 17 KNOTS.

...THE ITCZ/THE MONSOON TROUGH...

THE MONSOON TROUGH PASSES THROUGH COASTAL GUINEA NEAR 11N15W
9N23W 7N30W TO THE 1008 MB LOW PRESSURE THAT IS ALONG THE
45W/46W TROPICAL WAVE. THE ITCZ CONTINUES FROM THE 1008 MB LOW
PRESSURE CENTER THAT IS ALONG THE 45W/46W TROPICAL WAVE...TO
NORTHERN COASTAL FRENCH GUIANA AND ITS BORDER WITH SURINAME THAT
IS NEAR 5N ALONG 54W/55W. CONVECTIVE PRECIPITATION...SCATTERED
MODERATE TO ISOLATED STRONG IS ELSEWHERE FROM 9N TO 11N BETWEEN
50W AND 60W...WIDELY SCATTERED MODERATE TO ISOLATED STRONG
FROM 3N TO 11N TO THE EAST OF 42W.

...DISCUSSION...

THE GULF OF MEXICO...

THE BROAD BASE OF A DEEP LAYER TROUGH...THAT ORIGINATES IN THE
CENTRAL U.S.A...REACHES THE GULF OF MEXICO TO THE NORTH OF 26N.
MIDDLE LEVEL TO UPPER LEVEL WESTERLY WIND FLOW COVERS THE AREA
TO THE NORTH OF 26N. COMPARATIVELY DRIER AIR IN SUBSIDENCE IS
TO THE NORTH OF 26N. UPPER LEVEL SOUTHWESTERLY WIND FLOW COVERS
THE GULF OF MEXICO TO THE SOUTH OF 26N. A COMPARATIVELY WEAK AND
SLOWLY-MOVING COLD FRONT PASSES THROUGH 32N77W IN THE ATLANTIC
OCEAN...TO 29N82W IN FLORIDA...TO 25N90W IN THE CENTRAL GULF
WATERS...CURVING TO 23N95W AND 20N96W IN THE SOUTHWESTERN CORNER
OF THE AREA. THIS FRONT HAS BEEN MOVING SOUTHWARD SLOWLY WITH
TIME. CONVECTIVE PRECIPITATION...ISOLATED MODERATE TO THE
SOUTHEAST OF 25N81W 23N88W...ISOLATED MODERATE TO THE SOUTH
OF 26N TO THE WEST OF 90W.

FROM THE ATLANTIC OCEAN INTO THE CARIBBEAN SEA...

AN UPPER LEVEL TROUGH PASSES THROUGH 33N33W TO 25N39W 25N40W AND
23N50W. THIS TROUGH IS COMING INTO PHASE SOMEWHAT WITH THE
TROUGH THAT RUNS FROM 23N50W TO THE 21N55W MIDDLE LEVEL TO UPPER
LEVEL CYCLONIC CIRCULATION CENTER THAT WE HAVE BEEN FOLLOWING
FOR AT LEAST THE LAST WEEK...AS THAT CYCLONIC CENTER HAS BEEN
MOVING WESTWARD STEADILY WITH TIME. ONE TROUGH EXTENDS FROM THE
CENTER TO 20N67W. A SECOND TROUGH EXTENDS FROM THE CENTER TO
14N58W. UPPER LEVEL NORTHERLY WIND FLOW COVERS THE CARIBBEAN SEA
TO THE NORTH OF 13N TO THE EAST OF 70W. THE 33N33W TO 25N40W
PART OF THE TROUGH WAS SUPPORTING AN EASTERN ATLANTIC OCEAN COLD
FRONT DURING THE LAST THREE TO FOUR DAYS. THE FRONT NO LONGER IS
PART OF THE SURFACE MAP ANALYSIS. A REMNANT CLOUD
LINE...CONSISTING OF BROKEN TO OVERCAST MULTILAYERED CLOUDS AND
RAINSHOWERS AND POSSIBLE THUNDERSTORMS...IS WITHIN 60 TO 90 NM
ON EITHER SIDE OF THE LINE THAT PASSES THROUGH 32N22W 27N30W
24N40W 22N51W 19N55W 18N59W. BROAD SURFACE ANTICYCLONIC WIND
FLOW IS TO THE NORTH OF 20N BETWEEN AFRICA AND 70W.

THE NORTHEASTERLY WIND FLOW THAT IS IN THE CARIBBEAN SEA TO THE
NORTH OF 13N BETWEEN 65W AND 70W EVENTUALLY FEEDS INTO THE
CYCLONIC WIND FLOW THAT IS MOVING AROUND AN UPPER LEVEL CYCLONIC
CIRCULATION CENTER THAT IS NEAR 14N72W. CYCLONIC WIND FLOW
AROUND THIS CENTER COVERS THE AREA BETWEEN 65W AND 76W. ISOLATED
MODERATE CONVECTIVE PRECIPITATION IS ELSEWHERE TO THE EAST OF
76W.

THE REST OF THE CARIBBEAN SEA...

THE SOUTHWESTERN CORNER OF THE AREA HAS BEEN AN AREA OF BROAD
SURFACE LOW PRESSURE AND CONVECTIVE PRECIPITATION FOR THE LAST
24 HOURS OR SO. THE MONSOON TROUGH CURRENTLY PASSES THROUGH
EXTREME NORTHWESTERN VENEZUELA...IN THE AREA BETWEEN LAKE
MARACAIBO AND THE VENEZUELA/COLOMBIA BORDER...TO 11N80W...
WESTWARD THROUGH NORTHWESTERN COSTA RICA. A SURFACE LOW PRESSURE
CENTER WAS INCLUDED IN THE SURFACE MAP ANALYSIS OF 08/1200 UTC.
CONVECTIVE PRECIPITATION...SCATTERED TO NUMEROUS STRONG
CONVECTIVE PRECIPITATION FROM 11N TO 17N BETWEEN 77W AND 80W...
SCATTERED MODERATE TO ISOLATED STRONG FROM THE COSTA RICA/
NICARAGUA BORDER TO 18N BETWEEN 80W AND 84W...AND IN THE
EASTERN PACIFIC OCEAN TO THE NORTH OF 5N TO THE EAST OF 83W.

THE REST OF THE ATLANTIC OCEAN...

A SURFACE TROUGH IS ALONG 74W/75W FROM 23N TO 31N.
A 1013 MB LOW PRESSURE CENTER IS NEAR 23N ALONG THE TROUGH.
SCATTERED TO NUMEROUS STRONG CONVECTIVE PRECIPITATION IS
WITHIN 90 NM ON EITHER SIDE OF THE LINE THAT PASSES THROUGH
32N70W 28N71W 22N73W NEAR THE SOUTHEASTERN BAHAMAS.

PLEASE REFER TO THE ATLANTIC HIGH SEAS FORECAST...MIAHSFAT2...
FOR MORE DETAILS ABOUT 20 KNOT WINDS AND 8 TO 10 FOOT
SEA HEIGHTS TO BE RELATED TO A 1008 MB LOW PRESSURE CENTER
NEAR 09N45W AT THE START...NEAR 1010 MB 11N54W AT 24 HOURS...
AND LOW PRESSURE DISSIPATED AT 48 HOURS. A TROPICAL WAVE WILL
CONTINUE ALONG 55W TO THE SOUTH OF 17N AT 48 HOURS.

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

$$
MT





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