[Tropical] Tropical Weather Discussion

[EMWIN Server]

AXNT20 KNHC 201135
TWDAT

TROPICAL WEATHER DISCUSSION
NWS NATIONAL HURRICANE CENTER MIAMI FL
705 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 0600 UTC SURFACE ANALYSIS AND SATELLITE IMAGERY THROUGH
1115 UTC.

...ITCZ/MONSOON TROUGH...

THE MONSOON TROUGH EXTENDS ACROSS AFRICA AND ENTERS THE E
TROPICAL ATLC THROUGH THE COAST OF LIBERIA TO 4N17W. THE ITCZ
CONTINUES FROM 4N18W TO 1N24W EQ36W EQ48W. ISOLATED SHOWERS ARE
S OF THE MONSOON TROUGH BETWEEN 8W AND 13W AND N OF THE EQUATOR.
WIDELY SCATTERED MODERATE CONVECTION IS WITHIN 260 NM EITHER
SIDE OF THE ITCZ BETWEEN 23W AND 48W.

...DISCUSSION...

GULF OF MEXICO...
AS OF 0900 UTC...A COLD FRONT EXTENDS ACROSS CENTRAL FLORIDA AND
THEN SW IN THE GULF NEAR 27N84W AND 26N87W WHERE A DISSIPATING
STATIONARY FRONT CONTINUES WESTWARD TO 27N93W. RADAR IMAGERY IS
SHOWING SCATTERED SHOWERS ALONG THE COLD FRONT BOUNDARY
EXTENDING APPROXIMATELY 100 NM SW OF TAMPA. A PREFRONTAL SURFACE
TROUGH IS PRODUCING A LINE OF SHOWERS OVER THE STRAITS OF
FLORIDA. BROKEN TO OVERCAST SKIES COVER THE GULF WEST OF 90W
SUPPORTED BY MOISTURE ADVECTION FROM THE EAST PACIFIC. RADAR
IMAGERY SHOWS THAT SCATTERED SHOWERS ARE RAPIDLY APPROACHING THE
NW GULF BEING ASSISTED BY STRONG UPPER LEVEL ZONAL FLOW. RETURN
FLOW SPREADS OVER THE REGION WITH WINDS OF 15-20 KT N OF THE
FRONTAL BOUNDARY AND 5-15 KT ELSEWHERE. DURING THE NEXT 24
HOURS...THE COLD FRONT WILL DISPLACE OVER THE W ATLC WATERS
WHILE IT GRADUALLY WEAKENS. THE DYING STATIONARY 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 THE CENTRAL AND EASTERN
CARIBBEAN REGIONS WHILE LIGHTER WINDS IN THE RANGE OF 10-15 KT
DOMINATE OVER THE WESTERN REGION. IN THE SOUTHERN REGION AND
ALONG THE COLOMBIA COAST NEAR GALE FORCE WINDS ARE PRESENT.
NEARLY WESTERLY FLOW AND VERY DRY AIR IS DEPICTED IN THE UPPER
LEVELS. THE UPPER LEVEL CONDITIONS ARE HINDERING DEEP CONVECTION
IN THE ENTIRE REGION. HOWEVER LOW LEVEL CLOUDINESS MAY BE
TRIGGERING ISOLATED SHOWERS IN THE YUCATAN CHANNEL...NE AND
ALONG THE COAST OF HONDURAS AS WELL AS S OF PUERTO RICO BETWEEN
64W AND 69W. EXPECT LITTLE CHANGE OVER THE NEXT 24 HOURS.

ATLANTIC OCEAN...
SURFACE RIDGING DOMINATES THE ATLC WATERS E OF 75W NORTH OF 18N
ANCHORED BY A 1026 MB HIGH LOCATED NEAR 31N58W. WEST OF THE HIGH
PRESSURE A COLD FRONT ENTERS THE DISCUSSION AREA NEAR 30N77W AND
EXTENDS SW TO THE EASTERN FLORIDA COAST NEAR 29N80W. NO
CONVECTIVE PRECIPITATION IS ASSOCIATED WITH THIS PORTION OF THE
FRONT AT THIS TIME. AN UPPER LEVEL TROUGH OVER THE EASTERN CONUS
AND THE W ATLC N OF 31N IS SUPPORTING THIS COLD FRONT. EAST OF
THE HIGH PRESSURE ANOTHER COLD FRONT EXTENDS ACROSS THE CENTRAL
ATLC FROM 30N35W TO 27N42W 25N49W AND 25N54W WHERE IT BECOMES A
DYING STATIONARY FRONT THAT CONTINUES TO 27N61W. THERE IS NO
CONVECTIVE PRECIPITATION ASSOCIATED TO THIS FRONTAL BOUNDARY AT
THIS TIME BUT ISOLATED SHOWERS ARE POSSIBLE ALONG THE FRONTAL
BOUNDARY. THIS FRONT IS BEING SUPPORTED BY AN UPPER LEVEL BROAD
TROUGH N OF 25N OVER THE CENTRAL ATLC. WATER VAPOR IMAGERY SHOWS
VERY DRY AIR COVERING ALMOST THE ENTIRE REGION WHICH IS FAVORING
FAIR WEATHER CONDITIONS AT THE SURFACE. OVER A PERIOD OF 24
HOURS...THE COLD FRONT OVER THE WEST ATLC WATERS WILL CONTINUE
AN EASTWARD TRACK AND SHOWERS ARE EXPECTED TO CONTINUE/INCREASE.
THE FRONTAL BOUNDARY OVER THE CENTRAL ATLC WILL GRADUALLY
VANISHES.

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

$$
NR




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