000 AXNT20 KNHC 271745 TWDAT TROPICAL WEATHER DISCUSSION NWS TPC/NATIONAL HURRICANE CENTER MIAMI FL 105 PM EST TUE NOV 27 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. ...THE ITCZ... THE ITCZ AXIS IS CENTERED ALONG 8N13W 6N29W 5N45W 2N51W. SCATTERED MODERATE CONVECTION IS WITHIN 90 NM N AND 60 NM S OF THE AXIS BETWEEN 16W-25W. DISCUSSION... GULF OF MEXICO... A COLD FRONT CONTINUES TO PROPAGATE ACROSS THE GULF ANALYZED FROM THE TAMPA BAY AREA TO 24N88W THEN STATIONARY TO S MEXICO NEAR 18N94W. WHILE MOSAIC DOPPLER RADAR IS NOT DETECTING MORE THAN AN ISOLATED SHOWER NEAR THE FRONT IT IS REVEALING SCATTERED SHOWERS AND ISOLATED TSTMS IN THE FL STRAITS...THE KEYS AND THE FAR SE GULF AHEAD OF THE BOUNDARY. THERE IS A CONSIDERABLE AIRMASS CHANGE FROM THE LOWER 80'S F IN S FLORIDA TO THE UPPER 40'S AND LOWER 50'S F ACROSS THE N GULF COAST DRIVEN BY BRISK NLY WINDS. SAT IMAGERY SHOWS A WIDESPREAD BROKEN STRATOCUMULUS CLOUD DECK BEHIND THE FRONT...INDICATIVE OF THE STABLE LOW TO MID-LEVEL ENVIRONMENT. THERE ARE LIKELY SCATTERED SHOWERS AND TSTMS IN THE SW BAY OF CAMPECHE AND OVER COASTAL MEXICO FROM 18N-20N BETWEEN 94W-96W NEAR THE FRONTAL BOUNDARY AND ENHANCED BY A SLIGHT DIFFLUENT FLOW ALOFT AS IS VEERS FROM S TO SW ON THE NW SIDE OF A CARIBBEAN HIGH. CARIBBEAN SEA... THE ONLY AREA OF ORGANIZED ACTIVE WEATHER IS CONFINED TO THE FAR SW PORTION ROUGHLY S OF 14N W OF 80W WHICH INCLUDES PANAMA ...COSTA RICA AND THE SRN HALF OF NICARAGUA. LIGHTNING DATA DETECTS SOME TSTM ACTIVITY EMBEDDED IN THE AREA OF COLD CLOUD TOPS SEEN ON IR DATA. THERE ARE A FEW COMBINING ELEMENTS WHICH ARE HELPING TO SUSTAIN THIS ACTIVITY. ONE IS AN UPPER DIFFLUENT PATTERN BETWEEN SLY FLOW ON THE W SIDE OF A HIGH OVER CUBA AND WLY FLOW ON THE SW EDGE OF A DIGGING TROUGH IN THE CENTRAL ATLC. THE OTHER FACTOR IS GOOD LOW-LEVEL CONVERGENCE WHERE THE STRONG ELY TRADES IN THE S CARIB AND LIGHTER SWLY WINDS IN THE ERN-MOST TROPICAL EPAC MERGE. THE REMAINDER OF THE SEA APPEARS VERY TRANQUIL IN WATER VAPOR IMAGERY...ESPECIALLY THE NE PORTION...WHERE ABUNDANT VERY DRY AIR ALOFT IS FILTERING IN ON THE SW SIDE OF THE BROAD CENTRAL ATLC TROUGH. HOWEVER...THIS IS SOMEWHAT DECEIVING AS THERE ARE SCATTERED LOW-LEVEL CLOUD STREAMERS...WHICH CONTAIN QUICK MOVING SHOWERS...BENEATH THIS STRONG MID-LEVEL CAP AS NOTED IN VISIBLE IMAGERY AND SAN JUAN DOPPLER RADAR. THE THICKEST CLOUD STREAMERS ARE LOCATED NEAR PUERTO RICO...HISPANIOLA AND THE LESSER ANTILLES WHICH ARE MORE DIRECTLY EXPOSED TO THE ATLC NE-ENE FETCH. ATLANTIC OCEAN... STRONG 1037 MB SFC HIGH PRES IS CENTERED N OF THE AREA NEAR 40N40W. TIGHT PRES PATTERN ON THE S SIDE OF THE HIGH IS PRODUCING MODERATE TO STRONG ELY WINDS ACROSS MUCH OF THE SUBTROPICS. THE ONLY NOTABLE INTERRUPTION IN THIS STRONG RIDGING IS A LOW-LEVEL TROUGH ALONG 31N39W 20N40W. WINDS ARE LIKELY STRONGEST JUST W OF THIS BOUNDARY...DUE TO THE ENHANCED GRADIENT. THIS LOW-LEVEL TROUGH IS BEING SUPPORTED BY A FAIRLY WELL DEFINED UPPER SHORTWAVE WHICH IS AIDING IN THE FORMATION OF SCATTERED SHOWERS FROM 21N-27N BETWEEN 37W-41W. THE AFOREMENTIONED SHORTWAVE IS EMBEDDED WITHIN A VERY BROAD MID TO UPPER TROUGH WHICH BASICALLY COVERS MUCH OF THE CENTRAL ATLC...HOWEVER...IT WILL LIKELY BEGIN TO CUT OFF SOON SOMEWHERE NEAR 26N54W. UPPER DIFFLUENCE AND SWLY FLOW ON THE E SIDE OF THE TROUGH IS GENERATING AND TRANSPORTING SCATTERED SHOWERS AND ISOLATED TSTMS FROM 19N-29N BETWEEN 50W-57W. A MAINLY DRY COLD FRONT HAS MOVED INTO THE FAR NW CORNER OF THE AREA FROM 32N77W TO CENTRAL FLORIDA. MORE ON THIS FEATURE IN THE GULF OF MEXICO SECTION ABOVE. SFC RIDGING IS UNINTERRUPTED IN THE E ATLC EXTENDING SW FROM THE MAIN HIGH CENTER MENTIONED ABOVE. THE MID AND UPPER PATTERN IS MAINLY ZONAL BETWEEN RIDGING NEAR THE EQUATOR AND A LARGE UPPER LOW IN THE SW MEDITERRANEAN SEA. THIS PATTERN IS PRODUCING SOME HIGH LEVEL CLOUDINESS FROM 14N-25N E OF ABOUT 30W. $$ CANGIALOSI