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000
FXUS63 KPAH 260548
AFDPAH

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE PADUCAH KY
1148 PM CST WED FEB 25 2015

.UPDATE...
ISSUED AT 1148 PM CST WED FEB 25 2015

AVIATION UPDATE.

&&

.SHORT TERM...(THIS EVENING THROUGH FRIDAY NIGHT)
ISSUED AT 222 PM CST WED FEB 25 2015

MODELS ARENT QUITE GRASPING THE EXTENT OF MOISTURE/CLOUD COVER
FROM THE SYSTEM TO OUR SOUTH...THOUGH IT IS MAINLY MID AND HIGH
VARIETY THIS FAR NORTH. STILL...WE`VE ADJUSTED SKY COVER GRIDS
UPWARDS THRU THE FIRST 12-24 HOURS OR SO...TO ACCOUNT FOR
MOCLOUDY SKY DURING THIS TIME FRAME. THE SYSTEM LIFTS
NORTH...ENOUGH SO...TO YIELD A CHANCE SNOW MENTION IN OUR FAR
SOUTHEASTERN COUNTIES TONIGHT. SHOULDN`T AMOUNT TO MORE THAN A
HUNDREDTH OR TWO LIQUID EQUIV QPF. AT THE SAME TIME...THE
DEVELOPING NWLY TROF DIPS DOWN...AND INTRODUCES A CHANCE SNOW IN
OUR FAR NORTHWESTERN COUNTIES BY LATE TONIGHT-EARLY TMRW. THE
MOISTURE FIELD REALLY SQUEEZES OUT UPSTREAM OVER MO...BUT MAY
STILL PRODUCES A COUPLE HUNDREDTHS OR SO (CONSISTENTLY SAY THE
MODELS) LIQUID EQUIV QPF FOR THE HEART OF THE NCNTL FA TMRW. IT`LL
CONTINUE TO DISPERSE/DIMINISH AS IT PASSES EAST THRU THE COURSE OF
THE DAY. HOWEVER...WITH MORE ENERGY PINWHEELING AROUND THE BASE OF
THE MEAN LONG WAVE TROF THRU TMRW NIGHT (EARLY)...WE`LL KEEP SOME
CHANCE MENTION OF LIGHT SNOW TAPERING TO FLURRIES OVERNIGHT BEFORE
ENDING. ALL SAID AND TOLD...TRACE (SOUTH) TO HALF INCH (NORTH)
SHOULD COVER THE LOW AND HIGH END RANGES OF THE ANTICIPATED SNOW.

THE PRIMARY EFFECT OF THIS SYSTEM`S PASSAGE WILL BE FELT TMRW
NIGHT-EARLY FRIDAY MORNING...AS THE 1040+ MB SURFACE HIGH WEDGES
ACROSS THE OHIO VALLEY AND BRINGS ITS ARCTIC COLD INTO THE FA WITH
BRUTE FORCE. SO AFTER MUTED THURSDAY HIGHS IN THE 20S NORTH (30S
SOUTH)...WE`LL HAVE RECORD OR NEAR RECORD COLD TMRW NIGHT WITH
FORECAST LOWS IN THE SINGLE DIGITS TO TEENS. THE RECORD LOW
THURSDAY NIGHT IN PADUCAH IS 14 (1963) AND WE ANTICIPATE BREAKING
THAT WITH A FORECAST LOW OF 10. EVV RECORD OF 4 (1934) MAY EVEN BE
APPROACHED WITH OUR FORECAST LOW OF 7. WIND CHILLS AT THE SAME
TIME WILL BE DIPPING INTO THE NEGATIVE SINGLE DIGITS LATE THURSDAY
NIGHT-EARLY FRIDAY MORNING.

.LONG TERM...(SATURDAY THROUGH WEDNESDAY)
ISSUED AT 222 PM CST WED FEB 25 2015

AT THE BEGINNING OF THE EXTENDED FORECAST PERIOD, THE TRANSITION
FROM A FULL TROUGH TO FLAT RIDGING ALOFT ACROSS THE QUAD STATE
REGION IS TAKING PLACE, WITH A SHARP TROUGH IN THE INTERMOUNTAIN
REGION OF THE WESTERN U.S. ATH THE SURFACE, SOUTHERLY FLOW IS
DEVELOPING BEHIND A SURFACE RIDGE HEADING TOWARD THE EAST COAST.

BROAD, BUT RELATIVELY WEAK WARM ADVECTION FLOW/LIFT TAKES PLACE FROM
THE WEST LATE SATURDAY INTO SATURDAY NIGHT. ALLOWING FOR THE
DEVELOPMENT OF LIGHT SNOW SHOWERS DURING THE EVENING.

THE WFO PAH FORECAST AREA STAYS ALONG THE SOUTHERN HALF OF THE BROAD
FLAT RIDGE/CONFLUENT FLOW ALOFT, WITH DIRECT SOUTHERLY FLOW FROM THE
SOUTH/SOUTHEAST U.S.  THIS SHOULD ALLOW FOR THE TRANSITION TO LIQUID
DURING THE DAY ON SUNDAY, THEN DROPPING BACK TO A RAIN/SNOW MIX
SUNDAY NIGHT INTO MONDAY. THIS TAKES PLACE AS HIGH PRESSURE MOVES
DOWN FROM THE UPPER MIDWEST, WITH AGEOSTROPHIC RESPONSE OF NORTHEAST
WINDS MAINTAINING A COLDER GRADIENT OF TEMPERATURES ACROSS THE
REGION.

THE GREATEST UNCERTAINTY IN PRECIPITATION TYPE AND TEMPERATURES WILL
BE LATER MONDAY NIGHT THROUGH TUESDAY EVENING. SURFACE TEMPERATURES
WOULD SUPPORT OVER-RUNNING RAINFALL WITH THE SURFACE FRONTAL
BOUNDARY JUST SOUTH OF THE REGION. CANNOT RULE OUT A PRECIPITATION
MIXTURE, BUT ANY CONCERN SHOULD BE SHORT-LIVED.

THE GFS, WHICH WAS THE PREFERRED GUIDANCE FOR THIS EXTENDED FORECAST
PACKAGE, APPEARS TO SLOWLY DRIFT THE WESTERN U.S. TROUGH INTO THE
CENTRAL PLAINS, WITH A COLDER AIRMASS THAN EXPECTED LATER THIS WEEK.
HOWEVER, WITH THE GULF OF MEXICO FLOW CUT-OFF, PRECIPITATION CHANCES
WILL BE MUCH LESS, BUT MUCH COLDER AIR INTRUSION.

&&

.AVIATION...
ISSUED AT 1148 PM CST WED FEB 25 2015

LARGE AREA OF CLEARING WORKED ACROSS THE AREA...NOT EXACTLY
EXPECTED. WINDS ARE LIGHT...AND SOME SHALLOW LIGHT FOG CANNOT BE
RULED OUT PRIMARILY AT KCGI AND POSSIBLY KPAH. CIGS SHOULD LOWER
ONCE AGAIN LATER TONIGHT INTO THE EARLY MORNING...SETTLING AT MVFR
ACROSS THE AREA FOR THE DURATION THURSDAY...WITH NORTH WINDS
INCREASING TO 10+KTS SUSTAINED. CANNOT RULE OUT A FEW FLURRIES OR
VERY LIGHT SNOW SHOWERS. THIS CAN BE ADDED WHEN CONFIDENCE INCREASES
ON A TIME FRAME...IF NECESSARY.

&&

.PAH WATCHES/WARNINGS/ADVISORIES...
IL...NONE.
MO...NONE.
IN...NONE.
KY...NONE.
&&

$$