[Tropical] Tropical Weather Discussion

[EMWIN Server]

AXNT20 KNHC 200559
TWDAT

TROPICAL WEATHER DISCUSSION
NWS NATIONAL HURRICANE CENTER MIAMI FL
105 AM 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 0000 UTC SURFACE ANALYSIS AND SATELLITE IMAGERY THROUGH
0515 UTC.

...ITCZ/MONSOON TROUGH...

THE MONSOON TROUGH EXTENDS ACROSS AFRICA AND ENTERS THE E
TROPICAL ATLC THROUGH THE COAST OF SIERRA LEONE TO 6N16W. THE
ITCZ CONTINUES FROM 5N17W TO 2N24W EQ34W 2S42W. ISOLATED SHOWERS
ARE FROM EQ TO 5N BETWEEN 7W AND 20W. SCATTERED SHOWERS ARE
EMBEDDED WITHIN THE ITCZ BETWEEN 23W AND 31W. SIMILAR CONVECTION
IS NW OF THE ITCZ S OF 5N BETWEEN 34W AND 50W. WIDELY SCATTERED
MODERATE/ISOLATED STRONG CONVECTION IS S OF THE ITCZ N OF 4S
BETWEEN 24W AND 39W.

...DISCUSSION...

GULF OF MEXICO...
AS OF 0300 UTC...A COLD FRONT EXTENDS FROM NE FLORIDA NEAR 30N81W
TO THE CENTRAL GULF OF MEXICO NEAR 25N90W TO TAMAULIPAS MEXICO
NEAR 24N97W. THE FRONT IS VERY WEAK AND NO CONVECTIVE
PRECIPITATION IS ASSOCIATED WITH IT. HOWEVER MOISTURE ADVECTION
FROM THE EAST PACIFIC MAY TRIGGER ISOLATED SHOWERS OVER THE
BASIN N OF 24N. RADAR IMAGERY DEPICT SCATTERED SHOWERS OVER S
FLORIDA AND THE STRAITS OF FLORIDA. ELSEWHERE...CLEAR SKIES
DOMINATE BEING SUPPORTED BY DRY AIR IN THE UPPER LEVELS. ALSO IN
THE UPPER LEVELS ZONAL FLOW PREVAILS OVER THE ENTIRE REGION.
EXCEPT FOR THE NE GULF N OF 26N E OF 87W...RETURN FLOW SPREADS
OVER THE REGION WITH WINDS OF 15-20 KT N OF THE FRONT AND 10-15
KT S OF THE FRONT. DURING THE NEXT 24 HOURS...THE PORTION OF THE
COLD FRONT OVER THE NE GULF WILL MOVE TO THE W ATLC WATERS WHILE
IT GRADUALLY WEAKENS. THE TAIL END OF THE COLD FRONT IS EXPECTED
TO RETROGRADE BACK N AS A WARM FRONT TO NE TEXAS WITH MORE
SHOWERS. ALSO RETURN FLOW IS EXPECTED TO CONTINUE DURING THIS
PERIOD.

CARIBBEAN SEA...
TRADEWINDS OF 20-25 KT SPREAD OVER CENTRAL-SOUTHERN AND EASTERN
CARIBBEAN REGIONS WHILE LIGHTER WINDS IN THE RANGE OF 10-15 KT
DOMINATE OVER THE WESTERN REGION. NEARLY WESTERLY FLOW AND VERY
DRY AIR IS DEPICTED IN THE UPPER LEVELS. THE UPPER LEVEL
CONDITIONS ARE HINDERING DEEP CONVECTION. HOWEVER LOW LEVEL
CLOUDINESS OVER THE NW CARIBBEAN AND EAST CARIBBEAN MAY BE
TRIGGERING ISOLATED SHOWERS. EXPECT LITTLE CHANGE OVER THE NEXT
24 HOURS.

ATLANTIC OCEAN...
SURFACE RIDGING DOMINATES THE W AND E ATLC ANCHORED BY A 1028 MB
HIGH LOCATED NEAR 30N60W. OVER THE CENTRAL ATLC A COLD FRONT
ENTER THE DISCUSSION AREA NEAR 30N37W AND THEN EXTENDS SW TO
27N44W AND 24N55W WHERE IT BECOMES A STATIONARY DYING FRONT THAT
CONTINUES WESTWARD TO 24N73W. THERE IS NO CONVECTIVE
PRECIPITATION ASSOCIATED TO THIS FRONTAL BOUNDARY BUT ISOLATED
SHOWERS ARE POSSIBLE ALONG THE FRONT. THIS FRONT IS BEING
SUPPORTED BY AN UPPER LEVEL BROAD AND SHALLOW TROUGH THAT
EXTENDS FROM 25N-31N WEST OF 42W. WATER VAPOR IMAGERY SHOWS VERY
DRY AIR COVERING ALMOST THE ENTIRE REGION WHICH IS FAVORING FAIR
WEATHER CONDITIONS AT THE SURFACE. OVER THE PERIOD OF 24
HOURS...THE COLD FRONT OVER THE NE GULF WILL DISPLACE OVER THE
WEST ATLC WATERS GENERATING SHOWERS IN THIS REGION WHILE THE
FRONTAL BOUNDARY IN THE CENTRAL ATLC GRADUALLY VANISHES.

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

$$
NR















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