[Tropical] Tropical Weather Discussion

[EMWIN Server]

AXNT20 KNHC 170000
TWDAT

TROPICAL WEATHER DISCUSSION
NWS NATIONAL HURRICANE CENTER MIAMI FL
705 PM EST SAT FEB 16 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 1800 UTC SURFACE ANALYSIS AND SATELLITE IMAGERY THROUGH
2345 UTC.

...ITCZ/MONSOON TROUGH...

THE MONSOON TROUGH EXTENDS ACROSS AFRICA AND EMERGES INTO THE E
TROPICAL ATLC OVER SIERRA LEONE NEAR 8N13W THEN ALONG 6N15W TO
3N23W WHERE THE ITCZ CONTINUES ALONG 2N30W THEN S OF THE EQUATOR
NEAR 36W/37W TO THE COAST OF SOUTH AMERICA. LARGE CLUSTERS OF
SCATTERED TO LOCALLY NUMEROUS MODERATE/STRONG CONVECTION EXTEND
FROM THE SOUTHERN COAST OF AFRICA TO 4S E OF THE PRIME MERIDIAN.
SCATTERED MODERATE/ISOLATED STRONG CONVECTION IS FROM THE
EQUATOR TO 4N BETWEEN 8W-11W. SCATTERED MODERATE CONVECTION WAS
NOTED FROM THE EQUATOR TO 5N W OF 45W TO THE COAST OF SOUTH
AMERICA.

...DISCUSSION...

GULF OF MEXICO...
A SHARPENING UPPER TROUGH OVER THE E CONUS WITH MAIN AXIS ALONG
85W IS DIGGING INTO THE EASTERN GULF. THIS AMPLIFIED TROUGH IS
SUPPORTING A STRONG RAPIDLY MOVING COLD FRONT THAT AS OF
2100 UTC EXTENDS FROM NAPLES FLORIDA TO THE BAY OF CAMPECHE NEAR
21N94W. THIS FRONT IS EXPECTED TO CLEAR THE GULF OF MEXICO WITHIN
THE NEXT SEVERAL HOURS. THE FRONT WAS USHERING STRONG NW WINDS OF
20-30 KT OVER MOST OF THE GULF E OF 90W WITH SEVERAL NOAA BUOYS
REPORTING SEAS OF 10 FT. THE STRONG NORTHERLY WINDS WERE ALSO
BANKING LOW CLOUDS WITH AREAS OF EMBEDDED RAIN OVER THE FAR SW
GULF S OF 23N...THE BAY OF CAMPECHE AND WESTWARD TO THE SLOPES
OF THE SIERRA MADRE. SKIES HAVE CLEARED OVER THE NW THIRD OF THE
GULF IN THE WAKE OF A BUILDING 1032 MB SURFACE HIGH CENTERED
OVER LAREDO TEXAS. HIGH PRES BUILDS OVER THE GULF SUN WITH WINDS
DECREASING OVER THE ENTIRE BASIN. AS THE HIGH MOVES E ON MON
EXPECT SOUTHERLY WINDS TO INCREASE AHEAD OF A WEAKER COLD FRONT
SLATED TO REACH THE NW GULF MON NIGHT OR TUE.

CARIBBEAN SEA...
A BROAD UPPER RIDGE CONTINUES TO DOMINATE MOST OF THE CARIBBEAN
AND CURRENTLY EXTENDS FROM AN ANTICYCLONE NEAR 13N77W NE ACROSS
HISPANIOLA INTO THE W-CENTRAL ATLC. WATER VAPOR SATELLITE
IMAGERY CONTINUES TO SHOW VERY STRONG SUBSIDENCE AND DRY STABLE
AIR ALOFT ACROSS THE BASIN WITH THE EXCEPTION OF UPPER LEVEL
MOISTURE ACROSS THE YUCATAN CHANNEL. A WEAK COLD FRONT ENTERS
THE CARIBBEAN FROM THE SW ATLC ACROSS CUBA JUST E OF THE ISLE OF
YOUTH ALONG 20N84W TO THE GULF OF HONDURAS NEAR ROATAN.
SCATTERED SHOWERS ARE WITHIN 60-90 NM W OF THE FRONT. A WEAK
PRESSURE PATTERN PERSISTS ACROSS THE REMAINDER OF THE BASIN WHICH
HAS ALLOWED THE FRESH TO STRONG TRADE WINDS OVER THE CENTRAL
CARIBBEAN TO ABATE SOMEWHAT. A 1628 UTC OSCAT PASS INDICATED
EASTERLY WINDS OF 20 KT E OF 75W...WITH 25 KT WINDS WITHIN 60 NM
OF THE COAST OF COLOMBIA. A STRONGER REINFORCING COLD FRONT OVER
THE SE GULF IS EXPECTED TO SWEEP THROUGH THE YUCATAN CHANNEL
LATER TONIGHT AND OVERTAKE THE EXISTING WEAKER FRONT BY SUNRISE
SUN. THE MERGED FRONT WILL EXTEND FROM THE WINDWARD PASSAGE TO
THE E COAST OF NICARAGUA SUN MORNING THEN STALL AND BECOMING
DIFFUSE IN THE SAME AREA MON.

ATLANTIC OCEAN...
SHARPENING UPPER LEVEL TROUGH OVER THE E CONUS IS BEGINNING TO
EMERGE INTO THE FAR NW ATLC. 250 MB WINDS OF 150-175 KT
INDICATED THE PRESENCE OF A POWERFUL POLAR JETSTREAM WHICH WAS
CONTRIBUTING TO RAPID CYCLOGENESIS OFF THE NC COAST. A STRONG
COLD FRONT EXTENDED FROM THE DEVELOPING SURFACE LOW AND ENTERS
THE AREA NEAR 32N78W TO THE FLORIDA EAST COAST NEAR CAPE
CANAVERAL. STRONG COLD AIR BEHIND THE FRONT WILL RESULT IN
RAPIDLY INCREASING NW WINDS WHICH WILL REACH GALE FORCE OVER THE
NEXT FEW HOURS OVER THE FAR NW OFFSHORE WATERS ZONES. WINDS HAVE
INCREASED TO 25-27 KT OVER THE PAST HOUR AT BUOYS 41009...41010
AND 41012 WITH SEAS BUILDING UP TO 8 FT. FURTHER EAST A WEAKER
SLOW MOVING COLD FRONT EXTENDS FROM NEAR 32N70W EXTENDING ACROSS
THE CENTRAL BAHAMAS THEN INTO THE CARIBBEAN ACROSS THE N COAST
OF CUBA NEAR 23N80W. SCATTERED SHOWERS ARE WITHIN 75 NM W OF THE
FRONT. A WEAK SURFACE TROUGH FROM 32N66W TO 25N71W WITH LITTLE
IN THE WAY OF SENSIBLE WEATHER ASSOCIATED WITH IT. THE STRONGER
COLD FRONT IS EXPECTED TO OVERTAKE THE WEAKER FRONT OVERNIGHT
TONIGHT AND EARLY SUN WITH GALE FORCE WINDS EXPANDING EASTWARD
OVER THE OFFSHORE WATERS N OF 29N. THE UPPER RIDGE OVER THE
CARIBBEAN EXTENDS ACROSS HISPANIOLA TO BEYOND 32N48W. A BROAD
UPPER TROUGH NE OF DISCUSSION AREA SUPPORTS A COLD FRONT WHICH
ENTERS THE E PORTION OF THE DISCUSSION AREA THROUGH 32N26W TO
28N40W. A NARROW UPPER TROUGH IS TO THE S ACROSS THE E ATLC
EXTENDING FROM AN UPPER LOW OVER AFRICA NEAR 27N7W ALONG 23N25W
INTO THE TROPICS TO NEAR 13N48W. A LARGE SURFACE RIDGE DOMINATES
THE ATLC E OF THE FRONTS AND SURFACE TROUGH AND ANCHORED BY A
1024 MB HIGH NEAR 30N44W.

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

$$
COBB




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