[Tropical] Tropical Weather Discussion

[EMWIN Server]

AXNT20 KNHC 191208
TWDAT

TROPICAL WEATHER DISCUSSION
NWS TPC/NATIONAL HURRICANE CENTER MIAMI FL
705 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 0600 UTC SURFACE ANALYSIS AND SATELLITE IMAGERY
THROUGH 1145 UTC

...THE ITCZ...
FROM 10N14W TO 4N20W TO 1N30W 1N40W...CROSSING THE EQUATOR AT
42W...STAYING JUST SOUTH OF THE EQUATOR AND CONTINUING INTO
NORTHEASTERN BRAZIL NEAR 1S50W. SCATTERED MODERATE TO STRONG
SHOWERS/THUNDERSTORMS IN INDIVIDUAL CLUSTERS FROM THE EQUATOR
TO 7N EAST OF 45W.

...DISCUSSION...

THE GULF OF MEXICO...
A MIDDLE TO UPPER LEVEL SHORTWAVE TROUGH EXTENDS FROM EAST
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
30N77W TO LAKE OKEECHOBEE IN FLORIDA...TO THE CENTRAL GULF OF
MEXICO...TO A 1008 MB GALE LOW PRESSURE CENTER NEAR 26N95W.
A COLD FRONT EXTENDS FROM THE LOW CENTER SOUTHWARD TO 22N95W.
A STATIONARY FRONT CONTINUES FROM 22N95W TO 19N96W...CURVING
NORTHWESTWARD INTO MEXICO NEAR 25N103W AND 29N109W. SCATTERED
MODERATE SHOWERS TO ISOLATED STRONG THUNDERSTORMS FROM 26N TO
LOUISIANA BETWEEN 90W AND 92W...AND FROM 27N TO FLORIDA BETWEEN
83W AND 87W.

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 11N60W
14N70W 15N83W 15N84W IN SURFACE WESTERLY WIND FLOW. SHOWERS
ARE OFF THE NORTHEASTERN COAST OF THE YUCATAN PENINSULA.

THE ATLANTIC OCEAN...
A WESTERN ATLANTIC STATIONARY FRONT PASSES THROUGH 32N70W TO
30N77W TO LAKE OKEECHOBEE. A WARM FRONT CONTINUES FROM LAKE
OKEECHOBEE FLORIDA INTO THE CENTRAL GULF OF MEXICO. ISOLATED
MODERATE SHOWERS ARE NORTH OF 30N BEYOND 32N BETWEEN 60W AND THE
SOUTHEASTERN U.S.A. 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 32N31W
TO 26N36W TO 22N43W...BECOMING STATIONARY AT 22N43W AND
CONTINUING TO 20N50W AND 20N59W. A MIDDLE TO UPPER LEVEL TROUGH
THAT 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
400 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 15N40W
TO THE CANARY ISLANDS TO THE MADEIRA ISLANDS

$$
MT




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