000 AXNT20 KNHC 252338 TWDAT TROPICAL WEATHER DISCUSSION NWS TPC/NATIONAL HURRICANE CENTER MIAMI FL 805 PM EDT SUN MAR 25 2007 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...METEOROLOGICAL ANALYSIS... WEATHER OBSERVATIONS...AND RADAR. BASED ON 1800 UTC SURFACE ANALYSIS AND SATELLITE IMAGERY THROUGH 2315 UTC. ...ITCZ... ITCZ AXIS IS CENTERED ALONG 6N10W 3N21W 2N36W 1N47W EQ50W. ONLY ISOLATED SHOWERS AND TSTMS EXIST WITHIN 90 NM EITHER SIDE OF THE AXIS. MORE IMPRESSIVE CONVECTIVE WEATHER IS FURTHER S FROM THE EQ TO 3S BETWEEN 12W-19W ASSOCIATED WITH A SPEED CONVERGENCE BOUNDARY AND INLAND OVER NE SOUTH AMERICA. ...DISCUSSION... GULF OF MEXICO... AN AMPLIFIED MID TO UPPER LEVEL RIDGE IS PARKED ACROSS THE GULF AND REMAINS DOWNSTREAM OF A SHARP UPPER LEVEL TROUGH OVER THE SWRN U.S. AND BAJA. ABUNDANT MOISTURE IS BEING ADVECTED BETWEEN THESE FEATURES ACROSS CENTRAL MEXICO AND INTO THE SOUTH CENTRAL STATES BY A STRONG SUBTROPICAL JET. DOPPLER RADAR AND LIGHTNING DATA DETECT A GOOD AMOUNT OF TSTM ACTIVITY IN THE AREA OF GREATEST DIFFLUENCE OVER N MEXICO AND SW TEXAS. NOT MUCH OF THIS DEEP MOISTURE IS AFFECTING THE GULF...IN FACT THERE APPEARS TO BE ONLY PATCHY HIGH CLOUDS W OF 86W. AT THE SFC...STRONG HIGH PRES CENTERED OVER THE SE U.S. EXTENDS SW ACROSS THE ENTIRE AREA. THIS SFC HIGH...ALONG WITH THE EXTENSIVE UPPER LEVEL RIDGING...IS PROMOTING WIDESPREAD FAIR WEATHER ACROSS THE REGION. THE SFC FLOW REMAINS MODERATE TO FRESH (11-21 KT ON THE BEAUFORT SCALE) OUT OF THE E TO SE. THESE WINDS HAVE LEVELED OFF THE SEAS IN THE 3-6 FT RANGE. WAVE SPECTRA ACROSS THE GULF ARE GENERALLY DOMINATED BY STEEP WIND WAVES WITH PEAK PERIODS MOSTLY IN THE 5-7 SEC BAND. LARGER AND STEEPER WAVES SHOULD BE ANTICIPATED IN THE STRAITS OF FLORIDA WITH THE ELY FLOW AGAINST THE OPPOSING GULF STREAM. OVER THE NEXT FEW DAYS...THE MID LEVEL RIDGE WILL SLOWLY SLIDE E. AS IT DOES SO...THE COMBINATION OF SWLY FLOW ALOFT AND LOW-LEVEL RETURN FLOW WILL SUPPORT MORE MOISTURE IN THE NW GULF. ELSEWHERE MOSTLY FAIR WEATHER IS EXPECTED TO CONTINUE. CARIBBEAN... SCATTERED SHOWERS AND TSTMS CONTINUE TO AFFECT JAMAICA ...CENTRAL/ERN CUBA...HISPANIOLA AND THE SURROUNDING WATERS AS A VERY SLOW MOVING UPPER LEVEL LOW IS SPINNING OVER THE WINDWARD PASSAGE. ENHANCING THE MESSY WEATHER IS A PERSISTENT SFC TROUGH ANALYZED ALMOST DIRECTLY UNDERNEATH THE UPPER CYCLONE EXTENDING FROM THE ERN BAHAMAS ACROSS THE WINDWARD PASSAGE TO 14N76W. UPPER LEVEL DIFFLUENCE TO THE E OF THE UPPER LOW AND LOW-LEVEL CONVERGENCE ALONG THE SFC BOUNDARY ARE THE ELEMENTS PRODUCING THE UNSETTLED WEATHER OUTLINED ABOVE. TO THE S AND W OF THE UPPER LOW AND SFC TROUGH...MOSTLY FAIR WEATHER IS THE RULE UNDER WIDESPREAD STRONG SUBSIDENCE AND SFC HIGH PRES RIDGING POKING SWD FROM THE GULF. THE MODERATE TO FRESH TRADES IN THIS REGION HAVE VEERED MORE TO THE N AND NE...IN RESPONSE TO THE NEARBY TROUGH...POOLING LOW CLOUDS AND EMBEDDED ISOLATED SHOWERS IN THE EXTREME SW CARIB AND OVER PANAMA AND COSTA RICA. THE ERN CARIB IS ALSO IN AN UPPER DIFFLUENT ZONE BUT QUITE A BIT WEAKER THAN THE N CENTRAL CARIB. IN ACCORDANCE...THE MOISTURE PLUME IS THINNER AND CONSISTS MOSTLY OF OVERCAST SKIES AND ISOLATED SHOWERS/TSTMS. THE TRADES HERE ARE FROM THE MUCH MORE TYPICAL ELY DIR AND ARE FAIRLY MODERATE. A FAIR AMOUNT OF MOISTURE IS LIKELY TO PERSIST FOR A COUPLE MORE DAYS AS THE UPPER LOW WEAKENS SLOWLY AND SHIFTS SLIGHTLY TO THE E. ATLANTIC... THE CONTINUED UNSETTLED WEATHER IN THE WRN AND CENTRAL ATLC HAS BEEN SUPPRESSED S COMPARED TO THE PAST COUPLE OF DAYS. SCATTERED SHOWERS AND ISOLATED TSTMS ARE NOW MAINLY FROM 22N-27N BETWEEN 45W-76W EXCEPT BETWEEN 67W-76W WHERE THE SHOWERS MAY BE A LITTLE MORE NUMEROUS IN NATURE AND EXTEND MUCH FURTHER S INTO THE CARIB. AS EXPLAINED IN THE CARIB SECTION...THE FEATURES PRODUCING THIS ACTIVITY CONSIST OF AN UPPER LEVEL CUT OFF LOW IN THE VICINITY OF ERN CUBA AND A STUBBORN SFC TROUGH ANALYZED ALONG 28N61W 23N69W ACROSS THE ERN BAHAMAS AND INTO THE WINDWARD PASSAGE. BOTH OF THESE FEATURES HAVE BEEN SLOW TO MOVE OVER THE PAST FEW DAYS AND ARE RESPONSIBLE FOR THE EXTENDED PERIOD OF SHOWERY WEATHER. THE TIGHTENED PRES GRADIENT BETWEEN THE TROUGH AND HIGH PRES OVER THE SE U.S. IS PRODUCING 15-25 KT NE WINDS NEAR THE BAHAMAS AND ATLC WATERS FROM 20N-29N W OF THE SFC TROUGH. A REINFORCING COLD FRONT...ASSOCIATED WITH A DEEPENING 1000 MB LOW NEAR 39N58W...IS APPROACHING BERMUDA AND WILL EXPAND THE REGION OF HIGH NE WINDS IN THE WRN ATLC LATER TONIGHT AND TOMORROW. THIS COLD FRONT IS FORECAST TO MERGE WITH THE SFC TROUGH EARLY TOMORROW SUPPRESSING THE MOISTURE PLUME FURTHER S. HOWEVER MOST OF THE MODELS STILL SHOW A SIGNIFICANT AMOUNT OF MOISTURE HANGING AROUND S OF 23N FOR A FEW MORE DAYS. IN THE ERN AND CENTRAL ATLC...A 1028 MB SFC HIGH NEAR 35N35W CONTROLS THE PATTERN. THE UPPER FLOW IS FAIRLY ZONAL BETWEEN BROAD RIDGING OVER AFRICA AND THE EQUATORIAL ATLC AND A SERIES OF UPPER LOWS AND SHORTWAVES N OF THE REGION. THIS COMBINATION IS KEEPING THE WEATHER FAIRLY TRANQUIL ACROSS THE BULK OF THE REGION. $$ CANGIALOSI