[Tropical] Tropical Weather Discussion

[EMWIN Server]

AXNT20 KNHC 311824
TWDAT

TROPICAL WEATHER DISCUSSION
NWS TPC/NATIONAL HURRICANE CENTER MIAMI FL
105 PM EST WED JAN 31 2007

TROPICAL WEATHER DISCUSSION FOR NORTH AMERICA...
CENTRAL AMERICA...THE GULF OF MEXICO...THE CARIBBEAN SEA...
NORTHEASTERN 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 1200 UTC SURFACE ANALYSIS AND SATELLITE IMAGERY
THROUGH 1745 UTC.

...THE ITCZ...
6N4W 1N20W...CROSSING THE EQUATOR AT 30W...1S40W TO 1S50W IN
NORTHERN BRAZIL. 4N8W 3N18W 3N30W 3N35W. 1S21W 3S27W 2S28W
1S34W. STRONG SHOWERS AND THUNDERSTORMS FROM 3N TO 4N BETWEEN
14W AND 15W. ISOLATED MODERATE TO LOCALLY STRONG THUNDERSTORMS
ARE WITHIN 30 NM ON EITHER SIDE OF 4N8W 3N18W 3N30W 3N35W...
AND 1S21W 3S27W 2S28W 1S34W...AND FROM 1N TO 2N BETWEEN 38W
AND 39W.

...DISCUSSION...
THE GULF OF MEXICO...
THE BASE OF NORTHEAST-TO-SOUTHWEST TILT DEEP LAYER TROUGH IS
ABOUT 500 NM WEST OF THE SOUTHERN BAJA PENINSULA OF CALIFORNIA.
THE DEEPENING TROUGH IN THE EASTERN PACIFIC OCEAN HELPS TO BUILD
THE MIDDLE TO UPPER LEVEL RIDGE FROM NORTHERN MEXICO/WEST TEXAS
NORTHWARD. THE MIDDLE TO UPPER LEVEL ANTICYCLONIC FLOW THAT
COVERS MEXICO SOUTH OF 20N IS RELATED TO A MIDDLE TO UPPER LEVEL
RIDGE ORIGINATING FROM 12N102W IN THE EASTERN PACIFIC OCEAN.
CIMSS SATELLITE DERIVED WIND DATA FROM 31/1500 UTC SHOW MIDDLE
LEVEL ZONAL FLOW MOSTLY AROUND THE COASTAL PLAINS/WATERS OF THE
GULF OF MEXICO. MIDDLE TO UPPER LEVEL DRY AIR/SUBSIDENCE IS
EVIDENT ON CURRENT WATER VAPOR IMAGERY. TWO WEAK 1015 MB LOW
PRESSURE CENTERS IN THE GULF FROM 23N TO 27N BETWEEN 92W AND
95W WITH A WEAK FRONTAL BOUNDARY AT 31/1200 UTC HAVE GIVEN WAY
TO ONE 1015 MB TEXAS COAST LOW PRESSURE CENTER NEAR 27N96W AT
31/1500 UTC. A WARM FRONT STRETCHES FROM THE LOW CENTER TO
27N90W AND 27N85W. A TROUGH GOES FROM THE LOW CENTER TO 22N95W.

THE CARIBBEAN SEA...
BROAD MIDDLE TO UPPER LEVEL ANTICYCLONIC FLOW AND DRY
AIR/SUBSIDENCE COVER THE AREA. BROAD SURFACE CYCLONIC FLOW
IS EVIDENT IN THE LOW CLOUD MOVEMENTS SOUTH OF 17N. THE AREA
NORTH OF 17N AND WEST OF 80W APPEARS TO BE UNDER SURFACE-TO-
LOW LEVEL ANTICYCLONIC FLOW. CLUSTERS OF SCATTERED TO BROKEN
LOW TO MIDDLE LEVEL CLOUDS AND POSSIBLE SHOWERS IN LINES
OF SURFACE-TO-LOW LEVEL CONFLUENT FLOW ABOUND.

THE ATLANTIC OCEAN...
A DEEP LAYER TROUGH HAS MOVED INTO THE WESTERN ATLANTIC OCEAN
JUST EAST OF THE U.S.A. EAST COAST. THE TROUGH PASSES THROUGH
32N72W TO 27N76W. THIS TROUGH SUPPORTS A SURFACE TROUGH THAT
PASSES THROUGH 32N70W TO 30N74W TO CENTRAL FLORIDA ALONG 81W
FROM 27N TO 28N. A COLD FRONT TRAILS THIS TROUGH...AND THE
SOUTHERN POINT OF THIS FRONT IS 31N75W. COLD AIR STRATIFORM
CLOUDS ARE TO THE WEST OF THIS FRONT. UPPER LEVEL SOUTHWESTERLY
FLOW IS TO THE EAST OF THE BASE OF THE TROUGH NEAR 27N76W...
MOVING NORTHEASTWARD BEYOND 32N56W. SOME OF THE FLOW CONTINUES
EASTWARD...AND THEN SOUTHEASTWARD AS UPPER LEVEL ANTICYCLONIC
FLOW TOWARD 8N46W. THE EASTERN ATLANTIC OCEAN MIDDLE TO UPPER
LEVEL TROUGH CONTINUES...THROUGH 34N23W TO 27N23W TO 21N24W
TO THE SOUTHWESTERN AREA OF THE CAPE VERDE ISLANDS NEAR 14N26W
TO 11N26W. A SURFACE RIDGE PASSES THROUGH 33N30W TO A WEAKENING
1025 MB HIGH PRESSURE CENTER NEAR 26N40W TO 20N52W. THE MIDDLE
TO UPPER LEVEL SUPPORT FOR THE TROUGH THROUGH 32N41W TO 27N52W
IS OUT OF THE AREA NORTH OF 32N. A TROUGH CONTINUES FROM 27N52W
TO 21N72W...IN BETWEEN THE TURKS AND CAICOS ISLANDS AND HAITI.
THE CLOUD LINE MARKING THE COLD FRONT CONTINUES TO WEAKEN IN
AMOUNT OF CLOUDINESS.

$$
MT




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