000 AXNT20 KNHC 041746 TWDAT TROPICAL WEATHER DISCUSSION NWS TPC/NATIONAL HURRICANE CENTER MIAMI FL 105 PM EST SAT NOV 04 2007 TROPICAL WEATHER DISCUSSION FOR NORTH AMERICA...CENTRAL AMERICA...THE GULF OF MEXICO...THE CARIBBEAN SEA...NORTHERN 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. ...TROPICAL WAVES... TROPICAL WAVE IS ALONG 40W S OF 18N MOVING W 10-15 KT. A 1010 MB LOW HAS FORMED ALONG THE AXIS NEAR 12.5N. VISIBLE IMAGERY SHOWS A WELL DEFINED ENVELOPE OF LOW-LEVEL CYCLONIC TURNING. WHILE THE OVERALL WAVE SIGNATURE IS CLEAR...CONVECTION IS ISOLATED AT BEST WITHIN 180 NM E OF THE WAVE AXIS SHEARED BY MID TO UPPER WESTERLIES. SOME MODEL GUIDANCE SUGGESTS FRAGMENTATION OR SOME ENERGY ABSORPTION OF THIS WAVE AS A LARGE DEEP LAYER AREA OF LOW PRES...CURRENTLY JUST S OF THE AZORES...DIGS SW. TROPICAL WAVE IS HIGHLY TITLED ALONG 22N57W 7N52W MOVING W 10-15 KT...AS NOTED IN VISIBLE IMAGERY AND THE MIMIC TPW ANIMATION. THIS WAVE IS INTERACTING WITH AN UPPER LOW TO GENERATE SCATTERED SHOWERS AND TSTMS IN AN UPPER DIFFLUENT AREA TO THE E OF THE LOW FROM 16N-21N BETWEEN 51W-56W. THIS LOW-LEVEL FEATURE SHOWS UP NICELY IN THE SURROUNDING BUOY DATA WITH PRESSURES LOWEST...NEAR 1010 MB...ALONG THE ANALYZED AXIS AND A ENE TO SE WIND SHIFT. ...THE ITCZ... ITCZ AXIS IS CENTERED ALONG 7N12W 5N26W 5N35W 8N46W 9N61W. SCATTERED MODERATE CONVECTION IS FROM 8N-10N BETWEEN 29W-32W AND WITHIN 120 NM OF THE AXIS BETWEEN 44W-49W. SCATTERED SHOWERS AND TSTMS IS WITHIN 90 NM OF THE AXIS E OF 28W. DISCUSSION... GULF OF MEXICO... SWIFT UPPER ZONAL FLOW AND ABUNDANT DRY AIR ALOFT...BETWEEN A LARGE TROUGH OVER THE ERN U.S. AND FLAT E-W RIDGING OVER THE CARIB...DOMINATES THE GULF OF MEXICO TODAY. THIS STABLE PATTERN IS PROVIDING A VERY NICE DAY ACROSS MOST OF THE AREA. AT THE SFC...A 1025 MB HIGH IS ANALYZED OVER SE TEXAS. THIS IS ALLOWING WINDS TO BE OUT OF THE N TO NE ACROSS THE CENTRAL AND E GULF...STRONGEST NEAR 20 KT TOWARD THE YUCATAN CHANNEL AS NOTED IN AN 1130 Z QSCAT PASS. THIS FLOW IS ADVECTING A PLEASANTLY DRY FALL AIRMASS WITH DEW POINTS IN THE HIGH 30'S AND 40'S F ACROSS THE N GULF COAST AND IN THE 50'S F IN CENTRAL AND S FLA. IN THE WRN GULF...THE SFC FLOW IS STARTING TO VEER E MODIFYING THE AIRMASS. CARIBBEAN SEA... ACTIVE WEATHER IS CONFINED TO THE FAR W PORTION OF THE AREA. LATEST IR IMAGES AND LIGHTNING DATA REVEAL SCATTERED MODERATE CONVECTION OVER ERN HONDURAS AND THE NW CARIB FROM 15N-18N BETWEEN 83W-86W. THIS IS ASSOCIATED WITH A LOW PRES SYSTEM...ANALYZED 1006 MB...LOCATED NEAR THE COAST OF NORTHEASTERN NICARAGUA. WHILE SIGNIFICANT TROPICAL DEVELOPMENT IS NOT EXPECTED DUE TO THE PROXIMITY TO LAND...SQUALLY WEATHER WILL CONTINUE OVER HONDURAS AND NICARAGUA WITH THE POSSIBILITY OF HEAVY RAINS DURING THE NEXT DAY OR TWO. THESE RAINS COULD CAUSE LIFE-THREATENING FLASH FLOODS AND MUD SLIDES. AN EARLIER ASCAT PASS SHOWED ANOTHER CIRCULATION LOCATED FARTHER TO THE SE. SINCE THEN...THAT CIRCULATION APPEARS TO HAVE OPENED INTO A TROUGH EXTENDING SW FROM THE AFOREMENTIONED LOW TO 10N80W. LOW-LEVEL CONVERGENCE IS PRODUCING CLOUDINESS...SCATTERED SHOWERS AND TSTMS WITHIN 150 NM W OF THE BOUNDARY. THE TAIL END OF A FRONTAL SYSTEM IS STALLED FROM ERN CUBA TO 16N82W. STIFF NELY WINDS...SCATTERED CLOUDINESS AND ISOLATED SHOWERS ARE LOCATED WITHIN 180 NM NW OF THE FRONT. THE REMAINDER OF THE REGION...GENERALLY E OF 77W...IS RELATIVELY TRANQUIL UNDER THE INFLUENCE OF LIGHT TO MODERATE TRADE WIND FLOW AND STRONG N TO NWLY FLOW ALOFT BETWEEN AN UPPER RIDGE AND AN UPPER LOW JUST E OF THE AREA. THERE IS SOME SHOWER ACTIVITY...ASSOCIATED WITH THE THE UPPER LOW AND AND A TROPICAL WAVE...WHICH MAY MOVE ACROSS THE NRN LEEWARD ISLANDS LATER TODAY. ATLANTIC OCEAN... A COOLER AND DRIER AIRMASS IS IN PLACE OVER THE BAHAMAS AND FLORIDA...BEHIND A COLD FRONT WHICH ENTERS THE AREA NEAR 32N63W AND EXTENDS SW TO 23N73W THEN STATIONARY INTO THE CARIBBEAN. SCATTERED CLOUDS AND EMBEDDED ISOLATED SHOWERS ARE WITHIN 180 NM E OF THE FRONT. A CUT OFF UPPER LOW IS MEANDERING NEAR 17N58W. THE INTERACTION BETWEEN THIS UPPER SYSTEM AND A TROPICAL WAVE IN THE VICINITY IS PRODUCING SOME ACTIVITY...SEE ABOVE FOR DETAILS. FARTHER NE...A VERY LARGE DEEP LAYER 1003 MB LOW PRES SYSTEM IS CENTERED JUST S OF THE AZORES NEAR 37N29W. A COLD FRONT EXTENDS S-SW FROM THE LOW ALONG 32N22W 25N29W 24N40W. A WEAK TROUGH APPEARS TO HAVE BROKEN OFF FROM THE MAIN FRONTAL SYSTEM AND IS TRACKING W STEERED BY THE ELY TRADES CURRENTLY ALONG 56W FROM 24N-30N...WHICH SHOWED UP NICELY IN A RECENT ASCAT PASS. ONLY SCATTERED CLOUDS AND ISOLATED SHOWERS ARE NEAR THESE SYSTEMS. THE TRPCL E ATLC HAS A FAIR AMOUNT OF MID TO HIGH LEVEL CLOUDINESS EMBEDDED WITHIN BROAD FLAT UPPER RIDGING WHICH HAS BEEN SUPPRESSED FAR S ALONG 10N. THIS HAS ALLOWED UPPER WLYS TO SHEAR THE TROPICAL WAVE ALONG 40W. $$ CANGIALOSI