Tropical Weather Discussion
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000
AXNT20 KNHC 280002
TWDAT

TROPICAL WEATHER DISCUSSION
NWS NATIONAL HURRICANE CENTER MIAMI FL
805 PM EDT MON OCT 27 2014

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 1800 UTC SURFACE ANALYSIS AND SATELLITE IMAGERY THROUGH
2315 UTC.

...SPECIAL FEATURES...

THE CENTER OF TROPICAL STORM HANNA AT 28/0000 UTC IS NEAR 14.6N
82.4W. THE CENTER OF HANNA IS INLAND IN EXTREME NORTHEASTERN
NICARAGUA. THE CENTER IS ABOUT 60 NM TO THE WEST-SOUTHWEST OF
CABO GRACIAS A DIOS...THAT IS ON THE BORDER OF NICARAGUA AND
HONDURAS...AND ALSO ABOUT 60 NM TO THE NORTHWEST OF PUERTO
CABEZAS IN NICARAGUA. THE STORM IS MOVING WESTWARD OR 265
DEGREES 6 KNOTS. THE ESTIMATED MINIMUM CENTRAL PRESSURE IS 1006
MB. THE MAXIMUM SUSTAINED WIND SPEEDS ARE 35 KNOTS WITH GUSTS TO
45 KNOTS. HANNA IS FORECAST TO TURN WEST-SOUTHWESTWARD TONIGHT.
HANNA WILL CONTINUE TO MOVE MORE INLAND IN NORTHERN NICARAGUA.
PUBLIC ADVISORIES ON TROPICAL STORM HANNA ARE ISSUED UNDER WMO
HEADER WTNT34 KNHC AND UNDER AWIPS HEADER MIATCPAT4. FORECAST/
ADVISORIES ON TROPICAL STORM HANNA ARE ISSUED UNDER WMO HEADER
WTNT24 KNHC AND UNDER AWIPS HEADER MIATCMAT4. CONVECTIVE
PRECIPITATION...SCATTERED TO NUMEROUS STRONG FROM 14N TO 19N
BETWEEN 82W AND 85W...FROM NORTHEASTERN NICARAGUA...ACROSS
EASTERN HONDURAS...INTO THE NORTHWESTERN CORNER OF THE CARIBBEAN
SEA.

...TROPICAL WAVES...

AN ATLANTIC OCEAN TROPICAL WAVE IS ALONG 22W/23W FROM 17N
SOUTHWARD...MOVING WESTWARD 10 TO 15 KNOTS. CONVECTIVE
PRECIPITATION...ISOLATED MODERATE FROM 10N TO 17N
BETWEEN 21W AND 23W.

AN ATLANTIC OCEAN TROPICAL WAVE IS ALONG 58W/59W FROM 20N
SOUTHWARD. THE WAVE IS MOVING WESTWARD 15 KNOTS. CONVECTIVE
PRECIPITATION...SCATTERED STRONG FROM 10N TO 14N BETWEEN 56W AND
60W...AND FROM 14N TO 18N BETWEEN 53W AND 57W. WIDELY SCATTERED
MODERATE TO ISOLATED STRONG ELSEWHERE FROM 10N TO 21N BETWEEN
50W AND 60W.

AN EASTERN CARIBBEAN SEA TROPICAL WAVE IS ALONG 64W/65W FROM 18N
SOUTHWARD. THE WAVE IS MOVING WESTWARD 10 TO 15 KNOTS.
CONVECTIVE PRECIPITATION...WIDELY SCATTERED TO SCATTERED
MODERATE AND ISOLATED STRONG FROM 10N TO 18N BETWEEN 60W AND
65W.

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

THE MONSOON TROUGH PASSES THROUGH THE COASTAL SECTIONS OF GUINEA
NEAR 11N15W TO 9N20W. THE ITCZ CONTINUES FROM 9N20W TO 9N33W
7N45W AND 8N56W. CONVECTIVE PRECIPITATION...NUMEROUS STRONG FROM
5N TO 10N BETWEEN 30W AND 43W. NUMEROUS STRONG FROM 8N TO 10N
BETWEEN 11W AND 14W MOSTLY IN SIERRA LEONE. WIDELY SCATTERED
MODERATE TO ISOLATED STRONG FROM 4N TO 10N BETWEEN 20W AND 30W.

...DISCUSSION...

...THE GULF OF MEXICO...

MIDDLE LEVEL TO UPPER LEVEL ANTICYCLONIC WIND FLOW COVERS THE
GULF OF MEXICO. A RIDGE IS ALONG 88W. COMPARATIVELY DRIER AIR IN
SUBSIDENCE IS APPARENT IN WATER VAPOR IMAGERY...ACROSS MUCH OF
THE AREA. HIGH LEVEL MOISTURE HAS WORKED ITS WAY INTO THE GULF
OF MEXICO FROM INTERIOR SECTIONS OF MEXICO...WITHIN 90 NM ON
EITHER SIDE OF 18N103W 21N98W 25N90W.

A SURFACE RIDGE EXTENDS FROM A 1019 MB ATLANTIC OCEAN HIGH
PRESSURE CENTER THAT IS NEAR 30N80W...ACROSS NORTHEASTERN
FLORIDA...INTO THE NORTHWESTERN CORNER OF THE GULF OF MEXICO
NEAR 27N93W...AND TO THE NORTHEASTERN COASTAL AREAS OF MEXICO.

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

LOW LEVEL CLOUD CEILINGS ARE BEING REPORTED AT...KGVX...KXIH...
KEMK...AND KGHB.

LOW CLOUD CEILINGS AND WEATHER...FOR THE COASTAL PLAINS OF THE
U.S.A. FROM THE DEEP SOUTH OF TEXAS TO FLORIDA...

SCATTERED TO BROKEN LOW LEVEL CLOUDS ARE IN PARTS OF THE MIDDLE
TEXAS GULF COASTAL PLAINS. SCATTERED TO BROKEN LOW LEVEL CLOUDS
COVER PARTS OF TEXAS FROM THE MIDDLE TEXAS COASTAL PLAINS TO AND
INCLUDING THE HOUSTON METROPOLITAN AREA. LIGHT RAIN IS BEING
OBSERVED IN GALVESTON TEXAS. A LOW LEVEL CLOUD CEILING IS BEING
REPORTED AT THE PENSACOLA INTERNATIONAL AIRPORT.

...THE CARIBBEAN SEA...

TROPICAL STORM HANNA IS THE MAIN WEATHER FEATURE FOR THE
CARIBBEAN SEA AREA AT THIS MOMENT. IT IS INLAND IN NORTHEASTERN
NICARAGUA. PLEASE READ THE SPECIAL FEATURE SECTION FOR MORE
DETAILS ABOUT TROPICAL STORM HANNA.

BROAD MIDDLE LEVEL TO UPPER LEVEL ANTICYCLONIC WIND FLOW COVERS
THE CARIBBEAN SEA BETWEEN 70W AND 80W.

A MIDDLE LEVEL TO UPPER LEVEL TROUGH IS ALONG 23N60W 19N63W...
TO A CYCLONIC CIRCULATION CENTER THAT IS NEAR 14N65W IN THE
EASTERN CARIBBEAN SEA. THE TROUGH CONTINUES TO THE COAST OF
VENEZUELA NEAR 10N67W. THE 58W/59W TROPICAL WAVE AND THE 64W/65W
TROPICAL WAVE ARE MOVING THROUGH THE AREA OF THIS TROUGH.
CONVECTIVE PRECIPITATION...IT IS NOT EASY TO KNOW WHICH
PRECIPITATION IS JUST RELATED TO THE TROPICAL WAVES AND WHICH IS
JUST RELATED TO THE TROUGH. SCATTERED STRONG FROM 10N TO 14N
BETWEEN 56W AND 60W...AND FROM 14N TO 18N BETWEEN 53W AND 57W.
WIDELY SCATTERED MODERATE TO ISOLATED STRONG ELSEWHERE FROM 10N
TO 21N BETWEEN 50W AND 60W. WIDELY SCATTERED TO SCATTERED
MODERATE AND ISOLATED STRONG FROM 10N TO 18N BETWEEN 60W AND
65W. SCATTERED STRONG IN NORTHWESTERN VENEZUELA FROM 9N TO 10N
BETWEEN 67W AND 70W.

THE MONSOON TROUGH IS ALONG 11N75W ALONG THE COAST OF
COLOMBIA...TO 9N80W ON THE CARIBBEAN SEA SIDE OF PANAMA...BEYOND
SOUTHERN COSTA RICA...INTO THE EASTERN PACIFIC OCEAN. CONVECTIVE
PRECIPITATION...SCATTERED STRONG FROM 10N TO 12N BETWEEN 81W AND
82W.

...HISPANIOLA...

THE BASE OF A MIDDLE LEVEL TO UPPER LEVEL TROUGH REACHES
SOUTHEASTERN CUBA NEAR 21N76W. UPPER LEVEL WESTERLY TO
NORTHWESTERLY WIND FLOW CROSSES HISPANIOLA. CONVECTIVE
PRECIPITATION...SCATTERED TO NUMEROUS STRONG BETWEEN 69W AND
70W...AND ALONG THE SOUTHERN BORDER OF HAITI AND THE DOMINICAN
REPUBLIC.

CLOUD CONDITIONS/PREVAILING WEATHER FOR THE DOMINICAN
REPUBLIC...FEW CUMULONIMBUS CLOUDS AND A LOW LEVEL CLOUD CEILING
AT A DIFFERENT LEVEL ARE BEING REPORTED IN BARAHONA...IN PUNTA
CANA...AND IN SANTIAGO. RAINSHOWERS WITH THUNDER AND
MULTILAYERED CLOUD LAYERS ARE BEING REPORTED IN SANTO DOMINGO IN
LA ROMANA...AND IN PUERTO PLATA.

THE GFS MODEL FORECAST FOR 250 MB SHOWS THAT NORTHWEST-TO-
SOUTHEAST ORIENTED TROUGH WILL COVER HISPANIOLA FOR THE FIRST 30
HOURS OR SO OF THE 48 HOUR FORECAST PERIOD. THE TROUGH WILL MOVE
EASTWARD AND EVENTUALLY COVER PUERTO RICO. HISPANIOLA WILL BE ON
THE WESTERN SIDE OF THE TROUGH. THE GFS MODEL FOR 500 MB SHOWS
THAT A RIDGE WILL COVER HISPANIOLA FOR THE NEXT 48 HOURS OR SO.
THE GFS MODEL FORECAST FOR 700 MB SHOWS THAT A NORTHEAST-TO-
SOUTHWEST ORIENTED RIDGE WILL CROSS HISPANIOLA FOR THE FIRST 24
HOURS OF THE 48 HOUR FORECAST PERIOD. THE RIDGE WILL BREAK DOWN
AND IT WILL LEAD TO NORTHEASTERLY-TO-EASTERLY WIND FOR THE
SECOND SET OF 24 HOURS.

...THE ATLANTIC OCEAN...

A MIDDLE LEVEL TO UPPER LEVEL TROUGH PASSES THROUGH 32N64W...
JUST TO THE EAST OF BERMUDA...TO 28N66W...BECOMING A SHEAR AXIS
FROM 28N66W TO 23N72W. A SECOND MIDDLE LEVEL TO UPPER LEVEL
TROUGH IS ABOUT 240 NM TO THE EAST OF THE BERMUDA-TO-23N72W
TROUGH/SHEAR AXIS. A FIRST COLD FRONT PASSES THROUGH 32N53W TO
29N58W AND 26N63W. A STATIONARY FRONT CONTINUES FROM 26N63W TO
23N66W...TO 20N70W...CUTTING ACROSS THE NORTHWESTERN CORNER OF
THE DOMINICAN REPUBLIC...AND SOUTHWESTWARD ACROSS HAITI.
A SECOND COLD FRONT PASSES THROUGH 32N58W TO 29N66W AND 28N73W.
CONVECTIVE PRECIPITATION...WIDELY SCATTERED MODERATE TO ISOLATED
STRONG WITHIN 60 NM ON EITHER SIDE OF 26N62W 20N67W.

A SURFACE RIDGE PASSES THROUGH 32N23W...TO A 1022 MB HIGH
PRESSURE CENTER THAT IS NEAR 29N39W...TO 27N46W AND TO 23N62W.

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

$$
MT



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