Area Forecast Discussion
Issued by NWS Jackson, KY

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000
FXUS63 KJKL 270352
AFDJKL

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE JACKSON KY
1152 PM EDT SAT JUL 26 2014

.UPDATE...
ISSUED AT 1151 PM EDT SAT JUL 26 2014

THE MCS IS WEAKENING TO THE WEST OVER CENTRAL KENTUCKY. IN DISCUSSION
WITH SPC...DECIDED NOT TO EXTEND THE WATCH INTO EASTERN KENTUCKY AS
THE STORMS ARE SHOWING A WEAKENING TREND. THERE ARE TWO STORMS WE
ARE WATCHING. ONE IS THE STORM MOVING INTO CASEY COUNTY AND THE
OTHER ONE IS OVER OWEN COUNTY. EXPECT THE LINE OF SHOWERS TO MOVE
ACROSS THE EASTERN KENTUCKY DURING THE OVERNIGHT HOURS. THERE IS
STILL A REMOTE POSSIBILITY OF GETTING A STORM CAPABLE OF PRODUCING
WIND DAMAGE...BUT THEY SHOULD BE FEW AND FAR BETWEEN. THE REST OF THE
FORECAST IS ON TRACK.

UPDATE ISSUED AT 1023 PM EDT SAT JUL 26 2014

UPDATED THE FORECAST TO BETTER REFLECT THE TIMING OF THE MCS MOVING
TOWARD THE AREA. THE LAST FEW SCANS...ON THE RADAR...THE MCS
APPROACHING FROM THE WEST IS TENDING TO DIVE TO THE SOUTH. THE
STRONGEST PORTION OF THE SYSTEM MAY JUST EFFECT THE AREA OF EASTERN
KENTUCKY WEST OF I-75. THE HIGHER THETA E VALUES ARE TO THE WEST OF
THE AREA...SO THIS BEHAVIOR AND MOVEMENT OF THE SYSTEM MAKES SENSE.
THE HRRR IS INDICATING THAT THE ST ROMS WILL WEAKEN AS THEY GET TO
EASTERN KENTUCKY. THE BIG SHOW IS STILL TOMORROW AFTERNOON. THE
COMBINATION OF ALL OF THE SEVERE PARAMETERS IS SOMETHING RARELY SEEN
IN EASTERN KENTUCKY IN JULY. WE WILL HAVE ENHANCED STAFFING AT THE
WEATHER OFFICE TOMORROW IN ANTICIPATION OF THE POTENTIAL SEVERE
THUNDERSTORMS TOMORROW AFTERNOON.

&&

.SHORT TERM...(THIS EVENING THROUGH SUNDAY NIGHT)
ISSUED AT 242 PM EDT SAT JUL 26 2014

DYNAMIC SITUATION UNFOLDING OVER THE NEXT 24 TO 36 HOURS AS A DEEP
TROUGH ALOFT DIVES INTO THE OHIO VALLEY. A STRONG COLD FRONT WILL
DROP SOUTHEAST INTO THE REGION SUPPLANTING WHAT WILL BECOME A VERY
WARM AND VERY MOIST AIRMASS IN PLACE ACROSS OUR REGION. THIS
COMBINATION OF A SPRING-TIME SETUP ALOFT COMBINED WITH SUMMER-TIME
HEAT AND HUMIDITY WILL CREATE CONDITIONS FAVORABLE FOR A SIGNIFICANT
SEVERE WEATHER OUTBREAK ON SUNDAY.

MODELS CONTINUE TO INDICATE A THUNDERSTORM COMPLEX WILL ORGANIZE TO
OUR WEST THIS AFTERNOON AND EVENING. THIS APPEARS TO BE HAPPENING
OVER MISSOURI AT THIS TIME. THESE STORMS SHOULD MARCH EASTWARD INTO
THE OVERNIGHT HOURS LIKELY ENDING UP SOMEWHERE OVER SOUTHERN INDIANA
AND NORTHERN KENTUCKY BY OR SHORTLY AFTER MIDNIGHT. THIS COMPLEX
SHOULD BE WEAKENING AS IT ENTERS OUR FORECAST AREA AFTER
MIDNIGHT...BUT CANNOT RULE OUT THE THREAT FOR DAMAGING WINDS AS IT
CROSSES THE REGION. THIS THREAT WOULD BE GREATEST FROM JKL AND
POINTS TO THE NORTH.

THE GREATER SEVERE WEATHER THREAT CONTINUES TO BE THE ANTICIPATED
SECOND ROUND OF THUNDERSTORMS EXPECTED TO ERUPT OVER US OR JUST TO
OUR NORTH SUNDAY AFTERNOON. PROVIDED EARLY MORNING CONVECTION GETS
OUT OF THE WAY IN TIME AND ATMOSPHERE DESTABILIZES AS PROJECTED...
THESE STORMS COULD BE QUITE STRONG. SOUNDINGS TOMORROW AFTERNOON ARE
IMPRESSIVE. STORM RELATIVE HELICITY VALUES EXCEED 300 M2/S2 COMBINED
WITH CAPE PROGGED TO EXCEED 3000 J/KG AND LCLS AROUND 3000 FT MSL.
IF THESE CONDITIONS VERIFY...A RARE JULY TORNADO OUTBREAK COULD
OCCUR. STILL...LOTS OF UNCERTAINTY WITH HOW TONIGHTS ACTIVITY WILL
PAN OUT AND HOW THIS WILL AFFECT OUR CONDITIONS ON SUNDAY BUT WILL
CONTINUE TO PLAY UP THE SEVERE WEATHER POTENTIAL IN OUR SUITE OF
PRODUCTS.

IN ADDITION TO THE SEVERE WEATHER CONCERNS...ISOLATED FLASH FLOODING
IS A CONCERN PRIMARILY ON SUNDAY. MOISTURE POOLING IN ADVANCE OF THE
FRONT WILL PUSH SURFACE DEWPOINTS INTO THE LOW TO MID 70S AND PWATS
WILL JUMP TO 1.75 INCHES AND ABOVE. STORM MOTIONS LOOK FAST ENOUGH
TO PRECLUDE A WIDESPREAD FLASH FLOODING THREAT...BUT AGAIN THAT WILL
DEPEND LARGELY ON HOW PRIMED WE GET BY TONIGHTS CONVECTION. NO FLASH
FLOOD WATCH WILL BE ISSUED AT THIS TIME...BUT THAT MAY NEED TO BE
REVISITED SHOULD THE INITIAL ROUND OF CONVECTION SATURATE THE GROUND
TONIGHT.

.LONG TERM...(MONDAY THROUGH SATURDAY)
ISSUED AT 242 PM EDT SAT JUL 26 2014

AN ANOMALOUS LARGE AND DEEP UPPER TROUGH WILL PERSIST OVER THE
EASTERN CONUS THROUGH THE PERIOD. THE SURFACE COLD FRONT MARKING THE
LEADING EDGE OF THE UNSEASONABLY COOL AIR MASS UNDER THE TROUGH WILL
BE WELL TO OUR SOUTHEAST ALREADY AS THE PERIOD STARTS...BUT RESIDUAL
LOW LEVEL MOISTURE WILL STILL BE MIXING VERTICALLY INTO THE NEW AIR
MASS AS COOLING ALOFT OCCURS. THIS MAY RESULT IN A FEW SHOWERS OR
THUNDERSTORMS MONDAY AFTERNOON OR EVENING...ESPECIALLY IN OUR NE
COUNTIES WHERE COOLER MID LEVEL TEMPS ARE EXPECTED.

ON TUESDAY...DRIER SURFACE AIR AND A MID LEVEL CAP SHOULD KEEP
CONVECTIVE CURRENTS BELOW ABOUT 10K FEET. SOME LIQUID COULD STILL
TRY TO FALL OUT OF THE CLOUDS...BUT WITH LIMITED CLOUD DEPTH AND
DRIER AIR...WILL ONLY MENTION SPRINKLES IN THE FORECAST.

A COOL AND DRY AIR MASS FIRMLY IN PLACE...COUPLED WITH A CESSATION OF
COOLING ALOFT...WILL ALLOW FOR MAINLY CLEAR SKIES FROM TUESDAY NIGHT
THROUGH THURSDAY NIGHT. NEAR RECORD LOW TEMPS WILL BE A POSSIBILITY.

AS THE HIGHLY AMPLIFIED UPPER TROUGH WEAKENS AT THE END OF THE
WEEK...MODELS AGREE ON ITS AXIS RETROGRADING TO THE WEST AS A LOW
CLOSES OFF. WITH THE LOW/TROUGH AXIS SLIPPING TO OUR WEST...WE WILL
RETURN TO ITS EAST SIDE WHICH IS SYNOPTICALLY MORE FAVORABLE FOR
PRECIP. FLOW FROM THE GULF OF MEXICO WILL STILL BE CUT OFF AND LOW
LEVEL MOISTURE WILL BE SLOW TO INCREASE...SO WILL ONLY USE LOW POPS.

&&

.AVIATION...(FOR THE 00Z TAFS THROUGH 00Z SUNDAY EVENING)
ISSUED AT 1023 PM EDT SAT JUL 26 2014

VFR CONDITIONS ARE ANTICIPATED THROUGH THE FIRST HALF OF THE TAF
PERIOD WITH LIGHT WINDS.

UPDATED THE FORECAST TO BETTER REFLECT THE TIMING OF THE MCS MOVING
TOWARD THE AREA. THE LAST FEW SCANS...ON THE RADAR...THE MCS
APPROACHING FROM THE WEST IS TENDING TO DIVE TO THE SOUTH. THE
STRONGEST PORTION OF THE SYSTEM MAY JUST EFFECT THE AREA OF EASTERN
KENTUCKY WEST OF I-75. THE HIGHER THETA E VALUES ARE TO THE WEST OF
THE AREA...SO THIS BEHAVIOR AND MOVEMENT OF THE SYSTEM MAKES SENSE.
THE HRRR IS INDICATING THAT THE ST ROMS WILL WEAKEN AS THEY GET TO
EASTERN KENTUCKY. THE BIG SHOW IS STILL TOMORROW AFTERNOON. THE
COMBINATION OF ALL OF THE SEVERE PARAMETERS IS SOMETHING RARELY SEEN
IN EASTERN KENTUCKY IN JULY. WE WILL HAVE ENHANCED STAFFING AT THE
WEATHER OFFICE TOMORROW IN ANTICIPATION OF THE POTENTIAL SEVERE
THUNDERSTORMS TOMORROW AFTERNOON. EXPECTING MOSTLY MVFR CIGS AND
VSBY FOR THE AREA...HOWEVER SOME OF STRONGER STORMS COULD BE CAPABLE
OF DROPPING THE VSBY TO AROUND A MILE AND PRODUCE WIND GUSTS OF 40
TO 50 KTS. THIS IS MORE LIKELY TO OCCUR WITH STORMS DURING THE
AFTERNOON. PUT TWO TEMPO GROUPS IN THE TAFS TO REFLECT THE MOST
LIKELY TIMES THAT THE STORMS WILL BE IN THE AREA...HOWEVER
THUNDERSTORMS ARE POSSIBLE ANYTIME AFTER ABOUT 5Z.


&&

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

$$

UPDATE...JJ
SHORT TERM...ABE
LONG TERM...HAL
AVIATION...JJ





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