559 FXUS63 KPAH 290048 AFDPAH AREA FORECAST DISCUSSION NATIONAL WEATHER SERVICE PADUCAH KY 648 PM CST MON JAN 28 2013 .UPDATE... ISSUED AT 648 PM CST MON JAN 28 2013 UPDATED THE PUBLIC GRIDS THROUGH DAYBREAK TUESDAY. MAIN ISSUES WERE TO FOCUS LOW CHANCE POPS FOR LIGHT RAIN AND DRIZZLE IN THE KEVV/KOWB AREAS EARLY THIS EVENING...AND THEN KEEP THE ENTIRE AREA DRY LATE EVENING INTO THE OVERNIGHT HOURS. DID KEEP A 20-30 POP IN THE WEST TOWARD 12Z...BUT KEPT THE EAST DRY. THE 18Z NAM...AND THE 12Z HI-RES WRF RUNS KEEP THE AREA DRY THROUGH 12Z...SO GIVEN THE VERY QUIET REGIONAL RADAR MOSAICS...DECIDED TO PUT A BIT MORE EXPLICIT POP TRENDS IN THE FORECAST. ALSO USED THE WRF 2-M TEMPERATURE DATA TO TWEAK TRENDS THROUGH THE NIGHT. SHOULD NOT SEE MUCH IF ANY DROP OFF THROUGH THE NIGHT. RECORD MAX MINIMUMS WILL BE CRUSHED IN MOST LOCATIONS FOR MONDAY. UPDATE ISSUED AT 630 PM CST MON JAN 28 2013 UPDATED AVIATION DISCUSSION ONLY. && .SHORT TERM /TONIGHT THROUGH WEDNESDAY NIGHT/... ISSUED AT 335 PM CST MON JAN 28 2013 MAIN FEATURE OF INTEREST CONTINUES TO BE A LOW PRESSURE CENTER THAT WILL TAKE SHAPE OVER NORTHERN MISSOURI TUESDAY AFTERNOON...THEN DEEPEN QUICKLY AS IT MOVES NORTHEAST INTO MICHIGAN BY WED MORNING. A COLD FRONT WILL STRENGTHEN AS IT SWEEPS EASTWARD...PASSING ACROSS THE LOWER OHIO VALLEY BY 12Z WED. STRONG LOW LEVEL SOUTHWEST FLOW HAS ALREADY BECOME ESTABLISHED...WITH THE SURFACE DEW POINT ALREADY AT 60 DEGREES AT KPOF AS OF 19Z. THE LOW LEVEL JET WILL STRENGTHEN FURTHER TO BETWEEN 70 AND 80 KNOTS TUESDAY EVENING. THE TREMENDOUS AMOUNT OF SHEAR /BOTH LOW LEVEL AND DEEP LAYER/ WARRANTS CONCERN DUE TO THE POTENTIAL FOR CONVECTIVE UPDRAFTS. AS FAR AS INSTABILITY...THE GENERAL MODEL CONSENSUS IS REFLECTED IN THE 12Z GFS...WHICH SHOWS 100 TO 300 J/KG OF SURFACE BASED CAPE TUESDAY NIGHT. MUCAPES ARE SIMILAR. SPC DAY 2 OUTLOOK CONTAINS MORE DETAILS. THOUGH THE SHEAR/INSTABILITY COMBO WILL BE MORE FAVORABLE FOR SEVERE FURTHER SOUTH ACROSS ARKANSAS/TENNESSEE...THERE IS AT LEAST A LOW POTENTIAL FOR ISOLATED TORNADOES IN OUR AREA. THE OTHER AREA OF CONCERN IS HEAVY RAIN POTENTIAL...BUT THIS HAS DIMINISHED JUST A LITTLE BASED ON 12Z GUIDANCE. 12Z NAM/GFS QPF... ALONG WITH HPC QPF...ALL POINT TO LESS QPF THAN ORIGINALLY ANTICIPATED. THIS COULD BE DUE TO THE DELAYED ARRIVAL OF PRECIP. WILL LOWER POPS FOR TONIGHT AND TUESDAY AS THE TIMING HAS SLOWED DOWN SOMEWHAT. THE FRONT WILL ACCELERATE EASTWARD TUESDAY NIGHT ALONG WITH THE PRE FRONTAL CONVERGENCE ZONE. THIS SHOULD LIMIT QPF TO THE 1 TO 2 INCH RANGE...THOUGH ISOLATED HIGHER AMOUNTS ARE LIKELY. GRADIENT WINDS WOULD BE A SIGNIFICANT PROBLEM TUESDAY AFTERNOON AND EVENING IF LOW LEVEL LAPSE RATES STEEPEN UNEXPECTEDLY. HOWEVER...GFS THERMAL PROFILES CONTINUE TO INDICATE POOR MIXING POTENTIAL BENEATH THE LOW LEVEL JET. IN THE WAKE OF THE COLD FRONT...TEMPS WILL FALL SLOWLY THROUGH THE 40S ON WEDNESDAY. SOME LINGERING LIGHT RAIN IS POSSIBLE...MAINLY IN THE MORNING. GUSTY WINDS WILL CONTINUE. PARTIAL CLEARING AND COLDER CONDITIONS ARE EXPECTED ON WEDNESDAY NIGHT AS A STRONG 1038 MB HIGH BUILDS SOUTHEAST ACROSS THE NORTHERN PLAINS. .LONG TERM /THURSDAY THROUGH MONDAY NIGHT/... ISSUED AT 345 PM CST MON JAN 28 2013 A MOISTURE STARVED SECONDARY COLD FRONT WILL MOVE THROUGH THE QUAD STATE REGION THURSDAY AFTERNOON AND EVENING. MOST OF THE MODELS DO NOT GENERATE ENOUGH LIFT OR MOISTURE FOR MUCH IN THE WAY OF PRECIP UNTIL THE FRONT CLEARS THE AREA. HOWEVER...WILL LEAVE A SMALL MENTION OF SOME VERY LIGHT SNOW OVER NWRN KY AND SW IN JUST IN CASE. SHOULD BE LITTLE TO NO IMPACTS THO... A RATHER IMPRESSIVE BUT SHORT LIVED COLD BLAST WILL OCCUR ON THURSDAY NIGHT AND FRIDAY...AS 850 MB TEMPS FALL TO BETWEEN MINUS 8 AND MINUS 15...DEPENDING ON MODEL OF CHOICE. SURFACE HIGHS ARE LIKELY TO REMAIN MAINLY IN THE 20S AND 30S ON FRIDAY...EVEN WITH FULL SUN. MORNING LOWS WILL BEGIN IN THE 15 TO 25 DEGREE RANGE FOR THE MOST PART. RETURN FLOW OF MILDER AIR WILL OCCUR ON FRIDAY NIGHT...BEFORE A RELATIVELY WEAK COLD FRONT PASSES ON SATURDAY. THIS MAY BRING SOME SCT LIGHT RAINS TO S AREAS...WITH LIGHT RAIN OR SNOW POSSIBLE FARTHER N/E...ESP SW IN AND THE NRN PENNYRILE OF WRN KY. THE DRIER AIR FOLLOWING THIS SYSTEM SUNDAY WILL NOT BE OF CANADIAN ORIGIN...HENCE NOT NEARLY AS COLD AS THE THU/FRI AIR. && .AVIATION...(FOR THE 00Z TAFS THROUGH 00Z TUESDAY EVENING) ISSUED AT 630 PM CST MON JAN 28 2013 SRLY SFC WINDS AT THE SFC WILL REMAIN UP THROUGH THE TAF PERIOD... GUSTING ABOVE 20 KTS DURING THE DAYLIGHT HOURS. IT IS POSSIBLE THAT SERN MO MAY HAVE GUSTS ABOVE 30 KTS IN THE LATE AFTERNOON JUST AHEAD OF A FORECAST LINE OF SHOWERS/TSTMS. VFR/MVFR CIGS ACROSS THE REGION MAY IMPROVE EVEN MORE THROUGH MOST OF THE EVENING...BUT AT THIS TIME...IFR CIGS ARE POSSIBLE STARTING AROUND THE MIDNIGHT HOUR IN ROUGHLY THE WRN HALF OF THE REGION. DATA IS SHOWING THAT CIGS DURING THE DAY TUE MAY GO COMPLETELY VFR AS THE FLOW ALOFT SCREAMS OUT OF THE SW. ALL THIS WILL BE REVIEWED CAREFULLY FOR THE 06Z TAFS. && .PAH WATCHES/WARNINGS/ADVISORIES... IL...NONE. MO...NONE. IN...NONE. KY...NONE. && $$ UPDATE...DRS SHORT TERM...MY LONG TERM...GM AVIATION...DB