FXUS63 KJKL 170921 AFDJKL AREA FORECAST DISCUSSION NATIONAL WEATHER SERVICE JACKSON KY 420 AM EST WED NOV 17 2004 .DISCUSSION... A WEAKENED HIGH PRESSURE IS NOW POSITIONED TO OUR SOUTHEAST ALLOWING FOR THE BEGINNING OF RETURN FLOW ACROSS THE REGION. TODAY'S SHORTWAVE IS STARTING OUT A STATE FURTHER WEST THAN YESTERDAY'S S/W AND WILL BE TAKING A BIT MORE NORTH AND EAST ROUTE...NOT BRINGING ITS ASSOCIATED PVA AND LIFT SO CLOSE TO E KY. ELSEWHERE...TEXAS' CLOSE UPPER LOW WILL BEGIN TO FILL AS MOVES NORTHEAST...BRINGING THE AREA DECENT RAIN CHC FOR EARLY FRI. OTHERWISE WE ARE PUT IN PERSISTENT S/W FLOW AS A LONGWAVE WESTERN TROUGH IDLES...DELAYING OUR NEXT COLD SHOT CLOSER TO LATE NEXT WEEK...BUT ALLOWING WEAK WAVES TO RIDE QUICKLY THROUGH THE FLOW. THEREFORE...TODAY...WILL KEEP GOING FORECAST OF SLT TO CHC POPS FOR LIGHT SHOWERS. CURRENT REGIONAL RADAR SHOWS VERY LIGHT SHOWER ACTIVITY ACROSS CENTRAL KY/TN. THIS WILL CONTINUE TO DRIFT SLOWLY EAST BEFORE S/W FOCUSES PRECIP TO OUR NORTHEAST. LOOKING FOR TEMPS TO BE A FEW DEGREES WARMER THAN YESTERDAY WITH WARMER TEMPS STARTING OUT AND H8 WAA. BOTH META/GFS FOCUSING IN ON AN ADDITIONAL SOURCE OF LIFT ACROSS FAR EAST KY...WV/VA...BUT DIDN'T BUY INTO THIS TOO MUCH AS S/W AXIS WILL BE PASSING OR HAVE PASSED THE AREA. PAINTED QPF LINGERS INTO MORNING. NW FLOW THROUGH THE MOIST LAYER EXCEPT AT THE SFC. SO ONLY HAVE CHC POPS ACROSS THE FAR EAST. WARM TEMPS EXPECTED FOR THE NEXT FEW NIGHTS...AND WILL FLIRT WITH THE MAX LOW FOR THE MONTH AT JKL. ALTHOUGH MOS POPS REMAIN FAIRLY HIGH THROUGH THE SHORT/MID RANGES...SEEING NO MAJOR TRIGGERS FOR THE RAIN UNTIL FRI WHEN THE TX WAVE APPROACHES. THAT FEATURE HAS TRENDED A BIT FURTHER WEST. AFTER ITS PASSAGE THOUGH...AREA WILL BE IN WARM SECTOR AND PRECIP CHC GET HARDER TO PINPOINT. THEREFORE WENT DRY THU AND THU EVENING...BRINGING SLT CHC POPS FROM THE WEST TOWARD DAWN FRI. LOOKING INTO THE EXTENDED...SLOWING TREND WITH WESTERN LONGWAVE TROUGH...KEEPING US ON THE WARMER SIDE INTO THE MIDDLE OF NEXT WEEK AND DELAYING THE COLD SHOT UNTIL LATE NEXT WEEK. ONLY CHANGE MADE THIS GO AROUND TO LONG RANGE WAS TO BUMP MAX T UP FOR SAT...BUT MEX NUMBER COMING IN WARMER FOR DAY 6/7. FORECAST PACKAGE ON ITS WAY OUT. && .PREV DISCUSSION... 1110 PM EST TUE NOV 16 2004 CURRENT RADAR SHOWING AREA OF SHOWERS OVER CNTRL KY GRADUALLY WORKING ITS WAY EASTWARD. BOTH THE META AND GFS SHOW A SMALL AREA OF ISENTROPIC LIFT AROUND THE 290K LEVEL...AND SHIFT IT EASTWARD. BOTH MODELS ALSO WEAKEN THIS AREA OF LIFT AS THE NIGHT GOES ON...BUT NOT BEFORE THE AREA REACHES OUR EXTREME WESTERN AND NORTHWESTERN COUNTIES. SO UPDATED TO ADD A SLIGHT CHANCE OF A SHOWER IN THE NORTH AND SOUTHWEST...WITH A CHANCE OF A SPRINKLE ELSEWHERE. TEMPS HAVE BEEN STEADY OR VERY SLOW TO FALL WITH ALL THE CLOUD COVER...AND DEW POINTS HAVE BEEN RISING JUST A TAD. WAS TEMPTED TO RAISE OVERNIGHT LOWS...BUT TEMPS HAVE FINALLY MADE A MOVE DOWNWARD...ESPECIALLY IN THE SOUTHEAST AND EAST WHERE LOWER DEW POINTS HAVE APPARENTLY HELPED THINGS ALONG. CONSIDERING THAT WE ONLY HAVE TO DROP ANOTHER 3 TO 5 DEGREES TO DROP BEFORE BEING IN THE GENERAL BALL PARK...DECIDED TO LEAVE TEMPS AS THEY ARE. HOWEVER...DID WIND UP ADJUSTING TEMP PARAMETERS AND WINDS IN THE ISC GRIDS TO BETTER MATCH UP WITH CURRENT OBS...TRENDS. UPDATED ZONES FOR PRECIP...ALREADY ISSUED. && .PREV DISCUSSION... 455 PM EST TUE NOV 16 2004 S/W AND ASSOCIATED PVA HAS EXITED AND ALL SHOWER/SPRINKLE ACTIVITY HAS CEASED. NEXT PLAYER IS ANOTHER S/W CURRENTLY RIDING OVER THE BACKSIDE OF THE NOW BUCKLED RIDGE IN GREAT LAKES. AFTER EXPERIENCING THE POPS THAT OCCURRED TODAY. HAVE HEADED GUIDANCE BETTER WITH THIS SYSTEM AND HAVE INCLUDED LOW CHANCE POPS...WITH SLIGHTLY HIGHER CHANCES IN THE NORTHEAST...CLOSEST TO WHERE THE BEST FORCING WILL BE. ANOTHER WEAK COLD FRONT WILL FOLLOW WEDNESDAY NIGHT INTO THURSDAY...SO AGAIN HAVE INCLUDED LOW CHANCE POPS TO COVER. MODELS CONTINUE TO CONVERGE ON DEVELOPING A PLAINS LOW. AFOREMENTIONED WEAK FRONTAL BOUNDARY WILL HANG UP NEAR THE OH RIVER LATE THURSDAY...BEFORE DEVELOPING LOW PRESSURE SWINGS THIS NORTH AS A WARM FRONT. MAIN PRECIP OF OUR CONCERN FOR FRIDAY WILL ARRIVE IN THE FORM OF A LEAD S/W. HAVE RAMPED POPS UP TO 40 BETWEEN THIS FEATURE AND GENERAL UPGLIDE FROM SOUTH TO NORTH TOWARDS THE BOUNDARY. EXTENDED...CONTINUED CONSENSUS OF AN AT LEAST PARTIALLY UNSETTLED WEEKEND. MOST LIKELY THERE WILL BE A LULL FRIDAY NIGHT INTO SATURDAY MORNING IN WARM SECTOR AIR MASS OUT AHEAD OF THE APPROACHING COLD FRONT. STILL MAINTAINED 40 POPS LATE AFTERNOON SATURDAY INTO SATURDAY NIGHT...WITH LOWER CHANCE POPS SUNDAY WITH TROUGH AXIS STILL OFF TO THE WEST. OPERATIONAL GFS HAS TRENDED MUCH COLDER FOR THE BEGINNING OF NEXT WEAK...AS DEEPER PREDICTED TROUGH SLINGS IN COLD AIR. WE'LL SEE IF THIS SCENARIO HOLDS. 1147 AM EST TUE NOV 16 2004 SFC...85H AND 50H CHARTS INDICATE THE WEAK TROF THAT TRACKED ACROSS THE PLAINS RIDGE YESTERDAY HAS MIXED WITH THE MOISTURE OVER THE OH RVR VLY TO PRODUCE THE LIGHT RAIN TODAY. SO FAR MOST AREAS OF ERN KY HAVE RECORDED A HUNDREDTH OF AN INCH OR LESS WITH NOT MUCH MORE ACCUMULATION EXPECTED. HEAVIEST RAINFALL WILL BE ACROSS THE NRN COUNTIES...BUT EVEN THERE ACCUMULATIONS WILL AMOUNT TO ONLY A COUPLE OF HUNDREDTHS FOR THE REST OF TODAY. BY LATER THIS AFTERNOON THE RAIN WILL BE MOSTLY OVER BUT THE CLOUD COVER WILL LINGER AND EVEN BECOME LOWER. FOR AVIATION PURPOSES...THE FCST WILL LOWER TO MVFR BY SUNSET AND WILL APPROACH IFR BY DAWN. CLOUDS WILL KEEP TEMPS REPRESSED THIS AFTERNOON BUT WILL ALSO RESTRICT RADIATION TONIGHT. CURRENT FCST HAS THIS WELL IN HAND AND ONLY UPDATE THIS AFTERNOON WILL BE FOR MORNING WORDING AND REFRESH POPS FOR EXPECTED PCPN PATTERN. && .JKL WATCHES/WARNINGS/ADVISORIES...NONE. && $$ OUDEMAN