[Tropical] Tropical Weather Discussion

[EMWIN Server]

AXNT20 KNHC 172340
TWDAT

TROPICAL WEATHER DISCUSSION
NWS NATIONAL HURRICANE CENTER MIAMI FL
705 PM EST SUN FEB 17 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
2315 UTC.

...ITCZ/MONSOON TROUGH...

THE MONSOON TROUGH EXTENDS ACROSS AFRICA ENTERING THE E TROPICAL
ATLC THROUGH SIERRA LEONE TO 04N20W WHERE THE ITCZ CONTINUES
TO 1N30W THEN S OF THE EQUATOR NEAR 38W TO NE BRAZIL. SMALL
CLUSTERS OF SCATTERED MODERATE/ISOLATED STRONG CONVECTION ARE
FROM 4N TO 7N BETWEEN 11W AND 18W. SIMILAR CONVECTION IS FOUND
FROM THE EQUATOR TO 3N BETWEEN 28W-38W.

...DISCUSSION...

GULF OF MEXICO...
A 1029 MB HIGH PRES LOCATED NEAR 30N87W EXTENDS A RIDGE SW TO
THE BAY OF CAMPECHE COVERING THE ENTIRE GULF WATERS AND THE
STATE OF FLORIDA. COLD AIR STRATOCUMULUS CLOUDS...DUE TO THE
ADVECTION OF COLD AIR OVER RELATIVELY WARM WATERS...COVER THE
GULF MAINLY S OF 27N E OF 94W TO OFF THE FLORIDA PENINSULA WHERE
A DRY AND COLD AIR MASS PREVAILS. EASTERLY SURFACE WINDS ARE
BANKING LOW LEVEL CLOUDS WITH ISOLATED SHOWERS ALONG THE COAST
OF MEXICO TO THE E SLOPES OF THE SIERRA MADRE MOUNTAINS. THE
MOST RECENT SCATTEROMETER DATA SHOW NORTHERLY WINDS OF 20-25 KT
OVER THE EASTERN GULF WHILE SOUTHERLY RETURN FLOW HAS ALREADY
ESTABLISHED OVER THE NW PORTION OF THE REGION. EXPECT THE RETURN
FLOW TO SPREAD EWD AND INCREASE TO 20-25 KT WITH HIGHER GUSTS ON
MON AS THE HIGH PRES MOVES TOWARD THE WESTERN ATLC. THE NEXT
COLD FRONT IS FORECAST TO MOVE INTO THE NW GULF TUE THEN STALL
AND DISSIPATE OVER NORTHERN GULF WATERS WED. ALOFT...BROAD UPPER
TROUGH OVER THE E CONUS DIGS S INTO FLORIDA AND WESTERN CUBA. A
RIDGE DOMINATES MEXICO AND THE WESTERN GULF.

CARIBBEAN SEA...
A COLD FRONT HAS MOVED ACROSS CUBA AND THE CARIBBEAN SEA AND NOW
EXTENDS FROM EASTERN CUBA TO NE NICARAGUA. SCATTEROMETER PASSES
INDICATE NLY WINDS IN THE 20 TO 25 KT RANGE WITH HIGHER GUSTS W
OF THE FRONT WHILE FRESH TO STRONG TRADE WINDS DOMINATE THE
REMAINDER OF THE BASIN. THIS FRONT WILL REACH FROM THE WINDWARD
PASSAGE TO THE COAST OF NICARAGUA TONIGHT WHERE IT WILL STALL
AND DISSIPATE THROUGH MON. VISIBLE SATELLITE PICTURES REVEALS A
TONGUE OF DRY AND COLD AIR COVERING THE STATE OF FLORIDA AND THE
STRAITS OF FLORIDA AND ALMOST REACHING THE COAST OF WESTERN
CUBA. IF THIS TREND CONTINUES TONIGHT AND THE COLD AIR INVADES
WEST-CENTRAL CUBA...EXPECT TEMPERATURES BELOW 10 DEGREES CELSIUS
ACROSS THE PROVINCES OF HAVANA AND MATANZAS OVERNIGHT. COLD AIR
STRATOCUMULUS CLOUDS ARE ALSO NOTICED BEHIND THE COLD FRONT
IMPLYING THAT A COLD AIR MASS HAS INVADED THE NW CARIBBEAN. THE
NLY WINDS BEHIND THE COLD FRONT ARE TRANSPORTING PATCHES OF LOW
LEVEL CLOUDS WITH EMBEDDED LIGHT TO MODERATE SHOWERS INTO PARTS
OF HONDURAS AND NICARAGUA. IN THE UPPER LEVEL...THE TROUGH OVER
THE EASTERN CONUS DIPS S OVER THE NW CARIBBEAN N OF 20N
SUPPORTING THE AFOREMENTIONED COLD FRONT. NEAR ZONAL WESTERLY
FLOW ALOFT DOMINATES THE REMAINDER OF THE CARIBBEAN SEA. WATER
VAPOR SATELLITE IMAGERY CONTINUES TO SHOW VERY STRONG SUBSIDENCE
AND DRY STABLE AIR ALOFT E OF 75 ACROSS THE REMAINDER OF THE
BASIN. STRONG HIGH PRESSURE IN THE WAKE OF THE FRONT WILL
MAINTAIN FRESH TO STRONG TRADE WINDS MAINLY ACROSS THE EAST AND
CENTRAL CARIBBEAN THROUGH AT LEAST TUE WITH THE STRONGEST WINDS
OF 25-30 KT...AS USUAL...NEAR THE COAST OF COLOMBIA.

ATLANTIC OCEAN...
THE PREVIOUSLY MENTIONED BROAD UPPER LEVEL TROUGH SUPPORTS A
STRONG COLD FRONT THAT ENTERS THE DISCUSSION AREA AT 17/1800 UTC
NEAR 31N63W EXTENDING SW THROUGH THE SE BAHAMAS AND EASTERN CUBA
INTO THE CARIBBEAN SEA. GALE FORCE WINDS ARE STILL BLOWING W OF
THE FRONT...PARTICULARLY N OF 29N TO 74W. THE 1718 UTC OSCAT
PASS ALONG WITH SURFACE DATA CONFIRMED THE PRESENCE OF THESE
STRONG WINDS. THIS GALE EVENT IS FORECAST TO END IN ABOUT 6
HOURS. A WIDE BAND OF MULTILAYERED CLOUDS WITH EMBEDDED SHOWERS
IS ASSOCIATED WITH THE FRONT. THE NORTHERN PORTION OF THE FRONT
WILL CONTINUE TO MOVE EWD WHILE THE SOUTHERN PART WILL STALL AND
DISSIPATE BETWEEN THE SE BAHAMAS AND HISPANIOLA ON MON. STRONG
HIGH PRES FOLLOWS THE FRONT AND WILL SHIFT EASTWARD JUST N OF
31N MON CROSSING NEAR BERMUDA TUE. E OF THE FRONT...A 1025 MB
HIGH PRES IS CENTERED NEAR 30N40W AND IS EXPECTED TO REMAIN
NEARLY STATIONARY OVER THE NEXT 24 HOURS. THIS SYSTEM EXTENDS A
RIDGE OVER MOST OF THE E AND CENTRAL ATLC. FRESH TO STRONG TRADE
WINDS ARE NOTED ON THE SOUTHERN PERIPHERY OF THE RIDGE.
ALOFT...AN UPPER RIDGE COVERS THE CENTRAL ATLC. A BROAD UPPER
TROUGH IS OVER THE E ATLC AND EXTENDS FROM 31N23W ALL THE WAY SW
TO NEAR BARBADOS IN THE WINDWARD ISLANDS. THIS TROUGH SUPPORTS A
DISSIPATING COLD FRONT CURRENTLY LOCATED BETWEEN THE MADEIRA AND
THE CANARY ISLANDS. STRONG SWLY FLOW IS NOTED ON THE SOUTH SIDE
OF THE TROUGH AXIS. THESE WINDS INCREASE TO 90-110 KT OVER
WESTERN AFRICA. THE NEXT COLD FRONT WILL MOVE INTO THE NW
PORTION OF THE FORECAST AREA EARLY WED.


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

$$
GR






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