[Tropical] Tropical Weather Discussion

[EMWIN Server]

AXNT20 KNHC 201744
TWDAT

TROPICAL WEATHER DISCUSSION
NWS NATIONAL HURRICANE CENTER MIAMI FL
105 PM EST SUN FEB 20 2011

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...METEOROLOGICAL ANALYSIS...WEATHER OBSERVATIONS...AND
RADAR.

BASED ON 1200 UTC SURFACE ANALYSIS AND SATELLITE IMAGERY THROUGH
1715 UTC.

...ITCZ...

THE INTERTROPICAL CONVERGENCE ZONE AXIS IS ANALYZED FROM THE
COAST OF LIBERIA NEAR 05N09W TO 02N20W TO 03N33W AND CONTINUES
SOUTH OF THE AREA AND EQUATOR TO THE COAST OF BRAZIL NEAR
03S42W. SCATTERED MODERATE AND ISOLATED STRONG CONVECTION IS
WITHIN 120 NM N OF THE AXIS BETWEEN 34N AND 39W.

...DISCUSSION...

GULF OF MEXICO...
A BROAD UPPER RIDGE COVERS THE GULF WATERS WITH THE MAIN AXIS
ALONG 92W. WATER VAPOR SATELLITE IMAGERY INDICATES VERY DRY AIR
OVER THE GULF UNDER MODERATE TO STRONG SUBSIDENCE WITH MAINLY
CLEAR SKIES ACROSS THE REGION THIS AFTERNOON. THE EXCEPTION IS
IN THE N CENTRAL GULF S OF LOUISIANA WHERE DENSE SEA FOG IS
OCCURRING DUE TO WARMER AIR MOVING OVER THE COOLER WATERS. THIS
FOG IS REDUCING VISIBILITIES TO LESS THAN ONE MILE. AT THE
SURFACE A RIDGE EXTENDS FROM NEAR APALACHEE BAY TO THE BAY OF
CAMPECHE ANCHORED BY HIGH PRES LOCATED OVER THE U.S. GREAT LAKES
REGION. THE RIDGE WILL BECOME ORIENTED ALONG 26N TO 27N TONIGHT
INTO MON AS NEW HIGH PRES FORMS IN THE ATLANTIC E OF FLORIDA. A
WEAK COLD FRONT WILL MOVE INTO THE NW GULF EARLY TUE MORNING
BECOMING STATIONARY LATE TUE OVER THE N GULF WATERS THEN
DISSIPATING WED AS RIDGING BUILDS SW FROM THE CAROLINAS.

CARIBBEAN SEA...
A MID TO UPPER LEVEL TROUGH EXTENDS FROM THE W CENTRAL ATLANTIC
SW ACROSS THE E CARIBBEAN WITH LIMITED MID LEVEL MOISTURE OUT
AHEAD OF THE AXIS. BROAD UPPER RIDGING EXTENDS FROM CENTRAL
COLOMBIA NW TOWARD NICARAGUA WITH VERY DRY AIR IN PLACE UNDER
THE RIDGE. SCATTERED SHOWERS ARE OCCURRING ACROSS THE BASIN AS
COLDER AIR ALOFT MOVES OVER THE WARMER CARIBBEAN WATERS. WEAK
SURFACE LOW PRES IS LOCATED ALONG THE NW COAST OF COLOMBIA
RESULTING IN STRONGER TRADES NEAR THE COAST BETWEEN THE LOW AND
SURFACE RIDGING N OF THE AREA. NEW ATLANTIC HIGH PRES FORMS N OF
THE AREA MON THROUGH WED WHICH WILL INCREASE TRADES ACROSS THE
CARIBBEAN. LARGE LONG PERIOD NW SWELL OF 10 TO 12 FEET WILL SEEP
THROUGH THE E CARIBBEAN ATLANTIC PASSAGES LATE MON SUBSIDING BY
LATE TUE.

ATLANTIC OCEAN...
AN UPPER TROUGH EXTENDS INTO THE AREA NEAR 32N57W TO 27N68W. A
REINFORCING UPPER TROUGH EXTENDS FROM AN UPPER CYCLONIC
CIRCULATION LOCATED WELL N OF THE AREA NE OF THE COAST OF
NEWFOUNDLAND TO NEAR 31N66W. MID TO UPPER LEVEL MOISTURE LOCATED
WITHIN 300 NM AHEAD OF THE FIRST TROUGH IS BEING ADVECTED FROM
THE SW TO THE NE AHEAD OF THE TROUGH AXIS. AN ATTENDANT SURFACE
COLD FRONT REACHES FROM NEAR 32N54W TO 26N70W WITH A REMNANT
SHEAR AXIS EXTENDING FROM THERE TO NEAR GRAND BAHAMA. SCATTERED
SHOWERS AREA OCCURRING WITHIN 60 NM AHEAD OF THE SURFACE
FEATURES. THE SECOND TROUGH WILL USHER IN A REINFORCING SURFACE
COLD FRONT TONIGHT THROUGH MON NIGHT WITH GALE FORCE WINDS
DEVELOPING BOTH AHEAD OF AND BEHIND THIS REINFORCING FRONT
BEGINNING AT 18 UTC THIS AFTERNOON DIMINISHING TO LESS THAN GALE
FORCE BY 00 UTC MON AS THE REINFORCING FRONT WEAKENS. MEANWHILE
ADDITIONAL SCATTERED SHOWERS ARE OCCURRING ALONG THE COASTS OF
EASTERN CUBA EASTWARD TO THE VIRGIN ISLANDS BEING OROGRAPHICALLY
ENHANCED AS THE N TO NE FLOW ENCOUNTERS THE LAND MASSES.

BROAD UPPER RIDGING COVERS THE MAJORITY OF THE REMAINDER OF THE
ATLANTIC W OF 30W. AN UPPER CYCLONIC CIRCULATION IS LOCATED NEAR
10N25W WITH A TROUGH EXTENDING S TO THE EQUATOR NEAR 20W.
CONVECTION IS BEING ENHANCED ALONG THE ITCZ BETWEEN THIS UPPER
RIDGE AND CYCLONE MAINLY BETWEEN 34W AND 39W.

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

$$
LEWITSKY




This weather bulletin was brought to you by:
www.nashvilleweather.net