[Tropical] Tropical Weather Discussion

[EMWIN Server]

AXNT20 KNHC 201740
TWDAT

TROPICAL WEATHER DISCUSSION
NWS NATIONAL HURRICANE CENTER MIAMI FL
105 PM EST WED FEB 20 2013

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 1200 UTC SURFACE ANALYSIS AND SATELLITE IMAGERY THROUGH
1645 UTC.

...ITCZ/MONSOON TROUGH...

THE MONSOON TROUGH EXTENDS ACROSS AFRICA ENTERING THE TROPICAL
ATLC ALONG THE COAST OF SIERRA LEONE AT 8N13W TO 4N19W. THE ITCZ
BEGINS AT 4N19W AND CONTINUES TO THE EQUATOR AT 40W TO 1S47W.
SCATTERED MODERATE CONVECTION IS WITHIN 60 NM OF THE AXIS
BETWEEN 20W-35W...AND WITHIN 130 NM OF THE AXIS BETWEEN 41W-47W.

...DISCUSSION...

GULF OF MEXICO...
A WEAK FRONTAL BOUNDARY CONTINUES TO SKIM THE EASTERN GULF WITH
A COLD FRONT EXTENDING FROM 27N80W TO 26N86W WHERE IT BECOMES A
DISSIPATING STATIONARY BOUNDARY TO 27N91W AND A FORMING WARM
FRONT TO THE TEXAS COAST AT 28N97W...AS OF 1500 UTC. ONLY A FEW
POSSIBLE ISOLATED SHOWERS ARE NEAR THE AXIS. THE FRONT HAS LOST
MOST OF ITS UPPER LEVEL SUPPORT AS THE UPPER TROUGH HAS SHIFTED
EAST OF THE AREA WITH UPPER LEVEL RIDGING BUILDING OVER THE
AREA. DRY AIR ALOFT IS ALSO PRESENT OVER A GOOD PORTION OF THE
BASIN. SURFACE RIDGING IS TO THE NORTH OF THE FRONT COVERING
MUCH OF THE EASTERN CONUS. THIS PATTERN IS PROVIDING MAINLY
EASTERLY FLOW ACROSS THE AREA EXCEPT IMMEDIATELY NEAR THE COLD
FRONT. WIND SPEEDS ARE LIGHTER ACROSS THE SOUTHEAST CORNER
INCREASING IN SPEED TO 20-25 KT ACROSS THE NW CORNER. THE
FRONTAL BOUNDARY IS EXPECTED TO SPLIT WITH THE COLD FRONT
PUSHING EAST OF THE BASIN WHILE THE FORMING WARM FRONT LIFTS
NORTH AND JOINS THE NEXT FRONTAL SYSTEM WHICH WILL REACH THE NW
GULF EARLY FRIDAY.

CARIBBEAN SEA...
MOSTLY FAIR CONDITIONS ARE ACROSS THE CARIBBEAN TODAY DUE TO DRY
AIR ALOFT AROUND AN UPPER LEVEL RIDGE OVER THE WESTERN CARIBBEAN
AND A WEAK INVERTED UPPER TROUGH OVER THE EASTERN CARIBBEAN.
STRONG SUBSIDENCE IS ALSO NOTED OVER THE SW CARIBBEAN AND NORTH
OF VENEZUELA. A FEW ISOLATED SHOWERS ARE EMBEDDED WITHIN
TRADEWIND FLOW OF 15-20 KT. STRONGER WINDS UP TO 30 KT ARE ALSO
NORTH OF THE COLOMBIAN COAST. LITTLE CHANGE IS EXPECTED OVER THE
NEXT 24 HOURS.

ATLANTIC OCEAN...
A BROAD UPPER TROUGH COVERS THE WEST ATLC SUPPORTING A COLD
FRONT THAT ENTERS THE DISCUSSION AREA NEAR 32N71W TO 27N80W AND
CONTINUES INTO THE GULF OF MEXICO. ISOLATED SHOWERS ARE
IMMEDIATELY ALONG THE AXIS WITH AN AREA OF SHOWERS EAST OF THE
AXIS FROM 26N-30N BETWEEN 65W-70W. THE REMAINDER OF THE WEST
ATLC AND INTO THE CENTRAL ATLC IS DOMINATED BY SURFACE RIDGING
AROUND A 1026 MG HIGH NEAR 31N54W. THE RIDGE IS SUPPORTED BY
BROAD UPPER RIDGING WITH AXIS NEAR 55W. FARTHER EAST...A LARGE
UPPER LEVEL LOW COVERING THE NORTH ATLC SUPPORTS A COLD FRONT
THAT ENTERS THE DISCUSSION AREA NEAR 32N28W CONTINUING AROUND
THE RIDGE IN THE CENTRAL ATLC ALONG 28N40W 26N54W. ISOLATED
SHOWERS ARE IMMEDIATELY ALONG THE AXIS. UPPER LEVEL RIDGING
COVERS THE TROPICAL EAST ATLC ALONG 22W SUPPORTING WEAK SURFACE
RIDGING ACROSS THIS PORTION OF THE BASIN. BOTH FRONTAL
BOUNDARIES IN THE ATLC BASIN ARE EXPECTED TO MOVE EASTWARD OVER
THE NEXT FEW DAYS.

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

$$
WALTON




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