Area Forecast Discussion
Issued by NWS Paducah, KY

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000
FXUS63 KPAH 271908
AFDPAH

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE PADUCAH KY
108 PM CST FRI FEB 27 2015

.SHORT TERM...(THIS EVENING THROUGH SUNDAY)
ISSUED AT 1252 PM CST FRI FEB 27 2015

ANOTHER RECORD OR NEAR RECORD NIGHT OF COLD IS ON TAP FOR TONIGHT
AS THE 1040+ MB SURFACE HIGH MOVES ACROSS THE MISSISSIPPI RIVER
VALLEY AND ANCHORS OVER THE OHIO RIVER VALLEY BY 12Z FRIDAY. THE
RECORD LOW AT PAH IS 17 (1993) AND WE FORECAST 15. THE RECORD LOW
FOR EVV IS 4 (1993) AND WE FORECAST 12. WIND CHILLS WILL ALSO DROP
INTO/THRU THE SINGLE DIGITS AND BOTTOM OUT NEAR ZERO IN SOME
LOCATIONS...MAINLY NORTHERN REACHES OF THE QUAD STATE.

SATURDAY...WITH THE HIGH TO THE EAST...A LIGHT RETURN ELY FLOW
AROUND THE HIGH MEANS THE MODERATION IN TEMPS WILL BE GRADUAL. WE
SHOULD SEE ABOUT A 20 DEGREE DIURNAL REBOUND...WHICH PUTS ALL
SITES INTO THE 30S...WITH THE NORTHERN HALF FLIRTING WITH 32F AND
THE SOUTHERN HALF OR SOUTHEASTERN PARTS NUDGING TOWARD 40F. IN THE
SEMO OZARKS...TEMPS MAY HALT THEIR RISE IN THE LOW-MID 30S...AS
MOISTURE FIELD CURRENTLY SEEN ACROSS THE SOUTHERN PLAINS
EXPANDS/MOVES INTO THE OZARKS DURING THE PM AND PRODUCES SMALL
LIGHT SNOW CHANCES FOR OUR WESTERN FOUR OR FIVE OZARK SEMO
COUNTIES.

SATURDAY NIGHT...THE PCPN FIELD EXPANDS NORTHWARD AND EASTWARD ACROSS
THE QUAD STATE. SOUNDING DATA SUGGESTS THE UPPER LEVELS WILL BE
COLD AND THIS WILL BE MAINLY A SNOW CHANCE AT 00Z SUNDAY. BUT BY
06Z SUNDAY...THE WARM NOSE REALLY GETS GOING...AND PCPN
CHANCES...DEPENDING UPON SURFACE TEMPS...WILL TRANSITION TO A
WINTRY MIX. THIS WILL BE MOST MARKED ACROSS OUR FAR NORTHERN AND
WESTERN COUNTIES...ALIGNED CLOSELY WITH THE WPC DAYS 2-3 WX
DEPICTION. THIS PERIOD OF ICY/SNOWY MIX WILL LAST INTO EARLY SUNDAY
MORNING...AFTER WHICH THE TEMP RISE EVERYWHERE WILL BE SUFFICIENT
TO CHANGE ALL PCPN OVER TO ALL RAIN FOR MUCH OF SUNDAY. AFTER A
SAT NIGHT LOW IN THE UPPER 20S TO LOWER 30S...SUNDAY HIGHS WILL
RANGE FROM UPPER 30S TO ALMOST 50.

.LONG TERM...(MONDAY THROUGH THURSDAY)
ISSUED AT 400 AM CST FRI FEB 27 2015

EXCEPTIONALLY BUSY WEEK COMING UP...WITH TIMING DIFFERENCES BETWEEN
MODELS AND MODEL RUNS MAKING THINGS CHALLENGING TO SAY THE LEAST.

PRECIPITATION WILL BE ONGOING SUNDAY NIGHT...AS AN INCOMING FRONTAL
BOUNDARY PASSES THROUGH THE AREA. THE ECMWF CONTINUES TO BE FASTER
IN BRINGING IT THROUGH WHILE THE NEWEST RUN AND PREVIOUS RUNS OF THE
GFS ARE A BIT SLOWER. HIGHEST POPS WILL BE DURING THE EVENING WITH
DECREASING POPS AFTER MIDNIGHT FROM NORTHWEST TO SOUTHEAST. SHALLOW
COLD AIR POURS BACK INTO THE REGION BEHIND THIS FRONT. THIS WILL
MEAN A CHANCE FOR THE RAIN TO CHANGE OVER TO FREEZING RAIN/SLEET AS
THE WARM LAYER ALOFT REMAINS IN PLACE.

MONDAY IS LOOKING DRIER AND DRIER WITH EACH MODEL RUN AS HIGH
PRESSURE BUILDS IN. HAVE BACKED OFF POPS EVEN MORE WITH THIS
PACKAGE. IF ANYTHING IS LEFT ON MONDAY MORNING...IT WILL BE IN THE
FAR SOUTH AND IT COULD STILL BE SOME FREEZING RAIN. LEFT MONDAY
AFTERNOON DRY.

MODEL CONTINUITY AND AGREEMENT FADES BY THE TIME YOU GET TO MONDAY
NIGHT. MODELS HAD BEEN IN DECENT AGREEMENT WITH A WARM FRONT LIFTING
BACK NORTH ACROSS US...WITH MOISTURE/QPF RETURNING IN EARNEST AS
EARLY AS MONDAY EVENING. THE ECMWF HAS REALLY BACKED OFF ALMOST
LEAVING US FAIRLY DRY THE ENTIRE NIGHT. THE GFS HAS BACKED OFF A
BIT...ADVERTISING A MAINLY AFTER MIDNIGHT EVENT. THE CANADIAN MODEL
IS THE MOST AGGRESSIVE BUT BELIEVE THE STRENGTH OF THE SFC HIGH WILL
LIKELY PROLONG THE RETURN FLOW. WILL SPLIT THE MONDAY NIGHT WX GRID
TO SHOW LOWER POPS DURING THE EVENING AND THEN RAMPING THINGS UP
AFTER MIDNIGHT. THIS RAMP UP IN PRECIP IS HIGHLY SUPPORTED BY THE
GFS PRECIP MEAN AND MANY OF THE ENSEMBLE MEMBERS. THE CONCERN OVER
TEMPERATURES AND HENCE PRECIPITATION TYPE WITH THIS RETURN MOISTURE
DOES NOT LOOK LIKE AS BIG A CONCERN NOW...AS EVERYTHING SUGGESTS WE
WILL BE WARM ENOUGH FOR A LIQUID EVENT.

THE MAIN LOW PRESSURE SYSTEM TO IMPACT THE AREA FOR TUESDAY THROUGH
WEDNESDAY WILL EJECT OUT OF THE ROCKIES AND MOVE EAST NORTHEAST
TOWARD THE GREAT LAKES. THERE CONTINUES TO BE TIMING ISSUES BETWEEN
MODELS. HOWEVER...THE PERIOD OF TUESDAY THROUGH WEDNESDAY DOES LOOK
TO BE AN ACTIVE PERIOD WITH SHOWERS AND THUNDERSTORMS COMMONPLACE.
THE FRONT ASSOCIATED WITH THE SYSTEM WILL MOVE THROUGH EITHER
TUESDAY NIGHT OR WEDNESDAY MORNING. THERE WILL CONTINUE TO BE TWEEKS
EVERY DAY TO FINE TUNE THE TIMING OF THIS SYSTEM BUT THERE IS HIGH
CONFIDENCE OF A PERIOD OF RAINFALL...SOME OF IT HEAVY AT TIMES WHICH
WILL CAUSE FLOODING CONCERNS...IN THE TUESDAY THROUGH WEDNESDAY TIME
FRAME. IN FACT PRECIPITABLE WATER VALUES ON TUESDAY ARE ABOVE THE
99TH PERCENTILE FOR THIS TIME OF YEAR.

WEDNESDAY CONTINUES TO BE CHALLENGING DUE TO THE TIMING
DIFFERENCES. THE 00Z ECMWF SHOWS THE ACTUAL FRONT MOVING THROUGH
WITH HEAVY RAIN MOVING ACROSS THE AREA. THE 00Z GFS INDICATES THAT
THE FRONT WOULD ALREADY BE THROUGH BUT A SECONDARY IMPULSE WOULD
TRAVERSE THE AREA IN ITS WAKE AND IT WOULD BE COLD ENOUGH FOR SNOW.
LOTS OF TIME TO FIGURE OUT WHAT EXACTLY WILL OCCUR.

TEMPERATURES WILL ALSO BE PROBLEMATIC. TEMPS IN THE 50S/60S LOOK
LIKELY SOMETIME TUESDAY INTO WEDNESDAY MORNING BEFORE THEY CRASH
BEHIND THE FRONT. THESE TEMPERATURES...ALONG WITH DEWPOINTS CLIMBING
INTO THE 50S AND STRONG WINDS THROUGHOUT THE ATMOSPHERE COULD ALSO
LEAD TO POSSIBLE SEVERE WEATHER SOMETIME IN THE TUESDAY THROUGH
WEDNESDAY PERIOD. STAY TUNED.

&&

.AVIATION...
ISSUED AT 1252 PM CST FRI FEB 27 2015

IR SATELLITE SHOWS DIURNAL CU DEVELOPING...RANGING FROM MVFR TO
LOW VFR. IT WILL BE MOST PRONOUNCED AT KEVV/KOWB...LESS SO AT KPAH
AND KCGI. MID CIGS WILL BE ADVANCING FROM THE WEST...OVERTAKING
KCGI SOON...PERHAPS PRECLUDING A DIURNAL CU CIG. AFTER
23Z-24Z...DIURNAL FUEL IS LOST AND MID CIGS SATURATE DOWN INTO THE
5-7K FT RANGE OVERNIGHT FOR ALL TERMINALS...AND SHOULD CONTINUE
THERE INTO THE PLANNING PERIOD.

&&

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

&&

$$


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