000 AXNT20 KNHC 160524 TWDAT TROPICAL WEATHER DISCUSSION NWS TPC/NATIONAL HURRICANE CENTER MIAMI FL 105 AM EST SAT DEC 16 2006 TROPICAL WEATHER DISCUSSION FOR NORTH AMERICA... CENTRAL AMERICA...THE GULF OF MEXICO...THE CARIBBEAN SEA... NORTHEASTERN SECTIONS OF SOUTH AMERICA...AND THE 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 0000 UTC SURFACE ANALYSIS AND SATELLITE IMAGERY THROUGH 0515 UTC. ...THE ITCZ... ITCZ AXIS IS ALONG 6N11W 4N30W 5N44W 5N53W. SMALL CLUSTERS OF ISOLATED MODERATE CONVECTION ARE WITHIN 180 NM EITHER SIDE OF THE AXIS BETWEEN 17W-22W AND BETWEEN 27W-36W. SCATTERED MODERATE IS WITHIN 180 NM N OF THE AXIS BETWEEN 40W-46W. ...DISCUSSION... THE GULF OF MEXICO... AN UPPER LEVEL SHORTWAVE TROUGH CONTINUES TO SLOWLY MOVE E NOW LOCATED FROM LOUISIANA SOUTHWESTWARD TO N CENTRAL MEXICO. A SUBTROPICAL JET ORIGINATES AT THE BASE OF THE TROUGH AND RACES ACROSS CENTRAL FLORIDA AND INTO THE W ATLC WITH CORE WINDS FROM 60 TO 80 KT BASED ON CIMSS SATELLITE DERIVED WINDS. COPIOUS MOISTURE ASSOCIATED WITH THIS UPPER LEVEL JET COVERS THE GULF E OF 88W. A SFC TROUGH...ANALYZED FROM THE NW BAHAMAS ACROSS THE STRAITS OF FLORIDA TO N OF THE YUCATAN CHANNEL NEAR 23N85W IS DEEPENING THE MOISTURE ACROSS THE SE GULF. IN FACT...DOPPLER RADAR FROM MIAMI AND KEY WEST DEPICT A LARGE SHIELD OF SCATTERED SHOWERS AND TSTMS MOVING TOWARD AND OVER S FLORIDA. DRY AIR ALOFT IS BEING ADVECTED INTO THE WRN GULF...W OF THE SHORTWAVE AXIS...STABILIZING THE ATMOSPHERE. A 1018 MB SFC HIGH IS LOCATED IN THE N GULF JUST S OF NEW ORLEANS NEAR 30N90W. THIS WEAK PRES PATTERN IS PRODUCING LIGHT NE TO ELY WINDS. THE SFC HIGH WILL SLIDE E...STRENGTHEN AND BECOME NEARLY STATIONARY OFF THE SE COAST LATE THIS WEEKEND INCREASING ELY WINDS SLIGHTLY. THE MOISTURE IN THE E GULF WILL CONTINUE TO MOVE E WITH THE SHORTWAVE TROUGH EVENTUALLY CLEARING THE ENTIRE REGION LATER TODAY OR SUN. THE CARIBBEAN SEA... CONDITIONS ACROSS THE CARIBBEAN ARE QUIET THIS MORNING. THE ONLY AREA OF ANY MENTIONABLE CLOUDINESS IS IN THE EXTREME NW PORTION WHERE BROKEN MULTILAYERED CLOUDS AND ISOLATED SHOWERS COVER THE AREA N OF 19N W OF 78W. THIS CLOUDINESS IS MAINLY CONTRIBUTED TO THE SFC TROUGH IN THE SE GULF AND STRONG UPPER LEVEL WINDS ON THE N SIDE OF AN UPPER HIGH CENTERED IN THE SW CARIBBEAN NEAR 16N80W. THE REMAINDER OF THE CARIBBEAN IS STABLE WITH PLENTY OF DRY AIR ALOFT NOTED ON WATER VAPOR IMAGERY...WITH THE DRIEST AIR OVER THE ERN CARIBBEAN WHERE UPPER LEVEL CONFLUENCE IS STRONGEST. THE TYPICAL LOW-LEVEL CLOUD STREAKS...UNDERNEATH THE MID-LEVEL CAP...EVEN APPEAR RATHER THIN BASED ON SHORTWAVE IR IMAGES. TRADE WINDS ARE MOSTLY IN THE 15-20 KT RANGE AND LITTLE CHANGE IS EXPECTED THRU THE WEEKEND. MOISTURE MAY INCREASE A SLIGHTLY IN THE ERN CARIBBEAN LATER TODAY AND SUN BUT OVERALL MAINLY DRY CONDITIONS ARE EXPECTED TO PREVAIL. THE ATLANTIC OCEAN... THE UPPER LEVEL PATTERN HAS BECOME A LITTLE MORE AMPLIFIED TODAY AND BASICALLY CONSISTS OF A LONGWAVE RIDGE/TROUGH PATTERN. WIDESPREAD MOISTURE...PRODUCED BY STRONG UPPER LEVEL WINDS E OF A SHORTWAVE TROUGH IN THE GULF AND A WEAKENING FRONTAL BOUNDARY/SFC TROUGH IN THE BAHAMAS AND THE STRAITS OF FLORIDA...IS SPREADING TO ABOUT 57W MAINLY N OF 23N. THE ATMOSPHERE CONSIDERABLY DRIES OUT E OF 57W AS THE UPPER LEVEL FLOW DEVELOPS A NLY COMPONENT ON THE W SIDE OF A LARGE TROUGH IN THE E ATLC. THIS DRY STABLE AIR ALOFT COVERS A LARGE PORTION OF THE REGION BETWEEN 25W-57W. AT THE SFC...A 1031 MB HIGH CENTERED NEAR 37N43W DOMINATES THE REGION HELPING TO PRODUCE MOSTLY FAIR WEATHER. IN THE E ATLC...AN OCCLUDED 1004 MB SFC LOW IS LOCATED NEAR 33N28W. A COLD FRONT ENTERS THE AREA NEAR 32N26W AND EXTENDS SWD ALONG 24N27W 14N39W. MOISTURE APPEARS MOST ORGANIZED WELL N OF THE LOW...OUTSIDE OF THE DISCUSSION AREA. SCATTERED SHOWERS ARE WITHIN 240 NM AHEAD OF THE COLD FRONT N OF 20N. THE MOST SIGNIFICANT WEATHER EFFECT ASSOCIATED WITH THIS LOW PRES SYSTEM IS THE STRONG WINDS AS A TIGHT PRES GRAD EXISTS BETWEEN THIS LOW AND THE HIGH TO IT'S NW PRODUCING NEAR GALE FORCE CONDITIONS IN THE REGION BETWEEN THE LOW AND 40W N OF 25N. STRONGER WINDS EXIST TO THE N OF THE AREA WHERE THE GRAD IS TIGHTER. THE REMAINDER OF THE SUBTROPICAL E ATLC IS UNDER A NARROW UPPER RIDGE WITH THE AXIS ALONG 18W KEEPING CONDITIONS RATHER TRANQUIL ACROSS THE CANARY ISLANDS AND WRN AFRICA. IN THE TROPICAL ATLC...EXTENSIVE ZONAL FLOW ON THE N SIDE OF VERY BROAD RIDGING IS THE RULE WITH CONVECTION CONFINED TO THE ITCZ. $$ CANGIALOSI