000 AXNT20 KNHC 171732 TWDAT TROPICAL WEATHER DISCUSSION NWS TPC/NATIONAL HURRICANE CENTER MIAMI FL 105 PM EST WED JAN 17 2007 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 1200 UTC SURFACE ANALYSIS AND SATELLITE IMAGERY THROUGH 1715 UTC. ...THE ITCZ... ITCZ AXIS IS CENTERED ALONG 2N AT THE PRIME MERIDIAN 5N18W 3N30W 2N40W EQ50W. SCATTERED MODERATE CONVECTION IS WITHIN 120 NM EITHER SIDE OF THE AXIS BETWEEN 32W-44W. ...DISCUSSION... GULF OF MEXICO... A COLD FRONT CONTINUES TO SLOWLY SEEP S AND AS OF 15 UTC WAS ANALYZED FROM NEAR MARCO ISLAND FL TO 25N84W THEN STATIONARY TO 25N93W CURVING SHARPLY S TO MEXICO NEAR 19N92W. SFC OBS AND A QSCAT PASS THIS MORNING HELPED LOCATE THIS BOUNDARY. THESE OBS ALSO SHOW GALE FORCE WINDS OCCURRING W OF THE FRONT S OF 25N...AS A STRONG GRAD PERSISTS BETWEEN THE FRONT AND A 1035 MB HIGH IN NE MEXICO. ELSEWHERE BEHIND THE FRONT...WINDS ARE ON THE STRONG SIDE...GENERALLY NELY BETWEEN 20-30 KT. DENSE LOW/MID LEVEL CLOUDINESS AND ISOLATED SHOWERS LINGER BEHIND THE FRONT W OF 89W. THIS INCLUDES MEXICO WHERE THINNING LOW CLOUDS ARE BANKED ACROSS THE SLOPES OF THE SIERRA MADRE. MORE ORGANIZED PRECIP EXISTS FURTHER N ACROSS TEXAS AND LOUISIANA ASSOCIATED WITH A LARGE MOISTURE PLUME ADVECTED BY THE UPPER LEVEL SUBTROPICAL JET FROM THE EPAC. THIS PRECIP IS IN THE FROZEN FORM WITH FREEZING RAIN AND/OR LIGHT SNOW BEING REPORTED AT SEVERAL STATIONS ...WHICH IS BY NO MEANS A COMMON OCCURRENCE FOR THAT PART OF THE COUNTRY. S OF THE FRONT...CONDITIONS ARE WARM AND HUMID WITH LIGHTER WINDS AND ONLY SCATTERED LOW TO MID LEVEL CLOUDS. OVER THE NEXT DAY OR TWO...NWP MODELS SHOW THE FRONT BECOMING DIFFUSE...NEARLY STATIONARY OR LIFTING N IN THE GULF AS THE UPPER SUPPORT/DYNAMICS CONTINUE TO PULL AWAY. CARIBBEAN SEA... TRADE WINDS IN THE S CARIBBEAN REMAIN STRONG BUT HAVE DROPPED JUST BELOW GALE FORCE AS CONFIRMED BY A 1042 UTC QSCAT PASS WHICH INDICATED E/NELY TRADES MAINLY IN THE 25-30 KT RANGE N OF COLOMBIA. THESE WINDS ARE EXPECTED TO REMAIN SIMILAR OVER THE NEXT COUPLE DAYS. OTHERWISE...VERY DRY AIR IN THE MID AND UPPER LEVELS COVERS THE ENTIRE REGION GENERATED BY STRONG CONFLUENCE ALOFT BETWEEN RIDGING TO THE N/NW...TROUGHING TO THE SW AND NE AND S-SWLY FLOW ACROSS THE SE CARIB. THE DRIEST AIR IS FROM 15N-20N BETWEEN 72W-85W. BENEATH THE STRONG MID-LEVEL CAP...PATCHES OF LOW LEVEL CLOUDS AND EMBEDDED ISOLATED SHOWERS ARE SCATTERED ACROSS THE SEA. OVERALL...NUMERICAL MODELS SHOW LITTLE CHANGE IN MOISTURE ACROSS THE CARIB OVER THE NEXT DAY OR SO AS DRY AIR ALOFT CONTINUES TO SUPPRESS CONVECTIVE ACTIVITY. ATLANTIC OCEAN... THE VERY BROAD MID TO UPPER LEVEL RIDGE IN THE W AND CENTRAL ATLC IS BEING SUPPRESSED S AS A DEEP LAYER TROUGH SLIDES E N OF IT. THE ASSOCIATED COLD FRONT CONTINUES TO MOVE AND AS OF 15 UTC WAS ANALYZED FROM JUST E OF BERMUDA TO S FLORIDA ALONG 32N65W 28N76W 26N80W. BEHIND THE FRONT...NLY WINDS ARE INCREASING TO 25 KT OR SO DUE TO THE TIGHTENED PRES GRAD SET UP BETWEEN THE FRONT AND A STRONG SFC RIDGE CENTERED IN THE OHIO VALLEY. SHOWER ACTIVITY IS LIMITED NEAR THE FRONT BUT DENSE LOW AND MID LEVEL CLOUDS AND ISOLATED SHOWERS EXIST BEHIND IT. A CUT OFF UPPER LEVEL LOW...ALSO WEAKENING THE MID-LEVEL RIDGE...IS CENTERED NEAR 26N53W. THIS UPPER LEVEL SYSTEM DOES HAVE A CLEAR SFC BOUNDARY ASSOCIATED WITH IT...WHICH IS ANALYZED ALONG 14N58W 24N50W. IR IMAGES SUGGEST AREAS OF SCATTERED SHOWERS ALONG AND TO THE E OF THE TROUGH BETWEEN 45W-52W FROM 21N-25N. DEBRIS MOISTURE IS THEN CARRIED SE AND AROUND THE BASE OF A SHARP UPPER LEVEL TROUGH EXTENDING FROM SPAIN TO 21N33W. THIS TROUGH DOES NOT APPEAR TO HAVE A SFC REFLECTION YET...BUT A KINK IN THE ISOBARIC PATTERN HAS DEVELOPED SO IT MAY BE FORMING. GFS SHOWS THIS TROUGH CUTTING OFF TONIGHT OR TOMORROW WHICH LOOKS REALISTIC BASED UPON ITS STEEPNESS. IN THE TROPICAL ATLC...EXTENSIVE WLY UPPER LEVEL FLOW ON THE N SIDE OF A VERY BROAD RIDGE IS THE RULE. THIS FLOW IS SPREADING SOME MID AND HIGH LEVEL CLOUDINESS...WITH POSSIBLE ISOLATED SHOWERS ...ACROSS THE OCEAN FROM 13N-17N. ELSEWHERE AT THE SFC...A 1028 MB HIGH DOMINATES THE CENTRAL AND ERN ATLC...INTERRUPTED BY THE SFC TROUGH MENTIONED. $$ CANGIALOSI