[Tropical] Tropical Weather Discussion

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AXNT20 KNHC 171805
TWDAT

TROPICAL WEATHER DISCUSSION
NWS NATIONAL HURRICANE CENTER MIAMI FL
205 PM EDT TUE SEP 17 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 FEATURES...

THE CENTER OF TROPICAL STORM HUMBERTO AT 17/1500 UTC IS NEAR
29.4N 42.5W. HUMBERTO IS MOVING NORTHWARD 9 KNOTS. THE ESTIMATED
MINIMUM CENTRAL PRESSURE IS 1007 MB. THE MAXIMUM SUSTAINED WIND
SPEEDS ARE 40 KNOTS WITH GUSTS TO 50 KNOTS. PLEASE READ THE
PUBLIC ADVISORIES ABOUT HUMBERTO THAT ARE ISSUED UNDER WMO
HEADER WTNT34 KNHC AND UNDER AWIPS HEADER MIATCPAT4...AND THE
FORECAST/ADVISORIES THAT ARE ISSUED UNDER WMO HEADER WTNT24 KNHC
AND UNDER AWIPS HEADER MIATCMAT4. CONVECTIVE PRECIPITATION...
SCATTERED STRONG WAS FROM 27N TO 30N BETWEEN 40W AND 42W.
SCATTERED MODERATE TO STRONG IS ELSEWHERE FROM 28N TO 33N
BETWEEN 40W AND 45W.

A SURFACE TROUGH IS ALONG THE COAST OF THE NORTHWESTERN CORNER
OF THE CARIBBEAN SEA...FROM THE YUCATAN PENINSULA...THROUGH THE
GULF OF HONDURAS...INTO EL SALVADOR. A 1007 MB LOW PRESSURE
CENTER IS ALONG THE TROUGH NEAR 18N88W. CONVECTIVE
PRECIPITATION...SCATTERED TO NUMEROUS STRONG FROM HONDURAS AND
GUATEMALA ALONG 15N TO 19N IN THE YUCATAN PENINSULA BETWEEN 86W
AND 89W. NUMEROUS STRONG ALSO IN THE NORTHWESTERN CARIBBEAN SEA
FROM 18N TO 20N BETWEEN 79W AND 84W. SCATTERED STRONG IS
DEVELOPING FROM 14N TO 15N BETWEEN 81W AND 82W. THIS SYSTEM IS
FORECAST TO MOVE SLOWLY TOWARD THE WEST-NORTHWEST AND EMERGE
OVER THE BAY OF CAMPECHE ON WEDNESDAY. SURFACE PRESSURES ARE LOW
IN THIS AREA...AND ENVIRONMENTAL CONDITIONS ARE EXPECTED TO BE
FAVORABLE FOR DEVELOPMENT DURING THE NEXT DAY OR TWO. THIS LOW
HAS A MEDIUM CHANCE OF BECOMING A TROPICAL CYCLONE DURING THE
NEXT 48 HOURS. ENVIRONMENTAL CONDITIONS SHOULD CONTINUE TO BE
GENERALLY CONDUCIVE FOR SOME ADDITIONAL DEVELOPMENT DURING THE
NEXT SEVERAL DAYS AS THE DISTURBANCE MOVES SLOWLY ACROSS THE
SOUTHERN GULF OF MEXICO. THIS SYSTEM HAS A HIGH CHANCE OF
BECOMING A TROPICAL CYCLONE DURING THE NEXT 5 DAYS. THIS
DISTURBANCE WILL LIKELY SPREAD HEAVY RAINS OVER EASTERN MEXICO.
THESE RAINS MAY CAUSE LIFE-THREATENING FLOODS AND MUD SLIDES IN
AREAS THAT ALREADY HAVE BEEN IMPACTED BY THE TORRENTIAL RAINS
THAT HAVE BEEN ASSOCIATED WITH INGRID AND MANUEL...REGARDLESS OF
TROPICAL CYCLONE FORMATION. THE 24-HOUR RAINFALL TOTAL IN INCHES
FOR THE PERIOD ENDING AT 17/1200 UTC...ACCORDING TO THE PAN
AMERICAN TEMPERATURE AND PRECIPITATION TABLES...MIATPTPAN...IS
0.07 IN MERIDA IN MEXICO.

...TROPICAL WAVES...

A TROPICAL WAVE IS ALONG 22N22W...TO 16N25W IN THE WESTERN CAPE
VERDE ISLANDS...TO 10N27W. THE WAVE IS MOVING WESTWARD 10 TO 15
KNOTS. CONVECTIVE PRECIPITATION...SCATTERED MODERATE TO ISOLATED
STRONG FROM 16N TO 20N BETWEEN 18W AND 24W.

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

THE MONSOON TROUGH PASSES THROUGH COASTAL SENEGAL NEAR 14N17W TO
14N22W 11N29W 10N33W. THE ITCZ CONTINUES FROM 10N33W TO 11N40W
TO 11N51W. CONVECTIVE PRECIPITATION...NUMEROUS STRONG FROM 12N
TO 13N BETWEEN 57W AND 61W. SCATTERED MODERATE TO ISOLATED
STRONG FROM 7N TO 9N BETWEEN 14W AND 18W...FROM 7N TO 10N
BETWEEN 25W AND 34W...FROM 6N TO 15N BETWEEN 39W AND 50W...AND
FROM 10N TO 12N BETWEEN 48W AND 54W.

...DISCUSSION...

FROM THE U.S.A. COASTAL WATERS OF THE ATLANTIC OCEAN...ACROSS
FLORIDA...INTO THE EASTERN GULF OF MEXICO...

A MIDDLE LEVEL TO UPPER LEVEL TROUGH PASSES THROUGH 32N78W TO
29N82W IN FLORIDA...TO 27N84W...TO A 23N86W EASTERN GULF OF
MEXICO CYCLONIC CIRCULATION CENTER. THE TROUGH SUPPORTS A COLD
FRONT THAT PASSES THROUGH 32N74W TO SOUTHEASTERN GEORGIA...INTO
THE FLORIDA PANHANDLE...AND BEYOND SOUTHEASTERN LOUISIANA.
CONVECTIVE PRECIPITATION...SCATTERED MODERATE TO ISOLATED STRONG
IN THE GULF OF MEXICO AND FLORIDA...AND IN THE ATLANTIC OCEAN
ENCOMPASSING THE BAHAMAS...FROM THE COAST OF CUBA TO LAKE
OKEECHOBEE IN SOUTHEASTERN FLORIDA BETWEEN 75W AND 85W.
SCATTERED STRONG FROM 28N TO 30N BETWEEN 73W AND 76W. ISOLATED
MODERATE ELSEWHERE TO THE NORTH OF 20N AND CUBA...ACROSS THE
BAHAMAS TO THE WEST OF 70W. SCATTERED MODERATE TO ISOLATED
STRONG IN THE ATLANTIC OCEAN WITHIN 30 NM TO 45 NM ON EITHER
SIDE OF THE LINE THAT PASSES THROUGH 32N73W TO 31N81W. THE 24-
HOUR RAINFALL TOTAL IN INCHES FOR THE PERIOD ENDING AT 16/1200
UTC...ACCORDING TO THE PAN AMERICAN TEMPERATURE AND
PRECIPITATION TABLES...MIATPTPAN...0.18 IN FREEPORT IN THE
BAHAMAS...AND 0.09 IN BERMUDA.

THE REST OF THE GULF OF MEXICO...

A SURFACE TROUGH IS INLAND...WITHIN 50 NM TO 75 NM TO THE WEST
OF THE MEXICO COAST ON THE GULF OF MEXICO SIDE. THE TROUGH
REPRESENTS THE REMNANTS OF INGRID. CONVECTIVE PRECIPITATION...
NUMEROUS STRONG WITHIN 60 NM TO 120 NM OF THE GULF OF MEXICO
COAST FROM 18N TO 24N.

FOR THE OFFSHORE OIL PLATFORM SITES THAT ARE TO THE NORTH
OF 27N TO THE WEST OF 88W...

BROKEN LOW CLOUDS ARE BEING REPORTED AT THE ICAO STATIONS KSPR
AND KGVX...AND BROKEN MIDDLE LEVEL CLOUDS ARE BEING REPORTED AT
THE ICAO STATIONS KMYT AND KMDJ. FAIR SKIES/CLEAR SKIES AT OR
LOWER THAN 12000 FEET ARE BEING REPORTED ELSEWHERE ACROSS THE
AREA.

BROKEN LOW CLOUDS AND LIGHT RAIN ARE REPORTED IN THE WESTERN/
COMPARATIVELY MORE INLAND STATIONS OF THE LOWER RIO GRANDE
VALLEY OF TEXAS. SCATTERED TO BROKEN LOW CLOUDS COVER THE
STATIONS THAT ARE COMPARATIVELY CLOSER TO THE COAST IN THE SAME
DEEP SOUTH OF TEXAS. MULTILAYERED CLOUD CEILINGS AND RAIN ARE
OBSERVED IN THE MIDDLE TEXAS GULF COASTAL PLAINS. LOW CLOUD
CEILINGS AND HIGH CLOUD CEILINGS ARE REPORTED FROM THE HOUSTON
METROPOLITAN AREA TOWARD THE SOUTH AND SOUTHWEST. A HIGH CLOUD
CEILING IS BEING REPORTED AT THE NEW ORLEANS NAVAL AIR STATION
AND AT THE NAVAL AIR STATION NEAR MILTON FLORIDA. BROKEN LOW
CLOUDS ARE OBSERVED IN TALLAHASSEE. MULTILAYERED CLOUD CEILINGS
AND RAIN AND THUNDER ARE BEING OBSERVED ALONG THE SOUTHWESTERN
COAST OF FLORIDA FROM PUNTA GORDA TO THE FLORIDA KEYS.

PLEASE READ THE HIGH SEAS FORECAST...MIAHSFAT2...AND THE
OFFSHORE FORECAST...MIAOFFNT4...FOR MORE DETAILS ABOUT EAST
WINDS 20 TO 25 KNOTS AND SEA HEIGHTS LOWER THAN 8 FEET FROM 19N
TO 24N BETWEEN 87W AND 90W.

HISPANIOLA AND PARTS OF THE CARIBBEAN SEA...

A MIDDLE LEVEL TO UPPER LEVEL TROUGH EXTENDS FROM 26N66W IN THE
ATLANTIC OCEAN...TO A 22N67W CYCLONIC CIRCULATION
CENTER...ACROSS THE DOMINICAN REPUBLIC...INTO THE CARIBBEAN SEA
NEAR 15N71W...TO THE COAST OF COLOMBIA NEAR 12N73W. CONVECTIVE
PRECIPITATION...NUMEROUS STRONG IN THE ATLANTIC OCEAN FROM 26N
TO 30N BETWEEN 65W AND 70W. ISOLATED TO WIDELY SCATTERED
MODERATE AND ISOLATED STRONG FROM THE ATLANTIC OCEAN INTO THE
CARIBBEAN SEA TO THE SOUTH OF 24N BETWEEN 62W AND 70W.

THE GFS FORECAST FOR 700 MB SHOWS THAT A RIDGE WILL COVER THE
AREA FOR THE FIRST 36 HOURS OF THE FORECAST PERIOD. AN INVERTED
TROUGH WILL COVER THE AREA FOR THE REST OF THE TIME. THE GFS
FORECAST FOR 500 MB SHOWS THAT SOUTHERLY AND SOUTHWESTERLY WIND
FLOW...FROM THE PERIPHERY OF A 17N62W ANTICYCLONIC CIRCULATION
CENTER...FOR ABOUT THE FIRST 36 HOURS OF THE FORECAST PERIOD.
THE 17N62W ANTICYCLONIC CENTER EVENTUALLY IS FORECAST TO END UP
ON TOP OF HISPANIOLA. THE GFS FORECAST FOR 250 MB SHOWS THAT THE
CURRENT TROUGH THAT ENCOMPASSES HISPANIOLA EVENTUALLY WILL SHIFT
EASTWARD BY THE END OF THE FIRST 24 HOURS...IN ORDER TO BE IN
THE MONA PASSAGE. THE TROUGH WILL SHIFT EASTWARD WITH TIME
DURING THE SECOND 24 HOUR TIME PERIOD. IT WILL PASS ON TOP OF
THE VIRGIN ISLANDS SOUTHWESTWARD.

THE REST OF THE CARIBBEAN SEA...

UPPER LEVEL ANTICYCLONIC WIND FLOW COVERS THE CARIBBEAN SEA TO
THE WEST OF 80W. BROAD SURFACE LOW PRESSURE COVERS THE
NORTHWESTERN CORNER OF THE CARIBBEAN SEA. CONVECTIVE
PRECIPITATION...NUMEROUS STRONG FROM 17N TO 20N BETWEEN 86W AND
89W COVERING THE CARIBBEAN SEA AND COASTAL PLAINS AND COASTAL
WATERS OF THE YUCATAN PENINSULA...BELIZE...AND HONDURAS...AND
FROM 20N TO THE COAST OF CUBA BETWEEN 79W AND 81W. OTHER
RAINSHOWERS ARE POSSIBLE ELSEWHERE TO THE NORTH OF 15N TO THE
WEST OF 80W. THIS AREA OF DISTURBED WEATHER IS FORECAST TO MOVE
WESTWARD OR WEST-NORTHWESTWARD ACROSS THE YUCATAN PENINSULA AND
INTO THE SOUTHWESTERN GULF OF MEXICO DURING THE NEXT FEW DAYS.
THIS SYSTEM HAS A LOW CHANCE OF BECOMING A TROPICAL CYCLONE
DURING THE NEXT 48 HOURS. ENVIRONMENTAL CONDITIONS ARE FORECAST
TO BE MARGINALLY CONDUCIVE FOR SLOW DEVELOPMENT AFTER THE FIRST
48 HOURS...AND THIS SYSTEM HAS A LOW CHANCE OF BECOMING
A TROPICAL CYCLONE DURING THE NEXT 5 DAYS.

THE 24-HOUR RAINFALL TOTALS IN INCHES FOR THE PERIOD ENDING AT
17/1200 UTC...ACCORDING TO THE PAN AMERICAN TEMPERATURE AND
PRECIPITATION TABLES...MIATPTPAN...ARE 0.72 IN TRINIDAD...0.42
IN GUADELOUPE...AND 0.22 IN MONTEGO BAY IN JAMAICA.

PLEASE READ THE HIGHS SEAS FORECAST...MIAHSFAT2...AND THE
OFFSHORE FORECAST...MIAOFFNT3...FOR MORE DETAILS ABOUT EAST TO
SOUTHEAST WINDS 20 TO 30 KNOTS AND SEA HEIGHTS TO 8 FEET TO THE
NORTH OF 17N TO THE WEST OF 83W. EXPECT ALSO EAST WINDS 20 KNOTS
OR LESS AND SEA HEIGHTS TO 9 FEET FROM 12N TO 17N BETWEEN
68W AND 77W.

THE REST OF THE ATLANTIC OCEAN...

A SURFACE TROUGH IS ALONG 29N69W...TO A 1015 MB LOW PRESSURE
CENTER THAT IS NEAR 27N71W...TO 23N71W. THIS TROUGH IS PART OF
THE REMNANT OF THE 1009 MB LOW PRESSURE CENTER THAT WAS NEAR
24N63W ABOUT 48 HOURS AGO. UPPER LEVEL WIND NORTHERLY WIND FLOW
MOVING ON TOP OF THIS FEATURE...RELATED TO THE WIND FLOW THAT IS
MOVING AROUND THE 22N67W CYCLONIC CIRCULATION CENTER. CONVECTIVE
PRECIPITATION...SCATTERED MODERATE FROM 25N TO 27N BETWEEN 65W
AND 71W.

A 1018 MB HIGH PRESSURE CENTER IS NEAR 30N55W. AN EASTERN
ATLANTIC OCEAN SURFACE RIDGE IS ALONG 28W FROM 25N BEYOND 32N. A
1031 MB HIGH PRESSURE CENTER IS NEAR 41N28W.

PLEASE READ THE HIGH SEAS FORECAST...MIAHSFAT2...FOR MORE
DETAILS ABOUT TROPICAL STORM HUMBERTO.

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

$$
MT


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