000 FXUS64 KMEG 231743 AFDMEG AREA FORECAST DISCUSSION NATIONAL WEATHER SERVICE MEMPHIS TN 1143 AM CST MON NOV 23 2009 .UPDATE... UPDATED FOR 18Z AVIATION DISCUSSION && .PREV DISCUSSION... /ISSUED 1005 AM CST MON NOV 23 2009/ UPDATE... KEPT AREAS OF FOG AND DRIZZLE THROUGH 3 PM AND LOWERED HIGHS A FEW DEGREES TODAY. DISCUSSION... DREARY CONDITIONS WILL PREVAIL TODAY. AT 10 AM ACROSS THE MIDSOUTH AND FORECAST AREA...AREAS OF FOG AND DRIZZLE WERE REDUCING VISIBILITIES TO 3 MILES OR LESS IN MANY LOCATIONS. UNDER CLOUDY SKIES...SURFACE TEMPERATURES RANGED BETWEEN 47 AND 55 DEGREES. LIGHT SOUTH WINDS WERE OCCURRING. REST OF TODAY...AREAS OF FOG AND DRIZZLE WILL SLOWLY DISSIPATE THROUGH THE DAY AS LOW LEVEL MOISTURE BECOMES MORE SHALLOW. TEMPERATURES WILL NOT WARM UP MUCH UNDER CLOUDY SKIES...SO LOWERED HIGHS IN MOST LOCATIONS THINKING THEY WILL ONLY REACH 55 TO 62 DEGREES. GETTING BREAKS IN THE CLOUDS APPEARS UNLIKELY TODAY OR TONIGHT WITH ABUNDANT MOISTURE TAPPED BENEATH A LOW LEVEL INVERSION AROUND 850 MB. ALSO...INCREASED TEMPERATURES TONIGHT A FEW DEGREES THINKING CLOUDS WILL NOT LET TEMPERATURES FALL MUCH. UPDATE HAS BEEN SENT. MBS PREV DISCUSSION... /ISSUED 447 AM CST MON NOV 23 2009/ DISCUSSION... SKIES WILL REMAIN MAINLY OVERCAST ACROSS THE MIDSOUTH THROUGH THE DAY AS LOW LEVEL MOISTURE REMAINS TRAPPED UNDER A STRONG 850 MB INVERSION. THIS COMBINED WITH LIGHT SOUTHERLY SURFACE FLOW WILL KEEP TEMPERATURES ABOUT THE SAME AS YESTERDAY. THE REGION SHOULD REMAIN DRY THROUGH THE DAY. SOME PATCHY FOG IS POSSIBLE MAINLY ALONG THE TENNESSEE RIVER VALLEY LATER THIS EVENING AND THROUGH THE OVERNIGHT HOURS. STRONG H5 TROUGH WILL MAKE ITS PUSH TOWARD THE OHIO VALLEY ON TUESDAY. THE ASSOCIATED SURFACE LOW WILL PUSH TOWARD THE GREAT LAKES AND SWING A COLD FRONT THOUGH THE AREA TUESDAY AFTERNOON. THE FRONT WILL OCCLUDE IN THE VICINITY OF THE MIDSOUTH AND WITH THE LACK OF DECENT FORCING...BELIEVE THE AREA WILL EXPERIENCE ONLY A FEW LIGHT RAIN SHOWERS TUESDAY EVENING. SKIES WILL SLOWLY BEGIN TO CLEAR WEDNESDAY INTO THURSDAY. A MUCH STRONGER H5 SHORTWAVE WILL FOLLOW THE FIRST AND BRING SHARP HEIGHT FALLS INTO THE MIDSOUTH THURSDAY. MODELS DEPICT 850 MB TEMPERATURES IN THE -4C TO -6C RANGE FRIDAY MORNING WHICH WOULD TRANSLATE TO SURFACE TEMPERATURES NEAR THE FREEZING MARK. DRY HIGH PRESSURE FROM THE SOUTHERN PLAINS WILL THEN BUILD INTO THE AREA KEEPING TEMPERATURES BELOW NORMAL THROUGH SATURDAY. SOUTHERLY SURFACE FLOW WILL RETURN SUNDAY AS HIGH PRESSURE SLIDES EAST OF THE AREA. SURFACE LOW PRESSURE WILL THEN SLIDE EAST ACROSS CENTRAL MISSISSIPPI AND ALABAMA BRINGING CHANCES FOR SHOWERS BACK TO THE MIDSOUTH MONDAY INTO TUESDAY. MODELS DIVERGE AT THIS POINT. THE ECMWF BUILDS ANOTHER SURFACE RIDGE INTO THE AREA. THE GFS ON THE OTHER HAND DEPICTS A MUCH STRONGER H5 TROUGH DIGGING DEEP INTO THE SOUTHERN PLAINS AND SLOWING THE SURFACE LOW AND SUBSEQUENT RIDGE DEVELOPMENT. CCD AVIATION... 18Z TAF CYCLE LOW IFR CIGS IN PLACE AT ALL TAF SITES WITH SOME RESTRICTION TO VISIBILITY AND PATCHY DRIZZLE AT KMEM AND KJBR. NO BREAKS IN THE CLOUDS EXPECTED ACROSS ALL OF THE MIDSOUTH AS COOLER AIR REMAINS TRAPPED IN THE LOWEST 040FT AGL. THUS SOMEWHAT CONFIDENT THAT ONLY A SMALL WINDOW OF MVFR CONDITIONS CAN BE EXPECTED MAINLY BETWEEN 21-03Z. THEN CIGS WILL BECOME IFR/LIFR THIS EVENING THROUGH 24/15Z. SOUTH WINDS WILL BE FAIRLY LIGHT OVERNIGHT...BUT INCREASING TO 8-10KTS AFTER 15Z. THIS WILL ALLOW CIGS TO INCREASE MORE RAPIDLY TO MVFR CONDITIONS. IMPROVEMENTS NOT ANTICIPATED TILL AFTER FRONTAL SYSTEM MOVES INTO REGION SHORTLY AFTER 24/18Z. HOWEVER...KJBR WILL SEE VICINITY SHOWERS BEFORE END OF TAF PERIOD. JAB && .PRELIMINARY POINT TEMPS/POPS... MEM 60 53 63 45 / 10 10 50 20 MKL 57 50 61 41 / 10 10 40 20 JBR 59 52 61 40 / 10 10 50 10 TUP 57 51 64 44 / 10 10 20 20 && .MEG WATCHES/WARNINGS/ADVISORIES... AR...NONE. MO...NONE. MS...NONE. TN...NONE. && $$