000 AXNT20 KNHC 181751 TWDAT TROPICAL WEATHER DISCUSSION NWS TPC/NATIONAL HURRICANE CENTER MIAMI FL 205 PM EDT SUN OCT 18 2009 TROPICAL WEATHER DISCUSSION FOR NORTH AMERICA...CENTRAL AMERICA...GULF OF MEXICO...CARIBBEAN SEA...NORTHERN SECTIONS OF SOUTH AMERICA...AND 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... A NEW TROPICAL WAVE IS INTRODUCED ALONG 21W S OF 16N MOVING W AT 15 KT. THE WAVE COINCIDES WITH A DEEP LAYER MOISTURE MAXIMUM OBSERVED IN TOTAL PRECIPITABLE WATER IMAGERY. VISIBLE SATELLITE IMAGERY ALSO DEPICTS LOW TO MID LEVEL CYCLONIC TURNING ALONG THE WAVE AXIS. A LARGE AREA OF SCATTERED MODERATE CONVECTION IS OVER THE NORTHERN EXTENT OF THE WAVE TO INCLUDE THE EASTERN CAPE VERDE ISLANDS FROM 12N-18N BETWEEN 16W-24W. TROPICAL WAVE IS ALONG 33W S OF 14N MOVING W 15 KT. THE WAVE COINCIDES WITH A DEEP LAYER MOISTURE MAXIMUM OBSERVED IN TOTAL PRECIPITABLE WATER IMAGERY. SATELLITE IMAGES ALSO INDICATE CYCLONIC FLOW IN THE VICINITY OF THE WAVE AXIS AT 11N. ISOLATED MODERATE CONVECTION IS FROM 8N-11N BETWEEN 30W-34W. TROPICAL WAVE IS ALONG 56W S OF 13N MOVING W 20 KT. SATELLITE IMAGERY INDICATES BROAD LOW-LEVEL CYCLONIC FLOW ABOUT THE WAVE AXIS. THE WAVE ALSO COINCIDES WITH A LOW-AMPLITUDE DEEP LAYER MOISTURE MAXIMUM OBSERVED IN TOTAL PRECIPITABLE WATER IMAGERY. SCATTERED SHOWERS ARE S OF TRINIDAD FROM 6N-10N BETWEEN 55W-62W. TROPICAL WAVE IS ALONG 80W S OF 17N MOVING W 15 KT. THE WAVE LIES WITHIN A BROAD AREA OF DEEP MOISTURE OVER THE WRN CARIBBEAN OBSERVED IN TOTAL PRECIPITABLE WATER IMAGERY...AS WELL AS BROAD LOW LEVEL CYCLONIC FLOW INDICATED IN SATELLITE IMAGERY. AN UPPER LEVEL TROUGH OVER THE EASTERN PACIFIC ALONG 90W IS PROVIDING A DIFFLUENT ZONE ALOFT MOSTLY W OF THE WAVE AXIS. SCATTERED MODERATE TO ISOLATED STRONG CONVECTION IS OVER THE SW CARIBBEAN AND CENTRAL AMERICA FROM 5N-16N BETWEEN 79W-84W. ...THE ITCZ... ITCZ AXIS IS CENTERED ALONG 15N17W 15N20W 10N27W 10N33W 7N40W 8N56W 8N60W. BESIDES THE CONVECTION MENTIONED IN THE TROPICAL WAVE SECTION...SCATTERED MODERATE/ISOLATED STRONG CONVECTION IS FROM 7N-9N BETWEEN 18W-20W. ...DISCUSSION... THE GULF OF MEXICO... A 1031 MB HIGH CENTERED OVER ARKANSAS NEAR 35N92W IS PRODUCING SURFACE RIDGING OVER THE ENTIRE GULF OF MEXICO. 20 KT NORTHERLY WINDS ARE OVER THE THE GULF WITH BROKEN TO OVERCAST COLD AIR STRATOCUMULUS CLOUDS S OF 29N. COOL OVERNIGHT TEMPERATURES OVER FLORIDA HAVE NOW WARMED UP WITH DIURNAL HEATING. IN THE UPPER LEVELS...AN UPPER LEVEL TROUGH IS OVER THE ENTIRE GULF OF MEXICO AND NW CARIBBEAN SUPPORTING THE SURFACE COLD FRONT. STRONG SUBSIDENCE IS OVER THE N GULF N OF 24N. CONSIDERABLE UPPER LEVEL MOISTURE IS OVER THE S GULF S OF24N. EXPECT...THE SURFACE HIGH TO MOVE E AND CONTINUE TO PRODUCE SURFACE RIDGING WITH 15-20 KT NE WINDS OVER THE NEXT 24 HOURS. THE CARIBBEAN SEA... A TROPICAL WAVE IS ALONG 80W PRODUCING CONVECTION OVER THE SW CARIBBEAN. SEE ABOVE. A COLD FRONT EXTENDS FROM CENTRAL CUBA TO NW HONDURAS ALONG 22N78W 20N84W 16N88W. ISOLATED MODERATE CONVECTION IS WITHIN 60 NM OF THE FRONT. 25 KT NORTHERLY WINDS ARE OVER THE YUCATAN CHANNEL AND NW CARIBBEAN N OF THE COLD FRONT. GENTLE BREEZE TRADEWINDS ARE JUST S OF THE COLD FRONT. FRESH TRADEWINDS ARE OVER THE CENTRAL AND E CARIBBEAN E OF 80W. SCATTERED MODERATE CONVECTION IS S OF JAMAICA FROM 15N-17N BETWEEN 75W-78W. SCATTERED SHOWERS ARE S OF HISPANIOLA FROM 16N-18N BETWEEN 68W-71W. IN THE UPPER LEVELS...AN UPPER LEVEL HIGH IS CENTERED OVER THE SW CARIBBEAN NEAR 13N78W. SIGNIFICANT UPPER LEVEL MOISTURE IS OVER THE W CARIBBEAN W OF 70W. STRONG SUBSIDENCE IS OVER THE E CARIBBEAN. EXPECT...THE COLD FRONT TO EXTEND FROM E CUBA TO E HONDURAS IN 24 HOURS WITH CONVECTION. ALSO EXPECT THE TROPICAL WAVE TO MOVE W AND PRODUCE MORE CONVECTION OVER THE SW CARIBBEAN. THE ATLANTIC OCEAN... A COLD FRONT ENTERS THE DISCUSSION AREA NEAR 32N69W AND EXTENDS SW TO CENTRAL CUBA ALONG 27N74W 22N78W. ISOLATED MODERATE CONVECTION IS WITHIN 60 NM OF THE FRONT. SCATTERED MODERATE CONVECTION IS ALSO E OF THE CENTRAL BAHAMAS FROM 24N-27N BETWEEN 74W-76W. A 1023 MB HIGH IS OVER THE CENTRAL ATLANTIC NEAR 33N49W. A SURFACE TROUGH IS FURTHER E FROM 32N40W TO 26N40W 20N44W. SCATTERED SHOWERS ARE WITHIN 45 NM OF THE TROUGH. ANOTHER SURFACE TROUGH IS OVER THE E ATLANTIC ALONG 30N26W 24N33W. A WEAK 1019 MB HIGH IS FURTHER E NEAR 27N24W. IN THE UPPER LEVELS...AN UPPER LEVEL TROUGH IS OVER THE W ATLANTIC N OF 24N AND W OF 70W. AN UPPER LEVEL HIGH IS CENTERED NEAR 31N53W. AN UPPER LEVEL LOW IS OVER THE CENTRAL ATLANTIC NEAR 27N35W. ANOTHER UPPER LEVEL LOW IS CENTERED N OF THE CANARY ISLANDS NEAR 33N15W. EXPECT...MORE CONVECTION ALONG THE ITCZ ESPECIALLY E OF 40W OVER THE NEXT 24 HOURS. $$ FORMOSA