[Tropical] Tropical Weather Discussion

[EMWIN Server]

AXNT20 KNHC 190604
TWDAT

TROPICAL WEATHER DISCUSSION
NWS TPC/NATIONAL HURRICANE CENTER MIAMI FL
105 AM EST SAT JAN 19 2008

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 0000 UTC SURFACE ANALYSIS AND SATELLITE IMAGERY
THROUGH 0515 UTC

...THE ITCZ...
FROM 10N14W TO 4N20W TO 1N30W 1N40W...CROSSING THE EQUATOR AT
45W...STAYING JUST SOUTH OF THE EQUATOR AND CONTINUING INTO
NORTHEASTERN BRAZIL NEAR 1S50W. SCATTERED MODERATE TO STRONG
SHOWERS/THUNDERSTORMS IN CLUSTERS FROM THE EQUATOR TO 2N BETWEEN
THE PRIME MERIDIAN AND 5W...FROM 3N TO 6N BETWEEN 13W AND 15W...
FROM 3N TO 5N BETWEEN 25W AND 30W...FROM THE EQUATOR TO 5N
BETWEEN 31W AND 38W...AND FROM 1N TO 2N BETWEEN 42W AND 43W.
SHOWERS ARE POSSIBLE SOUTH OF 10N ELSEWHERE WEST OF 40W...
AND FROM 10N TO 18N BETWEEN 30W AND 45W. HIGH CLOUDS ARE
STREAMING NORTHEASTWARD FROM THE AREA OF GUYANA/SURINAME/
FRENCH GUIANA ACROSS THE ATLANTIC OCEAN...WITHIN 350 NM ON
EITHER SIDE OF 5N53W 12N38W BEYOND 19N19W.

...DISCUSSION...

THE GULF OF MEXICO...
A MIDDLE TO UPPER LEVEL SHORTWAVE TROUGH EXTENDS FROM CENTRAL
TEXAS TO SOUTH CENTRAL TEXAS INTO NORTHEASTERN/NORTH CENTRAL
MEXICO. BROAD MIDDLE TO UPPER LEVEL SOUTHWESTERLY WIND FLOW
COVERS THE OPEN WATERS OF THE GULF OF MEXICO. THE FRONTAL
BOUNDARY IN THE GULF OF MEXICO LACKS STRONG SUPPORT IN THE
MIDDLE TO UPPER LEVELS OF THE ATMOSPHERE. AN ATLANTIC OCEAN
STATIONARY FRONT EXTENDS FROM 30N75W TO FLORIDA ALONG THE
SOUTHERN EDGE OF LAKE OKEECHOBEE...INTO THE SOUTHEASTERN GULF
OF MEXICO. A WARM FRONT CONTINUES FROM THE SOUTHEASTERN GULF
OF MEXICO TO THE CENTRAL GULF...TO A 1007 MB DEVELOPING GALE
LOW PRESSURE CENTER NEAR 24N95W. A STATIONARY FRONT CONTINUES
FROM THE GALE CENTER TO 20N96W...CURVING NORTHWESTWARD THROUGH
20N98W 25N102W AND 28N108W IN NORTHWESTERN MEXICO. SCATTERED
MODERATE SHOWERS TO ISOLATED STRONG THUNDERSTORMS FROM 25N TO
30N BETWEEN 87W AND 96W. SHOWERS ARE POSSIBLE ELSEWHERE
NORTHWEST OF 29N83W 23N90W 19N91W.

THE CARIBBEAN SEA...
BROAD UPPER LEVEL ANTICYCLONIC FLOW COVERS THE ATLANTIC OCEAN
SOUTH OF 32N WEST OF 55W...AND INCLUDING IN THE CARIBBEAN SEA.
A MIDDLE LEVEL ANTICYCLONIC CIRCULATION CENTER IS SUPPOSED TO BE
ABOUT 90 NM NORTH OF EASTERN HISPANIOLA ACCORDING TO THE GFS
MODEL. SUCH A CENTER IS NOT EASY TO SEE WITH THE NAKED EYE ON
SATELLITE IMAGERY. MIDDLE TO UPPER LEVEL DRY AIR/SUBSIDENCE
COVERS THE ENTIRE AREA. SURFACE EASTERLY WIND FLOW IS LOOSELY
RELATED TO LARGE SCALE ANTICYCLONIC FLOW. NO ANTICYCLONIC
CIRCULATION CENTER IS ANYWHERE NEAR THE CARIBBEAN SEA. ONE
CENTER IS ABOUT 150 NM EAST-NORTHEAST OF BERMUDA IN THE ATLANTIC
OCEAN. LARGE-SCALE ANTICYCLONIC FLOW FROM THIS ATLANTIC OCEAN
HIGH PRESSURE CENTER REACHES THE CARIBBEAN SEA. THE ISOBARS ON
THE SURFACE MAP DO NOT APPEAR TO SHOW A STRONG PRESSURE
GRADIENT. THAT DOES NOT MEAN THAT A SLIGHT CHANGE IN THE
PRESSURE FIELD IS NOT ABLE TO GENERATE COMPARATIVELY STRONGER
WIND SPEEDS ACROSS THE OPEN WATERS OF THE CARIBBEAN SEA. AN
EXAMPLE OF FAST WINDS FROM WHAT DOES NOT APPEAR TO BE SUCH
A STRONG GRADIENT ACCORDING TO THE ISOBARIC ANALYSIS IS FROM
10N TO 18N BETWEEN 70W AND 80W NORTHEAST-TO-EAST WINDS FROM
20 KT TO 30 KT AND SEAS FROM 8 TO 13 FT CURRENTLY AND IN THE
MIAHSFAT2 FORECAST FOR THE NEXT 24 TO 48 HOURS. PLEASE REFER
TO THE MIAHSFAT2 HIGH SEAS FORECAST FOR SPECIFIC DETAILS.
POSSIBLE SHOWERS IN CLUSTERS OF LOW CLOUDS ARE NORTH OF 12N60W
14N70W 15N80W 15N84W IN SURFACE WESTERLY WIND FLOW.

THE ATLANTIC OCEAN...
A WESTERN ATLANTIC COLD FRONT PASSES THROUGH 33N70W TO 30N75W.
A STATIONARY FRONT CONTINUES FROM 30N75W TO FLORIDA ALONG THE
SOUTHERN EDGE OF LAKE OKEECHOBEE INTO THE SOUTHEASTERN GULF OF
MEXICO. SHOWERS/THUNDERSTORMS FROM 29N TO 31N BETWEEN 76W AND
78W...AND FROM 30N TO 32N BETWEEN 64W AND 71W. BROAD MIDDLE TO
UPPER LEVEL ANTICYCLONIC WIND FLOW IS ON TOP OF THE AREA OF
THIS FRONT. AN ATLANTIC OCEAN COLD FRONT PASSES THROUGH THE
EAST CENTRAL SECTIONS NEAR 32N32W TO 24N40W TO 20N50W AND
20N59W. A MIDDLE TO UPPER LEVEL TROUGH CURVES THROUGH 33N41W
TO 29N36W TO 23N36W TO 17N46W SUPPORTS THIS COLD FRONT. ISOLATED
MODERATE SHOWERS AND POSSIBLE THUNDERSTORMS ARE WITHIN 90 NM
ON EITHER SIDE OF 20N60W 21N50W 24N40W BEYOND 32N32W.
A 1027 MB HIGH PRESSURE CENTER IS ABOUT 360 NM EAST
OF BERMUDA. THIS HIGH PRESSURE CENTER AND ITS ASSOCIATED
FLUCTUATIONS IN THE PRESSURE GRADIENT ARE PRODUCING 20 KT
TO 30 KT WIND SPEEDS IN THE SOUTH CENTRAL CARIBBEAN SEA...
AND IN PARTS OF THE ATLANTIC OCEAN. PLEASE REFER TO THE
MIAHSFAT2 HIGH SEAS FORECAST FOR SPECIFIC FORECAST INFORMATION.
AN ATLANTIC OCEAN MIDDLE TO UPPER LEVEL TROUGH PASSES THROUGH
30N21W TO 24N23W TO 20N27W. THE HIGH CLOUDS IN A BAND FROM
THE AREA OF GUYANA/SURINAME/FRENCH GUIANA PASSING ON TOP
OF THE ITCZ TOWARD AFRICA ARE BLOCKING THE VIEW ON SATELLITE
IMAGERY OF THE REST OF THE POSSIBLE TROUGH. A SURFACE RIDGE
IS ALONG 16N50W 23N30W BEYOND 32N20W.

$$
MT


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