FXUS63 KPAH 092049
AFDPAH

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE PADUCAH KY
245 PM CST WED DEC 9 2009

.DISCUSSION...
MAIN CONCERNS ARE WIND CHILLS TONIGHT...AND THEN POP POTENTIAL 
FRIDAY THROUGH TUESDAY.

DEEP SURFACE LOW PULLING AWAY FROM THE REGION THIS AFTERNOON...AND 
WINDS HAVE DROPPED TO BELOW ADVISORY CRITERIA...SO THE WIND ADVISORY 
WILL BE ALLOWED TO EXPIRE AS SCHEDULED AT 3 PM. WINDS WILL CONTINUE 
TO BE QUITE STRONG AND GUSTY TONIGHT...AS SURFACE HIGH PRESSURE 
BUILDS IN TO OUR SOUTHWEST. COLD...DRY ADVECTION WILL CONTINUE 
THROUGH THE NIGHT AND MUCH OF THURSDAY. GENERALLY FOLLOWED THE 
COLDER MET NUMBERS TONIGHT AND THURSDAY. RESULTANT WIND CHILLS IN 
THE 09Z-15Z TIMEFRAME WILL BOTTOM OUT FROM ZERO TO 10 ABOVE 
THROUGHOUT THE AREA. WILL CONTINUE TO HIGHLIGHT THIS COLDEST AIR OF 
THE SEASON IN THE HWO AND ONLINE. 

THURSDAY NIGHT WILL SEE THE SURFACE HIGH SETTLE OVER THE QUAD STATE 
REGION. SO GOOD RADIATIONAL COOLING WITH A VERY DRY AIRMASS IN PLACE 
WOULD TYPICALLY LEAD TO THE COLDEST NIGHT OF THIS COLD 
OUTBREAK...BUT GUIDANCE IS HARDLY COLDER THAN TONIGHT. WILL LEAN 
TOWARD COOLER MET GUIDANCE...BUT WILL NOT BE SURPRISED IF IT ENDS UP 
BEING COLDER THAN ALL GUIDANCE.

FOR FRIDAY THROUGH TUESDAY...THE FLOW ALOFT BECOMES NEARLY 
ZONAL...BUT REMAINS QUITE FAST. A PAIR OF DISTURBANCES WILL IMPACT 
THE AREA...ONE SATURDAY INTO SUNDAY...AND THE OTHER STRONGER ONE 
MONDAY INTO TUESDAY. THE ECMWF AND GFS SEEM TO BE TRENDING DRIER AND 
FASTER WITH THE SECOND SYSTEM. HOWEVER...WITH THE ARCTIC AIRMASS IN 
PLACE...IT WILL BE DIFFICULT TO GET DECENT MOISTURE RETURN AHEAD OF 
EITHER ONE. THE MODELS ARE SPITTING OUT LOTS OF LIGHT QPF THROUGHOUT 
THE PERIOD FROM SATURDAY NIGHT THROUGH MONDAY NIGHT. 

COULD EASILY SPREAD 20-30 POPS THROUGHOUT THE AREA FROM SATURDAY 
THROUGH TUESDAY...BUT TRIED TO CONFINE POPS TO 2 DISTINCT PERIODS. 
GENERALLY FOLLOWED THE 12Z GFS...WHICH SATURATES THE LOWEST 6-9KFT 
OVER MUCH OF THE AREA IN RETURN FLOW BY SATURDAY AFTERNOON...AND 
THEN KEEPS IT IN PLACE THROUGH THE NIGHT AND INTO SUNDAY MORNING. 
MODEL SOUNDINGS INDICATE THAT THE TEMPERATURES WOULD BE ABOVE 
FREEZING THROUGHOUT THE UNSATURATED LAYER...SO WARM RAIN PROCESSES 
WOULD LEAD TO OVERGROWN DRIZZLE...IF IT HAPPENS AT ALL. KEPT 
PRECIPITATION ALL RAIN FOR NOW...WITH LOWS SATURDAY NIGHT MAINLY IN 
THE MIDDLE 30S.

THE OTHER POP PERIOD IS FROM MONDAY INTO TUESDAY. BOTH THE ECMWF AND 
GFS INDICATE A SHARPER SYSTEM MOVING THROUGH THE REGION MONDAY. THE 
GFS HAS ANOTHER ARCTIC AIRMASS COMING IN BEHIND THE ASSOCIATED COLD 
FRONT...WHILE THE ECMWF DOES NOT. DESPITE THIS DIFFERENCE...THEY 
BOTH BRING THE FRONT THROUGH THE REGION MONDAY. THERE WILL BE LITTLE 
MOISTURE FOR THIS SYSTEM TO WORK WITH...SO WILL KEEP POPS IN THE 
20-30 RANGE. 

TUESDAY WILL PROBABLY BE DRY...BUT WILL KEEP THE POPS JUST TO MAKE 
SURE THE MODELS ARE CONSISTENT. MENTIONED SOME RAIN OR SNOW IN THE 
NORTH FOR LATE MONDAY NIGHT AND TUESDAY...WHEN SOME SUB-FREEZING AIR 
COULD REACH THE AREA. HOWEVER...FEEL THAT MOST OF THE 
PRECIPITATION...IF THERE IS ANY...WILL BE RAIN AND WILL BE OUT OF 
THE WAY BEFORE THE FREEZING AIR ARRIVES.

&&

.AVIATION...
WINDS WILL REMAIN STRONG AND GUSTY THIS AFTERNOON...ESPECIALLY 
THROUGH EARLY AFTERNOON. EXPECT TO LOSE GUSTS AT KPAH AND KCGI AFTER 
SUNSET BUT KEEP THEM IN AT KEVV AND KOWB. ASIDE FROM THE STRONG 
WINDS...THE ONLY ISSUE WILL BE LOW CLOUDS. VIS SAT SHOWS SOUTHERN 
EDGE OF CLOUDS WAS RAPIDLY ERODING. THIS WILL KEEP KPAH AND KCGI 
UNLIMITED VFR THROUGH THE VALID TIME OF THE TAF. KEVV AND KCGI MAY 
CLEAR OUT A FEW HOURS THIS AFTERNOON...FORECAST SOUNDINGS SUGGEST A 
CHANCE OF MVFR BKN CIGS BETWEEN 00Z AND 06Z. AFTER THAT ALL SITES 
VFR.

&&

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

&&

$$

PUBLIC....DRS
AVIATION..KH