Area Forecast Discussion
Issued by NWS Jackson, KY

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FXUS63 KJKL 070135
AFDJKL

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE JACKSON KY
935 PM EDT MON JUL 6 2015

.UPDATE...
ISSUED AT 935 PM EDT MON JUL 6 2015

A NEW SET OF ZONES WAS JUST SENT OUT. THE FORECAST GRIDS AND
FORECAST UPDATE WITH BOTH REFLECT THE REMOVAL OF PRECIPITATION
FROM THE OVERNIGHT PERIOD. THE LATEST MODEL DATA STILL DOES NOT
SUPPORT PRECIP FORMING OVERNIGHT AND THERE IS NOTHING DEVELOPING
ANYWHERE DOWNSTREAM THAT WOULD MAKE IT INTO EASTERN KENTUCKY
OVERNIGHT EITHER. ANY STALE WORDING IN THE PREVIOUS FORECAST TEXT
PRODUCE WAS ALSO REMOVED. A NEW HAZARDOUS WEATHER OUTLOOK WILL
ALSO BE ISSUED MOMENTARILY THAT MENTIONS ONLY PATCHY DENSE FOG FOR
LATER TONIGHT AND TO CORRECT A TYPO.

UPDATE ISSUED AT 755 PM EDT MON JUL 6 2015

JUST FINISHED INGESTING THE LATEST OBS DATA INTO THE FORECAST
GRIDS TO ESTABLISH NEW TRENDS. NO MAJOR CHANGES TO THE FORECAST
REQUIRED AT THIS TIME. TOWARD THE END OF THE SHIFT WILL BE
CONSIDERING REMOVING PRECIPITATION FROM THE TONIGHT PERIOD OF THE
FORECAST...AS THE LATEST SHORT TERM MODELS SIMPLY DO NOT SUPPORT
IT DUE TO LACK OF ANY TRIGGERING MECHANISM.

&&

.SHORT TERM...(THIS EVENING THROUGH TUESDAY NIGHT)
ISSUED AT 350 PM EDT MON JUL 6 2015

THE MID AND UPPER LEVEL LOW PRESSURE SYSTEM CONTINUES TO DEPART TO
THE NORTHEAST OF THE REGION THIS AFTERNOON. A WEAK MID LEVEL RIDGE
IS BUILDING TOWARD THE REGION IN BETWEEN THIS DEPARTING SYSTEM AND
A TROUGH MOVING ACROSS THE PLAINS STATES AND APPROACHING THE GREAT
LAKES AND MS VALLEY. THERE HAVE BEEN A FEW SHOWERS ON THE OUTER
EDGE OF THE DEPARTING LOW...AND OVER THE CUMBERLAND PLATEAU...BUT
OVERALL MUCH LESS COVERAGE COMPARED TO 24 HOURS AGO.

A MID LEVEL RIDGE WILL BRIEFLY WORK EAST ACROSS THE COMMONWEALTH
THIS EVENING INTO THE OVERNIGHT...WITH THE AXIS OF THIS RIDGE
MOVING EAST BY DAWN. THIS WILL ALLOW FOR THE NEXT SHORTWAVE TO
BEGIN TO APPROACH THE REGION WITH THE CORRESPONDING COLD FRONT
ALSO ENTERING THE OH VALLEY REGION. THIS SYSTEM SHOULD BE A FOCUS
FOR CONVECTION MAINLY FROM TUE AFTERNOON INTO TUE EVENING AS
DAYTIME HEATING AND A MOIST AIRMASS WILL BE IN PLACE ALONG AND
AHEAD OF THE BOUNDARY. THE BEST DYNAMICS AND SHEAR HOWEVER SHOULD
RESIDE GENERALLY NORTH OF THE REGION...BUT WEAK SHORTWAVES IN SW
FLOW ALOFT WILL BRING A THREAT FOR CONVECTION THROUGH THE END OF
THE PERIOD.

COVERAGE OF CONVECTION SHOULD BE GREATEST ON TUE AFTERNOON AND TUE
EVENING. THE BEST COMBINATION OF THE SHEAR AND INSTABILITY SHOULD
BE ACROSS THE NW PART OF THE CWA...OR IN THE SPC MARGINAL CONVECTIVE
RISK FOR DAY 2. A COUPLE OF STORMS COULD PRODUCE STRONG WINDS
GUSTS. HOWEVER...GIVEN THE RECENT WET PERIOD...THE POTENTIAL FOR
THE FRONT TO STALL OR SLOW DOWN AND GENERALLY BE ALIGNED PARALLEL
TO THE UPPER LEVEL FLOW AND STORMS NOT EXPECTED TO MOVE ALL THAT
SWIFTLY...FLASH FLOODING COULD AGAIN BECOME A CONCERN BY THE END
OF THE PERIOD OR INTO THE LONG TERM PERIOD. PW IS NOT EXPECTED TO
BE SUSTAINED INORDINATELY HIGH...BUT THE POTENTIAL FOR TRAINING OR
REPEATED ROUNDS APPEARS TO BE THERE.

AFTER ANY LINGERING SHOWERS DISSIPATE BY EARLY EVENING...THE
DRIEST PART OF THE PERIOD WILL BE TONIGHT. MOST CONVECTION SHOULD
HOLD OFF UNTIL THE DAYTIME PERIOD LATE TONIGHT...BUT STRAY
CONVECTION CANNOT BE RULED OUT IN THE WARM SECTOR TOWARD DAWN.
OUTSIDE OF CONVECTION...VALLEY FOG...DENSE IS EXPECTED WITH THE
WET GROUND IN PLACE FORM RECENT RAINFALL. THE HIGHEST POPS WERE
USED IN THE NORTH...LIKELY WITH SCATTERED POPS IN THE SOUTH.

.LONG TERM...(WEDNESDAY THROUGH MONDAY)
ISSUED AT 340 PM EDT MON JUL 6 2015

MODELS ARE IN DECENT AGREEMENT WITH THE OVERALL UPPER LEVEL
PATTERN AS WE MOVE INTO THE LONG TERM PORTION OF THE FORECAST. THE
TROUGHING ACROSS THE EASTERN CONUS BREAKS DOWN AND LEADS TO
FAIRLY ZONAL FLOW ACROSS MUCH OF THE OHIO VALLEY INITIALLY...WHILE
TROUGH BUILDS ACROSS THE WESTERN CONUS. THROUGH THE PERIOD SUB
TROPICAL RIDGE BUILDS ACROSS THE SOUTHEASTERN CONUS SENDING MEAN
FLOW NORTH OF EASTERN KENTUCKY. THEN THIS UPPER LEVEL RIDGE BEGINS
TO SHIFT WEST AT THE END OF THE PERIOD AND WE GET BACK INTO A
STORMIER NW FLOW.

OVERALL SURFACE FEATURES LEAD TO A BIT LESS AGREEMENT FROM THE
GUIDANCE SUITES. THIS IS DUE TO THE SURFACE BOUNDARY ACROSS THE
OHIO VALLEY AND THE INTERACTION WITH BUILDING UPPER LEVEL RIDGE
ACROSS THE SOUTHEASTERN CONUS. MOST MODELS BESIDE THE OPERATIONAL
ECMWF KEEP THIS BOUNDARY NORTH OF EASTERN KENTUCKY GENERALLY
DRAPED ALONG THE OHIO RIVER REGION...WITH THE OUTLIER ECMWF
ALLOWING A BIT MORE SOUTHWARD PROGRESSION. GIVEN THE BUILDING
RIDGE THIS MORE SOUTHERN SOLUTION SEEMS TO BE LESS LIKELY BUT
WOULD TEND TO LEAN TOWARD A CONSENSUS BLEND APPROACH AT THIS
POINT. THIS WOULD LEAD TO BETTER CHANCES OF POPS ACROSS THE
NORTHERN PORTIONS OF EASTERN KENTUCKY...WHILE SLIGHT CHANCES WOULD
BE POSSIBLE ACROSS THE SOUTHERN HALF OF THE REGION. ONE THING TO
KEEP IN MIND IS OVERALL STEERING FLOW BECOMES QUIET WEAK ONCE THE
RIDGING BUILDS NORTH. THIS WILL LEAD TO POTENTIAL OF SLOW MOVING
STORMS AND LOCALLY HEAVY RAINFALL. THIS IS INDICATED WITH SOME
MODEL SOUNDING SUGGESTING PWATS NEAR THE 2.00 INCH MARK AND SLOWER
MEAN WINDS. WHILE TOWARD THE END OF THE LONG TERM THIS RIDGE
SHIFTS WEST ACROSS THE PLAINS LEADING TO BETTER CHANCES OF STORMS
IN THE EAST...WITH INCREASED POTENTIAL FOR SURFACE LOW/FRONTS AND
MCS/S MOVING SOUTHEAST INTO THE REGION.

GIVEN SUB TROPICAL/THERMAL RIDGE BUILDING ACROSS THE REGION EXPECT
OVERALL TEMPERATURES TO CLIMB TO NEAR AND ABOVE NORMAL THROUGH THE
PERIOD. THIS IS ALSO BACKED UP BY THE 6 TO 10 DAY FORECAST FROM
THE CPC.

&&

.AVIATION...(FOR THE 00Z TAFS THROUGH 00Z TUESDAY EVENING)
ISSUED AT 755 PM EDT MON JUL 6 2015

VFR CONDITIONS EXPECTED AT THE TAF SITES THROUGH AROUND 9Z
TONIGHT. WILL LIKELY SEE FOG IN OUR VALLEY LOCATIONS
OVERNIGHT...AND AT THE TAF SITES AS WELL. DUE TO THE AMOUNT OF
RAIN THAT HAS FALLEN AT SME AND LOZ OVER THE PAST SEVERAL
DAYS...COULD SEE PERIODS OF IFR OR PERHAPS LIFR CONDITIONS AT
THOSE TWO AIRPORTS. SJS...JKL...AND SYM...HAVING RECEIVED MUCH
LESS RAINFALL RECENTLY THAN LOZ AND SME...SHOULD ONLY EXPERIENCE
MVFR CONDITIONS DUE TO FOG OVERNIGHT. THE FIRST SHOWERS AND STORMS
OF THE DAY THAT MAY MOVE WITHIN THE VICINITY OF THE TAF SITES ARE
EXPECTED TO BEGIN MOVING ACROSS THE AREA AROUND 16Z TUESDAY.


&&

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

$$

UPDATE...AR
SHORT TERM...JP
LONG TERM...DJ
AVIATION...AR



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