FXUS63 KLBF 232130
AFDLBF
AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE NORTH PLATTE NE
331 PM CST WED DEC 23 2009
.SYNOPSIS...WV IMAGERY THIS AFTERNOON...INDICATING A CLOSED
CIRCULATION OVER CENTRAL NM...WITH A LEAD SHORTWAVE...ENTERING
CENTRAL PORTIONS OF NEBRASKA. THE LATTER HAS SPREAD LIGHT SNOW TO A
LARGE PORTION OF CENTRAL AND S CENTRAL NEBRASKA AND FREEZING RAIN TO
SERN AREAS. SURFACE ANALYSIS AT 18Z INDICATING A FRONTAL BOUNDARY
EXTENDING ACROSS THE SRN TX PANHANDLE...ALONG THE RED RIVER TO
WICHITA FALLS TX...THEN NEWD INTO SWRN MO. AN ARCTIC FRONT EXTENDED
ACROSS NRN WYOMING INTO THE NWRN SODAK AND WRN NODAK.
.DISCUSSION...
NEAR TERM...TONIGHT THROUGH SATURDAY NIGHT...STORM SYSTEM STILL
APPEARS TO COME AT US IN TWO PIECES OVER THE NEXT 24 TO 48 HOURS.
ONGOING SNOW AND LEAD UPPER LEVEL DISTURBANCE WILL LIFT NORTH FROM
SRN NEBR TONIGHT INTO THE NERN CWA BY MORNING. DEFORMATION ZONE WILL
PIVOT NORTH AND WEST OF THIS FEATURE TONIGHT...WITH THE GREATEST
SNOW ACCUMS EAST OF A LINE FROM NORTH PLATTE TO VALENTINE.
ISENTROPIC UPGLIDE WILL REMAIN PREVALENT THROUGH MIDNIGHT...THEN
WEAKEN OVERNIGHT OVER THE EASTERN CWA TOWARD THURSDAY MORNING. EVEN
WITH THE LOWER THAN EXPECTED SNOW ACCUMULATIONS TODAY...STILL FEEL A
WINTER STORM WARNING IS PROBABLY IN THE BEST INTEREST OF THE PUBLIC
BASED ON WIND AND BLOWING SNOW POTENTIAL TOMORROW. BASED ON THE LACK
OF SNOWFALL OFF TO OUR WEST...AS WELL AS PORTIONS OF THE WESTERN
SANDHILLS AND SOUTHEASTERN PANHANDLE...WOULDN'T BE SURPRISED IF THE
WINTER STORM WARNING WAS DROPPED IN THESE AREAS. AGAIN...UNTIL
ACCUMULATIONS CAN BE TABULATED IN THESE AREAS...FEEL BEST BET IS TO
STAY THE COURSE ON THE WARNING ATTM DUE TO BLOWING SNOW POTENTIAL
TOMORROW.
FOR THURSDAY AND THURSDAY EVENING...THE WESTERN HALF OF THE FORECAST
AREA SHOULD SEE A BRIEF REPRIEVE FROM SNOW AS A NRN STREAM LOW DIVES
SOUTH INTO THE BLACK HILLS. MODEL TREND WITH THIS FEATURE HAS BEEN
SLOWER THIS MORNING...WHICH WOULD FAVOR THE SRN STREAM LOW TRACKING
FURTHER SOUTH...THEN EAST...EMERGING INTO SOUTHWESTERN MO BY 00Z
FRIDAY. FOR WESTERN LOCATIONS...DRIER AIR...AND ISENTROPIC
DOWNGLIDE...WILL HINDER PRECIPITATION FORMATION ACROSS THE WEST AND
SOUTHWEST FOR THURSDAY. FURTHER EAST...LIGHT PRECIPITATION WILL
CONTINUE IN THE FORECAST...AS WEAK LIFT ON THE NRN AND NNWRN FLANK
OF THE SRN LOW PUSHES WEST INTO EASTERN SECTIONS OF NEBRASKA
THURSDAY AFTERNOON. IN ALL LOCATIONS...WINDS WILL INCREASE THURSDAY
AS HIGH PRESSURE BUILDS INTO THE NRN ROCKIES AND LOW PRESSURE DEEPENS
OVER THE OZARKS. GRADIENT IS SOMEWHAT WEAKER IN THE MODELS TDY FOR
TOMORROW THURSDAY EVENING...SO BLIZZARD CONDS SEEM UNLIKELY DURING
THESE PERIODS...ALBEIT STRONG ENOUGH TO CONTINUE TO WARRANT WSW
HEADLINES.
ON FRIDAY...BOTH THE NRN AND SRN SYSTEMS WILL CONGEAL ACROSS NRN MO
SRN IA WITH SURFACE PRESSURE DEEPENING RAPIDLY OVER NRN MO. PRESSURE
GRADIENT WILL TIGHTEN SIGNIFICANTLY EARLY FRIDAY INTO FRIDAY NIGHT
WITH THE HIGHEST WINDS EXPECTED DURING THESE PERIODS. WRAPAROUND
SNOW IS EXPECTED TO TRACK SOUTH INTO NORTHERN AND CENTRAL NEBRASKA
FRIDAY AND FRIDAY NIGHT AS THE UPPER LEVEL LOW WOBBLES ACROSS IA AND
MN. PROLONGED...WEAK ISENTROPIC UPGLIDE AND AMPLE MOISTURE IN THE
DENDRITIC LAYER...WILL MAKE FOR EFFICIENT SNOW PRODUCTION FRIDAY.
HAVE RAMPED UP POPS IN THE NORTH AND CENTRAL AREAS FOR FRIDAY...AND
AM EXPECTING CONDS TO BE MORE HAZARDOUS IN THESE AREAS ON FRIDAY VS.
PREVIOUSLY THOUGHT ON THURSDAY. HAVE ADVISED INCOMING SHIFT ON THE
POSSIBILITY OF EXTENDING THE WSW FURTHER INTO FRIDAY NIGHT.
LONG TERM...SATURDAY THROUGH WEDNESDAY...
WEAK RIDGING DEVELOPS BY SUNDAY IN THE WAKE OF THE MAJOR STORM
SYSTEM...MEANWHILE ANOTHER TROF DIGS OVER WESTERN CAL COAST. THE
RIDGE WILL SLOWLY MIGRATE ACROSS THE CENTRAL PLAINS OVER THE
BEGINNING OF THE WEEK AS THE TROF DIGS...APPROACHING THE US/MEX
BORDER EARLY IN THE WEEK. THE RIDGING WILL PROVIDE DRY
CONDITIONS...HOWEVER SNOW PACK OVER THE PLAINS WILL HELP HOLD
TEMPERATURES BELOW NORMAL. HIGHS DESPITE PARTLY SUNNY SKIES WILL
STRUGGLE TO REACH INTO THE 20S...WHILE LOWS WILL DIP INTO THE SINGLE
DIGITS...LOCALLY BELOW ZERO WILL BE POSSIBLE.
&&
.AVIATION...
GENERALLY IFR OR LOWER CONDITIONS WILL CONTINUE THROUGH FRIDAY.
AREAS OF PATCHY FREEZING DRIZZLE WILL REMAIN POSSIBLE OVER NORTHWEST
NEBRASKA THIS EVENING...OTHERWISE A CHANGE OVER TO ALL SNOW CAN BE
EXPECTED. SNOW WILL BE LIGHT AT FIRST...HOWEVER SNOWFALL WILL AT
TIMES BECOME MODERATE TO HEAVY. VSBY TO BE 3SM OR LESS FROM THE
FOG/FREEZING DRIZZLE OR SNOW. CIGS LESS THAN OVC020...GENERALLY AT
OR BELOW OVC010. VSBY AND CIGS MAY LIFT TO MVFR FOR A SHORT TIME
TOMORROW LATE MORNING OR EARLY AFTERNOON...BEFORE THE MAIN PART OF
THE SYSTEM SLIDES TO THE EAST OVER THE MISS RVR VALLEY AND A RETURN
TO IFR CONDITIONS.
&&
.LBF WATCHES/WARNINGS/ADVISORIES...WINTER STORM WARNING UNTIL 6 AM
CST /5 AM MST/ FRIDAY FOR NEZ004-022>024-035-036-056>058-069-070-094.
WINTER STORM WARNING UNTIL NOON CST FRIDAY FOR NEZ005>010-
025>029-037-038-059-071.
&&
$$
SHORT TERM...BUTTLER
AVIATION AND LONG TERM...MASEK
