FXUS63 KGID 110342
AFDGID

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE HASTINGS NE
942 PM CST THU DEC 10 2009

.DISCUSSION...UPDATED THE FORECAST FOR TONIGHT TO RAISE
TEMPERATURES AND DEWPOINTS. SOUTHWEST WIND WILL HELP KEEP
TEMPERATURES FROM DROPPING AS MUCH AS PREVIOUSLY FORECAST.
DEWPOINTS ARE ALSO RUNNING WARMER THAN THE PREVIOUS FORECAST AS 
WELL. 

&&

.PREV DISCUSSION... /ISSUED 442 PM CST THU DEC 10 2009/ 

AVIATION...00Z KGRI TAF. THE TERMINAL WILL BE POSITIONED ON THE 
BACK SIDE OF SURFACE HIGH PRESSURE AND EAST OF A SURFACE TROUGH ON
THE LEE SIDE OF THE ROCKY MOUNTAINS. THIS WILL MAINTAIN A 
GENERALLY SOUTH/SOUTHWEST COMPONENT TO THE WIND...AND WIND WILL 
REMAIN RELATIVELY LIGHT. SKY WILL REMAIN CLEAR...WITH A POSSIBLY 
SOME CIRRUS FROM TIME TO TIME TONIGHT/FRIDAY. 

PREV DISCUSSION... /ISSUED 302 PM CST THU DEC 10 2009/ 

SHORT TERM...TONIGHT THROUGH 12Z SATURDAY.  THE PRIMARY ISSUE IN 
THE NEAR TERM WILL BE TEMPERATURES.  A COLD AND QUIET PERIOD IS 
EXPECTED TONIGHT AND FRIDAY.  SKIES WILL REMAIN RELATIVELY CLEAR 
THIS EVENING...HOWEVER THERE COULD BE SOME INCREASE IN MID AND HIGH 
LEVEL CLOUDS TOWARDS MIDNIGHT AS A WAVE CROSSES THE REGION.  THIS 
COMBINED WITH THE SNOW ON THE GROUND SHOULD AGAIN LEAD TO A NIGHT OF 
COLD TEMPERATURES...AND HAVE CUT NAM/GFS MOS GUIDANCE VALUES BY 
SEVERAL DEGREES AND TENDED TO FAVOR THE 12Z NAM BIAS CORRECTED 
OUTPUT FOR LOWS TONIGHT.  AM A BIT CONCERNED THAT THIS MAY NOT EVEN 
BE LOW ENOUGH IN SOME SPOTS...ESPECIALLY FOR THE AREAS THAT FELL 
INTO THE TEENS BELOW ZERO LAST NIGHT/THIS MORNING.

TEMPERATURES REMAIN A BIT TRICKY ON FRIDAY WITH THE SNOW ON THE 
GROUND...HOWEVER H85 WARM AIR ADVECTION WILL HELP INCREASE H85 
TEMPERATURES INTO THE AFTERNOON.  OBVIOUSLY THERE IS NO CHANCE THAT 
WE MIX TO THE LEVEL...BUT THERE IS AT LEAST SOME MODIFICATION TO THE 
LOW LEVEL AIR MASS...AND THAT COULD HELP TEMPERATURES RISE INTO THE 
LOWER TO MID 20S.  WARM AIR ADVECTION CONTINUES TO RIDE OVER THE TOP 
OF THE COLD LOW LEVEL AIR MASS FRIDAY NIGHT...WITH INCREASING 
MOISTURE/SATURATION SHOWN BELOW H9.  THIS MAY LEAD TO SOME LATE 
NIGHT FOG OR FREEZING DRIZZLE...BUT CURRENT INDICATIONS ARE THE 
BETTER CHANCES FOR THAT WOULD PROBABLY BE TOWARDS SATURDAY 
MORNING...SO LEFT IT OUT OF FRIDAY NIGHT FOR NOW.

LONG TERM...12Z SATURDAY THROUGH THURSDAY. MAIN FORECAST CONCERNS 
WILL BE CHANCE FOR SOME FREEZING DRIZZLE SATURDAY AND TEMPERATURES 
THROUGH THE PERIOD. 

A WEAK SHORT WAVE WILL MOVE THROUGH THE FORECAST AREA ON SATURDAY. 
THERE IS SOME WARM ADVECTION WITH A LITTLE MOISTURE THAT MOVES 
ACROSS COLDER AIR AT THE SURFACE. THERE IS A SHALLOW LAYER OF 
MOISTURE NEAR THE SURFACE ESPECIALLY IN THE SOUTHEAST PART OF THE 
FORECAST AREA. WITH MINIMAL MOISTURE IN THE DENDRITIC LAYER THERE 
WILL BE NO ICE INTRODUCED INTO THE COLD MOIST LAYER NEAR THE 
SURFACE. EXPECT THAT THERE COULD BE A LITTLE FREEZING DRIZZLE FOR 
THE SOUTHEAST PART OF THE AREA. DO NOT EXPECT THAT THERE WILL BE 
VERY MUCH ACCUMULATION BUT IT DOES NOT TAKE MUCH TO MAKE THINGS 
SLIPPERY. BY SATURDAY EVENING THE LOW LEVEL MOISTURE DIMINISHES 
SOMEWHAT AND EXPECT THE DRIZZLE TO COME TO AN END. 

TEMPERATURES CONTINUE TO BE SOMEWHAT OF A CHALLENGE. TEMPERATURES AT 
850MB FLUCTUATE FREQUENTLY THROUGH THE PERIOD WITH FAIRLY LARGE 
TEMPERATURE SWINGS. IN ADDITION MODELS TEND TO HAVE DIFFERENT TIMING 
WITH EACH TEMPERATURE SWING. AT THIS TIME IT APPEARS THAT THERE WILL 
BE A GRADUAL WARMING TREND FOR SATURDAY INTO SUNDAY. A COLD FRONT 
MOVES THROUGH THE AREA SUNDAY NIGHT AND THE TEMPERATURES SHOULD COOL 
OFF AGAIN. THE COOL HIGH PRESSURE THAT BRINGS IN THIS ROUND OF 
COOLER AIR MAINLY STAYS FURTHER NORTHEAST AND GIVES THE FORECAST 
AREA COOLER AIR BUT NOT AS COLD AS FURTHER NORTHEAST. ON TUESDAY THE 
COLD SURFACE HIGH MOVES OFF TO THE EAST AND TEMPERATURES START TO 
WARM UP IN THE SOUTHWEST TUESDAY BUT THE WARMER AIR WILL MAINLY WAIT 
UNTIL THURSDAY BEFORE IT REALLY IMPROVES.

&&

.GID WATCHES/WARNINGS/ADVISORIES...
NE...NONE.
KS...NONE.
&&

$$

HEINLEIN