FXUS63 KJKL 140118 AFDJKL AREA FORECAST DISCUSSION NATIONAL WEATHER SERVICE JACKSON KY 917 PM EDT FRI AUG 13 2004 .DISCUSSION... SKIES ACROSS THE AREA ARE CLOUDY RATHER THAN PARTLY CLOUDY THIS EVENING...FROM ALTO CU WHICH SPREAD OUT AT THE TOP OF MIXED LAYER AFTER CU DEVELOPMENT DURING THE DAY. MODELS DO NOT SEEM TO HAVE HANDLED THE ALTO CU VERY WELL...AND THEIR DISSIPATION IS A BIT PROBLEMATIC. MODELS DO INDICATE A DRYING TREND ALOFT...AND WITH A LACK OF CONVECTION TO FEED THE ALTO CU THEY SHOULD CONTINUE TO DRY UP...AS EVIDENCED BY EROSION FROM THE EDGES ON SATELLITE IMAGERY. IT SEEMS TO BE A QUESTION OF HOW QUICKLY IT HAPPENS. IF IT HAPPENS TOO SLOWLY...OUR FORECAST LOWS COULD BE IN JEOPARDY OF NOT BEING REACHED...BUT FOR NOW HAVE OPTED TO LET THE TEMP FORECAST STAND. HAVE ALSO LOWERED WIND SPEEDS FOR SOME PERIODS IN OUR SOUTHEAST COUNTIES. ZFP ALREADY SENT...AND OTHER PRODUCTS WILL FOLLOW. && .PREV DISCUSSIONS... 520 PM EDT FRI AUG 13 2004 20Z SFC ANALYSIS SHOWS COOL HIGH PRESSURE THROUGH THE MIDWEST AND INTO THE OHIO VALLEY WITH A STALLED FRONTAL BOUNDARY EAST OF THE APPALACHIANS...FUNNELING THE TROPICAL MOISTURE AND STORMS UP THE EAST COAST. EARLIER AREAS OF FOG AND LOW CLOUDS BROKE UP ONLY TO BE REPLACED WITH A LARGE AMOUNT OF CU. THESE CLOUDS AND CONTINUED CAA FROM THE NORTHWEST HAVE KEPT TEMPERATURES FROM CLIMBING OUT OF THE 60S OVER MOST LOCATIONS OF EAST KENTUCKY...SETTING RECORD COOL MAXIMUM TEMPERATURES FOR THE DATE. THE MODELS ARE IN DECENT AGREEMENT ALOFT AS THE OHIO VALLEY TROUGH ONLY SLOWLY WORKS THROUGH THE AREA DURING THE WEEKEND. A COUPLE OF SHORTWAVES WILL HELP TO MAINTAIN THIS TROUGH...WITH THE MAIN STRONG WAVE DIGGING THROUGH THE BASE OF IT SUNDAY MORNING. FOLLOWING THE WEEKEND THE TROUGH WILL DEAMPLIFY SOMEWHAT OVER THE OHIO VALLEY AS ITS PARENT LOW...THE POLAR VORTEX RESIDING OVER THE HUDSON BAY... RECONSOLIDATES AND SEEPS DOWN INTO SOUTH CENTRAL CANADA TOWARD THE NORTHERN PLAINS STATES BY MIDWEEK. THE EXTENDED FORECAST CALLS FOR THIS STRONG GYRE TO SLOWLY SPIN JUST TO THE NORTH OF THE GREAT LAKES ...DOMINATING THE CENTRAL PART OF THE CONTINENT WITH IN A FALL-LIKE PATTERN. SENSIBLE WEATHER WILL FEATURE ANOTHER COOL AND PLEASANT WEEKEND FOR THIS PART OF AUGUST. UNDER THE INCREASING INFLUENCE OF HIGH PRESSURE ...CLEARING SKIES...GOOD RADIATIONAL COOLING AND PLENTY OF LOW LEVEL MOISTURE WILL MAKE FOR MORE FOG TONIGHT. ANOTHER COOL DAY IS EXPECTED SATURDAY WITH SUNSHINE SELF DESTRUCTING SOMEWHAT AS THE CU DEVELOPS. THIS COOL PATTERN WILL CONTINUE ON SUNDAY WITH A BIT MORE CLOUDS EXPECTED AS THE UPPER LEVEL SHORTWAVE SHIFTS THROUGH THE OHIO VALLEY. MONDAY AND TUESDAY WILL SEE TEMPERATURES MODERATE BACK CLOSER TO NORMAL AS THE HIGH WEAKENS AND SHIFTS EAST. THERE WILL BE A RETURN OF A SMALL CHANCE OF SHOWERS AND THUNDERSTORMS FROM WEDNESDAY THROUGH FRIDAY AS A LOW ANGLE FRONT SLOWLY DRIFTS THROUGH KENTUCKY TO END THE WORK WEEK. MOS TEMPERATURES ARE SIMILARLY QUITE COOL TONIGHT WITH NEAR RECORD LOWS AGAIN PREDICTED. WILL NOT STRAY FAR AS THE CU WILL BREAK UP THIS EVENING WITH MOSTLY CLEAR SKIES. WILL ALSO UNDERCUT HIGHS SATURDAY DUE TO CONTINUED CAA AND COLD AIR CU. SATURDAY NIGHT/S LOWS WERE CLOSE IN THE FWC AND MAV...BUT A TAD WARM IN THE MET. WENT WITH THE COOLER NUMBERS AND INCLUDED A BIT OF A RIDGE TO VALLEY SPLIT. A BLEND OF TEMPERATURES LOOKED BEST FOR SUNDAY. WAS NOT TOO IMPRESSED WITH THE POP CHANCES THROUGH THE WEEKEND...SO UNDERCUT THE MOS POPS A BIT...ESPECIALLY THOSE FROM THE FWC. AS FOR IFPS GRIDS...RAN MY USUAL PROCEDURE TO POPULATE THE TEMPERATURES...DEWPOINTS AND WINDS FROM THE MESOETA THROUGH 60 HOURS. AGAIN HAD TO TAKE THESE TEMPS DOWN IN THE NEAR TERM. ALSO FINE TUNED THE MINS AT THE CCF POINTS TONIGHT. TOOK THE GRID DOWN A COUPLE OF DEGREES FOR SATURDAY AND OPENED UP A BIGGER HILL TO VALLEY TEMP SPLIT FOR SUNDAY MORNING LOWS. HAD TO MAKE ONLY MINOR ADJUSTMENTS TO THE WIND GRIDS THROUGH 60 HOURS. THE REST OF THE GRIDS WHERE IN DECENT SHAPE WITH JUST SOME SMALL TWEAKS MADE TO THE SKY AND POP GRIDS THROUGH MIDWEEK. 1000 AM EDT FRI AUG 13 2004 UPDATE THIS MORNING TO LOWER TEMPS, INCREASE SKY COVER, AND REFRESH FOR MORNING FOG/POPS WORDING. LIGHT CAA TO CONTINUE TODAY AS WE ARE UNDER THE INFLUENCE OF COOL NW FLOW. EXPECT CLEAR SLIVER IN SKY COVER TO FILL IN BY AFTERNOON YIELDING A MOSTLY CLOUDY SKY. EVEN THOUGH IT IS AUG, TEMPS WILL STRUGGLE TO EVEN REACH THE 70 DEGREE MARK. BROUGHT TEMPS DOWN INTO THE UPPER 60S FOR HIGHS. FULL UPDATE PACKAGE OUT SOON. 303 AM EDT FRI AUG 13 2004 MAIN CONCERN TO EXAMINE FOR THIS FORECAST WAS THE CHANCE OF PRECIP ASSOCIATED WITH UNUSUAL HIGH AMPLITUDE TROF ACROSS THE EASTERN 2/3RD OF THE USA...AND WITH THE POTENTIAL INFLUENCE OF CHARLEY. GENERALLY FOLLOWED THE GFS SOLUTION THIS FORECAST CYCLE WITH ITS HANDLING OF CHARLEY. AS FOR TODAY...LAPS SOUNDINGS SHOW DRIER AIR HAS BEEN ADVECTING INTO OUR AREA OVER THE PAST SEVERAL HOURS...WITH THE BEST MOISTURE PROFILE IN THE FAR EAST (PIKE CO.). AS A RESULT...KEPT A CHANCE OF RAIN FOR THE EXTREME EASTERN PORTION OF THE FORECAST AREA EARLY...BEFORE UPPER WAVE EXITS KY BEFORE 18Z. OTHERWISE...WITH WEAK CAA TODAY TEMPS WILL ONCE AGAIN BE WELL BLO NORMAL WITH TEMPERATURES REACHING ONLY THE LOWER 70S. DAILY MINIMUM HIGH TEMP RECORD OF 74 TODAY AT JKL MAY BE BROKEN. IN ADVANCE OF CHARLEY MOVING UP TROUGH GA/SC SATURDAY...LOW LEVEL FLOW BACKS AND ETA DEVELOPS AN AREA OF ISENTROPIC LIFT SATURDAY AND SATURDAY NIGHT. AS A RESULT...IT CREATES AN AREA OF LIGHT PCPN ACROSS SE KY. HOWEVER...HISTORICALLY REMNANTS OF TROPIC SYSTEMS THAT TRACK EAST OF THE APPALACHIANS USUALLY ARE NOT FAVORABLE FOR PRODUCING PCPN IN OUR AREA. THUS...WILL FOLLOW THE GFS SOLUTION OF KEEPING BEST LIFT EAST OF OUR FORECAST AREA AND CONTINUE DRY FORECAST. UPPER TROF AND ASSOCIATED MID LEVEL COLD POOL BEGINS TO LIFT ON SUNDAY AND AS IT SWINGS TO THE NORTH OF OUR AREA IT MAY PRODUCE SCT SHRA/TSRA...ESPECIALLY IF STRONGER GFS SOLUTION PREVAILS. EVEN ETA FORECAST SOUNDINGS PRODUCE AREA OF CAPES IN EXCESS OF 400 J/KG...SO CAN'T RULE OUT SOME WIDELY SCATTERED SHRA/TSRA SUNDAY AFTERNOON AND INTRODUCED THIS SLIGHT CHANCE TO THE FORECAST FOR SUNDAY FOR THE NORTHERN HALF OF THE FORECAST AREA. && .JKL WATCHES/WARNINGS/ADVISORIES...NONE. && $$ HAL