Area Forecast Discussion
Issued by NWS Jackson, KY

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000
FXUS63 KJKL 020030 AAA
AFDJKL

AREA FORECAST DISCUSSION...UPDATED
NATIONAL WEATHER SERVICE JACKSON KY
830 PM EDT WED JUL 1 2015

.UPDATE...
ISSUED AT 800 PM EDT WED JUL 1 2015

23Z SFC ANALYSIS SHOWS A WAVY FRONTAL BOUNDARY LYING ACROSS
EASTERN KENTUCKY. THIS IS KEEPING THE THREAT OF SHOWERS AND
THUNDERSTORMS GOING THROUGH THE EVENING. IT IS ALSO CONTRIBUTING
TO A SLOW MOVEMENT TO THE STRONGER STORMS AND...WHEN COMBINED
WITH TRAINING AND HIGH PWATS...LOCALIZED FLASH FLOODING IS A
THREAT THROUGH AT LEAST THE EVENING. THE HRRR SUGGESTS THAT THE
CURRENT CONVECTION WILL WANE LATER THIS EVENING BEFORE ANOTHER
WAVE OF LOW PRESSURE AND POTENTIALLY ORGANIZED CONVECTION MOVES
EAST ALONG THE FRONT TO DAMPEN THE START OF THURSDAY. GIVEN THE
MODE OF CONVECTION IN THIS SITUATION IT IS HARD TO BITE TOO HARD
ON ONE SOLUTION SO HAVE BROAD BRUSHED THIS SCENARIO A BIT IN THE
GRIDS FOR LATE TONIGHT...BUT IT DOES SEEM TO MATCH UP PRETTY WELL
WITH THE NEIGHBORS. HAVE ALSO ADDED A TOUCH OF FOG TO THE GRIDS
FOR LATE TONIGHT AND TWEAKED THE NEAR TERM T AND TD GRIDS PER THE
LATEST OBS/TRENDS. THESE HAVE BEEN SENT TO THE NDFD AND WEB
SERVERS ALONG WITH A FRESHENED SET OF ZONES. AN UPDATED HWO
HIGHLIGHTING THE ISOLATED HEAVY RAIN CONCERNS WILL BE ISSUED
SHORTLY.

&&

.SHORT TERM...(THIS EVENING THROUGH THURSDAY NIGHT)
ISSUED AT 347 PM EDT WED JUL 1 2015

FRONTAL ZONE REMAINS STRETCHED ACROSS EASTERN KENTUCKY THIS
AFTERNOON...FROM NEAR PAINTSVILLE...OVER TO STANTON. ACTIVITY HAS
INCREASED ALONG THIS CONVERGENCE ZONE THIS AFTERNOON...BUT LIMITED
INSTABILITY AND SHEAR IS KEEPING EVERYTHING FAIRLY WEAK COMPARED
WITH THE PAST FEW DAYS. OUTFLOW BOUNDARY FROM OVERNIGHT CONVECTION
CONTINUES TO PUSH EAST WITH A BAND OF RAIN AND WILL BE EXITING
EASTERN KENTUCKY OVER THE NEXT 2 TO 4 HOURS.

QUESTION THEN TURNS TO WHAT HAPPENS OVERNIGHT. IT APPEARS WE MAY
SEE MOST OF THE CURRENT ACTIVITY ALONG THE FRONTAL BOUNDARY DIE
OFF AS INSTABILITY DECREASES THIS EVENING. THEN WE WILL TURN
UPSTREAM TO SEE WHAT CONVECTION FIRES OFF OVER THE PLAINS AND
EXACTLY WHERE THIS OCCURS. MODELS REMAIN VARIABLE ON TRACK OF MCS
TONIGHT. GOING TO STAY FAIRLY CLOSE TO PREVIOUS FORECAST AND MAKE
VERY FEW CHANGES GIVEN THE DEGREE OF UNCERTAINTY ON HOW TONIGHT
WILL EVOLVE. ANY MCS WOULD LIKELY BE APPROACHING THE AREA TOWARDS
DAYBREAK...SO HAVE GONE WITH THE HIGHEST POPS LATE TONIGHT.
WHATEVER IS LEFT FROM OVERNIGHT MCS MAY TRACK ACROSS THE AREA ON
THURSDAY...KEEPING THE WEATHER VERY UNSETTLED. A SHORTWAVE TROUGH
WILL PUSH ACROSS THE AREA THURSDAY NIGHT...KEEPING THE THREAT OF
RAIN GOING. DESPITE THE PERSISTENT WET WEATHER...TOO MUCH
UNCERTAINTY ON RAINFALL AMOUNTS TO GO WITH A FLOOD WATCH AT THIS
POINT. WILL JUST MAINTAIN THE MENTION OF LOCALLY HEAVY RAIN IN THE
HWO. PW`S ARE FAIRLY HIGH WITH A STALLED FRONTAL BOUNDARY OVER THE
REGION. THUS...IF WE CAN GET SOME TRAINING STORMS...THEN A BETTER
FLOODING THREAT MAY BE REALIZED.

.LONG TERM...(FRIDAY THROUGH WEDNESDAY)
ISSUED AT 354 PM EDT WED JUL 1 2015

PERIOD BEGINS WITH DECENT AGREEMENT IN THE OVERALL TROUGH STILL
SET UP ACROSS THE EASTERN CONUS AND STRONG RIDGE IN THE WESTERN
CONUS. MODELS ARE DIFFERING IN THE AMPLITUDE OF THE SHORTWAVE
ENERGY DROPPING SE INTO THE REGION. THIS COULD HAVE IMPLICATIONS
ON THE OVERALL SURFACE FEATURES THAT DEVELOP DURING THE FIRST
PORTION OF THE LONG TERM. THEN TOWARD THE END OF THE PERIOD THE
PATTERN LOOKS TO SHIFT FROM LONG WAVE TROUGH TO WEAKER TROUGHING
ACROSS THE EAST WHILE RIDGING BREAKS DOWN IN THE WESTERN US.
MODELS CONTINUE TO VERY IN THIS PERIOD...HOWEVER AGREE WITH A
OVERALL CHANGE IN THE PATTERN.

SURFACE BOUNDARY WILL CONTINUE TO MEANDER ACROSS THE REGION
THROUGH THE FIRST PART OF THE LONG TERM. THERE REMAINS A FAIR
AMOUNT OF VARIABILITY IN EXACT LOCATION OF THE BOUNDARY FROM MODEL
TO MODEL. THIS WILL LEAD TO CONTINUED UNSETTLED CONDITIONS ACROSS
THE REGION. GIVEN THIS QUASI-STATIONARY BOUNDARY AND MULTIPLE
UPPER LEVEL DISTURBANCES WILL LEAD TO POTENTIAL HEAVY RAINFALL
OVER SOME AREAS THROUGH THE PERIOD...HOWEVER A FAIR AMOUNT OF
UNCERTAINTY STILL EXISTS IN EXACT LOCATION OF HEAVIEST QPF.
ANOTHER COLD FRONT APPROACHES DURING THE LATE PORTION OF THE
PERIOD THAT WILL INCREASE POPS SLIGHTLY LATE TUESDAY INTO
WEDNESDAY. GIVEN VARIABILITY IN THE FRONT AND OVERALL PATTERN
CHANGE STUCK CLOSE TO MODEL BLENDS IN THE LONG TERM FORECAST.
OVERALL TEMPERATURES THROUGH THE PERIOD WILL REMAIN NEAR TO BELOW
NORMAL GIVEN THE UNSETTLED PATTERN AND TROUGH.

&&

.AVIATION...(FOR THE 00Z TAFS THROUGH 00Z THURSDAY EVENING)
ISSUED AT 830 PM EDT WED JUL 1 2015

SME AND LOZ WILL LIKELY BE AFFECTED BY THE EVENING STORMS...WHILE
THE REST OF THE TAF SITES WILL SEE VFR CONDITIONS RETURN DURING
THE MID AND LATE EVENING HOURS. HOWEVER...CIGS WILL LIKELY COME
BACK DOWN TONIGHT AS A FRONTAL ZONE REMAINS DRAPED ACROSS EASTERN
KENTUCKY. THUS...EXPECT CLOUDS TO LOWER THROUGH THE NIGHT FALLING
BACK TO AT OR NEAR IFR FOR MOST PLACES BY THE EARLY MORNING HOURS
OF THURSDAY. IT IS ALSO POSSIBLE STRATUS COULD BUILD DOWN ONTO
THE RIDGES...CREATING SOME POCKETS OF DENSE FOG FOR OUR MOUNTAIN
TOP AIRPORTS. UNCERTAINTY REMAINS FOR THE LATTER PART OF THE NIGHT
INTO THURSDAY MORNING WITH RESPECT TO A POTENTIAL FOR RENEWED
CONVECTION FROM AN MCS THAT MAY ORGANIZE UPSTREAM. DEPENDING ON
WHERE THIS FEATURE TRACKS...WE COULD GET MORE RAIN/STORMS LATE
TONIGHT INTO THURSDAY MORNING. HOWEVER...TOO MUCH UNCERTAINTY AT
THIS TIME TO JUMP TO HARD ON THIS IDEA SO FOR NOW HAVE ADDED VCSH
AND VCTS TO THE SOUTHERN TAF SITES FOR LATE TONIGHT THROUGH
THURSDAY MORNING. OUTSIDE OF ANY STORMS...WINDS WILL BE LIGHT...AT
AROUND 5 KTS OR LESS...AND GENERALLY FROM THE SOUTHWEST.

&&

.JKL WATCHES/WARNINGS/ADVISORIES...
NONE.
&&

$$

UPDATE...GREIF
SHORT TERM...KAS
LONG TERM...DJ
AVIATION...GREIF


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