FXUS63 KPAH 302339
AFDPAH

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE PADUCAH KY
539 PM CST MON NOV 30 2009

.UPDATE...
UPDATED AVIATION FORECAST DISCUSSION FOR 00Z TAF ISSUANCE. 

&&

.DISCUSSION...
PRIMARY FORECAST CHALLENGE IS POTENTIAL FOR SNOW ON BACK EDGE OF
SYSTEM AS IT DEPARTS. FIRST CHALLENGE IS TRACK OF SYSTEM...W/THE
ECMWF BEING THE PREFERRED MODEL FOR 4 DAYS RUNNING NOW. ITS
SOLUTION...HOWEVER...HAS VARIED RUN-RUN AND NOW IS TRACKING THE
UPPER AND SURFACE LOWS ACROSS WKY...SIMILAR TO THE NAM. NAM
HANDLED YESTERDAYS PCPN BEST AND MAY WELL BE ONTO THIS SYSTEM.
KEEPING W/THE CONSENSUS MODELLING OF ECMWF/SREF AND FACTORING IN
THE NAM TOO...THIS MEANS INCOMING LIQUID PCPN CHANCES LATE TUE
NIGHT...OVERSPREADING THE ENTIRE AREA ON WED. THE THERMAL PROFILE
AS SEEN ON AREA SOUNDINGS AND 1000-850 MB THICKNESS WON'T SUPPORT
CHANGE-OVER TO SNOW TIL 21-24Z WED IN OZARKS OF SEMO...SO BEGAN
MENTION OF SNOW CHANGE-OVER FOR FAR WRN PTNS LATE IN DAY WED.
STILL WILL BE TOUGH TO ACHIEVE W/MAX MIDDAY TEMPS IN THE
L-M40S...MAY BE WAITING CLOSER TO 00Z THU EVEN THERE. BY
THEN/AFTER...THE PCPN IS SHUTTING OFF AS THE LIFT OF THE LOW TAKES
THE PRIMARY MRH FIELD TO THE NORTH AND EAST. NAM AND SOUNDINGS
REVEAL 1-3 HR WINDOW AT BEST FOR CHANGE-OVER WITH CLOSER TO 1 HOUR
WHERE -10 TO -20 C CRYSTALS FALL...IF THEY FALL AS DEPRESSIONS
START DROPPING OFF RAPIDLY WITH ARRIVAL OF DRIER AIR. AS A RESULT
WE DO TRANSLATE THE SNOW CHANCE EASTWARD OVER THE ENTIRE AREA WED
NIGHT BUT ACTUAL SNOW ACCUMS SHOULD RANGE FROM ZERO/TRACE AMOUNTS
(MOSTLY) TO PERHAPS A HALF INCHISH/MAINLY ON GRASSY SURFACES...WHAT
W/ GROUND TEMPS STILL RUNNING IN THE UPPER 40S. OVERNIGHT LOWS
WON'T HIT FREEZING TIL CLOSER TO 12Z THU...BY THEN ALL PCPN IS OUT
OF THE AREA SAVE FOR A FLURRY CHANCE IN THE FARTHEST NERN
PTNS/PROBABLY NOT EVEN WORTHY OF MENTION.

BEFORE AND AFTER THIS SYSTEM WE HAVE A DRY WEATHER FORECAST.
WARMING TOMORROW WILL BE FOLLOWED BY COOLING LATE IN THE
WEEK...MODERATING SOME INTO NEXT WEEKEND. THE GFS HAS BEEN TRYING
TO SUGGEST SOME DAYS 6-7 POPS W/THE UPPER FLOW BACKING TO MOISTURE
TRANSPORTING SWLYS...HOWEVER IT'S BEEN THE COLLAB CONSENSUS TO
STICK W/THE ECMWF WHICH KEEPS DRIER WLY-NWLY TRAJECTORIES THRU 
DAY 7 AND HENCE A DRY WX ENDING FORECAST FOR NOW.

&&

.AVIATION...
SKIES HAVE FINALLY CLEARED ACROSS THE ENTIRE AREA. LIGHT AND
VARIABLE WINDS WILL BE THE RULE TONIGHT...AS SFC HIGH PRESSURE
BUILDS INTO THE AREA. THIS AREA OF HIGH PRESSURE WILL MOVE OFF TO
THE EAST ON TUESDAY...WHICH WILL RESULT IN WINDS BECOMING
SOUTHERLY. SKIES SHOULD REMAIN MAINLY CLEAR FOR THE NEXT 24
HRS...OTHER THAN SOME INCREASING HIGH CLOUDS ON TUESDAY.

&&

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

$$