[Tropical] Tropical Weather Discussion

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AXNT20 KNHC 041743
TWDAT

TROPICAL WEATHER DISCUSSION
NWS TPC/NATIONAL HURRICANE CENTER MIAMI FL
105 PM EST SUN MAR 04 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
1715 UTC.

...ITCZ...

ITCZ AXIS IS CENTERED ALONG 10N14W 8N20W 3N30W EQ40W 5N51W.
CLUSTERS OF SCATTERED MODERATE CONVECTION ARE WITHIN 120-180 NM
EITHER SIDE OF THE AXIS BETWEEN 20W AND 40W...AND WITHIN 120-150
NM OF THE AXIS W OF 40W TO THE COAST OF BRAZIL.

...DISCUSSION...

GULF OF MEXICO...
A COLD FRONT IS MOVING SLOWLY ACROSS THE FLORIDA STRAITS AND
THE SE PORTION OF THE GULF. A LINE OF WIDELY SCATTERED SHOWERS
OVER THE STRAITS OF FLORIDA DEFINES THE LEADING EDGE OF THE
FRONT WHILE A SURGE OF COLD AIR AND EXTENSIVE AREA OF LOW AND
SOME MID LEVEL CLOUDS ARE FOUND BEHIND THIS FRONTAL SYSTEM. A
BROAD POSITIVELY TILTED MID-UPPER LEVEL TROUGH WHICH EXTENDS
FROM THE CANADIAN MARITIMES SOUTHWESTWARD THROUGH THE OHIO
VALLEY TO EASTERN TEXAS SUPPORTS THIS FRONTAL BOUNDARY. VERY
STRONG UPPER LEVEL WINDS ASSOCIATED WITH A SUBTROPICAL JETSTREAM
AHEAD OF THE TROUGH ARE TRANSPORTING A NARROW BAND OF UPPER
LEVEL MOISTURE FROM THE EPAC ACROSS N MEXICO AND THE NORTH GULF
STATES INTO THE W ATLC. DRY AIR/STRONG SUBSIDENCE IS NOTED OVER
THE GULF S OF THE STRONG JET/27N...WITH SATELLITE DERIVED
WINDS INDICATING CORE SPEEDS OF 125-140 KT. AT THE SURFACE
BUILDING HIGH PRESSURE OVER TEXAS AND THE NW CORNER OF THE GULF
CONTINUES TO PUSH THE ABOVE MENTIONED COLD FRONT SLOWLY SEWD.
THIS FEATURE IS EXPECTED TO BUILD FURTHER INTO THE W GULF TODAY
WITH STRONG NORTHERLY WINDS OF GALE FORCE OCCURRING OVER THE SW
GULF. BROKEN TO OVERCAST LOW LEVEL CLOUDS WITH LIGHT
RAIN/DRIZZLE ARE BANKED UP ALONG THE E SLOPE OF THE SIERRA MADRE
MOUNTAINS AND A STATIONARY FRONT IS INDICATED THERE.

CARIBBEAN...
AN EXPANSIVE MID/UPPER LEVEL HIGH IS CENTERED OVER E CUBA WITH
THE ASSOCIATED RIDGE AXIS EXTENDING ENE INTO THE SW ATLC. THIS
FEATURE COVERS THE ENTIRE CARIBBEAN AND IS ACCOMPANIED BY VERY
STRONG SUBSIDENCE/DRY AIR ESPECIALLY OVER THE E CARIBBEAN IN THE
VICINITY OF AN UPPER LEVEL TROUGH AXIS WHICH IS UNDERCUTTING THE
RIDGE AXIS AND EXTENDS THROUGH 14N61W TO THE NORTH COAST OF
COLOMBIA. PRESSURE GRADIENT BETWEEN THE SURFACE RIDGE OVER THE
ATLC AND THE 1005 MB SFC LOW PRESSURE LOCATED OVER N COLOMBIA IS
GENERATING STRONG EASTERLY TRADE WINDS ACROSS THE AREA. PATCHES
OF LOW LEVEL MOISTURE WITH EMBEDDED SHOWERS DRIVEN BY THESE
WINDS ARE MOVING WWD FROM THE TROPICAL N ATLC INTO THE CARIBBEAN
E OF 70W. SOME OF THESE SHOWERS HAVE SPREAD OVER PUERTO RICO
AND HISPANIOLA AS WELL AS JAMAICA AND PARTS OF CUBA. THE ATLC
RIDGE WILL CONTINUE TO MOVE EWD AND THE COLD FRONT CURRENTLY
OVER THE SE GULF WILL REACH THE NW CARIB/W CUBA TONIGHT FOLLOWED
BY STRONG GUSTY N WINDS OVER THE YUCATAN CHANNEL.

ATLANTIC...
STRONG ZONAL FLOW BETWEEN THE RIDGE OVER E CUBA AND THE BROAD
TROUGH OVER THE E CONUS IS SWEEPING OVER THE ATLC N OF 26N W OF
60W. THE AXIS OF THE UPPER RIDGE EXTENDS FROM THE CARIBBEAN INTO
THE W AND CENTRAL ATLC TO BEYOND 32N45W COVERING THE AREA N OF
15N W OF 45W. STRONG SUBSIDENCE AND VERY DRY UPPER AIR DOMINATE
THE REGION S OF 23N W OF 45W LIMITING SHOWER ACTIVITY E OF A
COLD FRONT THAT ENTERS THE FORECAST AREA NEAR 31N66W AND CROSSES
THE BAHAMAS NEAR ANDROS ISLAND INTO THE FLORIDA STRAITS. A
SURFACE RIDGE EXTENDS FROM A 1030 MB HIGH LOCATED NEAR 33N35W
SOUTHWEST TO NEAR 22N72W. A SHEARED MID/UPPER LEVEL TROUGH
EXTENDS FROM THE CANARY ISLANDS SW TO A DEVELOPING CYCLONIC
CIRCULATION NEAR 18N46W. THE TAIL END OF THE ASSOCIATED COLD
FRONT CLIPS THE REGION THROUGH 31N18W TO 27.5N30W. A WEAKENING
SURFACE TROUGH CROSSING THE WINDWARD ISLANDS. IT LIES ALONG 61W
FROM 12N-20N. ONLY ISOLATED LOW TOP SHOWERS ARE OCCURRING WITH
THIS TROUGH. AN UPPER RIDGE IS DOMINATING THE FAR E ATLC. WV AND
INFRARED IMAGERY REVEALS A BROAD BAND OF TRANSVERSE HIGH CLOUDS
AND POSSIBLE UPPER LEVEL TURBULENCE ASSOCIATED WITH A TROPICAL
JETSTREAM OVER THE DEEP TROPICS E OF 50W CROSSING S OF THE CAPE
VERDE ISLANDS.

$$
COBB






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