000 FXUS64 KJAN 252227 AFDJAN AREA FORECAST DISCUSSION NATIONAL WEATHER SERVICE JACKSON MS 400 PM CST MON FEB 25 2008 .DISCUSSION...A MUCH MORE PLEASANT AND MILD AFTERNOON HAS BEEN ENJOYED BY ALL ACROSS THE ARKLAMISS TODAY. INCREASING SOUTHERLY FLOW DEVELOPING AHEAD OF A POTENT STORM SYSTEM HAS SCOURED OUT THE MOIST INVERSIONS JUST ABOVE GROUND THAT HAVE BEEN THE CAUSE OF THE COOL AND CLOUDY CONDITIONS AROUND THE ARKLAMISS THE PAST FEW DAYS. LATEST SATELLITE IMAGERY SHOWS THAT THIS SOUTHERLY FLOW HAS TAPPED INTO A GULF MOISTURE FEED THIS AFTERNOON WITH LOWER STRATUS CLOUDS JUST OFF TO OUR SOUTHWEST RIGHT NOW INDICATIVE OF A MODIFIED MARITIME GULF AIR MASS BEING BROUGHT INLAND. SOME MODELS YESTERDAY PROGGED RATHER STRONG MOISTURE RETURN (AS IS NOW BEING OBSERVED). THIS DEVELOPMENT DEFINITELY INCREASES THE CHANCES FOR ACTIVE WEATHER ACROSS PORTIONS OF THE LOWER MISSISSIPPI VALLEY LATE TONIGHT AS THE MENTIONED POTENT UPPER LEVEL DISTURBANCE PUSHES EAST FROM THE PLAINS. LATEST THINKING IS THAT UPPER LEVEL DYNAMICS, ATMOSPHERIC FORCING, AND WIND SHEAR ASSOCIATED WITH THIS SYSTEM WILL BE MORE THAN SUFFICIENT FOR THE PRODUCTION OF SEVERE STORMS. HOWEVER...THERMAL CAPPING AND QUESTION MARKS ABOUT INSTABILITY ARE THE BIG DETRIMENTS TO SEVERE WEATHER PRODUCTION. CONS FOR SEVERE WEATHER STAND THE HIGHEST CHANCE OF BEING NEGATED IN FAR NORTHWEST AND WESTERN ZONES THIS EVENING WHERE ANY STORMS WILL HAVE THE POTENTIAL FOR HAIL...HIGH WINDS...AND EVEN TORNADOES. LATER IN THE NIGHT LOW LEVEL INSTABILITY SHOULD DECREASE AS ACTIVITY MOVES FURTHER EAST INTO SOMEWHAT COOLER TEMPERATURES AT THE SURFACE. SEVERE WEATHER IS STILL POSSIBLE ALL THE WAY EAST THROUGH NORTHEAST AND SOUTH-CENTRAL MISSISSIPPI, BUT POTENTIAL REALLY DROPS UP VERY LATE TONIGHT WHEN ACTIVITY APPROACHES FAR SOUTHEAST MISSISSIPPI. NOW IT APPEARS UPPER LEVEL FORCING WILL BE STRONG ENOUGH TO ENSURE ALMOST EVERYONE FROM THE I-20 CORRIDOR NORTHWARD AT LEAST GETS WET...WITH CHANCES OF RECEIVING PRECIP MORE QUESTIONABLE TOWARD THE FAR SOUTH END OF THE FORECAST AREA. A POTENT COLD FRONT MOVING THROUGH THE AREA WILL BE THE BACK EDGE OF THUNDERSTORM POTENTIAL...MOVING OUT OF FAR EASTERN ZONES JUST AFTER DAYBREAK. SOME CLEARING COULD TAKE PLACE AS THE FRONT MOVES OUT...BUT MORE LOW CLOUDS SHOULD MOVE BACK IN LATER IN THE DAY FROM THE NORTH AS STRONG COLD AIR ADVECTION TAKES PLACE. THE BOTTOM EDGE OF A LARGER UPPER LEVEL TROUGH EXPECTED TO PASS ACROSS NORTHERN ZONES SHOULD SQUEEZE OUT A FEW LIGHT SHOWERS OR PATCHES OF DRIZZLE LATER TOMORROW WITH EVEN A FEW INSIGNIFICANT FLURRIES POSSIBLE AROUND THE GOLDEN TRIANGLE TOMORROW NIGHT WHEN COLD AIR FINALLY POURS IN. TOMORROW WILL SPELL THE BEGINNING OF A RATHER CHILLY PERIOD THAT SHOULD LAST THROUGH WEDNESDAY NIGHT AS TEMPERATURES GENERALLY RUN SOME 10 TO 15 DEGREES BELOW NORMAL. MODIFICATION WILL START ON THURSDAY...BUT TRULY MILD WEATHER MAY NOT RETURN AGAIN UNTIL THIS WEEKEND. THE REST OF THE FORECAST HAS BEEN UNCHANGED AND I ATTACHED PORTIONS OF THOSE DISCUSSIONS DEALING WITH LATE IN THE WEEK AND INTO THE WEEKEND: .PREVIOUS DISCUSSION...THE SURFACE HIGH SHIFTS EAST OF THE FORECAST AREA BY SUNRISE THURSDAY AND LIGHT WARM AIR ADVECTION DEVELOPS DURING THE DAY. RAIN CHANCES INCREASE BY THE END OF THE WORK WEEK WHEN MOISTURE INCREASES AHEAD OF AN APPROACHING SURFACE TROUGH. A HEALTHY SHORTWAVE SHIFTS ACROSS THE AREA FRIDAY AFTERNOON. LOWER LAYERS OF THE ATMOSPHERE REMAIN RELATIVELY STABLE SUGGESTING ELEVATED CONVECTION FOR FRI FOR NOW. FORECAST SOUNDINGS ALSO SUGGEST A WEAK CAP FOR MOST OF THE DAY. THE AIR MASS DRIES QUICKLY FRIDAY NIGHT IN THE WAKE OF THE UPPER WAVE. THE SURFACE TROUGH WASHES OUT AS IT DRIFTS SWD. ENSEMBLE MEMBERS SHOW A PRETTY WIDE RANGE FOR POPS INTO SATURDAY. WILL FOLLOW GFS FOR NOW AND LEAVE WEEKEND DRY. WILL SEE BACKING UPPER FLOW AND INCREASING WARM AIR ADVECTION BY SUNDAY AS A NEGATIVELY TILTED WAVE DIGS INTO ERN TX./03/ && .AVIATION...ALL VFR CONDITIONS PREVAIL AT MID AFTERNOON MONDAY...ALTHOUGH MVFR CEILINGS WILL BECOME INCREASING POSSIBLE WEST OF THE I-55 CORRIDOR THROUGH EARLY THIS EVENING AS A STRONG SYSTEM APPROACHES. WILL BRING IN MVFR/IFR CIGS/VIS TO WESTERN SITES WITH CB AHEAD OF FRONT AFTER 03Z...WITH TSRA EAST BY 06-08Z. EXPECT PERIODS OF TSRA OVERNIGHT TO TEMPORARILY DROP CONDITIONS TO LIFR AS FRONT PASSES...BEFORE BREEZY POST-FRONTAL NORTHWEST FLOW ENTERS WEST AFTER 12Z AND CIGS/VIS LIFT TO VFR. /BB/ && .PRELIMINARY POINT TEMPS/POPS... JACKSON 48 52 29 50 / 74 15 6 0 MERIDIAN 51 53 29 51 / 80 35 10 1 VICKSBURG 45 53 31 54 / 67 8 4 0 HATTIESBURG 55 58 31 55 / 58 27 5 0 NATCHEZ 49 54 31 52 / 51 7 3 0 GREENVILLE 41 49 31 51 / 80 10 4 0 GREENWOOD 41 47 30 49 / 93 10 7 0 && .JAN WATCHES/WARNINGS/ADVISORIES... MS...LAKE WIND ADVISORY FROM 6 AM TO 6 PM CST TUESDAY FOR MSZ026>033- 036>039-042>066-072>074. LAKE WIND ADVISORY FROM 4 AM TO 6 PM CST TUESDAY FOR MSZ018-019- 025-034-035-040-041. LA...LAKE WIND ADVISORY FROM 6 AM TO 6 PM CST TUESDAY FOR LAZ023>026. LAKE WIND ADVISORY FROM 4 AM TO 6 PM CST TUESDAY FOR LAZ007>009- 015-016. AR...LAKE WIND ADVISORY FROM 4 AM TO 6 PM CST TUESDAY FOR ARZ074-075. && $$ 50