621 
FXUS63 KLBF 232118
AFDLBF

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE NORTH PLATTE NE
317 PM CST MON DEC 23 2002

.FORECAST CHALLENGE TO BE TEMPS...

12Z H5 UPPER AIR ANALYSIS HAS WRN HALF OF THE CONUS IN SPLIT FLOW. 
NRN STREAM HAS CARVED OUT A TROF OVER THE GREAT LAKES AND NEW 
ENGLAND WITH A CUTOFF LOW CENTERED OVER CENTRAL QUEBEC. FARTHER 
WEST...CUTOFF LOW OVER SRN NEVADA WITH SEVERAL EMBEDDED SHORTWAVES 
EVIDENT...FIRST OVER BAJA CALIFORNIA AND SECOND OVER FAR WRN TX. H25 
ANALYSIS SHOWING COUPLED JET ACROSS TX. AT THE SFC...HIGH PRESSURE 
REMAINS OVHD WITH THE DECENT ERLY FLOW WELL SOUTH OF THE FA. MAIN 
ISSUE TODAY HAS BEEN THE HIGH CLOUDINESS ASSOCIATED WITH THE STORM 
SYSTEM ACROSS THE RED RIVER VALLEY AND THEIR IMPACT ON AFTN HIGHS.  

.TONIGHT AND CHRISTMAS EVE...SFC HIGH PRESSURE BUILDS OVHD TONIGHT 
SUPPRESSING PCPN WELL S OF FA. SOME MID TO HIGH CLOUDINESS WILL 
CONTINUE TO SPILL INTO THE SRN FA...THIS WILL HELP TO GIVE A BOOST 
TO OVERNIGHT LOWS. ELSEWHERE...CLOUD CANOPY WILL BE VERY HIGH AND 
THIN...AND WITH HIGH PRESSURE OVHD...AND VERY DRY AIR IN 
PLACE...TEMPS SHOULD BE AT OR SLIGHTLY BELOW THIS MORNINGS READINGS. 
UPPR TROF BUILDS E TOMORROW ALLOWING FOR MOSTLY CLEAR SKIES ACROSS 
THE BULK OF THE FA. WITH COLD ARCTIC AIR REMAINING IN 
PLACE...TEMPERATURES IN THE LOWER TO MID 30S WILL BE IN ORDER. SFC 
HIGH DRIFTS INTO THE RED RIVER VALLEY TOMORROW NIGHT...THIS WILL SET 
UP LIGHT WRLY SFC WINDS LEADING TO VERY COLD TEMPS OVERNIGHT. 
GUIDANCE TEMPS IN THE HIGH SINGLE DIGITS TO LWR TEENS LOOK GOOD AT 
THIS JUNCTURE. 

.CHRISTMAS AND THURSDAY...UPPR PATTERN TRANSITIONS TO A WNWRLY FLOW 
ON WEDNESDAY. WITH WRLY COMPONENT IN  PLACE...LL WARMING WILL BEGIN. 
H85 TEMPS INDICATING A WARMUP INTO THE 30S AND THIS LOOKS 
REASONABLE. OVERNIGHT...UPPER LEVEL DISTURBANCE TRAVERSES THE NRN 
PLAINS...HOWEVER WITH DRY ATM...WIDESPREAD CLOUDINESS WILL BE NON 
EXISTENT. CONTINUED DRY LL AND LIGHT WRLY WINDS WILL LEAD TO ANOTHER 
VERY COLD NIGHT WITH READINGS IN THE SINGLE DIGITS. DISTURBANCE 
MOVES E OF FA ON THURSDAY...WITH LOW AMPLITUDE RIDGING BUILDING INTO 
THE WRN CONUS ON THURSDAY. TEMPS WILL CONTINUE A SLIGHT UPWARD 
MODIFICATION WITH READINGS 3-7 DEGREES WARMER THAN WEDNESDAYS. 

.FRIDAY THROUGH MONDAY...DECENT WARMUP ON FRIDAY AND SATURDAY AS 
UPPR RIDGE BUILDS INTO THE CENTRAL CONUS. H85 TEMPS INDICATIVE OF 
TEMPS CLOSE TO 50 IN THE W ON FRIDAY...UPPR 40S ON SATURDAY. TROF 
TRAVERSES NRN TIER LATE ON SATURDAY. THIS WILL DROP AN ARCTIC FRONT 
INTO THE FA SATURDAY NIGHT BRINGING TEMPS CLOSER TO NORMAL. MRF 
MODEL QPF ON SUNDAY SEEMS OVER DONE AND ENSEMBLE MEMBERS ARE 
INDICATING LARGEST RUN TO RUN INCONSISTENCIES ACROSS THE CENTER OF 
THE CONUS. WITH BEST JET DYNAMICS S OF FA AND BONE DRY AIR IN PLACE 
FROM THE SFC TO H5...FCST WILL REMAIN DRY SUNDAY AND MONDAY. AS FOR 
TEMPERATURES...SEASONAL TEMPS ON SUNDAY WILL BE FOLLOWED BY SLIGHTLY 
BELOW NORMAL TEMPS ON MONDAY AS BACK DOOR ARCTIC AIR BECOMES 
ENTRENCHED ACROSS FA.  

.LBF...NONE.

CLB