000 AXNT20 KNHC 130541 TWDAT TROPICAL WEATHER DISCUSSION NWS TPC/NATIONAL HURRICANE CENTER MIAMI FL 205 AM EDT THU APR 13 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...WEATHER OBSERVATIONS... RADAR...AND METEOROLOGICAL ANALYSIS. BASED ON 0000 UTC SURFACE ANALYSIS AND SATELLITE IMAGERY THROUGH 0530 UTC. ...ITCZ... ITCZ AXIS IS CENTERED ALONG 6N10W 2N20W EQ30W EQ40W 2S45W. A SMALL CLUSTER OF MODERATE CONVECTION HAS FORMED WITHIN 50 NM OF THE AXIS BETWEEN 17W-18W. OTHERWISE...ISOLATED/SCATTERED SHOWERS ARE WITHIN 250 NM OF THE AXIS. THE MOST ORGANIZED ACTIVITY IS MAINLY S OF THE AXIS BETWEEN 20W-35W. ...DISCUSSION... THE GULF OF MEXICO... MID-UPPER LEVEL RIDGING COVERS MEXICO...THE CENTRAL U.S. AND MUCH OF THE GULF OF MEXICO. HIGH LEVEL MOISTURE IS FAIRLY WIDESPREAD ACROSS MUCH OF THE AREA EXCEPT FOR THE SE CORNER WHERE STRONG SUBSIDENCE IS HOLDING ON. THIS UPPER LEVEL MOISTURE IS ADVECTED FROM THE EPAC ACROSS MEXICO AND THEN SSWARD ON THE E SIDE OF THE RIDGE IN THE GULF. A FEW SHOWERS MAY BE EMBEDDED IN THIS MOISTURE ESPECIALLY N OF 26N. AT THE SURFACE...A RIDGE DOMINATES THE AREA PRODUCING GENERALLY FAIR WEATHER. SURFACE HIGH PRESSURE IS EXPECTED TO REMAIN IN CONTROL ACROSS THE AREA THRU FRI. THEREAFTER...THE HIGH PRES SYSTEMS WILL MOVE TO THE EAST OF THE REGION ALLOWING S/SW RETURN FLOW TO DEVELOP POSSIBLE ENHANCING SOME SHOWER ACTIVITY IN THE N GULF OVER THE WEEKEND. THE CARIBBEAN SEA AND THE ATLANTIC OCEAN WEST OF 60W... AN UPPER TROUGH TO THE E OF THE GULF RIDGE HAS BEEN STUCK IN THE NW CARIBBEAN MUCH OF THE WEEK. THIS TROUGH APPEARS TO HAVE BECOME SOME-WHAT CUT-OFF IN THE AREA. A 1011 MB SFC LOW IS LOCATED IN THE E BAHAMAS NEAR 22N71W AND SITS ON A STATIONARY FRONT WHICH EXTENDS NEWD FROM THE LOW TO BEYOND 32N56W. AN UPPER LOW IS CENTERED TO THE W OF THE SFC LOW IN THE CENTRAL BAHAMAS. UPPER LEVEL DIVERGENCE AND SFC FORCING IS PRODUCING A SHIELD OF OVERCAST SKIES...SCATTERED SHOWERS AND POSSIBLE TSTMS FROM 21N-32N BETWEEN 59W-73W. THE MOST ORGANIZED SHOWER ACTIVITY IS WITHIN 200 NM OF THE STATIONARY FRONT AND THE NEAR THE UPPER LOW N OF CUBA. A SFC TROUGH IS DRAPED FROM THE LOW SWD OVER HISPANIOLA. SAN JUAN DOPPLER RADAR INDICATES A BATCH OF SOLID MODERATE RAIN WITH EMBEDDED TSTMS TO THE W OF THE ISLAND. CONSIDERABLE MOISTURE IS DRAWN NWD FROM THE EPAC AND S AMERICA ON THE E SIDE OF THE TROUGH AXIS AND IS RACING NEWARD MOVING INTO THE DEEP MOISTURE N OF THE CARIBBEAN ISLANDS. VERY DRY/STABLE AIR IS TO THE W OF THE TROUGH AXIS ACROSS THE NW CARIBBEAN KEEPING SKIES MOSTLY CLEAR FROM CUBA TO NICARAGUA. GFS SUGGESTS THAT THE SFC LOW WILL BEGIN TO PULL NEWARD THU NIGHT AS THE UPPER TROUGH BEGINS TO FLATTEN. THE UNSETTLED WEATHER WILL CONTINUE TO SHIFT SLIGHTLY EWD TOMORROW BEFORE BECOME SOMEWHAT DIFFUSE BY THE WEEKEND. THE DEEPEST MOISTURE WILL CONTINUE TO BE MAINLY TO THE N OF THE ISLANDS. THE REST OF THE ATLANTIC OCEAN... A RIDGE/TROUGH/RIDGE UPPER LEVEL PATTERN DOMINATES THE REMAINDER OF THE ATLANTIC OCEAN. A RATHER BROAD FLATTENING RIDGE STRETCHES FROM S AMERICA TO BEYOND 32N48W. SCATTERED STRATOCUMULUS CLOUDS ARE FAIRLY WIDESPREAD UNDER THE RIDGE. AN DEEP-LAYER TROUGH COVERS A GOOD PORTION OF THE CENTRAL AND EASTERN ATLC WATERS...NAMELY FROM 20W-40W N OF 20N. THE ONLY SFC FEATURE TO MENTION IN THE AREA IS A 1016 MB LOW UNDERNEATH THE UPPER TROUGH. THERE ARE SOME SCATTERED SHOWERS SPIRALING AROUND THE LOW MOSTLY WITHIN 200 NM OF THE CENTER. AN 80-100 KT SWLY JET ORIGINATES ON THE S SIDE OF THE UPPER LOW AND STRETCHES TO N AFRICA NEAR 34N6W. UPPER LEVEL DIFFLUENCE IS PRODUCING AN AREA OF SHOWERS AND TSTMS TO THE RIGHT OF THE AXIS FROM 24-33N BETWEEN 13W-23W. THIS UPPER LOW IS EXPECTED TO RACE NEWARD LEAVING A NEAR ZONAL WESTERLY UPPER LEVEL PATTERN ACROSS THE CENTRAL AND E ATLC BY SAT. A RATHER LARGE UPPER HIGH IS LOCATED TO THE S OF THE DEEP-LAYER TROUGH OVER W AFRICA WITH PLENTY OF DRY AIR ALOFT OVER THE W PART OF THE CONTINENT BETWEEN 7N-18N. BROAD WEAK RIDGING EXISTS IN THE TROPICAL ATLC LIMITING CONVECTION IN THE ITCZ. $$ CANGIALOSI