Area Forecast Discussion
Issued by NWS Jackson, KY

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000 FXUS63 KJKL 281126 AFDJKL AREA FORECAST DISCUSSION NATIONAL WEATHER SERVICE JACKSON KY 726 AM EDT TUE APR 28 2015 .UPDATE... ISSUED AT 726 AM EDT TUE APR 28 2015 THE FORECAST HAS BEEN ON TRACK FOR THE MOST PART OVERNIGHT AND EARLY THIS MORNING. REPORTS OF FOG HAVE BEEN COMING IN THIS MORNING FROM VOLUNTEER WEATHER OBSERVERS...SO THE FOG IN THE GRIDS THROUGH 12Z IS ON THE MONEY. BASED ON TEMPERATURES SEEN IN A NUMBER OF SURFACE OBS...SOME FROST HAS ALSO LIKELY OCCURRED THIS MORNING. THE ZONES SHOULD BE ABLE TO BE UPDATED BY 9 AM TO REMOVE MENTION OF FOG AND FROST. && .SHORT TERM...(TODAY THROUGH WEDNESDAY) ISSUED AT 300 AM EDT TUE APR 28 2015 THE SHORT TERM PORTION OF THE FORECAST WILL START WARM AND DRY...WITH MOSTLY SUNNY SKIES...LIGHT WINDS...AND HIGHS ON THE MID 60S ON TAP FOR TODAY. THESE READINGS WILL BE BELOW NORMAL FOR THIS TIME OF YEAR...BUT STILL A VERY NICE DAY TO BE SURE. OVERNIGHT LOWS WILL BOTTOM OUT IN THE 40S ACROSS THE AREA...AGAIN BELOW NORMAL. EVEN THOUGH IT DOES APPEAR THAT THE WEATHER WILL BE A BIT MORE ACTIVE ON WEDNESDAY...CONFIDENCE IS NOT AS HIGH AS IT COULD BE DUE TO UNCERTAINTY AMONGST THE VARIOUS FORECAST MODELS. THE NAM12...GFS...AND HIRES ARW AND NMM MODELS ARE ALL KEEPING EASTERN KENTUCKY FREE OF PRECIPITATION UNTIL LATE WEDNESDAY NIGHT. THIS IS CONTRAST TO THE ECMWF MODEL AND THE LATEST ENSEMBLE MEANS...WHICH BOTH BRING PRECIPITATION INTO THE AREA LATE TONIGHT INTO EARLY TOMORROW MORNING...AS A SOUTHERN STREAM WEATHER SYSTEM MOVES BY TO OUR SOUTH. THERE IS ALSO SOME DISAGREEMENT AS TO THE TIMING OF A NORTHERN STREAM SYSTEM THAT SOME OF THE MODELS HAVE PHASING WITH THE SOUTHERN SYSTEMS LATE TONIGHT INTO EARLY TOMORROW. ALL THAT BEING SAID...WITH A FEW SETS OF MODEL OUTPUT SHOWING SOME PRECIPITATION GETTING INTO EASTERN KENTUCKY BY AROUND DAWN ON WEDNESDAY...DECIDED TO GO AHEAD AND LEAVE IN PRECIPITATION CHANCES BEGINNING AT 8 OR 9Z ON WEDNESDAY...AND LASTING THROUGH THE END OF THE PERIOD AT 0Z THURSDAY. THE NEW FORECAST WILL FEATURE MUCH LOWER PRECIP CHANCES THAN BEFORE...ALONG WITH A SLOWER NORTHWARD PROGRESSION OF THE PRECIPITATION SHIELD. .LONG TERM...(WEDNESDAY NIGHT THROUGH MONDAY) ISSUED AT 302 AM EDT TUE APR 28 2015 THE MODELS ARE JUST IN FAIR AGREEMENT ALOFT AT THE START OF THE EXTENDED PORTION OF THE FORECAST BUT THEN COME MORE IN LINE WITH EACH OTHER OVER THE WEEKEND. FOR WEDNESDAY NIGHT A RATHER DEEP TROUGH REMAINS IN PLACE OVER THE EASTERN HALF OF THE NATION WITH ITS AXIS PASSING THROUGH KENTUCKY. ANOTHER STRONG REINFORCING SHORTWAVE WILL PUSH SOUTH FROM THE WESTERN GREAT LAKES AND INTO THE BASE OF THE LARGER TROUGH WEDNESDAY NIGHT. THIS WILL LEAD TO A CLOSED LOW TAKING SHAPE OVER THE OHIO VALLEY DURING THE DAY THURSDAY. FOR THIS THE GFS IS STRONGER...BUT FURTHER NORTH THAN THE ECMWF AND THE MIDDLE OF THE ROAD GEM. THE SLOWER AND DEEPER GFS TAKES THIS LOW THROUGH THE CENTRAL AND SOUTHERN APPALACHIANS THURSDAY NIGHT WHILE THE ECMWF IS ALREADY MOVING IT OFFSHORE. BY FRIDAY NIGHT...HEIGHTS WILL BE TICKING UP OVER EASTERN KENTUCKY IN THE WAKE OF THE DEPARTING TROUGH...WITH THE GFS AND GEM MORE IN SYNC THAN THE ECMWF WITH THIS...NOW OFF THE EAST COAST. THIS WILL PLACE EAST KENTUCKY IN THE MIDST OF NORTHWEST FLOW AND WEAK WAVES PASSING BY AT MID LEVELS THROUGH THE FIRST PART OF THE WEEKEND. HIGHER HEIGHTS FOLLOW FOR SUNDAY AND MONDAY AS THE PATTERN FURTHER FLATTENS OUT...WITH BETTER MODEL SUPPORT. THIS IS AHEAD OF A DEVELOPING WAVE MOVING INTO THE SOUTHERN PLAINS AND THEN TO THE MID MISSISSIPPI VALLEY...AS IT GETS PICKED UP BY THE STILL ACTIVE NORTHERN STREAM. A GENERAL MODEL BLEND WILL BE FAVORED TO ACCOUNT FOR THE SPREAD BETWEEN THE GFS AND ECMWF...ESPECIALLY IN THE FIRST PART OF THE LONG TERM FORECAST. SENSIBLE WEATHER WILL FEATURE A DAMP AND COLD START TO THE EXTENDED AS A SFC LOW BENEATH A CLOSED MID LEVEL LOW WILL SLOWLY SLINK THROUGH EASTERN KENTUCKY. DESPITE THE QUICKER MOVEMENT OF THE UPPER SYSTEM IN THE ECMWF...AND ITS STRONGER...COASTAL SFC LOW...IT KEEPS THE QPF AND LOW LEVEL RH MORE ROBUST OVER THIS AREA THROUGH THE DAY THURSDAY AND INTO EARLY FRIDAY WHEN COMPARED TO THE GFS. AT THIS POINT PREFER THE WETTER SOLUTION. MODERATING HIGH PRESSURE BENEATH INCREASING HEIGHTS SHOULD KEEP THE WEATHER QUIET AND WARMER THROUGH THE WEEKEND BEFORE A COLD FRONT APPROACHING FROM THE NORTHWEST SLOWS AND SETTLES NEAR THE OHIO RIVER ON MONDAY... SETTING UP CLOSER TO OUR CWA IN THE GFS THAN THE ECMWF. THIS BOUNDARY WILL NEED TO BE WATCHED FOR THE POTENTIAL OF EXCESSIVE RAINS WELL INTO NEXT WEEK... DEPENDING ON EXACTLY WHERE IT PARKS ITSELF. THE CR GRID BLEND CAME IN REASONABLY WELL WITH SOME ADJUSTMENTS MADE TO LOWER POPS THROUGH THE WEEKEND...AS WELL AS FOR SOME MINOR TERRAIN BASED TEMPERATURE ADJUSTMENTS EACH NIGHT FROM FRIDAY THROUGH SUNDAY. && .AVIATION...(FOR THE 12Z TAFS THROUGH 12Z WEDNESDAY MORNING) ISSUED AT 726 AM EDT TUE APR 28 2015 MOSTLY CLEAR SKIES...LIGHT WINDS...AND VFR CONDITIONS ARE EXPECTED AT THE TAF SITES THROUGH THE END OF THE TAF PERIOD AS HIGH PRESSURE REMAINS IN CONTROL OF AREA WEATHER. && .JKL WATCHES/WARNINGS/ADVISORIES... NONE. && $$ UPDATE...AR SHORT TERM...AR LONG TERM...GREIF AVIATION...AR

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