000 AXNT20 KNHC 272332 TWDAT TROPICAL WEATHER DISCUSSION NWS TPC/NATIONAL HURRICANE CENTER MIAMI FL 705 PM EST THU DEC 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 1800 UTC SURFACE ANALYSIS AND SATELLITE IMAGERY THROUGH 2315 UTC ...THE ITCZ... ITCZ AXIS IS CENTERED ALONG 7N11W 4N22W 2N35W EQUATOR47W. SCATTERED MODERATE CONVECTION IS WITHIN 90 NM N OF THE AXIS BETWEEN 13W-19W AND WITHIN 150 NM S OF THE AXIS BETWEEN 30W-33W. ...DISCUSSION... THE GULF OF MEXICO... A SLOW MOVING WARM FRONT STRETCHES ACROSS THE N GULF FROM S TEXAS TO THE FLA PANHANDLE ALONG 28N97W 27N90W 31N86W. ISENTROPIC LIFT IS PRODUCING A RATHER DENSE AREA OF LOW CLOUDS...WITH LIKELY EMBEDDED ISOLATED SHOWERS...TO THE N OF THE FRONT IN THE NW GULF. DOPPLER RADAR REVEALS AN ABSENCE OF ACTIVITY...EXCEPT FOR A SMALL LINE ALONG A PREFRONTAL TROUGH JUST S OF THE FL PANHANDLE TO BUOY 42039. IN THE MID AND UPPER LEVELS....A JET CUTS ACROSS THE REGION ADVECTING A PLUME OF MOISTURE WITHIN 300 NM S OF A LINE FROM BROWNSVILLE TEXAS TO TALLAHASSEE FLORIDA. AN UPPER TROUGH LIES UPSTREAM OVER THE ROCKIES AND WILL BE A PLAYER IN THE WEATHER PATTERN TOMORROW AS IT SUPPORTS A COLD FRONT WHICH IS ANTICIPATED TO ENTER THE NW CORNER IN THE MORNING HOURS. MODELS ARE NOT EXPECTED MUCH SE PROGRESS OF THIS FRONT...HOWEVER...AS MOST OF THE UPPER DYNAMICS TRACK NE OVER THE CENTRAL U.S. THE CARIBBEAN SEA... SPRAWLING MID TO UPPER RIDGE IS ANCHORED ACROSS THE ENTIRE REGION CENTERED NEAR 13N80W. THIS UPPER SYSTEM IS ENHANCING WIDESPREAD DRY AIR ALOFT ESPECIALLY E OF 68W AND OVER THE NW CORNER WHERE THE FLOW ALOFT BECOMES CONFLUENT. THIS STABLE AIRMASS IS SUPPRESSING THE DEVELOPMENT OF DEEP CLOUDINESS ... EXCEPT FOR SOME PATCHES AND EMBEDDED SCATTERED SHOWERS/ISOLATED TSTMS OVER THE SW CARIB S OF 12N BETWEEN 77W-82W...MAINLY GENERATED BY LOW-LEVEL CONVERGENCE. SHALLOWER AREAS OF MOISTURE ARE BETWEEN JAMAICA AND HONDURAS...NEAR THE COAST OF THE YUCATAN PENINSULA N OF 18N...AND N OF 15N E OF 66W DRIVEN BY MODERATE TO STRONG TRADES. THESE WINDS ARE EXPECTED TO STRENGTHEN TOMORROW AND THE WEEKEND AS HIGH PRES BUILDS N OF THE REGION. THE ATLANTIC OCEAN... HIGHLY AMPLIFIED DEEP LAYER RIDGE/TROUGH/RIDGE PATTERN EXISTS ACROSS THE SUBTROPICAL AND TROPICAL ATLC BASIN. THE W ATLC IS DOMINATED BY RIDGING WITH THE MID AND UPPER AXIS EXTENDING NWD FROM THE CARIB THRU BERMUDA. PATCHY HIGH LEVEL CLOUDS ARE ROTATING AROUND THE NRN BRANCH STAYING CONFINED N OF 25N W OF 50W. IN THE LOW-LEVELS...HIGH PRES CENTERS CONSISTS OF A 1026 MB NEAR 31N55W...AND A PAIR OF 1021 MB HIGHS NEAR 31N76W AND 34N74W. A WEAK TROUGH LINE RUNS BETWEEN THE HIGHS FROM 31N69W TO 25N77W PRODUCING A WIND SHIFT AND SCATTERED CLOUDS. TROUGHING CONTROLS THE PATTERN BETWEEN 30W AND ABOUT 50W...STRETCHING FARTHER W IN THE TROPICS...DUE TO A VERTICALLY STACKED NEARLY STATIONARY 1013 MB LOW NEAR 26N38W. SFC TROUGHS EXTEND BOTH S AND NE OF LOW. SCATTERED SHOWERS AND TSTMS ARE MOST ORGANIZED ALONG THESE BOUNDARIES AND N OF THE LOW CENTER GENERALLY FROM 22N-30N BETWEEN 32W-39W. COMPUTER MODELS SHOW LITTLE MOVEMENT OF THIS VERTICALLY STACKED SYSTEM AS IT GETS CUT OFF FROM THE PROGRESSIVE PATTERN. THE FAR E ATLC...LIKE THE W ATLC...IS DOMINATED BY RIDGING. HOWEVER...THERE IS QUITE A BIT MORE CLOUDINESS AND EMBEDDED SCATTERED SHOWERS HERE MAINLY BETWEEN THE CAPE VERDE AND THE CANARY ISLANDS...FROM 16N-27N E OF 25W...DUE TO AN UPPER JET STREAKING ACROSS THE AREA. $$ CANGIALOSI